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 //#define DEBUG_MIGRATION
  30
  31 #ifdef DEBUG_MIGRATION
  32 #define DPRINTF(fmt, ...) \
  33     do { printf("migration: " fmt, ## __VA_ARGS__); } while (0)
  34 #else
  35 #define DPRINTF(fmt, ...) \
  36     do { } while (0)
  37 #endif
  38
  39 enum {
  40     MIG_STATE_ERROR = -1,
  41     MIG_STATE_NONE,
  42     MIG_STATE_SETUP,
  43     MIG_STATE_CANCELLED,
  44     MIG_STATE_ACTIVE,
  45     MIG_STATE_COMPLETED,
  46 };
  47
  48 #define MAX_THROTTLE  (32 << 20)      /* Migration speed throttling */
  49
  50 /* Amount of time to allocate to each "chunk" of bandwidth-throttled
  51  * data. */
  52 #define BUFFER_DELAY     100
  53 #define XFER_LIMIT_RATIO (1000 / BUFFER_DELAY)
  54
  55 /* Migration XBZRLE default cache size */
  56 #define DEFAULT_MIGRATE_CACHE_SIZE (64 * 1024 * 1024)
  57
  58 static NotifierList migration_state_notifiers =
  59     NOTIFIER_LIST_INITIALIZER(migration_state_notifiers);
  60
  61 /* When we add fault tolerance, we could have several
  62    migrations at once.  For now we don't need to add
  63    dynamic creation of migration */
  64
  65 MigrationState *migrate_get_current(void)
  66 {
  67     static MigrationState current_migration = {
  68         .state = MIG_STATE_NONE,
  69         .bandwidth_limit = MAX_THROTTLE,
  70         .xbzrle_cache_size = DEFAULT_MIGRATE_CACHE_SIZE,
  71         .mbps = -1,
  72     };
  73
  74     return &current_migration;
  75 }
  76
  77 void qemu_start_incoming_migration(const char *uri, Error **errp)
  78 {
  79     const char *p;
  80
  81     if (strstart(uri, "tcp:", &p))
  82         tcp_start_incoming_migration(p, errp);
  83 #ifdef CONFIG_RDMA
  84     else if (strstart(uri, "x-rdma:", &p))
  85         rdma_start_incoming_migration(p, errp);
  86 #endif
  87 #if !defined(WIN32)
  88     else if (strstart(uri, "exec:", &p))
  89         exec_start_incoming_migration(p, errp);
  90     else if (strstart(uri, "unix:", &p))
  91         unix_start_incoming_migration(p, errp);
  92     else if (strstart(uri, "fd:", &p))
  93         fd_start_incoming_migration(p, errp);
  94 #endif
  95     else {
  96         error_setg(errp, "unknown migration protocol: %s", uri);
  97     }
  98 }
  99
 100 static void process_incoming_migration_co(void *opaque)
 101 {
 102     QEMUFile *f = opaque;
 103     int ret;
 104
 105     ret = qemu_loadvm_state(f);
 106     qemu_fclose(f);
 107     if (ret < 0) {
 108         fprintf(stderr, "load of migration failed\n");
 109         exit(EXIT_FAILURE);
 110     }
 111     qemu_announce_self();
 112     DPRINTF("successfully loaded vm state\n");
 113
 114     bdrv_clear_incoming_migration_all();
 115     /* Make sure all file formats flush their mutable metadata */
 116     bdrv_invalidate_cache_all();
 117
 118     if (autostart) {
 119         vm_start();
 120     } else {
 121         runstate_set(RUN_STATE_PAUSED);
 122     }
 123 }
 124
 125 void process_incoming_migration(QEMUFile *f)
 126 {
 127     Coroutine *co = qemu_coroutine_create(process_incoming_migration_co);
 128     int fd = qemu_get_fd(f);
 129
 130     assert(fd != -1);
 131     qemu_set_nonblock(fd);
 132     qemu_coroutine_enter(co, f);
 133 }
 134
 135 /* amount of nanoseconds we are willing to wait for migration to be down.
