KVM: x86: Mask off reserved bits in CPUID.80000001H

KVM_GET_SUPPORTED_CPUID should only enumerate features that KVM
actually supports. CPUID.80000001:EBX[27:16] are reserved bits and
should be masked off.

Fixes: 0771671749b5 ("KVM: Enhance guest cpuid management")
Signed-off-by: Jim Mattson <jmattson@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 7065462..834feeb 100644 (file)
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -1133,6 +1133,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
                        entry->eax = max(entry->eax, 0x80000021);
                break;
        case 0x80000001:
+               entry->ebx &= ~GENMASK(27, 16);
                cpuid_entry_override(entry, CPUID_8000_0001_EDX);
                cpuid_entry_override(entry, CPUID_8000_0001_ECX);
                break;