summaryrefslogtreecommitdiffstats
path: root/qemu/migration/migration.c
blob: 4ddb9adce41ba5f55dbdfde6391c7ed95b071b7e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
/*
 * QEMU live migration
 *
 * Copyright IBM, Corp. 2008
 *
 * Authors:
 *  Anthony Liguori   <aliguori@us.ibm.com>
 *
 * This work is licensed under the terms of the GNU GPL, version 2.  See
 * the COPYING file in the top-level directory.
 *
 * Contributions after 2012-01-13 are licensed under the terms of the
 * GNU GPL, version 2 or (at your option) any later version.
 */

#include "qemu-common.h"
#include "qemu/error-report.h"
#include "qemu/main-loop.h"
#include "migration/migration.h"
#include "migration/qemu-file.h"
#include "sysemu/sysemu.h"
#include "block/block.h"
#include "qapi/qmp/qerror.h"
#include "qemu/sockets.h"
#include "qemu/rcu.h"
#include "migration/block.h"
#include "qemu/thread.h"
#include "qmp-commands.h"
#include "trace.h"
#include "qapi/util.h"
#include "qapi-event.h"

#define MAX_THROTTLE  (32 << 20)      /* Migration speed throttling */

/* Amount of time to allocate to each "chunk" of bandwidth-throttled
 * data. */
#define BUFFER_DELAY     100
#define XFER_LIMIT_RATIO (1000 / BUFFER_DELAY)

/* Default compression thread count */
#define DEFAULT_MIGRATE_COMPRESS_THREAD_COUNT 8
/* Default decompression thread count, usually decompression is at
 * least 4 times as fast as compression.*/
#define DEFAULT_MIGRATE_DECOMPRESS_THREAD_COUNT 2
/*0: means nocompress, 1: best speed, ... 9: best compress ratio */
#define DEFAULT_MIGRATE_COMPRESS_LEVEL 1

/* Migration XBZRLE default cache size */
#define DEFAULT_MIGRATE_CACHE_SIZE (64 * 1024 * 1024)

static NotifierList migration_state_notifiers =
    NOTIFIER_LIST_INITIALIZER(migration_state_notifiers);

static bool deferred_incoming;

/* When we add fault tolerance, we could have several
   migrations at once.  For now we don't need to add
   dynamic creation of migration */

/* For outgoing */
MigrationState *migrate_get_current(void)
{
    static MigrationState current_migration = {
        .state = MIGRATION_STATUS_NONE,
        .bandwidth_limit = MAX_THROTTLE,
        .xbzrle_cache_size = DEFAULT_MIGRATE_CACHE_SIZE,
        .mbps = -1,
        .parameters[MIGRATION_PARAMETER_COMPRESS_LEVEL] =
                DEFAULT_MIGRATE_COMPRESS_LEVEL,
        .parameters[MIGRATION_PARAMETER_COMPRESS_THREADS] =
                DEFAULT_MIGRATE_COMPRESS_THREAD_COUNT,
        .parameters[MIGRATION_PARAMETER_DECOMPRESS_THREADS] =
                DEFAULT_MIGRATE_DECOMPRESS_THREAD_COUNT,
    };

    return &current_migration;
}

/* For incoming */
static MigrationIncomingState *mis_current;

MigrationIncomingState *migration_incoming_get_current(void)
{
    return mis_current;
}

MigrationIncomingState *migration_incoming_state_new(QEMUFile* f)
{
    mis_current = g_malloc0(sizeof(MigrationIncomingState));
    mis_current->file = f;
    QLIST_INIT(&mis_current->loadvm_handlers);

    return mis_current;
}

void migration_incoming_state_destroy(void)
{
    loadvm_free_handlers(mis_current);
    g_free(mis_current);
    mis_current = NULL;
}


typedef struct {
    bool optional;
    uint32_t size;
    uint8_t runstate[100];
    RunState state;
    bool received;
} GlobalState;

static GlobalState global_state;

int global_state_store(void)
{
    if (!runstate_store((char *)global_state.runstate,
                        sizeof(global_state.runstate))) {
        error_report("runstate name too big: %s", global_state.runstate);
        trace_migrate_state_too_big();
        return -EINVAL;
    }
    return 0;
}

