6.6-stable review patch. If anyone has any objections, please let me know.
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From: Sean Christopherson seanjc@google.com
commit bc52ae0a708cb6fa3926d11c88e3c55e1171b4a1 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/kvm/cpuid.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-)
--- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -1011,8 +1011,8 @@ static inline int __do_cpuid_func(struct } 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; @@ -1028,8 +1028,6 @@ static inline int __do_cpuid_func(struct
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; @@ -1303,7 +1301,7 @@ static inline int __do_cpuid_func(struct 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)) {