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 "sysemu/sysemu.h"
15 #include "qapi/error.h"
16 #include "qapi/qapi-commands-migration.h"
17 #include "migration.h"
18 #include "qemu-file.h"
19 #include "savevm.h"
20 #include "migration/colo.h"
21 #include "io/channel-buffer.h"
22 #include "trace.h"
23 #include "qemu/error-report.h"
24 #include "qemu/main-loop.h"
25 #include "qemu/rcu.h"
26 #include "migration/failover.h"
27 #include "migration/ram.h"
28 #include "block/replication.h"
29 #include "net/colo-compare.h"
30 #include "net/colo.h"
31 #include "block/block.h"
32 #include "qapi/qapi-events-migration.h"
33 #include "sysemu/cpus.h"
34 #include "sysemu/runstate.h"
35 #include "net/filter.h"
36 #include "options.h"
37
38 static bool vmstate_loading;
39 static Notifier packets_compare_notifier;
40
41 /* User need to know colo mode after COLO failover */
42 static COLOMode last_colo_mode;
43
44 #define COLO_BUFFER_BASE_SIZE (4 * 1024 * 1024)
45
migration_in_colo_state(void)46 bool migration_in_colo_state(void)
47 {
48 MigrationState *s = migrate_get_current();
49
50 return (s->state == MIGRATION_STATUS_COLO);
51 }
52
migration_incoming_in_colo_state(void)53 bool migration_incoming_in_colo_state(void)
54 {
55 MigrationIncomingState *mis = migration_incoming_get_current();
56
57 return mis && (mis->state == MIGRATION_STATUS_COLO);
58 }
59
colo_runstate_is_stopped(void)60 static bool colo_runstate_is_stopped(void)
61 {
62 return runstate_check(RUN_STATE_COLO) || !runstate_is_running();
63 }
64
colo_checkpoint_notify(void)65 static void colo_checkpoint_notify(void)
66 {
67 MigrationState *s = migrate_get_current();
68 int64_t next_notify_time;
69
70 qemu_event_set(&s->colo_checkpoint_event);
71 s->colo_checkpoint_time = qemu_clock_get_ms(QEMU_CLOCK_HOST);
72 next_notify_time = s->colo_checkpoint_time + migrate_checkpoint_delay();
73 timer_mod(s->colo_delay_timer, next_notify_time);
74 }
75
colo_checkpoint_notify_timer(void * opaque)76 static void colo_checkpoint_notify_timer(void *opaque)
77 {
78 colo_checkpoint_notify();
79 }
80
colo_checkpoint_delay_set(void)81 void colo_checkpoint_delay_set(void)
82 {
83 if (migration_in_colo_state()) {
84 colo_checkpoint_notify();
85 }
86 }
87
secondary_vm_do_failover(void)88 static void secondary_vm_do_failover(void)
89 {
90 /* COLO needs enable block-replication */
91 int old_state;
92 MigrationIncomingState *mis = migration_incoming_get_current();
93 Error *local_err = NULL;
94
95 /* Can not do failover during the process of VM's loading VMstate, Or
96 * it will break the secondary VM.
97 */
98 if (vmstate_loading) {
99 old_state = failover_set_state(FAILOVER_STATUS_ACTIVE,
100 FAILOVER_STATUS_RELAUNCH);
101 if (old_state != FAILOVER_STATUS_ACTIVE) {
102 error_report("Unknown error while do failover for secondary VM,"
103 "old_state: %s", FailoverStatus_str(old_state));
104 }
105 return;
106 }
107
108 migrate_set_state(&mis->state, MIGRATION_STATUS_COLO,
109 MIGRATION_STATUS_COMPLETED);
110
111 replication_stop_all(true, &local_err);
112 if (local_err) {
113 error_report_err(local_err);
114 local_err = NULL;
115 }
116
117 /* Notify all filters of all NIC to do checkpoint */
118 colo_notify_filters_event(COLO_EVENT_FAILOVER, &local_err);
119 if (local_err) {
120 error_report_err(local_err);
121 }
122
123 if (!autostart) {
124 error_report("\"-S\" qemu option will be ignored in secondary side");
125 /* recover runstate to normal migration finish state */
126 autostart = true;
127 }
128 /*
129 * Make sure COLO incoming thread not block in recv or send,
130 * If mis->from_src_file and mis->to_src_file use the same fd,
131 * The second shutdown() will return -1, we ignore this value,
132 * It is harmless.
