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linux/fs/resctrl/rdtgroup.c

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x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Add an architectural hook called for first mount Enumeration of Intel telemetry events is an asynchronous process involving several mutually dependent drivers added as auxiliary devices during the device_initcall() phase of Linux boot. The process finishes after the probe functions of these drivers completes. But this happens after resctrl_arch_late_init() is executed. Tracing the enumeration process shows that it does complete a full seven seconds before the earliest possible mount of the resctrl file system (when included in /etc/fstab for automatic mount by systemd). Add a hook for use by telemetry event enumeration and initialization and run it once at the beginning of resctrl mount without any locks held. The architecture is responsible for any required locking. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/20260105191711.GBaVwON5nZn-uO6Sqg@fat_crate.local
2026-01-08 09:42:25 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Document safe RCU list traversal rdt_resource::ctrl_domains and rdt_resource::mon_domains are RCU lists with entries added and removed by architecture from CPU hotplug callbacks that are run with cpus_write_lock() held. These lists can be traversed safely from resctrl fs by either holding cpus_read_lock() or relying on an RCU read-side critical section. resctrl fs traversals of rdt_resource::ctrl_domains and rdt_resource::mon_domains are done using list_for_each_entry() with cpus_read_lock() held. Similarly, x86 architecture callbacks use list_for_each_entry() expecting that resctrl fs makes the call with cpus_read_lock() held. Inconsistently, a lockdep_assert_cpus_held() precedes the list_for_each_entry() call with varying distance to document this safe RCU list traversal. In preparation for an upcoming traversal of rdt_resource::ctrl_domains that needs to be done from RCU read-side critical section there is a requirement for developers to always know exactly in which context the list is being traversed. Replace the list_for_each_entry() traversals of RCU list with list_for_each_entry_rcu() to document that an RCU list is being traversed while making use of the built-in lockdep expression that additionally documents that it is cpus_read_lock() that enables the list to be traversed from non-RCU protection. Only revert to documenting the safety of traversal using a comment when lockdep does not have needed visibility in functions called via smp_call*(). The lockdep expression within list_for_each_entry_rcu() depends on RCU_EXPERT that is not set in a typical debug kernel so keep the existing lockdep_assert_cpus_held() that is active with CONFIG_LOCKDEP=y found in typical debug kernel. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://patch.msgid.link/d9373f8da8ffde667740e186ffc96ab69628ac9a.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:37 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Replace architecture event enabled checks The resctrl file system now has complete knowledge of the status of every event. So there is no need for per-event function calls to check. Replace each of the resctrl_arch_is_{event}enabled() calls with resctrl_is_mon_event_enabled(QOS_{EVENT}). No functional change. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:01 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Replace architecture event enabled checks The resctrl file system now has complete knowledge of the status of every event. So there is no need for per-event function calls to check. Replace each of the resctrl_arch_is_{event}enabled() calls with resctrl_is_mon_event_enabled(QOS_{EVENT}). No functional change. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:01 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Add user interface to enable/disable io_alloc feature AMD's SDCIAE forces all SDCI lines to be placed into the L3 cache portions identified by the highest-supported L3_MASK_n register, where n is the maximum supported CLOSID. To support this, when io_alloc resctrl feature is enabled, reserve the highest CLOSID exclusively for I/O allocation traffic making it no longer available for general CPU cache allocation. Introduce user interface to enable/disable io_alloc feature and encourage users to enable io_alloc only when running workloads that can benefit from this functionality. On enable, initialize the io_alloc CLOSID with all usable CBMs across all the domains. Since CLOSIDs are managed by resctrl fs, it is least invasive to make "io_alloc is supported by maximum supported CLOSID" part of the initial resctrl fs support for io_alloc. Take care to minimally (only in error messages) expose this use of CLOSID for io_alloc to user space so that this is not required from other architectures that may support io_alloc differently in the future. When resctrl is mounted with "-o cdp" to enable code/data prioritization, there are two L3 resources that can support I/O allocation: L3CODE and L3DATA. From resctrl fs perspective the two resources share a CLOSID and the architecture's available CLOSID are halved to support this. The architecture's underlying CLOSID used by SDCIAE when CDP is enabled is the CLOSID associated with the CDP_CODE resource, but from resctrl's perspective there is only one CLOSID for both CDP_CODE and CDP_DATA. CDP_DATA is thus not usable for general (CPU) cache allocation nor I/O allocation. Keep the CDP_CODE and CDP_DATA I/O alloc status in sync to avoid any confusion to user space. That is, enabling io_alloc on CDP_CODE does so on CDP_DATA and vice-versa, and keep the I/O allocation CBMs of CDP_CODE and CDP_DATA in sync. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://patch.msgid.link/c7d3037795e653e22b02d8fc73ca80d9b075031c.1762995456.git.babu.moger@amd.com
2025-11-12 18:57:32 -06:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Change last_cmd_status custom during input parsing A pattern of usage of last_cmd_status was introduced during its enabling in commit c377dcfbee80 ("x86/intel_rdt: Add diagnostics when writing the schemata file") and since copied throughout resctrl to result in the following custom: ..._write() { /* Early parsing of input, exit on failure. */ /* Obtain rdtgroup_mutex */ rdt_last_cmd_clear(); /* Clear last_cmd_status buffer */ /* * Act on user command, failures result in detail * error message in last_cmd_status buffer via * rdt_last_cmd_puts()/rdt_last_cmd_printf(). */ /* Release rdtgroup_mutex */ } If resctrl exits with failure during early parsing of input there are two possible scenarios: - The last_cmd_status buffer is empty and a user's read of info/last_cmd_status returns "ok". - The last_cmd_status buffer contains details from an earlier ...write() failure and a user's read of info/last_cmd_status returns this outdated error description. Writing to a resctrl file is considered a "resctrl command" and the resctrl documentation states the following about the last_cmd_status file: "If the command failed, it will provide more information that can be conveyed in the error returns from file operations." Neither of the current scenarios is correct behavior. Move early input parsing to be done with rdtgroup_mutex held after the last_cmd_status buffer is cleared. Let info/last_cmd_status be accurate when an error is encountered during parsing of user command. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Ben Horgan <ben.horgan@arm.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Tested-by: Babu Moger <babu.moger@amd.com> Link: https://patch.msgid.link/c9eba0ef3b9a72b845b4ae02ecd7c098ed8bf06f.1782857711.git.reinette.chatre@intel.com
2026-06-30 21:27:07 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Change last_cmd_status custom during input parsing A pattern of usage of last_cmd_status was introduced during its enabling in commit c377dcfbee80 ("x86/intel_rdt: Add diagnostics when writing the schemata file") and since copied throughout resctrl to result in the following custom: ..._write() { /* Early parsing of input, exit on failure. */ /* Obtain rdtgroup_mutex */ rdt_last_cmd_clear(); /* Clear last_cmd_status buffer */ /* * Act on user command, failures result in detail * error message in last_cmd_status buffer via * rdt_last_cmd_puts()/rdt_last_cmd_printf(). */ /* Release rdtgroup_mutex */ } If resctrl exits with failure during early parsing of input there are two possible scenarios: - The last_cmd_status buffer is empty and a user's read of info/last_cmd_status returns "ok". - The last_cmd_status buffer contains details from an earlier ...write() failure and a user's read of info/last_cmd_status returns this outdated error description. Writing to a resctrl file is considered a "resctrl command" and the resctrl documentation states the following about the last_cmd_status file: "If the command failed, it will provide more information that can be conveyed in the error returns from file operations." Neither of the current scenarios is correct behavior. Move early input parsing to be done with rdtgroup_mutex held after the last_cmd_status buffer is cleared. Let info/last_cmd_status be accurate when an error is encountered during parsing of user command. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Ben Horgan <ben.horgan@arm.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Tested-by: Babu Moger <babu.moger@amd.com> Link: https://patch.msgid.link/c9eba0ef3b9a72b845b4ae02ecd7c098ed8bf06f.1782857711.git.reinette.chatre@intel.com
2026-06-30 21:27:07 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Change last_cmd_status custom during input parsing A pattern of usage of last_cmd_status was introduced during its enabling in commit c377dcfbee80 ("x86/intel_rdt: Add diagnostics when writing the schemata file") and since copied throughout resctrl to result in the following custom: ..._write() { /* Early parsing of input, exit on failure. */ /* Obtain rdtgroup_mutex */ rdt_last_cmd_clear(); /* Clear last_cmd_status buffer */ /* * Act on user command, failures result in detail * error message in last_cmd_status buffer via * rdt_last_cmd_puts()/rdt_last_cmd_printf(). */ /* Release rdtgroup_mutex */ } If resctrl exits with failure during early parsing of input there are two possible scenarios: - The last_cmd_status buffer is empty and a user's read of info/last_cmd_status returns "ok". - The last_cmd_status buffer contains details from an earlier ...write() failure and a user's read of info/last_cmd_status returns this outdated error description. Writing to a resctrl file is considered a "resctrl command" and the resctrl documentation states the following about the last_cmd_status file: "If the command failed, it will provide more information that can be conveyed in the error returns from file operations." Neither of the current scenarios is correct behavior. Move early input parsing to be done with rdtgroup_mutex held after the last_cmd_status buffer is cleared. Let info/last_cmd_status be accurate when an error is encountered during parsing of user command. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Ben Horgan <ben.horgan@arm.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Tested-by: Babu Moger <babu.moger@amd.com> Link: https://patch.msgid.link/c9eba0ef3b9a72b845b4ae02ecd7c098ed8bf06f.1782857711.git.reinette.chatre@intel.com
2026-06-30 21:27:07 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Change last_cmd_status custom during input parsing A pattern of usage of last_cmd_status was introduced during its enabling in commit c377dcfbee80 ("x86/intel_rdt: Add diagnostics when writing the schemata file") and since copied throughout resctrl to result in the following custom: ..._write() { /* Early parsing of input, exit on failure. */ /* Obtain rdtgroup_mutex */ rdt_last_cmd_clear(); /* Clear last_cmd_status buffer */ /* * Act on user command, failures result in detail * error message in last_cmd_status buffer via * rdt_last_cmd_puts()/rdt_last_cmd_printf(). */ /* Release rdtgroup_mutex */ } If resctrl exits with failure during early parsing of input there are two possible scenarios: - The last_cmd_status buffer is empty and a user's read of info/last_cmd_status returns "ok". - The last_cmd_status buffer contains details from an earlier ...write() failure and a user's read of info/last_cmd_status returns this outdated error description. Writing to a resctrl file is considered a "resctrl command" and the resctrl documentation states the following about the last_cmd_status file: "If the command failed, it will provide more information that can be conveyed in the error returns from file operations." Neither of the current scenarios is correct behavior. Move early input parsing to be done with rdtgroup_mutex held after the last_cmd_status buffer is cleared. Let info/last_cmd_status be accurate when an error is encountered during parsing of user command. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Ben Horgan <ben.horgan@arm.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Tested-by: Babu Moger <babu.moger@amd.com> Link: https://patch.msgid.link/c9eba0ef3b9a72b845b4ae02ecd7c098ed8bf06f.1782857711.git.reinette.chatre@intel.com
2026-06-30 21:27:07 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Change last_cmd_status custom during input parsing A pattern of usage of last_cmd_status was introduced during its enabling in commit c377dcfbee80 ("x86/intel_rdt: Add diagnostics when writing the schemata file") and since copied throughout resctrl to result in the following custom: ..._write() { /* Early parsing of input, exit on failure. */ /* Obtain rdtgroup_mutex */ rdt_last_cmd_clear(); /* Clear last_cmd_status buffer */ /* * Act on user command, failures result in detail * error message in last_cmd_status buffer via * rdt_last_cmd_puts()/rdt_last_cmd_printf(). */ /* Release rdtgroup_mutex */ } If resctrl exits with failure during early parsing of input there are two possible scenarios: - The last_cmd_status buffer is empty and a user's read of info/last_cmd_status returns "ok". - The last_cmd_status buffer contains details from an earlier ...write() failure and a user's read of info/last_cmd_status returns this outdated error description. Writing to a resctrl file is considered a "resctrl command" and the resctrl documentation states the following about the last_cmd_status file: "If the command failed, it will provide more information that can be conveyed in the error returns from file operations." Neither of the current scenarios is correct behavior. Move early input parsing to be done with rdtgroup_mutex held after the last_cmd_status buffer is cleared. Let info/last_cmd_status be accurate when an error is encountered during parsing of user command. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Ben Horgan <ben.horgan@arm.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Tested-by: Babu Moger <babu.moger@amd.com> Link: https://patch.msgid.link/c9eba0ef3b9a72b845b4ae02ecd7c098ed8bf06f.1782857711.git.reinette.chatre@intel.com
2026-06-30 21:27:07 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Change last_cmd_status custom during input parsing A pattern of usage of last_cmd_status was introduced during its enabling in commit c377dcfbee80 ("x86/intel_rdt: Add diagnostics when writing the schemata file") and since copied throughout resctrl to result in the following custom: ..._write() { /* Early parsing of input, exit on failure. */ /* Obtain rdtgroup_mutex */ rdt_last_cmd_clear(); /* Clear last_cmd_status buffer */ /* * Act on user command, failures result in detail * error message in last_cmd_status buffer via * rdt_last_cmd_puts()/rdt_last_cmd_printf(). */ /* Release rdtgroup_mutex */ } If resctrl exits with failure during early parsing of input there are two possible scenarios: - The last_cmd_status buffer is empty and a user's read of info/last_cmd_status returns "ok". - The last_cmd_status buffer contains details from an earlier ...write() failure and a user's read of info/last_cmd_status returns this outdated error description. Writing to a resctrl file is considered a "resctrl command" and the resctrl documentation states the following about the last_cmd_status file: "If the command failed, it will provide more information that can be conveyed in the error returns from file operations." Neither of the current scenarios is correct behavior. Move early input parsing to be done with rdtgroup_mutex held after the last_cmd_status buffer is cleared. Let info/last_cmd_status be accurate when an error is encountered during parsing of user command. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Ben Horgan <ben.horgan@arm.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Tested-by: Babu Moger <babu.moger@amd.com> Link: https://patch.msgid.link/c9eba0ef3b9a72b845b4ae02ecd7c098ed8bf06f.1782857711.git.reinette.chatre@intel.com
2026-06-30 21:27:07 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Change last_cmd_status custom during input parsing A pattern of usage of last_cmd_status was introduced during its enabling in commit c377dcfbee80 ("x86/intel_rdt: Add diagnostics when writing the schemata file") and since copied throughout resctrl to result in the following custom: ..._write() { /* Early parsing of input, exit on failure. */ /* Obtain rdtgroup_mutex */ rdt_last_cmd_clear(); /* Clear last_cmd_status buffer */ /* * Act on user command, failures result in detail * error message in last_cmd_status buffer via * rdt_last_cmd_puts()/rdt_last_cmd_printf(). */ /* Release rdtgroup_mutex */ } If resctrl exits with failure during early parsing of input there are two possible scenarios: - The last_cmd_status buffer is empty and a user's read of info/last_cmd_status returns "ok". - The last_cmd_status buffer contains details from an earlier ...write() failure and a user's read of info/last_cmd_status returns this outdated error description. Writing to a resctrl file is considered a "resctrl command" and the resctrl documentation states the following about the last_cmd_status file: "If the command failed, it will provide more information that can be conveyed in the error returns from file operations." Neither of the current scenarios is correct behavior. Move early input parsing to be done with rdtgroup_mutex held after the last_cmd_status buffer is cleared. Let info/last_cmd_status be accurate when an error is encountered during parsing of user command. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Ben Horgan <ben.horgan@arm.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Tested-by: Babu Moger <babu.moger@amd.com> Link: https://patch.msgid.link/c9eba0ef3b9a72b845b4ae02ecd7c098ed8bf06f.1782857711.git.reinette.chatre@intel.com
2026-06-30 21:27:07 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Change last_cmd_status custom during input parsing A pattern of usage of last_cmd_status was introduced during its enabling in commit c377dcfbee80 ("x86/intel_rdt: Add diagnostics when writing the schemata file") and since copied throughout resctrl to result in the following custom: ..._write() { /* Early parsing of input, exit on failure. */ /* Obtain rdtgroup_mutex */ rdt_last_cmd_clear(); /* Clear last_cmd_status buffer */ /* * Act on user command, failures result in detail * error message in last_cmd_status buffer via * rdt_last_cmd_puts()/rdt_last_cmd_printf(). */ /* Release rdtgroup_mutex */ } If resctrl exits with failure during early parsing of input there are two possible scenarios: - The last_cmd_status buffer is empty and a user's read of info/last_cmd_status returns "ok". - The last_cmd_status buffer contains details from an earlier ...write() failure and a user's read of info/last_cmd_status returns this outdated error description. Writing to a resctrl file is considered a "resctrl command" and the resctrl documentation states the following about the last_cmd_status file: "If the command failed, it will provide more information that can be conveyed in the error returns from file operations." Neither of the current scenarios is correct behavior. Move early input parsing to be done with rdtgroup_mutex held after the last_cmd_status buffer is cleared. Let info/last_cmd_status be accurate when an error is encountered during parsing of user command. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Ben Horgan <ben.horgan@arm.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Tested-by: Babu Moger <babu.moger@amd.com> Link: https://patch.msgid.link/c9eba0ef3b9a72b845b4ae02ecd7c098ed8bf06f.1782857711.git.reinette.chatre@intel.com
2026-06-30 21:27:07 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Fix use-after-free during unmount During unmount or failure teardown all mon_data structures that contain monitoring event file private data are freed after which kernfs nodes are removed. However, the RDT_DELETED flag is never set for the statically allocated default resource group. A concurrent reader of an event file associated with the default resource group may, after dropping kernfs active protection, block on rdtgroup_mutex while unmount proceeds to free the file private data and destroy the kernfs node without waiting for the reader. When the mutex is released, the reader wakes up, observes that RDT_DELETED is not set for the default group, and dereferences the already-freed file private data. The scenario can be depicted as follows: CPU0 CPU1 /* * Default resource group's * monitoring data accessible via * kernfs file with kernfs_node::priv * pointing to a struct mon_data. * User opens the file for reading. */ rdtgroup_mondata_show() /* arch encounters fatal error */ rdtgroup_kn_lock_live() resctrl_exit() atomic_inc(&rdtgroup_default.waitcount) cpus_read_lock() kernfs_break_active_protection(kn) mutex_lock(&rdtgroup_mutex) cpus_read_lock() resctrl_fs_teardown() mutex_lock(&rdtgroup_mutex) rmdir_all_sub() mon_put_kn_priv() /* Delete all mon_data structures */ rdtgroup_destroy_root() kernfs_destroy_root() rdtgroup_default.kn = NULL mutex_unlock(&rdtgroup_mutex) /* * rdtgroup_default.flags is empty so * rdtgroup_kn_lock_live() returns * &rdtgroup_default */ md = of->kn->priv; /* md points to freed mon_data */ Set RDT_DELETED for the default group unconditionally since the flag does not lead to the freeing of this statically allocated group. Do not allow a new resctrl mount if there are any waiters on default group of previous mount. A new mount will re-initialize the default group that would appear to waiters from previous mount as though the default group is accessible causing them to access the mon_data structures from the previous mount that have been removed. Fixes: 2a6566038544 ("x86/resctrl: Expand the width of domid by replacing mon_data_bits") Closes: https://sashiko.dev/#/patchset/20260508182143.14592-1-tony.luck%40intel.com?part=2 [1] Reported-by: Sashiko <sashiko-bot@kernel.org> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Chen Yu <yu.c.chen@intel.com> Cc: <stable@kernel.org> Link: https://patch.msgid.link/49a2ca3ca688f27e1a646cf90e1dc69287021127.1783377598.git.reinette.chatre@intel.com
2026-07-06 15:46:22 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Fix use-after-free during unmount During unmount or failure teardown all mon_data structures that contain monitoring event file private data are freed after which kernfs nodes are removed. However, the RDT_DELETED flag is never set for the statically allocated default resource group. A concurrent reader of an event file associated with the default resource group may, after dropping kernfs active protection, block on rdtgroup_mutex while unmount proceeds to free the file private data and destroy the kernfs node without waiting for the reader. When the mutex is released, the reader wakes up, observes that RDT_DELETED is not set for the default group, and dereferences the already-freed file private data. The scenario can be depicted as follows: CPU0 CPU1 /* * Default resource group's * monitoring data accessible via * kernfs file with kernfs_node::priv * pointing to a struct mon_data. * User opens the file for reading. */ rdtgroup_mondata_show() /* arch encounters fatal error */ rdtgroup_kn_lock_live() resctrl_exit() atomic_inc(&rdtgroup_default.waitcount) cpus_read_lock() kernfs_break_active_protection(kn) mutex_lock(&rdtgroup_mutex) cpus_read_lock() resctrl_fs_teardown() mutex_lock(&rdtgroup_mutex) rmdir_all_sub() mon_put_kn_priv() /* Delete all mon_data structures */ rdtgroup_destroy_root() kernfs_destroy_root() rdtgroup_default.kn = NULL mutex_unlock(&rdtgroup_mutex) /* * rdtgroup_default.flags is empty so * rdtgroup_kn_lock_live() returns * &rdtgroup_default */ md = of->kn->priv; /* md points to freed mon_data */ Set RDT_DELETED for the default group unconditionally since the flag does not lead to the freeing of this statically allocated group. Do not allow a new resctrl mount if there are any waiters on default group of previous mount. A new mount will re-initialize the default group that would appear to waiters from previous mount as though the default group is accessible causing them to access the mon_data structures from the previous mount that have been removed. Fixes: 2a6566038544 ("x86/resctrl: Expand the width of domid by replacing mon_data_bits") Closes: https://sashiko.dev/#/patchset/20260508182143.14592-1-tony.luck%40intel.com?part=2 [1] Reported-by: Sashiko <sashiko-bot@kernel.org> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Chen Yu <yu.c.chen@intel.com> Cc: <stable@kernel.org> Link: https://patch.msgid.link/49a2ca3ca688f27e1a646cf90e1dc69287021127.1783377598.git.reinette.chatre@intel.com
2026-07-06 15:46:22 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Fix use-after-free during unmount During unmount or failure teardown all mon_data structures that contain monitoring event file private data are freed after which kernfs nodes are removed. However, the RDT_DELETED flag is never set for the statically allocated default resource group. A concurrent reader of an event file associated with the default resource group may, after dropping kernfs active protection, block on rdtgroup_mutex while unmount proceeds to free the file private data and destroy the kernfs node without waiting for the reader. When the mutex is released, the reader wakes up, observes that RDT_DELETED is not set for the default group, and dereferences the already-freed file private data. The scenario can be depicted as follows: CPU0 CPU1 /* * Default resource group's * monitoring data accessible via * kernfs file with kernfs_node::priv * pointing to a struct mon_data. * User opens the file for reading. */ rdtgroup_mondata_show() /* arch encounters fatal error */ rdtgroup_kn_lock_live() resctrl_exit() atomic_inc(&rdtgroup_default.waitcount) cpus_read_lock() kernfs_break_active_protection(kn) mutex_lock(&rdtgroup_mutex) cpus_read_lock() resctrl_fs_teardown() mutex_lock(&rdtgroup_mutex) rmdir_all_sub() mon_put_kn_priv() /* Delete all mon_data structures */ rdtgroup_destroy_root() kernfs_destroy_root() rdtgroup_default.kn = NULL mutex_unlock(&rdtgroup_mutex) /* * rdtgroup_default.flags is empty so * rdtgroup_kn_lock_live() returns * &rdtgroup_default */ md = of->kn->priv; /* md points to freed mon_data */ Set RDT_DELETED for the default group unconditionally since the flag does not lead to the freeing of this statically allocated group. Do not allow a new resctrl mount if there are any waiters on default group of previous mount. A new mount will re-initialize the default group that would appear to waiters from previous mount as though the default group is accessible causing them to access the mon_data structures from the previous mount that have been removed. Fixes: 2a6566038544 ("x86/resctrl: Expand the width of domid by replacing mon_data_bits") Closes: https://sashiko.dev/#/patchset/20260508182143.14592-1-tony.luck%40intel.com?part=2 [1] Reported-by: Sashiko <sashiko-bot@kernel.org> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Chen Yu <yu.c.chen@intel.com> Cc: <stable@kernel.org> Link: https://patch.msgid.link/49a2ca3ca688f27e1a646cf90e1dc69287021127.1783377598.git.reinette.chatre@intel.com
2026-07-06 15:46:22 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Inform user space when status buffer overflowed resctrl fs commands are becoming more powerful with, for example, a user able to use syntax like '*' to make broad configuration changes. Such commands that span multiple domains may result in more than one message printed to the last_cmd_status buffer with more planned. Issue "[truncated]" when displaying the last_cmd_status buffer to communicate if it overflowed. Upon encountering this, user space is expected to combine details about the failure found in info/last_cmd_status with related resctrl files to learn the accurate system state after the command failure. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Ben Horgan <ben.horgan@arm.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Tested-by: Babu Moger <babu.moger@amd.com> Link: https://patch.msgid.link/eb3d1aaa41d1f2bf6b1bb26ceafd52f04912121d.1782857711.git.reinette.chatre@intel.com
2026-06-30 21:27:10 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Inform user space when status buffer overflowed resctrl fs commands are becoming more powerful with, for example, a user able to use syntax like '*' to make broad configuration changes. Such commands that span multiple domains may result in more than one message printed to the last_cmd_status buffer with more planned. Issue "[truncated]" when displaying the last_cmd_status buffer to communicate if it overflowed. Upon encountering this, user space is expected to combine details about the failure found in info/last_cmd_status with related resctrl files to learn the accurate system state after the command failure. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Ben Horgan <ben.horgan@arm.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Tested-by: Babu Moger <babu.moger@amd.com> Link: https://patch.msgid.link/eb3d1aaa41d1f2bf6b1bb26ceafd52f04912121d.1782857711.git.reinette.chatre@intel.com
2026-06-30 21:27:10 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Inform user space when status buffer overflowed resctrl fs commands are becoming more powerful with, for example, a user able to use syntax like '*' to make broad configuration changes. Such commands that span multiple domains may result in more than one message printed to the last_cmd_status buffer with more planned. Issue "[truncated]" when displaying the last_cmd_status buffer to communicate if it overflowed. Upon encountering this, user space is expected to combine details about the failure found in info/last_cmd_status with related resctrl files to learn the accurate system state after the command failure. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Ben Horgan <ben.horgan@arm.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Tested-by: Babu Moger <babu.moger@amd.com> Link: https://patch.msgid.link/eb3d1aaa41d1f2bf6b1bb26ceafd52f04912121d.1782857711.git.reinette.chatre@intel.com
