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/osdep.h" 17 #include "qemu-common.h" 18 #include "qemu/error-report.h" 19 #include "qemu/main-loop.h" 20 #include "migration/migration.h" 21 #include "migration/qemu-file.h" 22 #include "sysemu/sysemu.h" 23 #include "block/block.h" 24 #include "qapi/qmp/qerror.h" 25 #include "qapi/util.h" 26 #include "qemu/sockets.h" 27 #include "qemu/rcu.h" 28 #include "migration/block.h" 29 #include "migration/postcopy-ram.h" 30 #include "qemu/thread.h" 31 #include "qmp-commands.h" 32 #include "trace.h" 33 #include "qapi-event.h" 34 #include "qom/cpu.h" 35 #include "exec/memory.h" 36 #include "exec/address-spaces.h" 37 38 #define MAX_THROTTLE (32 << 20) /* Migration transfer speed throttling */ 39 40 /* Amount of time to allocate to each "chunk" of bandwidth-throttled 41 * data. */ 42 #define BUFFER_DELAY 100 43 #define XFER_LIMIT_RATIO (1000 / BUFFER_DELAY) 44 45 /* Default compression thread count */ 46 #define DEFAULT_MIGRATE_COMPRESS_THREAD_COUNT 8 47 /* Default decompression thread count, usually decompression is at 48 * least 4 times as fast as compression.*/ 49 #define DEFAULT_MIGRATE_DECOMPRESS_THREAD_COUNT 2 50 /*0: means nocompress, 1: best speed, ... 9: best compress ratio */ 51 #define DEFAULT_MIGRATE_COMPRESS_LEVEL 1 52 /* Define default autoconverge cpu throttle migration parameters */ 53 #define DEFAULT_MIGRATE_X_CPU_THROTTLE_INITIAL 20 54 #define DEFAULT_MIGRATE_X_CPU_THROTTLE_INCREMENT 10 55 56 /* Migration XBZRLE default cache size */ 57 #define DEFAULT_MIGRATE_CACHE_SIZE (64 * 1024 * 1024) 58 59 static NotifierList migration_state_notifiers = 60 NOTIFIER_LIST_INITIALIZER(migration_state_notifiers); 61 62 static bool deferred_incoming; 63 64 /* 65 * Current state of incoming postcopy; note this is not part of 66 * MigrationIncomingState since it's state is used during cleanup 67 * at the end as MIS is being freed. 68 */ 69 static PostcopyState incoming_postcopy_state; 70 71 /* When we add fault tolerance, we could have several 72 migrations at once. For now we don't need to add 73 dynamic creation of migration */ 74 75 /* For outgoing */ 76 MigrationState *migrate_get_current(void) 77 { 78 static bool once; 79 static MigrationState current_migration = { 80 .state = MIGRATION_STATUS_NONE, 81 .bandwidth_limit = MAX_THROTTLE, 82 .xbzrle_cache_size = DEFAULT_MIGRATE_CACHE_SIZE, 83 .mbps = -1, 84 .parameters[MIGRATION_PARAMETER_COMPRESS_LEVEL] = 85 DEFAULT_MIGRATE_COMPRESS_LEVEL, 86 .parameters[MIGRATION_PARAMETER_COMPRESS_THREADS] = 87 DEFAULT_MIGRATE_COMPRESS_THREAD_COUNT, 88 .parameters[MIGRATION_PARAMETER_DECOMPRESS_THREADS] = 89 DEFAULT_MIGRATE_DECOMPRESS_THREAD_COUNT, 90 .parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INITIAL] = 91 DEFAULT_MIGRATE_X_CPU_THROTTLE_INITIAL, 92 .parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INCREMENT] = 93 DEFAULT_MIGRATE_X_CPU_THROTTLE_INCREMENT, 94 }; 95 96 if (!once) { 97 qemu_mutex_init(¤t_migration.src_page_req_mutex); 98 once = true; 99 } 100 return ¤t_migration; 101 } 102 103 /* For incoming */ 104 static MigrationIncomingState *mis_current; 105 106 MigrationIncomingState *migration_incoming_get_current(void) 107 { 108 return mis_current; 109 } 110 111 MigrationIncomingState *migration_incoming_state_new(QEMUFile* f) 112 { 113 mis_current = g_new0(MigrationIncomingState, 1); 114 mis_current->from_src_file = f; 115 mis_current->state = MIGRATION_STATUS_NONE; 116 QLIST_INIT(&mis_current->loadvm_handlers); 117 qemu_mutex_init(&mis_current->rp_mutex); 118 qemu_event_init(&mis_current->main_thread_load_event, false); 119 120 return mis_current; 121 } 122 123 void migration_incoming_state_destroy(void) 124 { 125 qemu_event_destroy(&mis_current->main_thread_load_event); 126 loadvm_free_handlers(mis_current); 127 g_free(mis_current); 128 mis_current = NULL; 129 } 130 131 132 typedef struct { 133 bool optional; 134 uint32_t size; 135 uint8_t runstate[100]; 136 RunState state; 137 bool received; 138 } GlobalState; 139 140 static GlobalState global_state; 141 142 int global_state_store(void) 143 { 144 if (!runstate_store((char *)global_state.runstate, 145 sizeof(global_state.runstate))) { 146 error_report("runstate name too big: %s", global_state.runstate); 147 trace_migrate_state_too_big(); 148 return -EINVAL; 149 } 150 return 0; 151 } 152 153 void global_state_store_running(void) 154 { 155 const char *state = RunState_lookup[RUN_STATE_RUNNING]; 156 strncpy((char *)global_state.runstate, 157 state, sizeof(global_state.runstate)); 158 } 159 160 static bool global_state_received(void) 161 { 162 return global_state.received; 163 } 164 165 static RunState global_state_get_runstate(void) 166 { 167 return global_state.state; 168 } 169 170 void global_state_set_optional(void) 171 { 172 global_state.optional = true; 173 } 174 175 static bool global_state_needed(void *opaque) 176 { 177 GlobalState *s = opaque; 178 char *runstate = (char *)s->runstate; 179 180 /* If it is not optional, it is mandatory */ 181 182 if (s->optional == false) { 183 return true; 184 } 185 186 /* If state is running or paused, it is not needed */ 187 188 if (strcmp(runstate, "running") == 0 || 189 strcmp(runstate, "paused") == 0) { 190 return false; 191 } 192 193 /* for any other state it is needed */ 194 return true; 195 } 196 197 static int global_state_post_load(void *opaque, int version_id) 198 { 199 GlobalState *s = opaque; 200 Error *local_err = NULL; 201 int r; 202 char *runstate = (char *)s->runstate; 203 204 s->received = true; 205 trace_migrate_global_state_post_load(runstate); 206 207 r = qapi_enum_parse(RunState_lookup, runstate, RUN_STATE__MAX, 208 -1, &local_err); 209 210 if (r == -1) { 211 if (local_err) { 212 error_report_err(local_err); 213 } 214 return -EINVAL; 215 } 216 s->state = r; 217 218 return 0; 219 } 220 221 static void global_state_pre_save(void *opaque) 222 { 223 GlobalState *s = opaque; 224 225 trace_migrate_global_state_pre_save((char *)s->runstate); 226 s->size = strlen((char *)s->runstate) + 1; 227 } 228 229 static const VMStateDescription vmstate_globalstate = { 230 .name = "globalstate", 231 .version_id = 1, 232 .minimum_version_id = 1, 233 .post_load = global_state_post_load, 234 .pre_save = global_state_pre_save, 235 .needed = global_state_needed, 236 .fields = (VMStateField[]) { 237 VMSTATE_UINT32(size, GlobalState), 238 VMSTATE_BUFFER(runstate, GlobalState), 239 VMSTATE_END_OF_LIST() 240 }, 241 }; 242 243 void register_global_state(void) 244 { 245 /* We would use it independently that we receive it */ 246 strcpy((char *)&global_state.runstate, ""); 247 global_state.received = false; 248 vmstate_register(NULL, 0, &vmstate_globalstate, &global_state); 249 } 250 251 static void migrate_generate_event(int new_state) 252 { 253 if (migrate_use_events()) { 254 qapi_event_send_migration(new_state, &error_abort); 255 } 256 } 257 258 /* 259 * Called on -incoming with a defer: uri. 260 * The migration can be started later after any parameters have been 261 * changed. 