[Libvir] How to get the memory used by a guest domin

["Pranay Prasoon" <pranay prasoon gmail com>]

Hi,
It appears to be no API available to provide the memory used by a guest domin.
I looked at the availble libvirt api called "virNodeGetCellsFreeMemory"
using which it is possible to get the free mem. But looking further I
found that this is free memory of the "whole box" rather than based
upon the guest domain.
How can I get the memory used by a guest domin.

Thanks n Regards,
-Pranay.