migration.c

   1 /*
   2  * QEMU live migration
   3  *
   4  * Copyright IBM, Corp. 2008
   5  *
   6  * Authors:
   7  *  Anthony Liguori   <aliguori@us.ibm.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2.  See
  10  * the COPYING file in the top-level directory.
  11  *
  12  * Contributions after 2012-01-13 are licensed under the terms of the
  13  * GNU GPL, version 2 or (at your option) any later version.
  14  */
  15
  16 #include "qemu-common.h"
  17 #include "qemu/main-loop.h"
  18 #include "migration/migration.h"
  19 #include "monitor/monitor.h"
  20 #include "migration/qemu-file.h"
  21 #include "sysemu/sysemu.h"
  22 #include "block/block.h"
  23 #include "qemu/sockets.h"
  24 #include "migration/block.h"
  25 #include "qemu/thread.h"
  26 #include "qmp-commands.h"
  27 #include "trace.h"
  28
  29 enum {
  30     MIG_STATE_ERROR = -1,
  31     MIG_STATE_NONE,
  32     MIG_STATE_SETUP,
  33     MIG_STATE_CANCELLING,
  34     MIG_STATE_CANCELLED,
  35     MIG_STATE_ACTIVE,
  36     MIG_STATE_COMPLETED,
  37 };
  38
  39 #define MAX_THROTTLE  (32 << 20)      /* Migration speed throttling */
  40
  41 /* Amount of time to allocate to each "chunk" of bandwidth-throttled
  42  * data. */
  43 #define BUFFER_DELAY     100
  44 #define XFER_LIMIT_RATIO (1000 / BUFFER_DELAY)
  45
  46 /* Migration XBZRLE default cache size */
  47 #define DEFAULT_MIGRATE_CACHE_SIZE (64 * 1024 * 1024)
  48
  49 static NotifierList migration_state_notifiers =
  50     NOTIFIER_LIST_INITIALIZER(migration_state_notifiers);
  51
  52 /* When we add fault tolerance, we could have several
  53    migrations at once.  For now we don't need to add
  54    dynamic creation of migration */
  55
  56 MigrationState *migrate_get_current(void)
  57 {
  58     static MigrationState current_migration = {
  59         .state = MIG_STATE_NONE,
  60         .bandwidth_limit = MAX_THROTTLE,
  61         .xbzrle_cache_size = DEFAULT_MIGRATE_CACHE_SIZE,
  62         .mbps = -1,
  63     };
  64
  65     return &current_migration;
  66 }
  67
  68 void qemu_start_incoming_migration(const char *uri, Error **errp)
  69 {
  70     const char *p;
  71
  72     if (strstart(uri, "tcp:", &p))
  73         tcp_start_incoming_migration(p, errp);
  74 #ifdef CONFIG_RDMA
  75     else if (strstart(uri, "rdma:", &p))
  76         rdma_start_incoming_migration(p, errp);
  77 #endif
  78 #if !defined(WIN32)
  79     else if (strstart(uri, "exec:", &p))
  80         exec_start_incoming_migration(p, errp);
  81     else if (strstart(uri, "unix:", &p))
  82         unix_start_incoming_migration(p, errp);
  83     else if (strstart(uri, "fd:", &p))
  84         fd_start_incoming_migration(p, errp);
  85 #endif
  86     else {
  87         error_setg(errp, "unknown migration protocol: %s", uri);
  88     }
  89 }
  90
  91 static void process_incoming_migration_co(void *opaque)
  92 {
  93     QEMUFile *f = opaque;
  94     Error *local_err = NULL;
  95     int ret;
  96
  97     ret = qemu_loadvm_state(f);
  98     qemu_fclose(f);
  99     free_xbzrle_decoded_buf();
 100     if (ret < 0) {
 101         fprintf(stderr, "load of migration failed\n");
 102         exit(EXIT_FAILURE);
 103     }
 104     qemu_announce_self();
 105
 106     bdrv_clear_incoming_migration_all();
 107     /* Make sure all file formats flush their mutable metadata */
 108     bdrv_invalidate_cache_all(&local_err);
 109     if (local_err) {
 110         qerror_report_err(local_err);
 111         error_free(local_err);
 112         exit(EXIT_FAILURE);
 113     }
 114
 115     if (autostart) {
 116         vm_start();
 117     } else {
 118         runstate_set(RUN_STATE_PAUSED);
 119     }
 120 }
 121
 122 void process_incoming_migration(QEMUFile *f)
 123 {
 124     Coroutine *co = qemu_coroutine_create(process_incoming_migration_co);
 125     int fd = qemu_get_fd(f);
 126
 127     assert(fd != -1);
 128     qemu_set_nonblock(fd);
 129     qemu_coroutine_enter(co, f);
 130 }
 131
 132 /* amount of nanoseconds we are willing to wait for migration to be down.
