1 /* 2 * COarse-grain LOck-stepping Virtual Machines for Non-stop Service (COLO) 3 * (a.k.a. Fault Tolerance or Continuous Replication) 4 * 5 * Copyright (c) 2016 HUAWEI TECHNOLOGIES CO., LTD. 6 * Copyright (c) 2016 FUJITSU LIMITED 7 * Copyright (c) 2016 Intel Corporation 8 * 9 * This work is licensed under the terms of the GNU GPL, version 2 or 10 * later. See the COPYING file in the top-level directory. 11 */ 12 13 #include "qemu/osdep.h" 14 #include "migration/colo.h" 15 #include "migration/failover.h" 16 #include "qemu/main-loop.h" 17 #include "migration.h" 18 #include "qmp-commands.h" 19 #include "qapi/qmp/qerror.h" 20 #include "qemu/error-report.h" 21 #include "trace.h" 22 23 static QEMUBH *failover_bh; 24 static FailoverStatus failover_state; 25 26 static void colo_failover_bh(void *opaque) 27 { 28 int old_state; 29 30 qemu_bh_delete(failover_bh); 31 failover_bh = NULL; 32 33 old_state = failover_set_state(FAILOVER_STATUS_REQUIRE, 34 FAILOVER_STATUS_ACTIVE); 35 if (old_state != FAILOVER_STATUS_REQUIRE) { 36 error_report("Unknown error for failover, old_state = %s", 37 FailoverStatus_lookup[old_state]); 38 return; 39 } 40 41 colo_do_failover(NULL); 42 } 43 44 void failover_request_active(Error **errp) 45 { 46 if (failover_set_state(FAILOVER_STATUS_NONE, 47 FAILOVER_STATUS_REQUIRE) != FAILOVER_STATUS_NONE) { 48 error_setg(errp, "COLO failover is already actived"); 49 return; 50 } 51 failover_bh = qemu_bh_new(colo_failover_bh, NULL); 52 qemu_bh_schedule(failover_bh); 53 } 54 55 void failover_init_state(void) 56 { 57 failover_state = FAILOVER_STATUS_NONE; 58 } 59 60 FailoverStatus failover_set_state(FailoverStatus old_state, 61 FailoverStatus new_state) 62 { 63 FailoverStatus old; 64 65 old = atomic_cmpxchg(&failover_state, old_state, new_state); 66 if (old == old_state) { 67 trace_colo_failover_set_state(FailoverStatus_lookup[new_state]); 68 } 69 return old; 70 } 71 72 FailoverStatus failover_get_state(void) 73 { 74 return atomic_read(&failover_state); 75 } 76 77 void qmp_x_colo_lost_heartbeat(Error **errp) 78 { 79 if (get_colo_mode() == COLO_MODE_UNKNOWN) { 80 error_setg(errp, QERR_FEATURE_DISABLED, "colo"); 81 return; 82 } 83 84 failover_request_active(errp); 85 } 86