262 */ 263 static void deferred_incoming_migration(Error **errp) 264 { 265 if (deferred_incoming) { 266 error_setg(errp, "Incoming migration already deferred"); 267 } 268 deferred_incoming = true; 269 } 270 271 /* Request a range of pages from the source VM at the given 272 * start address. 273 * rbname: Name of the RAMBlock to request the page in, if NULL it's the same 274 * as the last request (a name must have been given previously) 275 * Start: Address offset within the RB 276 * Len: Length in bytes required - must be a multiple of pagesize 277 */ 278 void migrate_send_rp_req_pages(MigrationIncomingState *mis, const char *rbname, 279 ram_addr_t start, size_t len) 280 { 281 uint8_t bufc[12 + 1 + 255]; /* start (8), len (4), rbname upto 256 */ 282 size_t msglen = 12; /* start + len */ 283 284 *(uint64_t *)bufc = cpu_to_be64((uint64_t)start); 285 *(uint32_t *)(bufc + 8) = cpu_to_be32((uint32_t)len); 286 287 if (rbname) { 288 int rbname_len = strlen(rbname); 289 assert(rbname_len < 256); 290 291 bufc[msglen++] = rbname_len; 292 memcpy(bufc + msglen, rbname, rbname_len); 293 msglen += rbname_len; 294 migrate_send_rp_message(mis, MIG_RP_MSG_REQ_PAGES_ID, msglen, bufc); 295 } else { 296 migrate_send_rp_message(mis, MIG_RP_MSG_REQ_PAGES, msglen, bufc); 297 } 298 } 299 300 void qemu_start_incoming_migration(const char *uri, Error **errp) 301 { 302 const char *p; 303 304 qapi_event_send_migration(MIGRATION_STATUS_SETUP, &error_abort); 305 if (!strcmp(uri, "defer")) { 306 deferred_incoming_migration(errp); 307 } else if (strstart(uri, "tcp:", &p)) { 308 tcp_start_incoming_migration(p, errp); 309 #ifdef CONFIG_RDMA 310 } else if (strstart(uri, "rdma:", &p)) { 311 rdma_start_incoming_migration(p, errp); 312 #endif 313 #if !defined(WIN32) 314 } else if (strstart(uri, "exec:", &p)) { 315 exec_start_incoming_migration(p, errp); 316 } else if (strstart(uri, "unix:", &p)) { 317 unix_start_incoming_migration(p, errp); 318 } else if (strstart(uri, "fd:", &p)) { 319 fd_start_incoming_migration(p, errp); 320 #endif 321 } else { 322 error_setg(errp, "unknown migration protocol: %s", uri); 323 } 324 } 325 326 static void process_incoming_migration_bh(void *opaque) 327 { 328 Error *local_err = NULL; 329 MigrationIncomingState *mis = opaque; 330 331 /* Make sure all file formats flush their mutable metadata */ 332 bdrv_invalidate_cache_all(&local_err); 333 if (local_err) { 334 migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE, 335 MIGRATION_STATUS_FAILED); 336 error_report_err(local_err); 337 migrate_decompress_threads_join(); 338 exit(EXIT_FAILURE); 339 } 340 341 /* 342 * This must happen after all error conditions are dealt with and 343 * we're sure the VM is going to be running on this host. 344 */ 345 qemu_announce_self(); 346 347 /* If global state section was not received or we are in running 348 state, we need to obey autostart. Any other state is set with 349 runstate_set. */ 350 351 if (!global_state_received() || 352 global_state_get_runstate() == RUN_STATE_RUNNING) { 353 if (autostart) { 354 vm_start(); 355 } else { 356 runstate_set(RUN_STATE_PAUSED); 357 } 358 } else { 359 runstate_set(global_state_get_runstate()); 360 } 361 migrate_decompress_threads_join(); 362 /* 363 * This must happen after any state changes since as soon as an external 364 * observer sees this event they might start to prod at the VM assuming 365 * it's ready to use. 366 */ 367 migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE, 368 MIGRATION_STATUS_COMPLETED); 369 qemu_bh_delete(mis->bh); 370 migration_incoming_state_destroy(); 371 } 372 373 static void process_incoming_migration_co(void *opaque) 374 { 375 QEMUFile *f = opaque; 376 MigrationIncomingState *mis; 377 PostcopyState ps; 378 int ret; 379 380 mis = migration_incoming_state_new(f); 381 postcopy_state_set(POSTCOPY_INCOMING_NONE); 382 migrate_set_state(&mis->state, MIGRATION_STATUS_NONE, 383 MIGRATION_STATUS_ACTIVE); 384 ret = qemu_loadvm_state(f); 385 386 ps = postcopy_state_get(); 387 trace_process_incoming_migration_co_end(ret, ps); 388 if (ps != POSTCOPY_INCOMING_NONE) { 389 if (ps == POSTCOPY_INCOMING_ADVISE) { 390 /* 391 * Where a migration had postcopy enabled (and thus went to advise) 392 * but managed to complete within the precopy period, we can use 393 * the normal exit. 394 */ 395 postcopy_ram_incoming_cleanup(mis); 396 } else if (ret >= 0) { 397 /* 398 * Postcopy was started, cleanup should happen at the end of the 399 * postcopy thread. 400 */ 401 trace_process_incoming_migration_co_postcopy_end_main(); 402 return; 403 } 404 /* Else if something went wrong then just fall out of the normal exit */ 405 } 406 407 qemu_fclose(f); 408 free_xbzrle_decoded_buf(); 409 410 if (ret < 0) { 411 migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE, 412 MIGRATION_STATUS_FAILED); 413 error_report("load of migration failed: %s", strerror(-ret)); 414 migrate_decompress_threads_join(); 415 exit(EXIT_FAILURE); 416 } 417 418 mis->bh = qemu_bh_new(process_incoming_migration_bh, mis); 419 qemu_bh_schedule(mis->bh); 420 } 421 422 void process_incoming_migration(QEMUFile *f) 423 { 424 Coroutine *co = qemu_coroutine_create(process_incoming_migration_co); 425 int fd = qemu_get_fd(f); 426 427 assert(fd != -1); 428 migrate_decompress_threads_create(); 429 qemu_set_nonblock(fd); 430 qemu_coroutine_enter(co, f); 431 } 432 433 /* 434 * Send a message on the return channel back to the source 435 * of the migration. 436 */ 437 void migrate_send_rp_message(MigrationIncomingState *mis, 438 enum mig_rp_message_type message_type, 439 uint16_t len, void *data) 440 { 441 trace_migrate_send_rp_message((int)message_type, len); 442 qemu_mutex_lock(&mis->rp_mutex); 443 qemu_put_be16(mis->to_src_file, (unsigned int)message_type); 444 qemu_put_be16(mis->to_src_file, len); 445 qemu_put_buffer(mis->to_src_file, data, len); 446 qemu_fflush(mis->to_src_file); 447 qemu_mutex_unlock(&mis->rp_mutex); 448 } 449 450 /* 451 * Send a 'SHUT' message on the return channel with the given value 452 * to indicate that we've finished with the RP. Non-0 value indicates 453 * error. 