 136  * the choice of nanoseconds is because it is the maximum resolution that
 137  * get_clock() can achieve. It is an internal measure. All user-visible
 138  * units must be in seconds */
 139 static uint64_t max_downtime = 30000000;
 140
 141 uint64_t migrate_max_downtime(void)
 142 {
 143     return max_downtime;
 144 }
 145
 146 MigrationCapabilityStatusList *qmp_query_migrate_capabilities(Error **errp)
 147 {
 148     MigrationCapabilityStatusList *head = NULL;
 149     MigrationCapabilityStatusList *caps;
 150     MigrationState *s = migrate_get_current();
 151     int i;
 152
 153     caps = NULL; /* silence compiler warning */
 154     for (i = 0; i < MIGRATION_CAPABILITY_MAX; i++) {
 155         if (head == NULL) {
 156             head = g_malloc0(sizeof(*caps));
 157             caps = head;
 158         } else {
 159             caps->next = g_malloc0(sizeof(*caps));
 160             caps = caps->next;
 161         }
 162         caps->value =
 163             g_malloc(sizeof(*caps->value));
 164         caps->value->capability = i;
 165         caps->value->state = s->enabled_capabilities[i];
 166     }
 167
 168     return head;
 169 }
 170
 171 static void get_xbzrle_cache_stats(MigrationInfo *info)
 172 {
 173     if (migrate_use_xbzrle()) {
 174         info->has_xbzrle_cache = true;
 175         info->xbzrle_cache = g_malloc0(sizeof(*info->xbzrle_cache));
 176         info->xbzrle_cache->cache_size = migrate_xbzrle_cache_size();
 177         info->xbzrle_cache->bytes = xbzrle_mig_bytes_transferred();
 178         info->xbzrle_cache->pages = xbzrle_mig_pages_transferred();
 179         info->xbzrle_cache->cache_miss = xbzrle_mig_pages_cache_miss();
 180         info->xbzrle_cache->overflow = xbzrle_mig_pages_overflow();
 181     }
 182 }
 183
 184 MigrationInfo *qmp_query_migrate(Error **errp)
 185 {
 186     MigrationInfo *info = g_malloc0(sizeof(*info));
 187     MigrationState *s = migrate_get_current();
 188
 189     switch (s->state) {
 190     case MIG_STATE_NONE:
 191         /* no migration has happened ever */
 192         break;
 193     case MIG_STATE_SETUP:
 194         info->has_status = true;
 195         info->status = g_strdup("setup");
 196         info->has_total_time = false;
 197         break;
 198     case MIG_STATE_ACTIVE:
 199         info->has_status = true;
 200         info->status = g_strdup("active");
 201         info->has_total_time = true;
 202         info->total_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME)
 203             - s->total_time;
 204         info->has_expected_downtime = true;
 205         info->expected_downtime = s->expected_downtime;
 206         info->has_setup_time = true;
 207         info->setup_time = s->setup_time;
 208
 209         info->has_ram = true;
 210         info->ram = g_malloc0(sizeof(*info->ram));
 211         info->ram->transferred = ram_bytes_transferred();
 212         info->ram->remaining = ram_bytes_remaining();
 213         info->ram->total = ram_bytes_total();
 214         info->ram->duplicate = dup_mig_pages_transferred();
 215         info->ram->skipped = skipped_mig_pages_transferred();
 216         info->ram->normal = norm_mig_pages_transferred();
 217         info->ram->normal_bytes = norm_mig_bytes_transferred();
 218         info->ram->dirty_pages_rate = s->dirty_pages_rate;
 219         info->ram->mbps = s->mbps;
 220
 221         if (blk_mig_active()) {
 222             info->has_disk = true;
 223             info->disk = g_malloc0(sizeof(*info->disk));
 224             info->disk->transferred = blk_mig_bytes_transferred();
 225             info->disk->remaining = blk_mig_bytes_remaining();
