[PATCH 0/3] KVM: x86: Intel PERF_CAPABILITIES fix and cleanups

From: Sean Christopherson
Date: Wed Jul 27 2022 - 19:34:37 EST


Fix a bug where KVM doesn't refresh the vPMU after userspace writes
PERF_CAPABILITIES, and then leverage that fix to avoiding checking
guest_cpuid_has(X86_FEATURE_PDCM) during VM-Enter, which is slow enough
that it shows up in perf traces[*].

[*] https://gist.github.com/avagin/f50a6d569440c9ae382281448c187f4e

Sean Christopherson (3):
KVM: x86: Refresh PMU after writes to MSR_IA32_PERF_CAPABILITIES
KVM: VMX: Use proper type-safe functions for vCPU => LBRs helpers
KVM: VMX: Adjust number of LBR records for PERF_CAPABILITIES at
refresh

arch/x86/kvm/vmx/pmu_intel.c | 12 +++---------
arch/x86/kvm/vmx/vmx.h | 29 ++++++++++++++++++++---------
arch/x86/kvm/x86.c | 4 ++--
3 files changed, 25 insertions(+), 20 deletions(-)


base-commit: 1a4d88a361af4f2e91861d632c6a1fe87a9665c2
--
2.37.1.359.gd136c6c3e2-goog