diff options
| -rw-r--r-- | Documentation/virtual/kvm/cpuid.txt | 6 | ||||
| -rw-r--r-- | arch/x86/kvm/cpuid.c | 2 |
2 files changed, 6 insertions, 2 deletions
diff --git a/Documentation/virtual/kvm/cpuid.txt b/Documentation/virtual/kvm/cpuid.txt index 882068538c9..83afe65d496 100644 --- a/Documentation/virtual/kvm/cpuid.txt +++ b/Documentation/virtual/kvm/cpuid.txt @@ -10,11 +10,15 @@ a guest. KVM cpuid functions are: function: KVM_CPUID_SIGNATURE (0x40000000) -returns : eax = 0, +returns : eax = 0x40000001, ebx = 0x4b4d564b, ecx = 0x564b4d56, edx = 0x4d. Note that this value in ebx, ecx and edx corresponds to the string "KVMKVMKVM". +The value in eax corresponds to the maximum cpuid function present in this leaf, +and will be updated if more functions are added in the future. +Note also that old hosts set eax value to 0x0. This should +be interpreted as if the value was 0x40000001. This function queries the presence of KVM cpuid leafs. diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index c2134b88103..7df1c6d839f 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -398,7 +398,7 @@ static int do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function, case KVM_CPUID_SIGNATURE: { char signature[12] = "KVMKVMKVM\0\0"; u32 *sigptr = (u32 *)signature; - entry->eax = 0; + entry->eax = KVM_CPUID_FEATURES; entry->ebx = sigptr[0]; entry->ecx = sigptr[1]; entry->edx = sigptr[2]; |