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| author | Sean Christopherson <seanjc@google.com> | 2022-07-28 01:34:24 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-08-10 21:08:30 +0200 |
| commit | 6348aafa8d24c156124f76b5a1507079c3213112 (patch) | |
| tree | a917665371c90aaacd68fa3622398c5d7456d8ea /Documentation/virt | |
| parent | KVM: VMX: Use proper type-safe functions for vCPU => LBRs helpers (diff) | |
| download | linux-6348aafa8d24c156124f76b5a1507079c3213112.tar.xz linux-6348aafa8d24c156124f76b5a1507079c3213112.zip | |
KVM: VMX: Adjust number of LBR records for PERF_CAPABILITIES at refresh
Now that the PMU is refreshed when MSR_IA32_PERF_CAPABILITIES is written
by host userspace, zero out the number of LBR records for a vCPU during
PMU refresh if PMU_CAP_LBR_FMT is not set in PERF_CAPABILITIES instead of
handling the check at run-time.
guest_cpuid_has() is expensive due to the linear search of guest CPUID
entries, intel_pmu_lbr_is_enabled() is checked on every VM-Enter, _and_
simply enumerating the same "Model" as the host causes KVM to set the
number of LBR records to a non-zero value.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220727233424.2968356-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'Documentation/virt')
0 files changed, 0 insertions, 0 deletions