lkml.org 
[lkml]   [2024]   [Apr]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    SubjectRe: [RFC PATCH 27/41] KVM: x86/pmu: Clear PERF_METRICS MSR for guest
    From

    On 4/12/2024 5:50 AM, Sean Christopherson wrote:
    > 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?

    Sure. MSR_PERF_METRICS actually reports the perf topdown metrics
    portion. I would add more details.


    >
    >> 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
    >>

    \
     
     \ /
      Last update: 2024-05-27 16:39    [W:4.170 / U:0.012 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site