[PATCH v6 04/10] KVM: x86: Explicitly zero cpuid "0xa" leaf when PMU is disabled

From: Like Xu
Date: Tue May 30 2023 - 02:05:08 EST


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.

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 0c9660a07b23..61bc71882f07 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -948,7 +948,7 @@ 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;
}
--
2.40.1