Drop always returning 0 from the helper routine and simplify
its callers.
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Parav Pandit <parav@nvidia.com>
Link: https://patch.msgid.link/20250813094417.7269-2-parav@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The "rc" variable is set like this:
if (IS_ERR(resp)) {
rc = PTR_ERR(resp);
We know that "rc" is negative so there is no need to check.
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://patch.msgid.link/aJwn2ox5g9WsD2Vx@stanley.mountain
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Short: Convert the RTL8226-CG to c45 so it can be used in its
Realtek based ecosystems.
Long: The RTL8226-CG can be mainly found on devices of the
Realtek Otto switch platform. Devices like the Zyxel XGS1210-12
are based on it. These implement a hardware based phy polling
in the background to update SoC status registers.
The hardware provides 4 smi busses where phys are attached to.
For each bus one can decide if it is polled in c45 or c22 mode.
See https://svanheule.net/realtek/longan/register/smi_glb_ctrl
With this setting the register access will be limited by the
hardware. This is very complex (including caching and special
c45-over-c22 handling). But basically it boils down to "enable
protocol x and SoC will disable register access via protocol y".
Mainline already gained support for the rtl9300 mdio driver
in commit 24e31e4747 ("net: mdio: Add RTL9300 MDIO driver").
It covers the basic features, but a lot effort is still needed
to understand hardware properly. So it runs a simple setup by
selecting the proper bus mode during startup.
/* Put the interfaces into C45 mode if required */
glb_ctrl_mask = GENMASK(19, 16);
for (i = 0; i < MAX_SMI_BUSSES; i++)
if (priv->smi_bus_is_c45[i])
glb_ctrl_val |= GLB_CTRL_INTF_SEL(i);
...
err = regmap_update_bits(regmap, SMI_GLB_CTRL,
glb_ctrl_mask, glb_ctrl_val);
To avoid complex coding later on, it limits access by only
providing either c22 or c45:
bus->name = "Realtek Switch MDIO Bus";
if (priv->smi_bus_is_c45[mdio_bus]) {
bus->read_c45 = rtl9300_mdio_read_c45;
bus->write_c45 = rtl9300_mdio_write_c45;
} else {
bus->read = rtl9300_mdio_read_c22;
bus->write = rtl9300_mdio_write_c22;
}
Because of these limitations the existing RTL8226 phy driver
is not working at all on Realtek switches. Convert the driver
to c45-only.
Luckily the RTL8226 seems to support proper MDIO_PMA_EXTABLE
flags. So standard function genphy_c45_pma_read_abilities() can
call genphy_c45_pma_read_ext_abilities() and 10/100/1000 is
populated right. Thus conversion is straight forward.
Outputs before - REMARK: For this a "hacked" bus was used that
toggles the mode for each c22/c45 access. But that is slow and
produces unstable data in the SoC status registers).
Settings for lan9:
Supported ports: [ TP MII ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
2500baseT/Full
Supported pause frame use: Symmetric Receive-only
Supports auto-negotiation: Yes
Supported FEC modes: Not reported
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
2500baseT/Full
Advertised pause frame use: Symmetric Receive-only
Advertised auto-negotiation: Yes
Advertised FEC modes: Not reported
Speed: Unknown!
Duplex: Unknown! (255)
Port: Twisted Pair
PHYAD: 24
Transceiver: external
Auto-negotiation: on
MDI-X: Unknown
Supports Wake-on: d
Wake-on: d
Link detected: no
Outputs with this commit:
Settings for lan9:
Supported ports: [ TP ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
2500baseT/Full
Supported pause frame use: Symmetric Receive-only
Supports auto-negotiation: Yes
Supported FEC modes: Not reported
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
2500baseT/Full
Advertised pause frame use: Symmetric Receive-only
Advertised auto-negotiation: Yes
Advertised FEC modes: Not reported
Speed: Unknown!
Duplex: Unknown! (255)
Port: Twisted Pair
PHYAD: 24
Transceiver: external
Auto-negotiation: on
MDI-X: Unknown
Supports Wake-on: d
Wake-on: d
Link detected: no
Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de>
Link: https://patch.msgid.link/20250813054407.1108285-1-markus.stockhausen@gmx.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Add minimal LED controller driver supporting
the most common uses with the 'netdev' trigger.