 226             info->disk->total = blk_mig_bytes_total();
 227         }
 228
 229         get_xbzrle_cache_stats(info);
 230         break;
 231     case MIG_STATE_COMPLETED:
 232         get_xbzrle_cache_stats(info);
 233
 234         info->has_status = true;
 235         info->status = g_strdup("completed");
 236         info->has_total_time = true;
 237         info->total_time = s->total_time;
 238         info->has_downtime = true;
 239         info->downtime = s->downtime;
 240         info->has_setup_time = true;
 241         info->setup_time = s->setup_time;
 242
 243         info->has_ram = true;
 244         info->ram = g_malloc0(sizeof(*info->ram));
 245         info->ram->transferred = ram_bytes_transferred();
 246         info->ram->remaining = 0;
 247         info->ram->total = ram_bytes_total();
 248         info->ram->duplicate = dup_mig_pages_transferred();
 249         info->ram->skipped = skipped_mig_pages_transferred();
 250         info->ram->normal = norm_mig_pages_transferred();
 251         info->ram->normal_bytes = norm_mig_bytes_transferred();
 252         info->ram->mbps = s->mbps;
 253         break;
 254     case MIG_STATE_ERROR:
 255         info->has_status = true;
 256         info->status = g_strdup("failed");
 257         break;
 258     case MIG_STATE_CANCELLED:
 259         info->has_status = true;
 260         info->status = g_strdup("cancelled");
 261         break;
 262     }
 263
 264     return info;
 265 }
 266
 267 void qmp_migrate_set_capabilities(MigrationCapabilityStatusList *params,
 268                                   Error **errp)
 269 {
 270     MigrationState *s = migrate_get_current();
 271     MigrationCapabilityStatusList *cap;
 272
 273     if (s->state == MIG_STATE_ACTIVE || s->state == MIG_STATE_SETUP) {
 274         error_set(errp, QERR_MIGRATION_ACTIVE);
 275         return;
 276     }
 277
 278     for (cap = params; cap; cap = cap->next) {
 279         s->enabled_capabilities[cap->value->capability] = cap->value->state;
 280     }
 281 }
 282
 283 /* shared migration helpers */
 284
 285 static void migrate_fd_cleanup(void *opaque)
 286 {
 287     MigrationState *s = opaque;
 288
 289     qemu_bh_delete(s->cleanup_bh);
 290     s->cleanup_bh = NULL;
 291
 292     if (s->file) {
 293         DPRINTF("closing file\n");
 294         qemu_mutex_unlock_iothread();
 295         qemu_thread_join(&s->thread);
 296         qemu_mutex_lock_iothread();
 297
 298         qemu_fclose(s->file);
 299         s->file = NULL;
 300     }
 301
 302     assert(s->state != MIG_STATE_ACTIVE);
 303
 304     if (s->state != MIG_STATE_COMPLETED) {
 305         qemu_savevm_state_cancel();
 306     }
 307
 308     notifier_list_notify(&migration_state_notifiers, s);
 309 }
 310
 311 static void migrate_set_state(MigrationState *s, int old_state, int new_state)
 312 {
 313     if (atomic_cmpxchg(&s->state, old_state, new_state) == new_state) {
 314         trace_migrate_set_state(new_state);
 315     }
 316 }
 317
 318 void migrate_fd_error(MigrationState *s)
 319 {
 320     DPRINTF("setting error state\n");
 321     assert(s->file == NULL);
 322     s->state = MIG_STATE_ERROR;
 323     trace_migrate_set_state(MIG_STATE_ERROR);
 324     notifier_list_notify(&migration_state_notifiers, s);
 325 }
 326
 327 static void migrate_fd_cancel(MigrationState *s)
 328 {
 329     DPRINTF("cancelling migration\n");
 330
 331     migrate_set_state(s, s->state, MIG_STATE_CANCELLED);
 332 }
 333
 334 void add_migration_state_change_notifier(Notifier *notify)
 335 {
 336     notifier_list_add(&migration_state_notifiers, notify);
 337 }
 338
 339 void remove_migration_state_change_notifier(Notifier *notify)
