linux-kernel - [RFC PATCH 34/41] KVM: x86/pmu: Intercept EVENT

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Date: Fri, 26 Jan 2024 16:54:37 +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,
	Xiong Zhang <xiong.y.zhang@...el.com>
Subject: [RFC PATCH 34/41] KVM: x86/pmu: Intercept EVENT_SELECT MSR

From: Xiong Zhang <xiong.y.zhang@...el.com>

Event selectors for GP counters are still intercepted for the purpose of
security, i.e., preventing guest from using unallowed events to steal
information or take advantages of any CPU errata.

Signed-off-by: Xiong Zhang <xiong.y.zhang@...el.com>
Signed-off-by: Mingwei Zhang <mizhang@...gle.com>
---
 arch/x86/kvm/vmx/pmu_intel.c | 1 -
 arch/x86/kvm/vmx/vmx.c       | 1 -
 2 files changed, 2 deletions(-)

diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 9bbd5084a766..621922005184 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -809,7 +809,6 @@ void intel_passthrough_pmu_msrs(struct kvm_vcpu *vcpu)
 	int i;
 
 	for (i = 0; i < vcpu_to_pmu(vcpu)->nr_arch_gp_counters; i++) {
-		vmx_set_intercept_for_msr(vcpu, MSR_ARCH_PERFMON_EVENTSEL0 + i, MSR_TYPE_RW, false);
 		vmx_set_intercept_for_msr(vcpu, MSR_IA32_PERFCTR0 + i, MSR_TYPE_RW, false);
 		if (fw_writes_is_enabled(vcpu))
 			vmx_set_intercept_for_msr(vcpu, MSR_IA32_PMC0 + i, MSR_TYPE_RW, false);
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index d28afa87be70..1a518800d154 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -698,7 +698,6 @@ static bool is_valid_passthrough_msr(u32 msr)
 	case MSR_LBR_CORE_FROM ... MSR_LBR_CORE_FROM + 8:
 	case MSR_LBR_CORE_TO ... MSR_LBR_CORE_TO + 8:
 		/* LBR MSRs. These are handled in vmx_update_intercept_for_lbr_msrs() */
-	case MSR_ARCH_PERFMON_EVENTSEL0 ... MSR_ARCH_PERFMON_EVENTSEL0 + 7:
 	case MSR_IA32_PMC0 ... MSR_IA32_PMC0 + 7:
 	case MSR_IA32_PERFCTR0 ... MSR_IA32_PERFCTR0 + 7:
 	case MSR_CORE_PERF_FIXED_CTR_CTRL:
-- 
2.34.1