Signed-off-by: Jijie Shao <shaojijie@huawei.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20250813124542.3450447-1-shaojijie@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Merge tag 'docs/v6.17-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-docs
Mauro Carvalho Chehab says:
====================
add a generic yaml parser integrated with Netlink specs generation
- An YAML parser Sphinx plugin, integrated with Netlink YAML doc
parser.
The patch content is identical to my v10 submission:
https://lore.kernel.org/cover.1753718185.git.mchehab+huawei@kernel.org
* tag 'docs/v6.17-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-docs:
sphinx: parser_yaml.py: fix line numbers information
docs: parser_yaml.py: fix backward compatibility with old docutils
docs: parser_yaml.py: add support for line numbers from the parser
tools: netlink_yml_parser.py: add line numbers to parsed data
MAINTAINERS: add netlink_yml_parser.py to linux-doc
docs: netlink: remove obsolete .gitignore from unused directory
tools: ynl_gen_rst.py: drop support for generating index files
docs: uapi: netlink: update netlink specs link
docs: use parser_yaml extension to handle Netlink specs
docs: sphinx: add a parser for yaml files for Netlink specs
tools: ynl_gen_rst.py: cleanup coding style
docs: netlink: index.rst: add a netlink index file
tools: ynl_gen_rst.py: Split library from command line tool
docs: netlink: netlink-raw.rst: use :ref: instead of :doc:
====================
Link: https://patch.msgid.link/20250812113329.356c93c2@foz.lan
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This patch implements the software flows to handle SRIOV VF
communication across an Active/Active link aggregate. The same
restrictions apply as are in place for the support of Active/Backup
bonds.
- the two interfaces must be on the same NIC
- the FW LLDP engine needs to be disabled
- the DDP package that supports VF LAG must be loaded on device
- the two interfaces must have the same QoS config
- only the first interface added to the bond will have VF support
- the interface with VFs must be in switchdev mode
With the additional requirement of
- the version of the FW on the NIC needs to have VF Active/Active support
This requirement is indicated in the capabilities struct associated
with the NVM loaded on the NIC.
The balancing of traffic between the two interfaces is done on a queue
basis. Taking the queues allocated to all of the VFs as a whole, one
half of them will be distributed to each interface. When a link goes
down, then the queues allocated to the down interface will migrate to
the active port. When the down port comes back up, then the same
queues as were originally assigned there will be moved back.
Co-developed-by: Marcin Szycik <marcin.szycik@linux.intel.com>
Signed-off-by: Marcin Szycik <marcin.szycik@linux.intel.com>
Signed-off-by: Dave Ertman <david.m.ertman@intel.com>
Tested-by: Sujai Buvaneswaran <sujai.buvaneswaran@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Update driver to use the "multi" variants of MIPI functions which
facilitate improved error handling and cleaner driver code.
Remove information from a comment which was made obsolete by commit
994ea402c7 ("drm/panel: Rename Sony ACX424 to Novatek NT35560"), which
determined that this driver supports the Novatek NT35560 panel
controller.
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Brigham Campbell <me@brighamcampbell.com>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20250731032343.1258366-4-me@brighamcampbell.com
Create mipi_dsi_dcs_read_multi(), which accepts a mipi_dsi_multi_context
struct for improved error handling and cleaner panel driver code.
Create mipi_dsi_dcs_write_var_seq_multi() and
mipi_dsi_generic_write_var_seq_multi() macros which allow MIPI panel
drivers to write non-constant data to display controllers.
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Brigham Campbell <me@brighamcampbell.com>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20250731032343.1258366-3-me@brighamcampbell.com
Forward-progress testing can hog CPUs, which is not a great thing to do
before boot has completed. This commit therefore makes the CPU-hotplug
operations hold off until boot has completed.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
CPU-hotplug operations invoke stop-machine, which can hog CPUs, which is
not a great thing to do before boot has completed. This commit therefore
makes the CPU-hotplug operations hold off until boot has completed.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The rcutorture writers and (especially) readers are the biggest CPU
hogs of the bunch, so this commit therefore makes them wait until boot
has completed.
