Merge remote-tracking branch 'remotes/mst/tags/for_upstream' into staging
[qemu.git] / migration / colo-failover.c
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 "qapi/error.h"
19 #include "qapi/qapi-commands-migration.h"
20 #include "qapi/qmp/qerror.h"
21 #include "qemu/error-report.h"
22 #include "trace.h"
23
24 static QEMUBH *failover_bh;
25 static FailoverStatus failover_state;
26
27 static void colo_failover_bh(void *opaque)
28 {
29 int old_state;
30
31 qemu_bh_delete(failover_bh);
32 failover_bh = NULL;
33
34 old_state = failover_set_state(FAILOVER_STATUS_REQUIRE,
35 FAILOVER_STATUS_ACTIVE);
36 if (old_state != FAILOVER_STATUS_REQUIRE) {
37 error_report("Unknown error for failover, old_state = %s",
38 FailoverStatus_str(old_state));
39 return;
40 }
41
42 colo_do_failover();
43 }
44
45 void failover_request_active(Error **errp)
46 {
47 if (failover_set_state(FAILOVER_STATUS_NONE,
48 FAILOVER_STATUS_REQUIRE) != FAILOVER_STATUS_NONE) {
49 error_setg(errp, "COLO failover is already actived");
50 return;
51 }
52 failover_bh = qemu_bh_new(colo_failover_bh, NULL);
53 qemu_bh_schedule(failover_bh);
54 }
55
56 void failover_init_state(void)
57 {
58 failover_state = FAILOVER_STATUS_NONE;
59 }
60
61 FailoverStatus failover_set_state(FailoverStatus old_state,
62 FailoverStatus new_state)
63 {
64 FailoverStatus old;
65
66 old = atomic_cmpxchg(&failover_state, old_state, new_state);
67 if (old == old_state) {
68 trace_colo_failover_set_state(FailoverStatus_str(new_state));
69 }
70 return old;
71 }
72
73 FailoverStatus failover_get_state(void)
74 {
75 return atomic_read(&failover_state);
76 }
77
78 void qmp_x_colo_lost_heartbeat(Error **errp)
79 {
80 if (get_colo_mode() == COLO_MODE_NONE) {
81 error_setg(errp, QERR_FEATURE_DISABLED, "colo");
82 return;
83 }
84
85 failover_request_active(errp);
86 }