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

stable inclusion
from stable-v5.10.154
commit cc40c5f3e9211523873c001d34e2f6695d57249b
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I64YCB

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=cc40c5f3e9211523873c001d34e2f6695d57249b

--------------------------------

commit 079f6889 upstream.

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: 24c82e57 ("KVM: Sanitize cpuid")
Signed-off-by: NJim Mattson <jmattson@google.com>
Message-Id: <20220929225203.2234702-4-jmattson@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NLipeng Sang <sanglipeng1@jd.com>
(cherry picked from commit f7e9643b)

arch/x86/kvm/cpuid.c

@@ -986,6 +986,9 @@ 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;
 	/* Support memory encryption cpuid if host supports it */