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/cutils.h" 18 #include "qemu/error-report.h" 19 #include "qemu/main-loop.h" 20 #include "migration/blocker.h" 21 #include "exec.h" 22 #include "fd.h" 23 #include "socket.h" 24 #include "rdma.h" 25 #include "ram.h" 26 #include "migration/global_state.h" 27 #include "migration/misc.h" 28 #include "migration.h" 29 #include "savevm.h" 30 #include "qemu-file-channel.h" 31 #include "qemu-file.h" 32 #include "migration/vmstate.h" 33 #include "sysemu/sysemu.h" 34 #include "block/block.h" 35 #include "qapi/qmp/qerror.h" 36 #include "qapi/util.h" 37 #include "qemu/sockets.h" 38 #include "qemu/rcu.h" 39 #include "block.h" 40 #include "postcopy-ram.h" 41 #include "qemu/thread.h" 42 #include "qmp-commands.h" 43 #include "trace.h" 44 #include "qapi-event.h" 45 #include "qom/cpu.h" 46 #include "exec/memory.h" 47 #include "exec/address-spaces.h" 48 #include "exec/target_page.h" 49 #include "io/channel-buffer.h" 50 #include "migration/colo.h" 51 52 #define MAX_THROTTLE (32 << 20) /* Migration transfer speed throttling */ 53 54 /* Amount of time to allocate to each "chunk" of bandwidth-throttled 55 * data. */ 56 #define BUFFER_DELAY 100 57 #define XFER_LIMIT_RATIO (1000 / BUFFER_DELAY) 58 59 /* Time in milliseconds we are allowed to stop the source, 60 * for sending the last part */ 61 #define DEFAULT_MIGRATE_SET_DOWNTIME 300 62 63 /* Maximum migrate downtime set to 2000 seconds */ 64 #define MAX_MIGRATE_DOWNTIME_SECONDS 2000 65 #define MAX_MIGRATE_DOWNTIME (MAX_MIGRATE_DOWNTIME_SECONDS * 1000) 66 67 /* Default compression thread count */ 68 #define DEFAULT_MIGRATE_COMPRESS_THREAD_COUNT 8 69 /* Default decompression thread count, usually decompression is at 70 * least 4 times as fast as compression.*/ 71 #define DEFAULT_MIGRATE_DECOMPRESS_THREAD_COUNT 2 72 /*0: means nocompress, 1: best speed, ... 9: best compress ratio */ 73 #define DEFAULT_MIGRATE_COMPRESS_LEVEL 1 74 /* Define default autoconverge cpu throttle migration parameters */ 75 #define DEFAULT_MIGRATE_CPU_THROTTLE_INITIAL 20 76 #define DEFAULT_MIGRATE_CPU_THROTTLE_INCREMENT 10 77 78 /* Migration XBZRLE default cache size */ 79 #define DEFAULT_MIGRATE_CACHE_SIZE (64 * 1024 * 1024) 80 81 /* The delay time (in ms) between two COLO checkpoints 82 * Note: Please change this default value to 10000 when we support hybrid mode. 83 */ 84 #define DEFAULT_MIGRATE_X_CHECKPOINT_DELAY 200 85 86 static NotifierList migration_state_notifiers = 87 NOTIFIER_LIST_INITIALIZER(migration_state_notifiers); 88 89 static bool deferred_incoming; 90 91 /* Messages sent on the return path from destination to source */ 92 enum mig_rp_message_type { 93 MIG_RP_MSG_INVALID = 0, /* Must be 0 */ 94 MIG_RP_MSG_SHUT, /* sibling will not send any more RP messages */ 95 MIG_RP_MSG_PONG, /* Response to a PING; data (seq: be32 ) */ 96 97 MIG_RP_MSG_REQ_PAGES_ID, /* data (start: be64, len: be32, id: string) */ 98 MIG_RP_MSG_REQ_PAGES, /* data (start: be64, len: be32) */ 99 100 MIG_RP_MSG_MAX 101 }; 102 103 /* When we add fault tolerance, we could have several 104 migrations at once. For now we don't need to add 105 dynamic creation of migration */ 106 107 /* For outgoing */ 108 MigrationState *migrate_get_current(void) 109 { 110 static bool once; 111 static MigrationState current_migration = { 112 .state = MIGRATION_STATUS_NONE, 113 .xbzrle_cache_size = DEFAULT_MIGRATE_CACHE_SIZE, 114 .mbps = -1, 115 .parameters = { 116 .compress_level = DEFAULT_MIGRATE_COMPRESS_LEVEL, 117 .compress_threads = DEFAULT_MIGRATE_COMPRESS_THREAD_COUNT, 118 .decompress_threads = DEFAULT_MIGRATE_DECOMPRESS_THREAD_COUNT, 119 .cpu_throttle_initial = DEFAULT_MIGRATE_CPU_THROTTLE_INITIAL, 120 .cpu_throttle_increment = DEFAULT_MIGRATE_CPU_THROTTLE_INCREMENT, 121 .max_bandwidth = MAX_THROTTLE, 122 .downtime_limit = DEFAULT_MIGRATE_SET_DOWNTIME, 123 .x_checkpoint_delay = DEFAULT_MIGRATE_X_CHECKPOINT_DELAY, 124 }, 125 }; 126 127 if (!once) { 128 current_migration.parameters.tls_creds = g_strdup(""); 129 current_migration.parameters.tls_hostname = g_strdup(""); 130 once = true; 131 } 132 return ¤t_migration; 133 } 134 135 MigrationIncomingState *migration_incoming_get_current(void) 136 { 137 static bool once; 138 static MigrationIncomingState mis_current; 139 140 if (!once) { 141 mis_current.state = MIGRATION_STATUS_NONE; 142 memset(&mis_current, 0, sizeof(MigrationIncomingState)); 143 qemu_mutex_init(&mis_current.rp_mutex); 144 qemu_event_init(&mis_current.main_thread_load_event, false); 145 once = true; 146 } 147 return &mis_current; 148 } 149 150 void migration_incoming_state_destroy(void) 