133 */
134 if (mis->from_src_file) {
135 qemu_file_shutdown(mis->from_src_file);
136 }
137 if (mis->to_src_file) {
138 qemu_file_shutdown(mis->to_src_file);
139 }
140
141 old_state = failover_set_state(FAILOVER_STATUS_ACTIVE,
142 FAILOVER_STATUS_COMPLETED);
143 if (old_state != FAILOVER_STATUS_ACTIVE) {
144 error_report("Incorrect state (%s) while doing failover for "
145 "secondary VM", FailoverStatus_str(old_state));
146 return;
147 }
148 /* Notify COLO incoming thread that failover work is finished */
149 qemu_sem_post(&mis->colo_incoming_sem);
150
151 /* For Secondary VM, jump to incoming co */
152 if (mis->colo_incoming_co) {
153 qemu_coroutine_enter(mis->colo_incoming_co);
154 }
155 }
156
primary_vm_do_failover(void)157 static void primary_vm_do_failover(void)
158 {
159 MigrationState *s = migrate_get_current();
160 int old_state;
161 Error *local_err = NULL;
162
163 migrate_set_state(&s->state, MIGRATION_STATUS_COLO,
164 MIGRATION_STATUS_COMPLETED);
165 /*
166 * kick COLO thread which might wait at
167 * qemu_sem_wait(&s->colo_checkpoint_sem).
168 */
169 colo_checkpoint_notify();
170
171 /*
172 * Wake up COLO thread which may blocked in recv() or send(),
173 * The s->rp_state.from_dst_file and s->to_dst_file may use the
174 * same fd, but we still shutdown the fd for twice, it is harmless.
175 */
176 if (s->to_dst_file) {
177 qemu_file_shutdown(s->to_dst_file);
178 }
179 if (s->rp_state.from_dst_file) {
180 qemu_file_shutdown(s->rp_state.from_dst_file);
181 }
182
183 old_state = failover_set_state(FAILOVER_STATUS_ACTIVE,
184 FAILOVER_STATUS_COMPLETED);
185 if (old_state != FAILOVER_STATUS_ACTIVE) {
186 error_report("Incorrect state (%s) while doing failover for Primary VM",
187 FailoverStatus_str(old_state));
188 return;
189 }
190
191 replication_stop_all(true, &local_err);
192 if (local_err) {
193 error_report_err(local_err);
194 local_err = NULL;
195 }
196
197 /* Notify COLO thread that failover work is finished */
198 qemu_sem_post(&s->colo_exit_sem);
199 }
200
get_colo_mode(void)201 COLOMode get_colo_mode(void)
202 {
203 if (migration_in_colo_state()) {
204 return COLO_MODE_PRIMARY;
205 } else if (migration_incoming_in_colo_state()) {
206 return COLO_MODE_SECONDARY;
207 } else {
208 return COLO_MODE_NONE;
209 }
210 }
211
colo_do_failover(void)212 void colo_do_failover(void)
213 {
214 /* Make sure VM stopped while failover happened. */
215 if (!colo_runstate_is_stopped()) {
216 vm_stop_force_state(RUN_STATE_COLO);
217 }
218
219 switch (last_colo_mode = get_colo_mode()) {
220 case COLO_MODE_PRIMARY:
221 primary_vm_do_failover();
222 break;
223 case COLO_MODE_SECONDARY:
224 secondary_vm_do_failover();
225 break;
226 default:
227 error_report("colo_do_failover failed because the colo mode"
228 " could not be obtained");
229 }
230 }
231
qmp_xen_set_replication(bool enable,bool primary,bool has_failover,bool failover,Error ** errp)232 void qmp_xen_set_replication(bool enable, bool primary,