 340 {
 341     notifier_remove(notify);
 342 }
 343
 344 bool migration_in_setup(MigrationState *s)
 345 {
 346     return s->state == MIG_STATE_SETUP;
 347 }
 348
 349 bool migration_has_finished(MigrationState *s)
 350 {
 351     return s->state == MIG_STATE_COMPLETED;
 352 }
 353
 354 bool migration_has_failed(MigrationState *s)
 355 {
 356     return (s->state == MIG_STATE_CANCELLED ||
 357             s->state == MIG_STATE_ERROR);
 358 }
 359
 360 static MigrationState *migrate_init(const MigrationParams *params)
 361 {
 362     MigrationState *s = migrate_get_current();
 363     int64_t bandwidth_limit = s->bandwidth_limit;
 364     bool enabled_capabilities[MIGRATION_CAPABILITY_MAX];
 365     int64_t xbzrle_cache_size = s->xbzrle_cache_size;
 366
 367     memcpy(enabled_capabilities, s->enabled_capabilities,
 368            sizeof(enabled_capabilities));
 369
 370     memset(s, 0, sizeof(*s));
 371     s->params = *params;
 372     memcpy(s->enabled_capabilities, enabled_capabilities,
 373            sizeof(enabled_capabilities));
 374     s->xbzrle_cache_size = xbzrle_cache_size;
 375
 376     s->bandwidth_limit = bandwidth_limit;
 377     s->state = MIG_STATE_SETUP;
 378     trace_migrate_set_state(MIG_STATE_SETUP);
 379
 380     s->total_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
 381     return s;
 382 }
 383
 384 static GSList *migration_blockers;
 385
 386 void migrate_add_blocker(Error *reason)
 387 {
 388     migration_blockers = g_slist_prepend(migration_blockers, reason);
 389 }
 390
 391 void migrate_del_blocker(Error *reason)
 392 {
 393     migration_blockers = g_slist_remove(migration_blockers, reason);
 394 }
 395
 396 void qmp_migrate(const char *uri, bool has_blk, bool blk,
 397                  bool has_inc, bool inc, bool has_detach, bool detach,
 398                  Error **errp)
 399 {
 400     Error *local_err = NULL;
 401     MigrationState *s = migrate_get_current();
 402     MigrationParams params;
 403     const char *p;
 404
 405     params.blk = has_blk && blk;
 406     params.shared = has_inc && inc;
 407
 408     if (s->state == MIG_STATE_ACTIVE || s->state == MIG_STATE_SETUP) {
 409         error_set(errp, QERR_MIGRATION_ACTIVE);
 410         return;
 411     }
 412
 413     if (qemu_savevm_state_blocked(errp)) {
 414         return;
 415     }
 416
 417     if (migration_blockers) {
 418         *errp = error_copy(migration_blockers->data);
 419         return;
 420     }
 421
 422     s = migrate_init(&params);
 423
 424     if (strstart(uri, "tcp:", &p)) {
 425         tcp_start_outgoing_migration(s, p, &local_err);
 426 #ifdef CONFIG_RDMA
 427     } else if (strstart(uri, "x-rdma:", &p)) {
 428         rdma_start_outgoing_migration(s, p, &local_err);
 429 #endif
 430 #if !defined(WIN32)
 431     } else if (strstart(uri, "exec:", &p)) {
 432         exec_start_outgoing_migration(s, p, &local_err);
 433     } else if (strstart(uri, "unix:", &p)) {
 434         unix_start_outgoing_migration(s, p, &local_err);
 435     } else if (strstart(uri, "fd:", &p)) {
 436         fd_start_outgoing_migration(s, p, &local_err);
 437 #endif
 438     } else {
 439         error_set(errp, QERR_INVALID_PARAMETER_VALUE, "uri", "a valid migration protocol");
 440         return;
 441     }
 442
 443     if (local_err) {
 444         migrate_fd_error(s);
 445         error_propagate(errp, local_err);
 446         return;
 447     }
 448 }
 449
 450 void qmp_migrate_cancel(Error **errp)
 451 {
 452     migrate_fd_cancel(migrate_get_current());
 453 }
 454
 455 void qmp_migrate_set_cache_size(int64_t value, Error **errp)
 456 {
 457     MigrationState *s = migrate_get_current();
