x86/resctrl: Implement resctrl_arch_reset_cntr() and resctrl_arch_cntr_read()

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System software reads resctrl event data for a particular resource by writing
the RMID and Event Identifier (EvtID) to the QM_EVTSEL register and then
reading the event data from the QM_CTR register.

In ABMC mode, the event data of a specific counter ID is read by setting the
following fields: QM_EVTSEL.ExtendedEvtID = 1, QM_EVTSEL.EvtID = L3CacheABMC
(=1) and setting QM_EVTSEL.RMID to the desired counter ID.  Reading the QM_CTR
then returns the contents of the specified counter ID.  RMID_VAL_ERROR bit is
set if the counter configuration is invalid, or if an invalid counter ID is
set in the QM_EVTSEL.RMID field.  RMID_VAL_UNAVAIL bit is set if the counter
data is unavailable.

Introduce resctrl_arch_reset_cntr() and resctrl_arch_cntr_read() to reset and
read event data for a specific counter.

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

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Babu Moger 2025-09-05 16:34:21 -05:00 • committed by Borislav Petkov (AMD)

parent 7c9ac605e2

commit 2a65b72c16

2 changed files with 75 additions and 0 deletions

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6

arch/x86/kernel/cpu/resctrl/internal.h

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69

arch/x86/kernel/cpu/resctrl/monitor.c

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