[PATCH 6/6] KVM: x86: Mask off reserved bits in CPUID.8000001FH

From: Jim Mattson <jmattson@google.com>
To: kvm@vger.kernel.org, pbonzini@redhat.com, seanjc@google.com
Cc: Jim Mattson <jmattson@google.com>
Subject: [PATCH 6/6] KVM: x86: Mask off reserved bits in CPUID.8000001FH
Date: Thu, 29 Sep 2022 15:52:03 -0700	[thread overview]
Message-ID: <20220929225203.2234702-6-jmattson@google.com> (raw)
In-Reply-To: <20220929225203.2234702-1-jmattson@google.com>

KVM_GET_SUPPORTED_CPUID should only enumerate features that KVM
actually supports. CPUID.8000001FH:EBX[31:16] are reserved bits and
should be masked off.

Fixes: 8765d75329a3 ("KVM: X86: Extend CPUID range to include new leaf")
Signed-off-by: Jim Mattson <jmattson@google.com>
---
 arch/x86/kvm/cpuid.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 576cbcf489ce..58dabc9e54db 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -1188,7 +1188,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 			entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
 		} else {
 			cpuid_entry_override(entry, CPUID_8000_001F_EAX);
-
+			entry->ebx &= ~GENMASK(31, 16);
 			/*
 			 * Enumerate '0' for "PA bits reduction", the adjusted
 			 * MAXPHYADDR is enumerated directly (see 0x80000008).
-- 
2.38.0.rc1.362.ged0d419d3c-goog