151 { 152 struct MigrationIncomingState *mis = migration_incoming_get_current(); 153 154 if (mis->to_src_file) { 155 /* Tell source that we are done */ 156 migrate_send_rp_shut(mis, qemu_file_get_error(mis->from_src_file) != 0); 157 qemu_fclose(mis->to_src_file); 158 mis->to_src_file = NULL; 159 } 160 161 if (mis->from_src_file) { 162 qemu_fclose(mis->from_src_file); 163 mis->from_src_file = NULL; 164 } 165 166 qemu_event_destroy(&mis->main_thread_load_event); 167 } 168 169 static void migrate_generate_event(int new_state) 170 { 171 if (migrate_use_events()) { 172 qapi_event_send_migration(new_state, &error_abort); 173 } 174 } 175 176 /* 177 * Called on -incoming with a defer: uri. 178 * The migration can be started later after any parameters have been 179 * changed. 180 */ 181 static void deferred_incoming_migration(Error **errp) 182 { 183 if (deferred_incoming) { 184 error_setg(errp, "Incoming migration already deferred"); 185 } 186 deferred_incoming = true; 187 } 188 189 /* 190 * Send a message on the return channel back to the source 191 * of the migration. 192 */ 193 static void migrate_send_rp_message(MigrationIncomingState *mis, 194 enum mig_rp_message_type message_type, 195 uint16_t len, void *data) 196 { 197 trace_migrate_send_rp_message((int)message_type, len); 198 qemu_mutex_lock(&mis->rp_mutex); 199 qemu_put_be16(mis->to_src_file, (unsigned int)message_type); 200 qemu_put_be16(mis->to_src_file, len); 201 qemu_put_buffer(mis->to_src_file, data, len); 202 qemu_fflush(mis->to_src_file); 203 qemu_mutex_unlock(&mis->rp_mutex); 204 } 205 206 /* Request a range of pages from the source VM at the given 207 * start address. 208 * rbname: Name of the RAMBlock to request the page in, if NULL it's the same 209 * as the last request (a name must have been given previously) 210 * Start: Address offset within the RB 211 * Len: Length in bytes required - must be a multiple of pagesize 212 */ 213 void migrate_send_rp_req_pages(MigrationIncomingState *mis, const char *rbname, 214 ram_addr_t start, size_t len) 215 { 216 uint8_t bufc[12 + 1 + 255]; /* start (8), len (4), rbname up to 256 */ 217 size_t msglen = 12; /* start + len */ 218 219 *(uint64_t *)bufc = cpu_to_be64((uint64_t)start); 220 *(uint32_t *)(bufc + 8) = cpu_to_be32((uint32_t)len); 221 222 if (rbname) { 223 int rbname_len = strlen(rbname); 224 assert(rbname_len < 256); 225 226 bufc[msglen++] = rbname_len; 227 memcpy(bufc + msglen, rbname, rbname_len); 228 msglen += rbname_len; 229 migrate_send_rp_message(mis, MIG_RP_MSG_REQ_PAGES_ID, msglen, bufc); 230 } else { 231 migrate_send_rp_message(mis, MIG_RP_MSG_REQ_PAGES, msglen, bufc); 232 } 233 } 234 235 void qemu_start_incoming_migration(const char *uri, Error **errp) 236 { 237 const char *p; 238 239 qapi_event_send_migration(MIGRATION_STATUS_SETUP, &error_abort); 240 if (!strcmp(uri, "defer")) { 241 deferred_incoming_migration(errp); 242 } else if (strstart(uri, "tcp:", &p)) { 243 tcp_start_incoming_migration(p, errp); 244 #ifdef CONFIG_RDMA 245 } else if (strstart(uri, "rdma:", &p)) { 246 rdma_start_incoming_migration(p, errp); 247 #endif 248 } else if (strstart(uri, "exec:", &p)) { 249 exec_start_incoming_migration(p, errp); 250 } else if (strstart(uri, "unix:", &p)) { 251 unix_start_incoming_migration(p, errp); 252 } else if (strstart(uri, "fd:", &p)) { 253 fd_start_incoming_migration(p, errp); 254 } else { 255 error_setg(errp, "unknown migration protocol: %s", uri); 256 } 257 } 258 259 static void process_incoming_migration_bh(void *opaque) 260 { 261 Error *local_err = NULL; 262 MigrationIncomingState *mis = opaque; 263 264 /* Make sure all file formats flush their mutable metadata. 265 * If we get an error here, just don't restart the VM yet. */ 266 bdrv_invalidate_cache_all(&local_err); 267 if (local_err) { 268 error_report_err(local_err); 269 local_err = NULL; 270 autostart = false; 271 } 272 273 /* 274 * This must happen after all error conditions are dealt with and 275 * we're sure the VM is going to be running on this host. 276 */ 277 qemu_announce_self(); 278 279 /* If global state section was not received or we are in running 280 state, we need to obey autostart. Any other state is set with 281 runstate_set. */ 282 283 if (!global_state_received() || 284 global_state_get_runstate() == RUN_STATE_RUNNING) { 285 if (autostart) { 286 vm_start(); 287 } else { 288 runstate_set(RUN_STATE_PAUSED); 289 } 290 } else { 291 runstate_set(global_state_get_runstate()); 292 } 293 migrate_decompress_threads_join(); 294 /* 295 * This must happen after any state changes since as soon as an external 