[PATCH v6 15/44] KVM: x86/pmu: Snapshot host (i.e. perf's) reported PMU capabilities

Sean Christopherson
2025-12-06T00:17:57Z

Take a snapshot of the unadulterated PMU capabilities provided by perf so
that KVM can compare guest vPMU capabilities against hardware capabilities
when determining whether or not to intercept PMU MSRs (and RDPMC).

Reviewed-by: Sandipan Das <sandipan.das@amd.com>
Tested-by: Xudong Hao <xudong.hao@intel.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/pmu.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index 487ad19a236e..7c219305b61d 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -108,6 +108,8 @@ void kvm_init_pmu_capability(const struct kvm_pmu_ops *pmu_ops)
bool is_intel = boot_cpu_data.x86_vendor == X86_VENDOR_INTEL;
int min_nr_gp_ctrs = pmu_ops->MIN_NR_GP_COUNTERS;

+ perf_get_x86_pmu_capability(&kvm_host_pmu);
+
/*
* Hybrid PMUs don't play nice with virtualization without careful
* configuration by userspace, and KVM's APIs for reporting supported
--
2.52.0.223.gf5cc29aaa4-goog