From: Like Xu <likexu@xxxxxxxxxxx> Add an explicit !enable_pmu check as relying on kvm_pmu_cap to be zeroed isn't obvious. Although when !enable_pmu, KVM will have zero-padded kvm_pmu_cap to do subsequent cpuid leaf assignments, one extra branch instruction saves a few subsequent zero-assignment instructions, speeding things up a bit. Suggested-by: Sean Christopherson <seanjc@xxxxxxxxxx> Signed-off-by: Like Xu <likexu@xxxxxxxxxxx> --- arch/x86/kvm/cpuid.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 2a9f1e200dbc..b0bb5f9f5307 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -944,7 +944,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function) union cpuid10_eax eax; union cpuid10_edx edx; - if (!static_cpu_has(X86_FEATURE_ARCH_PERFMON)) { + if (!enable_pmu || !static_cpu_has(X86_FEATURE_ARCH_PERFMON)) { entry->eax = entry->ebx = entry->ecx = entry->edx = 0; break; } -- 2.39.1