[PATCH v12 07/11] KVM: vmx/pmu: Unmask LBR fields in the MSR_IA32_DEBUGCTLMSR emualtion

[Like Xu]

When the LBR feature is reported by the vmx_get_perf_capabilities(),
the LBR fields in the [vmx|vcpu]_supported debugctl should be unmasked.

The debugctl msr is handled separately in vmx/svm and they're not
completely identical, hence remove the common msr handling code.

Signed-off-by: Like Xu <like.xu@xxxxxxxxxxxxxxx>
---
 arch/x86/kvm/vmx/capabilities.h | 12 ++++++++++++
 arch/x86/kvm/vmx/pmu_intel.c    | 19 +++++++++++++++++++
 arch/x86/kvm/x86.c              | 13 -------------
 3 files changed, 31 insertions(+), 13 deletions(-)

diff --git a/arch/x86/kvm/vmx/capabilities.h b/arch/x86/kvm/vmx/capabilities.h
index b633a90320ee..f6fcfabb1026 100644
--- a/arch/x86/kvm/vmx/capabilities.h
+++ b/arch/x86/kvm/vmx/capabilities.h
@@ -21,6 +21,8 @@ extern int __read_mostly pt_mode;
 #define PMU_CAP_FW_WRITES	(1ULL << 13)
 #define PMU_CAP_LBR_FMT		0x3f
 
+#define DEBUGCTLMSR_LBR_MASK		(DEBUGCTLMSR_LBR | DEBUGCTLMSR_FREEZE_LBRS_ON_PMI)
+
 struct nested_vmx_msrs {
 	/*
 	 * We only store the "true" versions of the VMX capability MSRs. We
@@ -387,4 +389,14 @@ static inline u64 vmx_get_perf_capabilities(void)
 	return perf_cap;
 }
 
+static inline u64 vmx_get_supported_debugctl(void)
+{
+	u64 val = 0;
+
+	if (vmx_get_perf_capabilities() & PMU_CAP_LBR_FMT)
+		val |= DEBUGCTLMSR_LBR_MASK;
+
+	return val;
+}
+
 #endif /* __KVM_X86_VMX_CAPS_H */
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index a953c7d633f6..d92e95b64c74 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -187,6 +187,7 @@ static bool intel_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
 	case MSR_CORE_PERF_GLOBAL_OVF_CTRL:
 		ret = pmu->version > 1;
 		break;
+	case MSR_IA32_DEBUGCTLMSR:
 	case MSR_IA32_PERF_CAPABILITIES:
 		ret = 1;
 		break;
@@ -237,6 +238,9 @@ static int intel_pmu_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 			return 1;
 		msr_info->data = vcpu->arch.perf_capabilities;
 		return 0;
+	case MSR_IA32_DEBUGCTLMSR:
+		msr_info->data = vmcs_read64(GUEST_IA32_DEBUGCTL);
+		return 0;
 	default:
 		if ((pmc = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0)) ||
 		    (pmc = get_gp_pmc(pmu, msr, MSR_IA32_PMC0))) {
@@ -282,6 +286,16 @@ static inline bool lbr_is_compatible(struct kvm_vcpu *vcpu)
 	return true;
 }
 
+static inline u64 vcpu_get_supported_debugctl(struct kvm_vcpu *vcpu)
+{
+	u64 debugctlmsr = vmx_get_supported_debugctl();
+
+	if (!lbr_is_enabled(vcpu))
+		debugctlmsr &= ~DEBUGCTLMSR_LBR_MASK;
+
+	return debugctlmsr;
+}
+
 static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 {
 	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
@@ -336,6 +350,11 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		}
 		vcpu->arch.perf_capabilities = data;
 		return 0;
+	case MSR_IA32_DEBUGCTLMSR:
+		if (data & ~vcpu_get_supported_debugctl(vcpu))
+			return 1;
+		vmcs_write64(GUEST_IA32_DEBUGCTL, data);
+		return 0;
 	default:
 		if ((pmc = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0)) ||
 		    (pmc = get_gp_pmc(pmu, msr, MSR_IA32_PMC0))) {
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 00c88c2f34e4..56f275eb4554 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2840,18 +2840,6 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 			return 1;
 		}
 		break;
-	case MSR_IA32_DEBUGCTLMSR:
-		if (!data) {
-			/* We support the non-activated case already */
-			break;
-		} else if (data & ~(DEBUGCTLMSR_LBR | DEBUGCTLMSR_BTF)) {
-			/* Values other than LBR and BTF are vendor-specific,
-			   thus reserved and should throw a #GP */
-			return 1;
-		}
-		vcpu_unimpl(vcpu, "%s: MSR_IA32_DEBUGCTLMSR 0x%llx, nop\n",
-			    __func__, data);
-		break;
 	case 0x200 ... 0x2ff:
 		return kvm_mtrr_set_msr(vcpu, msr, data);
 	case MSR_IA32_APICBASE:
@@ -3120,7 +3108,6 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 	switch (msr_info->index) {
 	case MSR_IA32_PLATFORM_ID:
 	case MSR_IA32_EBL_CR_POWERON:
-	case MSR_IA32_DEBUGCTLMSR:
 	case MSR_IA32_LASTBRANCHFROMIP:
 	case MSR_IA32_LASTBRANCHTOIP:
 	case MSR_IA32_LASTINTFROMIP:
-- 
2.21.3