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 "system/system.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 "system/cpus.h"
34 #include "system/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_event_set(&mis->colo_incoming_event);
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_event_set(&s->colo_exit_event);
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
456 qemu_savevm_maybe_send_switchover_start(s->to_dst_file);
457
458 /* Note: device state is saved into buffer */
459 ret = qemu_save_device_state(fb);
460
461 bql_unlock();
462 if (ret < 0) {
463 goto out;
464 }
465
466 if (migrate_auto_converge()) {
467 mig_throttle_counter_reset();
468 }
469 /*
470 * Only save VM's live state, which not including device state.
471 * TODO: We may need a timeout mechanism to prevent COLO process
472 * to be blocked here.
473 */
474 qemu_savevm_live_state(s->to_dst_file);
475
476 qemu_fflush(fb);
477
478 /*
479 * We need the size of the VMstate data in Secondary side,
480 * With which we can decide how much data should be read.
481 */
482 colo_send_message_value(s->to_dst_file, COLO_MESSAGE_VMSTATE_SIZE,
483 bioc->usage, &local_err);
484 if (local_err) {
485 goto out;
486 }
487
488 qemu_put_buffer(s->to_dst_file, bioc->data, bioc->usage);
489 ret = qemu_fflush(s->to_dst_file);
490 if (ret < 0) {
491 goto out;
492 }
493
494 colo_receive_check_message(s->rp_state.from_dst_file,
495 COLO_MESSAGE_VMSTATE_RECEIVED, &local_err);
496 if (local_err) {
497 goto out;
498 }
499
500 qemu_event_reset(&s->colo_checkpoint_event);
501 colo_notify_compares_event(NULL, COLO_EVENT_CHECKPOINT, &local_err);
502 if (local_err) {
503 goto out;
504 }
505
506 colo_receive_check_message(s->rp_state.from_dst_file,
507 COLO_MESSAGE_VMSTATE_LOADED, &local_err);
508 if (local_err) {
509 goto out;
510 }
511
512 ret = 0;
513
514 bql_lock();
515 vm_start();
516 bql_unlock();
517 trace_colo_vm_state_change("stop", "run");
518
519 out:
520 if (local_err) {
521 error_report_err(local_err);
522 }
523 return ret;
524 }
525
colo_compare_notify_checkpoint(Notifier * notifier,void * data)526 static void colo_compare_notify_checkpoint(Notifier *notifier, void *data)
527 {
528 colo_checkpoint_notify();
529 }
530
colo_process_checkpoint(MigrationState * s)531 static void colo_process_checkpoint(MigrationState *s)
532 {
533 QIOChannelBuffer *bioc;
534 QEMUFile *fb = NULL;
535 Error *local_err = NULL;
536 int ret;
537
538 if (get_colo_mode() != COLO_MODE_PRIMARY) {
539 error_report("COLO mode must be COLO_MODE_PRIMARY");
540 return;
541 }
542
543 failover_init_state();
544
545 s->rp_state.from_dst_file = qemu_file_get_return_path(s->to_dst_file);
546 if (!s->rp_state.from_dst_file) {
547 error_report("Open QEMUFile from_dst_file failed");
548 goto out;
549 }
550
551 packets_compare_notifier.notify = colo_compare_notify_checkpoint;
552 colo_compare_register_notifier(&packets_compare_notifier);
553
554 /*
555 * Wait for Secondary finish loading VM states and enter COLO
556 * restore.
557 */
558 colo_receive_check_message(s->rp_state.from_dst_file,
559 COLO_MESSAGE_CHECKPOINT_READY, &local_err);
560 if (local_err) {
561 goto out;
562 }
563 bioc = qio_channel_buffer_new(COLO_BUFFER_BASE_SIZE);
564 fb = qemu_file_new_output(QIO_CHANNEL(bioc));
565 object_unref(OBJECT(bioc));
566
567 bql_lock();
568 replication_start_all(REPLICATION_MODE_PRIMARY, &local_err);
569 if (local_err) {
570 bql_unlock();
571 goto out;
572 }
573
574 vm_start();
575 bql_unlock();
576 trace_colo_vm_state_change("stop", "run");
577
578 timer_mod(s->colo_delay_timer, qemu_clock_get_ms(QEMU_CLOCK_HOST) +
579 migrate_checkpoint_delay());
580
581 while (s->state == MIGRATION_STATUS_COLO) {
582 if (failover_get_state() != FAILOVER_STATUS_NONE) {
583 error_report("failover request");
584 goto out;
585 }
586
587 qemu_event_wait(&s->colo_checkpoint_event);
588
589 if (s->state != MIGRATION_STATUS_COLO) {
590 goto out;
591 }
592 ret = colo_do_checkpoint_transaction(s, bioc, fb);
593 if (ret < 0) {
594 goto out;
595 }
596 }
597
598 out:
599 /* Throw the unreported error message after exited from loop */
600 if (local_err) {
601 error_report_err(local_err);
602 }
603
604 if (fb) {
605 qemu_fclose(fb);
606 }
607
608 /*
609 * There are only two reasons we can get here, some error happened
610 * or the user triggered failover.
