Thanks , Hahn!
 
 
I think I get your point ,libvirt or the host machine is independent from the guest OS.
 
but ,as I know ,on the VMware ESX server , they supply an extra tool called vmware-tools which can get more information
 
about the Guest OS,including the network info. How did they do this?
 
Now I had to  write a tool to get more information about the active Guest OS using KVM hypervisor , have no idea how to
 
who can help me ?
 
Sincerely
 
wade