[libvirt] cpu flags

[Ben Guthro]

> I think the most likely place for exposing CPU flags would be in the
> capabilities XML format. We do in fact already expose 3 flags there,
> PAE, VMX and SVM. 

This looks like all of the info that I need - I guess I overlooked this part of the code prior to my message. 

The problem that I see currently is that despite the capabilities string containing the "host" tag, with this cpu info - it is up to each hypervisor driver to implement the broadcasting of host features.

For example - Xen will report PAE,VMX,SVM - but my ovirt node running KVM currently only reports the following:

  <host>
    <cpu>
      <arch>x86_64</arch>
    </cpu>
  </host>

It seems to me that it might be useful for some sort of "node" info driver, where we might be able to share code for hypervisor independent info about the physical machine it is running on. 

We should not have to re-write the scanning of /proc/cpuinfo in every hypervisor driver, IMHO.

Ben