Commit f9835c88 authored by Kan Liang's avatar Kan Liang Committed by Yunying Sun
Browse files

perf/x86/uncore: Correct the number of CHAs on EMR

mainline inclusion
from mainline-v6.6-rc1
commit 6f7f984f
category: bugfix
bugzilla: https://gitee.com/openeuler/intel-kernel/issues/I8AR40
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=6f7f984fa85b305799076a1bcec941b9377587de



Intel-SIG: commit 6f7f984f perf/x86/uncore: Correct the number of CHAs on EMR
Backport SPR and EMR PMU related upstream bugfixes to kernel 5.10.

-------------------------------------

Starting from SPR, the basic uncore PMON information is retrieved from
the discovery table (resides in an MMIO space populated by BIOS). It is
called the discovery method. The existing value of the type->num_boxes
is from the discovery table.

On some SPR variants, there is a firmware bug that makes the value from the
discovery table incorrect. We use the value from the
SPR_MSR_UNC_CBO_CONFIG MSR to replace the one from the discovery table:

   38776cc4 ("perf/x86/uncore: Correct the number of CHAs on SPR")

Unfortunately, the SPR_MSR_UNC_CBO_CONFIG isn't available for the EMR
XCC (Always returns 0), but the above firmware bug doesn't impact the
EMR XCC.

Don't let the value from the MSR replace the existing value from the
discovery table.

Fixes: 38776cc4 ("perf/x86/uncore: Correct the number of CHAs on SPR")
Reported-by: default avatarStephane Eranian <eranian@google.com>
Reported-by: default avatarYunying Sun <yunying.sun@intel.com>
Signed-off-by: default avatarKan Liang <kan.liang@linux.intel.com>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Tested-by: default avatarYunying Sun <yunying.sun@intel.com>
Link: https://lore.kernel.org/r/20230905134248.496114-1-kan.liang@linux.intel.com


Signed-off-by: default avatarYunying Sun <yunying.sun@intel.com>
parent 378c9eaa
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