233 bool has_failover, bool failover,
234 Error **errp)
235 {
236 ReplicationMode mode = primary ?
237 REPLICATION_MODE_PRIMARY :
238 REPLICATION_MODE_SECONDARY;
239
240 if (has_failover && enable) {
241 error_setg(errp, "Parameter 'failover' is only for"
242 " stopping replication");
243 return;
244 }
245
246 if (enable) {
247 replication_start_all(mode, errp);
248 } else {
249 if (!has_failover) {
250 failover = NULL;
251 }
252 replication_stop_all(failover, failover ? NULL : errp);
253 }
254 }
255
qmp_query_xen_replication_status(Error ** errp)256 ReplicationStatus *qmp_query_xen_replication_status(Error **errp)
257 {
258 Error *err = NULL;
259 ReplicationStatus *s = g_new0(ReplicationStatus, 1);
260
261 replication_get_error_all(&err);
262 if (err) {
263 s->error = true;
264 s->desc = g_strdup(error_get_pretty(err));
265 } else {
266 s->error = false;
267 }
268
269 error_free(err);
270 return s;
271 }
272
qmp_xen_colo_do_checkpoint(Error ** errp)273 void qmp_xen_colo_do_checkpoint(Error **errp)
274 {
275 Error *err = NULL;
276
277 replication_do_checkpoint_all(&err);
278 if (err) {
279 error_propagate(errp, err);
280 return;
281 }
282 /* Notify all filters of all NIC to do checkpoint */
283 colo_notify_filters_event(COLO_EVENT_CHECKPOINT, errp);
284 }
285
qmp_query_colo_status(Error ** errp)286 COLOStatus *qmp_query_colo_status(Error **errp)
287 {
288 COLOStatus *s = g_new0(COLOStatus, 1);
289
290 s->mode = get_colo_mode();
291 s->last_mode = last_colo_mode;
292
293 switch (failover_get_state()) {
294 case FAILOVER_STATUS_NONE:
295 s->reason = COLO_EXIT_REASON_NONE;
296 break;
297 case FAILOVER_STATUS_COMPLETED:
298 s->reason = COLO_EXIT_REASON_REQUEST;
299 break;
300 default:
301 if (migration_in_colo_state()) {
302 s->reason = COLO_EXIT_REASON_PROCESSING;
303 } else {
304 s->reason = COLO_EXIT_REASON_ERROR;
305 }
306 }
307
308 return s;
309 }
310
colo_send_message(QEMUFile * f,COLOMessage msg,Error ** errp)311 static void colo_send_message(QEMUFile *f, COLOMessage msg,
312 Error **errp)
313 {
314 int ret;
315
316 if (msg >= COLO_MESSAGE__MAX) {
317 error_setg(errp, "%s: Invalid message", __func__);
318 return;
319 }
320 qemu_put_be32(f, msg);
321 ret = qemu_fflush(f);
322 if (ret < 0) {
323 error_setg_errno(errp, -ret, "Can't send COLO message");
324 }
325 trace_colo_send_message(COLOMessage_str(msg));
326 }
327
colo_send_message_value(QEMUFile * f,COLOMessage msg,uint64_t value,Error ** errp)328 static void colo_send_message_value(QEMUFile *f, COLOMessage msg,
329 uint64_t value, Error **errp)
330 {
331 Error *local_err = NULL;
332 int ret;
333
334 colo_send_message(f, msg, &local_err);
335 if (local_err) {
336 error_propagate(errp, local_err);
337 return;
338 }
339 qemu_put_be64(f, value);
340 ret = qemu_fflush(f);
341 if (ret < 0) {
342 error_setg_errno(errp, -ret, "Failed to send value for message:%s",
343 COLOMessage_str(msg));
344 }
345 }
346
colo_receive_message(QEMUFile * f,Error ** errp)347 static COLOMessage colo_receive_message(QEMUFile *f, Error **errp)
348 {
349 COLOMessage msg;
350 int ret;
351
352 msg = qemu_get_be32(f);
353 ret = qemu_file_get_error(f);
354 if (ret < 0) {
355 error_setg_errno(errp, -ret, "Can't receive COLO message");
356 return msg;
357 }