454 */ 455 void migrate_send_rp_shut(MigrationIncomingState *mis, 456 uint32_t value) 457 { 458 uint32_t buf; 459 460 buf = cpu_to_be32(value); 461 migrate_send_rp_message(mis, MIG_RP_MSG_SHUT, sizeof(buf), &buf); 462 } 463 464 /* 465 * Send a 'PONG' message on the return channel with the given value 466 * (normally in response to a 'PING') 467 */ 468 void migrate_send_rp_pong(MigrationIncomingState *mis, 469 uint32_t value) 470 { 471 uint32_t buf; 472 473 buf = cpu_to_be32(value); 474 migrate_send_rp_message(mis, MIG_RP_MSG_PONG, sizeof(buf), &buf); 475 } 476 477 /* amount of nanoseconds we are willing to wait for migration to be down. 478 * the choice of nanoseconds is because it is the maximum resolution that 479 * get_clock() can achieve. It is an internal measure. All user-visible 480 * units must be in seconds */ 481 static uint64_t max_downtime = 300000000; 482 483 uint64_t migrate_max_downtime(void) 484 { 485 return max_downtime; 486 } 487 488 MigrationCapabilityStatusList *qmp_query_migrate_capabilities(Error **errp) 489 { 490 MigrationCapabilityStatusList *head = NULL; 491 MigrationCapabilityStatusList *caps; 492 MigrationState *s = migrate_get_current(); 493 int i; 494 495 caps = NULL; /* silence compiler warning */ 496 for (i = 0; i < MIGRATION_CAPABILITY__MAX; i++) { 497 if (head == NULL) { 498 head = g_malloc0(sizeof(*caps)); 499 caps = head; 500 } else { 501 caps->next = g_malloc0(sizeof(*caps)); 502 caps = caps->next; 503 } 504 caps->value = 505 g_malloc(sizeof(*caps->value)); 506 caps->value->capability = i; 507 caps->value->state = s->enabled_capabilities[i]; 508 } 509 510 return head; 511 } 512 513 MigrationParameters *qmp_query_migrate_parameters(Error **errp) 514 { 515 MigrationParameters *params; 516 MigrationState *s = migrate_get_current(); 517 518 params = g_malloc0(sizeof(*params)); 519 params->compress_level = s->parameters[MIGRATION_PARAMETER_COMPRESS_LEVEL]; 520 params->compress_threads = 521 s->parameters[MIGRATION_PARAMETER_COMPRESS_THREADS]; 522 params->decompress_threads = 523 s->parameters[MIGRATION_PARAMETER_DECOMPRESS_THREADS]; 524 params->x_cpu_throttle_initial = 525 s->parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INITIAL]; 526 params->x_cpu_throttle_increment = 527 s->parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INCREMENT]; 528 529 return params; 530 } 531 532 /* 533 * Return true if we're already in the middle of a migration 534 * (i.e. any of the active or setup states) 535 */ 536 static bool migration_is_setup_or_active(int state) 537 { 538 switch (state) { 539 case MIGRATION_STATUS_ACTIVE: 540 case MIGRATION_STATUS_POSTCOPY_ACTIVE: 541 case MIGRATION_STATUS_SETUP: 542 return true; 543 544 default: 545 return false; 546 547 } 548 } 549 550 static void get_xbzrle_cache_stats(MigrationInfo *info) 551 { 552 if (migrate_use_xbzrle()) { 553 info->has_xbzrle_cache = true; 554 info->xbzrle_cache = g_malloc0(sizeof(*info->xbzrle_cache)); 555 info->xbzrle_cache->cache_size = migrate_xbzrle_cache_size(); 556 info->xbzrle_cache->bytes = xbzrle_mig_bytes_transferred(); 557 info->xbzrle_cache->pages = xbzrle_mig_pages_transferred(); 558 info->xbzrle_cache->cache_miss = xbzrle_mig_pages_cache_miss(); 559 info->xbzrle_cache->cache_miss_rate = xbzrle_mig_cache_miss_rate(); 560 info->xbzrle_cache->overflow = xbzrle_mig_pages_overflow(); 561 } 562 } 563 564 MigrationInfo *qmp_query_migrate(Error **errp) 565 { 566 MigrationInfo *info = g_malloc0(sizeof(*info)); 567 MigrationState *s = migrate_get_current(); 568 569 switch (s->state) { 570 case MIGRATION_STATUS_NONE: 571 /* no migration has happened ever */ 572 break; 573 case MIGRATION_STATUS_SETUP: 574 info->has_status = true; 575 info->has_total_time = false; 576 break; 577 case MIGRATION_STATUS_ACTIVE: 578 case MIGRATION_STATUS_CANCELLING: 579 info->has_status = true; 580 info->has_total_time = true; 581 info->total_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) 582 - s->total_time; 583 info->has_expected_downtime = true; 584 info->expected_downtime = s->expected_downtime; 585 info->has_setup_time = true; 586 info->setup_time = s->setup_time; 587 588 info->has_ram = true; 589 info->ram = g_malloc0(sizeof(*info->ram)); 590 info->ram->transferred = ram_bytes_transferred(); 591 info->ram->remaining = ram_bytes_remaining(); 592 info->ram->total = ram_bytes_total(); 593 info->ram->duplicate = dup_mig_pages_transferred(); 594 info->ram->skipped = skipped_mig_pages_transferred(); 595 info->ram->normal = norm_mig_pages_transferred(); 596 info->ram->normal_bytes = norm_mig_bytes_transferred(); 597 info->ram->dirty_pages_rate = s->dirty_pages_rate; 598 info->ram->mbps = s->mbps; 599 info->ram->dirty_sync_count = s->dirty_sync_count; 600 601 if (blk_mig_active()) { 602 info->has_disk = true; 603 info->disk = g_malloc0(sizeof(*info->disk)); 604 info->disk->transferred = blk_mig_bytes_transferred(); 605 info->disk->remaining = blk_mig_bytes_remaining(); 606 info->disk->total = blk_mig_bytes_total(); 607 } 608 609 if (cpu_throttle_active()) { 610 info->has_x_cpu_throttle_percentage = true; 611 info->x_cpu_throttle_percentage = cpu_throttle_get_percentage(); 612 } 613 614 get_xbzrle_cache_stats(info); 615 break; 616 case MIGRATION_STATUS_POSTCOPY_ACTIVE: 617 /* Mostly the same as active; TODO add some postcopy stats */ 618 info->has_status = true; 619 info->has_total_time = true; 620 info->total_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) 621 - s->total_time; 622 info->has_expected_downtime = true; 623 info->expected_downtime = s->expected_downtime; 624 info->has_setup_time = true; 625 info->setup_time = s->setup_time; 626 627 info->has_ram = true; 628 info->ram = g_malloc0(sizeof(*info->ram)); 629 info->ram->transferred = ram_bytes_transferred(); 630 info->ram->remaining = ram_bytes_remaining(); 631 info->ram->total = ram_bytes_total(); 632 info->ram->duplicate = dup_mig_pages_transferred(); 633 info->ram->skipped = skipped_mig_pages_transferred(); 634 info->ram->normal = norm_mig_pages_transferred(); 635 info->ram->normal_bytes = norm_mig_bytes_transferred(); 636 info->ram->dirty_pages_rate = s->dirty_pages_rate; 637 info->ram->mbps = s->mbps; 638 info->ram->dirty_sync_count = s->dirty_sync_count; 639 640 if (blk_mig_active()) { 641 info->has_disk = true; 642 info->disk = g_malloc0(sizeof(*info->disk)); 643 info->disk->transferred = blk_mig_bytes_transferred(); 644 info->disk->remaining = blk_mig_bytes_remaining(); 645 info->disk->total = blk_mig_bytes_total(); 646 } 647 648 get_xbzrle_cache_stats(info); 649 break; 650 case MIGRATION_STATUS_COMPLETED: 651 get_xbzrle_cache_stats(info); 652 653 info->has_status = true; 654 info->has_total_time = true; 655 info->total_time = s->total_time; 656 info->has_downtime = true; 657 info->downtime = s->downtime; 658 info->has_setup_time = true; 659 info->setup_time = s->setup_time; 660 661 info->has_ram = true; 662 info->ram = g_malloc0(sizeof(*info->ram)); 663 info->ram->transferred = ram_bytes_transferred(); 664 info->ram->remaining = 0; 665 info->ram->total = ram_bytes_total(); 666 info->ram->duplicate = dup_mig_pages_transferred(); 667 info->ram->skipped = skipped_mig_pages_transferred(); 668 info->ram->normal = norm_mig_pages_transferred(); 669 info->ram->normal_bytes = norm_mig_bytes_transferred(); 670 info->ram->mbps = s->mbps; 671 info->ram->dirty_sync_count = s->dirty_sync_count; 672 break; 673 case MIGRATION_STATUS_FAILED: 674 info->has_status = true; 675 break; 676 case MIGRATION_STATUS_CANCELLED: 677 info->has_status = true; 678 break; 679 } 680 info->status = s->state; 681 682 return info; 683 } 684 685 void qmp_migrate_set_capabilities(MigrationCapabilityStatusList *params, 686 Error **errp) 687 { 688 MigrationState *s = migrate_get_current(); 689 MigrationCapabilityStatusList *cap; 690 691 if (migration_is_setup_or_active(s->state)) { 692 error_setg(errp, QERR_MIGRATION_ACTIVE); 693 return; 694 } 695 696 for (cap = params; cap; cap = cap->next) { 697 s->enabled_capabilities[cap->value->capability] = cap->value->state; 698 } 699 700 if (migrate_postcopy_ram()) { 701 if (migrate_use_compression()) { 702 /* The decompression threads asynchronously write into RAM 703 * rather than use the atomic copies needed to avoid 704 * userfaulting. It should be possible to fix the decompression 705 * threads for compatibility in future. 