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KVM: x86: Explicitly zero-initialize on-stack CPUID unions

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Explicitly zero/empty-initialize the unions used for PMU related CPUID
entries, instead of manually zeroing all fields (hopefully), or in the
case of 0x80000022, relying on the compiler to clobber the uninitialized
bitfields.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Message-ID: <20250315024102.2361628-1-seanjc@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson 2025-03-14 19:41:02 -07:00 committed by Paolo Bonzini
parent 459a35111b
commit bc52ae0a70
1 changed files with 3 additions and 5 deletions
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8
arch/x86/kvm/cpuid.c
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@ -1427,8 +1427,8 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
}
break;
case 0xa: { /* Architectural Performance Monitoring */
union cpuid10_eax eax;
union cpuid10_edx edx;
union cpuid10_eax eax = { };
union cpuid10_edx edx = { };
if (!enable_pmu || !static_cpu_has(X86_FEATURE_ARCH_PERFMON)) {
entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
@ -1444,8 +1444,6 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
if (kvm_pmu_cap.version)
edx.split.anythread_deprecated = 1;
edx.split.reserved1 = 0;
edx.split.reserved2 = 0;
entry->eax = eax.full;
entry->ebx = kvm_pmu_cap.events_mask;
@ -1763,7 +1761,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
break;
/* AMD Extended Performance Monitoring and Debug */
case 0x80000022: {
union cpuid_0x80000022_ebx ebx;
union cpuid_0x80000022_ebx ebx = { };
entry->ecx = entry->edx = 0;
if (!enable_pmu || !kvm_cpu_cap_has(X86_FEATURE_PERFMON_V2)) {