358 if (msg >= COLO_MESSAGE__MAX) {
359 error_setg(errp, "%s: Invalid message", __func__);
360 return msg;
361 }
362 trace_colo_receive_message(COLOMessage_str(msg));
363 return msg;
364 }
365
colo_receive_check_message(QEMUFile * f,COLOMessage expect_msg,Error ** errp)366 static void colo_receive_check_message(QEMUFile *f, COLOMessage expect_msg,
367 Error **errp)
368 {
369 COLOMessage msg;
370 Error *local_err = NULL;
371
372 msg = colo_receive_message(f, &local_err);
373 if (local_err) {
374 error_propagate(errp, local_err);
375 return;
376 }
377 if (msg != expect_msg) {
378 error_setg(errp, "Unexpected COLO message %d, expected %d",
379 msg, expect_msg);
380 }
381 }
382
colo_receive_message_value(QEMUFile * f,uint32_t expect_msg,Error ** errp)383 static uint64_t colo_receive_message_value(QEMUFile *f, uint32_t expect_msg,
384 Error **errp)
385 {
386 Error *local_err = NULL;
387 uint64_t value;
388 int ret;
389
390 colo_receive_check_message(f, expect_msg, &local_err);
391 if (local_err) {
392 error_propagate(errp, local_err);
393 return 0;
394 }
395
396 value = qemu_get_be64(f);
397 ret = qemu_file_get_error(f);
398 if (ret < 0) {
399 error_setg_errno(errp, -ret, "Failed to get value for COLO message: %s",
400 COLOMessage_str(expect_msg));
401 }
402 return value;
403 }
404
colo_do_checkpoint_transaction(MigrationState * s,QIOChannelBuffer * bioc,QEMUFile * fb)405 static int colo_do_checkpoint_transaction(MigrationState *s,
406 QIOChannelBuffer *bioc,
407 QEMUFile *fb)
408 {
409 Error *local_err = NULL;
410 int ret = -1;
411
412 colo_send_message(s->to_dst_file, COLO_MESSAGE_CHECKPOINT_REQUEST,
413 &local_err);
414 if (local_err) {
415 goto out;
416 }
417
418 colo_receive_check_message(s->rp_state.from_dst_file,
419 COLO_MESSAGE_CHECKPOINT_REPLY, &local_err);
420 if (local_err) {
421 goto out;
422 }
423 /* Reset channel-buffer directly */
424 qio_channel_io_seek(QIO_CHANNEL(bioc), 0, 0, NULL);
425 bioc->usage = 0;
426
427 bql_lock();
428 if (failover_get_state() != FAILOVER_STATUS_NONE) {
429 bql_unlock();
430 goto out;
431 }
432 vm_stop_force_state(RUN_STATE_COLO);
433 bql_unlock();
434 trace_colo_vm_state_change("run", "stop");
435 /*
436 * Failover request bh could be called after vm_stop_force_state(),
437 * So we need check failover_request_is_active() again.
438 */
439 if (failover_get_state() != FAILOVER_STATUS_NONE) {
440 goto out;
441 }
442 bql_lock();
443
444 replication_do_checkpoint_all(&local_err);
445 if (local_err) {
446 bql_unlock();
447 goto out;
448 }
449
450 colo_send_message(s->to_dst_file, COLO_MESSAGE_VMSTATE_SEND, &local_err);
451 if (local_err) {
452 bql_unlock();
453 goto out;
454 }
455 /* Note: device state is saved into buffer */
456 ret = qemu_save_device_state(fb);
457
458 bql_unlock();
459 if (ret < 0) {
460 goto out;
461 }
462
463 if (migrate_auto_converge()) {
464 mig_throttle_counter_reset();
465 }
466 /*
467 * Only save VM's live state, which not including device state.
468 * TODO: We may need a timeout mechanism to prevent COLO process
469 * to be blocked here.
470 */
471 qemu_savevm_live_state(s->to_dst_file);
472
473 qemu_fflush(fb);
474
475 /*
476 * We need the size of the VMstate data in Secondary side,
477 * With which we can decide how much data should be read.