void global_state_store_running(void)
{
    const char *state = RunState_lookup[RUN_STATE_RUNNING];
    strncpy((char *)global_state.runstate,
           state, sizeof(global_state.runstate));
}

static bool global_state_received(void)
{
    return global_state.received;
}

static RunState global_state_get_runstate(void)
{
    return global_state.state;
}

void global_state_set_optional(void)
{
    global_state.optional = true;
}

static bool global_state_needed(void *opaque)
{
    GlobalState *s = opaque;
    char *runstate = (char *)s->runstate;

    /* If it is not optional, it is mandatory */

    if (s->optional == false) {
        return true;
    }

    /* If state is running or paused, it is not needed */

    if (strcmp(runstate, "running") == 0 ||
        strcmp(runstate, "paused") == 0) {
        return false;
    }

    /* for any other state it is needed */
    return true;
}

static int global_state_post_load(void *opaque, int version_id)
{
    GlobalState *s = opaque;
    Error *local_err = NULL;
    int r;
    char *runstate = (char *)s->runstate;

    s->received = true;
    trace_migrate_global_state_post_load(runstate);

    r = qapi_enum_parse(RunState_lookup, runstate, RUN_STATE_MAX,
                                -1, &local_err);

    if (r == -1) {
        if (local_err) {
            error_report_err(local_err);
        }
        return -EINVAL;
    }
    s->state = r;

    return 0;
}

static void global_state_pre_save(void *opaque)
{
    GlobalState *s = opaque;

    trace_migrate_global_state_pre_save((char *)s->runstate);
    s->size = strlen((char *)s->runstate) + 1;
}

static const VMStateDescription vmstate_globalstate = {
    .name = "globalstate",
    .version_id = 1,
    .minimum_version_id = 1,
    .post_load = global_state_post_load,
    .pre_save = global_state_pre_save,
    .needed = global_state_needed,
    .fields = (VMStateField[]) {
        VMSTATE_UINT32(size, GlobalState),
        VMSTATE_BUFFER(runstate, GlobalState),
        VMSTATE_END_OF_LIST()
    },
};

void register_global_state(void)
{
    /* We would use it independently that we receive it */
    strcpy((char *)&global_state.runstate, "");
    global_state.received = false;
    vmstate_register(NULL, 0, &vmstate_globalstate, &global_state);
}

static void migrate_generate_event(int new_state)
{
    if (migrate_use_events()) {
        qapi_event_send_migration(new_state, &error_abort);
    }
}

/*
 * Called on -incoming with a defer: uri.
 * The migration can be started later after any parameters have been
 * changed.
 */
static void deferred_incoming_migration(Error **errp)
{
    if (deferred_incoming) {
        error_setg(errp, "Incoming migration already deferred");
    }
    deferred_incoming = true;
}

void qemu_start_incoming_migration(const char *uri, Error **errp)
{
    const char *p;

    qapi_event_send_migration(MIGRATION_STATUS_SETUP, &error_abort);
    if (!strcmp(uri, "defer")) {
        deferred_incoming_migration(errp);
    } else if (strstart(uri, "tcp:", &p)) {
        tcp_start_incoming_migration(p, errp);
#ifdef CONFIG_RDMA
    } else if (strstart(uri, "rdma:", &p)) {
        rdma_start_incoming_migration(p, errp);
#endif
#if !defined(WIN32)
    } else if (strstart(uri, "exec:", &p)) {
        exec_start_incoming_migration(p, errp);
    } else if (strstart(uri, "unix:", &p)) {
        unix_start_incoming_migration(p, errp);
    } else if (strstart(uri, "fd:", &p)) {
        fd_start_incoming_migration(p, errp);
#endif
    } else {
        error_setg(errp, "unknown migration protocol: %s", uri);
    }
}

static void process_incoming_migration_co(void *opaque)
{
    QEMUFile *f = opaque;
    Error *local_err = NULL;
    int ret;

    migration_incoming_state_new(f);
    migrate_generate_event(MIGRATION_STATUS_ACTIVE);
    ret = qemu_loadvm_state(f);

    qemu_fclose(f);
    free_xbzrle_decoded_buf();
    migration_incoming_state_destroy();

    if (ret < 0) {
        migrate_generate_event(MIGRATION_STATUS_FAILED);
        error_report("load of migration failed: %s", strerror(-ret));
        migrate_decompress_threads_join();
        exit(EXIT_FAILURE);
    }
    migrate_generate_event(MIGRATION_STATUS_COMPLETED);
    qemu_announce_self();

