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| author | Gleb Natapov <gleb@redhat.com> | 2012-04-30 14:45:49 +0300 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2012-05-06 15:59:49 +0300 |
| commit | 9b72d3b07dd99ac8ab2b84de5004a295af460536 (patch) | |
| tree | 1142d76d9688772df00f1ce78faaf0075493448f | |
| parent | 57c22e5f35aa4b9b2fe11f73f3e62bbf9ef36190 (diff) | |
| download | linux-9b72d3b07dd99ac8ab2b84de5004a295af460536.tar.gz linux-9b72d3b07dd99ac8ab2b84de5004a295af460536.tar.bz2 linux-9b72d3b07dd99ac8ab2b84de5004a295af460536.zip | |
KVM guest: make kvm_para_available() check hypervisor bit reading cpuid leaf
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>
| -rw-r--r-- | arch/x86/include/asm/kvm_para.h | 18 |
1 files changed, 10 insertions, 8 deletions
diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h index 99c4bbe0cca2..a7a7a94b94ce 100644 --- a/arch/x86/include/asm/kvm_para.h +++ b/arch/x86/include/asm/kvm_para.h @@ -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 (strcmp(signature, "KVMKVMKVM") == 0) - return 1; + 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; + } return 0; } |