706 */ 707 error_report("Postcopy is not currently compatible with " 708 "compression"); 709 s->enabled_capabilities[MIGRATION_CAPABILITY_POSTCOPY_RAM] = 710 false; 711 } 712 } 713 } 714 715 void qmp_migrate_set_parameters(bool has_compress_level, 716 int64_t compress_level, 717 bool has_compress_threads, 718 int64_t compress_threads, 719 bool has_decompress_threads, 720 int64_t decompress_threads, 721 bool has_x_cpu_throttle_initial, 722 int64_t x_cpu_throttle_initial, 723 bool has_x_cpu_throttle_increment, 724 int64_t x_cpu_throttle_increment, Error **errp) 725 { 726 MigrationState *s = migrate_get_current(); 727 728 if (has_compress_level && (compress_level < 0 || compress_level > 9)) { 729 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "compress_level", 730 "is invalid, it should be in the range of 0 to 9"); 731 return; 732 } 733 if (has_compress_threads && 734 (compress_threads < 1 || compress_threads > 255)) { 735 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, 736 "compress_threads", 737 "is invalid, it should be in the range of 1 to 255"); 738 return; 739 } 740 if (has_decompress_threads && 741 (decompress_threads < 1 || decompress_threads > 255)) { 742 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, 743 "decompress_threads", 744 "is invalid, it should be in the range of 1 to 255"); 745 return; 746 } 747 if (has_x_cpu_throttle_initial && 748 (x_cpu_throttle_initial < 1 || x_cpu_throttle_initial > 99)) { 749 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, 750 "x_cpu_throttle_initial", 751 "an integer in the range of 1 to 99"); 752 } 753 if (has_x_cpu_throttle_increment && 754 (x_cpu_throttle_increment < 1 || x_cpu_throttle_increment > 99)) { 755 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, 756 "x_cpu_throttle_increment", 757 "an integer in the range of 1 to 99"); 758 } 759 760 if (has_compress_level) { 761 s->parameters[MIGRATION_PARAMETER_COMPRESS_LEVEL] = compress_level; 762 } 763 if (has_compress_threads) { 764 s->parameters[MIGRATION_PARAMETER_COMPRESS_THREADS] = compress_threads; 765 } 766 if (has_decompress_threads) { 767 s->parameters[MIGRATION_PARAMETER_DECOMPRESS_THREADS] = 768 decompress_threads; 769 } 770 if (has_x_cpu_throttle_initial) { 771 s->parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INITIAL] = 772 x_cpu_throttle_initial; 773 } 774 775 if (has_x_cpu_throttle_increment) { 776 s->parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INCREMENT] = 777 x_cpu_throttle_increment; 778 } 779 } 780 781 void qmp_migrate_start_postcopy(Error **errp) 782 { 783 MigrationState *s = migrate_get_current(); 784 785 if (!migrate_postcopy_ram()) { 786 error_setg(errp, "Enable postcopy with migrate_set_capability before" 787 " the start of migration"); 788 return; 789 } 790 791 if (s->state == MIGRATION_STATUS_NONE) { 792 error_setg(errp, "Postcopy must be started after migration has been" 793 " started"); 794 return; 795 } 796 /* 797 * we don't error if migration has finished since that would be racy 798 * with issuing this command. 799 */ 800 atomic_set(&s->start_postcopy, true); 801 } 802 803 /* shared migration helpers */ 804 805 void migrate_set_state(int *state, int old_state, int new_state) 806 { 807 if (atomic_cmpxchg(state, old_state, new_state) == old_state) { 808 trace_migrate_set_state(new_state); 809 migrate_generate_event(new_state); 810 } 811 } 812 813 static void migrate_fd_cleanup(void *opaque) 814 { 815 MigrationState *s = opaque; 816 817 qemu_bh_delete(s->cleanup_bh); 818 s->cleanup_bh = NULL; 819 820 flush_page_queue(s); 821 822 if (s->to_dst_file) { 823 trace_migrate_fd_cleanup(); 824 qemu_mutex_unlock_iothread(); 825 if (s->migration_thread_running) { 826 qemu_thread_join(&s->thread); 827 s->migration_thread_running = false; 828 } 829 qemu_mutex_lock_iothread(); 830 831 migrate_compress_threads_join(); 832 qemu_fclose(s->to_dst_file); 833 s->to_dst_file = NULL; 834 } 835 836 assert((s->state != MIGRATION_STATUS_ACTIVE) && 837 (s->state != MIGRATION_STATUS_POSTCOPY_ACTIVE)); 838 839 if (s->state == MIGRATION_STATUS_CANCELLING) { 840 migrate_set_state(&s->state, MIGRATION_STATUS_CANCELLING, 841 MIGRATION_STATUS_CANCELLED); 842 } 843 844 notifier_list_notify(&migration_state_notifiers, s); 845 } 846 847 void migrate_fd_error(MigrationState *s) 848 { 849 trace_migrate_fd_error(); 850 assert(s->to_dst_file == NULL); 851 migrate_set_state(&s->state, MIGRATION_STATUS_SETUP, 852 MIGRATION_STATUS_FAILED); 853 notifier_list_notify(&migration_state_notifiers, s); 854 } 855 856 static void migrate_fd_cancel(MigrationState *s) 857 { 858 int old_state ; 859 QEMUFile *f = migrate_get_current()->to_dst_file; 860 trace_migrate_fd_cancel(); 861 862 if (s->rp_state.from_dst_file) { 863 /* shutdown the rp socket, so causing the rp thread to shutdown */ 864 qemu_file_shutdown(s->rp_state.from_dst_file); 865 } 866 867 do { 868 old_state = s->state; 869 if (!migration_is_setup_or_active(old_state)) { 870 break; 871 } 872 migrate_set_state(&s->state, old_state, MIGRATION_STATUS_CANCELLING); 873 } while (s->state != MIGRATION_STATUS_CANCELLING); 874 875 /* 876 * If we're unlucky the migration code might be stuck somewhere in a 877 * send/write while the network has failed and is waiting to timeout; 878 * if we've got shutdown(2) available then we can force it to quit. 879 * The outgoing qemu file gets closed in migrate_fd_cleanup that is 880 * called in a bh, so there is no race against this cancel. 