migration/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/error-report.h"
  18 #include "qemu/main-loop.h"
  19 #include "migration/migration.h"
  20 #include "monitor/monitor.h"
  21 #include "migration/qemu-file.h"
  22 #include "sysemu/sysemu.h"
  23 #include "block/block.h"
  24 #include "qemu/sockets.h"
  25 #include "migration/block.h"
  26 #include "qemu/thread.h"
  27 #include "qmp-commands.h"
  28 #include "trace.h"
  29
  30 #define MAX_THROTTLE  (32 << 20)      /* Migration speed throttling */
  31
  32 /* Amount of time to allocate to each "chunk" of bandwidth-throttled
  33  * data. */
  34 #define BUFFER_DELAY     100
  35 #define XFER_LIMIT_RATIO (1000 / BUFFER_DELAY)
  36
  37 /* Default compression thread count */
  38 #define DEFAULT_MIGRATE_COMPRESS_THREAD_COUNT 8
  39 /* Default decompression thread count, usually decompression is at
  40  * least 4 times as fast as compression.*/
  41 #define DEFAULT_MIGRATE_DECOMPRESS_THREAD_COUNT 2
  42 /*0: means nocompress, 1: best speed, ... 9: best compress ratio */
  43 #define DEFAULT_MIGRATE_COMPRESS_LEVEL 1
  44
  45 /* Migration XBZRLE default cache size */
  46 #define DEFAULT_MIGRATE_CACHE_SIZE (64 * 1024 * 1024)
  47
  48 static NotifierList migration_state_notifiers =
  49     NOTIFIER_LIST_INITIALIZER(migration_state_notifiers);
  50
  51 static bool deferred_incoming;
  52
  53 /* When we add fault tolerance, we could have several
  54    migrations at once.  For now we don't need to add
  55    dynamic creation of migration */
  56
  57 /* For outgoing */
  58 MigrationState *migrate_get_current(void)
  59 {
  60     static MigrationState current_migration = {
  61         .state = MIGRATION_STATUS_NONE,
  62         .bandwidth_limit = MAX_THROTTLE,
  63         .xbzrle_cache_size = DEFAULT_MIGRATE_CACHE_SIZE,
  64         .mbps = -1,
  65         .parameters[MIGRATION_PARAMETER_COMPRESS_LEVEL] =
  66                 DEFAULT_MIGRATE_COMPRESS_LEVEL,
  67         .parameters[MIGRATION_PARAMETER_COMPRESS_THREADS] =
  68                 DEFAULT_MIGRATE_COMPRESS_THREAD_COUNT,
  69         .parameters[MIGRATION_PARAMETER_DECOMPRESS_THREADS] =
  70                 DEFAULT_MIGRATE_DECOMPRESS_THREAD_COUNT,
  71     };
  72
  73     return &current_migration;
  74 }
  75
  76 /* For incoming */
  77 static MigrationIncomingState *mis_current;
  78
  79 MigrationIncomingState *migration_incoming_get_current(void)
  80 {
  81     return mis_current;
  82 }
  83
  84 MigrationIncomingState *migration_incoming_state_new(QEMUFile* f)
  85 {
  86     mis_current = g_malloc0(sizeof(MigrationIncomingState));
  87     mis_current->file = f;
  88     QLIST_INIT(&mis_current->loadvm_handlers);
  89
  90     return mis_current;
  91 }
  92
  93 void migration_incoming_state_destroy(void)
  94 {
  95     loadvm_free_handlers(mis_current);
  96     g_free(mis_current);
  97     mis_current = NULL;
  98 }
  99
 100 /*
 101  * Called on -incoming with a defer: uri.
 102  * The migration can be started later after any parameters have been
 103  * changed.
