Commit d338d878 authored by Like Xu's avatar Like Xu Committed by Sean Christopherson
Browse files

KVM: x86/pmu: Advertise PERFCTR_CORE iff the min nr of counters is met 



Enable and advertise PERFCTR_CORE if and only if the minimum number of
required counters are available, i.e. if perf says there are less than six
general purpose counters.

Opportunistically, use kvm_cpu_cap_check_and_set() instead of open coding
the check for host support.

Suggested-by: default avatarSean Christopherson <seanjc@google.com>
Signed-off-by: default avatarLike Xu <likexu@tencent.com>
[sean: massage shortlog and changelog]
Link: https://lore.kernel.org/r/20230603011058.1038821-9-seanjc@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent 6a08083f

arch/x86/kvm/svm/svm.c

+12 −3
Original line number Diff line number Diff line
@@ -5025,9 +5025,18 @@ static __init void svm_set_cpu_caps(void) 
	    boot_cpu_has(X86_FEATURE_AMD_SSBD))

		kvm_cpu_cap_set(X86_FEATURE_VIRT_SSBD);



	/* AMD PMU PERFCTR_CORE CPUID */

	if (enable_pmu && boot_cpu_has(X86_FEATURE_PERFCTR_CORE))

		kvm_cpu_cap_set(X86_FEATURE_PERFCTR_CORE);

	if (enable_pmu) {

		/*

		 * Enumerate support for PERFCTR_CORE if and only if KVM has

		 * access to enough counters to virtualize "core" support,

		 * otherwise limit vPMU support to the legacy number of counters.

		 */

		if (kvm_pmu_cap.num_counters_gp < AMD64_NUM_COUNTERS_CORE)

			kvm_pmu_cap.num_counters_gp = min(AMD64_NUM_COUNTERS,

							  kvm_pmu_cap.num_counters_gp);

		else

			kvm_cpu_cap_check_and_set(X86_FEATURE_PERFCTR_CORE);

	}



	/* CPUID 0x8000001F (SME/SEV features) */

	sev_set_cpu_caps();