296 * observer sees this event they might start to prod at the VM assuming 297 * it's ready to use. 298 */ 299 migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE, 300 MIGRATION_STATUS_COMPLETED); 301 qemu_bh_delete(mis->bh); 302 migration_incoming_state_destroy(); 303 } 304 305 static void process_incoming_migration_co(void *opaque) 306 { 307 QEMUFile *f = opaque; 308 MigrationIncomingState *mis = migration_incoming_get_current(); 309 PostcopyState ps; 310 int ret; 311 312 mis->from_src_file = f; 313 mis->largest_page_size = qemu_ram_pagesize_largest(); 314 postcopy_state_set(POSTCOPY_INCOMING_NONE); 315 migrate_set_state(&mis->state, MIGRATION_STATUS_NONE, 316 MIGRATION_STATUS_ACTIVE); 317 ret = qemu_loadvm_state(f); 318 319 ps = postcopy_state_get(); 320 trace_process_incoming_migration_co_end(ret, ps); 321 if (ps != POSTCOPY_INCOMING_NONE) { 322 if (ps == POSTCOPY_INCOMING_ADVISE) { 323 /* 324 * Where a migration had postcopy enabled (and thus went to advise) 325 * but managed to complete within the precopy period, we can use 326 * the normal exit. 327 */ 328 postcopy_ram_incoming_cleanup(mis); 329 } else if (ret >= 0) { 330 /* 331 * Postcopy was started, cleanup should happen at the end of the 332 * postcopy thread. 333 */ 334 trace_process_incoming_migration_co_postcopy_end_main(); 335 return; 336 } 337 /* Else if something went wrong then just fall out of the normal exit */ 338 } 339 340 /* we get COLO info, and know if we are in COLO mode */ 341 if (!ret && migration_incoming_enable_colo()) { 342 mis->migration_incoming_co = qemu_coroutine_self(); 343 qemu_thread_create(&mis->colo_incoming_thread, "COLO incoming", 344 colo_process_incoming_thread, mis, QEMU_THREAD_JOINABLE); 345 mis->have_colo_incoming_thread = true; 346 qemu_coroutine_yield(); 347 348 /* Wait checkpoint incoming thread exit before free resource */ 349 qemu_thread_join(&mis->colo_incoming_thread); 350 } 351 352 if (ret < 0) { 353 migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE, 354 MIGRATION_STATUS_FAILED); 355 error_report("load of migration failed: %s", strerror(-ret)); 356 migrate_decompress_threads_join(); 357 exit(EXIT_FAILURE); 358 } 359 360 free_xbzrle_decoded_buf(); 361 362 mis->bh = qemu_bh_new(process_incoming_migration_bh, mis); 363 qemu_bh_schedule(mis->bh); 364 } 365 366 void migration_fd_process_incoming(QEMUFile *f) 367 { 368 Coroutine *co = qemu_coroutine_create(process_incoming_migration_co, f); 369 370 migrate_decompress_threads_create(); 371 qemu_file_set_blocking(f, false); 372 qemu_coroutine_enter(co); 373 } 374 375 /* 376 * Send a 'SHUT' message on the return channel with the given value 377 * to indicate that we've finished with the RP. Non-0 value indicates 378 * error. 379 */ 380 void migrate_send_rp_shut(MigrationIncomingState *mis, 381 uint32_t value) 382 { 383 uint32_t buf; 384 385 buf = cpu_to_be32(value); 386 migrate_send_rp_message(mis, MIG_RP_MSG_SHUT, sizeof(buf), &buf); 387 } 388 389 /* 390 * Send a 'PONG' message on the return channel with the given value 391 * (normally in response to a 'PING') 392 */ 393 void migrate_send_rp_pong(MigrationIncomingState *mis, 394 uint32_t value) 395 { 396 uint32_t buf; 397 398 buf = cpu_to_be32(value); 399 migrate_send_rp_message(mis, MIG_RP_MSG_PONG, sizeof(buf), &buf); 400 } 401 402 MigrationCapabilityStatusList *qmp_query_migrate_capabilities(Error **errp) 403 { 404 MigrationCapabilityStatusList *head = NULL; 405 MigrationCapabilityStatusList *caps; 406 MigrationState *s = migrate_get_current(); 407 int i; 408 409 caps = NULL; /* silence compiler warning */ 410 for (i = 0; i < MIGRATION_CAPABILITY__MAX; i++) { 411 #ifndef CONFIG_LIVE_BLOCK_MIGRATION 412 if (i == MIGRATION_CAPABILITY_BLOCK) { 413 continue; 414 } 415 #endif 416 if (i == MIGRATION_CAPABILITY_X_COLO && !colo_supported()) { 417 continue; 418 } 419 if (head == NULL) { 420 head = g_malloc0(sizeof(*caps)); 421 caps = head; 422 } else { 423 caps->next = g_malloc0(sizeof(*caps)); 424 caps = caps->next; 425 } 426 caps->value = 427 g_malloc(sizeof(*caps->value)); 428 caps->value->capability = i; 429 caps->value->state = s->enabled_capabilities[i]; 430 } 431 432 return head; 433 } 434 435 MigrationParameters *qmp_query_migrate_parameters(Error **errp) 436 { 437 MigrationParameters *params; 438 MigrationState *s = migrate_get_current(); 439 440 params = g_malloc0(sizeof(*params)); 441 params->has_compress_level = true; 442 params->compress_level = s->parameters.compress_level; 443 params->has_compress_threads = true; 444 params->compress_threads = s->parameters.compress_threads; 445 