    /* Make sure all file formats flush their mutable metadata */
    bdrv_invalidate_cache_all(&local_err);
    if (local_err) {
        error_report_err(local_err);
        migrate_decompress_threads_join();
        exit(EXIT_FAILURE);
    }

    /* If global state section was not received or we are in running
       state, we need to obey autostart. Any other state is set with
       runstate_set. */

    if (!global_state_received() ||
        global_state_get_runstate() == RUN_STATE_RUNNING) {
        if (autostart) {
            vm_start();
        } else {
            runstate_set(RUN_STATE_PAUSED);
        }
    } else {
        runstate_set(global_state_get_runstate());
    }
    migrate_decompress_threads_join();
}

void process_incoming_migration(QEMUFile *f)
{
    Coroutine *co = qemu_coroutine_create(process_incoming_migration_co);
    int fd = qemu_get_fd(f);

    assert(fd != -1);
    migrate_decompress_threads_create();
    qemu_set_nonblock(fd);
    qemu_coroutine_enter(co, f);
}

/* amount of nanoseconds we are willing to wait for migration to be down.
 * the choice of nanoseconds is because it is the maximum resolution that
 * get_clock() can achieve. It is an internal measure. All user-visible
 * units must be in seconds */
static uint64_t max_downtime = 300000000;

uint64_t migrate_max_downtime(void)
{
    return max_downtime;
}

MigrationCapabilityStatusList *qmp_query_migrate_capabilities(Error **errp)
{
    MigrationCapabilityStatusList *head = NULL;
    MigrationCapabilityStatusList *caps;
    MigrationState *s = migrate_get_current();
    int i;

    caps = NULL; /* silence compiler warning */
    for (i = 0; i < MIGRATION_CAPABILITY_MAX; i++) {
        if (head == NULL) {
            head = g_malloc0(sizeof(*caps));
            caps = head;
        } else {
            caps->next = g_malloc0(sizeof(*caps));
            caps = caps->next;
        }
        caps->value =
            g_malloc(sizeof(*caps->value));
        caps->value->capability = i;
        caps->value->state = s->enabled_capabilities[i];
    }

    return head;
}

MigrationParameters *qmp_query_migrate_parameters(Error **errp)
{
    MigrationParameters *params;
    MigrationState *s = migrate_get_current();

    params = g_malloc0(sizeof(*params));
    params->compress_level = s->parameters[MIGRATION_PARAMETER_COMPRESS_LEVEL];
    params->compress_threads =
            s->parameters[MIGRATION_PARAMETER_COMPRESS_THREADS];
    params->decompress_threads =
            s->parameters[MIGRATION_PARAMETER_DECOMPRESS_THREADS];

    return params;
}

static void get_xbzrle_cache_stats(MigrationInfo *info)
{
    if (migrate_use_xbzrle()) {
        info->has_xbzrle_cache = true;
        info->xbzrle_cache = g_malloc0(sizeof(*info->xbzrle_cache));
        info->xbzrle_cache->cache_size = migrate_xbzrle_cache_size();
        info->xbzrle_cache->bytes = xbzrle_mig_bytes_transferred();
        info->xbzrle_cache->pages = xbzrle_mig_pages_transferred();
        info->xbzrle_cache->cache_miss = xbzrle_mig_pages_cache_miss();
        info->xbzrle_cache->cache_miss_rate = xbzrle_mig_cache_miss_rate();
        info->xbzrle_cache->overflow = xbzrle_mig_pages_overflow();
    }
}