 133  * the choice of nanoseconds is because it is the maximum resolution that
 134  * get_clock() can achieve. It is an internal measure. All user-visible
 135  * units must be in seconds */
 136 static uint64_t max_downtime = 30000000;
 137
 138 uint64_t migrate_max_downtime(void)
 139 {
 140     return max_downtime;
 141 }
 142
 143 MigrationCapabilityStatusList *qmp_query_migrate_capabilities(Error **errp)
 144 {
 145     MigrationCapabilityStatusList *head = NULL;
 146     MigrationCapabilityStatusList *caps;
 147     MigrationState *s = migrate_get_current();
 148     int i;
 149
 150     caps = NULL; /* silence compiler warning */
 151     for (i = 0; i < MIGRATION_CAPABILITY_MAX; i++) {
 152         if (head == NULL) {
 153             head = g_malloc0(sizeof(*caps));
 154             caps = head;
 155         } else {
 156             caps->next = g_malloc0(sizeof(*caps));
 157             caps = caps->next;
 158         }
 159         caps->value =
 160             g_malloc(sizeof(*caps->value));
 161         caps->value->capability = i;
 162         caps->value->state = s->enabled_capabilities[i];
 163     }
 164
 165     return head;
 166 }
 167
 168 static void get_xbzrle_cache_stats(MigrationInfo *info)
 169 {
 170     if (migrate_use_xbzrle()) {
 171         info->has_xbzrle_cache = true;
 172         info->xbzrle_cache = g_malloc0(sizeof(*info->xbzrle_cache));
 173         info->xbzrle_cache->cache_size = migrate_xbzrle_cache_size();
 174         info->xbzrle_cache->bytes = xbzrle_mig_bytes_transferred();
 175         info->xbzrle_cache->pages = xbzrle_mig_pages_transferred();
 176         info->xbzrle_cache->cache_miss = xbzrle_mig_pages_cache_miss();
 177         info->xbzrle_cache->overflow = xbzrle_mig_pages_overflow();
 178     }
 179 }
 180
 181 MigrationInfo *qmp_query_migrate(Error **errp)
 182 {
 183     MigrationInfo *info = g_malloc0(sizeof(*info));
 184     MigrationState *s = migrate_get_current();
 185
 186     switch (s->state) {
 187     case MIG_STATE_NONE:
 188         /* no migration has happened ever */
 189         break;
 190     case MIG_STATE_SETUP:
 191         info->has_status = true;
 192         info->status = g_strdup("setup");
 193         info->has_total_time = false;
 194         break;
 195     case MIG_STATE_ACTIVE:
 196     case MIG_STATE_CANCELLING:
 197         info->has_status = true;
 198         info->status = g_strdup("active");
 199         info->has_total_time = true;
 200         info->total_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME)
 201             - s->total_time;
 202         info->has_expected_downtime = true;
 203         info->expected_downtime = s->expected_downtime;
 204         info->has_setup_time = true;
 205         info->setup_time = s->setup_time;
 206
 207         info->has_ram = true;
 208         info->ram = g_malloc0(sizeof(*info->ram));
 209         info->ram->transferred = ram_bytes_transferred();
 210         info->ram->remaining = ram_bytes_remaining();
 211         info->ram->total = ram_bytes_total();
 212         info->ram->duplicate = dup_mig_pages_transferred();
 213         info->ram->skipped = skipped_mig_pages_transferred();
 214         info->ram->normal = norm_mig_pages_transferred();
 215         info->ram->normal_bytes = norm_mig_bytes_transferred();
 216         info->ram->dirty_pages_rate = s->dirty_pages_rate;
 217         info->ram->mbps = s->mbps;
 218
 219         if (blk_mig_active()) {
 220             info->has_disk = true;
 221             info->disk = g_malloc0(sizeof(*info->disk));
 222             info->disk->transferred = blk_mig_bytes_transferred();
 223             info->disk->remaining = blk_mig_bytes_remaining();
 224             info->disk->total = blk_mig_bytes_total();
 225         }
 226
 227         get_xbzrle_cache_stats(info);