params->has_decompress_threads = true; 446 params->decompress_threads = s->parameters.decompress_threads; 447 params->has_cpu_throttle_initial = true; 448 params->cpu_throttle_initial = s->parameters.cpu_throttle_initial; 449 params->has_cpu_throttle_increment = true; 450 params->cpu_throttle_increment = s->parameters.cpu_throttle_increment; 451 params->has_tls_creds = !!s->parameters.tls_creds; 452 params->tls_creds = g_strdup(s->parameters.tls_creds); 453 params->has_tls_hostname = !!s->parameters.tls_hostname; 454 params->tls_hostname = g_strdup(s->parameters.tls_hostname); 455 params->has_max_bandwidth = true; 456 params->max_bandwidth = s->parameters.max_bandwidth; 457 params->has_downtime_limit = true; 458 params->downtime_limit = s->parameters.downtime_limit; 459 params->has_x_checkpoint_delay = true; 460 params->x_checkpoint_delay = s->parameters.x_checkpoint_delay; 461 params->has_block_incremental = true; 462 params->block_incremental = s->parameters.block_incremental; 463 464 return params; 465 } 466 467 /* 468 * Return true if we're already in the middle of a migration 469 * (i.e. any of the active or setup states) 470 */ 471 static bool migration_is_setup_or_active(int state) 472 { 473 switch (state) { 474 case MIGRATION_STATUS_ACTIVE: 475 case MIGRATION_STATUS_POSTCOPY_ACTIVE: 476 case MIGRATION_STATUS_SETUP: 477 return true; 478 479 default: 480 return false; 481 482 } 483 } 484 485 static void populate_ram_info(MigrationInfo *info, MigrationState *s) 486 { 487 info->has_ram = true; 488 info->ram = g_malloc0(sizeof(*info->ram)); 489 info->ram->transferred = ram_counters.transferred; 490 info->ram->total = ram_bytes_total(); 491 info->ram->duplicate = ram_counters.duplicate; 492 /* legacy value. It is not used anymore */ 493 info->ram->skipped = 0; 494 info->ram->normal = ram_counters.normal; 495 info->ram->normal_bytes = ram_counters.normal * 496 qemu_target_page_size(); 497 info->ram->mbps = s->mbps; 498 info->ram->dirty_sync_count = ram_counters.dirty_sync_count; 499 info->ram->postcopy_requests = ram_counters.postcopy_requests; 500 info->ram->page_size = qemu_target_page_size(); 501 502 if (migrate_use_xbzrle()) { 503 info->has_xbzrle_cache = true; 504 info->xbzrle_cache = g_malloc0(sizeof(*info->xbzrle_cache)); 505 info->xbzrle_cache->cache_size = migrate_xbzrle_cache_size(); 506 info->xbzrle_cache->bytes = xbzrle_counters.bytes; 507 info->xbzrle_cache->pages = xbzrle_counters.pages; 508 info->xbzrle_cache->cache_miss = xbzrle_counters.cache_miss; 509 info->xbzrle_cache->cache_miss_rate = xbzrle_counters.cache_miss_rate; 510 info->xbzrle_cache->overflow = xbzrle_counters.overflow; 511 } 512 513 if (cpu_throttle_active()) { 514 info->has_cpu_throttle_percentage = true; 515 info->cpu_throttle_percentage = cpu_throttle_get_percentage(); 516 } 517 518 if (s->state != MIGRATION_STATUS_COMPLETED) { 519 info->ram->remaining = ram_bytes_remaining(); 520 info->ram->dirty_pages_rate = ram_counters.dirty_pages_rate; 521 } 522 } 523 524 static void populate_disk_info(MigrationInfo *info) 525 { 526 if (blk_mig_active()) { 527 info->has_disk = true; 528 info->disk = g_malloc0(sizeof(*info->disk)); 529 info->disk->transferred = blk_mig_bytes_transferred(); 530 info->disk->remaining = blk_mig_bytes_remaining(); 531 info->disk->total = blk_mig_bytes_total(); 532 } 533 } 534 535 MigrationInfo *qmp_query_migrate(Error **errp) 536 { 537 MigrationInfo *info = g_malloc0(sizeof(*info)); 538 MigrationState *s = migrate_get_current(); 539 540 switch (s->state) { 541 case MIGRATION_STATUS_NONE: 542 /* no migration has happened ever */ 543 break; 544 case MIGRATION_STATUS_SETUP: 545 info->has_status = true; 546 info->has_total_time = false; 547 break; 548 case MIGRATION_STATUS_ACTIVE: 549 case MIGRATION_STATUS_CANCELLING: 550 case MIGRATION_STATUS_POSTCOPY_ACTIVE: 551 /* TODO add some postcopy stats */ 552 info->has_status = true; 553 info->has_total_time = true; 554 info->total_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) 555 - s->total_time; 556 info->has_expected_downtime = true; 557 info->expected_downtime = s->expected_downtime; 558 info->has_setup_time = true; 559 info->setup_time = s->setup_time; 560 561 populate_ram_info(info, s); 562 populate_disk_info(info); 563 break; 564 case MIGRATION_STATUS_COLO: 565 info->has_status = true; 566 /* TODO: display COLO specific information (checkpoint info etc.) */ 567 break; 568 case MIGRATION_STATUS_COMPLETED: 569 info->has_status = true; 570 info->has_total_time = true; 571 info->total_time = s->total_time; 572 info->has_downtime = true; 573 info->downtime = s->downtime; 574 info->has_setup_time = true; 575 info->setup_time = s->setup_time; 576 577 populate_ram_info(info, s); 578 break; 579 case MIGRATION_STATUS_FAILED: 580 info->has_status = true; 581 if (s->error) { 582 info->has_error_desc = true; 583 info->error_desc = g_strdup(error_get_pretty(s->error)); 584 } 585 break; 586 case MIGRATION_STATUS_CANCELLED: 587 info->has_status = true; 588 break; 589 } 590 info->status = s->state; 591 592 return info; 593 } 594 595 void qmp_migrate_set_capabilities(MigrationCapabilityStatusList *params, 596 Error **errp) 597 { 598 MigrationState *s = migrate_get_current(); 599 MigrationCapabilityStatusList *cap; 600 bool old_postcopy_cap = migrate_postcopy_ram(); 601 602 if (migration_is_setup_or_active(s->state)) { 603 error_setg(errp, QERR_MIGRATION_ACTIVE); 604 return; 605 } 606 607 for (cap = params; cap; cap = cap->next) { 608 #ifndef CONFIG_LIVE_BLOCK_MIGRATION 609 if (cap->value->capability == MIGRATION_CAPABILITY_BLOCK 610 && cap->value->state) { 611 error_setg(errp, "QEMU compiled without old-style (blk/-b, inc/-i) " 612 "block migration"); 613 error_append_hint(errp, "Use drive_mirror+NBD instead.\n"); 614 continue; 615 } 616 #endif 617 if (cap->value->capability == MIGRATION_CAPABILITY_X_COLO) { 618 if (!colo_supported()) { 619 error_setg(errp, "COLO is not currently supported, please" 620 " configure with --enable-colo option in order to" 621 " support COLO feature"); 622 continue; 623 } 624 } 625 s->enabled_capabilities[cap->value->capability] = cap->value->state; 626 } 627 628 if (migrate_postcopy_ram()) { 629 if (migrate_use_compression()) { 630 /* The decompression threads asynchronously write into RAM 631 * rather than use the atomic copies needed to avoid 632 * userfaulting. It should be possible to fix the decompression 633 * threads for compatibility in future. 634 */ 635 error_report("Postcopy is not currently compatible with " 636 "compression"); 637 s->enabled_capabilities[MIGRATION_CAPABILITY_POSTCOPY_RAM] = 638 false; 639 } 640 /* This check is reasonably expensive, so only when it's being 641 * set the first time, also it's only the destination that needs 642 * special support. 643 */ 644 if (!old_postcopy_cap && runstate_check(RUN_STATE_INMIGRATE) && 645 !postcopy_ram_supported_by_host()) { 646 /* postcopy_ram_supported_by_host will have emitted a more 647 * detailed message 648 */ 649 error_report("Postcopy is not supported"); 650 s->enabled_capabilities[MIGRATION_CAPABILITY_POSTCOPY_RAM] = 651 false; 652 } 653 } 654 } 655 656 void qmp_migrate_set_parameters(MigrationParameters *params, Error **errp) 657 { 658 MigrationState *s = migrate_get_current(); 659 660 if (params->has_compress_level && 661 (params->compress_level < 0 || params->compress_level > 9)) { 662 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "compress_level", 663 "is invalid, it should be in the range of 0 to 9"); 664 return; 665 } 666 if (params->has_compress_threads && 667 (params->compress_threads < 1 || params->compress_threads > 255)) { 668 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, 669 "compress_threads", 670 "is invalid, it should be in the range of 1 to 255"); 671 return; 672 } 673 if (params->has_decompress_threads && 674 (params->decompress_threads < 1 || params->decompress_threads > 255)) { 675 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, 676 "decompress_threads", 677 "is invalid, it should be in the range of 1 to 255"); 678 return; 679 } 680 if (params->has_cpu_throttle_initial && 681 (params->cpu_throttle_initial < 1 || 682 params->cpu_throttle_initial > 99)) { 683 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, 684 "cpu_throttle_initial", 685 "an integer in the range of 1 to 99"); 686 return; 687 } 688 if (params->has_cpu_throttle_increment && 689 (params->cpu_throttle_increment < 1 || 690 params->cpu_throttle_increment > 99)) { 691 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, 692 "cpu_throttle_increment", 693 "an integer in the range of 1 to 99"); 694 return; 695 } 696 if (params->has_max_bandwidth && 697 (params->max_bandwidth < 0 || params->max_bandwidth > SIZE_MAX)) { 698 error_setg(errp, "Parameter 'max_bandwidth' expects an integer in the" 699 " range of 0 to %zu bytes/second", SIZE_MAX); 700 return; 701 } 702 if (params->has_downtime_limit && 703 (params->downtime_limit < 0 || 704 params->downtime_limit > MAX_MIGRATE_DOWNTIME)) { 705 error_setg(errp, "Parameter 'downtime_limit' expects an integer in " 706 "the range of 0 to %d milliseconds", 707 MAX_MIGRATE_DOWNTIME); 708 return; 709 } 710 if (params->has_x_checkpoint_delay && (params->x_checkpoint_delay < 0)) { 711 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, 712 "x_checkpoint_delay", 713 "is invalid, it should be positive"); 714 } 715 716 if (params->has_compress_level) { 717 s->parameters.compress_level = params->compress_level; 718 } 719 if (params->has_compress_threads) { 720 s->parameters.compress_threads = params->compress_threads; 721 } 722 if (params->has_decompress_threads) { 723 s->parameters.decompress_threads = params->decompress_threads; 724 } 725 if (params->has_cpu_throttle_initial) { 726 s->parameters.cpu_throttle_initial = params->cpu_throttle_initial; 727 } 728 if (params->has_cpu_throttle_increment) { 729 s->parameters.cpu_throttle_increment = params->cpu_throttle_increment; 730 } 731 if (params->has_tls_creds) { 732 g_free(s->parameters.tls_creds); 733 s->parameters.tls_creds = g_strdup(params->tls_creds); 734 } 735 if (params->has_tls_hostname) { 736 g_free(s->parameters.tls_hostname); 737 s->parameters.tls_hostname = g_strdup(params->tls_hostname); 738 } 739 if (params->has_max_bandwidth) { 740 s->parameters.max_bandwidth = params->max_bandwidth; 741 if (s->to_dst_file) { 742 qemu_file_set_rate_limit(s->to_dst_file, 743 s->parameters.max_bandwidth / XFER_LIMIT_RATIO); 744 } 745 } 746 if (params->has_downtime_limit) { 747 s->parameters.downtime_limit = params->downtime_limit; 748 } 749 750 if (params->has_x_checkpoint_delay) { 751 s->parameters.x_checkpoint_delay = params->x_checkpoint_delay; 752 if (migration_in_colo_state()) { 753 colo_checkpoint_notify(s); 754 } 755 } 756 if (params->has_block_incremental) { 757 s->parameters.block_incremental = params->block_incremental; 758 } 759 } 760 761 762 void qmp_migrate_start_postcopy(Error **errp) 763 { 764 MigrationState *s = migrate_get_current(); 765 766 if (!migrate_postcopy_ram()) { 767 error_setg(errp, "Enable postcopy with migrate_set_capability before" 768 " the start of migration"); 769 return; 770 } 771 772 if (s->state == MIGRATION_STATUS_NONE) { 773 error_setg(errp, "Postcopy must be started after migration has been" 774 " started"); 775 return; 776 } 777 /* 778 * we don't error if migration has finished since that would be racy 779 * with issuing this command. 780 */ 781 atomic_set(&s->start_postcopy, true); 782 } 783 784 /* shared migration helpers */ 785 786 void migrate_set_state(int *state, int old_state, int new_state) 787 { 788 if (atomic_cmpxchg(state, old_state, new_state) == old_state) { 789 trace_migrate_set_state(new_state); 790 migrate_generate_event(new_state); 791 } 792 } 793 794 void migrate_set_block_enabled(bool value, Error **errp) 795 { 796 MigrationCapabilityStatusList *cap; 797 798 cap = g_new0(MigrationCapabilityStatusList, 1); 799 cap->value = g_new0(MigrationCapabilityStatus, 1); 800 cap->value->capability = MIGRATION_CAPABILITY_BLOCK; 801 cap->value->state = value; 802 qmp_migrate_set_capabilities(cap, errp); 803 qapi_free_MigrationCapabilityStatusList(cap); 804 } 805 806 static void migrate_set_block_incremental(MigrationState *s, bool value) 807 { 808 s->parameters.block_incremental = value; 809 } 810 811 static void block_cleanup_parameters(MigrationState *s) 812 { 813 if (s->must_remove_block_options) { 814 /* setting to false can never fail */ 815 migrate_set_block_enabled(false, &error_abort); 816 migrate_set_block_incremental(s, false); 817 s->must_remove_block_options = false; 818 } 819 } 820 821 static void migrate_fd_cleanup(void *opaque) 822 { 823 MigrationState *s = opaque; 824 825 qemu_bh_delete(s->cleanup_bh); 826 s->cleanup_bh = NULL; 827 828 if (s->to_dst_file) { 829 trace_migrate_fd_cleanup(); 830 qemu_mutex_unlock_iothread(); 831 if (s->migration_thread_running) { 832 qemu_thread_join(&s->thread); 833 s->migration_thread_running = false; 834 } 835 qemu_mutex_lock_iothread(); 836 837 migrate_compress_threads_join(); 838 qemu_fclose(s->to_dst_file); 839 s->to_dst_file = NULL; 840 } 841 842 assert((s->state != MIGRATION_STATUS_ACTIVE) && 843 (s->state != MIGRATION_STATUS_POSTCOPY_ACTIVE)); 844 845 if (s->state == MIGRATION_STATUS_CANCELLING) { 846 migrate_set_state(&s->state, MIGRATION_STATUS_CANCELLING, 847 MIGRATION_STATUS_CANCELLED); 848 } 849 850 notifier_list_notify(&migration_state_notifiers, s); 851 block_cleanup_parameters(s); 852 } 853 854 void migrate_fd_error(MigrationState *s, const Error *error) 855 { 856 trace_migrate_fd_error(error_get_pretty(error)); 857 assert(s->to_dst_file == NULL); 858 migrate_set_state(&s->state, MIGRATION_STATUS_SETUP, 859 MIGRATION_STATUS_FAILED); 860 if (!s->error) { 861 s->error = error_copy(error); 