linux-kernel - [PATCH 0/3] KVM: x86: Intel PERF

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Message-Id: <20220727233424.2968356-1-seanjc@google.com>
Date:   Wed, 27 Jul 2022 23:34:21 +0000
From:   Sean Christopherson <seanjc@...gle.com>
To:     Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Like Xu <like.xu.linux@...il.com>
Subject: [PATCH 0/3] KVM: x86: Intel PERF_CAPABILITIES fix and cleanups

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