xen_device
struct xen_device *xdv;
xdv = malloc(sizeof(struct xen_device), M_DEVBUF, M_ZERO | M_NOWAIT);
struct xen_device *xdv, *xvdn;
free(xdv, M_DEVBUF, sizeof(struct xen_device));
LIST_ENTRY(xen_device) dv_entry;
LIST_HEAD(xen_devices, xen_device);