611 */
612 switch (failover_get_state()) {
613 case FAILOVER_STATUS_COMPLETED:
614 qapi_event_send_colo_exit(COLO_MODE_PRIMARY,
615 COLO_EXIT_REASON_REQUEST);
616 break;
617 default:
618 qapi_event_send_colo_exit(COLO_MODE_PRIMARY,
619 COLO_EXIT_REASON_ERROR);
620 }
621
622 /* Hope this not to be too long to wait here */
623 qemu_event_wait(&s->colo_exit_event);
624 qemu_event_destroy(&s->colo_exit_event);
625
626 /*
627 * It is safe to unregister notifier after failover finished.
628 * Besides, colo_delay_timer and colo_checkpoint_sem can't be
629 * released before unregister notifier, or there will be use-after-free
630 * error.
631 */
632 colo_compare_unregister_notifier(&packets_compare_notifier);
633 timer_free(s->colo_delay_timer);
634 qemu_event_destroy(&s->colo_checkpoint_event);
635
636 /*
637 * Must be called after failover BH is completed,
638 * Or the failover BH may shutdown the wrong fd that
639 * re-used by other threads after we release here.
640 */
641 if (s->rp_state.from_dst_file) {
642 qemu_fclose(s->rp_state.from_dst_file);
643 s->rp_state.from_dst_file = NULL;
644 }
645 }
646
migrate_start_colo_process(MigrationState * s)647 void migrate_start_colo_process(MigrationState *s)
648 {
649 bql_unlock();
650 qemu_event_init(&s->colo_checkpoint_event, false);
651 s->colo_delay_timer = timer_new_ms(QEMU_CLOCK_HOST,
652 colo_checkpoint_notify_timer, NULL);
653
654 qemu_event_init(&s->colo_exit_event, false);
655 colo_process_checkpoint(s);
656 bql_lock();
657 }
658
colo_incoming_process_checkpoint(MigrationIncomingState * mis,QEMUFile * fb,QIOChannelBuffer * bioc,Error ** errp)659 static void colo_incoming_process_checkpoint(MigrationIncomingState *mis,
660 QEMUFile *fb, QIOChannelBuffer *bioc, Error **errp)
661 {
662 uint64_t total_size;
663 uint64_t value;
664 Error *local_err = NULL;
665 int ret;
666
667 bql_lock();
668 vm_stop_force_state(RUN_STATE_COLO);
669 bql_unlock();
670 trace_colo_vm_state_change("run", "stop");
671
672 /* FIXME: This is unnecessary for periodic checkpoint mode */
673 colo_send_message(mis->to_src_file, COLO_MESSAGE_CHECKPOINT_REPLY,
674 &local_err);
675 if (local_err) {
676 error_propagate(errp, local_err);
677 return;
678 }
679
680 colo_receive_check_message(mis->from_src_file,
681 COLO_MESSAGE_VMSTATE_SEND, &local_err);
682 if (local_err) {
683 error_propagate(errp, local_err);
684 return;
685 }
686
687 bql_lock();
688 cpu_synchronize_all_states();
689 ret = qemu_loadvm_state_main(mis->from_src_file, mis);
690 bql_unlock();
691
692 if (ret < 0) {
693 error_setg(errp, "Load VM's live state (ram) error");
694 return;
695 }
696
697 value = colo_receive_message_value(mis->from_src_file,
698 COLO_MESSAGE_VMSTATE_SIZE, &local_err);
699 if (local_err) {
700 error_propagate(errp, local_err);
701 return;
702 }
703
704 /*
705 * Read VM device state data into channel buffer,
706 * It's better to re-use the memory allocated.