478 */
479 colo_send_message_value(s->to_dst_file, COLO_MESSAGE_VMSTATE_SIZE,
480 bioc->usage, &local_err);
481 if (local_err) {
482 goto out;
483 }
484
485 qemu_put_buffer(s->to_dst_file, bioc->data, bioc->usage);
486 ret = qemu_fflush(s->to_dst_file);
487 if (ret < 0) {
488 goto out;
489 }
490
491 colo_receive_check_message(s->rp_state.from_dst_file,
492 COLO_MESSAGE_VMSTATE_RECEIVED, &local_err);
493 if (local_err) {
494 goto out;
495 }
496
497 qemu_event_reset(&s->colo_checkpoint_event);
498 colo_notify_compares_event(NULL, COLO_EVENT_CHECKPOINT, &local_err);
499 if (local_err) {
500 goto out;
501 }
502
503 colo_receive_check_message(s->rp_state.from_dst_file,
504 COLO_MESSAGE_VMSTATE_LOADED, &local_err);
505 if (local_err) {
506 goto out;
507 }
508
509 ret = 0;
510
511 bql_lock();
512 vm_start();
513 bql_unlock();
514 trace_colo_vm_state_change("stop", "run");
515
516 out:
517 if (local_err) {
518 error_report_err(local_err);
519 }
520 return ret;
521 }
522
colo_compare_notify_checkpoint(Notifier * notifier,void * data)523 static void colo_compare_notify_checkpoint(Notifier *notifier, void *data)
524 {
525 colo_checkpoint_notify();
526 }
527
colo_process_checkpoint(MigrationState * s)528 static void colo_process_checkpoint(MigrationState *s)
529 {
530 QIOChannelBuffer *bioc;
531 QEMUFile *fb = NULL;
532 Error *local_err = NULL;
533 int ret;
534
535 if (get_colo_mode() != COLO_MODE_PRIMARY) {
536 error_report("COLO mode must be COLO_MODE_PRIMARY");
537 return;
538 }
539
540 failover_init_state();
541
542 s->rp_state.from_dst_file = qemu_file_get_return_path(s->to_dst_file);
543 if (!s->rp_state.from_dst_file) {
544 error_report("Open QEMUFile from_dst_file failed");
545 goto out;
546 }
547
548 packets_compare_notifier.notify = colo_compare_notify_checkpoint;
549 colo_compare_register_notifier(&packets_compare_notifier);
550
551 /*
552 * Wait for Secondary finish loading VM states and enter COLO
553 * restore.
554 */
555 colo_receive_check_message(s->rp_state.from_dst_file,
556 COLO_MESSAGE_CHECKPOINT_READY, &local_err);
557 if (local_err) {
558 goto out;
559 }
560 bioc = qio_channel_buffer_new(COLO_BUFFER_BASE_SIZE);
561 fb = qemu_file_new_output(QIO_CHANNEL(bioc));
562 object_unref(OBJECT(bioc));
563
564 bql_lock();
565 replication_start_all(REPLICATION_MODE_PRIMARY, &local_err);
566 if (local_err) {
567 bql_unlock();
568 goto out;
569 }
570
571 vm_start();
572 bql_unlock();
573 trace_colo_vm_state_change("stop", "run");
574
575 timer_mod(s->colo_delay_timer, qemu_clock_get_ms(QEMU_CLOCK_HOST) +
576 migrate_checkpoint_delay());
577
578 while (s->state == MIGRATION_STATUS_COLO) {
579 if (failover_get_state() != FAILOVER_STATUS_NONE) {
580 error_report("failover request");
581 goto out;
582 }
583
584 qemu_event_wait(&s->colo_checkpoint_event);
585
586 if (s->state != MIGRATION_STATUS_COLO) {
587 goto out;
588 }
589 ret = colo_do_checkpoint_transaction(s, bioc, fb);
590 if (ret < 0) {
591 goto out;
592 }
593 }
594
595 out:
596 /* Throw the unreported error message after exited from loop */
597 if (local_err) {
598 error_report_err(local_err);
599 }
600
601 if (fb) {
602 qemu_fclose(fb);
603 }
604
605 /*
606 * There are only two reasons we can get here, some error happened
607 * or the user triggered failover.