 104  */
 105 static void deferred_incoming_migration(Error **errp)
 106 {
 107     if (deferred_incoming) {
 108         error_setg(errp, "Incoming migration already deferred");
 109     }
 110     deferred_incoming = true;
 111 }
 112
 113 void qemu_start_incoming_migration(const char *uri, Error **errp)
 114 {
 115     const char *p;
 116
 117     if (!strcmp(uri, "defer")) {
 118         deferred_incoming_migration(errp);
 119     } else if (strstart(uri, "tcp:", &p)) {
 120         tcp_start_incoming_migration(p, errp);
 121 #ifdef CONFIG_RDMA
 122     } else if (strstart(uri, "rdma:", &p)) {
 123         rdma_start_incoming_migration(p, errp);
 124 #endif
 125 #if !defined(WIN32)
 126     } else if (strstart(uri, "exec:", &p)) {
 127         exec_start_incoming_migration(p, errp);
 128     } else if (strstart(uri, "unix:", &p)) {
 129         unix_start_incoming_migration(p, errp);
 130     } else if (strstart(uri, "fd:", &p)) {
 131         fd_start_incoming_migration(p, errp);
 132 #endif
 133     } else {
 134         error_setg(errp, "unknown migration protocol: %s", uri);
 135     }
 136 }
 137
 138 static void process_incoming_migration_co(void *opaque)
 139 {
 140     QEMUFile *f = opaque;
 141     Error *local_err = NULL;
 142     int ret;
 143
 144     migration_incoming_state_new(f);
 145
 146     ret = qemu_loadvm_state(f);
 147
 148     qemu_fclose(f);
 149     free_xbzrle_decoded_buf();
 150     migration_incoming_state_destroy();
 151
 152     if (ret < 0) {
 153         error_report("load of migration failed: %s", strerror(-ret));
 154         migrate_decompress_threads_join();
 155         exit(EXIT_FAILURE);
 156     }
 157     qemu_announce_self();
 158
 159     /* Make sure all file formats flush their mutable metadata */
 160     bdrv_invalidate_cache_all(&local_err);
 161     if (local_err) {
 162         error_report_err(local_err);
 163         migrate_decompress_threads_join();
 164         exit(EXIT_FAILURE);
 165     }
 166
 167     if (autostart) {
 168         vm_start();
 169     } else {
 170         runstate_set(RUN_STATE_PAUSED);
 171     }
 172     migrate_decompress_threads_join();
 173 }
 174
 175 void process_incoming_migration(QEMUFile *f)
 176 {
 177     Coroutine *co = qemu_coroutine_create(process_incoming_migration_co);
 178     int fd = qemu_get_fd(f);
 179
 180     assert(fd != -1);
 181     migrate_decompress_threads_create();
 182     qemu_set_nonblock(fd);
 183     qemu_coroutine_enter(co, f);
 184 }
 185
 186 /* amount of nanoseconds we are willing to wait for migration to be down.
 187  * the choice of nanoseconds is because it is the maximum resolution that
 188  * get_clock() can achieve. It is an internal measure. All user-visible
 189  * units must be in seconds */
 190 static uint64_t max_downtime = 300000000;
 191
 192 uint64_t migrate_max_downtime(void)
 193 {
 194     return max_downtime;
 195 }
 196
 197 MigrationCapabilityStatusList *qmp_query_migrate_capabilities(Error **errp)
 198 {
 199     MigrationCapabilityStatusList *head = NULL;
 200     MigrationCapabilityStatusList *caps;
 201     MigrationState *s = migrate_get_current();
 202     int i;
 203
 204     caps = NULL; /* silence compiler warning */
 205     for (i = 0; i < MIGRATION_CAPABILITY_MAX; i++) {
 206         if (head == NULL) {
 207             head = g_malloc0(sizeof(*caps));
 208             caps = head;
 209         } else {
 210             caps->next = g_malloc0(sizeof(*caps));
 211             caps = caps->next;
 212         }
 213         caps->value =
 214             g_malloc(sizeof(*caps->value));
 215         caps->value->capability = i;
 216         caps->value->state = s->enabled_capabilities[i];
 217     }
 218
 219     return head;
 220 }
 221
 222 MigrationParameters *qmp_query_migrate_parameters(Error **errp)
 223 {
 224     MigrationParameters *params;
 225     MigrationState *s = migrate_get_current();
 226
 227     params = g_malloc0(sizeof(*params));
 228     params->compress_level = s->parameters[MIGRATION_PARAMETER_COMPRESS_LEVEL];
 229     params->compress_threads =
 230             s->parameters[MIGRATION_PARAMETER_COMPRESS_THREADS];
 231     params->decompress_threads =
 232             s->parameters[MIGRATION_PARAMETER_DECOMPRESS_THREADS];
 233
 234     return params;
 235 }
 236
 237 static void get_xbzrle_cache_stats(MigrationInfo *info)
 238 {
