KVM: x86/vPMU: Introduce a new kvm_pmu_ops->msr_idx_to_pmc callback

Introduce a new callback msr_idx_to_pmc that returns a struct kvm_pmc*,
and change kvm_pmu_is_valid_msr to return ".msr_idx_to_pmc(vcpu, msr) ||
.is_valid_msr(vcpu, msr)" and AMD just returns false from .is_valid_msr.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Like Xu <like.xu@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/pmu.c

@@ -334,7 +334,8 @@ void kvm_pmu_deliver_pmi(struct kvm_vcpu *vcpu)
 
 bool kvm_pmu_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
 {
-	return kvm_x86_ops->pmu_ops->is_valid_msr(vcpu, msr);
+	return kvm_x86_ops->pmu_ops->msr_idx_to_pmc(vcpu, msr) ||
+		kvm_x86_ops->pmu_ops->is_valid_msr(vcpu, msr);
 }
 
 int kvm_pmu_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *data)

arch/x86/kvm/pmu.h

@@ -27,6 +27,7 @@ struct kvm_pmu_ops {
 	struct kvm_pmc *(*pmc_idx_to_pmc)(struct kvm_pmu *pmu, int pmc_idx);
 	struct kvm_pmc *(*rdpmc_ecx_to_pmc)(struct kvm_vcpu *vcpu,
 		unsigned int idx, u64 *mask);
+	struct kvm_pmc *(*msr_idx_to_pmc)(struct kvm_vcpu *vcpu, u32 msr);
 	int (*is_valid_rdpmc_ecx)(struct kvm_vcpu *vcpu, unsigned int idx);
 	bool (*is_valid_msr)(struct kvm_vcpu *vcpu, u32 msr);
 	int (*get_msr)(struct kvm_vcpu *vcpu, u32 msr, u64 *data);

arch/x86/kvm/pmu_amd.c

@@ -199,14 +199,20 @@ static struct kvm_pmc *amd_rdpmc_ecx_to_pmc(struct kvm_vcpu *vcpu,
 }
 
 static bool amd_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
+{
+	/* All MSRs refer to exactly one PMC, so msr_idx_to_pmc is enough.  */
+	return false;
+}
+
+static struct kvm_pmc *amd_msr_idx_to_pmc(struct kvm_vcpu *vcpu, u32 msr)
 {
 	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
-	int ret = false;
+	struct kvm_pmc *pmc;
 
-	ret = get_gp_pmc_amd(pmu, msr, PMU_TYPE_COUNTER) ||
-		get_gp_pmc_amd(pmu, msr, PMU_TYPE_EVNTSEL);
+	pmc = get_gp_pmc_amd(pmu, msr, PMU_TYPE_COUNTER);
+	pmc = pmc ? pmc : get_gp_pmc_amd(pmu, msr, PMU_TYPE_EVNTSEL);
 
-	return ret;
+	return pmc;
 }
 
 static int amd_pmu_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *data)
@@ -308,6 +314,7 @@ struct kvm_pmu_ops amd_pmu_ops = {
 	.pmc_is_enabled = amd_pmc_is_enabled,
 	.pmc_idx_to_pmc = amd_pmc_idx_to_pmc,
 	.rdpmc_ecx_to_pmc = amd_rdpmc_ecx_to_pmc,
+	.msr_idx_to_pmc = amd_msr_idx_to_pmc,
 	.is_valid_rdpmc_ecx = amd_is_valid_rdpmc_ecx,
 	.is_valid_msr = amd_is_valid_msr,
 	.get_msr = amd_pmu_get_msr,

arch/x86/kvm/vmx/pmu_intel.c

@@ -162,6 +162,18 @@ static bool intel_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
 	return ret;
 }
 
+static struct kvm_pmc *intel_msr_idx_to_pmc(struct kvm_vcpu *vcpu, u32 msr)
+{
+	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
+	struct kvm_pmc *pmc;
+
+	pmc = get_fixed_pmc(pmu, msr);
+	pmc = pmc ? pmc : get_gp_pmc(pmu, msr, MSR_P6_EVNTSEL0);
+	pmc = pmc ? pmc : get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0);
+
+	return pmc;
+}
+
 static int intel_pmu_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *data)
 {
 	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
@@ -367,6 +379,7 @@ struct kvm_pmu_ops intel_pmu_ops = {
 	.pmc_is_enabled = intel_pmc_is_enabled,
 	.pmc_idx_to_pmc = intel_pmc_idx_to_pmc,
 	.rdpmc_ecx_to_pmc = intel_rdpmc_ecx_to_pmc,
+	.msr_idx_to_pmc = intel_msr_idx_to_pmc,
 	.is_valid_rdpmc_ecx = intel_is_valid_rdpmc_ecx,
 	.is_valid_msr = intel_is_valid_msr,
 	.get_msr = intel_pmu_get_msr,