608 */
609 switch (failover_get_state()) {
610 case FAILOVER_STATUS_COMPLETED:
611 qapi_event_send_colo_exit(COLO_MODE_PRIMARY,
612 COLO_EXIT_REASON_REQUEST);
613 break;
614 default:
615 qapi_event_send_colo_exit(COLO_MODE_PRIMARY,
616 COLO_EXIT_REASON_ERROR);
617 }
618
619 /* Hope this not to be too long to wait here */
620 qemu_sem_wait(&s->colo_exit_sem);
621 qemu_sem_destroy(&s->colo_exit_sem);
622
623 /*
624 * It is safe to unregister notifier after failover finished.
625 * Besides, colo_delay_timer and colo_checkpoint_sem can't be
626 * released before unregister notifier, or there will be use-after-free
627 * error.
628 */
629 colo_compare_unregister_notifier(&packets_compare_notifier);
630 timer_free(s->colo_delay_timer);
631 qemu_event_destroy(&s->colo_checkpoint_event);
632
633 /*
634 * Must be called after failover BH is completed,
635 * Or the failover BH may shutdown the wrong fd that
636 * re-used by other threads after we release here.
637 */
638 if (s->rp_state.from_dst_file) {
639 qemu_fclose(s->rp_state.from_dst_file);
640 s->rp_state.from_dst_file = NULL;
641 }
642 }
643
migrate_start_colo_process(MigrationState * s)644 void migrate_start_colo_process(MigrationState *s)
645 {
646 bql_unlock();
647 qemu_event_init(&s->colo_checkpoint_event, false);
648 s->colo_delay_timer = timer_new_ms(QEMU_CLOCK_HOST,
649 colo_checkpoint_notify_timer, NULL);
650
651 qemu_sem_init(&s->colo_exit_sem, 0);
652 colo_process_checkpoint(s);
653 bql_lock();
654 }
655
colo_incoming_process_checkpoint(MigrationIncomingState * mis,QEMUFile * fb,QIOChannelBuffer * bioc,Error ** errp)656 static void colo_incoming_process_checkpoint(MigrationIncomingState *mis,
657 QEMUFile *fb, QIOChannelBuffer *bioc, Error **errp)
658 {
659 uint64_t total_size;
660 uint64_t value;
661 Error *local_err = NULL;
662 int ret;
663
664 bql_lock();
665 vm_stop_force_state(RUN_STATE_COLO);
666 bql_unlock();
667 trace_colo_vm_state_change("run", "stop");
668
669 /* FIXME: This is unnecessary for periodic checkpoint mode */
670 colo_send_message(mis->to_src_file, COLO_MESSAGE_CHECKPOINT_REPLY,
671 &local_err);
672 if (local_err) {
673 error_propagate(errp, local_err);
674 return;
675 }
676
677 colo_receive_check_message(mis->from_src_file,
678 COLO_MESSAGE_VMSTATE_SEND, &local_err);
679 if (local_err) {
680 error_propagate(errp, local_err);
681 return;
682 }
683
684 bql_lock();
685 cpu_synchronize_all_states();
686 ret = qemu_loadvm_state_main(mis->from_src_file, mis);
687 bql_unlock();
688
689 if (ret < 0) {
690 error_setg(errp, "Load VM's live state (ram) error");
691 return;
692 }
693
694 value = colo_receive_message_value(mis->from_src_file,
695 COLO_MESSAGE_VMSTATE_SIZE, &local_err);
696 if (local_err) {
697 error_propagate(errp, local_err);
698 return;
699 }
700
701 /*
702 * Read VM device state data into channel buffer,
703 * It's better to re-use the memory allocated.
704 * Here we need to handle the channel buffer directly.
