grant_handle_t handle, void *vaddr);
int xenbus_alloc_evtchn(struct xenbus_device *dev, int *port);
-int xenbus_bind_evtchn(struct xenbus_device *dev, int remote_port, int *port);
int xenbus_free_evtchn(struct xenbus_device *dev, int port);
enum xenbus_state xenbus_read_driver_state(const char *path);