diff options
author | Rob Landley <rlandley@parallels.com> | 2011-05-06 12:22:02 -0400 |
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committer | Randy Dunlap <randy.dunlap@oracle.com> | 2011-05-06 12:22:02 -0400 |
commit | ed16648eb5b86917f0b90bdcdbc857202da72f90 (patch) | |
tree | a8198415a6c2f1909f02340b05d36e1d53b82320 /Documentation/virtual/kvm/cpuid.txt | |
parent | bfd412db9e7b0d8f7b9c09d12d07aa2ac785f1d0 (diff) |
Move kvm, uml, and lguest subdirectories under a common "virtual" directory, I.E:
cd Documentation
mkdir virtual
git mv kvm uml lguest virtual
Signed-off-by: Rob Landley <rlandley@parallels.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Diffstat (limited to 'Documentation/virtual/kvm/cpuid.txt')
-rw-r--r-- | Documentation/virtual/kvm/cpuid.txt | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/Documentation/virtual/kvm/cpuid.txt b/Documentation/virtual/kvm/cpuid.txt new file mode 100644 index 000000000000..882068538c9c --- /dev/null +++ b/Documentation/virtual/kvm/cpuid.txt | |||
@@ -0,0 +1,45 @@ | |||
1 | KVM CPUID bits | ||
2 | Glauber Costa <glommer@redhat.com>, Red Hat Inc, 2010 | ||
3 | ===================================================== | ||
4 | |||
5 | A guest running on a kvm host, can check some of its features using | ||
6 | cpuid. This is not always guaranteed to work, since userspace can | ||
7 | mask-out some, or even all KVM-related cpuid features before launching | ||
8 | a guest. | ||
9 | |||
10 | KVM cpuid functions are: | ||
11 | |||
12 | function: KVM_CPUID_SIGNATURE (0x40000000) | ||
13 | returns : eax = 0, | ||
14 | ebx = 0x4b4d564b, | ||
15 | ecx = 0x564b4d56, | ||
16 | edx = 0x4d. | ||
17 | Note that this value in ebx, ecx and edx corresponds to the string "KVMKVMKVM". | ||
18 | This function queries the presence of KVM cpuid leafs. | ||
19 | |||
20 | |||
21 | function: define KVM_CPUID_FEATURES (0x40000001) | ||
22 | returns : ebx, ecx, edx = 0 | ||
23 | eax = and OR'ed group of (1 << flag), where each flags is: | ||
24 | |||
25 | |||
26 | flag || value || meaning | ||
27 | ============================================================================= | ||
28 | KVM_FEATURE_CLOCKSOURCE || 0 || kvmclock available at msrs | ||
29 | || || 0x11 and 0x12. | ||
30 | ------------------------------------------------------------------------------ | ||
31 | KVM_FEATURE_NOP_IO_DELAY || 1 || not necessary to perform delays | ||
32 | || || on PIO operations. | ||
33 | ------------------------------------------------------------------------------ | ||
34 | KVM_FEATURE_MMU_OP || 2 || deprecated. | ||
35 | ------------------------------------------------------------------------------ | ||
36 | KVM_FEATURE_CLOCKSOURCE2 || 3 || kvmclock available at msrs | ||
37 | || || 0x4b564d00 and 0x4b564d01 | ||
38 | ------------------------------------------------------------------------------ | ||
39 | KVM_FEATURE_ASYNC_PF || 4 || async pf can be enabled by | ||
40 | || || writing to msr 0x4b564d02 | ||
41 | ------------------------------------------------------------------------------ | ||
42 | KVM_FEATURE_CLOCKSOURCE_STABLE_BIT || 24 || host will warn if no guest-side | ||
43 | || || per-cpu warps are expected in | ||
44 | || || kvmclock. | ||
45 | ------------------------------------------------------------------------------ | ||