From: Jim Mattson <jmattson@google.com>
Date: Thu, 29 Sep 2022 22:51:58 +0000 (+0200)
Subject: KVM: x86: Mask off reserved bits in CPUID.80000001H
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=0469e56a14bf8cfb80507e51b7aeec0332cdbc13;p=linux.git

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 7065462378e29..834feeb0a828d 100644
--- 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;