linux-kernel - [RFC PATCH 29/41] KVM: x86/pmu: Exclude existing vLBR logic from the passthrough PMU

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Date: Fri, 26 Jan 2024 16:54:32 +0800
From: Xiong Zhang <xiong.y.zhang@...ux.intel.com>
To: seanjc@...gle.com,
	pbonzini@...hat.com,
	peterz@...radead.org,
	mizhang@...gle.com,
	kan.liang@...el.com,
	zhenyuw@...ux.intel.com,
	dapeng1.mi@...ux.intel.com,
	jmattson@...gle.com
Cc: kvm@...r.kernel.org,
	linux-perf-users@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	zhiyuan.lv@...el.com,
	eranian@...gle.com,
	irogers@...gle.com,
	samantha.alt@...el.com,
	like.xu.linux@...il.com,
	chao.gao@...el.com,
	xiong.y.zhang@...ux.intel.com
Subject: [RFC PATCH 29/41] KVM: x86/pmu: Exclude existing vLBR logic from the passthrough PMU

From: Mingwei Zhang <mizhang@...gle.com>

Excluding existing vLBR logic from the passthrough PMU because the it does
not support LBR related MSRs. So to avoid any side effect, do not call
vLBR related code in both vcpu_enter_guest() and pmi injection function.

Signed-off-by: Mingwei Zhang <mizhang@...gle.com>
---
 arch/x86/kvm/vmx/pmu_intel.c | 13 ++++++++-----
 arch/x86/kvm/vmx/vmx.c       |  2 +-
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index ad0434646a29..9bbd5084a766 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -688,13 +688,16 @@ static void intel_pmu_legacy_freezing_lbrs_on_pmi(struct kvm_vcpu *vcpu)
 
 static void intel_pmu_deliver_pmi(struct kvm_vcpu *vcpu)
 {
-	u8 version = vcpu_to_pmu(vcpu)->version;
+	u8 version;
 
-	if (!intel_pmu_lbr_is_enabled(vcpu))
-		return;
+	if (!is_passthrough_pmu_enabled(vcpu)) {
+		if (!intel_pmu_lbr_is_enabled(vcpu))
+			return;
 
-	if (version > 1 && version < 4)
-		intel_pmu_legacy_freezing_lbrs_on_pmi(vcpu);
+		version = vcpu_to_pmu(vcpu)->version;
+		if (version > 1 && version < 4)
+			intel_pmu_legacy_freezing_lbrs_on_pmi(vcpu);
+	}
 }
 
 static void vmx_update_intercept_for_lbr_msrs(struct kvm_vcpu *vcpu, bool set)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index a9623351eafe..d28afa87be70 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7469,7 +7469,7 @@ static fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu)
 	pt_guest_enter(vmx);
 
 	atomic_switch_perf_msrs(vmx);
-	if (intel_pmu_lbr_is_enabled(vcpu))
+	if (!is_passthrough_pmu_enabled(&vmx->vcpu) && intel_pmu_lbr_is_enabled(vcpu))
 		vmx_passthrough_lbr_msrs(vcpu);
 
 	if (enable_preemption_timer)
-- 
2.34.1