On 4/12/2024 5:50 AM, Sean Christopherson wrote:
On Fri, Jan 26, 2024, Xiong Zhang wrote:
From: Dapeng Mi <dapeng1.mi@xxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxx>
---
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