2026-06-30 21:27:10 -07:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Introduce the interface to display monitoring modes Introduce the resctrl file "mbm_assign_mode" to list the supported counter assignment modes. The "mbm_event" counter assignment mode allows users to assign a hardware counter to an RMID, event pair and monitor bandwidth usage as long as it is assigned. The hardware continues to track the assigned counter until it is explicitly unassigned by the user. Each event within a resctrl group can be assigned independently in this mode. On AMD systems "mbm_event" mode is backed by the ABMC (Assignable Bandwidth Monitoring Counters) hardware feature and is enabled by default. The "default" mode is the existing mode that works without the explicit counter assignment, instead relying on dynamic counter assignment by hardware that may result in hardware not dedicating a counter resulting in monitoring data reads returning "Unavailable". Provide an interface to display the monitor modes on the system. $ cat /sys/fs/resctrl/info/L3_MON/mbm_assign_mode [mbm_event] default Add IS_ENABLED(CONFIG_RESCTRL_ASSIGN_FIXED) check to support Arm64. On x86, CONFIG_RESCTRL_ASSIGN_FIXED is not defined. On Arm64, it will be defined when the "mbm_event" mode is supported. Add IS_ENABLED(CONFIG_RESCTRL_ASSIGN_FIXED) check early to ensure the user interface remains compatible with upcoming Arm64 support. IS_ENABLED() safely evaluates to 0 when the configuration is not defined. As a result, for MPAM, the display would be either: [default] or [mbm_event] Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:09 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Document safe RCU list traversal rdt_resource::ctrl_domains and rdt_resource::mon_domains are RCU lists with entries added and removed by architecture from CPU hotplug callbacks that are run with cpus_write_lock() held. These lists can be traversed safely from resctrl fs by either holding cpus_read_lock() or relying on an RCU read-side critical section. resctrl fs traversals of rdt_resource::ctrl_domains and rdt_resource::mon_domains are done using list_for_each_entry() with cpus_read_lock() held. Similarly, x86 architecture callbacks use list_for_each_entry() expecting that resctrl fs makes the call with cpus_read_lock() held. Inconsistently, a lockdep_assert_cpus_held() precedes the list_for_each_entry() call with varying distance to document this safe RCU list traversal. In preparation for an upcoming traversal of rdt_resource::ctrl_domains that needs to be done from RCU read-side critical section there is a requirement for developers to always know exactly in which context the list is being traversed. Replace the list_for_each_entry() traversals of RCU list with list_for_each_entry_rcu() to document that an RCU list is being traversed while making use of the built-in lockdep expression that additionally documents that it is cpus_read_lock() that enables the list to be traversed from non-RCU protection. Only revert to documenting the safety of traversal using a comment when lockdep does not have needed visibility in functions called via smp_call*(). The lockdep expression within list_for_each_entry_rcu() depends on RCU_EXPERT that is not set in a typical debug kernel so keep the existing lockdep_assert_cpus_held() that is active with CONFIG_LOCKDEP=y found in typical debug kernel. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://patch.msgid.link/d9373f8da8ffde667740e186ffc96ab69628ac9a.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:37 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Update bit_usage to reflect io_alloc The "shareable_bits" and "bit_usage" resctrl files associated with cache resources give insight into how instances of a cache is used. Update the annotated capacity bitmasks displayed by "bit_usage" to include the cache portions allocated for I/O via the "io_alloc" feature. "shareable_bits" is a global bitmask of shareable cache with I/O and can thus not present the per-domain I/O allocations possible with the "io_alloc" feature. Revise the "shareable_bits" documentation to direct users to "bit_usage" for accurate cache usage information. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://patch.msgid.link/e02a0d424129fd7f3e45822a559b1c614ae4652a.1762995456.git.babu.moger@amd.com
2025-11-12 18:57:36 -06:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Update bit_usage to reflect io_alloc The "shareable_bits" and "bit_usage" resctrl files associated with cache resources give insight into how instances of a cache is used. Update the annotated capacity bitmasks displayed by "bit_usage" to include the cache portions allocated for I/O via the "io_alloc" feature. "shareable_bits" is a global bitmask of shareable cache with I/O and can thus not present the per-domain I/O allocations possible with the "io_alloc" feature. Revise the "shareable_bits" documentation to direct users to "bit_usage" for accurate cache usage information. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://patch.msgid.link/e02a0d424129fd7f3e45822a559b1c614ae4652a.1762995456.git.babu.moger@amd.com
2025-11-12 18:57:36 -06:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Update bit_usage to reflect io_alloc The "shareable_bits" and "bit_usage" resctrl files associated with cache resources give insight into how instances of a cache is used. Update the annotated capacity bitmasks displayed by "bit_usage" to include the cache portions allocated for I/O via the "io_alloc" feature. "shareable_bits" is a global bitmask of shareable cache with I/O and can thus not present the per-domain I/O allocations possible with the "io_alloc" feature. Revise the "shareable_bits" documentation to direct users to "bit_usage" for accurate cache usage information. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://patch.msgid.link/e02a0d424129fd7f3e45822a559b1c614ae4652a.1762995456.git.babu.moger@amd.com
2025-11-12 18:57:36 -06:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86/resctrl: Handle number of RMIDs supported by RDT_RESOURCE_PERF_PKG There are now three meanings for "number of RMIDs": 1) The number for legacy features enumerated by CPUID leaf 0xF. This is the maximum number of distinct values that can be loaded into MSR_IA32_PQR_ASSOC. Note that systems with Sub-NUMA Cluster mode enabled will force scaling down the CPUID enumerated value by the number of SNC nodes per L3-cache. 2) The number of registers in MMIO space for each event. This is enumerated in the XML files and is the value initialized into event_group::num_rmid. 3) The number of "hardware counters" (this isn't a strictly accurate description of how things work, but serves as a useful analogy that does describe the limitations) feeding to those MMIO registers. This is enumerated in telemetry_region::num_rmids returned by intel_pmt_get_regions_by_feature(). Event groups with insufficient "hardware counters" to track all RMIDs are difficult for users to use, since the system may reassign "hardware counters" at any time. This means that users cannot reliably collect two consecutive event counts to compute the rate at which events are occurring. Disable such event groups by default. The user may override this with a command line "rdt=" option. In this case limit an under-resourced event group's number of possible monitor resource groups to the lowest number of "hardware counters". Scan all enabled event groups and assign the RDT_RESOURCE_PERF_PKG resource "num_rmid" value to the smallest of these values as this value will be used later to compare against the number of RMIDs supported by other resources to determine how many monitoring resource groups are supported. N.B. Change type of resctrl_mon::num_rmid to u32 to match its usage and the type of event_group::num_rmid so that min(r->num_rmid, e->num_rmid) won't complain about mixing signed and unsigned types. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:21:12 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Consolidate monitor event descriptions There are currently only three monitor events, all associated with the RDT_RESOURCE_L3 resource. Growing support for additional events will be easier with some restructuring to have a single point in file system code where all attributes of all events are defined. Place all event descriptions into an array mon_event_all[]. Doing this has the beneficial side effect of removing the need for rdt_resource::evt_list. Add resctrl_event_id::QOS_FIRST_EVENT for a lower bound on range checks for event ids and as the starting index to scan mon_event_all[]. Drop the code that builds evt_list and change the two places where the list is scanned to scan mon_event_all[] instead using a new helper macro for_each_mon_event(). Architecture code now informs file system code which events are available with resctrl_enable_mon_event(). Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:00 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Disable BMEC event configuration when mbm_event mode is enabled The BMEC (Bandwidth Monitoring Event Configuration) feature enables per-domain event configuration. With BMEC the MBM events are configured using the mbm_total_bytes_config or mbm_local_bytes_config files in /sys/fs/resctrl/info/L3_MON/ and the per-domain event configuration affects all monitor resource groups. The mbm_event counter assignment mode enables counters to be assigned to RMID (i.e. a monitor resource group), event pairs, with potentially unique event configurations associated with every counter. There may be systems that support both BMEC and mbm_event counter assignment mode, but resctrl supporting both concurrently will present a conflicting interface to the user with both per-domain and per RMID, event configurations active at the same time. The mbm_event counter assignment provides most flexibility to user space and aligns with Arm's counter support. On systems that support both, disable BMEC event configuration when mbm_event mode is enabled by hiding the mbm_total_bytes_config or mbm_local_bytes_config files when mbm_event mode is enabled. Ensure mon_features always displays accurate information about monitor features. Suggested-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:29 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
fs/resctrl: Add last_cmd_status support for writes to max_threshold_occupancy info/last_cmd_status is intended to contain more information if a write to any resctrl file fails. Writes to max_threshold_occupancy did not receive last_cmd_status support during initial last_cmd_status enabling. Add it now. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Tested-by: Babu Moger <babu.moger@amd.com> Link: https://patch.msgid.link/dfc60cf5324e15612db075b0987bd89c490fbad5.1782857711.git.reinette.chatre@intel.com
2026-06-30 21:27:08 -07:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
fs/resctrl: Add last_cmd_status support for writes to max_threshold_occupancy info/last_cmd_status is intended to contain more information if a write to any resctrl file fails. Writes to max_threshold_occupancy did not receive last_cmd_status support during initial last_cmd_status enabling. Add it now. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Tested-by: Babu Moger <babu.moger@amd.com> Link: https://patch.msgid.link/dfc60cf5324e15612db075b0987bd89c490fbad5.1782857711.git.reinette.chatre@intel.com
2026-06-30 21:27:08 -07:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Add user interface to enable/disable io_alloc feature AMD's SDCIAE forces all SDCI lines to be placed into the L3 cache portions identified by the highest-supported L3_MASK_n register, where n is the maximum supported CLOSID. To support this, when io_alloc resctrl feature is enabled, reserve the highest CLOSID exclusively for I/O allocation traffic making it no longer available for general CPU cache allocation. Introduce user interface to enable/disable io_alloc feature and encourage users to enable io_alloc only when running workloads that can benefit from this functionality. On enable, initialize the io_alloc CLOSID with all usable CBMs across all the domains. Since CLOSIDs are managed by resctrl fs, it is least invasive to make "io_alloc is supported by maximum supported CLOSID" part of the initial resctrl fs support for io_alloc. Take care to minimally (only in error messages) expose this use of CLOSID for io_alloc to user space so that this is not required from other architectures that may support io_alloc differently in the future. When resctrl is mounted with "-o cdp" to enable code/data prioritization, there are two L3 resources that can support I/O allocation: L3CODE and L3DATA. From resctrl fs perspective the two resources share a CLOSID and the architecture's available CLOSID are halved to support this. The architecture's underlying CLOSID used by SDCIAE when CDP is enabled is the CLOSID associated with the CDP_CODE resource, but from resctrl's perspective there is only one CLOSID for both CDP_CODE and CDP_DATA. CDP_DATA is thus not usable for general (CPU) cache allocation nor I/O allocation. Keep the CDP_CODE and CDP_DATA I/O alloc status in sync to avoid any confusion to user space. That is, enabling io_alloc on CDP_CODE does so on CDP_DATA and vice-versa, and keep the I/O allocation CBMs of CDP_CODE and CDP_DATA in sync. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://patch.msgid.link/c7d3037795e653e22b02d8fc73ca80d9b075031c.1762995456.git.babu.moger@amd.com
2025-11-12 18:57:32 -06:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Document safe RCU list traversal rdt_resource::ctrl_domains and rdt_resource::mon_domains are RCU lists with entries added and removed by architecture from CPU hotplug callbacks that are run with cpus_write_lock() held. These lists can be traversed safely from resctrl fs by either holding cpus_read_lock() or relying on an RCU read-side critical section. resctrl fs traversals of rdt_resource::ctrl_domains and rdt_resource::mon_domains are done using list_for_each_entry() with cpus_read_lock() held. Similarly, x86 architecture callbacks use list_for_each_entry() expecting that resctrl fs makes the call with cpus_read_lock() held. Inconsistently, a lockdep_assert_cpus_held() precedes the list_for_each_entry() call with varying distance to document this safe RCU list traversal. In preparation for an upcoming traversal of rdt_resource::ctrl_domains that needs to be done from RCU read-side critical section there is a requirement for developers to always know exactly in which context the list is being traversed. Replace the list_for_each_entry() traversals of RCU list with list_for_each_entry_rcu() to document that an RCU list is being traversed while making use of the built-in lockdep expression that additionally documents that it is cpus_read_lock() that enables the list to be traversed from non-RCU protection. Only revert to documenting the safety of traversal using a comment when lockdep does not have needed visibility in functions called via smp_call*(). The lockdep expression within list_for_each_entry_rcu() depends on RCU_EXPERT that is not set in a typical debug kernel so keep the existing lockdep_assert_cpus_held() that is active with CONFIG_LOCKDEP=y found in typical debug kernel. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://patch.msgid.link/d9373f8da8ffde667740e186ffc96ab69628ac9a.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:37 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Change last_cmd_status custom during input parsing A pattern of usage of last_cmd_status was introduced during its enabling in commit c377dcfbee80 ("x86/intel_rdt: Add diagnostics when writing the schemata file") and since copied throughout resctrl to result in the following custom: ..._write() { /* Early parsing of input, exit on failure. */ /* Obtain rdtgroup_mutex */ rdt_last_cmd_clear(); /* Clear last_cmd_status buffer */ /* * Act on user command, failures result in detail * error message in last_cmd_status buffer via * rdt_last_cmd_puts()/rdt_last_cmd_printf(). */ /* Release rdtgroup_mutex */ } If resctrl exits with failure during early parsing of input there are two possible scenarios: - The last_cmd_status buffer is empty and a user's read of info/last_cmd_status returns "ok". - The last_cmd_status buffer contains details from an earlier ...write() failure and a user's read of info/last_cmd_status returns this outdated error description. Writing to a resctrl file is considered a "resctrl command" and the resctrl documentation states the following about the last_cmd_status file: "If the command failed, it will provide more information that can be conveyed in the error returns from file operations." Neither of the current scenarios is correct behavior. Move early input parsing to be done with rdtgroup_mutex held after the last_cmd_status buffer is cleared. Let info/last_cmd_status be accurate when an error is encountered during parsing of user command. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Ben Horgan <ben.horgan@arm.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Tested-by: Babu Moger <babu.moger@amd.com> Link: https://patch.msgid.link/c9eba0ef3b9a72b845b4ae02ecd7c098ed8bf06f.1782857711.git.reinette.chatre@intel.com
2026-06-30 21:27:07 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Add missing return value descriptions Using the stricter "./tools/docs/kernel-doc -Wall -v" to verify proper formatting of documentation comments includes warnings related to return markup on functions that are omitted during the default verification checks. This stricter verification reports a couple of missing return descriptions in resctrl: Warning: .../fs/resctrl/rdtgroup.c:1536 No description found for return value of 'rdtgroup_cbm_to_size' Warning: .../fs/resctrl/rdtgroup.c:3131 No description found for return value of 'mon_get_kn_priv' Warning: .../fs/resctrl/rdtgroup.c:3523 No description found for return value of 'cbm_ensure_valid' Warning: .../fs/resctrl/monitor.c:238 No description found for return value of 'resctrl_find_cleanest_closid' Add the missing return descriptions. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://patch.msgid.link/1c50b9f7c73251c007133590986f127e1af57780.1775576382.git.reinette.chatre@intel.com
2026-04-07 09:01:59 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Document safe RCU list traversal rdt_resource::ctrl_domains and rdt_resource::mon_domains are RCU lists with entries added and removed by architecture from CPU hotplug callbacks that are run with cpus_write_lock() held. These lists can be traversed safely from resctrl fs by either holding cpus_read_lock() or relying on an RCU read-side critical section. resctrl fs traversals of rdt_resource::ctrl_domains and rdt_resource::mon_domains are done using list_for_each_entry() with cpus_read_lock() held. Similarly, x86 architecture callbacks use list_for_each_entry() expecting that resctrl fs makes the call with cpus_read_lock() held. Inconsistently, a lockdep_assert_cpus_held() precedes the list_for_each_entry() call with varying distance to document this safe RCU list traversal. In preparation for an upcoming traversal of rdt_resource::ctrl_domains that needs to be done from RCU read-side critical section there is a requirement for developers to always know exactly in which context the list is being traversed. Replace the list_for_each_entry() traversals of RCU list with list_for_each_entry_rcu() to document that an RCU list is being traversed while making use of the built-in lockdep expression that additionally documents that it is cpus_read_lock() that enables the list to be traversed from non-RCU protection. Only revert to documenting the safety of traversal using a comment when lockdep does not have needed visibility in functions called via smp_call*(). The lockdep expression within list_for_each_entry_rcu() depends on RCU_EXPERT that is not set in a typical debug kernel so keep the existing lockdep_assert_cpus_held() that is active with CONFIG_LOCKDEP=y found in typical debug kernel. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://patch.msgid.link/d9373f8da8ffde667740e186ffc96ab69628ac9a.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:37 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Rename struct rdt_mon_domain and rdt_hw_mon_domain The upcoming telemetry event monitoring is not tied to the L3 resource and will have a new domain structure. Rename the L3 resource specific domain data structures to include "l3_" in their names to avoid confusion between the different resource specific domain structures: rdt_mon_domain -> rdt_l3_mon_domain rdt_hw_mon_domain -> rdt_hw_l3_mon_domain No functional change. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:55 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Document safe RCU list traversal rdt_resource::ctrl_domains and rdt_resource::mon_domains are RCU lists with entries added and removed by architecture from CPU hotplug callbacks that are run with cpus_write_lock() held. These lists can be traversed safely from resctrl fs by either holding cpus_read_lock() or relying on an RCU read-side critical section. resctrl fs traversals of rdt_resource::ctrl_domains and rdt_resource::mon_domains are done using list_for_each_entry() with cpus_read_lock() held. Similarly, x86 architecture callbacks use list_for_each_entry() expecting that resctrl fs makes the call with cpus_read_lock() held. Inconsistently, a lockdep_assert_cpus_held() precedes the list_for_each_entry() call with varying distance to document this safe RCU list traversal. In preparation for an upcoming traversal of rdt_resource::ctrl_domains that needs to be done from RCU read-side critical section there is a requirement for developers to always know exactly in which context the list is being traversed. Replace the list_for_each_entry() traversals of RCU list with list_for_each_entry_rcu() to document that an RCU list is being traversed while making use of the built-in lockdep expression that additionally documents that it is cpus_read_lock() that enables the list to be traversed from non-RCU protection. Only revert to documenting the safety of traversal using a comment when lockdep does not have needed visibility in functions called via smp_call*(). The lockdep expression within list_for_each_entry_rcu() depends on RCU_EXPERT that is not set in a typical debug kernel so keep the existing lockdep_assert_cpus_held() that is active with CONFIG_LOCKDEP=y found in typical debug kernel. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://patch.msgid.link/d9373f8da8ffde667740e186ffc96ab69628ac9a.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:37 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Rename struct rdt_mon_domain and rdt_hw_mon_domain The upcoming telemetry event monitoring is not tied to the L3 resource and will have a new domain structure. Rename the L3 resource specific domain data structures to include "l3_" in their names to avoid confusion between the different resource specific domain structures: rdt_mon_domain -> rdt_l3_mon_domain rdt_hw_mon_domain -> rdt_hw_l3_mon_domain No functional change. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:55 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Rename struct rdt_mon_domain and rdt_hw_mon_domain The upcoming telemetry event monitoring is not tied to the L3 resource and will have a new domain structure. Rename the L3 resource specific domain data structures to include "l3_" in their names to avoid confusion between the different resource specific domain structures: rdt_mon_domain -> rdt_l3_mon_domain rdt_hw_mon_domain -> rdt_hw_l3_mon_domain No functional change. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:55 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Consolidate monitoring related data from rdt_resource The cache allocation and memory bandwidth allocation feature properties are consolidated into struct resctrl_cache and struct resctrl_membw respectively. In preparation for more monitoring properties that will clobber the existing resource struct more, re-organize the monitoring specific properties to also be in a separate structure. Also convert "bandwidth sources" terminology to "memory transactions" to have consistency within resctrl for related monitoring features. [ bp: Massage commit message. ] Suggested-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:06 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Consolidate monitoring related data from rdt_resource The cache allocation and memory bandwidth allocation feature properties are consolidated into struct resctrl_cache and struct resctrl_membw respectively. In preparation for more monitoring properties that will clobber the existing resource struct more, re-organize the monitoring specific properties to also be in a separate structure. Also convert "bandwidth sources" terminology to "memory transactions" to have consistency within resctrl for related monitoring features. [ bp: Massage commit message. ] Suggested-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:06 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Document safe RCU list traversal rdt_resource::ctrl_domains and rdt_resource::mon_domains are RCU lists with entries added and removed by architecture from CPU hotplug callbacks that are run with cpus_write_lock() held. These lists can be traversed safely from resctrl fs by either holding cpus_read_lock() or relying on an RCU read-side critical section. resctrl fs traversals of rdt_resource::ctrl_domains and rdt_resource::mon_domains are done using list_for_each_entry() with cpus_read_lock() held. Similarly, x86 architecture callbacks use list_for_each_entry() expecting that resctrl fs makes the call with cpus_read_lock() held. Inconsistently, a lockdep_assert_cpus_held() precedes the list_for_each_entry() call with varying distance to document this safe RCU list traversal. In preparation for an upcoming traversal of rdt_resource::ctrl_domains that needs to be done from RCU read-side critical section there is a requirement for developers to always know exactly in which context the list is being traversed. Replace the list_for_each_entry() traversals of RCU list with list_for_each_entry_rcu() to document that an RCU list is being traversed while making use of the built-in lockdep expression that additionally documents that it is cpus_read_lock() that enables the list to be traversed from non-RCU protection. Only revert to documenting the safety of traversal using a comment when lockdep does not have needed visibility in functions called via smp_call*(). The lockdep expression within list_for_each_entry_rcu() depends on RCU_EXPERT that is not set in a typical debug kernel so keep the existing lockdep_assert_cpus_held() that is active with CONFIG_LOCKDEP=y found in typical debug kernel. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://patch.msgid.link/d9373f8da8ffde667740e186ffc96ab69628ac9a.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:37 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Change last_cmd_status custom during input parsing A pattern of usage of last_cmd_status was introduced during its enabling in commit c377dcfbee80 ("x86/intel_rdt: Add diagnostics when writing the schemata file") and since copied throughout resctrl to result in the following custom: ..._write() { /* Early parsing of input, exit on failure. */ /* Obtain rdtgroup_mutex */ rdt_last_cmd_clear(); /* Clear last_cmd_status buffer */ /* * Act on user command, failures result in detail * error message in last_cmd_status buffer via * rdt_last_cmd_puts()/rdt_last_cmd_printf(). */ /* Release rdtgroup_mutex */ } If resctrl exits with failure during early parsing of input there are two possible scenarios: - The last_cmd_status buffer is empty and a user's read of info/last_cmd_status returns "ok". - The last_cmd_status buffer contains details from an earlier ...write() failure and a user's read of info/last_cmd_status returns this outdated error description. Writing to a resctrl file is considered a "resctrl command" and the resctrl documentation states the following about the last_cmd_status file: "If the command failed, it will provide more information that can be conveyed in the error returns from file operations." Neither of the current scenarios is correct behavior. Move early input parsing to be done with rdtgroup_mutex held after the last_cmd_status buffer is cleared. Let info/last_cmd_status be accurate when an error is encountered during parsing of user command. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Ben Horgan <ben.horgan@arm.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Tested-by: Babu Moger <babu.moger@amd.com> Link: https://patch.msgid.link/c9eba0ef3b9a72b845b4ae02ecd7c098ed8bf06f.1782857711.git.reinette.chatre@intel.com
2026-06-30 21:27:07 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Change last_cmd_status custom during input parsing A pattern of usage of last_cmd_status was introduced during its enabling in commit c377dcfbee80 ("x86/intel_rdt: Add diagnostics when writing the schemata file") and since copied throughout resctrl to result in the following custom: ..._write() { /* Early parsing of input, exit on failure. */ /* Obtain rdtgroup_mutex */ rdt_last_cmd_clear(); /* Clear last_cmd_status buffer */ /* * Act on user command, failures result in detail * error message in last_cmd_status buffer via * rdt_last_cmd_puts()/rdt_last_cmd_printf(). */ /* Release rdtgroup_mutex */ } If resctrl exits with failure during early parsing of input there are two possible scenarios: - The last_cmd_status buffer is empty and a user's read of info/last_cmd_status returns "ok". - The last_cmd_status buffer contains details from an earlier ...write() failure and a user's read of info/last_cmd_status returns this outdated error description. Writing to a resctrl file is considered a "resctrl command" and the resctrl documentation states the following about the last_cmd_status file: "If the command failed, it will provide more information that can be conveyed in the error returns from file operations." Neither of the current scenarios is correct behavior. Move early input parsing to be done with rdtgroup_mutex held after the last_cmd_status buffer is cleared. Let info/last_cmd_status be accurate when an error is encountered during parsing of user command. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Ben Horgan <ben.horgan@arm.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Tested-by: Babu Moger <babu.moger@amd.com> Link: https://patch.msgid.link/c9eba0ef3b9a72b845b4ae02ecd7c098ed8bf06f.1782857711.git.reinette.chatre@intel.com
2026-06-30 21:27:07 -07:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Change last_cmd_status custom during input parsing A pattern of usage of last_cmd_status was introduced during its enabling in commit c377dcfbee80 ("x86/intel_rdt: Add diagnostics when writing the schemata file") and since copied throughout resctrl to result in the following custom: ..._write() { /* Early parsing of input, exit on failure. */ /* Obtain rdtgroup_mutex */ rdt_last_cmd_clear(); /* Clear last_cmd_status buffer */ /* * Act on user command, failures result in detail * error message in last_cmd_status buffer via * rdt_last_cmd_puts()/rdt_last_cmd_printf(). */ /* Release rdtgroup_mutex */ } If resctrl exits with failure during early parsing of input there are two possible scenarios: - The last_cmd_status buffer is empty and a user's read of info/last_cmd_status returns "ok". - The last_cmd_status buffer contains details from an earlier ...write() failure and a user's read of info/last_cmd_status returns this outdated error description. Writing to a resctrl file is considered a "resctrl command" and the resctrl documentation states the following about the last_cmd_status file: "If the command failed, it will provide more information that can be conveyed in the error returns from file operations." Neither of the current scenarios is correct behavior. Move early input parsing to be done with rdtgroup_mutex held after the last_cmd_status buffer is cleared. Let info/last_cmd_status be accurate when an error is encountered during parsing of user command. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Ben Horgan <ben.horgan@arm.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Tested-by: Babu Moger <babu.moger@amd.com> Link: https://patch.msgid.link/c9eba0ef3b9a72b845b4ae02ecd7c098ed8bf06f.1782857711.git.reinette.chatre@intel.com