881 */ 882 if (s->state == MIGRATION_STATUS_CANCELLING && f) { 883 qemu_file_shutdown(f); 884 } 885 } 886 887 void add_migration_state_change_notifier(Notifier *notify) 888 { 889 notifier_list_add(&migration_state_notifiers, notify); 890 } 891 892 void remove_migration_state_change_notifier(Notifier *notify) 893 { 894 notifier_remove(notify); 895 } 896 897 bool migration_in_setup(MigrationState *s) 898 { 899 return s->state == MIGRATION_STATUS_SETUP; 900 } 901 902 bool migration_has_finished(MigrationState *s) 903 { 904 return s->state == MIGRATION_STATUS_COMPLETED; 905 } 906 907 bool migration_has_failed(MigrationState *s) 908 { 909 return (s->state == MIGRATION_STATUS_CANCELLED || 910 s->state == MIGRATION_STATUS_FAILED); 911 } 912 913 bool migration_in_postcopy(MigrationState *s) 914 { 915 return (s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE); 916 } 917 918 bool migration_in_postcopy_after_devices(MigrationState *s) 919 { 920 return migration_in_postcopy(s) && s->postcopy_after_devices; 921 } 922 923 MigrationState *migrate_init(const MigrationParams *params) 924 { 925 MigrationState *s = migrate_get_current(); 926 927 /* 928 * Reinitialise all migration state, except 929 * parameters/capabilities that the user set, and 930 * locks. 931 */ 932 s->bytes_xfer = 0; 933 s->xfer_limit = 0; 934 s->cleanup_bh = 0; 935 s->to_dst_file = NULL; 936 s->state = MIGRATION_STATUS_NONE; 937 s->params = *params; 938 s->rp_state.from_dst_file = NULL; 939 s->rp_state.error = false; 940 s->mbps = 0.0; 941 s->downtime = 0; 942 s->expected_downtime = 0; 943 s->dirty_pages_rate = 0; 944 s->dirty_bytes_rate = 0; 945 s->setup_time = 0; 946 s->dirty_sync_count = 0; 947 s->start_postcopy = false; 948 s->postcopy_after_devices = false; 949 s->migration_thread_running = false; 950 s->last_req_rb = NULL; 951 952 migrate_set_state(&s->state, MIGRATION_STATUS_NONE, MIGRATION_STATUS_SETUP); 953 954 QSIMPLEQ_INIT(&s->src_page_requests); 955 956 s->total_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); 957 return s; 958 } 959 960 static GSList *migration_blockers; 961 962 void migrate_add_blocker(Error *reason) 963 { 964 migration_blockers = g_slist_prepend(migration_blockers, reason); 965 } 966 967 void migrate_del_blocker(Error *reason) 968 { 969 migration_blockers = g_slist_remove(migration_blockers, reason); 970 } 971 972 void qmp_migrate_incoming(const char *uri, Error **errp) 973 { 974 Error *local_err = NULL; 975 static bool once = true; 976 977 if (!deferred_incoming) { 978 error_setg(errp, "For use with '-incoming defer'"); 979 return; 980 } 981 if (!once) { 982 error_setg(errp, "The incoming migration has already been started"); 983 } 984 985 qemu_start_incoming_migration(uri, &local_err); 986 987 if (local_err) { 988 error_propagate(errp, local_err); 989 return; 990 } 991 992 once = false; 993 } 994 995 void qmp_migrate(const char *uri, bool has_blk, bool blk, 996 bool has_inc, bool inc, bool has_detach, bool detach, 997 Error **errp) 998 { 999 Error *local_err = NULL; 1000 MigrationState *s = migrate_get_current(); 1001 MigrationParams params; 1002 const char *p; 1003 1004 params.blk = has_blk && blk; 1005 params.shared = has_inc && inc; 1006 1007 if (migration_is_setup_or_active(s->state) || 1008 s->state == MIGRATION_STATUS_CANCELLING) { 1009 error_setg(errp, QERR_MIGRATION_ACTIVE); 1010 return; 1011 } 1012 if (runstate_check(RUN_STATE_INMIGRATE)) { 1013 error_setg(errp, "Guest is waiting for an incoming migration"); 1014 return; 1015 } 1016 1017 if (qemu_savevm_state_blocked(errp)) { 1018 return; 1019 } 1020 1021 if (migration_blockers) { 1022 *errp = error_copy(migration_blockers->data); 1023 return; 1024 } 1025 1026 s = migrate_init(¶ms); 1027 1028 if (strstart(uri, "tcp:", &p)) { 1029 tcp_start_outgoing_migration(s, p, &local_err); 1030 #ifdef CONFIG_RDMA 1031 } else if (strstart(uri, "rdma:", &p)) { 1032 rdma_start_outgoing_migration(s, p, &local_err); 1033 #endif 1034 #if !defined(WIN32) 1035 } else if (strstart(uri, "exec:", &p)) { 1036 exec_start_outgoing_migration(s, p, &local_err); 1037 } else if (strstart(uri, "unix:", &p)) { 1038 unix_start_outgoing_migration(s, p, &local_err); 1039 } else if (strstart(uri, "fd:", &p)) { 1040 fd_start_outgoing_migration(s, p, &local_err); 1041 #endif 1042 } else { 1043 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "uri", 1044 "a valid migration protocol"); 1045 migrate_set_state(&s->state, MIGRATION_STATUS_SETUP, 1046 MIGRATION_STATUS_FAILED); 1047 return; 1048 } 1049 1050 if (local_err) { 1051 migrate_fd_error(s); 1052 error_propagate(errp, local_err); 1053 return; 1054 } 1055 } 1056 1057 void qmp_migrate_cancel(Error **errp) 1058 { 1059 migrate_fd_cancel(migrate_get_current()); 1060 } 1061 1062 void qmp_migrate_set_cache_size(int64_t value, Error **errp) 1063 { 1064 MigrationState *s = migrate_get_current(); 1065 int64_t new_size; 1066 1067 /* Check for truncation */ 1068 if (value != (size_t)value) { 1069 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cache size", 1070 "exceeding address space"); 1071 return; 1072 } 1073 1074 /* Cache should not be larger than guest ram size */ 1075 if (value > ram_bytes_total()) { 1076 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cache size", 1077 "exceeds guest ram size "); 1078 return; 1079 } 1080 1081 new_size = xbzrle_cache_resize(value); 1082 if (new_size < 0) { 1083 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cache size", 1084 "is smaller than page size"); 1085 return; 1086 } 1087 1088 s->xbzrle_cache_size = new_size; 1089 } 1090 1091 int64_t qmp_query_migrate_cache_size(Error **errp) 1092 { 1093 return migrate_xbzrle_cache_size(); 1094 } 1095 1096 void qmp_migrate_set_speed(int64_t value, Error **errp) 1097 { 1098 MigrationState *s; 1099 1100 if (value < 0) { 1101 value = 0; 1102 } 1103 if (value > SIZE_MAX) { 1104 value = SIZE_MAX; 1105 } 1106 1107 s = migrate_get_current(); 1108 s->bandwidth_limit = value; 1109 if (s->to_dst_file) { 1110 qemu_file_set_rate_limit(s->to_dst_file, 1111 s->bandwidth_limit / XFER_LIMIT_RATIO); 1112 } 1113 } 1114 1115 void qmp_migrate_set_downtime(double value, Error **errp) 1116 { 1117 value *= 1e9; 1118 value = MAX(0, MIN(UINT64_MAX, value)); 1119 max_downtime = (uint64_t)value; 1120 } 1121 1122 bool migrate_postcopy_ram(void) 1123 { 1124 MigrationState *s; 1125 1126 s = migrate_get_current(); 1127 1128 return s->enabled_capabilities[MIGRATION_CAPABILITY_POSTCOPY_RAM]; 1129 } 1130 1131 bool migrate_auto_converge(void) 1132 { 1133 MigrationState *s; 1134 1135 s = migrate_get_current(); 1136 1137 return s->enabled_capabilities[MIGRATION_CAPABILITY_AUTO_CONVERGE]; 1138 } 1139 1140 bool migrate_zero_blocks(void) 1141 { 1142 MigrationState *s; 1143 1144 s = migrate_get_current(); 1145 1146 return s->enabled_capabilities[MIGRATION_CAPABILITY_ZERO_BLOCKS]; 1147 } 1148 1149 bool migrate_use_compression(void) 1150 { 1151 MigrationState *s; 1152 1153 s = migrate_get_current(); 1154 1155 return s->enabled_capabilities[MIGRATION_CAPABILITY_COMPRESS]; 1156 } 1157 1158 int migrate_compress_level(void) 1159 { 1160 MigrationState *s; 1161 1162 s = migrate_get_current(); 1163 1164 return s->parameters[MIGRATION_PARAMETER_COMPRESS_LEVEL]; 1165 } 1166 1167 int migrate_compress_threads(void) 1168 { 1169 MigrationState *s; 1170 1171 s = migrate_get_current(); 