 239     if (migrate_use_xbzrle()) {
 240         info->has_xbzrle_cache = true;
 241         info->xbzrle_cache = g_malloc0(sizeof(*info->xbzrle_cache));
 242         info->xbzrle_cache->cache_size = migrate_xbzrle_cache_size();
 243         info->xbzrle_cache->bytes = xbzrle_mig_bytes_transferred();
 244         info->xbzrle_cache->pages = xbzrle_mig_pages_transferred();
 245         info->xbzrle_cache->cache_miss = xbzrle_mig_pages_cache_miss();
 246         info->xbzrle_cache->cache_miss_rate = xbzrle_mig_cache_miss_rate();
 247         info->xbzrle_cache->overflow = xbzrle_mig_pages_overflow();
 248     }
 249 }
 250
 251 MigrationInfo *qmp_query_migrate(Error **errp)
 252 {
 253     MigrationInfo *info = g_malloc0(sizeof(*info));
 254     MigrationState *s = migrate_get_current();
 255
 256     switch (s->state) {
 257     case MIGRATION_STATUS_NONE:
 258         /* no migration has happened ever */
 259         break;
 260     case MIGRATION_STATUS_SETUP:
 261         info->has_status = true;
 262         info->has_total_time = false;
 263         break;
 264     case MIGRATION_STATUS_ACTIVE:
 265     case MIGRATION_STATUS_CANCELLING:
 266         info->has_status = true;
 267         info->has_total_time = true;
 268         info->total_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME)
 269             - s->total_time;
 270         info->has_expected_downtime = true;
 271         info->expected_downtime = s->expected_downtime;
 272         info->has_setup_time = true;
 273         info->setup_time = s->setup_time;
 274
 275         info->has_ram = true;
 276         info->ram = g_malloc0(sizeof(*info->ram));
 277         info->ram->transferred = ram_bytes_transferred();
 278         info->ram->remaining = ram_bytes_remaining();
 279         info->ram->total = ram_bytes_total();
 280         info->ram->duplicate = dup_mig_pages_transferred();
 281         info->ram->skipped = skipped_mig_pages_transferred();
 282         info->ram->normal = norm_mig_pages_transferred();
 283         info->ram->normal_bytes = norm_mig_bytes_transferred();
 284         info->ram->dirty_pages_rate = s->dirty_pages_rate;
 285         info->ram->mbps = s->mbps;
 286         info->ram->dirty_sync_count = s->dirty_sync_count;
 287
 288         if (blk_mig_active()) {
 289             info->has_disk = true;
 290             info->disk = g_malloc0(sizeof(*info->disk));
 291             info->disk->transferred = blk_mig_bytes_transferred();
 292             info->disk->remaining = blk_mig_bytes_remaining();
 293             info->disk->total = blk_mig_bytes_total();
 294         }
 295
 296         get_xbzrle_cache_stats(info);
 297         break;
 298     case MIGRATION_STATUS_COMPLETED:
 299         get_xbzrle_cache_stats(info);
 300
 301         info->has_status = true;
 302         info->has_total_time = true;
 303         info->total_time = s->total_time;
 304         info->has_downtime = true;
 305         info->downtime = s->downtime;
 306         info->has_setup_time = true;
 307         info->setup_time = s->setup_time;
 308
 309         info->has_ram = true;
 310         info->ram = g_malloc0(sizeof(*info->ram));
 311         info->ram->transferred = ram_bytes_transferred();
 312         info->ram->remaining = 0;
 313         info->ram->total = ram_bytes_total();
 314         info->ram->duplicate = dup_mig_pages_transferred();
 315         info->ram->skipped = skipped_mig_pages_transferred();
 316         info->ram->normal = norm_mig_pages_transferred();
 317         info->ram->normal_bytes = norm_mig_bytes_transferred();
 318         info->ram->mbps = s->mbps;
 319         info->ram->dirty_sync_count = s->dirty_sync_count;
 320         break;
 321     case MIGRATION_STATUS_FAILED:
 322         info->has_status = true;
 323         break;
 324     case MIGRATION_STATUS_CANCELLED:
 325         info->has_status = true;
 326         break;
 327     }
 328     info->status = s->state;
 329
 330     return info;
 331 }
 332
 333 void qmp_migrate_set_capabilities(MigrationCapabilityStatusList *params,
 334                                   Error **errp)
 335 {
 336     MigrationState *s = migrate_get_current();
 337     MigrationCapabilityStatusList *cap;
 338
 339     if (s->state == MIGRATION_STATUS_ACTIVE ||
 340         s->state == MIGRATION_STATUS_SETUP) {
 341         error_setg(errp, QERR_MIGRATION_ACTIVE);