2026-06-30 21:27:07 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Change last_cmd_status custom during input parsing A pattern of usage of last_cmd_status was introduced during its enabling in commit c377dcfbee80 ("x86/intel_rdt: Add diagnostics when writing the schemata file") and since copied throughout resctrl to result in the following custom: ..._write() { /* Early parsing of input, exit on failure. */ /* Obtain rdtgroup_mutex */ rdt_last_cmd_clear(); /* Clear last_cmd_status buffer */ /* * Act on user command, failures result in detail * error message in last_cmd_status buffer via * rdt_last_cmd_puts()/rdt_last_cmd_printf(). */ /* Release rdtgroup_mutex */ } If resctrl exits with failure during early parsing of input there are two possible scenarios: - The last_cmd_status buffer is empty and a user's read of info/last_cmd_status returns "ok". - The last_cmd_status buffer contains details from an earlier ...write() failure and a user's read of info/last_cmd_status returns this outdated error description. Writing to a resctrl file is considered a "resctrl command" and the resctrl documentation states the following about the last_cmd_status file: "If the command failed, it will provide more information that can be conveyed in the error returns from file operations." Neither of the current scenarios is correct behavior. Move early input parsing to be done with rdtgroup_mutex held after the last_cmd_status buffer is cleared. Let info/last_cmd_status be accurate when an error is encountered during parsing of user command. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Ben Horgan <ben.horgan@arm.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Tested-by: Babu Moger <babu.moger@amd.com> Link: https://patch.msgid.link/c9eba0ef3b9a72b845b4ae02ecd7c098ed8bf06f.1782857711.git.reinette.chatre@intel.com
2026-06-30 21:27:07 -07:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Disable BMEC event configuration when mbm_event mode is enabled The BMEC (Bandwidth Monitoring Event Configuration) feature enables per-domain event configuration. With BMEC the MBM events are configured using the mbm_total_bytes_config or mbm_local_bytes_config files in /sys/fs/resctrl/info/L3_MON/ and the per-domain event configuration affects all monitor resource groups. The mbm_event counter assignment mode enables counters to be assigned to RMID (i.e. a monitor resource group), event pairs, with potentially unique event configurations associated with every counter. There may be systems that support both BMEC and mbm_event counter assignment mode, but resctrl supporting both concurrently will present a conflicting interface to the user with both per-domain and per RMID, event configurations active at the same time. The mbm_event counter assignment provides most flexibility to user space and aligns with Arm's counter support. On systems that support both, disable BMEC event configuration when mbm_event mode is enabled by hiding the mbm_total_bytes_config or mbm_local_bytes_config files when mbm_event mode is enabled. Ensure mon_features always displays accurate information about monitor features. Suggested-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:29 -05:00
fs/resctrl: Introduce the interface to switch between monitor modes Resctrl subsystem can support two monitoring modes, "mbm_event" or "default". In mbm_event mode, monitoring event can only accumulate data while it is backed by a hardware counter. In "default" mode, resctrl assumes there is a hardware counter for each event within every CTRL_MON and MON group. Introduce mbm_assign_mode resctrl file to switch between mbm_event and default modes. Example: To list the MBM monitor modes supported: $ cat /sys/fs/resctrl/info/L3_MON/mbm_assign_mode [mbm_event] default To enable the "mbm_event" counter assignment mode: $ echo "mbm_event" > /sys/fs/resctrl/info/L3_MON/mbm_assign_mode To enable the "default" monitoring mode: $ echo "default" > /sys/fs/resctrl/info/L3_MON/mbm_assign_mode Reset MBM event counters automatically as part of changing the mode. Clear both architectural and non-architectural event states to prevent overflow conditions during the next event read. Clear assignable counter configuration on all the domains. Also, enable auto assignment when switching to "mbm_event" mode. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:30 -05:00
fs/resctrl: Disable BMEC event configuration when mbm_event mode is enabled The BMEC (Bandwidth Monitoring Event Configuration) feature enables per-domain event configuration. With BMEC the MBM events are configured using the mbm_total_bytes_config or mbm_local_bytes_config files in /sys/fs/resctrl/info/L3_MON/ and the per-domain event configuration affects all monitor resource groups. The mbm_event counter assignment mode enables counters to be assigned to RMID (i.e. a monitor resource group), event pairs, with potentially unique event configurations associated with every counter. There may be systems that support both BMEC and mbm_event counter assignment mode, but resctrl supporting both concurrently will present a conflicting interface to the user with both per-domain and per RMID, event configurations active at the same time. The mbm_event counter assignment provides most flexibility to user space and aligns with Arm's counter support. On systems that support both, disable BMEC event configuration when mbm_event mode is enabled by hiding the mbm_total_bytes_config or mbm_local_bytes_config files when mbm_event mode is enabled. Ensure mon_features always displays accurate information about monitor features. Suggested-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:29 -05:00
fs/resctrl: Add user interface to enable/disable io_alloc feature AMD's SDCIAE forces all SDCI lines to be placed into the L3 cache portions identified by the highest-supported L3_MASK_n register, where n is the maximum supported CLOSID. To support this, when io_alloc resctrl feature is enabled, reserve the highest CLOSID exclusively for I/O allocation traffic making it no longer available for general CPU cache allocation. Introduce user interface to enable/disable io_alloc feature and encourage users to enable io_alloc only when running workloads that can benefit from this functionality. On enable, initialize the io_alloc CLOSID with all usable CBMs across all the domains. Since CLOSIDs are managed by resctrl fs, it is least invasive to make "io_alloc is supported by maximum supported CLOSID" part of the initial resctrl fs support for io_alloc. Take care to minimally (only in error messages) expose this use of CLOSID for io_alloc to user space so that this is not required from other architectures that may support io_alloc differently in the future. When resctrl is mounted with "-o cdp" to enable code/data prioritization, there are two L3 resources that can support I/O allocation: L3CODE and L3DATA. From resctrl fs perspective the two resources share a CLOSID and the architecture's available CLOSID are halved to support this. The architecture's underlying CLOSID used by SDCIAE when CDP is enabled is the CLOSID associated with the CDP_CODE resource, but from resctrl's perspective there is only one CLOSID for both CDP_CODE and CDP_DATA. CDP_DATA is thus not usable for general (CPU) cache allocation nor I/O allocation. Keep the CDP_CODE and CDP_DATA I/O alloc status in sync to avoid any confusion to user space. That is, enabling io_alloc on CDP_CODE does so on CDP_DATA and vice-versa, and keep the I/O allocation CBMs of CDP_CODE and CDP_DATA in sync. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://patch.msgid.link/c7d3037795e653e22b02d8fc73ca80d9b075031c.1762995456.git.babu.moger@amd.com
2025-11-12 18:57:32 -06:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Introduce mbm_assign_on_mkdir to enable assignments on mkdir The "mbm_event" counter assignment mode allows users to assign a hardware counter to an RMID, event pair and monitor the bandwidth as long as it is assigned. Introduce a user-configurable option that determines if a counter will automatically be assigned to an RMID, event pair when its associated monitor group is created via mkdir. Accessible when "mbm_event" counter assignment mode is enabled. Suggested-by: Peter Newman <peternewman@google.com> Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:25 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Introduce interface to display number of free MBM counters Introduce the "available_mbm_cntrs" resctrl file to display the number of counters available for assignment in each domain when "mbm_event" mode is enabled. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:12 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Add resctrl file to display number of assignable counters The "mbm_event" counter assignment mode allows users to assign a hardware counter to an RMID, event pair and monitor bandwidth usage as long as it is assigned. The hardware continues to track the assigned counter until it is explicitly unassigned by the user. Create 'num_mbm_cntrs' resctrl file that displays the number of counters supported in each domain. 'num_mbm_cntrs' is only visible to user space when the system supports "mbm_event" mode. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:10 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Introduce interface to display "io_alloc" support Introduce the "io_alloc" resctrl file to the "info" area of a cache resource, for example /sys/fs/resctrl/info/L3/io_alloc. "io_alloc" indicates support for the "io_alloc" feature that allows direct insertion of data from I/O devices into the cache. Restrict exposing support for "io_alloc" to the L3 resource that is the only resource where this feature can be backed by AMD's L3 Smart Data Cache Injection Allocation Enforcement (SDCIAE). With that, the "io_alloc" file is only visible to user space if the L3 resource supports "io_alloc". Doing so makes the file visible for all cache resources though, for example also L2 cache (if it supports cache allocation). As a consequence, add capability for file to report expected "enabled" and "disabled", as well as "not supported". Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://patch.msgid.link/e8b116a8f424128b227734bb1d433c14af478d90.1762995456.git.babu.moger@amd.com
2025-11-12 18:57:31 -06:00
fs/resctrl: Add user interface to enable/disable io_alloc feature AMD's SDCIAE forces all SDCI lines to be placed into the L3 cache portions identified by the highest-supported L3_MASK_n register, where n is the maximum supported CLOSID. To support this, when io_alloc resctrl feature is enabled, reserve the highest CLOSID exclusively for I/O allocation traffic making it no longer available for general CPU cache allocation. Introduce user interface to enable/disable io_alloc feature and encourage users to enable io_alloc only when running workloads that can benefit from this functionality. On enable, initialize the io_alloc CLOSID with all usable CBMs across all the domains. Since CLOSIDs are managed by resctrl fs, it is least invasive to make "io_alloc is supported by maximum supported CLOSID" part of the initial resctrl fs support for io_alloc. Take care to minimally (only in error messages) expose this use of CLOSID for io_alloc to user space so that this is not required from other architectures that may support io_alloc differently in the future. When resctrl is mounted with "-o cdp" to enable code/data prioritization, there are two L3 resources that can support I/O allocation: L3CODE and L3DATA. From resctrl fs perspective the two resources share a CLOSID and the architecture's available CLOSID are halved to support this. The architecture's underlying CLOSID used by SDCIAE when CDP is enabled is the CLOSID associated with the CDP_CODE resource, but from resctrl's perspective there is only one CLOSID for both CDP_CODE and CDP_DATA. CDP_DATA is thus not usable for general (CPU) cache allocation nor I/O allocation. Keep the CDP_CODE and CDP_DATA I/O alloc status in sync to avoid any confusion to user space. That is, enabling io_alloc on CDP_CODE does so on CDP_DATA and vice-versa, and keep the I/O allocation CBMs of CDP_CODE and CDP_DATA in sync. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://patch.msgid.link/c7d3037795e653e22b02d8fc73ca80d9b075031c.1762995456.git.babu.moger@amd.com
2025-11-12 18:57:32 -06:00
fs/resctrl: Introduce interface to display "io_alloc" support Introduce the "io_alloc" resctrl file to the "info" area of a cache resource, for example /sys/fs/resctrl/info/L3/io_alloc. "io_alloc" indicates support for the "io_alloc" feature that allows direct insertion of data from I/O devices into the cache. Restrict exposing support for "io_alloc" to the L3 resource that is the only resource where this feature can be backed by AMD's L3 Smart Data Cache Injection Allocation Enforcement (SDCIAE). With that, the "io_alloc" file is only visible to user space if the L3 resource supports "io_alloc". Doing so makes the file visible for all cache resources though, for example also L2 cache (if it supports cache allocation). As a consequence, add capability for file to report expected "enabled" and "disabled", as well as "not supported". Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://patch.msgid.link/e8b116a8f424128b227734bb1d433c14af478d90.1762995456.git.babu.moger@amd.com
2025-11-12 18:57:31 -06:00
fs/resctrl: Add user interface to enable/disable io_alloc feature AMD's SDCIAE forces all SDCI lines to be placed into the L3 cache portions identified by the highest-supported L3_MASK_n register, where n is the maximum supported CLOSID. To support this, when io_alloc resctrl feature is enabled, reserve the highest CLOSID exclusively for I/O allocation traffic making it no longer available for general CPU cache allocation. Introduce user interface to enable/disable io_alloc feature and encourage users to enable io_alloc only when running workloads that can benefit from this functionality. On enable, initialize the io_alloc CLOSID with all usable CBMs across all the domains. Since CLOSIDs are managed by resctrl fs, it is least invasive to make "io_alloc is supported by maximum supported CLOSID" part of the initial resctrl fs support for io_alloc. Take care to minimally (only in error messages) expose this use of CLOSID for io_alloc to user space so that this is not required from other architectures that may support io_alloc differently in the future. When resctrl is mounted with "-o cdp" to enable code/data prioritization, there are two L3 resources that can support I/O allocation: L3CODE and L3DATA. From resctrl fs perspective the two resources share a CLOSID and the architecture's available CLOSID are halved to support this. The architecture's underlying CLOSID used by SDCIAE when CDP is enabled is the CLOSID associated with the CDP_CODE resource, but from resctrl's perspective there is only one CLOSID for both CDP_CODE and CDP_DATA. CDP_DATA is thus not usable for general (CPU) cache allocation nor I/O allocation. Keep the CDP_CODE and CDP_DATA I/O alloc status in sync to avoid any confusion to user space. That is, enabling io_alloc on CDP_CODE does so on CDP_DATA and vice-versa, and keep the I/O allocation CBMs of CDP_CODE and CDP_DATA in sync. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://patch.msgid.link/c7d3037795e653e22b02d8fc73ca80d9b075031c.1762995456.git.babu.moger@amd.com
2025-11-12 18:57:32 -06:00
fs/resctrl: Introduce interface to display "io_alloc" support Introduce the "io_alloc" resctrl file to the "info" area of a cache resource, for example /sys/fs/resctrl/info/L3/io_alloc. "io_alloc" indicates support for the "io_alloc" feature that allows direct insertion of data from I/O devices into the cache. Restrict exposing support for "io_alloc" to the L3 resource that is the only resource where this feature can be backed by AMD's L3 Smart Data Cache Injection Allocation Enforcement (SDCIAE). With that, the "io_alloc" file is only visible to user space if the L3 resource supports "io_alloc". Doing so makes the file visible for all cache resources though, for example also L2 cache (if it supports cache allocation). As a consequence, add capability for file to report expected "enabled" and "disabled", as well as "not supported". Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://patch.msgid.link/e8b116a8f424128b227734bb1d433c14af478d90.1762995456.git.babu.moger@amd.com
2025-11-12 18:57:31 -06:00
fs/resctrl: Introduce interface to display io_alloc CBMs Introduce the "io_alloc_cbm" resctrl file to display the capacity bitmasks (CBMs) that represent the portions of each cache instance allocated for I/O traffic on a cache resource that supports the "io_alloc" feature. io_alloc_cbm resides in the info directory of a cache resource, for example, /sys/fs/resctrl/info/L3/. Since the resource name is part of the path, it is not necessary to display the resource name as done in the schemata file. When CDP is enabled, io_alloc routes traffic using the highest CLOSID associated with the CDP_CODE resource and that CLOSID becomes unusable for the CDP_DATA resource. The highest CLOSID of CDP_CODE and CDP_DATA resources will be kept in sync to ensure consistent user interface. In preparation for this, access the CBMs for I/O traffic through highest CLOSID of either CDP_CODE or CDP_DATA resource. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://patch.msgid.link/55a3ff66a70e7ce8239f022e62b334e9d64af604.1762995456.git.babu.moger@amd.com
2025-11-12 18:57:33 -06:00
fs/resctrl: Introduce interface to modify io_alloc capacity bitmasks The io_alloc feature in resctrl enables system software to configure the portion of the cache allocated for I/O traffic. When supported, the io_alloc_cbm file in resctrl provides access to capacity bitmasks (CBMs) allocated for I/O devices. Enable users to modify io_alloc CBMs by writing to the io_alloc_cbm resctrl file when the io_alloc feature is enabled. Mirror the CBMs between CDP_CODE and CDP_DATA when CDP is enabled to present consistent I/O allocation information to user space. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://patch.msgid.link/67609641b03ccfba18a8ee0bf9dbd1f3dcbecda3.1762995456.git.babu.moger@amd.com
2025-11-12 18:57:35 -06:00
fs/resctrl: Introduce interface to display io_alloc CBMs Introduce the "io_alloc_cbm" resctrl file to display the capacity bitmasks (CBMs) that represent the portions of each cache instance allocated for I/O traffic on a cache resource that supports the "io_alloc" feature. io_alloc_cbm resides in the info directory of a cache resource, for example, /sys/fs/resctrl/info/L3/. Since the resource name is part of the path, it is not necessary to display the resource name as done in the schemata file. When CDP is enabled, io_alloc routes traffic using the highest CLOSID associated with the CDP_CODE resource and that CLOSID becomes unusable for the CDP_DATA resource. The highest CLOSID of CDP_CODE and CDP_DATA resources will be kept in sync to ensure consistent user interface. In preparation for this, access the CBMs for I/O traffic through highest CLOSID of either CDP_CODE or CDP_DATA resource. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://patch.msgid.link/55a3ff66a70e7ce8239f022e62b334e9d64af604.1762995456.git.babu.moger@amd.com
2025-11-12 18:57:33 -06:00
fs/resctrl: Introduce interface to modify io_alloc capacity bitmasks The io_alloc feature in resctrl enables system software to configure the portion of the cache allocated for I/O traffic. When supported, the io_alloc_cbm file in resctrl provides access to capacity bitmasks (CBMs) allocated for I/O devices. Enable users to modify io_alloc CBMs by writing to the io_alloc_cbm resctrl file when the io_alloc feature is enabled. Mirror the CBMs between CDP_CODE and CDP_DATA when CDP is enabled to present consistent I/O allocation information to user space. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://patch.msgid.link/67609641b03ccfba18a8ee0bf9dbd1f3dcbecda3.1762995456.git.babu.moger@amd.com
2025-11-12 18:57:35 -06:00
fs/resctrl: Introduce interface to display io_alloc CBMs Introduce the "io_alloc_cbm" resctrl file to display the capacity bitmasks (CBMs) that represent the portions of each cache instance allocated for I/O traffic on a cache resource that supports the "io_alloc" feature. io_alloc_cbm resides in the info directory of a cache resource, for example, /sys/fs/resctrl/info/L3/. Since the resource name is part of the path, it is not necessary to display the resource name as done in the schemata file. When CDP is enabled, io_alloc routes traffic using the highest CLOSID associated with the CDP_CODE resource and that CLOSID becomes unusable for the CDP_DATA resource. The highest CLOSID of CDP_CODE and CDP_DATA resources will be kept in sync to ensure consistent user interface. In preparation for this, access the CBMs for I/O traffic through highest CLOSID of either CDP_CODE or CDP_DATA resource. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://patch.msgid.link/55a3ff66a70e7ce8239f022e62b334e9d64af604.1762995456.git.babu.moger@amd.com
2025-11-12 18:57:33 -06:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Add event configuration directory under info/L3_MON/ The "mbm_event" counter assignment mode allows the user to assign a hardware counter to an RMID, event pair and monitor the bandwidth as long as it is assigned. The user can specify the memory transaction(s) for the counter to track. When this mode is supported, the /sys/fs/resctrl/info/L3_MON/event_configs directory contains a sub-directory for each MBM event that can be assigned to a counter. The MBM event sub-directory contains a file named "event_filter" that is used to view and modify which memory transactions the MBM event is configured with. Create /sys/fs/resctrl/info/L3_MON/event_configs directory on resctrl mount and pre-populate it with directories for the two existing MBM events: mbm_total_bytes and mbm_local_bytes. Create the "event_filter" file within each MBM event directory with the needed *show() that displays the memory transactions with which the MBM event is configured. Example: $ mount -t resctrl resctrl /sys/fs/resctrl $ cd /sys/fs/resctrl/ $ cat info/L3_MON/event_configs/mbm_total_bytes/event_filter local_reads,remote_reads,local_non_temporal_writes, remote_non_temporal_writes,local_reads_slow_memory, remote_reads_slow_memory,dirty_victim_writes_all $ cat info/L3_MON/event_configs/mbm_local_bytes/event_filter local_reads,local_non_temporal_writes,local_reads_slow_memory Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:23 -05:00
x86,fs/resctrl: Create 'event_filter' files read only if they're not configurable When the counter assignment mode is mbm_event resctrl assumes the MBM events are configurable and exposes the 'event_filter' files. These files live at info/L3_MON/event_configs/<event>/event_filter and are used to display and set the event configuration. The MPAM architecture has support for configuring the memory bandwidth utilization (MBWU) counters to only count reads or only count writes. However, in MPAM, this event filtering support is optional in the hardware (and not yet implemented in the MPAM driver) but MBM counter assignment is always possible for MPAM MBWU counters. In order to support mbm_event mode with MPAM, create the 'event_filter' files read only if the event configuration can't be changed. A user can still chmod the file and so also return early with an error from event_filter_write(). Introduce a new monitor property, mbm_cntr_configurable, to indicate whether or not assignable MBM counters are configurable. On x86, set this to true whenever mbm_cntr_assignable is true to keep existing behaviour. Signed-off-by: Ben Horgan <ben.horgan@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Babu Moger <babu.moger@amd.com> Tested-by: Babu Moger <babu.moger@amd.com> Link: https://lore.kernel.org/20260506082855.3694761-1-ben.horgan@arm.com
2026-05-06 09:28:50 +01:00
fs/resctrl: Add event configuration directory under info/L3_MON/ The "mbm_event" counter assignment mode allows the user to assign a hardware counter to an RMID, event pair and monitor the bandwidth as long as it is assigned. The user can specify the memory transaction(s) for the counter to track. When this mode is supported, the /sys/fs/resctrl/info/L3_MON/event_configs directory contains a sub-directory for each MBM event that can be assigned to a counter. The MBM event sub-directory contains a file named "event_filter" that is used to view and modify which memory transactions the MBM event is configured with. Create /sys/fs/resctrl/info/L3_MON/event_configs directory on resctrl mount and pre-populate it with directories for the two existing MBM events: mbm_total_bytes and mbm_local_bytes. Create the "event_filter" file within each MBM event directory with the needed *show() that displays the memory transactions with which the MBM event is configured. Example: $ mount -t resctrl resctrl /sys/fs/resctrl $ cd /sys/fs/resctrl/ $ cat info/L3_MON/event_configs/mbm_total_bytes/event_filter local_reads,remote_reads,local_non_temporal_writes, remote_non_temporal_writes,local_reads_slow_memory, remote_reads_slow_memory,dirty_victim_writes_all $ cat info/L3_MON/event_configs/mbm_local_bytes/event_filter local_reads,local_non_temporal_writes,local_reads_slow_memory Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:23 -05:00
fs/resctrl: Provide interface to update the event configurations When "mbm_event" counter assignment mode is enabled, users can modify the event configuration by writing to the 'event_filter' resctrl file. The event configurations for mbm_event mode are located in /sys/fs/resctrl/info/L3_MON/event_configs/. Update the assignments of all CTRL_MON and MON resource groups when the event configuration is modified. Example: $ mount -t resctrl resctrl /sys/fs/resctrl $ cd /sys/fs/resctrl/ $ cat info/L3_MON/event_configs/mbm_local_bytes/event_filter local_reads,local_non_temporal_writes,local_reads_slow_memory $ echo "local_reads,local_non_temporal_writes" > info/L3_MON/event_configs/mbm_total_bytes/event_filter $ cat info/L3_MON/event_configs/mbm_total_bytes/event_filter local_reads,local_non_temporal_writes Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:24 -05:00
fs/resctrl: Add event configuration directory under info/L3_MON/ The "mbm_event" counter assignment mode allows the user to assign a hardware counter to an RMID, event pair and monitor the bandwidth as long as it is assigned. The user can specify the memory transaction(s) for the counter to track. When this mode is supported, the /sys/fs/resctrl/info/L3_MON/event_configs directory contains a sub-directory for each MBM event that can be assigned to a counter. The MBM event sub-directory contains a file named "event_filter" that is used to view and modify which memory transactions the MBM event is configured with. Create /sys/fs/resctrl/info/L3_MON/event_configs directory on resctrl mount and pre-populate it with directories for the two existing MBM events: mbm_total_bytes and mbm_local_bytes. Create the "event_filter" file within each MBM event directory with the needed *show() that displays the memory transactions with which the MBM event is configured. Example: $ mount -t resctrl resctrl /sys/fs/resctrl $ cd /sys/fs/resctrl/ $ cat info/L3_MON/event_configs/mbm_total_bytes/event_filter local_reads,remote_reads,local_non_temporal_writes, remote_non_temporal_writes,local_reads_slow_memory, remote_reads_slow_memory,dirty_victim_writes_all $ cat info/L3_MON/event_configs/mbm_local_bytes/event_filter local_reads,local_non_temporal_writes,local_reads_slow_memory Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:23 -05:00
fs/resctrl: Introduce mbm_L3_assignments to list assignments in a group Introduce the mbm_L3_assignments resctrl file associated with CTRL_MON and MON resource groups to display the counter assignment states of the resource group when "mbm_event" counter assignment mode is enabled. Display the list in the following format: <Event>:<Domain id>=<Assignment state>;<Domain id>=<Assignment state> Event: A valid MBM event listed in /sys/fs/resctrl/info/L3_MON/event_configs directory. Domain ID: A valid domain ID. The assignment state can be one of the following: _ : No counter assigned. e : Counter assigned exclusively. Example: To list the assignment states for the default group $ cd /sys/fs/resctrl $ cat /sys/fs/resctrl/mbm_L3_assignments mbm_total_bytes:0=e;1=e mbm_local_bytes:0=e;1=e Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:27 -05:00
fs/resctrl: Introduce the interface to modify assignments in a group Enable the mbm_l3_assignments resctrl file to be used to modify counter assignments of CTRL_MON and MON groups when the "mbm_event" counter assignment mode is enabled. Process the assignment modifications in the following format: <Event>:<Domain id>=<Assignment state>;<Domain id>=<Assignment state> Event: A valid MBM event in the /sys/fs/resctrl/info/L3_MON/event_configs directory. Domain ID: A valid domain ID. When writing, '*' applies the changes to all domains. Assignment states: _ : Unassign a counter. e : Assign a counter exclusively. Examples: $ cd /sys/fs/resctrl $ cat /sys/fs/resctrl/mbm_L3_assignments mbm_total_bytes:0=e;1=e mbm_local_bytes:0=e;1=e To unassign the counter associated with the mbm_total_bytes event on domain 0: $ echo "mbm_total_bytes:0=_" > mbm_L3_assignments $ cat /sys/fs/resctrl/mbm_L3_assignments mbm_total_bytes:0=_;1=e mbm_local_bytes:0=e;1=e To unassign the counter associated with the mbm_total_bytes event on all the domains: $ echo "mbm_total_bytes:*=_" > mbm_L3_assignments $ cat /sys/fs/resctrl/mbm_L3_assignments mbm_total_bytes:0=_;1=_ mbm_local_bytes:0=e;1=e Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:28 -05:00
fs/resctrl: Introduce mbm_L3_assignments to list assignments in a group Introduce the mbm_L3_assignments resctrl file associated with CTRL_MON and MON resource groups to display the counter assignment states of the resource group when "mbm_event" counter assignment mode is enabled. Display the list in the following format: <Event>:<Domain id>=<Assignment state>;<Domain id>=<Assignment state> Event: A valid MBM event listed in /sys/fs/resctrl/info/L3_MON/event_configs directory. Domain ID: A valid domain ID. The assignment state can be one of the following: _ : No counter assigned. e : Counter assigned exclusively. Example: To list the assignment states for the default group $ cd /sys/fs/resctrl $ cat /sys/fs/resctrl/mbm_L3_assignments mbm_total_bytes:0=e;1=e mbm_local_bytes:0=e;1=e Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:27 -05:00