 458
 459     /* Check for truncation */
 460     if (value != (size_t)value) {
 461         error_set(errp, QERR_INVALID_PARAMETER_VALUE, "cache size",
 462                   "exceeding address space");
 463         return;
 464     }
 465
 466     s->xbzrle_cache_size = xbzrle_cache_resize(value);
 467 }
 468
 469 int64_t qmp_query_migrate_cache_size(Error **errp)
 470 {
 471     return migrate_xbzrle_cache_size();
 472 }
 473
 474 void qmp_migrate_set_speed(int64_t value, Error **errp)
 475 {
 476     MigrationState *s;
 477
 478     if (value < 0) {
 479         value = 0;
 480     }
 481     if (value > SIZE_MAX) {
 482         value = SIZE_MAX;
 483     }
 484
 485     s = migrate_get_current();
 486     s->bandwidth_limit = value;
 487     if (s->file) {
 488         qemu_file_set_rate_limit(s->file, s->bandwidth_limit / XFER_LIMIT_RATIO);
 489     }
 490 }
 491
 492 void qmp_migrate_set_downtime(double value, Error **errp)
 493 {
 494     value *= 1e9;
 495     value = MAX(0, MIN(UINT64_MAX, value));
 496     max_downtime = (uint64_t)value;
 497 }
 498
 499 bool migrate_rdma_pin_all(void)
 500 {
 501     MigrationState *s;
 502
 503     s = migrate_get_current();
 504
 505     return s->enabled_capabilities[MIGRATION_CAPABILITY_X_RDMA_PIN_ALL];
 506 }
 507
 508 bool migrate_auto_converge(void)
 509 {
 510     MigrationState *s;
 511
 512     s = migrate_get_current();
 513
 514     return s->enabled_capabilities[MIGRATION_CAPABILITY_AUTO_CONVERGE];
 515 }
 516
 517 bool migrate_zero_blocks(void)
 518 {
 519     MigrationState *s;
 520
 521     s = migrate_get_current();
 522
 523     return s->enabled_capabilities[MIGRATION_CAPABILITY_ZERO_BLOCKS];
 524 }
 525
 526 int migrate_use_xbzrle(void)
 527 {
 528     MigrationState *s;
 529
 530     s = migrate_get_current();
 531
 532     return s->enabled_capabilities[MIGRATION_CAPABILITY_XBZRLE];
 533 }
 534
 535 int64_t migrate_xbzrle_cache_size(void)
 536 {
 537     MigrationState *s;
 538
 539     s = migrate_get_current();
 540
 541     return s->xbzrle_cache_size;
 542 }
 543
 544 /* migration thread support */
 545
 546 static void *migration_thread(void *opaque)
 547 {
 548     MigrationState *s = opaque;
 549     int64_t initial_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
 550     int64_t setup_start = qemu_clock_get_ms(QEMU_CLOCK_HOST);
 551     int64_t initial_bytes = 0;
 552     int64_t max_size = 0;
 553     int64_t start_time = initial_time;
 554     bool old_vm_running = false;
 555
 556     DPRINTF("beginning savevm\n");
 557     qemu_savevm_state_begin(s->file, &s->params);
 558
 559     s->setup_time = qemu_clock_get_ms(QEMU_CLOCK_HOST) - setup_start;
 560     migrate_set_state(s, MIG_STATE_SETUP, MIG_STATE_ACTIVE);
 561
 562     DPRINTF("setup complete\n");
 563
 564     while (s->state == MIG_STATE_ACTIVE) {
 565         int64_t current_time;
 566         uint64_t pending_size;
 567
 568         if (!qemu_file_rate_limit(s->file)) {
 569             DPRINTF("iterate\n");
 570             pending_size = qemu_savevm_state_pending(s->file, max_size);
 571             DPRINTF("pending size %" PRIu64 " max %" PRIu64 "\n",
 572                     pending_size, max_size);
 573             if (pending_size && pending_size >= max_size) {
 574                 qemu_savevm_state_iterate(s->file);
 575             } else {
 576                 int ret;
 577
 578                 DPRINTF("done iterating\n");
 579                 qemu_mutex_lock_iothread();
 580                 start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
 581                 qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER);
 582                 old_vm_running = runstate_is_running();