 228         break;
 229     case MIG_STATE_COMPLETED:
 230         get_xbzrle_cache_stats(info);
 231
 232         info->has_status = true;
 233         info->status = g_strdup("completed");
 234         info->has_total_time = true;
 235         info->total_time = s->total_time;
 236         info->has_downtime = true;
 237         info->downtime = s->downtime;
 238         info->has_setup_time = true;
 239         info->setup_time = s->setup_time;
 240
 241         info->has_ram = true;
 242         info->ram = g_malloc0(sizeof(*info->ram));
 243         info->ram->transferred = ram_bytes_transferred();
 244         info->ram->remaining = 0;
 245         info->ram->total = ram_bytes_total();
 246         info->ram->duplicate = dup_mig_pages_transferred();
 247         info->ram->skipped = skipped_mig_pages_transferred();
 248         info->ram->normal = norm_mig_pages_transferred();
 249         info->ram->normal_bytes = norm_mig_bytes_transferred();
 250         info->ram->mbps = s->mbps;
 251         break;
 252     case MIG_STATE_ERROR:
 253         info->has_status = true;
 254         info->status = g_strdup("failed");
 255         break;
 256     case MIG_STATE_CANCELLED:
 257         info->has_status = true;
 258         info->status = g_strdup("cancelled");
 259         break;
 260     }
 261
 262     return info;
 263 }
 264
 265 void qmp_migrate_set_capabilities(MigrationCapabilityStatusList *params,
 266                                   Error **errp)
 267 {
 268     MigrationState *s = migrate_get_current();
 269     MigrationCapabilityStatusList *cap;
 270
 271     if (s->state == MIG_STATE_ACTIVE || s->state == MIG_STATE_SETUP) {
 272         error_set(errp, QERR_MIGRATION_ACTIVE);
 273         return;
 274     }
 275
 276     for (cap = params; cap; cap = cap->next) {
 277         s->enabled_capabilities[cap->value->capability] = cap->value->state;
 278     }
 279 }
 280
 281 /* shared migration helpers */
 282
 283 static void migrate_set_state(MigrationState *s, int old_state, int new_state)
 284 {
 285     if (atomic_cmpxchg(&s->state, old_state, new_state) == new_state) {
 286         trace_migrate_set_state(new_state);
 287     }
 288 }
 289
 290 static void migrate_fd_cleanup(void *opaque)
 291 {
 292     MigrationState *s = opaque;
 293
 294     qemu_bh_delete(s->cleanup_bh);
 295     s->cleanup_bh = NULL;
 296
 297     if (s->file) {
 298         trace_migrate_fd_cleanup();
 299         qemu_mutex_unlock_iothread();
 300         qemu_thread_join(&s->thread);
 301         qemu_mutex_lock_iothread();
 302
 303         qemu_fclose(s->file);
 304         s->file = NULL;
 305     }
 306
 307     assert(s->state != MIG_STATE_ACTIVE);
 308
 309     if (s->state != MIG_STATE_COMPLETED) {
 310         qemu_savevm_state_cancel();
 311         if (s->state == MIG_STATE_CANCELLING) {
 312             migrate_set_state(s, MIG_STATE_CANCELLING, MIG_STATE_CANCELLED);
 313         }
 314     }
 315
 316     notifier_list_notify(&migration_state_notifiers, s);
 317 }
 318
 319 void migrate_fd_error(MigrationState *s)
 320 {
 321     trace_migrate_fd_error();
 322     assert(s->file == NULL);
 323     s->state = MIG_STATE_ERROR;
 324     trace_migrate_set_state(MIG_STATE_ERROR);
 325     notifier_list_notify(&migration_state_notifiers, s);
 326 }
 327
 328 static void migrate_fd_cancel(MigrationState *s)
 329 {
 330     int old_state ;
 331     trace_migrate_fd_cancel();
 332
 333     do {
 334         old_state = s->state;
 335         if (old_state != MIG_STATE_SETUP && old_state != MIG_STATE_ACTIVE) {
 336             break;
 337         }
 338         migrate_set_state(s, old_state, MIG_STATE_CANCELLING);
 339     } while (s->state != MIG_STATE_CANCELLING);
 340 }
 341
 342 void add_migration_state_change_notifier(Notifier *notify)
 343 {