1172 1173 return s->parameters[MIGRATION_PARAMETER_COMPRESS_THREADS]; 1174 } 1175 1176 int migrate_decompress_threads(void) 1177 { 1178 MigrationState *s; 1179 1180 s = migrate_get_current(); 1181 1182 return s->parameters[MIGRATION_PARAMETER_DECOMPRESS_THREADS]; 1183 } 1184 1185 bool migrate_use_events(void) 1186 { 1187 MigrationState *s; 1188 1189 s = migrate_get_current(); 1190 1191 return s->enabled_capabilities[MIGRATION_CAPABILITY_EVENTS]; 1192 } 1193 1194 int migrate_use_xbzrle(void) 1195 { 1196 MigrationState *s; 1197 1198 s = migrate_get_current(); 1199 1200 return s->enabled_capabilities[MIGRATION_CAPABILITY_XBZRLE]; 1201 } 1202 1203 int64_t migrate_xbzrle_cache_size(void) 1204 { 1205 MigrationState *s; 1206 1207 s = migrate_get_current(); 1208 1209 return s->xbzrle_cache_size; 1210 } 1211 1212 /* migration thread support */ 1213 /* 1214 * Something bad happened to the RP stream, mark an error 1215 * The caller shall print or trace something to indicate why 1216 */ 1217 static void mark_source_rp_bad(MigrationState *s) 1218 { 1219 s->rp_state.error = true; 1220 } 1221 1222 static struct rp_cmd_args { 1223 ssize_t len; /* -1 = variable */ 1224 const char *name; 1225 } rp_cmd_args[] = { 1226 [MIG_RP_MSG_INVALID] = { .len = -1, .name = "INVALID" }, 1227 [MIG_RP_MSG_SHUT] = { .len = 4, .name = "SHUT" }, 1228 [MIG_RP_MSG_PONG] = { .len = 4, .name = "PONG" }, 1229 [MIG_RP_MSG_REQ_PAGES] = { .len = 12, .name = "REQ_PAGES" }, 1230 [MIG_RP_MSG_REQ_PAGES_ID] = { .len = -1, .name = "REQ_PAGES_ID" }, 1231 [MIG_RP_MSG_MAX] = { .len = -1, .name = "MAX" }, 1232 }; 1233 1234 /* 1235 * Process a request for pages received on the return path, 1236 * We're allowed to send more than requested (e.g. to round to our page size) 1237 * and we don't need to send pages that have already been sent. 1238 */ 1239 static void migrate_handle_rp_req_pages(MigrationState *ms, const char* rbname, 1240 ram_addr_t start, size_t len) 1241 { 1242 long our_host_ps = getpagesize(); 1243 1244 trace_migrate_handle_rp_req_pages(rbname, start, len); 1245 1246 /* 1247 * Since we currently insist on matching page sizes, just sanity check 1248 * we're being asked for whole host pages. 1249 */ 1250 if (start & (our_host_ps-1) || 1251 (len & (our_host_ps-1))) { 1252 error_report("%s: Misaligned page request, start: " RAM_ADDR_FMT 1253 " len: %zd", __func__, start, len); 1254 mark_source_rp_bad(ms); 1255 return; 1256 } 1257 1258 if (ram_save_queue_pages(ms, rbname, start, len)) { 1259 mark_source_rp_bad(ms); 1260 } 1261 } 1262 1263 /* 1264 * Handles messages sent on the return path towards the source VM 1265 * 1266 */ 1267 static void *source_return_path_thread(void *opaque) 1268 { 1269 MigrationState *ms = opaque; 1270 QEMUFile *rp = ms->rp_state.from_dst_file; 1271 uint16_t header_len, header_type; 1272 uint8_t buf[512]; 1273 uint32_t tmp32, sibling_error; 1274 ram_addr_t start = 0; /* =0 to silence warning */ 1275 size_t len = 0, expected_len; 1276 int res; 1277 1278 trace_source_return_path_thread_entry(); 1279 while (!ms->rp_state.error && !qemu_file_get_error(rp) && 1280 migration_is_setup_or_active(ms->state)) { 1281 trace_source_return_path_thread_loop_top(); 1282 header_type = qemu_get_be16(rp); 1283 header_len = qemu_get_be16(rp); 1284 1285 if (header_type >= MIG_RP_MSG_MAX || 1286 header_type == MIG_RP_MSG_INVALID) { 1287 error_report("RP: Received invalid message 0x%04x length 0x%04x", 1288 header_type, header_len); 1289 mark_source_rp_bad(ms); 1290 goto out; 1291 } 1292 1293 if ((rp_cmd_args[header_type].len != -1 && 1294 header_len != rp_cmd_args[header_type].len) || 1295 header_len > sizeof(buf)) { 1296 error_report("RP: Received '%s' message (0x%04x) with" 1297 "incorrect length %d expecting %zu", 1298 rp_cmd_args[header_type].name, header_type, header_len, 1299 (size_t)rp_cmd_args[header_type].len); 1300 mark_source_rp_bad(ms); 1301 goto out; 1302 } 1303 1304 /* We know we've got a valid header by this point */ 1305 res = qemu_get_buffer(rp, buf, header_len); 1306 if (res != header_len) { 1307 error_report("RP: Failed reading data for message 0x%04x" 1308 " read %d expected %d", 1309 header_type, res, header_len); 1310 mark_source_rp_bad(ms); 1311 goto out; 1312 } 1313 1314 /* OK, we have the message and the data */ 1315 switch (header_type) { 1316 case MIG_RP_MSG_SHUT: 1317 sibling_error = be32_to_cpup((uint32_t *)buf); 1318 trace_source_return_path_thread_shut(sibling_error); 1319 if (sibling_error) { 1320 error_report("RP: Sibling indicated error %d", sibling_error); 1321 mark_source_rp_bad(ms); 1322 } 1323 /* 1324 * We'll let the main thread deal with closing the RP 1325 * we could do a shutdown(2) on it, but we're the only user 1326 * anyway, so there's nothing gained. 1327 */ 1328 goto out; 1329 1330 case MIG_RP_MSG_PONG: 1331 tmp32 = be32_to_cpup((uint32_t *)buf); 1332 trace_source_return_path_thread_pong(tmp32); 1333 break; 1334 1335 case MIG_RP_MSG_REQ_PAGES: 1336 start = be64_to_cpup((uint64_t *)buf); 1337 len = be32_to_cpup((uint32_t *)(buf + 8)); 1338 migrate_handle_rp_req_pages(ms, NULL, start, len); 1339 break; 1340 1341 case MIG_RP_MSG_REQ_PAGES_ID: 1342 expected_len = 12 + 1; /* header + termination */ 1343 1344 if (header_len >= expected_len) { 1345 start = be64_to_cpup((uint64_t *)buf); 1346 len = be32_to_cpup((uint32_t *)(buf + 8)); 1347 /* Now we expect an idstr */ 1348 tmp32 = buf[12]; /* Length of the following idstr */ 1349 buf[13 + tmp32] = '\0'; 1350 expected_len += tmp32; 1351 } 1352 if (header_len != expected_len) { 1353 error_report("RP: Req_Page_id with length %d expecting %zd", 1354 header_len, expected_len); 1355 mark_source_rp_bad(ms); 1356 goto out; 1357 } 1358 migrate_handle_rp_req_pages(ms, (char *)&buf[13], start, len); 1359 break; 1360 1361 default: 1362 break; 1363 } 1364 } 1365 if (qemu_file_get_error(rp)) { 1366 trace_source_return_path_thread_bad_end(); 1367 mark_source_rp_bad(ms); 1368 } 1369 1370 trace_source_return_path_thread_end(); 1371 out: 1372 ms->rp_state.from_dst_file = NULL; 1373 qemu_fclose(rp); 1374 return NULL; 1375 } 1376 1377 static int open_return_path_on_source(MigrationState *ms) 1378 { 1379 1380 ms->rp_state.from_dst_file = qemu_file_get_return_path(ms->to_dst_file); 1381 if (!ms->rp_state.from_dst_file) { 1382 return -1; 1383 } 1384 1385 trace_open_return_path_on_source(); 1386 qemu_thread_create(&ms->rp_state.rp_thread, "return path", 1387 source_return_path_thread, ms, QEMU_THREAD_JOINABLE); 1388 1389 trace_open_return_path_on_source_continue(); 1390 1391 return 0; 1392 } 1393 1394 /* Returns 0 if the RP was ok, otherwise there was an error on the RP */ 1395 static int await_return_path_close_on_source(MigrationState *ms) 1396 { 1397 /* 1398 * If this is a normal exit then the destination will send a SHUT and the 1399 * rp_thread will exit, however if there's an error we need to cause 1400 * it to exit. 1401 */ 1402 if (qemu_file_get_error(ms->to_dst_file) && ms->rp_state.from_dst_file) { 1403 /* 1404 * shutdown(2), if we have it, will cause it to unblock if it's stuck 1405 * waiting for the destination. 