862 } 863 notifier_list_notify(&migration_state_notifiers, s); 864 block_cleanup_parameters(s); 865 } 866 867 static void migrate_fd_cancel(MigrationState *s) 868 { 869 int old_state ; 870 QEMUFile *f = migrate_get_current()->to_dst_file; 871 trace_migrate_fd_cancel(); 872 873 if (s->rp_state.from_dst_file) { 874 /* shutdown the rp socket, so causing the rp thread to shutdown */ 875 qemu_file_shutdown(s->rp_state.from_dst_file); 876 } 877 878 do { 879 old_state = s->state; 880 if (!migration_is_setup_or_active(old_state)) { 881 break; 882 } 883 migrate_set_state(&s->state, old_state, MIGRATION_STATUS_CANCELLING); 884 } while (s->state != MIGRATION_STATUS_CANCELLING); 885 886 /* 887 * If we're unlucky the migration code might be stuck somewhere in a 888 * send/write while the network has failed and is waiting to timeout; 889 * if we've got shutdown(2) available then we can force it to quit. 890 * The outgoing qemu file gets closed in migrate_fd_cleanup that is 891 * called in a bh, so there is no race against this cancel. 892 */ 893 if (s->state == MIGRATION_STATUS_CANCELLING && f) { 894 qemu_file_shutdown(f); 895 } 896 if (s->state == MIGRATION_STATUS_CANCELLING && s->block_inactive) { 897 Error *local_err = NULL; 898 899 bdrv_invalidate_cache_all(&local_err); 900 if (local_err) { 901 error_report_err(local_err); 902 } else { 903 s->block_inactive = false; 904 } 905 } 906 block_cleanup_parameters(s); 907 } 908 909 void add_migration_state_change_notifier(Notifier *notify) 910 { 911 notifier_list_add(&migration_state_notifiers, notify); 912 } 913 914 void remove_migration_state_change_notifier(Notifier *notify) 915 { 916 notifier_remove(notify); 917 } 918 919 bool migration_in_setup(MigrationState *s) 920 { 921 return s->state == MIGRATION_STATUS_SETUP; 922 } 923 924 bool migration_has_finished(MigrationState *s) 925 { 926 return s->state == MIGRATION_STATUS_COMPLETED; 927 } 928 929 bool migration_has_failed(MigrationState *s) 930 { 931 return (s->state == MIGRATION_STATUS_CANCELLED || 932 s->state == MIGRATION_STATUS_FAILED); 933 } 934 935 bool migration_in_postcopy(void) 936 { 937 MigrationState *s = migrate_get_current(); 938 939 return (s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE); 940 } 941 942 bool migration_in_postcopy_after_devices(MigrationState *s) 943 { 944 return migration_in_postcopy() && s->postcopy_after_devices; 945 } 946 947 bool migration_is_idle(void) 948 { 949 MigrationState *s = migrate_get_current(); 950 951 switch (s->state) { 952 case MIGRATION_STATUS_NONE: 953 case MIGRATION_STATUS_CANCELLED: 954 case MIGRATION_STATUS_COMPLETED: 955 case MIGRATION_STATUS_FAILED: 956 return true; 957 case MIGRATION_STATUS_SETUP: 958 case MIGRATION_STATUS_CANCELLING: 959 case MIGRATION_STATUS_ACTIVE: 960 case MIGRATION_STATUS_POSTCOPY_ACTIVE: 961 case MIGRATION_STATUS_COLO: 962 return false; 963 case MIGRATION_STATUS__MAX: 964 g_assert_not_reached(); 965 } 966 967 return false; 968 } 969 970 MigrationState *migrate_init(void) 971 { 972 MigrationState *s = migrate_get_current(); 973 974 /* 975 * Reinitialise all migration state, except 976 * parameters/capabilities that the user set, and 977 * locks. 978 */ 979 s->bytes_xfer = 0; 980 s->xfer_limit = 0; 981 s->cleanup_bh = 0; 982 s->to_dst_file = NULL; 983 s->state = MIGRATION_STATUS_NONE; 984 s->rp_state.from_dst_file = NULL; 985 s->rp_state.error = false; 986 s->mbps = 0.0; 987 s->downtime = 0; 988 s->expected_downtime = 0; 989 s->setup_time = 0; 990 s->start_postcopy = false; 991 s->postcopy_after_devices = false; 992 s->migration_thread_running = false; 993 error_free(s->error); 994 s->error = NULL; 995 996 migrate_set_state(&s->state, MIGRATION_STATUS_NONE, MIGRATION_STATUS_SETUP); 997 998 s->total_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); 999 return s; 1000 } 1001 1002 static GSList *migration_blockers; 1003 1004 int migrate_add_blocker(Error *reason, Error **errp) 1005 { 1006 if (only_migratable) { 1007 error_propagate(errp, error_copy(reason)); 1008 error_prepend(errp, "disallowing migration blocker " 1009 "(--only_migratable) for: "); 1010 return -EACCES; 1011 } 1012 1013 if (migration_is_idle()) { 1014 migration_blockers = g_slist_prepend(migration_blockers, reason); 1015 return 0; 1016 } 1017 1018 error_propagate(errp, error_copy(reason)); 1019 error_prepend(errp, "disallowing migration blocker (migration in " 1020 "progress) for: "); 1021 return -EBUSY; 1022 } 1023 1024 void migrate_del_blocker(Error *reason) 1025 { 1026 migration_blockers = g_slist_remove(migration_blockers, reason); 1027 } 1028 1029 void