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wei-w-wanggregkh
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KVM: x86: remove PMU FIXED_CTR3 from msrs_to_save_all
commit 9fb12fe upstream. The fixed counter 3 is used for the Topdown metrics, which hasn't been enabled for KVM guests. Userspace accessing to it will fail as it's not included in get_fixed_pmc(). This breaks KVM selftests on ICX+ machines, which have this counter. To reproduce it on ICX+ machines, ./state_test reports: ==== Test Assertion Failure ==== lib/x86_64/processor.c:1078: r == nmsrs pid=4564 tid=4564 - Argument list too long 1 0x000000000040b1b9: vcpu_save_state at processor.c:1077 2 0x0000000000402478: main at state_test.c:209 (discriminator 6) 3 0x00007fbe21ed5f92: ?? ??:0 4 0x000000000040264d: _start at ??:? Unexpected result from KVM_GET_MSRS, r: 17 (failed MSR was 0x30c) With this patch, it works well. Signed-off-by: Wei Wang <wei.w.wang@intel.com> Message-Id: <20211217124934.32893-1-wei.w.wang@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Fixes: e2ada66 ("kvm: x86: Add Intel PMU MSRs to msrs_to_save[]") Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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arch/x86/kvm/x86.c

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1229,7 +1229,7 @@ static const u32 msrs_to_save_all[] = {
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MSR_IA32_UMWAIT_CONTROL,
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MSR_ARCH_PERFMON_FIXED_CTR0, MSR_ARCH_PERFMON_FIXED_CTR1,
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MSR_ARCH_PERFMON_FIXED_CTR0 + 2, MSR_ARCH_PERFMON_FIXED_CTR0 + 3,
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MSR_ARCH_PERFMON_FIXED_CTR0 + 2,
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MSR_CORE_PERF_FIXED_CTR_CTRL, MSR_CORE_PERF_GLOBAL_STATUS,
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MSR_CORE_PERF_GLOBAL_CTRL, MSR_CORE_PERF_GLOBAL_OVF_CTRL,
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MSR_ARCH_PERFMON_PERFCTR0, MSR_ARCH_PERFMON_PERFCTR1,

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