 344     notifier_list_add(&migration_state_notifiers, notify);
 345 }
 346
 347 void remove_migration_state_change_notifier(Notifier *notify)
 348 {
 349     notifier_remove(notify);
 350 }
 351
 352 bool migration_in_setup(MigrationState *s)
 353 {
 354     return s->state == MIG_STATE_SETUP;
 355 }
 356
 357 bool migration_has_finished(MigrationState *s)
 358 {
 359     return s->state == MIG_STATE_COMPLETED;
 360 }
 361
 362 bool migration_has_failed(MigrationState *s)
 363 {
 364     return (s->state == MIG_STATE_CANCELLED ||
 365             s->state == MIG_STATE_ERROR);
 366 }
 367
 368 static MigrationState *migrate_init(const MigrationParams *params)
 369 {
 370     MigrationState *s = migrate_get_current();
 371     int64_t bandwidth_limit = s->bandwidth_limit;
 372     bool enabled_capabilities[MIGRATION_CAPABILITY_MAX];
 373     int64_t xbzrle_cache_size = s->xbzrle_cache_size;
 374
 375     memcpy(enabled_capabilities, s->enabled_capabilities,
 376            sizeof(enabled_capabilities));
 377
 378     memset(s, 0, sizeof(*s));
 379     s->params = *params;
 380     memcpy(s->enabled_capabilities, enabled_capabilities,
 381            sizeof(enabled_capabilities));
 382     s->xbzrle_cache_size = xbzrle_cache_size;
 383
 384     s->bandwidth_limit = bandwidth_limit;
 385     s->state = MIG_STATE_SETUP;
 386     trace_migrate_set_state(MIG_STATE_SETUP);
 387
 388     s->total_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
 389     return s;
 390 }
 391
 392 static GSList *migration_blockers;
 393
 394 void migrate_add_blocker(Error *reason)
 395 {
 396     migration_blockers = g_slist_prepend(migration_blockers, reason);
 397 }
 398
 399 void migrate_del_blocker(Error *reason)
 400 {
 401     migration_blockers = g_slist_remove(migration_blockers, reason);
 402 }
 403
 404 void qmp_migrate(const char *uri, bool has_blk, bool blk,
 405                  bool has_inc, bool inc, bool has_detach, bool detach,
 406                  Error **errp)
 407 {
 408     Error *local_err = NULL;
 409     MigrationState *s = migrate_get_current();
 410     MigrationParams params;
 411     const char *p;
 412
 413     params.blk = has_blk && blk;
 414     params.shared = has_inc && inc;
 415
 416     if (s->state == MIG_STATE_ACTIVE || s->state == MIG_STATE_SETUP ||
 417         s->state == MIG_STATE_CANCELLING) {
 418         error_set(errp, QERR_MIGRATION_ACTIVE);
 419         return;
 420     }
 421
 422     if (qemu_savevm_state_blocked(errp)) {
 423         return;
 424     }
 425
 426     if (migration_blockers) {
 427         *errp = error_copy(migration_blockers->data);
 428         return;
 429     }
 430
 431     s = migrate_init(&params);
 432
 433     if (strstart(uri, "tcp:", &p)) {
 434         tcp_start_outgoing_migration(s, p, &local_err);
 435 #ifdef CONFIG_RDMA
 436     } else if (strstart(uri, "rdma:", &p)) {
 437         rdma_start_outgoing_migration(s, p, &local_err);
 438 #endif
 439 #if !defined(WIN32)
 440     } else if (strstart(uri, "exec:", &p)) {
 441         exec_start_outgoing_migration(s, p, &local_err);
 442     } else if (strstart(uri, "unix:", &p)) {
 443         unix_start_outgoing_migration(s, p, &local_err);
 444     } else if (strstart(uri, "fd:", &p)) {
 445         fd_start_outgoing_migration(s, p, &local_err);
 446 #endif
 447     } else {
 448         error_set(errp, QERR_INVALID_PARAMETER_VALUE, "uri", "a valid migration protocol");
 449         s->state = MIG_STATE_ERROR;
 450         return;
 451     }
 452
 453     if (local_err) {
 454         migrate_fd_error(s);
 455         error_propagate(errp, local_err);
 456         return;
 457     }
 458 }
 459
 460 void qmp_migrate_cancel(Error **errp)
 461 {
 462     migrate_fd_cancel(migrate_get_current());
 463 }
 464
 465 void qmp_migrate_set_cache_size(int64_t value, Error **errp)