This makes the current setting of the boot_ended local variable dead code,
so while in the area, this commit removes that as well.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
When rcutorture is running on only the one boot-time CPU while that CPU
is busy invoking initcall() functions, the added load is quite likely to
unduly delay the RCU grace-period kthread, rcutorture readers, and much
else besides. This can result in rcu_torture_stats_print() reporting
rcutorture writer stalls, which are not really a bug in that environment.
After all, one CPU can only do so much.
This commit therefore suppresses rcutorture writer stalls while the
kernel is booting, that is, while rcu_inkernel_boot_has_ended() continues
returning false.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Sometimes a given system takes surprisingly long to boot, for example,
in one recent case, 70 seconds instead of three seconds. It would
be good to fix these slow-boot issues, but it would also be good for
the torture tests to announce that the system was still booting at the
start of the test. Especially for tests that have a greater probability
of false positives when run in the single-CPU boot-time environment.
Yes, those tests should defend themselves, but we should also make this
situation easier to diagnose.
This commit therefore causes torture_print_module_parms() to print
"still booting" at the end of its printk() that dumps out the values of
its module parameters.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The --do-normal parameter was missing from the torture.sh script's help
text, so this commit adds it. Hopefully better late than never!
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
An embarrassing syntax error in jitter.sh makes for fixed spin time.
This commit therefore makes it be variable, as intended, albeit with
very coarse-grained adjustment.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This adds the usual scoped_guard(srcu_fast_notrace, &my_srcu) and
guard(srcu_fast_notrace)(&my_srcu).
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: <bpf@vger.kernel.org>
This commit adds no-trace variants of the srcu_read_lock_fast() and
srcu_read_unlock_fast() functions for tracing use.
[ paulmck: Apply notrace feedback from Joel Fernandes, Steven Rostedt, and Mathieu Desnoyers. ]
[ paulmck: Apply excess-notrace feedback from Boqun Feng. ]
Link: https://lore.kernel.org/all/20250721162433.10454-1-paulmck@kernel.org
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: <bpf@vger.kernel.org>
The rcu_is_watching() warnings are currently in the SRCU-tree
implementations of __srcu_read_lock_fast() and __srcu_read_unlock_fast().
However, this makes it difficult to create _notrace variants of
srcu_read_lock_fast() and srcu_read_unlock_fast(). This commit therefore
moves these checks to srcu_read_lock_fast(), srcu_read_unlock_fast(),
srcu_down_read_fast(), and srcu_up_read_fast().
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: <bpf@vger.kernel.org>
The per-CPU rcu_data structure's ->defer_qs_iw field is initialized
by IRQ_WORK_INIT_HARD(), which means that the subsequent invocation of
rcu_preempt_deferred_qs_handler() will always be executed with interrupts
disabled. This commit therefore removes the local_irq_save/restore()
operations from rcu_preempt_deferred_qs_handler() and adds a call to
lockdep_assert_irqs_disabled() in order to enable lockdep to diagnose
mistaken invocations of this function from interrupts-enabled code.
Signed-off-by: Zqiang <qiang.zhang@linux.dev>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Ever since uevent support was added for AER and EEH with commit
856e1eb9bd ("PCI/AER: Add uevents in AER and EEH error/resume"), it
reported PCI_ERS_RESULT_NONE as uevent when recovery begins.
Commit 7b42d97e99 ("PCI/ERR: Always report current recovery status for
udev") subsequently amended AER to report the actual return value of
error_detected().
Make the same change to EEH to align it with AER and s390.
Suggested-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/linux-pci/aIp6LiKJor9KLVpv@wunner.de/
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Acked-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Link: https://patch.msgid.link/20250807-add_err_uevents-v5-3-adf85b0620b0@linux.ibm.com
Since commit 7b42d97e99 ("PCI/ERR: Always report current recovery
status for udev") AER uses the result of error_detected() as parameter
to pci_uevent_ers(). As pci_uevent_ers() however does not handle
PCI_ERS_RESULT_NEED_RESET this results in a missing uevent for the
beginning of recovery if drivers request a reset. Fix this by treating
PCI_ERS_RESULT_NEED_RESET as beginning recovery.