 342         return;
 343     }
 344
 345     for (cap = params; cap; cap = cap->next) {
 346         s->enabled_capabilities[cap->value->capability] = cap->value->state;
 347     }
 348 }
 349
 350 void qmp_migrate_set_parameters(bool has_compress_level,
 351                                 int64_t compress_level,
 352                                 bool has_compress_threads,
 353                                 int64_t compress_threads,
 354                                 bool has_decompress_threads,
 355                                 int64_t decompress_threads, Error **errp)
 356 {
 357     MigrationState *s = migrate_get_current();
 358
 359     if (has_compress_level && (compress_level < 0 || compress_level > 9)) {
 360         error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "compress_level",
 361                    "is invalid, it should be in the range of 0 to 9");
 362         return;
 363     }
 364     if (has_compress_threads &&
 365             (compress_threads < 1 || compress_threads > 255)) {
 366         error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
 367                    "compress_threads",
 368                    "is invalid, it should be in the range of 1 to 255");
 369         return;
 370     }
 371     if (has_decompress_threads &&
 372             (decompress_threads < 1 || decompress_threads > 255)) {
 373         error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
 374                    "decompress_threads",
 375                    "is invalid, it should be in the range of 1 to 255");
 376         return;
 377     }
 378
 379     if (has_compress_level) {
 380         s->parameters[MIGRATION_PARAMETER_COMPRESS_LEVEL] = compress_level;
 381     }
 382     if (has_compress_threads) {
 383         s->parameters[MIGRATION_PARAMETER_COMPRESS_THREADS] = compress_threads;
 384     }
 385     if (has_decompress_threads) {
 386         s->parameters[MIGRATION_PARAMETER_DECOMPRESS_THREADS] =
 387                                                     decompress_threads;
 388     }
 389 }
 390
 391 /* shared migration helpers */
 392
 393 static void migrate_set_state(MigrationState *s, int old_state, int new_state)
 394 {
 395     if (atomic_cmpxchg(&s->state, old_state, new_state) == new_state) {
 396         trace_migrate_set_state(new_state);
 397     }
 398 }
 399
 400 static void migrate_fd_cleanup(void *opaque)
 401 {
 402     MigrationState *s = opaque;
 403
 404     qemu_bh_delete(s->cleanup_bh);
 405     s->cleanup_bh = NULL;
 406
 407     if (s->file) {
 408         trace_migrate_fd_cleanup();
 409         qemu_mutex_unlock_iothread();
 410         qemu_thread_join(&s->thread);
 411         qemu_mutex_lock_iothread();
 412
 413         migrate_compress_threads_join();
 414         qemu_fclose(s->file);
 415         s->file = NULL;
 416     }
 417
 418     assert(s->state != MIGRATION_STATUS_ACTIVE);
 419
 420     if (s->state != MIGRATION_STATUS_COMPLETED) {
 421         qemu_savevm_state_cancel();
 422         if (s->state == MIGRATION_STATUS_CANCELLING) {
 423             migrate_set_state(s, MIGRATION_STATUS_CANCELLING,
 424                               MIGRATION_STATUS_CANCELLED);
 425         }
 426     }
 427
 428     notifier_list_notify(&migration_state_notifiers, s);
 429 }
 430
 431 void migrate_fd_error(MigrationState *s)
 432 {
 433     trace_migrate_fd_error();
 434     assert(s->file == NULL);
 435     s->state = MIGRATION_STATUS_FAILED;
 436     trace_migrate_set_state(MIGRATION_STATUS_FAILED);
 437     notifier_list_notify(&migration_state_notifiers, s);
 438 }
 439
 440 static void migrate_fd_cancel(MigrationState *s)
 441 {
 442     int old_state ;
 443     QEMUFile *f = migrate_get_current()->file;
 444     trace_migrate_fd_cancel();
 445
 446     do {
 447         old_state = s->state;
 448         if (old_state != MIGRATION_STATUS_SETUP &&
 449             old_state != MIGRATION_STATUS_ACTIVE) {
 450             break;
 451         }
 452         migrate_set_state(s, old_state, MIGRATION_STATUS_CANCELLING);
 453     } while (s->state != MIGRATION_STATUS_CANCELLING);
 454
 455     /*
 456      * If we're unlucky the migration code might be stuck somewhere in a
 457      * send/write while the network has failed and is waiting to timeout;
 458      * if we've got shutdown(2) available then we can force it to quit.
