[PATCH v1 09/11] KVM: x86/pmu: Expose PEBS feature to guest

[Luwei Kang]

This patch exposed some bits of MSRs to KVM guest which realate with PEBS
feature. It include some bits in IA32_PERF_CAPABILITIES and IA32_MISC_ENABLE.

Originally-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Signed-off-by: Luwei Kang <luwei.kang@xxxxxxxxx>
Co-developed-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
Signed-off-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
---
 arch/x86/include/asm/kvm_host.h  |  1 +
 arch/x86/include/asm/msr-index.h |  3 +++
 arch/x86/kvm/vmx/pmu_intel.c     | 15 +++++++++++++++
 arch/x86/kvm/x86.c               |  6 +++++-
 4 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 33b990b..35d230e 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -481,6 +481,7 @@ struct kvm_pmu {
 	u64 pebs_enable;
 	u64 pebs_enable_mask;
 	u64 ds_area;
+	u64 perf_cap;
 	u8 version;
 	struct kvm_pmc gp_counters[INTEL_PMC_MAX_GENERIC];
 	struct kvm_pmc fixed_counters[INTEL_PMC_MAX_FIXED];
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index d5e517d..2bf66e9 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -151,6 +151,9 @@
 #define MSR_PEBS_DATA_CFG		0x000003f2
 #define MSR_IA32_DS_AREA		0x00000600
 #define MSR_IA32_PERF_CAPABILITIES	0x00000345
+#define PERF_CAP_PEBS_TRAP		BIT_ULL(6)
+#define PERF_CAP_ARCH_REG		BIT_ULL(7)
+#define PERF_CAP_PEBS_FORMAT		0xf00
 #define MSR_PEBS_LD_LAT_THRESHOLD	0x000003f6
 
 #define MSR_IA32_RTIT_CTL		0x00000570
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 227589a..8161488 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -180,6 +180,7 @@ static bool intel_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
 		break;
 	case MSR_IA32_DS_AREA:
 	case MSR_IA32_PEBS_ENABLE:
+	case MSR_IA32_PERF_CAPABILITIES:
 		ret = pmu->has_pebs_via_ds;
 		break;
 	default:
@@ -244,6 +245,9 @@ static int intel_pmu_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *data)
 	case MSR_IA32_DS_AREA:
 		*data = pmu->ds_area;
 		return 0;
+	case MSR_IA32_PERF_CAPABILITIES:
+		*data = pmu->perf_cap;
+		return 0;
 	default:
 		if ((pmc = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0))) {
 			u64 val = pmc_read_counter(pmc);
@@ -311,6 +315,8 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 	case MSR_IA32_DS_AREA:
 		pmu->ds_area = data;
 		return 0;
+	case MSR_IA32_PERF_CAPABILITIES:
+		break; /* RO MSR */
 	default:
 		if ((pmc = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0))) {
 			if (!msr_info->host_initiated)
@@ -396,6 +402,15 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
 		pmu->pebs_enable_mask = ~pmu->global_ctrl;
 	}
 
+	if (pmu->has_pebs_via_ds) {
+		u64 perf_cap;
+
+		rdmsrl(MSR_IA32_PERF_CAPABILITIES, perf_cap);
+		pmu->perf_cap = (perf_cap & (PERF_CAP_PEBS_TRAP |
+					     PERF_CAP_ARCH_REG |
+					     PERF_CAP_PEBS_FORMAT));
+	}
+
 	entry = kvm_find_cpuid_entry(vcpu, 7, 0);
 	if (entry &&
 	    (boot_cpu_has(X86_FEATURE_HLE) || boot_cpu_has(X86_FEATURE_RTM)) &&
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 7a23406..5ab8447 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3086,7 +3086,11 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		msr_info->data = (u64)vcpu->arch.ia32_tsc_adjust_msr;
 		break;
 	case MSR_IA32_MISC_ENABLE:
-		msr_info->data = vcpu->arch.ia32_misc_enable_msr;
+		if (vcpu_to_pmu(vcpu)->has_pebs_via_ds)
+			msr_info->data = (vcpu->arch.ia32_misc_enable_msr &
+					~MSR_IA32_MISC_ENABLE_PEBS_UNAVAIL);
+		else
+			msr_info->data = vcpu->arch.ia32_misc_enable_msr;
 		break;
 	case MSR_IA32_SMBASE:
 		if (!msr_info->host_initiated)
-- 
1.8.3.1