This is a note to let you know that I've just added the patch titled
KVM: x86/pmu: Do not speculatively query Intel GP PMCs that don't exist yet
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kvm-x86-pmu-do-not-speculatively-query-intel-gp-pmcs.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 8e36458495d4d2002a7dbf3fc4067a71128a4dd2
Author: Like Xu <likexu@xxxxxxxxxxx>
Date: Mon Sep 19 17:10:06 2022 +0800
KVM: x86/pmu: Do not speculatively query Intel GP PMCs that don't exist yet
[ Upstream commit 8631ef59b62290c7d88e7209e35dfb47f33f4902 ]
The SDM lists an architectural MSR IA32_CORE_CAPABILITIES (0xCF)
that limits the theoretical maximum value of the Intel GP PMC MSRs
allocated at 0xC1 to 14; likewise the Intel April 2022 SDM adds
IA32_OVERCLOCKING_STATUS at 0x195 which limits the number of event
selection MSRs to 15 (0x186-0x194).
Limiting the maximum number of counters to 14 or 18 based on the currently
allocated MSRs is clearly fragile, and it seems likely that Intel will
even place PMCs 8-15 at a completely different range of MSR indices.
So stop at the maximum number of GP PMCs supported today on Intel
processors.
There are some machines, like Intel P4 with non Architectural PMU, that
may indeed have 18 counters, but those counters are in a completely
different MSR address range and are not supported by KVM.
Cc: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Fixes: cf05a67b68b8 ("KVM: x86: omit "impossible" pmu MSRs from MSR list")
Suggested-by: Jim Mattson <jmattson@xxxxxxxxxx>
Signed-off-by: Like Xu <likexu@xxxxxxxxxxx>
Reviewed-by: Jim Mattson <jmattson@xxxxxxxxxx>
Message-Id: <20220919091008.60695-1-likexu@xxxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 7f41e1f9f0b4..c58e23e9b5ec 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1347,20 +1347,10 @@ static const u32 msrs_to_save_all[] = {
MSR_ARCH_PERFMON_PERFCTR0 + 2, MSR_ARCH_PERFMON_PERFCTR0 + 3,
MSR_ARCH_PERFMON_PERFCTR0 + 4, MSR_ARCH_PERFMON_PERFCTR0 + 5,
MSR_ARCH_PERFMON_PERFCTR0 + 6, MSR_ARCH_PERFMON_PERFCTR0 + 7,
- MSR_ARCH_PERFMON_PERFCTR0 + 8, MSR_ARCH_PERFMON_PERFCTR0 + 9,
- MSR_ARCH_PERFMON_PERFCTR0 + 10, MSR_ARCH_PERFMON_PERFCTR0 + 11,
- MSR_ARCH_PERFMON_PERFCTR0 + 12, MSR_ARCH_PERFMON_PERFCTR0 + 13,
- MSR_ARCH_PERFMON_PERFCTR0 + 14, MSR_ARCH_PERFMON_PERFCTR0 + 15,
- MSR_ARCH_PERFMON_PERFCTR0 + 16, MSR_ARCH_PERFMON_PERFCTR0 + 17,
MSR_ARCH_PERFMON_EVENTSEL0, MSR_ARCH_PERFMON_EVENTSEL1,
MSR_ARCH_PERFMON_EVENTSEL0 + 2, MSR_ARCH_PERFMON_EVENTSEL0 + 3,
MSR_ARCH_PERFMON_EVENTSEL0 + 4, MSR_ARCH_PERFMON_EVENTSEL0 + 5,
MSR_ARCH_PERFMON_EVENTSEL0 + 6, MSR_ARCH_PERFMON_EVENTSEL0 + 7,
- MSR_ARCH_PERFMON_EVENTSEL0 + 8, MSR_ARCH_PERFMON_EVENTSEL0 + 9,
- MSR_ARCH_PERFMON_EVENTSEL0 + 10, MSR_ARCH_PERFMON_EVENTSEL0 + 11,
- MSR_ARCH_PERFMON_EVENTSEL0 + 12, MSR_ARCH_PERFMON_EVENTSEL0 + 13,
- MSR_ARCH_PERFMON_EVENTSEL0 + 14, MSR_ARCH_PERFMON_EVENTSEL0 + 15,
- MSR_ARCH_PERFMON_EVENTSEL0 + 16, MSR_ARCH_PERFMON_EVENTSEL0 + 17,
MSR_K7_EVNTSEL0, MSR_K7_EVNTSEL1, MSR_K7_EVNTSEL2, MSR_K7_EVNTSEL3,
MSR_K7_PERFCTR0, MSR_K7_PERFCTR1, MSR_K7_PERFCTR2, MSR_K7_PERFCTR3,
@@ -6449,12 +6439,12 @@ static void kvm_init_msr_list(void)
intel_pt_validate_hw_cap(PT_CAP_num_address_ranges) * 2)
continue;
break;
- case MSR_ARCH_PERFMON_PERFCTR0 ... MSR_ARCH_PERFMON_PERFCTR0 + 17:
+ case MSR_ARCH_PERFMON_PERFCTR0 ... MSR_ARCH_PERFMON_PERFCTR0 + 7:
if (msrs_to_save_all[i] - MSR_ARCH_PERFMON_PERFCTR0 >=
min(INTEL_PMC_MAX_GENERIC, x86_pmu.num_counters_gp))
continue;
break;
- case MSR_ARCH_PERFMON_EVENTSEL0 ... MSR_ARCH_PERFMON_EVENTSEL0 + 17:
+ case MSR_ARCH_PERFMON_EVENTSEL0 ... MSR_ARCH_PERFMON_EVENTSEL0 + 7:
if (msrs_to_save_all[i] - MSR_ARCH_PERFMON_EVENTSEL0 >=
min(INTEL_PMC_MAX_GENERIC, x86_pmu.num_counters_gp))
continue;