 459      * The outgoing qemu file gets closed in migrate_fd_cleanup that is
 460      * called in a bh, so there is no race against this cancel.
 461      */
 462     if (s->state == MIGRATION_STATUS_CANCELLING && f) {
 463         qemu_file_shutdown(f);
 464     }
 465 }
 466
 467 void add_migration_state_change_notifier(Notifier *notify)
 468 {
 469     notifier_list_add(&migration_state_notifiers, notify);
 470 }
 471
 472 void remove_migration_state_change_notifier(Notifier *notify)
 473 {
 474     notifier_remove(notify);
 475 }
 476
 477 bool migration_in_setup(MigrationState *s)
 478 {
 479     return s->state == MIGRATION_STATUS_SETUP;
 480 }
 481
 482 bool migration_has_finished(MigrationState *s)
 483 {
 484     return s->state == MIGRATION_STATUS_COMPLETED;
 485 }
 486
 487 bool migration_has_failed(MigrationState *s)
 488 {
 489     return (s->state == MIGRATION_STATUS_CANCELLED ||
 490             s->state == MIGRATION_STATUS_FAILED);
 491 }
 492
 493 static MigrationState *migrate_init(const MigrationParams *params)
 494 {
 495     MigrationState *s = migrate_get_current();
 496     int64_t bandwidth_limit = s->bandwidth_limit;
 497     bool enabled_capabilities[MIGRATION_CAPABILITY_MAX];
 498     int64_t xbzrle_cache_size = s->xbzrle_cache_size;
 499     int compress_level = s->parameters[MIGRATION_PARAMETER_COMPRESS_LEVEL];
 500     int compress_thread_count =
 501             s->parameters[MIGRATION_PARAMETER_COMPRESS_THREADS];
 502     int decompress_thread_count =
 503             s->parameters[MIGRATION_PARAMETER_DECOMPRESS_THREADS];
 504
 505     memcpy(enabled_capabilities, s->enabled_capabilities,
 506            sizeof(enabled_capabilities));
 507
 508     memset(s, 0, sizeof(*s));
 509     s->params = *params;
 510     memcpy(s->enabled_capabilities, enabled_capabilities,
 511            sizeof(enabled_capabilities));
 512     s->xbzrle_cache_size = xbzrle_cache_size;
 513
 514     s->parameters[MIGRATION_PARAMETER_COMPRESS_LEVEL] = compress_level;
 515     s->parameters[MIGRATION_PARAMETER_COMPRESS_THREADS] =
 516                compress_thread_count;
 517     s->parameters[MIGRATION_PARAMETER_DECOMPRESS_THREADS] =
 518                decompress_thread_count;
 519     s->bandwidth_limit = bandwidth_limit;
 520     s->state = MIGRATION_STATUS_SETUP;
 521     trace_migrate_set_state(MIGRATION_STATUS_SETUP);
 522
 523     s->total_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
 524     return s;
 525 }
 526
 527 static GSList *migration_blockers;
 528
 529 void migrate_add_blocker(Error *reason)
 530 {
 531     migration_blockers = g_slist_prepend(migration_blockers, reason);
 532 }
 533
 534 void migrate_del_blocker(Error *reason)
 535 {
 536     migration_blockers = g_slist_remove(migration_blockers, reason);
 537 }
 538
 539 void qmp_migrate_incoming(const char *uri, Error **errp)
 540 {
 541     Error *local_err = NULL;
 542     static bool once = true;
 543
 544     if (!deferred_incoming) {
 545         error_setg(errp, "For use with '-incoming defer'");
 546         return;
 547     }
 548     if (!once) {
 549         error_setg(errp, "The incoming migration has already been started");
 550     }
 551
 552     qemu_start_incoming_migration(uri, &local_err);
 553
 554     if (local_err) {
 555         error_propagate(errp, local_err);
 556         return;
 557     }
 558
 559     once = false;
 560 }
 561
 562 void qmp_migrate(const char *uri, bool has_blk, bool blk,
 563                  bool has_inc, bool inc, bool has_detach, bool detach,
 564                  Error **errp)
 565 {
