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