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KVM guest: make kvm_para_available() check hypervisor bit reading cpuid leaf

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This cpuid range does not exist on real HW and Intel spec says that
"Information returned for highest basic information leaf" will be
returned. Not very well defined.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Gleb Natapov 2012-04-30 14:45:49 +03:00 committed by Avi Kivity
parent 57c22e5f35
commit 9b72d3b07d
1 changed files with 9 additions and 7 deletions
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16
arch/x86/include/asm/kvm_para.h
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@ -178,14 +178,16 @@ static inline int kvm_para_available(void)
unsigned int eax, ebx, ecx, edx;
char signature[13];
cpuid(KVM_CPUID_SIGNATURE, &eax, &ebx, &ecx, &edx);
memcpy(signature + 0, &ebx, 4);
memcpy(signature + 4, &ecx, 4);
memcpy(signature + 8, &edx, 4);
signature[12] = 0;
if (cpu_has_hypervisor) {
cpuid(KVM_CPUID_SIGNATURE, &eax, &ebx, &ecx, &edx);
memcpy(signature + 0, &ebx, 4);
memcpy(signature + 4, &ecx, 4);
memcpy(signature + 8, &edx, 4);
signature[12] = 0;
if (strcmp(signature, "KVMKVMKVM") == 0)
return 1;
if (strcmp(signature, "KVMKVMKVM") == 0)
return 1;
}
return 0;
}