KVM: x86: Explicitly zero cpuid "0xa" leaf when PMU is disabled

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@google.com>
Signed-off-by: Like Xu <likexu@tencent.com>
Link: https://lore.kernel.org/r/20230603011058.1038821-7-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 0c9660a..61bc718 100644 (file)
--- 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;
                }