fs/resctrl: Introduce the interface to modify assignments in a group Enable the mbm_l3_assignments resctrl file to be used to modify counter assignments of CTRL_MON and MON groups when the "mbm_event" counter assignment mode is enabled. Process the assignment modifications in the following format: <Event>:<Domain id>=<Assignment state>;<Domain id>=<Assignment state> Event: A valid MBM event in the /sys/fs/resctrl/info/L3_MON/event_configs directory. Domain ID: A valid domain ID. When writing, '*' applies the changes to all domains. Assignment states: _ : Unassign a counter. e : Assign a counter exclusively. Examples: $ cd /sys/fs/resctrl $ cat /sys/fs/resctrl/mbm_L3_assignments mbm_total_bytes:0=e;1=e mbm_local_bytes:0=e;1=e To unassign the counter associated with the mbm_total_bytes event on domain 0: $ echo "mbm_total_bytes:0=_" > mbm_L3_assignments $ cat /sys/fs/resctrl/mbm_L3_assignments mbm_total_bytes:0=_;1=e mbm_local_bytes:0=e;1=e To unassign the counter associated with the mbm_total_bytes event on all the domains: $ echo "mbm_total_bytes:*=_" > mbm_L3_assignments $ cat /sys/fs/resctrl/mbm_L3_assignments mbm_total_bytes:0=_;1=_ mbm_local_bytes:0=e;1=e Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:28 -05:00
fs/resctrl: Introduce mbm_L3_assignments to list assignments in a group Introduce the mbm_L3_assignments resctrl file associated with CTRL_MON and MON resource groups to display the counter assignment states of the resource group when "mbm_event" counter assignment mode is enabled. Display the list in the following format: <Event>:<Domain id>=<Assignment state>;<Domain id>=<Assignment state> Event: A valid MBM event listed in /sys/fs/resctrl/info/L3_MON/event_configs directory. Domain ID: A valid domain ID. The assignment state can be one of the following: _ : No counter assigned. e : Counter assigned exclusively. Example: To list the assignment states for the default group $ cd /sys/fs/resctrl $ cat /sys/fs/resctrl/mbm_L3_assignments mbm_total_bytes:0=e;1=e mbm_local_bytes:0=e;1=e Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:27 -05:00
fs/resctrl: Introduce the interface to display monitoring modes Introduce the resctrl file "mbm_assign_mode" to list the supported counter assignment modes. The "mbm_event" counter assignment mode allows users to assign a hardware counter to an RMID, event pair and monitor bandwidth usage as long as it is assigned. The hardware continues to track the assigned counter until it is explicitly unassigned by the user. Each event within a resctrl group can be assigned independently in this mode. On AMD systems "mbm_event" mode is backed by the ABMC (Assignable Bandwidth Monitoring Counters) hardware feature and is enabled by default. The "default" mode is the existing mode that works without the explicit counter assignment, instead relying on dynamic counter assignment by hardware that may result in hardware not dedicating a counter resulting in monitoring data reads returning "Unavailable". Provide an interface to display the monitor modes on the system. $ cat /sys/fs/resctrl/info/L3_MON/mbm_assign_mode [mbm_event] default Add IS_ENABLED(CONFIG_RESCTRL_ASSIGN_FIXED) check to support Arm64. On x86, CONFIG_RESCTRL_ASSIGN_FIXED is not defined. On Arm64, it will be defined when the "mbm_event" mode is supported. Add IS_ENABLED(CONFIG_RESCTRL_ASSIGN_FIXED) check early to ensure the user interface remains compatible with upcoming Arm64 support. IS_ENABLED() safely evaluates to 0 when the configuration is not defined. As a result, for MPAM, the display would be either: [default] or [mbm_event] Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:09 -05:00
fs/resctrl: Introduce the interface to switch between monitor modes Resctrl subsystem can support two monitoring modes, "mbm_event" or "default". In mbm_event mode, monitoring event can only accumulate data while it is backed by a hardware counter. In "default" mode, resctrl assumes there is a hardware counter for each event within every CTRL_MON and MON group. Introduce mbm_assign_mode resctrl file to switch between mbm_event and default modes. Example: To list the MBM monitor modes supported: $ cat /sys/fs/resctrl/info/L3_MON/mbm_assign_mode [mbm_event] default To enable the "mbm_event" counter assignment mode: $ echo "mbm_event" > /sys/fs/resctrl/info/L3_MON/mbm_assign_mode To enable the "default" monitoring mode: $ echo "default" > /sys/fs/resctrl/info/L3_MON/mbm_assign_mode Reset MBM event counters automatically as part of changing the mode. Clear both architectural and non-architectural event states to prevent overflow conditions during the next event read. Clear assignable counter configuration on all the domains. Also, enable auto assignment when switching to "mbm_event" mode. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:30 -05:00
fs/resctrl: Introduce the interface to display monitoring modes Introduce the resctrl file "mbm_assign_mode" to list the supported counter assignment modes. The "mbm_event" counter assignment mode allows users to assign a hardware counter to an RMID, event pair and monitor bandwidth usage as long as it is assigned. The hardware continues to track the assigned counter until it is explicitly unassigned by the user. Each event within a resctrl group can be assigned independently in this mode. On AMD systems "mbm_event" mode is backed by the ABMC (Assignable Bandwidth Monitoring Counters) hardware feature and is enabled by default. The "default" mode is the existing mode that works without the explicit counter assignment, instead relying on dynamic counter assignment by hardware that may result in hardware not dedicating a counter resulting in monitoring data reads returning "Unavailable". Provide an interface to display the monitor modes on the system. $ cat /sys/fs/resctrl/info/L3_MON/mbm_assign_mode [mbm_event] default Add IS_ENABLED(CONFIG_RESCTRL_ASSIGN_FIXED) check to support Arm64. On x86, CONFIG_RESCTRL_ASSIGN_FIXED is not defined. On Arm64, it will be defined when the "mbm_event" mode is supported. Add IS_ENABLED(CONFIG_RESCTRL_ASSIGN_FIXED) check early to ensure the user interface remains compatible with upcoming Arm64 support. IS_ENABLED() safely evaluates to 0 when the configuration is not defined. As a result, for MPAM, the display would be either: [default] or [mbm_event] Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:09 -05:00
fs/resctrl: Introduce the interface to switch between monitor modes Resctrl subsystem can support two monitoring modes, "mbm_event" or "default". In mbm_event mode, monitoring event can only accumulate data while it is backed by a hardware counter. In "default" mode, resctrl assumes there is a hardware counter for each event within every CTRL_MON and MON group. Introduce mbm_assign_mode resctrl file to switch between mbm_event and default modes. Example: To list the MBM monitor modes supported: $ cat /sys/fs/resctrl/info/L3_MON/mbm_assign_mode [mbm_event] default To enable the "mbm_event" counter assignment mode: $ echo "mbm_event" > /sys/fs/resctrl/info/L3_MON/mbm_assign_mode To enable the "default" monitoring mode: $ echo "default" > /sys/fs/resctrl/info/L3_MON/mbm_assign_mode Reset MBM event counters automatically as part of changing the mode. Clear both architectural and non-architectural event states to prevent overflow conditions during the next event read. Clear assignable counter configuration on all the domains. Also, enable auto assignment when switching to "mbm_event" mode. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:30 -05:00
fs/resctrl: Introduce the interface to display monitoring modes Introduce the resctrl file "mbm_assign_mode" to list the supported counter assignment modes. The "mbm_event" counter assignment mode allows users to assign a hardware counter to an RMID, event pair and monitor bandwidth usage as long as it is assigned. The hardware continues to track the assigned counter until it is explicitly unassigned by the user. Each event within a resctrl group can be assigned independently in this mode. On AMD systems "mbm_event" mode is backed by the ABMC (Assignable Bandwidth Monitoring Counters) hardware feature and is enabled by default. The "default" mode is the existing mode that works without the explicit counter assignment, instead relying on dynamic counter assignment by hardware that may result in hardware not dedicating a counter resulting in monitoring data reads returning "Unavailable". Provide an interface to display the monitor modes on the system. $ cat /sys/fs/resctrl/info/L3_MON/mbm_assign_mode [mbm_event] default Add IS_ENABLED(CONFIG_RESCTRL_ASSIGN_FIXED) check to support Arm64. On x86, CONFIG_RESCTRL_ASSIGN_FIXED is not defined. On Arm64, it will be defined when the "mbm_event" mode is supported. Add IS_ENABLED(CONFIG_RESCTRL_ASSIGN_FIXED) check early to ensure the user interface remains compatible with upcoming Arm64 support. IS_ENABLED() safely evaluates to 0 when the configuration is not defined. As a result, for MPAM, the display would be either: [default] or [mbm_event] Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:09 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Introduce interface to display "io_alloc" support Introduce the "io_alloc" resctrl file to the "info" area of a cache resource, for example /sys/fs/resctrl/info/L3/io_alloc. "io_alloc" indicates support for the "io_alloc" feature that allows direct insertion of data from I/O devices into the cache. Restrict exposing support for "io_alloc" to the L3 resource that is the only resource where this feature can be backed by AMD's L3 Smart Data Cache Injection Allocation Enforcement (SDCIAE). With that, the "io_alloc" file is only visible to user space if the L3 resource supports "io_alloc". Doing so makes the file visible for all cache resources though, for example also L2 cache (if it supports cache allocation). As a consequence, add capability for file to report expected "enabled" and "disabled", as well as "not supported". Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://patch.msgid.link/e8b116a8f424128b227734bb1d433c14af478d90.1762995456.git.babu.moger@amd.com
2025-11-12 18:57:31 -06:00
fs/resctrl: Introduce interface to display io_alloc CBMs Introduce the "io_alloc_cbm" resctrl file to display the capacity bitmasks (CBMs) that represent the portions of each cache instance allocated for I/O traffic on a cache resource that supports the "io_alloc" feature. io_alloc_cbm resides in the info directory of a cache resource, for example, /sys/fs/resctrl/info/L3/. Since the resource name is part of the path, it is not necessary to display the resource name as done in the schemata file. When CDP is enabled, io_alloc routes traffic using the highest CLOSID associated with the CDP_CODE resource and that CLOSID becomes unusable for the CDP_DATA resource. The highest CLOSID of CDP_CODE and CDP_DATA resources will be kept in sync to ensure consistent user interface. In preparation for this, access the CBMs for I/O traffic through highest CLOSID of either CDP_CODE or CDP_DATA resource. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://patch.msgid.link/55a3ff66a70e7ce8239f022e62b334e9d64af604.1762995456.git.babu.moger@amd.com
2025-11-12 18:57:33 -06:00
fs/resctrl: Introduce interface to display "io_alloc" support Introduce the "io_alloc" resctrl file to the "info" area of a cache resource, for example /sys/fs/resctrl/info/L3/io_alloc. "io_alloc" indicates support for the "io_alloc" feature that allows direct insertion of data from I/O devices into the cache. Restrict exposing support for "io_alloc" to the L3 resource that is the only resource where this feature can be backed by AMD's L3 Smart Data Cache Injection Allocation Enforcement (SDCIAE). With that, the "io_alloc" file is only visible to user space if the L3 resource supports "io_alloc". Doing so makes the file visible for all cache resources though, for example also L2 cache (if it supports cache allocation). As a consequence, add capability for file to report expected "enabled" and "disabled", as well as "not supported". Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://patch.msgid.link/e8b116a8f424128b227734bb1d433c14af478d90.1762995456.git.babu.moger@amd.com
2025-11-12 18:57:31 -06:00
fs/resctrl: Introduce interface to display io_alloc CBMs Introduce the "io_alloc_cbm" resctrl file to display the capacity bitmasks (CBMs) that represent the portions of each cache instance allocated for I/O traffic on a cache resource that supports the "io_alloc" feature. io_alloc_cbm resides in the info directory of a cache resource, for example, /sys/fs/resctrl/info/L3/. Since the resource name is part of the path, it is not necessary to display the resource name as done in the schemata file. When CDP is enabled, io_alloc routes traffic using the highest CLOSID associated with the CDP_CODE resource and that CLOSID becomes unusable for the CDP_DATA resource. The highest CLOSID of CDP_CODE and CDP_DATA resources will be kept in sync to ensure consistent user interface. In preparation for this, access the CBMs for I/O traffic through highest CLOSID of either CDP_CODE or CDP_DATA resource. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://patch.msgid.link/55a3ff66a70e7ce8239f022e62b334e9d64af604.1762995456.git.babu.moger@amd.com
2025-11-12 18:57:33 -06:00
fs/resctrl: Introduce interface to display "io_alloc" support Introduce the "io_alloc" resctrl file to the "info" area of a cache resource, for example /sys/fs/resctrl/info/L3/io_alloc. "io_alloc" indicates support for the "io_alloc" feature that allows direct insertion of data from I/O devices into the cache. Restrict exposing support for "io_alloc" to the L3 resource that is the only resource where this feature can be backed by AMD's L3 Smart Data Cache Injection Allocation Enforcement (SDCIAE). With that, the "io_alloc" file is only visible to user space if the L3 resource supports "io_alloc". Doing so makes the file visible for all cache resources though, for example also L2 cache (if it supports cache allocation). As a consequence, add capability for file to report expected "enabled" and "disabled", as well as "not supported". Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://patch.msgid.link/e8b116a8f424128b227734bb1d433c14af478d90.1762995456.git.babu.moger@amd.com
2025-11-12 18:57:31 -06:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Create 'event_filter' files read only if they're not configurable When the counter assignment mode is mbm_event resctrl assumes the MBM events are configurable and exposes the 'event_filter' files. These files live at info/L3_MON/event_configs/<event>/event_filter and are used to display and set the event configuration. The MPAM architecture has support for configuring the memory bandwidth utilization (MBWU) counters to only count reads or only count writes. However, in MPAM, this event filtering support is optional in the hardware (and not yet implemented in the MPAM driver) but MBM counter assignment is always possible for MPAM MBWU counters. In order to support mbm_event mode with MPAM, create the 'event_filter' files read only if the event configuration can't be changed. A user can still chmod the file and so also return early with an error from event_filter_write(). Introduce a new monitor property, mbm_cntr_configurable, to indicate whether or not assignable MBM counters are configurable. On x86, set this to true whenever mbm_cntr_assignable is true to keep existing behaviour. Signed-off-by: Ben Horgan <ben.horgan@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Babu Moger <babu.moger@amd.com> Tested-by: Babu Moger <babu.moger@amd.com> Link: https://lore.kernel.org/20260506082855.3694761-1-ben.horgan@arm.com
2026-05-06 09:28:50 +01:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Add event configuration directory under info/L3_MON/ The "mbm_event" counter assignment mode allows the user to assign a hardware counter to an RMID, event pair and monitor the bandwidth as long as it is assigned. The user can specify the memory transaction(s) for the counter to track. When this mode is supported, the /sys/fs/resctrl/info/L3_MON/event_configs directory contains a sub-directory for each MBM event that can be assigned to a counter. The MBM event sub-directory contains a file named "event_filter" that is used to view and modify which memory transactions the MBM event is configured with. Create /sys/fs/resctrl/info/L3_MON/event_configs directory on resctrl mount and pre-populate it with directories for the two existing MBM events: mbm_total_bytes and mbm_local_bytes. Create the "event_filter" file within each MBM event directory with the needed *show() that displays the memory transactions with which the MBM event is configured. Example: $ mount -t resctrl resctrl /sys/fs/resctrl $ cd /sys/fs/resctrl/ $ cat info/L3_MON/event_configs/mbm_total_bytes/event_filter local_reads,remote_reads,local_non_temporal_writes, remote_non_temporal_writes,local_reads_slow_memory, remote_reads_slow_memory,dirty_victim_writes_all $ cat info/L3_MON/event_configs/mbm_local_bytes/event_filter local_reads,local_non_temporal_writes,local_reads_slow_memory Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:23 -05:00
fs/resctrl: Tidy up the error path in resctrl_mkdir_event_configs() The error path in resctrl_mkdir_event_configs() is unnecessarily complicated. Simplify it to just return directly on error. Signed-off-by: Ben Horgan <ben.horgan@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Babu Moger <babu.moger@amd.com> Tested-by: Babu Moger <babu.moger@amd.com> Link: https://lore.kernel.org/r/20260506082855.3694761-1-ben.horgan@arm.com
2026-05-06 09:28:49 +01:00
fs/resctrl: Add event configuration directory under info/L3_MON/ The "mbm_event" counter assignment mode allows the user to assign a hardware counter to an RMID, event pair and monitor the bandwidth as long as it is assigned. The user can specify the memory transaction(s) for the counter to track. When this mode is supported, the /sys/fs/resctrl/info/L3_MON/event_configs directory contains a sub-directory for each MBM event that can be assigned to a counter. The MBM event sub-directory contains a file named "event_filter" that is used to view and modify which memory transactions the MBM event is configured with. Create /sys/fs/resctrl/info/L3_MON/event_configs directory on resctrl mount and pre-populate it with directories for the two existing MBM events: mbm_total_bytes and mbm_local_bytes. Create the "event_filter" file within each MBM event directory with the needed *show() that displays the memory transactions with which the MBM event is configured. Example: $ mount -t resctrl resctrl /sys/fs/resctrl $ cd /sys/fs/resctrl/ $ cat info/L3_MON/event_configs/mbm_total_bytes/event_filter local_reads,remote_reads,local_non_temporal_writes, remote_non_temporal_writes,local_reads_slow_memory, remote_reads_slow_memory,dirty_victim_writes_all $ cat info/L3_MON/event_configs/mbm_local_bytes/event_filter local_reads,local_non_temporal_writes,local_reads_slow_memory Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:23 -05:00
fs/resctrl: Tidy up the error path in resctrl_mkdir_event_configs() The error path in resctrl_mkdir_event_configs() is unnecessarily complicated. Simplify it to just return directly on error. Signed-off-by: Ben Horgan <ben.horgan@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Babu Moger <babu.moger@amd.com> Tested-by: Babu Moger <babu.moger@amd.com> Link: https://lore.kernel.org/r/20260506082855.3694761-1-ben.horgan@arm.com
2026-05-06 09:28:49 +01:00
fs/resctrl: Add event configuration directory under info/L3_MON/ The "mbm_event" counter assignment mode allows the user to assign a hardware counter to an RMID, event pair and monitor the bandwidth as long as it is assigned. The user can specify the memory transaction(s) for the counter to track. When this mode is supported, the /sys/fs/resctrl/info/L3_MON/event_configs directory contains a sub-directory for each MBM event that can be assigned to a counter. The MBM event sub-directory contains a file named "event_filter" that is used to view and modify which memory transactions the MBM event is configured with. Create /sys/fs/resctrl/info/L3_MON/event_configs directory on resctrl mount and pre-populate it with directories for the two existing MBM events: mbm_total_bytes and mbm_local_bytes. Create the "event_filter" file within each MBM event directory with the needed *show() that displays the memory transactions with which the MBM event is configured. Example: $ mount -t resctrl resctrl /sys/fs/resctrl $ cd /sys/fs/resctrl/ $ cat info/L3_MON/event_configs/mbm_total_bytes/event_filter local_reads,remote_reads,local_non_temporal_writes, remote_non_temporal_writes,local_reads_slow_memory, remote_reads_slow_memory,dirty_victim_writes_all $ cat info/L3_MON/event_configs/mbm_local_bytes/event_filter local_reads,local_non_temporal_writes,local_reads_slow_memory Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:23 -05:00
fs/resctrl: Tidy up the error path in resctrl_mkdir_event_configs() The error path in resctrl_mkdir_event_configs() is unnecessarily complicated. Simplify it to just return directly on error. Signed-off-by: Ben Horgan <ben.horgan@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Babu Moger <babu.moger@amd.com> Tested-by: Babu Moger <babu.moger@amd.com> Link: https://lore.kernel.org/r/20260506082855.3694761-1-ben.horgan@arm.com
2026-05-06 09:28:49 +01:00
fs/resctrl: Add event configuration directory under info/L3_MON/ The "mbm_event" counter assignment mode allows the user to assign a hardware counter to an RMID, event pair and monitor the bandwidth as long as it is assigned. The user can specify the memory transaction(s) for the counter to track. When this mode is supported, the /sys/fs/resctrl/info/L3_MON/event_configs directory contains a sub-directory for each MBM event that can be assigned to a counter. The MBM event sub-directory contains a file named "event_filter" that is used to view and modify which memory transactions the MBM event is configured with. Create /sys/fs/resctrl/info/L3_MON/event_configs directory on resctrl mount and pre-populate it with directories for the two existing MBM events: mbm_total_bytes and mbm_local_bytes. Create the "event_filter" file within each MBM event directory with the needed *show() that displays the memory transactions with which the MBM event is configured. Example: $ mount -t resctrl resctrl /sys/fs/resctrl $ cd /sys/fs/resctrl/ $ cat info/L3_MON/event_configs/mbm_total_bytes/event_filter local_reads,remote_reads,local_non_temporal_writes, remote_non_temporal_writes,local_reads_slow_memory, remote_reads_slow_memory,dirty_victim_writes_all $ cat info/L3_MON/event_configs/mbm_local_bytes/event_filter local_reads,local_non_temporal_writes,local_reads_slow_memory Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:23 -05:00
fs/resctrl: Tidy up the error path in resctrl_mkdir_event_configs() The error path in resctrl_mkdir_event_configs() is unnecessarily complicated. Simplify it to just return directly on error. Signed-off-by: Ben Horgan <ben.horgan@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Babu Moger <babu.moger@amd.com> Tested-by: Babu Moger <babu.moger@amd.com> Link: https://lore.kernel.org/r/20260506082855.3694761-1-ben.horgan@arm.com
2026-05-06 09:28:49 +01:00
fs/resctrl: Add event configuration directory under info/L3_MON/ The "mbm_event" counter assignment mode allows the user to assign a hardware counter to an RMID, event pair and monitor the bandwidth as long as it is assigned. The user can specify the memory transaction(s) for the counter to track. When this mode is supported, the /sys/fs/resctrl/info/L3_MON/event_configs directory contains a sub-directory for each MBM event that can be assigned to a counter. The MBM event sub-directory contains a file named "event_filter" that is used to view and modify which memory transactions the MBM event is configured with. Create /sys/fs/resctrl/info/L3_MON/event_configs directory on resctrl mount and pre-populate it with directories for the two existing MBM events: mbm_total_bytes and mbm_local_bytes. Create the "event_filter" file within each MBM event directory with the needed *show() that displays the memory transactions with which the MBM event is configured. Example: $ mount -t resctrl resctrl /sys/fs/resctrl $ cd /sys/fs/resctrl/ $ cat info/L3_MON/event_configs/mbm_total_bytes/event_filter local_reads,remote_reads,local_non_temporal_writes, remote_non_temporal_writes,local_reads_slow_memory, remote_reads_slow_memory,dirty_victim_writes_all $ cat info/L3_MON/event_configs/mbm_local_bytes/event_filter local_reads,local_non_temporal_writes,local_reads_slow_memory Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:23 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Add event configuration directory under info/L3_MON/ The "mbm_event" counter assignment mode allows the user to assign a hardware counter to an RMID, event pair and monitor the bandwidth as long as it is assigned. The user can specify the memory transaction(s) for the counter to track. When this mode is supported, the /sys/fs/resctrl/info/L3_MON/event_configs directory contains a sub-directory for each MBM event that can be assigned to a counter. The MBM event sub-directory contains a file named "event_filter" that is used to view and modify which memory transactions the MBM event is configured with. Create /sys/fs/resctrl/info/L3_MON/event_configs directory on resctrl mount and pre-populate it with directories for the two existing MBM events: mbm_total_bytes and mbm_local_bytes. Create the "event_filter" file within each MBM event directory with the needed *show() that displays the memory transactions with which the MBM event is configured. Example: $ mount -t resctrl resctrl /sys/fs/resctrl $ cd /sys/fs/resctrl/ $ cat info/L3_MON/event_configs/mbm_total_bytes/event_filter local_reads,remote_reads,local_non_temporal_writes, remote_non_temporal_writes,local_reads_slow_memory, remote_reads_slow_memory,dirty_victim_writes_all $ cat info/L3_MON/event_configs/mbm_local_bytes/event_filter local_reads,local_non_temporal_writes,local_reads_slow_memory Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:23 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Add event configuration directory under info/L3_MON/ The "mbm_event" counter assignment mode allows the user to assign a hardware counter to an RMID, event pair and monitor the bandwidth as long as it is assigned. The user can specify the memory transaction(s) for the counter to track. When this mode is supported, the /sys/fs/resctrl/info/L3_MON/event_configs directory contains a sub-directory for each MBM event that can be assigned to a counter. The MBM event sub-directory contains a file named "event_filter" that is used to view and modify which memory transactions the MBM event is configured with. Create /sys/fs/resctrl/info/L3_MON/event_configs directory on resctrl mount and pre-populate it with directories for the two existing MBM events: mbm_total_bytes and mbm_local_bytes. Create the "event_filter" file within each MBM event directory with the needed *show() that displays the memory transactions with which the MBM event is configured. Example: $ mount -t resctrl resctrl /sys/fs/resctrl $ cd /sys/fs/resctrl/ $ cat info/L3_MON/event_configs/mbm_total_bytes/event_filter local_reads,remote_reads,local_non_temporal_writes, remote_non_temporal_writes,local_reads_slow_memory, remote_reads_slow_memory,dirty_victim_writes_all $ cat info/L3_MON/event_configs/mbm_local_bytes/event_filter local_reads,local_non_temporal_writes,local_reads_slow_memory Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:23 -05:00
fs/resctrl: Disable BMEC event configuration when mbm_event mode is enabled The BMEC (Bandwidth Monitoring Event Configuration) feature enables per-domain event configuration. With BMEC the MBM events are configured using the mbm_total_bytes_config or mbm_local_bytes_config files in /sys/fs/resctrl/info/L3_MON/ and the per-domain event configuration affects all monitor resource groups. The mbm_event counter assignment mode enables counters to be assigned to RMID (i.e. a monitor resource group), event pairs, with potentially unique event configurations associated with every counter. There may be systems that support both BMEC and mbm_event counter assignment mode, but resctrl supporting both concurrently will present a conflicting interface to the user with both per-domain and per RMID, event configurations active at the same time. The mbm_event counter assignment provides most flexibility to user space and aligns with Arm's counter support. On systems that support both, disable BMEC event configuration when mbm_event mode is enabled by hiding the mbm_total_bytes_config or mbm_local_bytes_config files when mbm_event mode is enabled. Ensure mon_features always displays accurate information about monitor features. Suggested-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:29 -05:00
fs/resctrl: Add event configuration directory under info/L3_MON/ The "mbm_event" counter assignment mode allows the user to assign a hardware counter to an RMID, event pair and monitor the bandwidth as long as it is assigned. The user can specify the memory transaction(s) for the counter to track. When this mode is supported, the /sys/fs/resctrl/info/L3_MON/event_configs directory contains a sub-directory for each MBM event that can be assigned to a counter. The MBM event sub-directory contains a file named "event_filter" that is used to view and modify which memory transactions the MBM event is configured with. Create /sys/fs/resctrl/info/L3_MON/event_configs directory on resctrl mount and pre-populate it with directories for the two existing MBM events: mbm_total_bytes and mbm_local_bytes. Create the "event_filter" file within each MBM event directory with the needed *show() that displays the memory transactions with which the MBM event is configured. Example: $ mount -t resctrl resctrl /sys/fs/resctrl $ cd /sys/fs/resctrl/ $ cat info/L3_MON/event_configs/mbm_total_bytes/event_filter local_reads,remote_reads,local_non_temporal_writes, remote_non_temporal_writes,local_reads_slow_memory, remote_reads_slow_memory,dirty_victim_writes_all $ cat info/L3_MON/event_configs/mbm_local_bytes/event_filter local_reads,local_non_temporal_writes,local_reads_slow_memory Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:23 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Add and initialize a resource for package scope monitoring Add a new PERF_PKG resource and introduce package level scope for monitoring telemetry events so that CPU hotplug notifiers can build domains at the package granularity. Use the physical package ID available via topology_physical_package_id() to identify the monitoring domains with package level scope. This enables user space to use: /sys/devices/system/cpu/cpuX/topology/physical_package_id to identify the monitoring domain a CPU is associated with. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:21:01 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Disallow the software controller when MBM counters are assignable The software controller requires that there is one MBM counter per monitor group that is assigned to the event backing the software controller, as per mba_MBps_event. When mbm_event mode is in use, it is not guaranteed that any particular event will have an assigned counter. Currently, only AMD systems support counter assignment, but the MBA delay is non-linear and so the software controller is never supported anyway. On MPAM systems, the MBA delay is linear and so the software controller could be supported. The MPAM driver, unless a need arises, will not support the 'default' mbm_assign_mode and will always use the 'mbm_event' mode for memory bandwidth monitoring. Rather than develop a way to guarantee the counter assignment requirements needed by the software controller, take the pragmatic approach. Don't allow the software controller to be used at the same time as 'mbm_event' mode. As MPAM is the only relevant architecture and it will use 'mbm_event' mode whenever there are assignable MBM counters, for simplicity's sake, don't allow the software controller when the MBM counters are assignable. Implement this by failing the mount if the user requests the software controller, the mba_MBps option, and the MBM counters are assignable. Signed-off-by: Ben Horgan <ben.horgan@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Babu Moger <babu.moger@amd.com> Tested-by: Babu Moger <babu.moger@amd.com> Link: https://lore.kernel.org/20260506082855.3694761-1-ben.horgan@arm.com
