On 04/22/2013 01:00 PM, Eduardo Habkost wrote:
This property will be useful for libvirt, as libvirt already has
logic
based on low-level feature bits (not feature names), so it will be
really easy to convert the current libvirt logic to something using the
"feature-words" property.
The property will have two main use cases:
- Checking host capabilities, by checking the features of the "host"
CPU model
- Checking which features are enabled on each CPU model
Example output:
$ ./QMP/qmp --path=/tmp/m qom-get --path=/machine/unattached/device[1]
--property=feature-words
If I'm not mistaken, the QMP counterpart that libvirt will use is:
{ "execute":"qom-get",
"arguments": { "path":"/machine/unattached/device[1]",
"property":"feature-words" } }
item[0].cpuid-register: EDX
item[0].cpuid-input-eax: 2147483658
item[0].features: 0
item[1].cpuid-register: EAX
item[1].cpuid-input-eax: 1073741825
item[1].features: 0
item[2].cpuid-register: EDX
item[2].cpuid-input-eax: 3221225473
item[2].features: 0
item[3].cpuid-register: ECX
item[3].cpuid-input-eax: 2147483649
item[3].features: 101
item[4].cpuid-register: EDX
item[4].cpuid-input-eax: 2147483649
item[4].features: 563346425
item[5].cpuid-register: EBX
item[5].cpuid-input-eax: 7
item[5].features: 0
item[5].cpuid-input-ecx: 0
item[6].cpuid-register: ECX
item[6].cpuid-input-eax: 1
item[6].features: 2155880449
item[7].cpuid-register: EDX
item[7].cpuid-input-eax: 1
item[7].features: 126614521
And this would then be returned as a JSON array containing struct
members looking like this:
+{ 'type': 'X86CPUFeatureWordInfo',
+ 'data': { 'cpuid-input-eax': 'int',
+ '*cpuid-input-ecx': 'int',
+ 'cpuid-register': 'X86CPURegister32',
+ 'features': 'int' } }
Looks reasonable (and better than what we've had in the past!), although
I'll let Jiri Denemark give final say on whether it meets libvirt's needs.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library
http://libvirt.org