705 */
706 if (value > bioc->capacity) {
707 bioc->capacity = value;
708 bioc->data = g_realloc(bioc->data, bioc->capacity);
709 }
710 total_size = qemu_get_buffer(mis->from_src_file, bioc->data, value);
711 if (total_size != value) {
712 error_setg(errp, "Got %" PRIu64 " VMState data, less than expected"
713 " %" PRIu64, total_size, value);
714 return;
715 }
716 bioc->usage = total_size;
717 qio_channel_io_seek(QIO_CHANNEL(bioc), 0, 0, NULL);
718
719 colo_send_message(mis->to_src_file, COLO_MESSAGE_VMSTATE_RECEIVED,
720 &local_err);
721 if (local_err) {
722 error_propagate(errp, local_err);
723 return;
724 }
725
726 bql_lock();
727 vmstate_loading = true;
728 colo_flush_ram_cache();
729 ret = qemu_load_device_state(fb);
730 if (ret < 0) {
731 error_setg(errp, "COLO: load device state failed");
732 vmstate_loading = false;
733 bql_unlock();
734 return;
735 }
736
737 replication_get_error_all(&local_err);
738 if (local_err) {
739 error_propagate(errp, local_err);
740 vmstate_loading = false;
741 bql_unlock();
742 return;
743 }
744
745 /* discard colo disk buffer */
746 replication_do_checkpoint_all(&local_err);
747 if (local_err) {
748 error_propagate(errp, local_err);
749 vmstate_loading = false;
750 bql_unlock();
751 return;
752 }
753 /* Notify all filters of all NIC to do checkpoint */
754 colo_notify_filters_event(COLO_EVENT_CHECKPOINT, &local_err);
755
756 if (local_err) {
757 error_propagate(errp, local_err);
758 vmstate_loading = false;
759 bql_unlock();
760 return;
761 }
762
763 vmstate_loading = false;
764 vm_start();
765 bql_unlock();
766 trace_colo_vm_state_change("stop", "run");
767
768 if (failover_get_state() == FAILOVER_STATUS_RELAUNCH) {
769 return;
770 }
771
772 colo_send_message(mis->to_src_file, COLO_MESSAGE_VMSTATE_LOADED,
773 &local_err);
774 error_propagate(errp, local_err);
775 }
776
colo_wait_handle_message(MigrationIncomingState * mis,QEMUFile * fb,QIOChannelBuffer * bioc,Error ** errp)777 static void colo_wait_handle_message(MigrationIncomingState *mis,
778 QEMUFile *fb, QIOChannelBuffer *bioc, Error **errp)
779 {
780 COLOMessage msg;
781 Error *local_err = NULL;
782
783 msg = colo_receive_message(mis->from_src_file, &local_err);
784 if (local_err) {
785 error_propagate(errp, local_err);
786 return;
787 }
788
789 switch (msg) {
790 case COLO_MESSAGE_CHECKPOINT_REQUEST:
791 colo_incoming_process_checkpoint(mis, fb, bioc, errp);
792 break;
793 default:
794 error_setg(errp, "Got unknown COLO message: %d", msg);
795 break;
796 }
797 }
798
colo_shutdown(void)799 void colo_shutdown(void)
800 {
801 MigrationIncomingState *mis = NULL;
802 MigrationState *s = NULL;
803
804 switch (get_colo_mode()) {
805 case COLO_MODE_PRIMARY:
806 s = migrate_get_current();
807 qemu_event_set(&s->colo_checkpoint_event);
808 qemu_sem_post(&s->colo_exit_sem);
809 break;
810 case COLO_MODE_SECONDARY:
811 mis = migration_incoming_get_current();
812 qemu_sem_post(&mis->colo_incoming_sem);
813 break;
814 default:
815 break;
816 }
817 }
818
colo_process_incoming_thread(void * opaque)819 static void *colo_process_incoming_thread(void *opaque)
820 {
821 MigrationIncomingState *mis = opaque;
822 QEMUFile *fb = NULL;
823 QIOChannelBuffer *bioc = NULL; /* Cache incoming device state */
824 Error *local_err = NULL;
825
826 rcu_register_thread();
827 qemu_sem_init(&mis->colo_incoming_sem, 0);
828
829 migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE,
830 MIGRATION_STATUS_COLO);
831
832 if (get_colo_mode() != COLO_MODE_SECONDARY) {
833 error_report("COLO mode must be COLO_MODE_SECONDARY");
834 return NULL;
835 }
836
837 /* Make sure all file formats throw away their mutable metadata */
838 bql_lock();
839 bdrv_activate_all(&local_err);
840 bql_unlock();
841 if (local_err) {
842 error_report_err(local_err);
843 return NULL;
844 }
845
846 failover_init_state();
847
848 mis->to_src_file = qemu_file_get_return_path(mis->from_src_file);
849 if (!mis->to_src_file) {
850 error_report("COLO incoming thread: Open QEMUFile to_src_file failed");
851 goto out;
852 }
853 /*
854 * Note: the communication between Primary side and Secondary side
855 * should be sequential, we set the fd to unblocked in migration incoming
856 * coroutine, and here we are in the COLO incoming thread, so it is ok to
857 * set the fd back to blocked.