1406 */ 1407 qemu_file_shutdown(ms->rp_state.from_dst_file); 1408 mark_source_rp_bad(ms); 1409 } 1410 trace_await_return_path_close_on_source_joining(); 1411 qemu_thread_join(&ms->rp_state.rp_thread); 1412 trace_await_return_path_close_on_source_close(); 1413 return ms->rp_state.error; 1414 } 1415 1416 /* 1417 * Switch from normal iteration to postcopy 1418 * Returns non-0 on error 1419 */ 1420 static int postcopy_start(MigrationState *ms, bool *old_vm_running) 1421 { 1422 int ret; 1423 const QEMUSizedBuffer *qsb; 1424 int64_t time_at_stop = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); 1425 migrate_set_state(&ms->state, MIGRATION_STATUS_ACTIVE, 1426 MIGRATION_STATUS_POSTCOPY_ACTIVE); 1427 1428 trace_postcopy_start(); 1429 qemu_mutex_lock_iothread(); 1430 trace_postcopy_start_set_run(); 1431 1432 qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER); 1433 *old_vm_running = runstate_is_running(); 1434 global_state_store(); 1435 ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE); 1436 if (ret < 0) { 1437 goto fail; 1438 } 1439 1440 ret = bdrv_inactivate_all(); 1441 if (ret < 0) { 1442 goto fail; 1443 } 1444 1445 /* 1446 * Cause any non-postcopiable, but iterative devices to 1447 * send out their final data. 1448 */ 1449 qemu_savevm_state_complete_precopy(ms->to_dst_file, true); 1450 1451 /* 1452 * in Finish migrate and with the io-lock held everything should 1453 * be quiet, but we've potentially still got dirty pages and we 1454 * need to tell the destination to throw any pages it's already received 1455 * that are dirty 1456 */ 1457 if (ram_postcopy_send_discard_bitmap(ms)) { 1458 error_report("postcopy send discard bitmap failed"); 1459 goto fail; 1460 } 1461 1462 /* 1463 * send rest of state - note things that are doing postcopy 1464 * will notice we're in POSTCOPY_ACTIVE and not actually 1465 * wrap their state up here 1466 */ 1467 qemu_file_set_rate_limit(ms->to_dst_file, INT64_MAX); 1468 /* Ping just for debugging, helps line traces up */ 1469 qemu_savevm_send_ping(ms->to_dst_file, 2); 1470 1471 /* 1472 * While loading the device state we may trigger page transfer 1473 * requests and the fd must be free to process those, and thus 1474 * the destination must read the whole device state off the fd before 1475 * it starts processing it. Unfortunately the ad-hoc migration format 1476 * doesn't allow the destination to know the size to read without fully 1477 * parsing it through each devices load-state code (especially the open 1478 * coded devices that use get/put). 1479 * So we wrap the device state up in a package with a length at the start; 1480 * to do this we use a qemu_buf to hold the whole of the device state. 1481 */ 1482 QEMUFile *fb = qemu_bufopen("w", NULL); 1483 if (!fb) { 1484 error_report("Failed to create buffered file"); 1485 goto fail; 1486 } 1487 1488 /* 1489 * Make sure the receiver can get incoming pages before we send the rest 1490 * of the state 1491 */ 1492 qemu_savevm_send_postcopy_listen(fb); 1493 1494 qemu_savevm_state_complete_precopy(fb, false); 1495 qemu_savevm_send_ping(fb, 3); 1496 1497 qemu_savevm_send_postcopy_run(fb); 1498 1499 /* <><> end of stuff going into the package */ 1500 qsb = qemu_buf_get(fb); 1501 1502 /* Now send that blob */ 1503 if (qemu_savevm_send_packaged(ms->to_dst_file, qsb)) { 1504 goto fail_closefb; 1505 } 1506 qemu_fclose(fb); 1507 1508 /* Send a notify to give a chance for anything that needs to happen 1509 * at the transition to postcopy and after the device state; in particular 1510 * spice needs to trigger a transition now 1511 */ 1512 ms->postcopy_after_devices = true; 1513 notifier_list_notify(&migration_state_notifiers, ms); 1514 1515 ms->downtime = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) - time_at_stop; 1516 1517 qemu_mutex_unlock_iothread(); 1518 1519 /* 1520 * Although this ping is just for debug, it could potentially be 1521 * used for getting a better measurement of downtime at the source. 1522 */ 1523 qemu_savevm_send_ping(ms->to_dst_file, 4); 1524 1525 ret = qemu_file_get_error(ms->to_dst_file); 1526 if (ret) { 1527 error_report("postcopy_start: Migration stream errored"); 1528 migrate_set_state(&ms->state, MIGRATION_STATUS_POSTCOPY_ACTIVE, 1529 MIGRATION_STATUS_FAILED); 1530 } 1531 1532 return ret; 1533 1534 fail_closefb: 1535 qemu_fclose(fb); 1536 fail: 1537 migrate_set_state(&ms->state, MIGRATION_STATUS_POSTCOPY_ACTIVE, 1538 MIGRATION_STATUS_FAILED); 1539 qemu_mutex_unlock_iothread(); 1540 return -1; 1541 } 1542 1543 /** 1544 * migration_completion: Used by migration_thread when there's not much left. 1545 * The caller 'breaks' the loop when this returns. 1546 * 1547 * @s: Current migration state 1548 * @current_active_state: The migration state we expect to be in 1549 * @*old_vm_running: Pointer to old_vm_running flag 1550 * @*start_time: Pointer to time to update 1551 */ 1552 static void migration_completion(MigrationState *s, int current_active_state, 1553 bool *old_vm_running, 1554 int64_t *start_time) 1555 { 1556 int ret; 1557 1558 if (s->state == MIGRATION_STATUS_ACTIVE) { 1559 qemu_mutex_lock_iothread(); 1560 *start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); 1561 qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER); 1562 *old_vm_running = runstate_is_running(); 1563 ret = global_state_store(); 1564 1565 if (!ret) { 1566 ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE); 1567 if (ret >= 0) { 1568 ret = bdrv_inactivate_all(); 1569 } 1570 if (ret >= 0) { 1571 qemu_file_set_rate_limit(s->to_dst_file, INT64_MAX); 1572 qemu_savevm_state_complete_precopy(s->to_dst_file, false); 1573 } 1574 } 1575 qemu_mutex_unlock_iothread(); 1576 1577 if (ret < 0) { 1578 goto fail; 1579 } 1580 } else if (s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE) { 1581 trace_migration_completion_postcopy_end(); 1582 1583 qemu_savevm_state_complete_postcopy(s->to_dst_file); 1584 trace_migration_completion_postcopy_end_after_complete(); 1585 } 1586 1587 /* 1588 * If rp was opened we must clean up the thread before 1589 * cleaning everything else up (since if there are no failures 1590 * it will wait for the destination to send it's status in 1591 * a SHUT command). 