[PATCH RFC v3 13/13] KVM: x86/pmu: Expose Topdown in MSR_IA32_PERF_CAPABILITIES

From: Dapeng Mi
Date: Tue Aug 22 2023 - 01:07:36 EST


Topdown support is enumerated via IA32_PERF_CAPABILITIES[bit 15]. Enable
this bit for guest when the feature is available on host.

Co-developed-by: Yang Weijiang <weijiang.yang@xxxxxxxxx>
Signed-off-by: Yang Weijiang <weijiang.yang@xxxxxxxxx>
Signed-off-by: Dapeng Mi <dapeng1.mi@xxxxxxxxxxxxxxx>
---
arch/x86/kvm/vmx/pmu_intel.c | 3 +++
arch/x86/kvm/vmx/vmx.c | 2 ++
2 files changed, 5 insertions(+)

diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 04ccb8c6f7e4..5783cde00054 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -614,6 +614,9 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
(((1ull << pmu->nr_arch_fixed_counters) - 1) << INTEL_PMC_IDX_FIXED));
pmu->global_ctrl_mask = counter_mask;

+ if (intel_pmu_metrics_is_enabled(vcpu))
+ pmu->global_ctrl_mask &= ~(1ULL << GLOBAL_CTRL_EN_PERF_METRICS);
+
/*
* GLOBAL_STATUS and GLOBAL_OVF_CONTROL (a.k.a. GLOBAL_STATUS_RESET)
* share reserved bit definitions. The kernel just happens to use
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index e6849f780dba..69a425be55bf 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7827,6 +7827,8 @@ static u64 vmx_get_perf_capabilities(void)
perf_cap &= ~PERF_CAP_PEBS_BASELINE;
}

+ perf_cap |= host_perf_cap & PMU_CAP_PERF_METRICS;
+
return perf_cap;
}

--
2.34.1