[libvirt] Exploring linbvirt.

hi, i am started to exploring libvirt. i am using the version libvirt-1.1.3 and i want to know (or) find the path how the libvirt is creating VM with xen (libxl) in the source. Any guide or reference is available for this. How i can find the path of calling sequence for other operations(api). Guide me to get some idea on debugging the libvirt. Regards, cooldharma06