2026-05-06 09:28:51 +01:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Disallow the software controller when MBM counters are assignable The software controller requires that there is one MBM counter per monitor group that is assigned to the event backing the software controller, as per mba_MBps_event. When mbm_event mode is in use, it is not guaranteed that any particular event will have an assigned counter. Currently, only AMD systems support counter assignment, but the MBA delay is non-linear and so the software controller is never supported anyway. On MPAM systems, the MBA delay is linear and so the software controller could be supported. The MPAM driver, unless a need arises, will not support the 'default' mbm_assign_mode and will always use the 'mbm_event' mode for memory bandwidth monitoring. Rather than develop a way to guarantee the counter assignment requirements needed by the software controller, take the pragmatic approach. Don't allow the software controller to be used at the same time as 'mbm_event' mode. As MPAM is the only relevant architecture and it will use 'mbm_event' mode whenever there are assignable MBM counters, for simplicity's sake, don't allow the software controller when the MBM counters are assignable. Implement this by failing the mount if the user requests the software controller, the mba_MBps option, and the MBM counters are assignable. Signed-off-by: Ben Horgan <ben.horgan@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Babu Moger <babu.moger@amd.com> Tested-by: Babu Moger <babu.moger@amd.com> Link: https://lore.kernel.org/20260506082855.3694761-1-ben.horgan@arm.com
2026-05-06 09:28:51 +01:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Document safe RCU list traversal rdt_resource::ctrl_domains and rdt_resource::mon_domains are RCU lists with entries added and removed by architecture from CPU hotplug callbacks that are run with cpus_write_lock() held. These lists can be traversed safely from resctrl fs by either holding cpus_read_lock() or relying on an RCU read-side critical section. resctrl fs traversals of rdt_resource::ctrl_domains and rdt_resource::mon_domains are done using list_for_each_entry() with cpus_read_lock() held. Similarly, x86 architecture callbacks use list_for_each_entry() expecting that resctrl fs makes the call with cpus_read_lock() held. Inconsistently, a lockdep_assert_cpus_held() precedes the list_for_each_entry() call with varying distance to document this safe RCU list traversal. In preparation for an upcoming traversal of rdt_resource::ctrl_domains that needs to be done from RCU read-side critical section there is a requirement for developers to always know exactly in which context the list is being traversed. Replace the list_for_each_entry() traversals of RCU list with list_for_each_entry_rcu() to document that an RCU list is being traversed while making use of the built-in lockdep expression that additionally documents that it is cpus_read_lock() that enables the list to be traversed from non-RCU protection. Only revert to documenting the safety of traversal using a comment when lockdep does not have needed visibility in functions called via smp_call*(). The lockdep expression within list_for_each_entry_rcu() depends on RCU_EXPERT that is not set in a typical debug kernel so keep the existing lockdep_assert_cpus_held() that is active with CONFIG_LOCKDEP=y found in typical debug kernel. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://patch.msgid.link/d9373f8da8ffde667740e186ffc96ab69628ac9a.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:37 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent use-after-free in rdtgroup_kn_put() A struct rdtgroup is reference counted via rdtgroup::waitcount. Callers that need the structure to remain valid across a sleep (while waiting on acquiring rdtgroup_mutex) take a reference with rdtgroup_kn_get() and release it with rdtgroup_kn_put(). The release path is intended to serve as the fallback freer: if the count drops to zero and the group has already been marked RDT_DELETED, rdtgroup_kn_put() frees the structure. The bulk teardown paths free_all_child_rdtgrp() and rmdir_all_sub() resulting from a resctrl directory remove or resctrl fs unmount act as the primary freer: they hold rdtgroup_mutex and free each rdtgroup whose waitcount is zero, otherwise they set RDT_DELETED and leave the freeing to the last waiter. These two freers race. rdtgroup_kn_put() commits waitcount == 0 with atomic_dec_and_test() outside rdtgroup_mutex, then reads rdtgroup::flags. Between those two operations a concurrent caller of free_all_child_rdtgrp() or rmdir_all_sub() (which holds the mutex) can observe waitcount == 0 via atomic_read(), call rdtgroup_remove(), and kfree() the structure. The subsequent read of rdtgroup::flags in rdtgroup_kn_put() is then a use-after-free, and the structure may even be freed twice if the freed memory happens to satisfy the RDT_DELETED flag check. Replace the bare atomic_dec_and_test() with atomic_dec_and_mutex_lock() so that the decrement-to-zero takes rdtgroup_mutex before the count becomes globally visible. The inspection of rdtgroup::flags then runs under the same mutex held by the bulk freers, making the two paths mutually exclusive. The common case where the count does not reach zero remains lock-free. Defer kernfs_unbreak_active_protection() until after the mutex is dropped since kernfs active protections functionally wrap rdtgroup_mutex. Remove resource group, which in turn drops its kernfs reference, after kernfs protection is restored. [ bp: Split the commit messsages into smaller, easier-parseable paragraphs. ] Fixes: b8511ccc75c0 ("x86/resctrl: Fix use-after-free when deleting resource groups") Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=1 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Ben Horgan <ben.horgan@arm.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/8d028bbea582dc382a4cc166b235f75bd5901aea.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:40 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Communicate resource group deleted error via last_cmd_status User space expects last_cmd_status to contain additional information if any resctrl command fails. A resctrl command may be blocked on the rdtgroup_mutex waiting for another command to finish and find that once the mutex is available that the resource group has since been deleted. In this scenario the command will fail while last_cmd_status contains either "ok" if the last_cmd_status buffer is empty or an outdated error from a previous command failure if last_cmd_status buffer has content. Include clearing of last_cmd_status buffer as part of rdtgroup_kn_lock_live() that is used to obtain access and needed locking to a resource group before attempting a command on the group. With the last_cmd_status buffer ready, provide an appropriate message to user space if the resource group has been deleted. No last_cmd_status treatment is needed for the remaining failure of rdtgroup_kn_lock_live() encountering a non-existent resource group since that could only occur during an attempt to obtain a resource group lock on a file in info/ which is an invalid usage. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Tested-by: Babu Moger <babu.moger@amd.com> Link: https://patch.msgid.link/9982141ec6f3ec18e0c53d7feabb19651583cf0e.1782857711.git.reinette.chatre@intel.com
2026-06-30 21:27:09 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Communicate resource group deleted error via last_cmd_status User space expects last_cmd_status to contain additional information if any resctrl command fails. A resctrl command may be blocked on the rdtgroup_mutex waiting for another command to finish and find that once the mutex is available that the resource group has since been deleted. In this scenario the command will fail while last_cmd_status contains either "ok" if the last_cmd_status buffer is empty or an outdated error from a previous command failure if last_cmd_status buffer has content. Include clearing of last_cmd_status buffer as part of rdtgroup_kn_lock_live() that is used to obtain access and needed locking to a resource group before attempting a command on the group. With the last_cmd_status buffer ready, provide an appropriate message to user space if the resource group has been deleted. No last_cmd_status treatment is needed for the remaining failure of rdtgroup_kn_lock_live() encountering a non-existent resource group since that could only occur during an attempt to obtain a resource group lock on a file in info/ which is an invalid usage. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Tested-by: Babu Moger <babu.moger@amd.com> Link: https://patch.msgid.link/9982141ec6f3ec18e0c53d7feabb19651583cf0e.1782857711.git.reinette.chatre@intel.com
2026-06-30 21:27:09 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Communicate resource group deleted error via last_cmd_status User space expects last_cmd_status to contain additional information if any resctrl command fails. A resctrl command may be blocked on the rdtgroup_mutex waiting for another command to finish and find that once the mutex is available that the resource group has since been deleted. In this scenario the command will fail while last_cmd_status contains either "ok" if the last_cmd_status buffer is empty or an outdated error from a previous command failure if last_cmd_status buffer has content. Include clearing of last_cmd_status buffer as part of rdtgroup_kn_lock_live() that is used to obtain access and needed locking to a resource group before attempting a command on the group. With the last_cmd_status buffer ready, provide an appropriate message to user space if the resource group has been deleted. No last_cmd_status treatment is needed for the remaining failure of rdtgroup_kn_lock_live() encountering a non-existent resource group since that could only occur during an attempt to obtain a resource group lock on a file in info/ which is an invalid usage. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Tested-by: Babu Moger <babu.moger@amd.com> Link: https://patch.msgid.link/9982141ec6f3ec18e0c53d7feabb19651583cf0e.1782857711.git.reinette.chatre@intel.com
2026-06-30 21:27:09 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Prevent deadlock and use-after-free in info file handlers resctrl provides files under the info/ directory to expose global configuration and capabilities to userspace. These files are instantiated statically during filesystem mount and expose data associated with internal schema structures via kernfs private pointers. A potential deadlock exists between userspace readers of these info files and the unmount filesystem teardown process. Reading an info file invokes kernfs which acquires an active reference, after which the handler typically attempts to acquire the rdtgroup_mutex. Concurrently, unmounting the filesystem holds the rdtgroup_mutex and then attempts to recursively remove the info kernfs nodes involving kernfs_drain() which blocks until all active references are released. Another problem exists where info files might be accessed from an outdated mount if the filesystem is unmounted and remounted during a reader's execution, leading to a use-after-free when reading the now-deleted private schema data. Introduce info_kn_lock() and info_kn_unlock() helpers to coordinate locking across all info handlers. These helpers mirror similar logic used by resource group handlers by deliberately breaking the kernfs active protection before attempting to acquire the rdtgroup_mutex, preventing the deadlock. To guard against the vulnerability from rapid mount cycling, info_kn_lock() securely walks the parent lineage of the kernfs node under an RCU section to confirm the node belongs to the globally active root before permitting the operation to proceed. Convert all info file handlers to use this helper and only de-reference the schema after it is determined safe to do so. Make no attempt to output an error message to last_cmd_status on failure since failure implies there is no filesystem with which to display the error to user space. [ bp: Massage commit message. ] Closes: https://sashiko.dev/#/patchset/20260515193944.15114-1-tony.luck%40intel.com?part=3 Reported-by: Sashiko <sashiko-bot@kernel.org> Assisted-by: GitHub_Copilot:gemini-3.1-pro Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://patch.msgid.link/0b5238486bd058704d908d39a75aff2815bd18aa.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:41 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
Convert 'alloc_obj' family to use the new default GFP_KERNEL argument This was done entirely with mindless brute force, using git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' | xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/' to convert the new alloc_obj() users that had a simple GFP_KERNEL argument to just drop that argument. Note that due to the extreme simplicity of the scripting, any slightly more complex cases spread over multiple lines would not be triggered: they definitely exist, but this covers the vast bulk of the cases, and the resulting diff is also then easier to check automatically. For the same reason the 'flex' versions will be done as a separate conversion. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2026-02-21 16:37:42 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Move functions to avoid forward references in subsequent fixes rdt_get_tree() manages resctrl fs mount and rdt_kill_sb() manages resctrl fs unmount. There is significant overlap between error cleanup during resctrl mount failure and cleanup on resctrl unmount yet the cleanup is not done consistently in these two flows. Pull some cleanup functions before rdt_get_tree() in preparation for a new helper that can be shared between mount and unmount. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Ben Horgan <ben.horgan@arm.com> Link: https://patch.msgid.link/af10101be95679e1d69ce4efc3edf980a6cc37cc.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:38 -07:00
fs/resctrl: Fix deadlock on errors during mount rdt_get_tree() acquires rdtgroup_mutex before calling kernfs_get_tree(). If superblock setup fails inside kernfs_get_tree(), the VFS calls .kill_sb() (rdt_kill_sb()) on the same thread before kernfs_get_tree() returns. rdt_kill_sb() unconditionally attempts to acquire rdtgroup_mutex and deadlock occurs. Since mount failure resulting from kernfs_get_tree() already calls the resctrl fs unmount handler (rdt_kill_sb()) let both call the same helper to make it clear both paths perform the same cleanup. Call kernfs_get_tree() outside of locks. If kernfs_get_tree() fails and ctx->kfc.new_sb_created is set, then rdt_kill_sb() has already been called and no further cleanup is needed. kernfs_get_tree() may set ctx->kfc.new_sb_created and then fail to obtain an inode for the new kn, causing the rdt_kill_sb() path to run with one fewer reference than required for the root to remain accessible in kernfs_kill_sb(). Add an extra hold on rdtgroup_default.kn to defend against this scenario and ensure the root can be dereferenced safely from kernfs_kill_sb(). Dropping locks before kernfs_get_tree() creates a window where CPU hotplug callbacks can race with the mount operation. Specifically, an online event observing resctrl_mounted == true could concurrently append directories to the unactivated kernfs tree, allocate mon_data structures, and arm background workers. This concurrency is safe because the mount has not yet returned to the VFS, meaning userspace cannot interact with these transient files. If kernfs_get_tree() subsequently fails, the standard resctrl_unmount() teardown safely manages the concurrent modifications: any dynamically generated kernfs nodes are removed, and the associated memory is freed. Any background workers spawned by the hotplug event will naturally exit without re-arming when they acquire rdtgroup_mutex and observe resctrl_mounted == false. Fixes: 5ff193fbde20 ("x86/intel_rdt: Add basic resctrl filesystem support") Closes: https://sashiko.dev/#/patchset/20260429184858.36423-1-tony.luck%40intel.com [1] Reported-by: Sashiko <sashiko-bot@kernel.org> Co-developed-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Ben Horgan <ben.horgan@arm.com> Reviewed-by: Chen Yu <yu.c.chen@intel.com> Link: https://patch.msgid.link/fe701825d7f538a6bbac6732230004050300c93e.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:39 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Fix deadlock on errors during mount rdt_get_tree() acquires rdtgroup_mutex before calling kernfs_get_tree(). If superblock setup fails inside kernfs_get_tree(), the VFS calls .kill_sb() (rdt_kill_sb()) on the same thread before kernfs_get_tree() returns. rdt_kill_sb() unconditionally attempts to acquire rdtgroup_mutex and deadlock occurs. Since mount failure resulting from kernfs_get_tree() already calls the resctrl fs unmount handler (rdt_kill_sb()) let both call the same helper to make it clear both paths perform the same cleanup. Call kernfs_get_tree() outside of locks. If kernfs_get_tree() fails and ctx->kfc.new_sb_created is set, then rdt_kill_sb() has already been called and no further cleanup is needed. kernfs_get_tree() may set ctx->kfc.new_sb_created and then fail to obtain an inode for the new kn, causing the rdt_kill_sb() path to run with one fewer reference than required for the root to remain accessible in kernfs_kill_sb(). Add an extra hold on rdtgroup_default.kn to defend against this scenario and ensure the root can be dereferenced safely from kernfs_kill_sb(). Dropping locks before kernfs_get_tree() creates a window where CPU hotplug callbacks can race with the mount operation. Specifically, an online event observing resctrl_mounted == true could concurrently append directories to the unactivated kernfs tree, allocate mon_data structures, and arm background workers. This concurrency is safe because the mount has not yet returned to the VFS, meaning userspace cannot interact with these transient files. If kernfs_get_tree() subsequently fails, the standard resctrl_unmount() teardown safely manages the concurrent modifications: any dynamically generated kernfs nodes are removed, and the associated memory is freed. Any background workers spawned by the hotplug event will naturally exit without re-arming when they acquire rdtgroup_mutex and observe resctrl_mounted == false. Fixes: 5ff193fbde20 ("x86/intel_rdt: Add basic resctrl filesystem support") Closes: https://sashiko.dev/#/patchset/20260429184858.36423-1-tony.luck%40intel.com [1] Reported-by: Sashiko <sashiko-bot@kernel.org> Co-developed-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Ben Horgan <ben.horgan@arm.com> Reviewed-by: Chen Yu <yu.c.chen@intel.com> Link: https://patch.msgid.link/fe701825d7f538a6bbac6732230004050300c93e.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:39 -07:00
x86,fs/resctrl: Rename struct rdt_mon_domain and rdt_hw_mon_domain The upcoming telemetry event monitoring is not tied to the L3 resource and will have a new domain structure. Rename the L3 resource specific domain data structures to include "l3_" in their names to avoid confusion between the different resource specific domain structures: rdt_mon_domain -> rdt_l3_mon_domain rdt_hw_mon_domain -> rdt_hw_l3_mon_domain No functional change. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:55 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Add an architectural hook called for first mount Enumeration of Intel telemetry events is an asynchronous process involving several mutually dependent drivers added as auxiliary devices during the device_initcall() phase of Linux boot. The process finishes after the probe functions of these drivers completes. But this happens after resctrl_arch_late_init() is executed. Tracing the enumeration process shows that it does complete a full seven seconds before the earliest possible mount of the resctrl file system (when included in /etc/fstab for automatic mount by systemd). Add a hook for use by telemetry event enumeration and initialization and run it once at the beginning of resctrl mount without any locks held. The architecture is responsible for any required locking. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/20260105191711.GBaVwON5nZn-uO6Sqg@fat_crate.local
2026-01-08 09:42:25 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Fix use-after-free during unmount During unmount or failure teardown all mon_data structures that contain monitoring event file private data are freed after which kernfs nodes are removed. However, the RDT_DELETED flag is never set for the statically allocated default resource group. A concurrent reader of an event file associated with the default resource group may, after dropping kernfs active protection, block on rdtgroup_mutex while unmount proceeds to free the file private data and destroy the kernfs node without waiting for the reader. When the mutex is released, the reader wakes up, observes that RDT_DELETED is not set for the default group, and dereferences the already-freed file private data. The scenario can be depicted as follows: CPU0 CPU1 /* * Default resource group's * monitoring data accessible via * kernfs file with kernfs_node::priv * pointing to a struct mon_data. * User opens the file for reading. */ rdtgroup_mondata_show() /* arch encounters fatal error */ rdtgroup_kn_lock_live() resctrl_exit() atomic_inc(&rdtgroup_default.waitcount) cpus_read_lock() kernfs_break_active_protection(kn) mutex_lock(&rdtgroup_mutex) cpus_read_lock() resctrl_fs_teardown() mutex_lock(&rdtgroup_mutex) rmdir_all_sub() mon_put_kn_priv() /* Delete all mon_data structures */ rdtgroup_destroy_root() kernfs_destroy_root() rdtgroup_default.kn = NULL mutex_unlock(&rdtgroup_mutex) /* * rdtgroup_default.flags is empty so * rdtgroup_kn_lock_live() returns * &rdtgroup_default */ md = of->kn->priv; /* md points to freed mon_data */ Set RDT_DELETED for the default group unconditionally since the flag does not lead to the freeing of this statically allocated group. Do not allow a new resctrl mount if there are any waiters on default group of previous mount. A new mount will re-initialize the default group that would appear to waiters from previous mount as though the default group is accessible causing them to access the mon_data structures from the previous mount that have been removed. Fixes: 2a6566038544 ("x86/resctrl: Expand the width of domid by replacing mon_data_bits") Closes: https://sashiko.dev/#/patchset/20260508182143.14592-1-tony.luck%40intel.com?part=2 [1] Reported-by: Sashiko <sashiko-bot@kernel.org> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Chen Yu <yu.c.chen@intel.com> Cc: <stable@kernel.org> Link: https://patch.msgid.link/49a2ca3ca688f27e1a646cf90e1dc69287021127.1783377598.git.reinette.chatre@intel.com
2026-07-06 15:46:22 -07:00
fs/resctrl: Move RMID initialization to first mount L3 monitor features are enumerated during resctrl initialization and rmid_ptrs[] that tracks all RMIDs and depends on the number of supported RMIDs is allocated during this time. Telemetry monitor features are enumerated during first resctrl mount and may support a different number of RMIDs compared to L3 monitor features. Delay allocation and initialization of rmid_ptrs[] until first mount. Since the number of RMIDs cannot change on later mounts, keep the same set of rmid_ptrs[] until resctrl_exit(). This is required because the limbo handler keeps running after resctrl is unmounted and needs to access rmid_ptrs[] as it keeps tracking busy RMIDs after unmount. Rename routines to match what they now do: dom_data_init() -> setup_rmid_lru_list() dom_data_exit() -> free_rmid_lru_list() Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:21:15 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Optimize code in rdt_get_tree() schemata_list_destroy() has to be called if schemata_list_create() fails. rdt_get_tree() calls schemata_list_destroy() in two different ways: directly if schemata_list_create() itself fails and on the exit path via the out_schemata_free goto label. Remove schemata_list_destroy() call on schemata_list_create() failure. Use existing out_schemata_free goto label instead. Signed-off-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: James Morse <james.morse@arm.com> Reviewed-by: Koba Ko <kobak@nvidia.com> Link: https://lore.kernel.org/20250623075051.3610592-1-tan.shaopeng@jp.fujitsu.com
2025-06-23 16:50:50 +09:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Auto assign counters on mkdir and clean up on group removal Resctrl provides a user-configurable option mbm_assign_on_mkdir that determines if a counter will automatically be assigned to an RMID, event pair when its associated monitor group is created via mkdir. Enable mbm_assign_on_mkdir by default to automatically assign counters to the two default events (MBM total and MBM local) of a new monitoring group created via mkdir. This maintains backward compatibility with original resctrl support for these two events. Unassign and free counters belonging to a monitoring group when the group is deleted. Monitor group creation does not fail if a counter cannot be assigned to one or both events. There may be limited counters and users have the flexibility to modify counter assignments at a later time. Log the error message "Failed to allocate counter for <event> in domain <id>" in /sys/fs/resctrl/info/last_cmd_status when a new monitoring group is created but counter assignment failed. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:26 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Document safe RCU list traversal rdt_resource::ctrl_domains and rdt_resource::mon_domains are RCU lists with entries added and removed by architecture from CPU hotplug callbacks that are run with cpus_write_lock() held. These lists can be traversed safely from resctrl fs by either holding cpus_read_lock() or relying on an RCU read-side critical section. resctrl fs traversals of rdt_resource::ctrl_domains and rdt_resource::mon_domains are done using list_for_each_entry() with cpus_read_lock() held. Similarly, x86 architecture callbacks use list_for_each_entry() expecting that resctrl fs makes the call with cpus_read_lock() held. Inconsistently, a lockdep_assert_cpus_held() precedes the list_for_each_entry() call with varying distance to document this safe RCU list traversal. In preparation for an upcoming traversal of rdt_resource::ctrl_domains that needs to be done from RCU read-side critical section there is a requirement for developers to always know exactly in which context the list is being traversed. Replace the list_for_each_entry() traversals of RCU list with list_for_each_entry_rcu() to document that an RCU list is being traversed while making use of the built-in lockdep expression that additionally documents that it is cpus_read_lock() that enables the list to be traversed from non-RCU protection. Only revert to documenting the safety of traversal using a comment when lockdep does not have needed visibility in functions called via smp_call*(). The lockdep expression within list_for_each_entry_rcu() depends on RCU_EXPERT that is not set in a typical debug kernel so keep the existing lockdep_assert_cpus_held() that is active with CONFIG_LOCKDEP=y found in typical debug kernel. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://patch.msgid.link/d9373f8da8ffde667740e186ffc96ab69628ac9a.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:37 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Fix deadlock on errors during mount rdt_get_tree() acquires rdtgroup_mutex before calling kernfs_get_tree(). If superblock setup fails inside kernfs_get_tree(), the VFS calls .kill_sb() (rdt_kill_sb()) on the same thread before kernfs_get_tree() returns. rdt_kill_sb() unconditionally attempts to acquire rdtgroup_mutex and deadlock occurs. Since mount failure resulting from kernfs_get_tree() already calls the resctrl fs unmount handler (rdt_kill_sb()) let both call the same helper to make it clear both paths perform the same cleanup. Call kernfs_get_tree() outside of locks. If kernfs_get_tree() fails and ctx->kfc.new_sb_created is set, then rdt_kill_sb() has already been called and no further cleanup is needed. kernfs_get_tree() may set ctx->kfc.new_sb_created and then fail to obtain an inode for the new kn, causing the rdt_kill_sb() path to run with one fewer reference than required for the root to remain accessible in kernfs_kill_sb(). Add an extra hold on rdtgroup_default.kn to defend against this scenario and ensure the root can be dereferenced safely from kernfs_kill_sb(). Dropping locks before kernfs_get_tree() creates a window where CPU hotplug callbacks can race with the mount operation. Specifically, an online event observing resctrl_mounted == true could concurrently append directories to the unactivated kernfs tree, allocate mon_data structures, and arm background workers. This concurrency is safe because the mount has not yet returned to the VFS, meaning userspace cannot interact with these transient files. If kernfs_get_tree() subsequently fails, the standard resctrl_unmount() teardown safely manages the concurrent modifications: any dynamically generated kernfs nodes are removed, and the associated memory is freed. Any background workers spawned by the hotplug event will naturally exit without re-arming when they acquire rdtgroup_mutex and observe resctrl_mounted == false. Fixes: 5ff193fbde20 ("x86/intel_rdt: Add basic resctrl filesystem support") Closes: https://sashiko.dev/#/patchset/20260429184858.36423-1-tony.luck%40intel.com [1] Reported-by: Sashiko <sashiko-bot@kernel.org> Co-developed-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Ben Horgan <ben.horgan@arm.com> Reviewed-by: Chen Yu <yu.c.chen@intel.com> Link: https://patch.msgid.link/fe701825d7f538a6bbac6732230004050300c93e.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:39 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Auto assign counters on mkdir and clean up on group removal Resctrl provides a user-configurable option mbm_assign_on_mkdir that determines if a counter will automatically be assigned to an RMID, event pair when its associated monitor group is created via mkdir. Enable mbm_assign_on_mkdir by default to automatically assign counters to the two default events (MBM total and MBM local) of a new monitoring group created via mkdir. This maintains backward compatibility with original resctrl support for these two events. Unassign and free counters belonging to a monitoring group when the group is deleted. Monitor group creation does not fail if a counter cannot be assigned to one or both events. There may be limited counters and users have the flexibility to modify counter assignments at a later time. Log the error message "Failed to allocate counter for <event> in domain <id>" in /sys/fs/resctrl/info/last_cmd_status when a new monitoring group is created but counter assignment failed. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:26 -05:00