MigrationInfo *qmp_query_migrate(Error **errp)
{
    MigrationInfo *info = g_malloc0(sizeof(*info));
    MigrationState *s = migrate_get_current();

    switch (s->state) {
    case MIGRATION_STATUS_NONE:
        /* no migration has happened ever */
        break;
    case MIGRATION_STATUS_SETUP:
        info->has_status = true;
        info->has_total_time = false;
        break;
    case MIGRATION_STATUS_ACTIVE:
    case MIGRATION_STATUS_CANCELLING:
        info->has_status = true;
        info->has_total_time = true;
        info->total_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME)
            - s->total_time;
        info->has_expected_downtime = true;
        info->expected_downtime = s->expected_downtime;
        info->has_setup_time = true;
        info->setup_time = s->setup_time;

        info->has_ram = true;
        info->ram = g_malloc0(sizeof(*info->ram));
        info->ram->transferred = ram_bytes_transferred();
        info->ram->remaining = ram_bytes_remaining();
        info->ram->total = ram_bytes_total();
        info->ram->duplicate = dup_mig_pages_transferred();
        info->ram->skipped = skipped_mig_pages_transferred();
        info->ram->normal = norm_mig_pages_transferred();
        info->ram->normal_bytes = norm_mig_bytes_transferred();
        info->ram->dirty_pages_rate = s->dirty_pages_rate;
        info->ram->mbps = s->mbps;
        info->ram->dirty_sync_count = s->dirty_sync_count;

        if (blk_mig_active()) {
            info->has_disk = true;
            info->disk = g_malloc0(sizeof(*info->disk));
            info->disk->transferred = blk_mig_bytes_transferred();
            info->disk->remaining = blk_mig_bytes_remaining();
            info->disk->total = blk_mig_bytes_total();
        }

        get_xbzrle_cache_stats(info);
        break;
    case MIGRATION_STATUS_COMPLETED:
        get_xbzrle_cache_stats(info);

        info->has_status = true;
        info->has_total_time = true;
        info->total_time = s->total_time;
        info->has_downtime = true;
        info->downtime = s->downtime;
        info->has_setup_time = true;
        info->setup_time = s->setup_time;

        info->has_ram = true;
        info->ram = g_malloc0(sizeof(*info->ram));
        info->ram->transferred = ram_bytes_transferred();
        info->ram->remaining = 0;
        info->ram->total = ram_bytes_total();
        info->ram->duplicate = dup_mig_pages_transferred();
        info->ram->skipped = skipped_mig_pages_transferred();
        info->ram->normal = norm_mig_pages_transferred();
        info->ram->normal_bytes = norm_mig_bytes_transferred();
        info->ram->mbps = s->mbps;
        info->ram->dirty_sync_count = s->dirty_sync_count;
        break;
    case MIGRATION_STATUS_FAILED:
        info->has_status = true;
        break;
    case MIGRATION_STATUS_CANCELLED:
        info->has_status = true;
        break;
    }
    info->status = s->state;

    return info;
}

void qmp_migrate_set_capabilities(MigrationCapabilityStatusList *params,
                                  Error **errp)
{
    MigrationState *s = migrate_get_current();
    MigrationCapabilityStatusList *cap;

    if (s->state == MIGRATION_STATUS_ACTIVE ||
        s->state == MIGRATION_STATUS_SETUP) {
        error_setg(errp, QERR_MIGRATION_ACTIVE);
        return;
    }

    for (cap = params; cap; cap = cap->next) {
        s->enabled_capabilities[cap->value->capability] = cap->value->state;
    }
}

void qmp_migrate_set_parameters(bool has_compress_level,
                                int64_t compress_level,
                                bool has_compress_threads,
                                int64_t compress_threads,
                                bool has_decompress_threads,
                                int64_t decompress_threads, Error **errp)
{
    MigrationState *s = migrate_get_current();

    if (has_compress_level && (compress_level < 0 || compress_level > 9)) {
        error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "compress_level",
                   "is invalid, it should be in the range of 0 to 9");
        return;
    }
    if (has_compress_threads &&
            (compress_threads < 1 || compress_threads > 255)) {
        error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
                   "compress_threads",
                   "is invalid, it should be in the range of 1 to 255");
        return;
    }
    if (has_decompress_threads &&
            (decompress_threads < 1 || decompress_threads > 255)) {
        error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
                   "decompress_threads",
                   "is invalid, it should be in the range of 1 to 255");
        return;
    }

    if (has_compress_level) {
        s->parameters[MIGRATION_PARAMETER_COMPRESS_LEVEL] = compress_level;
    }
    if (has_compress_threads) {
        s->parameters[MIGRATION_PARAMETER_COMPRESS_THREADS] = compress_threads;
    }
    if (has_decompress_threads) {
        s->parameters[MIGRATION_PARAMETER_DECOMPRESS_THREADS] =
                                                    decompress_threads;
    }
}

/* shared migration helpers */

static void migrate_set_state(MigrationState *s, int old_state, int new_state)
{
    if (atomic_cmpxchg(&s->state, old_state, new_state) == old_state) {
        trace_migrate_set_state(new_state);
        migrate_generate_event(new_state);
    }
}

static void migrate_fd_cleanup(void *opaque)
{
    MigrationState *s = opaque;

    qemu_bh_delete(s->cleanup_bh);
    s->cleanup_bh = NULL;

    if (s->file) {
        trace_migrate_fd_cleanup();
        qemu_mutex_unlock_iothread();
        qemu_thread_join(&s->thread);
        qemu_mutex_lock_iothread();

        migrate_compress_threads_join();
        qemu_fclose(s->file);
        s->file = NULL;
    }

    assert(s->state != MIGRATION_STATUS_ACTIVE);

    if (s->state == MIGRATION_STATUS_CANCELLING) {
        migrate_set_state(s, MIGRATION_STATUS_CANCELLING,
                          MIGRATION_STATUS_CANCELLED);
    }

    notifier_list_notify(&migration_state_notifiers, s);
}

void migrate_fd_error(MigrationState *s)
{
    trace_migrate_fd_error();
    assert(s->file == NULL);
    migrate_set_state(s, MIGRATION_STATUS_SETUP, MIGRATION_STATUS_FAILED);
    notifier_list_notify(&migration_state_notifiers, s);
}

static void migrate_fd_cancel(MigrationState *s)
{
    int old_state ;
    QEMUFile *f = migrate_get_current()->file;
    trace_migrate_fd_cancel();

    do {
        old_state = s->state;
        if (old_state != MIGRATION_STATUS_SETUP &&
            old_state != MIGRATION_STATUS_ACTIVE) {
            break;
        }
        migrate_set_state(s, old_state, MIGRATION_STATUS_CANCELLING);
    } while (s->state != MIGRATION_STATUS_CANCELLING);

    /*
     * If we're unlucky the migration code might be stuck somewhere in a
     * send/write while the network has failed and is waiting to timeout;
     * if we've got shutdown(2) available then we can force it to quit.
     * The outgoing qemu file gets closed in migrate_fd_cleanup that is
     * called in a bh, so there is no race against this cancel.
     */
    if (s->state == MIGRATION_STATUS_CANCELLING && f) {
        qemu_file_shutdown(f);
    }
}

void add_migration_state_change_notifier(Notifier *notify)
{
    notifier_list_add(&migration_state_notifiers, notify);
}

void remove_migration_state_change_notifier(Notifier *notify)
{
    notifier_remove(notify);
}

bool migration_in_setup(MigrationState *s)
{
    return s->state == MIGRATION_STATUS_SETUP;
}

bool migration_has_finished(MigrationState *s)
{
    return s->state == MIGRATION_STATUS_COMPLETED;
}

bool migration_has_failed(MigrationState *s)
{
    return (s->state == MIGRATION_STATUS_CANCELLED ||
            s->state == MIGRATION_STATUS_FAILED);
}

