time_travel_ext_req
time_travel_ext_req(UM_TIMETRAVEL_BROADCAST, bc_message);
time_travel_ext_req(UM_TIMETRAVEL_REQUEST, time);
time_travel_ext_req(UM_TIMETRAVEL_UPDATE, time_travel_time);
time_travel_ext_req(UM_TIMETRAVEL_WAIT, -1);
time_travel_ext_req(UM_TIMETRAVEL_GET, -1);
time_travel_ext_req(UM_TIMETRAVEL_START, id);
time_travel_start = time_travel_ext_req(UM_TIMETRAVEL_GET_TOD, -1);
extern u64 time_travel_ext_req(u32 op, u64 time);