707 * Here we need to handle the channel buffer directly.
708 */
709 if (value > bioc->capacity) {
710 bioc->capacity = value;
711 bioc->data = g_realloc(bioc->data, bioc->capacity);
712 }
713 total_size = qemu_get_buffer(mis->from_src_file, bioc->data, value);
714 if (total_size != value) {
715 error_setg(errp, "Got %" PRIu64 " VMState data, less than expected"
716 " %" PRIu64, total_size, value);
717 return;
718 }
719 bioc->usage = total_size;
720 qio_channel_io_seek(QIO_CHANNEL(bioc), 0, 0, NULL);
721
722 colo_send_message(mis->to_src_file, COLO_MESSAGE_VMSTATE_RECEIVED,
723 &local_err);
724 if (local_err) {
725 error_propagate(errp, local_err);
726 return;
727 }
728
729 bql_lock();
730 vmstate_loading = true;
731 colo_flush_ram_cache();
732 ret = qemu_load_device_state(fb);
733 if (ret < 0) {
734 error_setg(errp, "COLO: load device state failed");
735 vmstate_loading = false;
736 bql_unlock();
737 return;
738 }
739
740 replication_get_error_all(&local_err);
741 if (local_err) {
742 error_propagate(errp, local_err);
743 vmstate_loading = false;
744 bql_unlock();
745 return;
746 }
747
748 /* discard colo disk buffer */
749 replication_do_checkpoint_all(&local_err);
750 if (local_err) {
751 error_propagate(errp, local_err);
752 vmstate_loading = false;
753 bql_unlock();
754 return;
755 }
756 /* Notify all filters of all NIC to do checkpoint */
757 colo_notify_filters_event(COLO_EVENT_CHECKPOINT, &local_err);
758
759 if (local_err) {
760 error_propagate(errp, local_err);
761 vmstate_loading = false;
762 bql_unlock();
763 return;
764 }
765
766 vmstate_loading = false;
767 vm_start();
768 bql_unlock();
769 trace_colo_vm_state_change("stop", "run");
770
771 if (failover_get_state() == FAILOVER_STATUS_RELAUNCH) {
772 return;
773 }
774
775 colo_send_message(mis->to_src_file, COLO_MESSAGE_VMSTATE_LOADED,
776 &local_err);
777 error_propagate(errp, local_err);
778 }
779
colo_wait_handle_message(MigrationIncomingState * mis,QEMUFile * fb,QIOChannelBuffer * bioc,Error ** errp)780 static void colo_wait_handle_message(MigrationIncomingState *mis,
781 QEMUFile *fb, QIOChannelBuffer *bioc, Error **errp)
782 {
783 COLOMessage msg;
784 Error *local_err = NULL;
785
786 msg = colo_receive_message(mis->from_src_file, &local_err);
787 if (local_err) {
788 error_propagate(errp, local_err);
789 return;
790 }
791
792 switch (msg) {
793 case COLO_MESSAGE_CHECKPOINT_REQUEST:
794 colo_incoming_process_checkpoint(mis, fb, bioc, errp);
795 break;
796 default:
797 error_setg(errp, "Got unknown COLO message: %d", msg);
798 break;
799 }
800 }
801
colo_shutdown(void)802 void colo_shutdown(void)
803 {
804 MigrationIncomingState *mis = NULL;
805 MigrationState *s = NULL;
806
807 switch (get_colo_mode()) {
808 case COLO_MODE_PRIMARY:
809 s = migrate_get_current();
810 qemu_event_set(&s->colo_checkpoint_event);
811 qemu_event_set(&s->colo_exit_event);
812 break;
813 case COLO_MODE_SECONDARY:
814 mis = migration_incoming_get_current();
815 qemu_event_set(&mis->colo_incoming_event);
816 break;
817 default:
818 break;
819 }
820 }
821
colo_process_incoming_thread(void * opaque)822 static void *colo_process_incoming_thread(void *opaque)
823 {
824 MigrationIncomingState *mis = opaque;
825 QEMUFile *fb = NULL;
826 QIOChannelBuffer *bioc = NULL; /* Cache incoming device state */
827 Error *local_err = NULL;
828
829 rcu_register_thread();
830 qemu_event_init(&mis->colo_incoming_event, false);
831
832 migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE,
833 MIGRATION_STATUS_COLO);
834
835 if (get_colo_mode() != COLO_MODE_SECONDARY) {
836 error_report("COLO mode must be COLO_MODE_SECONDARY");
837 return NULL;
838 }
839
840 /* Make sure all file formats throw away their mutable metadata */
841 bql_lock();
842 migration_block_activate(&local_err);
843 bql_unlock();
844 if (local_err) {
845 error_report_err(local_err);
846 return NULL;
847 }
848
849 failover_init_state();
850
851 mis->to_src_file = qemu_file_get_return_path(mis->from_src_file);
852 if (!mis->to_src_file) {
853 error_report("COLO incoming thread: Open QEMUFile to_src_file failed");
854 goto out;
855 }
856 /*
857 * Note: the communication between Primary side and Secondary side
858 * should be sequential, we set the fd to unblocked in migration incoming
859 * coroutine, and here we are in the COLO incoming thread, so it is ok to
860 * set the fd back to blocked.
