From 838852ad7cacdee09e9d30203de02d3bad6964d1 Mon Sep 17 00:00:00 2001 From: Jim Mattson Date: Thu, 29 Sep 2022 15:52:00 -0700 Subject: [PATCH] KVM: x86: Mask off reserved bits in CPUID.80000008H commit 7030d8530e533844e2f4b0e7476498afcd324634 upstream. KVM_GET_SUPPORTED_CPUID should only enumerate features that KVM actually supports. The following ranges of CPUID.80000008H are reserved and should be masked off: ECX[31:18] ECX[11:8] In addition, the PerfTscSize field at ECX[17:16] should also be zero because KVM does not set the PERFTSC bit at CPUID.80000001H.ECX[27]. Fixes: 24c82e576b78 ("KVM: Sanitize cpuid") Signed-off-by: Jim Mattson Message-Id: <20220929225203.2234702-3-jmattson@google.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/cpuid.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index fd1eb8600ccf6..3dbbf4b00dba4 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -663,6 +663,7 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function, g_phys_as = phys_as; entry->eax = g_phys_as | (virt_as << 8); + entry->ecx &= ~(GENMASK(31, 16) | GENMASK(11, 8)); entry->edx = 0; /* * IBRS, IBPB and VIRT_SSBD aren't necessarily present in