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| author |   Michael S. Tsirkin <mst@redhat.com> | 2012-05-02 17:55:56 +0300 |
|---|---|---|
| committer |   Avi Kivity <avi@redhat.com> | 2012-05-06 15:51:56 +0300 |
| commit | 57c22e5f35aa4b9b2fe11f73f3e62bbf9ef36190 (patch) | |
| tree | 0ec4365a32d290c7e80d02bb67f7f28c188b39a2 /Documentation/virtual | |
| parent | KVM: s390: implement KVM_CAP_NR/MAX_VCPUS (diff) | |
| download | linux-dev-57c22e5f35aa4b9b2fe11f73f3e62bbf9ef36190.tar.xz linux-dev-57c22e5f35aa4b9b2fe11f73f3e62bbf9ef36190.zip | |
KVM: fix cpuid eax for KVM leaf
cpuid eax should return the max leaf so that
guests can find out the valid range.
This matches Xen et al.
Update documentation to match.
Tested with -cpu host.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'Documentation/virtual')
| -rw-r--r-- | Documentation/virtual/kvm/cpuid.txt | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/Documentation/virtual/kvm/cpuid.txt b/Documentation/virtual/kvm/cpuid.txt index 882068538c9c..83afe65d4966 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. |