 466 {
 467     MigrationState *s = migrate_get_current();
 468     int64_t new_size;
 469
 470     /* Check for truncation */
 471     if (value != (size_t)value) {
 472         error_set(errp, QERR_INVALID_PARAMETER_VALUE, "cache size",
 473                   "exceeding address space");
 474         return;
 475     }
 476
 477     /* Cache should not be larger than guest ram size */
 478     if (value > ram_bytes_total()) {
 479         error_set(errp, QERR_INVALID_PARAMETER_VALUE, "cache size",
 480                   "exceeds guest ram size ");
 481         return;
 482     }
 483
 484     new_size = xbzrle_cache_resize(value);
 485     if (new_size < 0) {
 486         error_set(errp, QERR_INVALID_PARAMETER_VALUE, "cache size",
 487                   "is smaller than page size");
 488         return;
 489     }
 490
 491     s->xbzrle_cache_size = new_size;
 492 }
 493
 494 int64_t qmp_query_migrate_cache_size(Error **errp)
 495 {
 496     return migrate_xbzrle_cache_size();
 497 }
 498
 499 void qmp_migrate_set_speed(int64_t value, Error **errp)
 500 {
 501     MigrationState *s;
 502
 503     if (value < 0) {
 504         value = 0;
 505     }
 506     if (value > SIZE_MAX) {
 507         value = SIZE_MAX;
 508     }
 509
 510     s = migrate_get_current();
 511     s->bandwidth_limit = value;
 512     if (s->file) {
 513         qemu_file_set_rate_limit(s->file, s->bandwidth_limit / XFER_LIMIT_RATIO);
 514     }
 515 }
 516
 517 void qmp_migrate_set_downtime(double value, Error **errp)
 518 {
 519     value *= 1e9;
 520     value = MAX(0, MIN(UINT64_MAX, value));
 521     max_downtime = (uint64_t)value;
 522 }
 523
 524 bool migrate_rdma_pin_all(void)
 525 {
 526     MigrationState *s;
 527
 528     s = migrate_get_current();
 529
 530     return s->enabled_capabilities[MIGRATION_CAPABILITY_RDMA_PIN_ALL];
 531 }
 532
 533 bool migrate_auto_converge(void)
 534 {
 535     MigrationState *s;
 536
 537     s = migrate_get_current();
 538
 539     return s->enabled_capabilities[MIGRATION_CAPABILITY_AUTO_CONVERGE];
 540 }
 541
 542 bool migrate_zero_blocks(void)
 543 {
 544     MigrationState *s;
 545
 546     s = migrate_get_current();
 547
 548     return s->enabled_capabilities[MIGRATION_CAPABILITY_ZERO_BLOCKS];
 549 }
 550
 551 int migrate_use_xbzrle(void)
 552 {
 553     MigrationState *s;
 554
 555     s = migrate_get_current();
 556
 557     return s->enabled_capabilities[MIGRATION_CAPABILITY_XBZRLE];
 558 }
 559
 560 int64_t migrate_xbzrle_cache_size(void)
 561 {
 562     MigrationState *s;
 563
 564     s = migrate_get_current();
 565
 566     return s->xbzrle_cache_size;
 567 }
 568
 569 /* migration thread support */
 570
 571 static void *migration_thread(void *opaque)
 572 {
 573     MigrationState *s = opaque;
 574     int64_t initial_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
 575     int64_t setup_start = qemu_clock_get_ms(QEMU_CLOCK_HOST);
 576     int64_t initial_bytes = 0;
 577     int64_t max_size = 0;
 578     int64_t start_time = initial_time;
 579     bool old_vm_running = false;
 580
 581     qemu_savevm_state_begin(s->file, &s->params);
 582
 583     s->setup_time = qemu_clock_get_ms(QEMU_CLOCK_HOST) - setup_start;
 584     migrate_set_state(s, MIG_STATE_SETUP, MIG_STATE_ACTIVE);
 585
 586     while (s->state == MIG_STATE_ACTIVE) {
 587         int64_t current_time;
 588         uint64_t pending_size;
 589
 590         if (!qemu_file_rate_limit(s->file)) {
 591             pending_size = qemu_savevm_state_pending(s->file, max_size);
 592             trace_migrate_pending(pending_size, max_size);
 593             if (pending_size && pending_size >= max_size) {
 594                 qemu_savevm_state_iterate(s->file);
 595             } else {
 596                 int ret;
 597
 598                 qemu_mutex_lock_iothread();
