Commit 9254beaa authored by Like Xu's avatar Like Xu Committed by Paolo Bonzini
Browse files

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: default avatarLike Xu <like.xu@linux.intel.com>
Reviewed-by: default avatarAndi Kleen <ak@linux.intel.com>
Message-Id: <20210201051039.255478-8-like.xu@linux.intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 1b5ac322

arch/x86/kvm/vmx/pmu_intel.c

+13 −0
Original line number Diff line number Diff line
@@ -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;

}



/*

arch/x86/kvm/vmx/vmx.h

+3 −0
Original line number Diff line number Diff line
@@ -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;

};



/*