From 9254beaafd12e27d48149fab3b16db372bc90ad7 Mon Sep 17 00:00:00 2001 From: Like Xu Date: Mon, 1 Feb 2021 13:10:35 +0800 Subject: [PATCH] KVM: vmx/pmu: Reduce the overhead of LBR pass-through or cancellation 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 Reviewed-by: Andi Kleen Message-Id: <20210201051039.255478-8-like.xu@linux.intel.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx/pmu_intel.c | 13 +++++++++++++ arch/x86/kvm/vmx/vmx.h | 3 +++ 2 files changed, 16 insertions(+) diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index c7dbaac..254d9fc 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -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; } /* diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h index 41bf9ad..b5679d1 100644 --- a/arch/x86/kvm/vmx/vmx.h +++ b/arch/x86/kvm/vmx/vmx.h @@ -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; }; /* -- 2.7.4