1592 * Postcopy opens rp if enabled (even if it's not avtivated) 1593 */ 1594 if (migrate_postcopy_ram()) { 1595 int rp_error; 1596 trace_migration_completion_postcopy_end_before_rp(); 1597 rp_error = await_return_path_close_on_source(s); 1598 trace_migration_completion_postcopy_end_after_rp(rp_error); 1599 if (rp_error) { 1600 goto fail; 1601 } 1602 } 1603 1604 if (qemu_file_get_error(s->to_dst_file)) { 1605 trace_migration_completion_file_err(); 1606 goto fail; 1607 } 1608 1609 migrate_set_state(&s->state, current_active_state, 1610 MIGRATION_STATUS_COMPLETED); 1611 return; 1612 1613 fail: 1614 migrate_set_state(&s->state, current_active_state, 1615 MIGRATION_STATUS_FAILED); 1616 } 1617 1618 /* 1619 * Master migration thread on the source VM. 1620 * It drives the migration and pumps the data down the outgoing channel. 1621 */ 1622 static void *migration_thread(void *opaque) 1623 { 1624 MigrationState *s = opaque; 1625 /* Used by the bandwidth calcs, updated later */ 1626 int64_t initial_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); 1627 int64_t setup_start = qemu_clock_get_ms(QEMU_CLOCK_HOST); 1628 int64_t initial_bytes = 0; 1629 int64_t max_size = 0; 1630 int64_t start_time = initial_time; 1631 int64_t end_time; 1632 bool old_vm_running = false; 1633 bool entered_postcopy = false; 1634 /* The active state we expect to be in; ACTIVE or POSTCOPY_ACTIVE */ 1635 enum MigrationStatus current_active_state = MIGRATION_STATUS_ACTIVE; 1636 1637 rcu_register_thread(); 1638 1639 qemu_savevm_state_header(s->to_dst_file); 1640 1641 if (migrate_postcopy_ram()) { 1642 /* Now tell the dest that it should open its end so it can reply */ 1643 qemu_savevm_send_open_return_path(s->to_dst_file); 1644 1645 /* And do a ping that will make stuff easier to debug */ 1646 qemu_savevm_send_ping(s->to_dst_file, 1); 1647 1648 /* 1649 * Tell the destination that we *might* want to do postcopy later; 1650 * if the other end can't do postcopy it should fail now, nice and 1651 * early. 1652 */ 1653 qemu_savevm_send_postcopy_advise(s->to_dst_file); 1654 } 1655 1656 qemu_savevm_state_begin(s->to_dst_file, &s->params); 1657 1658 s->setup_time = qemu_clock_get_ms(QEMU_CLOCK_HOST) - setup_start; 1659 current_active_state = MIGRATION_STATUS_ACTIVE; 1660 migrate_set_state(&s->state, MIGRATION_STATUS_SETUP, 1661 MIGRATION_STATUS_ACTIVE); 1662 1663 trace_migration_thread_setup_complete(); 1664 1665 while (s->state == MIGRATION_STATUS_ACTIVE || 1666 s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE) { 1667 int64_t current_time; 1668 uint64_t pending_size; 1669 1670 if (!qemu_file_rate_limit(s->to_dst_file)) { 1671 uint64_t pend_post, pend_nonpost; 1672 1673 qemu_savevm_state_pending(s->to_dst_file, max_size, &pend_nonpost, 1674 &pend_post); 1675 pending_size = pend_nonpost + pend_post; 1676 trace_migrate_pending(pending_size, max_size, 1677 pend_post, pend_nonpost); 1678 if (pending_size && pending_size >= max_size) { 1679 /* Still a significant amount to transfer */ 1680 1681 if (migrate_postcopy_ram() && 1682 s->state != MIGRATION_STATUS_POSTCOPY_ACTIVE && 1683 pend_nonpost <= max_size && 1684 atomic_read(&s->start_postcopy)) { 1685 1686 if (!postcopy_start(s, &old_vm_running)) { 1687 current_active_state = MIGRATION_STATUS_POSTCOPY_ACTIVE; 1688 entered_postcopy = true; 1689 } 1690 1691 continue; 1692 } 1693 /* Just another iteration step */ 1694 qemu_savevm_state_iterate(s->to_dst_file, entered_postcopy); 1695 } else { 1696 trace_migration_thread_low_pending(pending_size); 1697 migration_completion(s, current_active_state, 1698 &old_vm_running, &start_time); 1699 break; 1700 } 1701 } 1702 1703 if (qemu_file_get_error(s->to_dst_file)) { 1704 migrate_set_state(&s->state, current_active_state, 1705 MIGRATION_STATUS_FAILED); 1706 trace_migration_thread_file_err(); 1707 break; 1708 } 1709 current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); 1710 if (current_time >= initial_time + BUFFER_DELAY) { 1711 uint64_t transferred_bytes = qemu_ftell(s->to_dst_file) - 1712 initial_bytes; 1713 uint64_t time_spent = current_time - initial_time; 1714 double bandwidth = (double)transferred_bytes / time_spent; 1715 max_size = bandwidth * migrate_max_downtime() / 1000000; 1716 1717 s->mbps = (((double) transferred_bytes * 8.0) / 1718 ((double) time_spent / 1000.0)) / 1000.0 / 1000.0; 1719 1720 trace_migrate_transferred(transferred_bytes, time_spent, 1721 bandwidth, max_size); 1722 /* if we haven't sent anything, we don't want to recalculate 1723 10000 is a small enough number for our purposes */ 1724 if (s->dirty_bytes_rate && transferred_bytes > 10000) { 1725 s->expected_downtime = s->dirty_bytes_rate / bandwidth; 1726 } 1727 1728 qemu_file_reset_rate_limit(s->to_dst_file); 1729 initial_time = current_time; 1730 initial_bytes = qemu_ftell(s->to_dst_file); 1731 } 1732 if (qemu_file_rate_limit(s->to_dst_file)) { 1733 /* usleep expects microseconds */ 1734 g_usleep((initial_time + BUFFER_DELAY - current_time)*1000); 1735 } 1736 } 1737 1738 trace_migration_thread_after_loop(); 1739 /* If we enabled cpu throttling for auto-converge, turn it off. */ 1740 cpu_throttle_stop(); 1741 end_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); 1742 1743 qemu_mutex_lock_iothread(); 1744 qemu_savevm_state_cleanup(); 1745 if (s->state == MIGRATION_STATUS_COMPLETED) { 1746 uint64_t transferred_bytes = qemu_ftell(s->to_dst_file); 1747 s->total_time = end_time - s->total_time; 1748 if (!entered_postcopy) { 1749 s->downtime = end_time - start_time; 1750 } 1751 if (s->total_time) { 1752 s->mbps = (((double) transferred_bytes * 8.0) / 1753 ((double) s->total_time)) / 1000; 1754 } 1755 runstate_set(RUN_STATE_POSTMIGRATE); 1756 } else { 1757 if (old_vm_running && !entered_postcopy) { 1758 vm_start(); 1759 } 1760 } 1761 qemu_bh_schedule(s->cleanup_bh); 1762 qemu_mutex_unlock_iothread(); 1763 1764 rcu_unregister_thread(); 1765 return NULL; 1766 } 1767 1768 void migrate_fd_connect(MigrationState *s) 1769 { 1770 /* This is a best 1st approximation. ns to ms */ 1771 s->expected_downtime = max_downtime/1000000; 1772 s->cleanup_bh = qemu_bh_new(migrate_fd_cleanup, s); 1773 1774 qemu_file_set_rate_limit(s->to_dst_file, 1775 s->bandwidth_limit / XFER_LIMIT_RATIO); 1776 1777 /* Notify before starting migration thread */ 1778 notifier_list_notify(&migration_state_notifiers, s); 1779 1780 /* 1781 * Open the return path; currently for postcopy but other things might 1782 * also want it. 1783 */ 1784 if (migrate_postcopy_ram()) { 1785 if (open_return_path_on_source(s)) { 1786 error_report("Unable to open return-path for postcopy"); 1787 migrate_set_state(&s->state, MIGRATION_STATUS_SETUP, 1788 MIGRATION_STATUS_FAILED); 1789 migrate_fd_cleanup(s); 1790 return; 1791 } 1792 } 1793 1794 migrate_compress_threads_create(); 1795 qemu_thread_create(&s->thread, "migration", migration_thread, s, 1796 QEMU_THREAD_JOINABLE); 1797 s->migration_thread_running = true; 1798 } 1799 1800 PostcopyState postcopy_state_get(void) 1801 { 1802 return atomic_mb_read(&incoming_postcopy_state); 1803 } 1804 1805 /* Set the state and return the old state */ 1806 PostcopyState postcopy_state_set(PostcopyState new_state) 1807 { 1808 return atomic_xchg(&incoming_postcopy_state, new_state); 1809 } 1810 1811