[libvirt] Exposing some unique features?

Hi, Though libvirt tries very hard to hide the difference between hypervisors behind an abstraction layer, there are still differences that we might want to expose to the users. For example, QEMU has the monitor interface, which provides some unique functions. Users might want to have access to the monitor interface and send command to it (like "gdbserver" command?). So how can we expose such information? We can have a new driver function, which return an opaque structure. The content of the structure is of course depends on the hypervisor type. One problem is that this might be dangerous if users relies on the QEMU monitor to execute some functions that should be done under control. Idea? Thanks, Quynh