858 */
859 qemu_file_set_blocking(mis->from_src_file, true);
860
861 colo_incoming_start_dirty_log();
862
863 bioc = qio_channel_buffer_new(COLO_BUFFER_BASE_SIZE);
864 fb = qemu_file_new_input(QIO_CHANNEL(bioc));
865 object_unref(OBJECT(bioc));
866
867 bql_lock();
868 replication_start_all(REPLICATION_MODE_SECONDARY, &local_err);
869 if (local_err) {
870 bql_unlock();
871 goto out;
872 }
873 vm_start();
874 bql_unlock();
875 trace_colo_vm_state_change("stop", "run");
876
877 colo_send_message(mis->to_src_file, COLO_MESSAGE_CHECKPOINT_READY,
878 &local_err);
879 if (local_err) {
880 goto out;
881 }
882
883 while (mis->state == MIGRATION_STATUS_COLO) {
884 colo_wait_handle_message(mis, fb, bioc, &local_err);
885 if (local_err) {
886 error_report_err(local_err);
887 break;
888 }
889
890 if (failover_get_state() == FAILOVER_STATUS_RELAUNCH) {
891 failover_set_state(FAILOVER_STATUS_RELAUNCH,
892 FAILOVER_STATUS_NONE);
893 failover_request_active(NULL);
894 break;
895 }
896
897 if (failover_get_state() != FAILOVER_STATUS_NONE) {
898 error_report("failover request");
899 break;
900 }
901 }
902
903 out:
904 /*
905 * There are only two reasons we can get here, some error happened
906 * or the user triggered failover.
907 */
908 switch (failover_get_state()) {
909 case FAILOVER_STATUS_COMPLETED:
910 qapi_event_send_colo_exit(COLO_MODE_SECONDARY,
911 COLO_EXIT_REASON_REQUEST);
912 break;
913 default:
914 qapi_event_send_colo_exit(COLO_MODE_SECONDARY,
915 COLO_EXIT_REASON_ERROR);
916 }
917
918 if (fb) {
919 qemu_fclose(fb);
920 }
921
922 /* Hope this not to be too long to loop here */
923 qemu_sem_wait(&mis->colo_incoming_sem);
924 qemu_sem_destroy(&mis->colo_incoming_sem);
925
926 rcu_unregister_thread();
927 return NULL;
928 }
929
colo_incoming_co(void)930 void coroutine_fn colo_incoming_co(void)
931 {
932 MigrationIncomingState *mis = migration_incoming_get_current();
933 QemuThread th;
934
935 assert(bql_locked());
936 assert(migration_incoming_colo_enabled());
937
938 qemu_thread_create(&th, "mig/dst/colo", colo_process_incoming_thread,
939 mis, QEMU_THREAD_JOINABLE);
940
941 mis->colo_incoming_co = qemu_coroutine_self();
942 qemu_coroutine_yield();
943 mis->colo_incoming_co = NULL;
944
945 bql_unlock();
946 /* Wait checkpoint incoming thread exit before free resource */
947 qemu_thread_join(&th);
948 bql_lock();
949
950 /* We hold the global BQL, so it is safe here */
951 colo_release_ram_cache();
952 }
953