diff options
| author | Grant Likely <grant.likely@secretlab.ca> | 2010-05-22 00:36:56 -0600 |
|---|---|---|
| committer | Grant Likely <grant.likely@secretlab.ca> | 2010-05-22 00:36:56 -0600 |
| commit | cf9b59e9d3e008591d1f54830f570982bb307a0d (patch) | |
| tree | 113478ce8fd8c832ba726ffdf59b82cb46356476 /Documentation/kvm/cpuid.txt | |
| parent | 44504b2bebf8b5823c59484e73096a7d6574471d (diff) | |
| parent | f4b87dee923342505e1ddba8d34ce9de33e75050 (diff) | |
Merge remote branch 'origin' into secretlab/next-devicetree
Merging in current state of Linus' tree to deal with merge conflicts and
build failures in vio.c after merge.
Conflicts:
drivers/i2c/busses/i2c-cpm.c
drivers/i2c/busses/i2c-mpc.c
drivers/net/gianfar.c
Also fixed up one line in arch/powerpc/kernel/vio.c to use the
correct node pointer.
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Diffstat (limited to 'Documentation/kvm/cpuid.txt')
| -rw-r--r-- | Documentation/kvm/cpuid.txt | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/Documentation/kvm/cpuid.txt b/Documentation/kvm/cpuid.txt new file mode 100644 index 00000000000..14a12ea92b7 --- /dev/null +++ b/Documentation/kvm/cpuid.txt @@ -0,0 +1,42 @@ +KVM CPUID bits +Glauber Costa <glommer@redhat.com>, Red Hat Inc, 2010 +===================================================== + +A guest running on a kvm host, can check some of its features using +cpuid. This is not always guaranteed to work, since userspace can +mask-out some, or even all KVM-related cpuid features before launching +a guest. + +KVM cpuid functions are: + +function: KVM_CPUID_SIGNATURE (0x40000000) +returns : eax = 0, + ebx = 0x4b4d564b, + ecx = 0x564b4d56, + edx = 0x4d. +Note that this value in ebx, ecx and edx corresponds to the string "KVMKVMKVM". +This function queries the presence of KVM cpuid leafs. + + +function: define KVM_CPUID_FEATURES (0x40000001) +returns : ebx, ecx, edx = 0 + eax = and OR'ed group of (1 << flag), where each flags is: + + +flag || value || meaning +============================================================================= +KVM_FEATURE_CLOCKSOURCE || 0 || kvmclock available at msrs + || || 0x11 and 0x12. +------------------------------------------------------------------------------ +KVM_FEATURE_NOP_IO_DELAY || 1 || not necessary to perform delays + || || on PIO operations. +------------------------------------------------------------------------------ +KVM_FEATURE_MMU_OP || 2 || deprecated. +------------------------------------------------------------------------------ +KVM_FEATURE_CLOCKSOURCE2 || 3 || kvmclock available at msrs + || || 0x4b564d00 and 0x4b564d01 +------------------------------------------------------------------------------ +KVM_FEATURE_CLOCKSOURCE_STABLE_BIT || 24 || host will warn if no guest-side + || || per-cpu warps are expected in + || || kvmclock. +------------------------------------------------------------------------------ |