 599                 start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
 600                 qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER);
 601                 old_vm_running = runstate_is_running();
 602
 603                 ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
 604                 if (ret >= 0) {
 605                     qemu_file_set_rate_limit(s->file, INT64_MAX);
 606                     qemu_savevm_state_complete(s->file);
 607                 }
 608                 qemu_mutex_unlock_iothread();
 609
 610                 if (ret < 0) {
 611                     migrate_set_state(s, MIG_STATE_ACTIVE, MIG_STATE_ERROR);
 612                     break;
 613                 }
 614
 615                 if (!qemu_file_get_error(s->file)) {
 616                     migrate_set_state(s, MIG_STATE_ACTIVE, MIG_STATE_COMPLETED);
 617                     break;
 618                 }
 619             }
 620         }
 621
 622         if (qemu_file_get_error(s->file)) {
 623             migrate_set_state(s, MIG_STATE_ACTIVE, MIG_STATE_ERROR);
 624             break;
 625         }
 626         current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
 627         if (current_time >= initial_time + BUFFER_DELAY) {
 628             uint64_t transferred_bytes = qemu_ftell(s->file) - initial_bytes;
 629             uint64_t time_spent = current_time - initial_time;
 630             double bandwidth = transferred_bytes / time_spent;
 631             max_size = bandwidth * migrate_max_downtime() / 1000000;
 632
 633             s->mbps = time_spent ? (((double) transferred_bytes * 8.0) /
 634                     ((double) time_spent / 1000.0)) / 1000.0 / 1000.0 : -1;
 635
 636             trace_migrate_transferred(transferred_bytes, time_spent,
 637                                       bandwidth, max_size);
 638             /* if we haven't sent anything, we don't want to recalculate
 639                10000 is a small enough number for our purposes */
 640             if (s->dirty_bytes_rate && transferred_bytes > 10000) {
 641                 s->expected_downtime = s->dirty_bytes_rate / bandwidth;
 642             }
 643
 644             qemu_file_reset_rate_limit(s->file);
 645             initial_time = current_time;
 646             initial_bytes = qemu_ftell(s->file);
 647         }
 648         if (qemu_file_rate_limit(s->file)) {
 649             /* usleep expects microseconds */
 650             g_usleep((initial_time + BUFFER_DELAY - current_time)*1000);
 651         }
 652     }
 653
 654     qemu_mutex_lock_iothread();
 655     if (s->state == MIG_STATE_COMPLETED) {
 656         int64_t end_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
 657         s->total_time = end_time - s->total_time;
 658         s->downtime = end_time - start_time;
 659         runstate_set(RUN_STATE_POSTMIGRATE);
 660     } else {
 661         if (old_vm_running) {
 662             vm_start();
 663         }
 664     }
 665     qemu_bh_schedule(s->cleanup_bh);
 666     qemu_mutex_unlock_iothread();
 667
 668     return NULL;
 669 }
 670
 671 void migrate_fd_connect(MigrationState *s)
 672 {
 673     s->state = MIG_STATE_SETUP;
 674     trace_migrate_set_state(MIG_STATE_SETUP);
 675
 676     /* This is a best 1st approximation. ns to ms */
 677     s->expected_downtime = max_downtime/1000000;
 678     s->cleanup_bh = qemu_bh_new(migrate_fd_cleanup, s);
 679
 680     qemu_file_set_rate_limit(s->file,
 681                              s->bandwidth_limit / XFER_LIMIT_RATIO);
 682
 683     /* Notify before starting migration thread */
 684     notifier_list_notify(&migration_state_notifiers, s);
 685
 686     qemu_thread_create(&s->thread, "migration", migration_thread, s,
 687                        QEMU_THREAD_JOINABLE);
 688 }