 583
 584                 ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
 585                 if (ret >= 0) {
 586                     qemu_file_set_rate_limit(s->file, INT_MAX);
 587                     qemu_savevm_state_complete(s->file);
 588                 }
 589                 qemu_mutex_unlock_iothread();
 590
 591                 if (ret < 0) {
 592                     migrate_set_state(s, MIG_STATE_ACTIVE, MIG_STATE_ERROR);
 593                     break;
 594                 }
 595
 596                 if (!qemu_file_get_error(s->file)) {
 597                     migrate_set_state(s, MIG_STATE_ACTIVE, MIG_STATE_COMPLETED);
 598                     break;
 599                 }
 600             }
 601         }
 602
 603         if (qemu_file_get_error(s->file)) {
 604             migrate_set_state(s, MIG_STATE_ACTIVE, MIG_STATE_ERROR);
 605             break;
 606         }
 607         current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
 608         if (current_time >= initial_time + BUFFER_DELAY) {
 609             uint64_t transferred_bytes = qemu_ftell(s->file) - initial_bytes;
 610             uint64_t time_spent = current_time - initial_time;
 611             double bandwidth = transferred_bytes / time_spent;
 612             max_size = bandwidth * migrate_max_downtime() / 1000000;
 613
 614             s->mbps = time_spent ? (((double) transferred_bytes * 8.0) /
 615                     ((double) time_spent / 1000.0)) / 1000.0 / 1000.0 : -1;
 616
 617             DPRINTF("transferred %" PRIu64 " time_spent %" PRIu64
 618                     " bandwidth %g max_size %" PRId64 "\n",
 619                     transferred_bytes, time_spent, bandwidth, max_size);
 620             /* if we haven't sent anything, we don't want to recalculate
 621                10000 is a small enough number for our purposes */
 622             if (s->dirty_bytes_rate && transferred_bytes > 10000) {
 623                 s->expected_downtime = s->dirty_bytes_rate / bandwidth;
 624             }
 625
 626             qemu_file_reset_rate_limit(s->file);
 627             initial_time = current_time;
 628             initial_bytes = qemu_ftell(s->file);
 629         }
 630         if (qemu_file_rate_limit(s->file)) {
 631             /* usleep expects microseconds */
 632             g_usleep((initial_time + BUFFER_DELAY - current_time)*1000);
 633         }
 634     }
 635
 636     qemu_mutex_lock_iothread();
 637     if (s->state == MIG_STATE_COMPLETED) {
 638         int64_t end_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
 639         s->total_time = end_time - s->total_time;
 640         s->downtime = end_time - start_time;
 641         runstate_set(RUN_STATE_POSTMIGRATE);
 642     } else {
 643         if (old_vm_running) {
 644             vm_start();
 645         }
 646     }
 647     qemu_bh_schedule(s->cleanup_bh);
 648     qemu_mutex_unlock_iothread();
 649
 650     return NULL;
 651 }
 652
 653 void migrate_fd_connect(MigrationState *s)
 654 {
 655     s->state = MIG_STATE_SETUP;
 656     trace_migrate_set_state(MIG_STATE_SETUP);
 657
 658     /* This is a best 1st approximation. ns to ms */
 659     s->expected_downtime = max_downtime/1000000;
 660     s->cleanup_bh = qemu_bh_new(migrate_fd_cleanup, s);
 661
 662     qemu_file_set_rate_limit(s->file,
 663                              s->bandwidth_limit / XFER_LIMIT_RATIO);
 664
 665     /* Notify before starting migration thread */
 666     notifier_list_notify(&migration_state_notifiers, s);
 667
 668     qemu_thread_create(&s->thread, migration_thread, s,
 669                        QEMU_THREAD_JOINABLE);
 670 }