Commit bc52ae0a authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

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



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: default avatarSean Christopherson <seanjc@google.com>
Reviewed-by: default avatarJim Mattson <jmattson@google.com>
Message-ID: <20250315024102.2361628-1-seanjc@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 459a3511

arch/x86/kvm/cpuid.c

+3 −5
Original line number Diff line number Diff line
@@ -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)) {