 566     Error *local_err = NULL;
 567     MigrationState *s = migrate_get_current();
 568     MigrationParams params;
 569     const char *p;
 570
 571     params.blk = has_blk && blk;
 572     params.shared = has_inc && inc;
 573
 574     if (s->state == MIGRATION_STATUS_ACTIVE ||
 575         s->state == MIGRATION_STATUS_SETUP ||
 576         s->state == MIGRATION_STATUS_CANCELLING) {
 577         error_setg(errp, QERR_MIGRATION_ACTIVE);
 578         return;
 579     }
 580
 581     if (runstate_check(RUN_STATE_INMIGRATE)) {
 582         error_setg(errp, "Guest is waiting for an incoming migration");
 583         return;
 584     }
 585
 586     if (qemu_savevm_state_blocked(errp)) {
 587         return;
 588     }
 589
 590     if (migration_blockers) {
 591         *errp = error_copy(migration_blockers->data);
 592         return;
 593     }
 594
 595     s = migrate_init(&params);
 596
 597     if (strstart(uri, "tcp:", &p)) {
 598         tcp_start_outgoing_migration(s, p, &local_err);
 599 #ifdef CONFIG_RDMA
 600     } else if (strstart(uri, "rdma:", &p)) {
 601         rdma_start_outgoing_migration(s, p, &local_err);
 602 #endif
 603 #if !defined(WIN32)
 604     } else if (strstart(uri, "exec:", &p)) {
 605         exec_start_outgoing_migration(s, p, &local_err);
 606     } else if (strstart(uri, "unix:", &p)) {
 607         unix_start_outgoing_migration(s, p, &local_err);
 608     } else if (strstart(uri, "fd:", &p)) {
 609         fd_start_outgoing_migration(s, p, &local_err);
 610 #endif
 611     } else {
 612         error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "uri",
 613                    "a valid migration protocol");
 614         s->state = MIGRATION_STATUS_FAILED;
 615         return;
 616     }
 617
 618     if (local_err) {
 619         migrate_fd_error(s);
 620         error_propagate(errp, local_err);
 621         return;
 622     }
 623 }
 624
 625 void qmp_migrate_cancel(Error **errp)
 626 {
 627     migrate_fd_cancel(migrate_get_current());
 628 }
 629
 630 void qmp_migrate_set_cache_size(int64_t value, Error **errp)
 631 {
 632     MigrationState *s = migrate_get_current();
 633     int64_t new_size;
 634
 635     /* Check for truncation */
 636     if (value != (size_t)value) {
 637         error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cache size",
 638                    "exceeding address space");
 639         return;
 640     }
 641
 642     /* Cache should not be larger than guest ram size */
 643     if (value > ram_bytes_total()) {
 644         error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cache size",
 645                    "exceeds guest ram size ");
 646         return;
 647     }
 648
 649     new_size = xbzrle_cache_resize(value);
 650     if (new_size < 0) {
 651         error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cache size",
 652                    "is smaller than page size");
 653         return;
 654     }
 655
 656     s->xbzrle_cache_size = new_size;
 657 }
 658
 659 int64_t qmp_query_migrate_cache_size(Error **errp)
 660 {
 661     return migrate_xbzrle_cache_size();
 662 }
 663
 664 void qmp_migrate_set_speed(int64_t value, Error **errp)
 665 {
 666     MigrationState *s;
 667
 668     if (value < 0) {
 669         value = 0;
 670     }
 671     if (value > SIZE_MAX) {
 672         value = SIZE_MAX;
 673     }
 674
 675     s = migrate_get_current();
 676     s->bandwidth_limit = value;
 677     if (s->file) {
 678         qemu_file_set_rate_limit(s->file, s->bandwidth_limit / XFER_LIMIT_RATIO);
 679     }
 680 }
 681