Fixes: 7b42d97e99 ("PCI/ERR: Always report current recovery status for udev")
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20250807-add_err_uevents-v5-1-adf85b0620b0@linux.ibm.com
Remove unnecessary semicolons reported by Coccinelle/coccicheck and the
semantic patch at scripts/coccinelle/misc/semicolon.cocci.
Signed-off-by: Chen Ni <nichen@iscas.ac.cn>
Link: https://lore.kernel.org/r/20250729022735.1437560-1-nichen@iscas.ac.cn
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
The PCI core now provides generic PCI_FIND_NEXT_CAP() and
PCI_FIND_NEXT_EXT_CAP() macros to search for PCI capabilities, using
config accessors we supply.
Use them in the DWC driver to implement dw_pcie_find_capability() and
dw_pcie_find_ext_capability() instead of duplicating the algorithm.
Signed-off-by: Hans Zhang <18255117159@163.com>
[bhelgaas: commit log]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://patch.msgid.link/20250813144529.303548-5-18255117159@163.com
Checking on all undefined release_option values to return -EINVAL in
case a user is providing them to dlm_release_lockspace().
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Future patches will introduce a invalid argument check for undefined
values. All values for release_option are positive integer values to not
check on negative values as well we just change the parameter to
unsigned int.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Since commit f74dacb4c8 ("dlm: fix recovery of middle conversions")
we introduced additional debugging information if we hit the middle
conversion by using log_limit(). The DLM log_limit() functionality
requires a DLM debug option being enabled. As this case is so rarely and
excempt any potential introduced new issue with recovery we switching it
to log_rinfo() ad this is ratelimited under normal DLM loglevel.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Since commit de7b4869b4 ("dlm: add new configfs entry release_recover
for lockspace members") we are moving lockspace members into a gone list
before removing them to get additional removing attributes from
configfs. There is still a very unlikely possibility when
find_config_node() returns NULL, then for some reason the node wasn't
marked as gone but it was removed. We will just handle this case and drop
an error to observe if this case can ever happen.
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/gfs2/aJ2Ssuh8xlsTutrA@stanley.mountain/T/#u
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Move the extended Capability search logic into a PCI_FIND_NEXT_EXT_CAP()
macro that accepts a config space accessor function as an argument. This
enables controller drivers to perform Capability discovery using their
early access mechanisms prior to full device initialization while sharing
the Capability search code.
Convert the existing PCI core extended Capability search implementation to
use PCI_FIND_NEXT_EXT_CAP().
Signed-off-by: Hans Zhang <18255117159@163.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Niklas Schnelle <schnelle@linux.ibm.com>
Link: https://patch.msgid.link/20250813144529.303548-4-18255117159@163.com
The PCI Capability search functionality is duplicated across the PCI core
and several controller drivers. The core's current implementation requires
fully initialized PCI device and bus structures, which prevents controller
drivers from using it during early initialization phases before these
structures are available.
Move the Capability search logic into a PCI_FIND_NEXT_CAP() macro that
accepts a config space accessor function as an argument. This enables
controller drivers to perform Capability discovery using their early
access mechanisms prior to full device initialization while sharing the
Capability search code.
Convert the existing PCI core Capability search implementation to use
PCI_FIND_NEXT_CAP(). Controller drivers can later use this with their
early access mechanisms while maintaining the existing protection against
infinite loops through preserved TTL checks.
Signed-off-by: Hans Zhang <18255117159@163.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Niklas Schnelle <schnelle@linux.ibm.com>
Link: https://patch.msgid.link/20250813144529.303548-3-18255117159@163.com
There are very rare randconfig builds that turn on this driver but
don't already select CONFIG_AUXILIARY_BUS from another driver, and
this results in a build failure:
arm-linux-gnueabi-ld: drivers/clk/clk-npcm8xx.o: in function `npcm8xx_clock_driver_init':
clk-npcm8xx.c:(.init.text+0x18): undefined reference to `__auxiliary_driver_register'
Select the bus here, as all other clk drivers using it do.
Fixes: e0b255df02 ("clk: npcm8xx: add clock controller")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20250807072241.4190376-1-arnd@kernel.org
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Cross-merge networking fixes after downstream PR (net-6.17-rc2).
No conflicts.
Adjacent changes:
drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
d7a276a576 ("net: stmmac: rk: convert to suspend()/resume() methods")
de1e963ad0 ("net: stmmac: rk: put the PHY clock on remove")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The userprogs compiler and linker do not share the regular compiler flags.
