KVM: x86: Mask off reserved bits in CPUID.8000001AH

KVM_GET_SUPPORTED_CPUID should only enumerate features that KVM
actually supports. In the case of CPUID.8000001AH, only three bits are
currently defined. The 125 reserved bits should be masked off.

Fixes: 4c6c3c2fac70 ("KVM: Sanitize cpuid")
Signed-off-by: Jim Mattson <jmattson@google.com>
Message-Id: <20220929225203.2234702-4-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 489c028859e197442bbcfbbd19cd3a36106237fe..a0292ba650df3c0bd4b0a961ff14a5d197ec6fdd 100644 (file)
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -1189,6 +1189,9 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
                entry->ecx = entry->edx = 0;
                break;
        case 0x8000001a:
+               entry->eax &= GENMASK(2, 0);
+               entry->ebx = entry->ecx = entry->edx = 0;
+               break;
        case 0x8000001e:
                break;
        case 0x8000001F: