Linux preempt-rt

Check our new training course

Real-Time Linux with PREEMPT_RT

Check our new training course
with Creative Commons CC-BY-SA
lecture and lab materials

Bootlin logo

Elixir Cross Referencer

  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
/*
 * 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/main-loop.h"
#include "migration/migration.h"
#include "monitor/monitor.h"
#include "migration/qemu-file.h"
#include "sysemu/sysemu.h"
#include "block/block.h"
#include "qemu/sockets.h"
#include "migration/block.h"
#include "qemu/thread.h"
#include "qmp-commands.h"
#include "trace.h"

enum {
    MIG_STATE_ERROR = -1,
    MIG_STATE_NONE,
    MIG_STATE_SETUP,
    MIG_STATE_CANCELLING,
    MIG_STATE_CANCELLED,
    MIG_STATE_ACTIVE,
    MIG_STATE_COMPLETED,
};

#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)

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

static NotifierList migration_state_notifiers =
    NOTIFIER_LIST_INITIALIZER(migration_state_notifiers);

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

MigrationState *migrate_get_current(void)
{
    static MigrationState current_migration = {
        .state = MIG_STATE_NONE,
        .bandwidth_limit = MAX_THROTTLE,
        .xbzrle_cache_size = DEFAULT_MIGRATE_CACHE_SIZE,
        .mbps = -1,
    };

    return &current_migration;
}

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

    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;

    ret = qemu_loadvm_state(f);
    qemu_fclose(f);
    free_xbzrle_decoded_buf();
    if (ret < 0) {
        error_report("load of migration failed: %s", strerror(-ret));
        exit(EXIT_FAILURE);
    }
    qemu_announce_self();

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

    if (autostart) {
        vm_start();
    } else {
        runstate_set(RUN_STATE_PAUSED);
    }
}

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

    assert(fd != -1);
    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;
}

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 MIG_STATE_NONE:
        /* no migration has happened ever */
        break;
    case MIG_STATE_SETUP:
        info->has_status = true;
        info->status = g_strdup("setup");
        info->has_total_time = false;
        break;
    case MIG_STATE_ACTIVE:
    case MIG_STATE_CANCELLING:
        info->has_status = true;
        info->status = g_strdup("active");
        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 MIG_STATE_COMPLETED:
        get_xbzrle_cache_stats(info);

        info->has_status = true;
        info->status = g_strdup("completed");
        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 MIG_STATE_ERROR:
        info->has_status = true;
        info->status = g_strdup("failed");
        break;
    case MIG_STATE_CANCELLED:
        info->has_status = true;
        info->status = g_strdup("cancelled");
        break;
    }

    return info;
}

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

    if (s->state == MIG_STATE_ACTIVE || s->state == MIG_STATE_SETUP) {
        error_set(errp, QERR_MIGRATION_ACTIVE);
        return;
    }

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

/* 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) == new_state) {
        trace_migrate_set_state(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();

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

    assert(s->state != MIG_STATE_ACTIVE);

    if (s->state != MIG_STATE_COMPLETED) {
        qemu_savevm_state_cancel();
        if (s->state == MIG_STATE_CANCELLING) {
            migrate_set_state(s, MIG_STATE_CANCELLING, MIG_STATE_CANCELLED);
        }
    }

    notifier_list_notify(&migration_state_notifiers, s);
}

void migrate_fd_error(MigrationState *s)
{
    trace_migrate_fd_error();
    assert(s->file == NULL);
    s->state = MIG_STATE_ERROR;
    trace_migrate_set_state(MIG_STATE_ERROR);
    notifier_list_notify(&migration_state_notifiers, s);
}

static void migrate_fd_cancel(MigrationState *s)
{
    int old_state ;
    trace_migrate_fd_cancel();

    do {
        old_state = s->state;
        if (old_state != MIG_STATE_SETUP && old_state != MIG_STATE_ACTIVE) {
            break;
        }
        migrate_set_state(s, old_state, MIG_STATE_CANCELLING);
    } while (s->state != MIG_STATE_CANCELLING);
}

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 == MIG_STATE_SETUP;
}

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

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

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;

    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->bandwidth_limit = bandwidth_limit;
    s->state = MIG_STATE_SETUP;
    trace_migrate_set_state(MIG_STATE_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(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 == MIG_STATE_ACTIVE || s->state == MIG_STATE_SETUP ||
        s->state == MIG_STATE_CANCELLING) {
        error_set(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;
    }

    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_set(errp, QERR_INVALID_PARAMETER_VALUE, "uri", "a valid migration protocol");
        s->state = MIG_STATE_ERROR;
        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_set(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_set(errp, QERR_INVALID_PARAMETER_VALUE, "cache size",
                  "exceeds guest ram size ");
        return;
    }

    new_size = xbzrle_cache_resize(value);
    if (new_size < 0) {
        error_set(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_rdma_pin_all(void)
{
    MigrationState *s;

    s = migrate_get_current();

    return s->enabled_capabilities[MIGRATION_CAPABILITY_RDMA_PIN_ALL];
}

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];
}

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;
    bool old_vm_running = false;

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

    s->setup_time = qemu_clock_get_ms(QEMU_CLOCK_HOST) - setup_start;
    migrate_set_state(s, MIG_STATE_SETUP, MIG_STATE_ACTIVE);

    while (s->state == MIG_STATE_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 = 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, MIG_STATE_ACTIVE, MIG_STATE_ERROR);
                    break;
                }

                if (!qemu_file_get_error(s->file)) {
                    migrate_set_state(s, MIG_STATE_ACTIVE, MIG_STATE_COMPLETED);
                    break;
                }
            }
        }

        if (qemu_file_get_error(s->file)) {
            migrate_set_state(s, MIG_STATE_ACTIVE, MIG_STATE_ERROR);
            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);
        }
    }

    qemu_mutex_lock_iothread();
    if (s->state == MIG_STATE_COMPLETED) {
        int64_t end_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
        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();

    return NULL;
}

void migrate_fd_connect(MigrationState *s)
{
    s->state = MIG_STATE_SETUP;
    trace_migrate_set_state(MIG_STATE_SETUP);

    /* 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);

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