static MigrationState *migrate_init(const MigrationParams *params)
{
    MigrationState *s = migrate_get_current();
    int64_t bandwidth_limit = s->bandwidth_limit;
    bool enabled_capabilities[MIGRATION_CAPABILITY_MAX];
    int64_t xbzrle_cache_size = s->xbzrle_cache_size;
    int compress_level = s->parameters[MIGRATION_PARAMETER_COMPRESS_LEVEL];
    int compress_thread_count =
            s->parameters[MIGRATION_PARAMETER_COMPRESS_THREADS];
    int decompress_thread_count =
            s->parameters[MIGRATION_PARAMETER_DECOMPRESS_THREADS];

    memcpy(enabled_capabilities, s->enabled_capabilities,
           sizeof(enabled_capabilities));

    memset(s, 0, sizeof(*s));
    s->params = *params;
    memcpy(s->enabled_capabilities, enabled_capabilities,
           sizeof(enabled_capabilities));
    s->xbzrle_cache_size = xbzrle_cache_size;

    s->parameters[MIGRATION_PARAMETER_COMPRESS_LEVEL] = compress_level;
    s->parameters[MIGRATION_PARAMETER_COMPRESS_THREADS] =
               compress_thread_count;
    s->parameters[MIGRATION_PARAMETER_DECOMPRESS_THREADS] =
               decompress_thread_count;
    s->bandwidth_limit = bandwidth_limit;
    migrate_set_state(s, MIGRATION_STATUS_NONE, MIGRATION_STATUS_SETUP);

    s->total_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
    return s;
}

static GSList *migration_blockers;

void migrate_add_blocker(Error *reason)
{
    migration_blockers = g_slist_prepend(migration_blockers, reason);
}

void migrate_del_blocker(Error *reason)
{
    migration_blockers = g_slist_remove(migration_blockers, reason);
}

void qmp_migrate_incoming(const char *uri, Error **errp)
{
    Error *local_err = NULL;
    static bool once = true;

    if (!deferred_incoming) {
        error_setg(errp, "For use with '-incoming defer'");
        return;
    }
    if (!once) {
        error_setg(errp, "The incoming migration has already been started");
    }

    qemu_start_incoming_migration(uri, &local_err);

    if (local_err) {
        error_propagate(errp, local_err);
        return;
    }

    once = false;
}

void qmp_migrate(const char *uri, bool has_blk, bool blk,
                 bool has_inc, bool inc, bool has_detach, bool detach,
                 Error **errp)
{
    Error *local_err = NULL;
    MigrationState *s = migrate_get_current();
    MigrationParams params;
    const char *p;

    params.blk = has_blk && blk;
    params.shared = has_inc && inc;

    if (s->state == MIGRATION_STATUS_ACTIVE ||
        s->state == MIGRATION_STATUS_SETUP ||
        s->state == MIGRATION_STATUS_CANCELLING) {
        error_setg(errp, QERR_MIGRATION_ACTIVE);
        return;
    }
    if (runstate_check(RUN_STATE_INMIGRATE)) {
        error_setg(errp, "Guest is waiting for an incoming migration");
        return;
    }

    if (qemu_savevm_state_blocked(errp)) {
        return;
    }

    if (migration_blockers) {
        *errp = error_copy(migration_blockers->data);
        return;
    }

    /* We are starting a new migration, so we want to start in a clean
       state.  This change is only needed if previous migration
       failed/was cancelled.  We don't use migrate_set_state() because
       we are setting the initial state, not changing it. */
    s->state = MIGRATION_STATUS_NONE;

    s = migrate_init(&params);

    if (strstart(uri, "tcp:", &p)) {
        tcp_start_outgoing_migration(s, p, &local_err);
#ifdef CONFIG_RDMA
    } else if (strstart(uri, "rdma:", &p)) {
        rdma_start_outgoing_migration(s, p, &local_err);
#endif
#if !defined(WIN32)
    } else if (strstart(uri, "exec:", &p)) {
        exec_start_outgoing_migration(s, p, &local_err);
    } else if (strstart(uri, "unix:", &p)) {
        unix_start_outgoing_migration(s, p, &local_err);
    } else if (strstart(uri, "fd:", &p)) {
        fd_start_outgoing_migration(s, p, &local_err);
#endif
    } else {
        error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "uri",
                   "a valid migration protocol");
        migrate_set_state(s, MIGRATION_STATUS_SETUP, MIGRATION_STATUS_FAILED);
        return;
    }

    if (local_err) {
        migrate_fd_error(s);
        error_propagate(errp, local_err);
        return;
    }
}

void qmp_migrate_cancel(Error **errp)
{
    migrate_fd_cancel(migrate_get_current());
}

void qmp_migrate_set_cache_size(int64_t value, Error **errp)
{
    MigrationState *s = migrate_get_current();
    int64_t new_size;

