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KVM: cpuid: mask more bits in leaf 0xd and subleaves

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- EAX=0Dh, ECX=1: output registers EBX/ECX/EDX are reserved.

- EAX=0Dh, ECX>1: output register ECX bit 0 is clear for all the CPUID
leaves we support, because variable "supported" comes from XCR0 and not
XSS.  Bits above 0 are reserved, so ECX is overall zero.  Output register
EDX is reserved.

Source: Intel Architecture Instruction Set Extensions Programming
Reference, ref. number 319433-022

Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Tested-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2014-12-04 15:11:11 +01:00
parent 412a3c411e
commit 404e0a19e1
1 changed files with 8 additions and 2 deletions
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10
arch/x86/kvm/cpuid.c
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@ -482,8 +482,14 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
entry[i].ebx =
xstate_required_size(supported,
true);
} else if (entry[i].eax == 0 || !(supported & mask))
continue;
} else {
if (entry[i].eax == 0 || !(supported & mask))
continue;
if (WARN_ON_ONCE(entry[i].ecx & 1))
continue;
}
entry[i].ecx = 0;
entry[i].edx = 0;
entry[i].flags |=
KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
++*nent;