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Commit ef3094c4 authored by Jim Mattson's avatar Jim Mattson Committed by Greg Kroah-Hartman
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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: 24c82e57 ("KVM: Sanitize cpuid")
Signed-off-by: default avatarJim Mattson <jmattson@google.com>
Message-Id: <20220929225203.2234702-3-jmattson@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent da1bf373

arch/x86/kvm/cpuid.c

+1 −0
Original line number Diff line number Diff line
@@ -759,6 +759,7 @@ static inline int __do_cpuid_func(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;

		entry->ebx &= kvm_cpuid_8000_0008_ebx_x86_features;

		cpuid_mask(&entry->ebx, CPUID_8000_0008_EBX);