    /* Check for truncation */
    if (value != (size_t)value) {
        error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cache size",
                   "exceeding address space");
        return;
    }

    /* Cache should not be larger than guest ram size */
    if (value > ram_bytes_total()) {
        error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cache size",
                   "exceeds guest ram size ");
        return;
    }

    new_size = xbzrle_cache_resize(value);
    if (new_size < 0) {
        error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cache size",
                   "is smaller than page size");
        return;
    }

    s->xbzrle_cache_size = new_size;
}

int64_t qmp_query_migrate_cache_size(Error **errp)
{
    return migrate_xbzrle_cache_size();
}

void qmp_migrate_set_speed(int64_t value, Error **errp)
{
    MigrationState *s;

    if (value < 0) {
        value = 0;
    }
    if (value > SIZE_MAX) {
        value = SIZE_MAX;
    }

    s = migrate_get_current();
    s->bandwidth_limit = value;
    if (s->file) {
        qemu_file_set_rate_limit(s->file, s->bandwidth_limit / XFER_LIMIT_RATIO);
    }
}

void qmp_migrate_set_downtime(double value, Error **errp)
{
    value *= 1e9;
    value = MAX(0, MIN(UINT64_MAX, value));
    max_downtime = (uint64_t)value;
}

bool migrate_auto_converge(void)
{
    MigrationState *s;

    s = migrate_get_current();

    return s->enabled_capabilities[MIGRATION_CAPABILITY_AUTO_CONVERGE];
}

bool migrate_zero_blocks(void)
{
    MigrationState *s;

    s = migrate_get_current();

    return s->enabled_capabilities[MIGRATION_CAPABILITY_ZERO_BLOCKS];
}

bool migrate_use_compression(void)
{
    MigrationState *s;

    s = migrate_get_current();

    return s->enabled_capabilities[MIGRATION_CAPABILITY_COMPRESS];
}

int migrate_compress_level(void)
{
    MigrationState *s;

    s = migrate_get_current();

    return s->parameters[MIGRATION_PARAMETER_COMPRESS_LEVEL];
}

int migrate_compress_threads(void)
{
    MigrationState *s;

    s = migrate_get_current();

    return s->parameters[MIGRATION_PARAMETER_COMPRESS_THREADS];
}

int migrate_decompress_threads(void)
{
    MigrationState *s;

    s = migrate_get_current();

    return s->parameters[MIGRATION_PARAMETER_DECOMPRESS_THREADS];
}

bool migrate_use_events(void)
{
    MigrationState *s;

    s = migrate_get_current();

    return s->enabled_capabilities[MIGRATION_CAPABILITY_EVENTS];
}

int migrate_use_xbzrle(void)
{
    MigrationState *s;

    s = migrate_get_current();

    return s->enabled_capabilities[MIGRATION_CAPABILITY_XBZRLE];
}

int64_t migrate_xbzrle_cache_size(void)
{
    MigrationState *s;

    s = migrate_get_current();

    return s->xbzrle_cache_size;
}

/* migration thread support */

static void *migration_thread(void *opaque)
{
    MigrationState *s = opaque;
    int64_t initial_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
    int64_t setup_start = qemu_clock_get_ms(QEMU_CLOCK_HOST);
    int64_t initial_bytes = 0;
    int64_t max_size = 0;
    int64_t start_time = initial_time;
    int64_t end_time;
    bool old_vm_running = false;

    rcu_register_thread();

    qemu_savevm_state_header(s->file);
    qemu_savevm_state_begin(s->file, &s->params);

    s->setup_time = qemu_clock_get_ms(QEMU_CLOCK_HOST) - setup_start;
    migrate_set_state(s, MIGRATION_STATUS_SETUP, MIGRATION_STATUS_ACTIVE);

