HVS_CMD_SIZE
uint8_t pad[HVS_CMD_SIZE];
ccb->ccb_nsge, cmd, HVS_CMD_SIZE, ccb->ccb_rid);
rv = hv_channel_send(sc->sc_chan, cmd, HVS_CMD_SIZE,
memcpy(&ccb->ccb_rsp, ccb->ccb_cmd, HVS_CMD_SIZE);
memset(&ccb->ccb_rsp, 0, HVS_CMD_SIZE);