 682 void qmp_migrate_set_downtime(double value, Error **errp)
 683 {
 684     value *= 1e9;
 685     value = MAX(0, MIN(UINT64_MAX, value));
 686     max_downtime = (uint64_t)value;
 687 }
 688
 689 bool migrate_auto_converge(void)
 690 {
 691     MigrationState *s;
 692
 693     s = migrate_get_current();
 694
 695     return s->enabled_capabilities[MIGRATION_CAPABILITY_AUTO_CONVERGE];
 696 }
 697
 698 bool migrate_zero_blocks(void)
 699 {
 700     MigrationState *s;
 701
 702     s = migrate_get_current();
 703
 704     return s->enabled_capabilities[MIGRATION_CAPABILITY_ZERO_BLOCKS];
 705 }
 706
 707 bool migrate_use_compression(void)
 708 {
 709     MigrationState *s;
 710
 711     s = migrate_get_current();
 712
 713     return s->enabled_capabilities[MIGRATION_CAPABILITY_COMPRESS];
 714 }
 715
 716 int migrate_compress_level(void)
 717 {
 718     MigrationState *s;
 719
 720     s = migrate_get_current();
 721
 722     return s->parameters[MIGRATION_PARAMETER_COMPRESS_LEVEL];
 723 }
 724
 725 int migrate_compress_threads(void)
 726 {
 727     MigrationState *s;
 728
 729     s = migrate_get_current();
 730
 731     return s->parameters[MIGRATION_PARAMETER_COMPRESS_THREADS];
 732 }
 733
 734 int migrate_decompress_threads(void)
 735 {
 736     MigrationState *s;
 737
 738     s = migrate_get_current();
 739
 740     return s->parameters[MIGRATION_PARAMETER_DECOMPRESS_THREADS];
 741 }
 742
 743 int migrate_use_xbzrle(void)
 744 {
 745     MigrationState *s;
 746
 747     s = migrate_get_current();
 748
 749     return s->enabled_capabilities[MIGRATION_CAPABILITY_XBZRLE];
 750 }
 751
 752 int64_t migrate_xbzrle_cache_size(void)
 753 {
 754     MigrationState *s;
 755
 756     s = migrate_get_current();
 757
 758     return s->xbzrle_cache_size;
 759 }
 760
 761 /* migration thread support */
 762
 763 static void *migration_thread(void *opaque)
 764 {
 765     MigrationState *s = opaque;
 766     int64_t initial_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
 767     int64_t setup_start = qemu_clock_get_ms(QEMU_CLOCK_HOST);
 768     int64_t initial_bytes = 0;
 769     int64_t max_size = 0;
 770     int64_t start_time = initial_time;
 771     bool old_vm_running = false;
 772
 773     qemu_savevm_state_header(s->file);
 774     qemu_savevm_state_begin(s->file, &s->params);
 775
 776     s->setup_time = qemu_clock_get_ms(QEMU_CLOCK_HOST) - setup_start;
 777     migrate_set_state(s, MIGRATION_STATUS_SETUP, MIGRATION_STATUS_ACTIVE);
 778
 779     while (s->state == MIGRATION_STATUS_ACTIVE) {
 780         int64_t current_time;
 781         uint64_t pending_size;
 782
 783         if (!qemu_file_rate_limit(s->file)) {
 784             pending_size = qemu_savevm_state_pending(s->file, max_size);
 785             trace_migrate_pending(pending_size, max_size);
 786             if (pending_size && pending_size >= max_size) {
 787                 qemu_savevm_state_iterate(s->file);
 788             } else {
 789                 int ret;
 790
 791                 qemu_mutex_lock_iothread();
 792                 start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
 793                 qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER);
 794                 old_vm_running = runstate_is_running();
 795
 796                 ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
 797                 if (ret >= 0) {
 798                     qemu_file_set_rate_limit(s->file, INT64_MAX);
 799                     qemu_savevm_state_complete(s->file);
 800                 }
 801                 qemu_mutex_unlock_iothread();
 802
 803                 if (ret < 0) {