fs/resctrl: Free mon_data structures on rdt_get_tree() failure If mkdir_mondata_all() or a subsequent call in rdt_get_tree() fails, the mon_data structures allocated by mon_get_kn_priv() are leaked. Add mon_put_kn_priv() to the out_mongrp error path to free the mon_data structures. Fixes: 2a6566038544 ("x86/resctrl: Expand the width of domid by replacing mon_data_bits") Closes: https://lore.kernel.org/lkml/5d38c1fb-8f91-472b-8897-24b2f50c772b@intel.com/ Reported-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Chen Yu <yu.c.chen@intel.com> Reviewed-by: Ben Horgan <ben.horgan@arm.com> Cc: <stable@kernel.org> Link: https://patch.msgid.link/433623b7e3316ffd52323255d1aa4f156ad97cb1.1783377598.git.reinette.chatre@intel.com
2026-07-06 15:46:21 -07:00
fs/resctrl: Auto assign counters on mkdir and clean up on group removal Resctrl provides a user-configurable option mbm_assign_on_mkdir that determines if a counter will automatically be assigned to an RMID, event pair when its associated monitor group is created via mkdir. Enable mbm_assign_on_mkdir by default to automatically assign counters to the two default events (MBM total and MBM local) of a new monitoring group created via mkdir. This maintains backward compatibility with original resctrl support for these two events. Unassign and free counters belonging to a monitoring group when the group is deleted. Monitor group creation does not fail if a counter cannot be assigned to one or both events. There may be limited counters and users have the flexibility to modify counter assignments at a later time. Log the error message "Failed to allocate counter for <event> in domain <id>" in /sys/fs/resctrl/info/last_cmd_status when a new monitoring group is created but counter assignment failed. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:26 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Auto assign counters on mkdir and clean up on group removal Resctrl provides a user-configurable option mbm_assign_on_mkdir that determines if a counter will automatically be assigned to an RMID, event pair when its associated monitor group is created via mkdir. Enable mbm_assign_on_mkdir by default to automatically assign counters to the two default events (MBM total and MBM local) of a new monitoring group created via mkdir. This maintains backward compatibility with original resctrl support for these two events. Unassign and free counters belonging to a monitoring group when the group is deleted. Monitor group creation does not fail if a counter cannot be assigned to one or both events. There may be limited counters and users have the flexibility to modify counter assignments at a later time. Log the error message "Failed to allocate counter for <event> in domain <id>" in /sys/fs/resctrl/info/last_cmd_status when a new monitoring group is created but counter assignment failed. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:26 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Disallow the software controller when MBM counters are assignable The software controller requires that there is one MBM counter per monitor group that is assigned to the event backing the software controller, as per mba_MBps_event. When mbm_event mode is in use, it is not guaranteed that any particular event will have an assigned counter. Currently, only AMD systems support counter assignment, but the MBA delay is non-linear and so the software controller is never supported anyway. On MPAM systems, the MBA delay is linear and so the software controller could be supported. The MPAM driver, unless a need arises, will not support the 'default' mbm_assign_mode and will always use the 'mbm_event' mode for memory bandwidth monitoring. Rather than develop a way to guarantee the counter assignment requirements needed by the software controller, take the pragmatic approach. Don't allow the software controller to be used at the same time as 'mbm_event' mode. As MPAM is the only relevant architecture and it will use 'mbm_event' mode whenever there are assignable MBM counters, for simplicity's sake, don't allow the software controller when the MBM counters are assignable. Implement this by failing the mount if the user requests the software controller, the mba_MBps option, and the MBM counters are assignable. Signed-off-by: Ben Horgan <ben.horgan@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Babu Moger <babu.moger@amd.com> Tested-by: Babu Moger <babu.moger@amd.com> Link: https://lore.kernel.org/20260506082855.3694761-1-ben.horgan@arm.com
2026-05-06 09:28:51 +01:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
Convert 'alloc_obj' family to use the new default GFP_KERNEL argument This was done entirely with mindless brute force, using git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' | xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/' to convert the new alloc_obj() users that had a simple GFP_KERNEL argument to just drop that argument. Note that due to the extreme simplicity of the scripting, any slightly more complex cases spread over multiple lines would not be triggered: they definitely exist, but this covers the vast bulk of the cases, and the resulting diff is also then easier to check automatically. For the same reason the 'flex' versions will be done as a separate conversion. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2026-02-21 16:37:42 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Fix deadlock on errors during mount rdt_get_tree() acquires rdtgroup_mutex before calling kernfs_get_tree(). If superblock setup fails inside kernfs_get_tree(), the VFS calls .kill_sb() (rdt_kill_sb()) on the same thread before kernfs_get_tree() returns. rdt_kill_sb() unconditionally attempts to acquire rdtgroup_mutex and deadlock occurs. Since mount failure resulting from kernfs_get_tree() already calls the resctrl fs unmount handler (rdt_kill_sb()) let both call the same helper to make it clear both paths perform the same cleanup. Call kernfs_get_tree() outside of locks. If kernfs_get_tree() fails and ctx->kfc.new_sb_created is set, then rdt_kill_sb() has already been called and no further cleanup is needed. kernfs_get_tree() may set ctx->kfc.new_sb_created and then fail to obtain an inode for the new kn, causing the rdt_kill_sb() path to run with one fewer reference than required for the root to remain accessible in kernfs_kill_sb(). Add an extra hold on rdtgroup_default.kn to defend against this scenario and ensure the root can be dereferenced safely from kernfs_kill_sb(). Dropping locks before kernfs_get_tree() creates a window where CPU hotplug callbacks can race with the mount operation. Specifically, an online event observing resctrl_mounted == true could concurrently append directories to the unactivated kernfs tree, allocate mon_data structures, and arm background workers. This concurrency is safe because the mount has not yet returned to the VFS, meaning userspace cannot interact with these transient files. If kernfs_get_tree() subsequently fails, the standard resctrl_unmount() teardown safely manages the concurrent modifications: any dynamically generated kernfs nodes are removed, and the associated memory is freed. Any background workers spawned by the hotplug event will naturally exit without re-arming when they acquire rdtgroup_mutex and observe resctrl_mounted == false. Fixes: 5ff193fbde20 ("x86/intel_rdt: Add basic resctrl filesystem support") Closes: https://sashiko.dev/#/patchset/20260429184858.36423-1-tony.luck%40intel.com [1] Reported-by: Sashiko <sashiko-bot@kernel.org> Co-developed-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Ben Horgan <ben.horgan@arm.com> Reviewed-by: Chen Yu <yu.c.chen@intel.com> Link: https://patch.msgid.link/fe701825d7f538a6bbac6732230004050300c93e.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:39 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Refactor rmdir_mondata_subdir_allrdtgrp() Clearing a monitor group's mon_data directory is complicated because of the support for Sub-NUMA Cluster (SNC) mode. Refactor the SNC case into a helper function to make it easier to add support for a new telemetry resource. Suggested-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:21:09 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Refactor rmdir_mondata_subdir_allrdtgrp() Clearing a monitor group's mon_data directory is complicated because of the support for Sub-NUMA Cluster (SNC) mode. Refactor the SNC case into a helper function to make it easier to add support for a new telemetry resource. Suggested-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:21:09 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Rename struct rdt_mon_domain and rdt_hw_mon_domain The upcoming telemetry event monitoring is not tied to the L3 resource and will have a new domain structure. Rename the L3 resource specific domain data structures to include "l3_" in their names to avoid confusion between the different resource specific domain structures: rdt_mon_domain -> rdt_l3_mon_domain rdt_hw_mon_domain -> rdt_hw_l3_mon_domain No functional change. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:55 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Refactor domain create/remove using struct rdt_domain_hdr Up until now, all monitoring events were associated with the L3 resource and it made sense to use the L3 specific "struct rdt_mon_domain *" argument to functions operating on domains. Telemetry events will be tied to a new resource with its instances represented by a new domain structure that, just like struct rdt_mon_domain, starts with the generic struct rdt_domain_hdr. Prepare to support domains belonging to different resources by changing the calling convention of functions operating on domains. Pass the generic header and use that to find the domain specific structure where needed. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:52 -08:00
x86,fs/resctrl: Rename struct rdt_mon_domain and rdt_hw_mon_domain The upcoming telemetry event monitoring is not tied to the L3 resource and will have a new domain structure. Rename the L3 resource specific domain data structures to include "l3_" in their names to avoid confusion between the different resource specific domain structures: rdt_mon_domain -> rdt_l3_mon_domain rdt_hw_mon_domain -> rdt_hw_l3_mon_domain No functional change. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:55 -08:00
fs/resctrl: Refactor rmdir_mondata_subdir_allrdtgrp() Clearing a monitor group's mon_data directory is complicated because of the support for Sub-NUMA Cluster (SNC) mode. Refactor the SNC case into a helper function to make it easier to add support for a new telemetry resource. Suggested-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:21:09 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Refactor rmdir_mondata_subdir_allrdtgrp() Clearing a monitor group's mon_data directory is complicated because of the support for Sub-NUMA Cluster (SNC) mode. Refactor the SNC case into a helper function to make it easier to add support for a new telemetry resource. Suggested-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:21:09 -08:00
fs/resctrl: Refactor mkdir_mondata_subdir() Population of a monitor group's mon_data directory is unreasonably complicated because of the support for Sub-NUMA Cluster (SNC) mode. Split out the SNC code into a helper function to make it easier to add support for a new telemetry resource. Move all the duplicated code to make and set owner of domain directories into the mon_add_all_files() helper and rename to _mkdir_mondata_subdir(). Suggested-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:21:08 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Refactor mkdir_mondata_subdir() Population of a monitor group's mon_data directory is unreasonably complicated because of the support for Sub-NUMA Cluster (SNC) mode. Split out the SNC code into a helper function to make it easier to add support for a new telemetry resource. Move all the duplicated code to make and set owner of domain directories into the mon_add_all_files() helper and rename to _mkdir_mondata_subdir(). Suggested-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:21:08 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Refactor mkdir_mondata_subdir() Population of a monitor group's mon_data directory is unreasonably complicated because of the support for Sub-NUMA Cluster (SNC) mode. Split out the SNC code into a helper function to make it easier to add support for a new telemetry resource. Move all the duplicated code to make and set owner of domain directories into the mon_add_all_files() helper and rename to _mkdir_mondata_subdir(). Suggested-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:21:08 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Refactor mkdir_mondata_subdir() Population of a monitor group's mon_data directory is unreasonably complicated because of the support for Sub-NUMA Cluster (SNC) mode. Split out the SNC code into a helper function to make it easier to add support for a new telemetry resource. Move all the duplicated code to make and set owner of domain directories into the mon_add_all_files() helper and rename to _mkdir_mondata_subdir(). Suggested-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:21:08 -08:00
x86,fs/resctrl: Refactor domain create/remove using struct rdt_domain_hdr Up until now, all monitoring events were associated with the L3 resource and it made sense to use the L3 specific "struct rdt_mon_domain *" argument to functions operating on domains. Telemetry events will be tied to a new resource with its instances represented by a new domain structure that, just like struct rdt_mon_domain, starts with the generic struct rdt_domain_hdr. Prepare to support domains belonging to different resources by changing the calling convention of functions operating on domains. Pass the generic header and use that to find the domain specific structure where needed. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:52 -08:00
x86,fs/resctrl: Consolidate monitor event descriptions There are currently only three monitor events, all associated with the RDT_RESOURCE_L3 resource. Growing support for additional events will be easier with some restructuring to have a single point in file system code where all attributes of all events are defined. Place all event descriptions into an array mon_event_all[]. Doing this has the beneficial side effect of removing the need for rdt_resource::evt_list. Add resctrl_event_id::QOS_FIRST_EVENT for a lower bound on range checks for event ids and as the starting index to scan mon_event_all[]. Drop the code that builds evt_list and change the two places where the list is scanned to scan mon_event_all[] instead using a new helper macro for_each_mon_event(). Architecture code now informs file system code which events are available with resctrl_enable_mon_event(). Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:00 -05:00
fs/resctrl: Refactor mkdir_mondata_subdir() Population of a monitor group's mon_data directory is unreasonably complicated because of the support for Sub-NUMA Cluster (SNC) mode. Split out the SNC code into a helper function to make it easier to add support for a new telemetry resource. Move all the duplicated code to make and set owner of domain directories into the mon_add_all_files() helper and rename to _mkdir_mondata_subdir(). Suggested-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:21:08 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Refactor mkdir_mondata_subdir() Population of a monitor group's mon_data directory is unreasonably complicated because of the support for Sub-NUMA Cluster (SNC) mode. Split out the SNC code into a helper function to make it easier to add support for a new telemetry resource. Move all the duplicated code to make and set owner of domain directories into the mon_add_all_files() helper and rename to _mkdir_mondata_subdir(). Suggested-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:21:08 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Refactor mkdir_mondata_subdir() Population of a monitor group's mon_data directory is unreasonably complicated because of the support for Sub-NUMA Cluster (SNC) mode. Split out the SNC code into a helper function to make it easier to add support for a new telemetry resource. Move all the duplicated code to make and set owner of domain directories into the mon_add_all_files() helper and rename to _mkdir_mondata_subdir(). Suggested-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:21:08 -08:00
fs/resctrl: Make event details accessible to functions when reading events Reading monitoring event data from MMIO requires more context than the event id to be able to read the correct memory location. struct mon_evt is the appropriate place for this event specific context. Prepare for addition of extra fields to struct mon_evt by changing the calling conventions to pass a pointer to the mon_evt structure instead of just the event id. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:57 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Refactor mkdir_mondata_subdir() Population of a monitor group's mon_data directory is unreasonably complicated because of the support for Sub-NUMA Cluster (SNC) mode. Split out the SNC code into a helper function to make it easier to add support for a new telemetry resource. Move all the duplicated code to make and set owner of domain directories into the mon_add_all_files() helper and rename to _mkdir_mondata_subdir(). Suggested-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:21:08 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Refactor mkdir_mondata_subdir() Population of a monitor group's mon_data directory is unreasonably complicated because of the support for Sub-NUMA Cluster (SNC) mode. Split out the SNC code into a helper function to make it easier to add support for a new telemetry resource. Move all the duplicated code to make and set owner of domain directories into the mon_add_all_files() helper and rename to _mkdir_mondata_subdir(). Suggested-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:21:08 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Refactor mkdir_mondata_subdir() Population of a monitor group's mon_data directory is unreasonably complicated because of the support for Sub-NUMA Cluster (SNC) mode. Split out the SNC code into a helper function to make it easier to add support for a new telemetry resource. Move all the duplicated code to make and set owner of domain directories into the mon_add_all_files() helper and rename to _mkdir_mondata_subdir(). Suggested-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:21:08 -08:00
x86,fs/resctrl: Rename struct rdt_mon_domain and rdt_hw_mon_domain The upcoming telemetry event monitoring is not tied to the L3 resource and will have a new domain structure. Rename the L3 resource specific domain data structures to include "l3_" in their names to avoid confusion between the different resource specific domain structures: rdt_mon_domain -> rdt_l3_mon_domain rdt_hw_mon_domain -> rdt_hw_l3_mon_domain No functional change. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:55 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Refactor domain create/remove using struct rdt_domain_hdr Up until now, all monitoring events were associated with the L3 resource and it made sense to use the L3 specific "struct rdt_mon_domain *" argument to functions operating on domains. Telemetry events will be tied to a new resource with its instances represented by a new domain structure that, just like struct rdt_mon_domain, starts with the generic struct rdt_domain_hdr. Prepare to support domains belonging to different resources by changing the calling convention of functions operating on domains. Pass the generic header and use that to find the domain specific structure where needed. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:52 -08:00
x86,fs/resctrl: Rename struct rdt_mon_domain and rdt_hw_mon_domain The upcoming telemetry event monitoring is not tied to the L3 resource and will have a new domain structure. Rename the L3 resource specific domain data structures to include "l3_" in their names to avoid confusion between the different resource specific domain structures: rdt_mon_domain -> rdt_l3_mon_domain rdt_hw_mon_domain -> rdt_hw_l3_mon_domain No functional change. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:55 -08:00
fs/resctrl: Refactor mkdir_mondata_subdir() Population of a monitor group's mon_data directory is unreasonably complicated because of the support for Sub-NUMA Cluster (SNC) mode. Split out the SNC code into a helper function to make it easier to add support for a new telemetry resource. Move all the duplicated code to make and set owner of domain directories into the mon_add_all_files() helper and rename to _mkdir_mondata_subdir(). Suggested-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:21:08 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Refactor mkdir_mondata_subdir() Population of a monitor group's mon_data directory is unreasonably complicated because of the support for Sub-NUMA Cluster (SNC) mode. Split out the SNC code into a helper function to make it easier to add support for a new telemetry resource. Move all the duplicated code to make and set owner of domain directories into the mon_add_all_files() helper and rename to _mkdir_mondata_subdir(). Suggested-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:21:08 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Refactor mkdir_mondata_subdir() Population of a monitor group's mon_data directory is unreasonably complicated because of the support for Sub-NUMA Cluster (SNC) mode. Split out the SNC code into a helper function to make it easier to add support for a new telemetry resource. Move all the duplicated code to make and set owner of domain directories into the mon_add_all_files() helper and rename to _mkdir_mondata_subdir(). Suggested-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:21:08 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Refactor mkdir_mondata_subdir() Population of a monitor group's mon_data directory is unreasonably complicated because of the support for Sub-NUMA Cluster (SNC) mode. Split out the SNC code into a helper function to make it easier to add support for a new telemetry resource. Move all the duplicated code to make and set owner of domain directories into the mon_add_all_files() helper and rename to _mkdir_mondata_subdir(). Suggested-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:21:08 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Refactor mkdir_mondata_subdir() Population of a monitor group's mon_data directory is unreasonably complicated because of the support for Sub-NUMA Cluster (SNC) mode. Split out the SNC code into a helper function to make it easier to add support for a new telemetry resource. Move all the duplicated code to make and set owner of domain directories into the mon_add_all_files() helper and rename to _mkdir_mondata_subdir(). Suggested-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:21:08 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Refactor domain create/remove using struct rdt_domain_hdr Up until now, all monitoring events were associated with the L3 resource and it made sense to use the L3 specific "struct rdt_mon_domain *" argument to functions operating on domains. Telemetry events will be tied to a new resource with its instances represented by a new domain structure that, just like struct rdt_mon_domain, starts with the generic struct rdt_domain_hdr. Prepare to support domains belonging to different resources by changing the calling convention of functions operating on domains. Pass the generic header and use that to find the domain specific structure where needed. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:52 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Refactor domain create/remove using struct rdt_domain_hdr Up until now, all monitoring events were associated with the L3 resource and it made sense to use the L3 specific "struct rdt_mon_domain *" argument to functions operating on domains. Telemetry events will be tied to a new resource with its instances represented by a new domain structure that, just like struct rdt_mon_domain, starts with the generic struct rdt_domain_hdr. Prepare to support domains belonging to different resources by changing the calling convention of functions operating on domains. Pass the generic header and use that to find the domain specific structure where needed. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:52 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Refactor domain create/remove using struct rdt_domain_hdr Up until now, all monitoring events were associated with the L3 resource and it made sense to use the L3 specific "struct rdt_mon_domain *" argument to functions operating on domains. Telemetry events will be tied to a new resource with its instances represented by a new domain structure that, just like struct rdt_mon_domain, starts with the generic struct rdt_domain_hdr. Prepare to support domains belonging to different resources by changing the calling convention of functions operating on domains. Pass the generic header and use that to find the domain specific structure where needed. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:52 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Refactor domain create/remove using struct rdt_domain_hdr Up until now, all monitoring events were associated with the L3 resource and it made sense to use the L3 specific "struct rdt_mon_domain *" argument to functions operating on domains. Telemetry events will be tied to a new resource with its instances represented by a new domain structure that, just like struct rdt_mon_domain, starts with the generic struct rdt_domain_hdr. Prepare to support domains belonging to different resources by changing the calling convention of functions operating on domains. Pass the generic header and use that to find the domain specific structure where needed. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:52 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Document safe RCU list traversal rdt_resource::ctrl_domains and rdt_resource::mon_domains are RCU lists with entries added and removed by architecture from CPU hotplug callbacks that are run with cpus_write_lock() held. These lists can be traversed safely from resctrl fs by either holding cpus_read_lock() or relying on an RCU read-side critical section. resctrl fs traversals of rdt_resource::ctrl_domains and rdt_resource::mon_domains are done using list_for_each_entry() with cpus_read_lock() held. Similarly, x86 architecture callbacks use list_for_each_entry() expecting that resctrl fs makes the call with cpus_read_lock() held. Inconsistently, a lockdep_assert_cpus_held() precedes the list_for_each_entry() call with varying distance to document this safe RCU list traversal. In preparation for an upcoming traversal of rdt_resource::ctrl_domains that needs to be done from RCU read-side critical section there is a requirement for developers to always know exactly in which context the list is being traversed. Replace the list_for_each_entry() traversals of RCU list with list_for_each_entry_rcu() to document that an RCU list is being traversed while making use of the built-in lockdep expression that additionally documents that it is cpus_read_lock() that enables the list to be traversed from non-RCU protection. Only revert to documenting the safety of traversal using a comment when lockdep does not have needed visibility in functions called via smp_call*(). The lockdep expression within list_for_each_entry_rcu() depends on RCU_EXPERT that is not set in a typical debug kernel so keep the existing lockdep_assert_cpus_held() that is active with CONFIG_LOCKDEP=y found in typical debug kernel. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://patch.msgid.link/d9373f8da8ffde667740e186ffc96ab69628ac9a.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:37 -07:00
x86,fs/resctrl: Refactor domain create/remove using struct rdt_domain_hdr Up until now, all monitoring events were associated with the L3 resource and it made sense to use the L3 specific "struct rdt_mon_domain *" argument to functions operating on domains. Telemetry events will be tied to a new resource with its instances represented by a new domain structure that, just like struct rdt_mon_domain, starts with the generic struct rdt_domain_hdr. Prepare to support domains belonging to different resources by changing the calling convention of functions operating on domains. Pass the generic header and use that to find the domain specific structure where needed. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:52 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Add missing return value descriptions Using the stricter "./tools/docs/kernel-doc -Wall -v" to verify proper formatting of documentation comments includes warnings related to return markup on functions that are omitted during the default verification checks. This stricter verification reports a couple of missing return descriptions in resctrl: Warning: .../fs/resctrl/rdtgroup.c:1536 No description found for return value of 'rdtgroup_cbm_to_size' Warning: .../fs/resctrl/rdtgroup.c:3131 No description found for return value of 'mon_get_kn_priv' Warning: .../fs/resctrl/rdtgroup.c:3523 No description found for return value of 'cbm_ensure_valid' Warning: .../fs/resctrl/monitor.c:238 No description found for return value of 'resctrl_find_cleanest_closid' Add the missing return descriptions. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://patch.msgid.link/1c50b9f7c73251c007133590986f127e1af57780.1775576382.git.reinette.chatre@intel.com
2026-04-07 09:01:59 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Consider sparse masks when initializing new group's allocation A new resource group is intended to be created with sane defaults. For a cache resource this means all cache portions the new group could possibly allocate into. This includes unused cache portions and shareable cache portions used by other groups and hardware. New resource group creation does not take sparse masks into account. After determining the bitmask reflecting the new group's possible allocations the bitmask is forced to be contiguous even if the system supports sparse masks. For example, a new group could by default allocate into a large portion of cache represented by 0xff0f, but it is instead created with a mask of 0xf. Do not force a contiguous allocation range if the system supports sparse masks. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://patch.msgid.link/abbbb008bc09d982d715e79d3b885c10f92c64e0.1763426240.git.reinette.chatre@intel.com