861 */
862 qemu_file_set_blocking(mis->from_src_file, true);
863
864 colo_incoming_start_dirty_log();
865
866 bioc = qio_channel_buffer_new(COLO_BUFFER_BASE_SIZE);
867 fb = qemu_file_new_input(QIO_CHANNEL(bioc));
868 object_unref(OBJECT(bioc));
869
870 bql_lock();
871 replication_start_all(REPLICATION_MODE_SECONDARY, &local_err);
872 if (local_err) {
873 bql_unlock();
874 goto out;
875 }
876 vm_start();
877 bql_unlock();
878 trace_colo_vm_state_change("stop", "run");
879
880 colo_send_message(mis->to_src_file, COLO_MESSAGE_CHECKPOINT_READY,
881 &local_err);
882 if (local_err) {
883 goto out;
884 }
885
886 while (mis->state == MIGRATION_STATUS_COLO) {
887 colo_wait_handle_message(mis, fb, bioc, &local_err);
888 if (local_err) {
889 error_report_err(local_err);
890 break;
891 }
892
893 if (failover_get_state() == FAILOVER_STATUS_RELAUNCH) {
894 failover_set_state(FAILOVER_STATUS_RELAUNCH,
895 FAILOVER_STATUS_NONE);
896 failover_request_active(NULL);
897 break;
898 }
899
900 if (failover_get_state() != FAILOVER_STATUS_NONE) {
901 error_report("failover request");
902 break;
903 }
904 }
905
906 out:
907 /*
908 * There are only two reasons we can get here, some error happened
909 * or the user triggered failover.
910 */
911 switch (failover_get_state()) {
912 case FAILOVER_STATUS_COMPLETED:
913 qapi_event_send_colo_exit(COLO_MODE_SECONDARY,
914 COLO_EXIT_REASON_REQUEST);
915 break;
916 default:
917 qapi_event_send_colo_exit(COLO_MODE_SECONDARY,
918 COLO_EXIT_REASON_ERROR);
919 }
920
921 if (fb) {
922 qemu_fclose(fb);
923 }
924
925 /* Hope this not to be too long to loop here */
926 qemu_event_wait(&mis->colo_incoming_event);
927 qemu_event_destroy(&mis->colo_incoming_event);
928
929 rcu_unregister_thread();
930 return NULL;
931 }
932
colo_incoming_co(void)933 void coroutine_fn colo_incoming_co(void)
934 {
935 MigrationIncomingState *mis = migration_incoming_get_current();
936 QemuThread th;
937
938 assert(bql_locked());
939 assert(migration_incoming_colo_enabled());
940
941 qemu_thread_create(&th, MIGRATION_THREAD_DST_COLO,
942 colo_process_incoming_thread,
943 mis, QEMU_THREAD_JOINABLE);
944
945 mis->colo_incoming_co = qemu_coroutine_self();
946 qemu_coroutine_yield();
947 mis->colo_incoming_co = NULL;
948
949 bql_unlock();
950 /* Wait checkpoint incoming thread exit before free resource */
951 qemu_thread_join(&th);
952 bql_lock();
953
954 /* We hold the global BQL, so it is safe here */
955 colo_release_ram_cache();
956 }
957