    while (s->state == MIGRATION_STATUS_ACTIVE) {
        int64_t current_time;
        uint64_t pending_size;

        if (!qemu_file_rate_limit(s->file)) {
            pending_size = qemu_savevm_state_pending(s->file, max_size);
            trace_migrate_pending(pending_size, max_size);
            if (pending_size && pending_size >= max_size) {
                qemu_savevm_state_iterate(s->file);
            } else {
                int ret;

                qemu_mutex_lock_iothread();
                start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
                qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER);
                old_vm_running = runstate_is_running();

                ret = global_state_store();
                if (!ret) {
                    ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
                    if (ret >= 0) {
                        qemu_file_set_rate_limit(s->file, INT64_MAX);
                        qemu_savevm_state_complete(s->file);
                    }
                }
                qemu_mutex_unlock_iothread();

                if (ret < 0) {
                    migrate_set_state(s, MIGRATION_STATUS_ACTIVE,
                                      MIGRATION_STATUS_FAILED);
                    break;
                }

                if (!qemu_file_get_error(s->file)) {
                    migrate_set_state(s, MIGRATION_STATUS_ACTIVE,
                                      MIGRATION_STATUS_COMPLETED);
                    break;
                }
            }
        }

        if (qemu_file_get_error(s->file)) {
            migrate_set_state(s, MIGRATION_STATUS_ACTIVE,
                              MIGRATION_STATUS_FAILED);
            break;
        }
        current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
        if (current_time >= initial_time + BUFFER_DELAY) {
            uint64_t transferred_bytes = qemu_ftell(s->file) - initial_bytes;
            uint64_t time_spent = current_time - initial_time;
            double bandwidth = transferred_bytes / time_spent;
            max_size = bandwidth * migrate_max_downtime() / 1000000;

            s->mbps = time_spent ? (((double) transferred_bytes * 8.0) /
                    ((double) time_spent / 1000.0)) / 1000.0 / 1000.0 : -1;

            trace_migrate_transferred(transferred_bytes, time_spent,
                                      bandwidth, max_size);
            /* if we haven't sent anything, we don't want to recalculate
               10000 is a small enough number for our purposes */
            if (s->dirty_bytes_rate && transferred_bytes > 10000) {
                s->expected_downtime = s->dirty_bytes_rate / bandwidth;
            }

            qemu_file_reset_rate_limit(s->file);
            initial_time = current_time;
            initial_bytes = qemu_ftell(s->file);
        }
        if (qemu_file_rate_limit(s->file)) {
            /* usleep expects microseconds */
            g_usleep((initial_time + BUFFER_DELAY - current_time)*1000);
        }
    }

    end_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);

    qemu_mutex_lock_iothread();
    qemu_savevm_state_cancel();
    if (s->state == MIGRATION_STATUS_COMPLETED) {
        uint64_t transferred_bytes = qemu_ftell(s->file);
        s->total_time = end_time - s->total_time;
        s->downtime = end_time - start_time;
        if (s->total_time) {
            s->mbps = (((double) transferred_bytes * 8.0) /
                       ((double) s->total_time)) / 1000;
        }
        runstate_set(RUN_STATE_POSTMIGRATE);
    } else {
        if (old_vm_running) {
            vm_start();
        }
    }
    qemu_bh_schedule(s->cleanup_bh);
    qemu_mutex_unlock_iothread();

    rcu_unregister_thread();
    return NULL;
}

void migrate_fd_connect(MigrationState *s)
{
    /* This is a best 1st approximation. ns to ms */
    s->expected_downtime = max_downtime/1000000;
    s->cleanup_bh = qemu_bh_new(migrate_fd_cleanup, s);

    qemu_file_set_rate_limit(s->file,
                             s->bandwidth_limit / XFER_LIMIT_RATIO);

    /* Notify before starting migration thread */
    notifier_list_notify(&migration_state_notifiers, s);

    migrate_compress_threads_create();
    qemu_thread_create(&s->thread, "migration", migration_thread, s,
                       QEMU_THREAD_JOINABLE);
}