[libvirt] inquiry, get native capabilities of the host

[Dong-In David Kang <dkang isi edu>]

 Hello,

 I'm interested in getting native capabilities of host CPU using libvirt.
I've looked at .../src/cpu/cpu_map.xml.
And it does describe native capabilities of host CPU very well. 
But, libvirt always returns a subset of the native capabilities which is far different from the feature lists in the xml file.
(I'm testing with <model name='Westmere'>.)
The sponsor of my project is interested is high-performance computing. 
And knowing native feature of the host CPU that can also be available to a virtual machine is very important for performance reason.

 I couldn't find how to get the native features of the host that is described in .../src/cpu/cpu_map.xml.
Is there a way or libvirt API to get the native capabilities of host CPU that is well described in .../src/cpu/cpu_map.xml?

 Thanks,

 David.