2025-11-17 16:42:45 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Consider sparse masks when initializing new group's allocation A new resource group is intended to be created with sane defaults. For a cache resource this means all cache portions the new group could possibly allocate into. This includes unused cache portions and shareable cache portions used by other groups and hardware. New resource group creation does not take sparse masks into account. After determining the bitmask reflecting the new group's possible allocations the bitmask is forced to be contiguous even if the system supports sparse masks. For example, a new group could by default allocate into a large portion of cache represented by 0xff0f, but it is instead created with a mask of 0xf. Do not force a contiguous allocation range if the system supports sparse masks. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://patch.msgid.link/abbbb008bc09d982d715e79d3b885c10f92c64e0.1763426240.git.reinette.chatre@intel.com
2025-11-17 16:42:45 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Consider sparse masks when initializing new group's allocation A new resource group is intended to be created with sane defaults. For a cache resource this means all cache portions the new group could possibly allocate into. This includes unused cache portions and shareable cache portions used by other groups and hardware. New resource group creation does not take sparse masks into account. After determining the bitmask reflecting the new group's possible allocations the bitmask is forced to be contiguous even if the system supports sparse masks. For example, a new group could by default allocate into a large portion of cache represented by 0xff0f, but it is instead created with a mask of 0xf. Do not force a contiguous allocation range if the system supports sparse masks. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://patch.msgid.link/abbbb008bc09d982d715e79d3b885c10f92c64e0.1763426240.git.reinette.chatre@intel.com
2025-11-17 16:42:45 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Add user interface to enable/disable io_alloc feature AMD's SDCIAE forces all SDCI lines to be placed into the L3 cache portions identified by the highest-supported L3_MASK_n register, where n is the maximum supported CLOSID. To support this, when io_alloc resctrl feature is enabled, reserve the highest CLOSID exclusively for I/O allocation traffic making it no longer available for general CPU cache allocation. Introduce user interface to enable/disable io_alloc feature and encourage users to enable io_alloc only when running workloads that can benefit from this functionality. On enable, initialize the io_alloc CLOSID with all usable CBMs across all the domains. Since CLOSIDs are managed by resctrl fs, it is least invasive to make "io_alloc is supported by maximum supported CLOSID" part of the initial resctrl fs support for io_alloc. Take care to minimally (only in error messages) expose this use of CLOSID for io_alloc to user space so that this is not required from other architectures that may support io_alloc differently in the future. When resctrl is mounted with "-o cdp" to enable code/data prioritization, there are two L3 resources that can support I/O allocation: L3CODE and L3DATA. From resctrl fs perspective the two resources share a CLOSID and the architecture's available CLOSID are halved to support this. The architecture's underlying CLOSID used by SDCIAE when CDP is enabled is the CLOSID associated with the CDP_CODE resource, but from resctrl's perspective there is only one CLOSID for both CDP_CODE and CDP_DATA. CDP_DATA is thus not usable for general (CPU) cache allocation nor I/O allocation. Keep the CDP_CODE and CDP_DATA I/O alloc status in sync to avoid any confusion to user space. That is, enabling io_alloc on CDP_CODE does so on CDP_DATA and vice-versa, and keep the I/O allocation CBMs of CDP_CODE and CDP_DATA in sync. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://patch.msgid.link/c7d3037795e653e22b02d8fc73ca80d9b075031c.1762995456.git.babu.moger@amd.com
2025-11-12 18:57:32 -06:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Document safe RCU list traversal rdt_resource::ctrl_domains and rdt_resource::mon_domains are RCU lists with entries added and removed by architecture from CPU hotplug callbacks that are run with cpus_write_lock() held. These lists can be traversed safely from resctrl fs by either holding cpus_read_lock() or relying on an RCU read-side critical section. resctrl fs traversals of rdt_resource::ctrl_domains and rdt_resource::mon_domains are done using list_for_each_entry() with cpus_read_lock() held. Similarly, x86 architecture callbacks use list_for_each_entry() expecting that resctrl fs makes the call with cpus_read_lock() held. Inconsistently, a lockdep_assert_cpus_held() precedes the list_for_each_entry() call with varying distance to document this safe RCU list traversal. In preparation for an upcoming traversal of rdt_resource::ctrl_domains that needs to be done from RCU read-side critical section there is a requirement for developers to always know exactly in which context the list is being traversed. Replace the list_for_each_entry() traversals of RCU list with list_for_each_entry_rcu() to document that an RCU list is being traversed while making use of the built-in lockdep expression that additionally documents that it is cpus_read_lock() that enables the list to be traversed from non-RCU protection. Only revert to documenting the safety of traversal using a comment when lockdep does not have needed visibility in functions called via smp_call*(). The lockdep expression within list_for_each_entry_rcu() depends on RCU_EXPERT that is not set in a typical debug kernel so keep the existing lockdep_assert_cpus_held() that is active with CONFIG_LOCKDEP=y found in typical debug kernel. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://patch.msgid.link/d9373f8da8ffde667740e186ffc96ab69628ac9a.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:37 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Document safe RCU list traversal rdt_resource::ctrl_domains and rdt_resource::mon_domains are RCU lists with entries added and removed by architecture from CPU hotplug callbacks that are run with cpus_write_lock() held. These lists can be traversed safely from resctrl fs by either holding cpus_read_lock() or relying on an RCU read-side critical section. resctrl fs traversals of rdt_resource::ctrl_domains and rdt_resource::mon_domains are done using list_for_each_entry() with cpus_read_lock() held. Similarly, x86 architecture callbacks use list_for_each_entry() expecting that resctrl fs makes the call with cpus_read_lock() held. Inconsistently, a lockdep_assert_cpus_held() precedes the list_for_each_entry() call with varying distance to document this safe RCU list traversal. In preparation for an upcoming traversal of rdt_resource::ctrl_domains that needs to be done from RCU read-side critical section there is a requirement for developers to always know exactly in which context the list is being traversed. Replace the list_for_each_entry() traversals of RCU list with list_for_each_entry_rcu() to document that an RCU list is being traversed while making use of the built-in lockdep expression that additionally documents that it is cpus_read_lock() that enables the list to be traversed from non-RCU protection. Only revert to documenting the safety of traversal using a comment when lockdep does not have needed visibility in functions called via smp_call*(). The lockdep expression within list_for_each_entry_rcu() depends on RCU_EXPERT that is not set in a typical debug kernel so keep the existing lockdep_assert_cpus_held() that is active with CONFIG_LOCKDEP=y found in typical debug kernel. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://patch.msgid.link/d9373f8da8ffde667740e186ffc96ab69628ac9a.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:37 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Auto assign counters on mkdir and clean up on group removal Resctrl provides a user-configurable option mbm_assign_on_mkdir that determines if a counter will automatically be assigned to an RMID, event pair when its associated monitor group is created via mkdir. Enable mbm_assign_on_mkdir by default to automatically assign counters to the two default events (MBM total and MBM local) of a new monitoring group created via mkdir. This maintains backward compatibility with original resctrl support for these two events. Unassign and free counters belonging to a monitoring group when the group is deleted. Monitor group creation does not fail if a counter cannot be assigned to one or both events. There may be limited counters and users have the flexibility to modify counter assignments at a later time. Log the error message "Failed to allocate counter for <event> in domain <id>" in /sys/fs/resctrl/info/last_cmd_status when a new monitoring group is created but counter assignment failed. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:26 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Auto assign counters on mkdir and clean up on group removal Resctrl provides a user-configurable option mbm_assign_on_mkdir that determines if a counter will automatically be assigned to an RMID, event pair when its associated monitor group is created via mkdir. Enable mbm_assign_on_mkdir by default to automatically assign counters to the two default events (MBM total and MBM local) of a new monitoring group created via mkdir. This maintains backward compatibility with original resctrl support for these two events. Unassign and free counters belonging to a monitoring group when the group is deleted. Monitor group creation does not fail if a counter cannot be assigned to one or both events. There may be limited counters and users have the flexibility to modify counter assignments at a later time. Log the error message "Failed to allocate counter for <event> in domain <id>" in /sys/fs/resctrl/info/last_cmd_status when a new monitoring group is created but counter assignment failed. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:26 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Auto assign counters on mkdir and clean up on group removal Resctrl provides a user-configurable option mbm_assign_on_mkdir that determines if a counter will automatically be assigned to an RMID, event pair when its associated monitor group is created via mkdir. Enable mbm_assign_on_mkdir by default to automatically assign counters to the two default events (MBM total and MBM local) of a new monitoring group created via mkdir. This maintains backward compatibility with original resctrl support for these two events. Unassign and free counters belonging to a monitoring group when the group is deleted. Monitor group creation does not fail if a counter cannot be assigned to one or both events. There may be limited counters and users have the flexibility to modify counter assignments at a later time. Log the error message "Failed to allocate counter for <event> in domain <id>" in /sys/fs/resctrl/info/last_cmd_status when a new monitoring group is created but counter assignment failed. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:26 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Auto assign counters on mkdir and clean up on group removal Resctrl provides a user-configurable option mbm_assign_on_mkdir that determines if a counter will automatically be assigned to an RMID, event pair when its associated monitor group is created via mkdir. Enable mbm_assign_on_mkdir by default to automatically assign counters to the two default events (MBM total and MBM local) of a new monitoring group created via mkdir. This maintains backward compatibility with original resctrl support for these two events. Unassign and free counters belonging to a monitoring group when the group is deleted. Monitor group creation does not fail if a counter cannot be assigned to one or both events. There may be limited counters and users have the flexibility to modify counter assignments at a later time. Log the error message "Failed to allocate counter for <event> in domain <id>" in /sys/fs/resctrl/info/last_cmd_status when a new monitoring group is created but counter assignment failed. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:26 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
Convert 'alloc_obj' family to use the new default GFP_KERNEL argument This was done entirely with mindless brute force, using git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' | xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/' to convert the new alloc_obj() users that had a simple GFP_KERNEL argument to just drop that argument. Note that due to the extreme simplicity of the scripting, any slightly more complex cases spread over multiple lines would not be triggered: they definitely exist, but this covers the vast bulk of the cases, and the resulting diff is also then easier to check automatically. For the same reason the 'flex' versions will be done as a separate conversion. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2026-02-21 16:37:42 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Auto assign counters on mkdir and clean up on group removal Resctrl provides a user-configurable option mbm_assign_on_mkdir that determines if a counter will automatically be assigned to an RMID, event pair when its associated monitor group is created via mkdir. Enable mbm_assign_on_mkdir by default to automatically assign counters to the two default events (MBM total and MBM local) of a new monitoring group created via mkdir. This maintains backward compatibility with original resctrl support for these two events. Unassign and free counters belonging to a monitoring group when the group is deleted. Monitor group creation does not fail if a counter cannot be assigned to one or both events. There may be limited counters and users have the flexibility to modify counter assignments at a later time. Log the error message "Failed to allocate counter for <event> in domain <id>" in /sys/fs/resctrl/info/last_cmd_status when a new monitoring group is created but counter assignment failed. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:26 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Auto assign counters on mkdir and clean up on group removal Resctrl provides a user-configurable option mbm_assign_on_mkdir that determines if a counter will automatically be assigned to an RMID, event pair when its associated monitor group is created via mkdir. Enable mbm_assign_on_mkdir by default to automatically assign counters to the two default events (MBM total and MBM local) of a new monitoring group created via mkdir. This maintains backward compatibility with original resctrl support for these two events. Unassign and free counters belonging to a monitoring group when the group is deleted. Monitor group creation does not fail if a counter cannot be assigned to one or both events. There may be limited counters and users have the flexibility to modify counter assignments at a later time. Log the error message "Failed to allocate counter for <event> in domain <id>" in /sys/fs/resctrl/info/last_cmd_status when a new monitoring group is created but counter assignment failed. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:26 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Fix use-after-free during unmount During unmount or failure teardown all mon_data structures that contain monitoring event file private data are freed after which kernfs nodes are removed. However, the RDT_DELETED flag is never set for the statically allocated default resource group. A concurrent reader of an event file associated with the default resource group may, after dropping kernfs active protection, block on rdtgroup_mutex while unmount proceeds to free the file private data and destroy the kernfs node without waiting for the reader. When the mutex is released, the reader wakes up, observes that RDT_DELETED is not set for the default group, and dereferences the already-freed file private data. The scenario can be depicted as follows: CPU0 CPU1 /* * Default resource group's * monitoring data accessible via * kernfs file with kernfs_node::priv * pointing to a struct mon_data. * User opens the file for reading. */ rdtgroup_mondata_show() /* arch encounters fatal error */ rdtgroup_kn_lock_live() resctrl_exit() atomic_inc(&rdtgroup_default.waitcount) cpus_read_lock() kernfs_break_active_protection(kn) mutex_lock(&rdtgroup_mutex) cpus_read_lock() resctrl_fs_teardown() mutex_lock(&rdtgroup_mutex) rmdir_all_sub() mon_put_kn_priv() /* Delete all mon_data structures */ rdtgroup_destroy_root() kernfs_destroy_root() rdtgroup_default.kn = NULL mutex_unlock(&rdtgroup_mutex) /* * rdtgroup_default.flags is empty so * rdtgroup_kn_lock_live() returns * &rdtgroup_default */ md = of->kn->priv; /* md points to freed mon_data */ Set RDT_DELETED for the default group unconditionally since the flag does not lead to the freeing of this statically allocated group. Do not allow a new resctrl mount if there are any waiters on default group of previous mount. A new mount will re-initialize the default group that would appear to waiters from previous mount as though the default group is accessible causing them to access the mon_data structures from the previous mount that have been removed. Fixes: 2a6566038544 ("x86/resctrl: Expand the width of domid by replacing mon_data_bits") Closes: https://sashiko.dev/#/patchset/20260508182143.14592-1-tony.luck%40intel.com?part=2 [1] Reported-by: Sashiko <sashiko-bot@kernel.org> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Chen Yu <yu.c.chen@intel.com> Cc: <stable@kernel.org> Link: https://patch.msgid.link/49a2ca3ca688f27e1a646cf90e1dc69287021127.1783377598.git.reinette.chatre@intel.com
2026-07-06 15:46:22 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Rename some L3 specific functions With the arrival of monitor events tied to new domains associated with a different resource it would be clearer if the L3 resource specific functions are more accurately named. Rename three groups of functions: Functions that allocate/free architecture per-RMID MBM state information: arch_domain_mbm_alloc() -> l3_mon_domain_mbm_alloc() mon_domain_free() -> l3_mon_domain_free() Functions that allocate/free filesystem per-RMID MBM state information: domain_setup_mon_state() -> domain_setup_l3_mon_state() domain_destroy_mon_state() -> domain_destroy_l3_mon_state() Initialization/exit: rdt_get_mon_l3_config() -> rdt_get_l3_mon_config() resctrl_mon_resource_init() -> resctrl_l3_mon_resource_init() resctrl_mon_resource_exit() -> resctrl_l3_mon_resource_exit() Ensure kernel-doc descriptions of these functions' return values are present and correctly formatted. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:56 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Prepare for more monitor events There's a rule in computer programming that objects appear zero, once, or many times. So code accordingly. There are two MBM events and resctrl is coded with a lot of if (local) do one thing if (total) do a different thing Change the rdt_mon_domain and rdt_hw_mon_domain structures to hold arrays of pointers to per event data instead of explicit fields for total and local bandwidth. Simplify by coding for many events using loops on which are enabled. Move resctrl_is_mbm_event() to <linux/resctrl.h> so it can be used more widely. Also provide a for_each_mbm_event_id() helper macro. Cleanup variable names in functions touched to consistently use "eventid" for those with type enum resctrl_event_id. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:03 -05:00
fs/resctrl: Introduce mbm_cntr_cfg to track assignable counters per domain The "mbm_event" counter assignment mode allows users to assign a hardware counter to an RMID, event pair and monitor bandwidth usage as long as it is assigned. The hardware continues to track the assigned counter until it is explicitly unassigned by the user. Counters are assigned/unassigned at monitoring domain level. Manage a monitoring domain's hardware counters using a per monitoring domain array of struct mbm_cntr_cfg that is indexed by the hardware counter ID. A hardware counter's configuration contains the MBM event ID and points to the monitoring group that it is assigned to, with a NULL pointer meaning that the hardware counter is available for assignment. There is no direct way to determine which hardware counters are assigned to a particular monitoring group. Check every entry of every hardware counter configuration array in every monitoring domain to query which MBM events of a monitoring group is tracked by hardware. Such queries are acceptable because of a very small number of assignable counters (32 to 64). Suggested-by: Peter Newman <peternewman@google.com> Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:11 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Prepare for more monitor events There's a rule in computer programming that objects appear zero, once, or many times. So code accordingly. There are two MBM events and resctrl is coded with a lot of if (local) do one thing if (total) do a different thing Change the rdt_mon_domain and rdt_hw_mon_domain structures to hold arrays of pointers to per event data instead of explicit fields for total and local bandwidth. Simplify by coding for many events using loops on which are enabled. Move resctrl_is_mbm_event() to <linux/resctrl.h> so it can be used more widely. Also provide a for_each_mbm_event_id() helper macro. Cleanup variable names in functions touched to consistently use "eventid" for those with type enum resctrl_event_id. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:03 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Fix UAF from worker threads when domains are removed The mbm_handle_overflow() and cqm_handle_limbo() workers read event counters and may sleep while doing so. They are scheduled via delayed_work embedded in struct rdt_l3_mon_domain. Architecture allocates and frees these domains from CPU hotplug callbacks under cpus_write_lock(), and the workers acquire cpus_read_lock() to keep the domain alive across their access. A use-after-free can occur when a worker is blocked waiting for cpus_read_lock() while the hotplug core holds cpus_write_lock(): the architecture frees the rdt_l3_mon_domain that contains the worker's work_struct. When the worker unblocks, the container_of() it performs on the embedded work pointer dereferences freed memory. Drop cpus_read_lock() from the workers and instead drain pending and in-flight work synchronously before the architecture can free the domain. Since architecture offlines the domain under cpus_write_lock() after it has been unlinked from the RCU list and a grace period has elapsed, no new work can be scheduled. The cancel only needs to wait out existing work. Drop rdtgroup_mutex during CPU offline around cancel_delayed_work_sync() so that a worker waiting on the mutex can complete before re-pinning the work on a different CPU. When offlining a CPU the architecture may iterate over resources in any order. For example, the MBA control domain may be offlined before or after a corresponding L3 monitor domain. Ensure that resctrl fs cancels the workers no matter what order the architecture offlines the domains. Fixes: 24247aeeabe9 ("x86/intel_rdt/cqm: Improve limbo list processing") Closes: https://sashiko.dev/#/patchset/20260429184858.36423-1-tony.luck%40intel.com # [1] Reported-by: Sashiko <sashiko-bot@kernel.org> Co-developed-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://patch.msgid.link/3f0e0752deb3421606dfc4600f0ab3a4ae098cd7.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:43 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Refactor domain create/remove using struct rdt_domain_hdr Up until now, all monitoring events were associated with the L3 resource and it made sense to use the L3 specific "struct rdt_mon_domain *" argument to functions operating on domains. Telemetry events will be tied to a new resource with its instances represented by a new domain structure that, just like struct rdt_mon_domain, starts with the generic struct rdt_domain_hdr. Prepare to support domains belonging to different resources by changing the calling convention of functions operating on domains. Pass the generic header and use that to find the domain specific structure where needed. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:52 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Rename struct rdt_mon_domain and rdt_hw_mon_domain The upcoming telemetry event monitoring is not tied to the L3 resource and will have a new domain structure. Rename the L3 resource specific domain data structures to include "l3_" in their names to avoid confusion between the different resource specific domain structures: rdt_mon_domain -> rdt_l3_mon_domain rdt_hw_mon_domain -> rdt_hw_l3_mon_domain No functional change. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:55 -08:00
x86,fs/resctrl: Refactor domain create/remove using struct rdt_domain_hdr Up until now, all monitoring events were associated with the L3 resource and it made sense to use the L3 specific "struct rdt_mon_domain *" argument to functions operating on domains. Telemetry events will be tied to a new resource with its instances represented by a new domain structure that, just like struct rdt_mon_domain, starts with the generic struct rdt_domain_hdr. Prepare to support domains belonging to different resources by changing the calling convention of functions operating on domains. Pass the generic header and use that to find the domain specific structure where needed. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:52 -08:00
fs/resctrl: Fix UAF from worker threads when domains are removed The mbm_handle_overflow() and cqm_handle_limbo() workers read event counters and may sleep while doing so. They are scheduled via delayed_work embedded in struct rdt_l3_mon_domain. Architecture allocates and frees these domains from CPU hotplug callbacks under cpus_write_lock(), and the workers acquire cpus_read_lock() to keep the domain alive across their access. A use-after-free can occur when a worker is blocked waiting for cpus_read_lock() while the hotplug core holds cpus_write_lock(): the architecture frees the rdt_l3_mon_domain that contains the worker's work_struct. When the worker unblocks, the container_of() it performs on the embedded work pointer dereferences freed memory. Drop cpus_read_lock() from the workers and instead drain pending and in-flight work synchronously before the architecture can free the domain. Since architecture offlines the domain under cpus_write_lock() after it has been unlinked from the RCU list and a grace period has elapsed, no new work can be scheduled. The cancel only needs to wait out existing work. Drop rdtgroup_mutex during CPU offline around cancel_delayed_work_sync() so that a worker waiting on the mutex can complete before re-pinning the work on a different CPU. When offlining a CPU the architecture may iterate over resources in any order. For example, the MBA control domain may be offlined before or after a corresponding L3 monitor domain. Ensure that resctrl fs cancels the workers no matter what order the architecture offlines the domains. Fixes: 24247aeeabe9 ("x86/intel_rdt/cqm: Improve limbo list processing") Closes: https://sashiko.dev/#/patchset/20260429184858.36423-1-tony.luck%40intel.com # [1] Reported-by: Sashiko <sashiko-bot@kernel.org> Co-developed-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://patch.msgid.link/3f0e0752deb3421606dfc4600f0ab3a4ae098cd7.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:43 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Refactor domain create/remove using struct rdt_domain_hdr Up until now, all monitoring events were associated with the L3 resource and it made sense to use the L3 specific "struct rdt_mon_domain *" argument to functions operating on domains. Telemetry events will be tied to a new resource with its instances represented by a new domain structure that, just like struct rdt_mon_domain, starts with the generic struct rdt_domain_hdr. Prepare to support domains belonging to different resources by changing the calling convention of functions operating on domains. Pass the generic header and use that to find the domain specific structure where needed. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:52 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Handle domain creation/deletion for RDT_RESOURCE_PERF_PKG The L3 resource has several requirements for domains. There are per-domain structures that hold the 64-bit values of counters, and elements to keep track of the overflow and limbo threads. None of these are needed for the PERF_PKG resource. The hardware counters are wide enough that they do not wrap around for decades. Define a new rdt_perf_pkg_mon_domain structure which just consists of the standard rdt_domain_hdr to keep track of domain id and CPU mask. Update resctrl_online_mon_domain() for RDT_RESOURCE_PERF_PKG. The only action needed for this resource is to create and populate domain directories if a domain is added while resctrl is mounted. Similarly resctrl_offline_mon_domain() only needs to remove domain directories. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:21:10 -08:00
x86,fs/resctrl: Replace architecture event enabled checks The resctrl file system now has complete knowledge of the status of every event. So there is no need for per-event function calls to check. Replace each of the resctrl_arch_is_{event}enabled() calls with resctrl_is_mon_event_enabled(QOS_{EVENT}). No functional change. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:01 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Rename some L3 specific functions With the arrival of monitor events tied to new domains associated with a different resource it would be clearer if the L3 resource specific functions are more accurately named. Rename three groups of functions: Functions that allocate/free architecture per-RMID MBM state information: arch_domain_mbm_alloc() -> l3_mon_domain_mbm_alloc() mon_domain_free() -> l3_mon_domain_free() Functions that allocate/free filesystem per-RMID MBM state information: domain_setup_mon_state() -> domain_setup_l3_mon_state() domain_destroy_mon_state() -> domain_destroy_l3_mon_state() Initialization/exit: rdt_get_mon_l3_config() -> rdt_get_l3_mon_config() resctrl_mon_resource_init() -> resctrl_l3_mon_resource_init() resctrl_mon_resource_exit() -> resctrl_l3_mon_resource_exit() Ensure kernel-doc descriptions of these functions' return values are present and correctly formatted. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:56 -08:00