Make sure they also fail on warnings with CONFIG_WERROR and W=e.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Reviewed-by: Nicolas Schier <nsc@kernel.org>
Link: https://lore.kernel.org/r/20250814-kbuild-werror-v2-5-c01e596309d2@linutronix.de
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
The linker and assembler do not share the compiler flags.
Make sure they also fail on warnings with CONFIG_WERROR and W=e.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Reviewed-by: Nicolas Schier <nsc@kernel.org>
Link: https://lore.kernel.org/r/20250814-kbuild-werror-v2-4-c01e596309d2@linutronix.de
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Following commit e88ca24319 ("kbuild: consolidate warning flags
in scripts/Makefile.extrawarn"), move `-Dwarnings` handling into
`Makefile.extrawarn` like C's `-Werror`.
No functional change intended.
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Nicolas Schier <nsc@kernel.org>
Link: https://lore.kernel.org/r/20250814-kbuild-werror-v2-3-c01e596309d2@linutronix.de
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
The two mechanisms have the same effect, unify their implementation.
Also avoid spurious rebuilds when switching between the two.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Reviewed-by: Nicolas Schier <nsc@kernel.org>
Link: https://lore.kernel.org/r/20250814-kbuild-werror-v2-2-c01e596309d2@linutronix.de
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
CONFIG_WERROR sets KBUILD_CPPFLAGS while W=e would only set KBUILD_CFLAGS.
As a preparation to unify the two mechanism, align their effects.
While at it, add some alignment whitespace to prepare for later additions
to the list of changed variables.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Reviewed-by: Nicolas Schier <nsc@kernel.org>
Link: https://lore.kernel.org/r/20250814-kbuild-werror-v2-1-c01e596309d2@linutronix.de
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Cross-thread attacks are generally harder as they require the victim to be
co-located on a core. However, with VMSCAPE the adversary targets belong to
the same guest execution, that are more likely to get co-located. In
particular, a thread that is currently executing userspace hypervisor
(after the IBPB) may still be targeted by a guest execution from a sibling
thread.
Issue a warning about the potential risk, except when:
- SMT is disabled
- STIBP is enabled system-wide
- Intel eIBRS is enabled (which implies STIBP protection)
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
cpu_bugs_smt_update() uses global variables from different mitigations. For
SMT updates it can't currently use vmscape_mitigation that is defined after
it.
Since cpu_bugs_smt_update() depends on many other mitigations, move it
after all mitigations are defined. With that, it can use vmscape_mitigation
in a moment.
No functional change.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
VMSCAPE is a vulnerability that exploits insufficient branch predictor
isolation between a guest and a userspace hypervisor (like QEMU). Existing
mitigations already protect kernel/KVM from a malicious guest. Userspace
can additionally be protected by flushing the branch predictors after a
VMexit.
Since it is the userspace that consumes the poisoned branch predictors,
conditionally issue an IBPB after a VMexit and before returning to
userspace. Workloads that frequently switch between hypervisor and
userspace will incur the most overhead from the new IBPB.
This new IBPB is not integrated with the existing IBPB sites. For
instance, a task can use the existing speculation control prctl() to
get an IBPB at context switch time. With this implementation, the
IBPB is doubled up: one at context switch and another before running
userspace.
The intent is to integrate and optimize these cases post-embargo.
[ dhansen: elaborate on suboptimal IBPB solution ]
Suggested-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Sean Christopherson <seanjc@google.com>
The VMSCAPE vulnerability may allow a guest to cause Branch Target
Injection (BTI) in userspace hypervisors.
Kernels (both host and guest) have existing defenses against direct BTI
attacks from guests. There are also inter-process BTI mitigations which
prevent processes from attacking each other. However, the threat in this
case is to a userspace hypervisor within the same process as the attacker.
Userspace hypervisors have access to their own sensitive data like disk
encryption keys and also typically have access to all guest data. This
means guest userspace may use the hypervisor as a confused deputy to attack
sensitive guest kernel data. There are no existing mitigations for these
attacks.
Introduce X86_BUG_VMSCAPE for this vulnerability and set it on affected
Intel and AMD CPUs.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