 804                     migrate_set_state(s, MIGRATION_STATUS_ACTIVE,
 805                                       MIGRATION_STATUS_FAILED);
 806                     break;
 807                 }
 808
 809                 if (!qemu_file_get_error(s->file)) {
 810                     migrate_set_state(s, MIGRATION_STATUS_ACTIVE,
 811                                       MIGRATION_STATUS_COMPLETED);
 812                     break;
 813                 }
 814             }
 815         }
 816
 817         if (qemu_file_get_error(s->file)) {
 818             migrate_set_state(s, MIGRATION_STATUS_ACTIVE,
 819                               MIGRATION_STATUS_FAILED);
 820             break;
 821         }
 822         current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
 823         if (current_time >= initial_time + BUFFER_DELAY) {
 824             uint64_t transferred_bytes = qemu_ftell(s->file) - initial_bytes;
 825             uint64_t time_spent = current_time - initial_time;
 826             double bandwidth = transferred_bytes / time_spent;
 827             max_size = bandwidth * migrate_max_downtime() / 1000000;
 828
 829             s->mbps = time_spent ? (((double) transferred_bytes * 8.0) /
 830                     ((double) time_spent / 1000.0)) / 1000.0 / 1000.0 : -1;
 831
 832             trace_migrate_transferred(transferred_bytes, time_spent,
 833                                       bandwidth, max_size);
 834             /* if we haven't sent anything, we don't want to recalculate
 835                10000 is a small enough number for our purposes */
 836             if (s->dirty_bytes_rate && transferred_bytes > 10000) {
 837                 s->expected_downtime = s->dirty_bytes_rate / bandwidth;
 838             }
 839
 840             qemu_file_reset_rate_limit(s->file);
 841             initial_time = current_time;
 842             initial_bytes = qemu_ftell(s->file);
 843         }
 844         if (qemu_file_rate_limit(s->file)) {
 845             /* usleep expects microseconds */
 846             g_usleep((initial_time + BUFFER_DELAY - current_time)*1000);
 847         }
 848     }
 849
 850     qemu_mutex_lock_iothread();
 851     if (s->state == MIGRATION_STATUS_COMPLETED) {
 852         int64_t end_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
 853         uint64_t transferred_bytes = qemu_ftell(s->file);
 854         s->total_time = end_time - s->total_time;
 855         s->downtime = end_time - start_time;
 856         if (s->total_time) {
 857             s->mbps = (((double) transferred_bytes * 8.0) /
 858                        ((double) s->total_time)) / 1000;
 859         }
 860         runstate_set(RUN_STATE_POSTMIGRATE);
 861     } else {
 862         if (old_vm_running) {
 863             vm_start();
 864         }
 865     }
 866     qemu_bh_schedule(s->cleanup_bh);
 867     qemu_mutex_unlock_iothread();
 868
 869     return NULL;
 870 }
 871
 872 void migrate_fd_connect(MigrationState *s)
 873 {
 874     /* This is a best 1st approximation. ns to ms */
 875     s->expected_downtime = max_downtime/1000000;
 876     s->cleanup_bh = qemu_bh_new(migrate_fd_cleanup, s);
 877
 878     qemu_file_set_rate_limit(s->file,
 879                              s->bandwidth_limit / XFER_LIMIT_RATIO);
 880
 881     /* Notify before starting migration thread */
 882     notifier_list_notify(&migration_state_notifiers, s);
 883
 884     migrate_compress_threads_create();
 885     qemu_thread_create(&s->thread, "migration", migration_thread, s,
 886                        QEMU_THREAD_JOINABLE);
 887 }