x86,fs/resctrl: Refactor domain create/remove using struct rdt_domain_hdr Up until now, all monitoring events were associated with the L3 resource and it made sense to use the L3 specific "struct rdt_mon_domain *" argument to functions operating on domains. Telemetry events will be tied to a new resource with its instances represented by a new domain structure that, just like struct rdt_mon_domain, starts with the generic struct rdt_domain_hdr. Prepare to support domains belonging to different resources by changing the calling convention of functions operating on domains. Pass the generic header and use that to find the domain specific structure where needed. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:52 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Rename some L3 specific functions With the arrival of monitor events tied to new domains associated with a different resource it would be clearer if the L3 resource specific functions are more accurately named. Rename three groups of functions: Functions that allocate/free architecture per-RMID MBM state information: arch_domain_mbm_alloc() -> l3_mon_domain_mbm_alloc() mon_domain_free() -> l3_mon_domain_free() Functions that allocate/free filesystem per-RMID MBM state information: domain_setup_mon_state() -> domain_setup_l3_mon_state() domain_destroy_mon_state() -> domain_destroy_l3_mon_state() Initialization/exit: rdt_get_mon_l3_config() -> rdt_get_l3_mon_config() resctrl_mon_resource_init() -> resctrl_l3_mon_resource_init() resctrl_mon_resource_exit() -> resctrl_l3_mon_resource_exit() Ensure kernel-doc descriptions of these functions' return values are present and correctly formatted. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:56 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Rename some L3 specific functions With the arrival of monitor events tied to new domains associated with a different resource it would be clearer if the L3 resource specific functions are more accurately named. Rename three groups of functions: Functions that allocate/free architecture per-RMID MBM state information: arch_domain_mbm_alloc() -> l3_mon_domain_mbm_alloc() mon_domain_free() -> l3_mon_domain_free() Functions that allocate/free filesystem per-RMID MBM state information: domain_setup_mon_state() -> domain_setup_l3_mon_state() domain_destroy_mon_state() -> domain_destroy_l3_mon_state() Initialization/exit: rdt_get_mon_l3_config() -> rdt_get_l3_mon_config() resctrl_mon_resource_init() -> resctrl_l3_mon_resource_init() resctrl_mon_resource_exit() -> resctrl_l3_mon_resource_exit() Ensure kernel-doc descriptions of these functions' return values are present and correctly formatted. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:56 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Compute number of RMIDs as minimum across resources resctrl assumes that only the L3 resource supports monitor events, so it simply takes the rdt_resource::num_rmid from RDT_RESOURCE_L3 as the system's number of RMIDs. The addition of telemetry events in a different resource breaks that assumption. Compute the number of available RMIDs as the minimum value across all mon_capable resources (analogous to how the number of CLOSIDs is computed across alloc_capable resources). Note that mount time enumeration of the telemetry resource means that this number can be reduced. If this happens, then some memory will be wasted as the allocations for rdt_l3_mon_domain::mbm_states[] and rdt_l3_mon_domain::rmid_busy_llc created during resctrl initialization will be larger than needed. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:21:14 -08:00
x86,fs/resctrl: Rename some L3 specific functions With the arrival of monitor events tied to new domains associated with a different resource it would be clearer if the L3 resource specific functions are more accurately named. Rename three groups of functions: Functions that allocate/free architecture per-RMID MBM state information: arch_domain_mbm_alloc() -> l3_mon_domain_mbm_alloc() mon_domain_free() -> l3_mon_domain_free() Functions that allocate/free filesystem per-RMID MBM state information: domain_setup_mon_state() -> domain_setup_l3_mon_state() domain_destroy_mon_state() -> domain_destroy_l3_mon_state() Initialization/exit: rdt_get_mon_l3_config() -> rdt_get_l3_mon_config() resctrl_mon_resource_init() -> resctrl_l3_mon_resource_init() resctrl_mon_resource_exit() -> resctrl_l3_mon_resource_exit() Ensure kernel-doc descriptions of these functions' return values are present and correctly formatted. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:56 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Rename some L3 specific functions With the arrival of monitor events tied to new domains associated with a different resource it would be clearer if the L3 resource specific functions are more accurately named. Rename three groups of functions: Functions that allocate/free architecture per-RMID MBM state information: arch_domain_mbm_alloc() -> l3_mon_domain_mbm_alloc() mon_domain_free() -> l3_mon_domain_free() Functions that allocate/free filesystem per-RMID MBM state information: domain_setup_mon_state() -> domain_setup_l3_mon_state() domain_destroy_mon_state() -> domain_destroy_l3_mon_state() Initialization/exit: rdt_get_mon_l3_config() -> rdt_get_l3_mon_config() resctrl_mon_resource_init() -> resctrl_l3_mon_resource_init() resctrl_mon_resource_exit() -> resctrl_l3_mon_resource_exit() Ensure kernel-doc descriptions of these functions' return values are present and correctly formatted. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:56 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Prepare for more monitor events There's a rule in computer programming that objects appear zero, once, or many times. So code accordingly. There are two MBM events and resctrl is coded with a lot of if (local) do one thing if (total) do a different thing Change the rdt_mon_domain and rdt_hw_mon_domain structures to hold arrays of pointers to per event data instead of explicit fields for total and local bandwidth. Simplify by coding for many events using loops on which are enabled. Move resctrl_is_mbm_event() to <linux/resctrl.h> so it can be used more widely. Also provide a for_each_mbm_event_id() helper macro. Cleanup variable names in functions touched to consistently use "eventid" for those with type enum resctrl_event_id. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:03 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Replace architecture event enabled checks The resctrl file system now has complete knowledge of the status of every event. So there is no need for per-event function calls to check. Replace each of the resctrl_arch_is_{event}enabled() calls with resctrl_is_mon_event_enabled(QOS_{EVENT}). No functional change. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:01 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Prepare for more monitor events There's a rule in computer programming that objects appear zero, once, or many times. So code accordingly. There are two MBM events and resctrl is coded with a lot of if (local) do one thing if (total) do a different thing Change the rdt_mon_domain and rdt_hw_mon_domain structures to hold arrays of pointers to per event data instead of explicit fields for total and local bandwidth. Simplify by coding for many events using loops on which are enabled. Move resctrl_is_mbm_event() to <linux/resctrl.h> so it can be used more widely. Also provide a for_each_mbm_event_id() helper macro. Cleanup variable names in functions touched to consistently use "eventid" for those with type enum resctrl_event_id. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:03 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Introduce mbm_cntr_cfg to track assignable counters per domain The "mbm_event" counter assignment mode allows users to assign a hardware counter to an RMID, event pair and monitor bandwidth usage as long as it is assigned. The hardware continues to track the assigned counter until it is explicitly unassigned by the user. Counters are assigned/unassigned at monitoring domain level. Manage a monitoring domain's hardware counters using a per monitoring domain array of struct mbm_cntr_cfg that is indexed by the hardware counter ID. A hardware counter's configuration contains the MBM event ID and points to the monitoring group that it is assigned to, with a NULL pointer meaning that the hardware counter is available for assignment. There is no direct way to determine which hardware counters are assigned to a particular monitoring group. Check every entry of every hardware counter configuration array in every monitoring domain to query which MBM events of a monitoring group is tracked by hardware. Such queries are acceptable because of a very small number of assignable counters (32 to 64). Suggested-by: Peter Newman <peternewman@google.com> Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:11 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Prepare for more monitor events There's a rule in computer programming that objects appear zero, once, or many times. So code accordingly. There are two MBM events and resctrl is coded with a lot of if (local) do one thing if (total) do a different thing Change the rdt_mon_domain and rdt_hw_mon_domain structures to hold arrays of pointers to per event data instead of explicit fields for total and local bandwidth. Simplify by coding for many events using loops on which are enabled. Move resctrl_is_mbm_event() to <linux/resctrl.h> so it can be used more widely. Also provide a for_each_mbm_event_id() helper macro. Cleanup variable names in functions touched to consistently use "eventid" for those with type enum resctrl_event_id. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:03 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Refactor domain create/remove using struct rdt_domain_hdr Up until now, all monitoring events were associated with the L3 resource and it made sense to use the L3 specific "struct rdt_mon_domain *" argument to functions operating on domains. Telemetry events will be tied to a new resource with its instances represented by a new domain structure that, just like struct rdt_mon_domain, starts with the generic struct rdt_domain_hdr. Prepare to support domains belonging to different resources by changing the calling convention of functions operating on domains. Pass the generic header and use that to find the domain specific structure where needed. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:52 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Rename struct rdt_mon_domain and rdt_hw_mon_domain The upcoming telemetry event monitoring is not tied to the L3 resource and will have a new domain structure. Rename the L3 resource specific domain data structures to include "l3_" in their names to avoid confusion between the different resource specific domain structures: rdt_mon_domain -> rdt_l3_mon_domain rdt_hw_mon_domain -> rdt_hw_l3_mon_domain No functional change. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:55 -08:00
x86,fs/resctrl: Refactor domain create/remove using struct rdt_domain_hdr Up until now, all monitoring events were associated with the L3 resource and it made sense to use the L3 specific "struct rdt_mon_domain *" argument to functions operating on domains. Telemetry events will be tied to a new resource with its instances represented by a new domain structure that, just like struct rdt_mon_domain, starts with the generic struct rdt_domain_hdr. Prepare to support domains belonging to different resources by changing the calling convention of functions operating on domains. Pass the generic header and use that to find the domain specific structure where needed. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:52 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Handle domain creation/deletion for RDT_RESOURCE_PERF_PKG The L3 resource has several requirements for domains. There are per-domain structures that hold the 64-bit values of counters, and elements to keep track of the overflow and limbo threads. None of these are needed for the PERF_PKG resource. The hardware counters are wide enough that they do not wrap around for decades. Define a new rdt_perf_pkg_mon_domain structure which just consists of the standard rdt_domain_hdr to keep track of domain id and CPU mask. Update resctrl_online_mon_domain() for RDT_RESOURCE_PERF_PKG. The only action needed for this resource is to create and populate domain directories if a domain is added while resctrl is mounted. Similarly resctrl_offline_mon_domain() only needs to remove domain directories. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:21:10 -08:00
x86,fs/resctrl: Refactor domain create/remove using struct rdt_domain_hdr Up until now, all monitoring events were associated with the L3 resource and it made sense to use the L3 specific "struct rdt_mon_domain *" argument to functions operating on domains. Telemetry events will be tied to a new resource with its instances represented by a new domain structure that, just like struct rdt_mon_domain, starts with the generic struct rdt_domain_hdr. Prepare to support domains belonging to different resources by changing the calling convention of functions operating on domains. Pass the generic header and use that to find the domain specific structure where needed. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:52 -08:00
x86,fs/resctrl: Rename struct rdt_mon_domain and rdt_hw_mon_domain The upcoming telemetry event monitoring is not tied to the L3 resource and will have a new domain structure. Rename the L3 resource specific domain data structures to include "l3_" in their names to avoid confusion between the different resource specific domain structures: rdt_mon_domain -> rdt_l3_mon_domain rdt_hw_mon_domain -> rdt_hw_l3_mon_domain No functional change. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:55 -08:00
x86,fs/resctrl: Rename some L3 specific functions With the arrival of monitor events tied to new domains associated with a different resource it would be clearer if the L3 resource specific functions are more accurately named. Rename three groups of functions: Functions that allocate/free architecture per-RMID MBM state information: arch_domain_mbm_alloc() -> l3_mon_domain_mbm_alloc() mon_domain_free() -> l3_mon_domain_free() Functions that allocate/free filesystem per-RMID MBM state information: domain_setup_mon_state() -> domain_setup_l3_mon_state() domain_destroy_mon_state() -> domain_destroy_l3_mon_state() Initialization/exit: rdt_get_mon_l3_config() -> rdt_get_l3_mon_config() resctrl_mon_resource_init() -> resctrl_l3_mon_resource_init() resctrl_mon_resource_exit() -> resctrl_l3_mon_resource_exit() Ensure kernel-doc descriptions of these functions' return values are present and correctly formatted. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:56 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Replace architecture event enabled checks The resctrl file system now has complete knowledge of the status of every event. So there is no need for per-event function calls to check. Replace each of the resctrl_arch_is_{event}enabled() calls with resctrl_is_mon_event_enabled(QOS_{EVENT}). No functional change. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:01 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Handle domain creation/deletion for RDT_RESOURCE_PERF_PKG The L3 resource has several requirements for domains. There are per-domain structures that hold the 64-bit values of counters, and elements to keep track of the overflow and limbo threads. None of these are needed for the PERF_PKG resource. The hardware counters are wide enough that they do not wrap around for decades. Define a new rdt_perf_pkg_mon_domain structure which just consists of the standard rdt_domain_hdr to keep track of domain id and CPU mask. Update resctrl_online_mon_domain() for RDT_RESOURCE_PERF_PKG. The only action needed for this resource is to create and populate domain directories if a domain is added while resctrl is mounted. Similarly resctrl_offline_mon_domain() only needs to remove domain directories. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:21:10 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Refactor domain create/remove using struct rdt_domain_hdr Up until now, all monitoring events were associated with the L3 resource and it made sense to use the L3 specific "struct rdt_mon_domain *" argument to functions operating on domains. Telemetry events will be tied to a new resource with its instances represented by a new domain structure that, just like struct rdt_mon_domain, starts with the generic struct rdt_domain_hdr. Prepare to support domains belonging to different resources by changing the calling convention of functions operating on domains. Pass the generic header and use that to find the domain specific structure where needed. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:52 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Rename struct rdt_mon_domain and rdt_hw_mon_domain The upcoming telemetry event monitoring is not tied to the L3 resource and will have a new domain structure. Rename the L3 resource specific domain data structures to include "l3_" in their names to avoid confusion between the different resource specific domain structures: rdt_mon_domain -> rdt_l3_mon_domain rdt_hw_mon_domain -> rdt_hw_l3_mon_domain No functional change. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:55 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Rename struct rdt_mon_domain and rdt_hw_mon_domain The upcoming telemetry event monitoring is not tied to the L3 resource and will have a new domain structure. Rename the L3 resource specific domain data structures to include "l3_" in their names to avoid confusion between the different resource specific domain structures: rdt_mon_domain -> rdt_l3_mon_domain rdt_hw_mon_domain -> rdt_hw_l3_mon_domain No functional change. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:55 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Document safe RCU list traversal rdt_resource::ctrl_domains and rdt_resource::mon_domains are RCU lists with entries added and removed by architecture from CPU hotplug callbacks that are run with cpus_write_lock() held. These lists can be traversed safely from resctrl fs by either holding cpus_read_lock() or relying on an RCU read-side critical section. resctrl fs traversals of rdt_resource::ctrl_domains and rdt_resource::mon_domains are done using list_for_each_entry() with cpus_read_lock() held. Similarly, x86 architecture callbacks use list_for_each_entry() expecting that resctrl fs makes the call with cpus_read_lock() held. Inconsistently, a lockdep_assert_cpus_held() precedes the list_for_each_entry() call with varying distance to document this safe RCU list traversal. In preparation for an upcoming traversal of rdt_resource::ctrl_domains that needs to be done from RCU read-side critical section there is a requirement for developers to always know exactly in which context the list is being traversed. Replace the list_for_each_entry() traversals of RCU list with list_for_each_entry_rcu() to document that an RCU list is being traversed while making use of the built-in lockdep expression that additionally documents that it is cpus_read_lock() that enables the list to be traversed from non-RCU protection. Only revert to documenting the safety of traversal using a comment when lockdep does not have needed visibility in functions called via smp_call*(). The lockdep expression within list_for_each_entry_rcu() depends on RCU_EXPERT that is not set in a typical debug kernel so keep the existing lockdep_assert_cpus_held() that is active with CONFIG_LOCKDEP=y found in typical debug kernel. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://patch.msgid.link/d9373f8da8ffde667740e186ffc96ab69628ac9a.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:37 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Rename struct rdt_mon_domain and rdt_hw_mon_domain The upcoming telemetry event monitoring is not tied to the L3 resource and will have a new domain structure. Rename the L3 resource specific domain data structures to include "l3_" in their names to avoid confusion between the different resource specific domain structures: rdt_mon_domain -> rdt_l3_mon_domain rdt_hw_mon_domain -> rdt_hw_l3_mon_domain No functional change. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:55 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Fix UAF from worker threads when domains are removed The mbm_handle_overflow() and cqm_handle_limbo() workers read event counters and may sleep while doing so. They are scheduled via delayed_work embedded in struct rdt_l3_mon_domain. Architecture allocates and frees these domains from CPU hotplug callbacks under cpus_write_lock(), and the workers acquire cpus_read_lock() to keep the domain alive across their access. A use-after-free can occur when a worker is blocked waiting for cpus_read_lock() while the hotplug core holds cpus_write_lock(): the architecture frees the rdt_l3_mon_domain that contains the worker's work_struct. When the worker unblocks, the container_of() it performs on the embedded work pointer dereferences freed memory. Drop cpus_read_lock() from the workers and instead drain pending and in-flight work synchronously before the architecture can free the domain. Since architecture offlines the domain under cpus_write_lock() after it has been unlinked from the RCU list and a grace period has elapsed, no new work can be scheduled. The cancel only needs to wait out existing work. Drop rdtgroup_mutex during CPU offline around cancel_delayed_work_sync() so that a worker waiting on the mutex can complete before re-pinning the work on a different CPU. When offlining a CPU the architecture may iterate over resources in any order. For example, the MBA control domain may be offlined before or after a corresponding L3 monitor domain. Ensure that resctrl fs cancels the workers no matter what order the architecture offlines the domains. Fixes: 24247aeeabe9 ("x86/intel_rdt/cqm: Improve limbo list processing") Closes: https://sashiko.dev/#/patchset/20260429184858.36423-1-tony.luck%40intel.com # [1] Reported-by: Sashiko <sashiko-bot@kernel.org> Co-developed-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://patch.msgid.link/3f0e0752deb3421606dfc4600f0ab3a4ae098cd7.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:43 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Replace architecture event enabled checks The resctrl file system now has complete knowledge of the status of every event. So there is no need for per-event function calls to check. Replace each of the resctrl_arch_is_{event}enabled() calls with resctrl_is_mon_event_enabled(QOS_{EVENT}). No functional change. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
2025-09-05 16:34:01 -05:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Fix UAF from worker threads when domains are removed The mbm_handle_overflow() and cqm_handle_limbo() workers read event counters and may sleep while doing so. They are scheduled via delayed_work embedded in struct rdt_l3_mon_domain. Architecture allocates and frees these domains from CPU hotplug callbacks under cpus_write_lock(), and the workers acquire cpus_read_lock() to keep the domain alive across their access. A use-after-free can occur when a worker is blocked waiting for cpus_read_lock() while the hotplug core holds cpus_write_lock(): the architecture frees the rdt_l3_mon_domain that contains the worker's work_struct. When the worker unblocks, the container_of() it performs on the embedded work pointer dereferences freed memory. Drop cpus_read_lock() from the workers and instead drain pending and in-flight work synchronously before the architecture can free the domain. Since architecture offlines the domain under cpus_write_lock() after it has been unlinked from the RCU list and a grace period has elapsed, no new work can be scheduled. The cancel only needs to wait out existing work. Drop rdtgroup_mutex during CPU offline around cancel_delayed_work_sync() so that a worker waiting on the mutex can complete before re-pinning the work on a different CPU. When offlining a CPU the architecture may iterate over resources in any order. For example, the MBA control domain may be offlined before or after a corresponding L3 monitor domain. Ensure that resctrl fs cancels the workers no matter what order the architecture offlines the domains. Fixes: 24247aeeabe9 ("x86/intel_rdt/cqm: Improve limbo list processing") Closes: https://sashiko.dev/#/patchset/20260429184858.36423-1-tony.luck%40intel.com # [1] Reported-by: Sashiko <sashiko-bot@kernel.org> Co-developed-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://patch.msgid.link/3f0e0752deb3421606dfc4600f0ab3a4ae098cd7.1783963505.git.reinette.chatre@intel.com
2026-07-13 10:39:43 -07:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
fs/resctrl: Introduce interface to display "io_alloc" support Introduce the "io_alloc" resctrl file to the "info" area of a cache resource, for example /sys/fs/resctrl/info/L3/io_alloc. "io_alloc" indicates support for the "io_alloc" feature that allows direct insertion of data from I/O devices into the cache. Restrict exposing support for "io_alloc" to the L3 resource that is the only resource where this feature can be backed by AMD's L3 Smart Data Cache Injection Allocation Enforcement (SDCIAE). With that, the "io_alloc" file is only visible to user space if the L3 resource supports "io_alloc". Doing so makes the file visible for all cache resources though, for example also L2 cache (if it supports cache allocation). As a consequence, add capability for file to report expected "enabled" and "disabled", as well as "not supported". Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://patch.msgid.link/e8b116a8f424128b227734bb1d433c14af478d90.1762995456.git.babu.moger@amd.com
2025-11-12 18:57:31 -06:00
x86,fs/resctrl: Rename some L3 specific functions With the arrival of monitor events tied to new domains associated with a different resource it would be clearer if the L3 resource specific functions are more accurately named. Rename three groups of functions: Functions that allocate/free architecture per-RMID MBM state information: arch_domain_mbm_alloc() -> l3_mon_domain_mbm_alloc() mon_domain_free() -> l3_mon_domain_free() Functions that allocate/free filesystem per-RMID MBM state information: domain_setup_mon_state() -> domain_setup_l3_mon_state() domain_destroy_mon_state() -> domain_destroy_l3_mon_state() Initialization/exit: rdt_get_mon_l3_config() -> rdt_get_l3_mon_config() resctrl_mon_resource_init() -> resctrl_l3_mon_resource_init() resctrl_mon_resource_exit() -> resctrl_l3_mon_resource_exit() Ensure kernel-doc descriptions of these functions' return values are present and correctly formatted. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:56 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Rename some L3 specific functions With the arrival of monitor events tied to new domains associated with a different resource it would be clearer if the L3 resource specific functions are more accurately named. Rename three groups of functions: Functions that allocate/free architecture per-RMID MBM state information: arch_domain_mbm_alloc() -> l3_mon_domain_mbm_alloc() mon_domain_free() -> l3_mon_domain_free() Functions that allocate/free filesystem per-RMID MBM state information: domain_setup_mon_state() -> domain_setup_l3_mon_state() domain_destroy_mon_state() -> domain_destroy_l3_mon_state() Initialization/exit: rdt_get_mon_l3_config() -> rdt_get_l3_mon_config() resctrl_mon_resource_init() -> resctrl_l3_mon_resource_init() resctrl_mon_resource_exit() -> resctrl_l3_mon_resource_exit() Ensure kernel-doc descriptions of these functions' return values are present and correctly formatted. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:56 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Rename some L3 specific functions With the arrival of monitor events tied to new domains associated with a different resource it would be clearer if the L3 resource specific functions are more accurately named. Rename three groups of functions: Functions that allocate/free architecture per-RMID MBM state information: arch_domain_mbm_alloc() -> l3_mon_domain_mbm_alloc() mon_domain_free() -> l3_mon_domain_free() Functions that allocate/free filesystem per-RMID MBM state information: domain_setup_mon_state() -> domain_setup_l3_mon_state() domain_destroy_mon_state() -> domain_destroy_l3_mon_state() Initialization/exit: rdt_get_mon_l3_config() -> rdt_get_l3_mon_config() resctrl_mon_resource_init() -> resctrl_l3_mon_resource_init() resctrl_mon_resource_exit() -> resctrl_l3_mon_resource_exit() Ensure kernel-doc descriptions of these functions' return values are present and correctly formatted. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:56 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Rename some L3 specific functions With the arrival of monitor events tied to new domains associated with a different resource it would be clearer if the L3 resource specific functions are more accurately named. Rename three groups of functions: Functions that allocate/free architecture per-RMID MBM state information: arch_domain_mbm_alloc() -> l3_mon_domain_mbm_alloc() mon_domain_free() -> l3_mon_domain_free() Functions that allocate/free filesystem per-RMID MBM state information: domain_setup_mon_state() -> domain_setup_l3_mon_state() domain_destroy_mon_state() -> domain_destroy_l3_mon_state() Initialization/exit: rdt_get_mon_l3_config() -> rdt_get_l3_mon_config() resctrl_mon_resource_init() -> resctrl_l3_mon_resource_init() resctrl_mon_resource_exit() -> resctrl_l3_mon_resource_exit() Ensure kernel-doc descriptions of these functions' return values are present and correctly formatted. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:56 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00
x86,fs/resctrl: Rename some L3 specific functions With the arrival of monitor events tied to new domains associated with a different resource it would be clearer if the L3 resource specific functions are more accurately named. Rename three groups of functions: Functions that allocate/free architecture per-RMID MBM state information: arch_domain_mbm_alloc() -> l3_mon_domain_mbm_alloc() mon_domain_free() -> l3_mon_domain_free() Functions that allocate/free filesystem per-RMID MBM state information: domain_setup_mon_state() -> domain_setup_l3_mon_state() domain_destroy_mon_state() -> domain_destroy_l3_mon_state() Initialization/exit: rdt_get_mon_l3_config() -> rdt_get_l3_mon_config() resctrl_mon_resource_init() -> resctrl_l3_mon_resource_init() resctrl_mon_resource_exit() -> resctrl_l3_mon_resource_exit() Ensure kernel-doc descriptions of these functions' return values are present and correctly formatted. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:20:56 -08:00
fs/resctrl: Move RMID initialization to first mount L3 monitor features are enumerated during resctrl initialization and rmid_ptrs[] that tracks all RMIDs and depends on the number of supported RMIDs is allocated during this time. Telemetry monitor features are enumerated during first resctrl mount and may support a different number of RMIDs compared to L3 monitor features. Delay allocation and initialization of rmid_ptrs[] until first mount. Since the number of RMIDs cannot change on later mounts, keep the same set of rmid_ptrs[] until resctrl_exit(). This is required because the limbo handler keeps running after resctrl is unmounted and needs to access rmid_ptrs[] as it keeps tracking busy RMIDs after unmount. Rename routines to match what they now do: dom_data_init() -> setup_rmid_lru_list() dom_data_exit() -> free_rmid_lru_list() Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2025-12-17 09:21:15 -08:00
x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-15 16:58:54 +00:00