Messages in this thread | | | Date | Thu, 11 Apr 2024 14:50:28 -0700 | Subject | Re: [RFC PATCH 27/41] KVM: x86/pmu: Clear PERF_METRICS MSR for guest | From | Sean Christopherson <> |
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On Fri, Jan 26, 2024, Xiong Zhang wrote: > From: Dapeng Mi <dapeng1.mi@linux.intel.com> > > Since perf topdown metrics feature is not supported yet, clear > PERF_METRICS MSR for guest.
Please rewrite with --verbose, I have no idea what MSR_PERF_METRICS, and thus no clue why it needs to be zeroed when loading guest context, e.g. it's not passed through, so why does it matter?
> Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com> > --- > arch/x86/kvm/vmx/pmu_intel.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c > index 4b4da7f17895..ad0434646a29 100644 > --- a/arch/x86/kvm/vmx/pmu_intel.c > +++ b/arch/x86/kvm/vmx/pmu_intel.c > @@ -916,6 +916,10 @@ static void intel_restore_pmu_context(struct kvm_vcpu *vcpu) > */ > for (i = pmu->nr_arch_fixed_counters; i < kvm_pmu_cap.num_counters_fixed; i++) > wrmsrl(MSR_CORE_PERF_FIXED_CTR0 + i, 0); > + > + /* Clear PERF_METRICS MSR since guest topdown metrics is not supported yet. */ > + if (kvm_caps.host_perf_cap & PMU_CAP_PERF_METRICS) > + wrmsrl(MSR_PERF_METRICS, 0); > } > > struct kvm_pmu_ops intel_pmu_ops __initdata = { > -- > 2.34.1 >
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