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KVM: vmx/pmu: Reduce the overhead of LBR pass-through or cancellation

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When the LBR records msrs has already been pass-through, there is no
need to call vmx_update_intercept_for_lbr_msrs() again and again, and
vice versa.

Signed-off-by: Like Xu <like.xu@linux.intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Message-Id: <20210201051039.255478-8-like.xu@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Like Xu
2021-02-01 13:10:35 +08:00
committed by Paolo Bonzini
parent 1b5ac3226a
commit 9254beaafd
2 changed files with 16 additions and 0 deletions
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13
arch/x86/kvm/vmx/pmu_intel.c
View File

@@ -557,6 +557,7 @@ static void intel_pmu_init(struct kvm_vcpu *vcpu)
vcpu->arch.perf_capabilities = vmx_get_perf_capabilities();
lbr_desc->records.nr = 0;
lbr_desc->event = NULL;
lbr_desc->msr_passthrough = false;
}
static void intel_pmu_reset(struct kvm_vcpu *vcpu)
@@ -603,12 +604,24 @@ static void vmx_update_intercept_for_lbr_msrs(struct kvm_vcpu *vcpu, bool set)
static inline void vmx_disable_lbr_msrs_passthrough(struct kvm_vcpu *vcpu)
{
struct lbr_desc *lbr_desc = vcpu_to_lbr_desc(vcpu);
if (!lbr_desc->msr_passthrough)
return;
vmx_update_intercept_for_lbr_msrs(vcpu, true);
lbr_desc->msr_passthrough = false;
}
static inline void vmx_enable_lbr_msrs_passthrough(struct kvm_vcpu *vcpu)
{
struct lbr_desc *lbr_desc = vcpu_to_lbr_desc(vcpu);
if (lbr_desc->msr_passthrough)
return;
vmx_update_intercept_for_lbr_msrs(vcpu, false);
lbr_desc->msr_passthrough = true;
}
/*

3
arch/x86/kvm/vmx/vmx.h
View File

@@ -113,6 +113,9 @@ struct lbr_desc {
* The records may be inaccurate if the host reclaims the LBR.
*/
struct perf_event *event;
/* True if LBRs are marked as not intercepted in the MSR bitmap */
bool msr_passthrough;
};
/*