qmp_migrate_incoming(const char *uri, Error **errp) 1030 { 1031 Error *local_err = NULL; 1032 static bool once = true; 1033 1034 if (!deferred_incoming) { 1035 error_setg(errp, "For use with '-incoming defer'"); 1036 return; 1037 } 1038 if (!once) { 1039 error_setg(errp, "The incoming migration has already been started"); 1040 } 1041 1042 qemu_start_incoming_migration(uri, &local_err); 1043 1044 if (local_err) { 1045 error_propagate(errp, local_err); 1046 return; 1047 } 1048 1049 once = false; 1050 } 1051 1052 bool migration_is_blocked(Error **errp) 1053 { 1054 if (qemu_savevm_state_blocked(errp)) { 1055 return true; 1056 } 1057 1058 if (migration_blockers) { 1059 error_propagate(errp, error_copy(migration_blockers->data)); 1060 return true; 1061 } 1062 1063 return false; 1064 } 1065 1066 void qmp_migrate(const char *uri, bool has_blk, bool blk, 1067 bool has_inc, bool inc, bool has_detach, bool detach, 1068 Error **errp) 1069 { 1070 Error *local_err = NULL; 1071 MigrationState *s = migrate_get_current(); 1072 const char *p; 1073 1074 if (migration_is_setup_or_active(s->state) || 1075 s->state == MIGRATION_STATUS_CANCELLING || 1076 s->state == MIGRATION_STATUS_COLO) { 1077 error_setg(errp, QERR_MIGRATION_ACTIVE); 1078 return; 1079 } 1080 if (runstate_check(RUN_STATE_INMIGRATE)) { 1081 error_setg(errp, "Guest is waiting for an incoming migration"); 1082 return; 1083 } 1084 1085 if (migration_is_blocked(errp)) { 1086 return; 1087 } 1088 1089 if ((has_blk && blk) || (has_inc && inc)) { 1090 if (migrate_use_block() || migrate_use_block_incremental()) { 1091 error_setg(errp, "Command options are incompatible with " 1092 "current migration capabilities"); 1093 return; 1094 } 1095 migrate_set_block_enabled(true, &local_err); 1096 if (local_err) { 1097 error_propagate(errp, local_err); 1098 return; 1099 } 1100 s->must_remove_block_options = true; 1101 } 1102 1103 if (has_inc && inc) { 1104 migrate_set_block_incremental(s, true); 1105 } 1106 1107 s = migrate_init(); 1108 1109 if (strstart(uri, "tcp:", &p)) { 1110 tcp_start_outgoing_migration(s, p, &local_err); 1111 #ifdef CONFIG_RDMA 1112 } else if (strstart(uri, "rdma:", &p)) { 1113 rdma_start_outgoing_migration(s, p, &local_err); 1114 #endif 1115 } else if (strstart(uri, "exec:", &p)) { 1116 exec_start_outgoing_migration(s, p, &local_err); 1117 } else if (strstart(uri, "unix:", &p)) { 1118 unix_start_outgoing_migration(s, p, &local_err); 1119 } else if (strstart(uri, "fd:", &p)) { 1120 fd_start_outgoing_migration(s, p, &local_err); 1121 } else { 1122 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "uri", 1123 "a valid migration protocol"); 1124 migrate_set_state(&s->state, MIGRATION_STATUS_SETUP, 1125 MIGRATION_STATUS_FAILED); 1126 return; 1127 } 1128 1129 if (local_err) { 1130 migrate_fd_error(s, local_err); 1131 error_propagate(errp, local_err); 1132 return; 1133 } 1134 } 1135 1136 void qmp_migrate_cancel(Error **errp) 1137 { 1138 migrate_fd_cancel(migrate_get_current()); 1139 } 1140 1141 void qmp_migrate_set_cache_size(int64_t value, Error **errp) 1142 { 1143 MigrationState *s = migrate_get_current(); 1144 int64_t new_size; 1145 1146 /* Check for truncation */ 1147 if (value != (size_t)value) { 1148 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cache size", 1149 "exceeding address space"); 1150 return; 1151 } 1152 1153 /* Cache should not be larger than guest ram size */ 1154 if (value > ram_bytes_total()) { 1155 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cache size", 1156 "exceeds guest ram size "); 1157 return; 1158 } 1159 1160 new_size = xbzrle_cache_resize(value); 1161 if (new_size < 0) { 1162 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cache size", 1163 "is smaller than page size"); 1164 return; 1165 } 1166 1167 s->xbzrle_cache_size = new_size; 1168 } 1169 1170 int64_t qmp_query_migrate_cache_size(Error **errp) 1171 { 1172 return migrate_xbzrle_cache_size(); 1173 } 1174 1175 void qmp_migrate_set_speed(int64_t value, Error **errp) 1176 { 1177 MigrationParameters p = { 1178 .has_max_bandwidth = true, 1179 .max_bandwidth = value, 1180 }; 1181 1182 qmp_migrate_set_parameters(&p, errp); 1183 } 1184 1185 void qmp_migrate_set_downtime(double value, Error **errp) 1186 { 1187 if (value < 0 || value > MAX_MIGRATE_DOWNTIME_SECONDS) { 1188 error_setg(errp, "Parameter 'downtime_limit' expects an integer in " 1189 "the range of 0 to %d seconds", 1190 MAX_MIGRATE_DOWNTIME_SECONDS); 1191 return; 1192 } 1193 1194 value *= 1000; /* Convert to milliseconds */ 1195 value = MAX(0, MIN(INT64_MAX, value)); 1196 1197 MigrationParameters p = { 1198 .has_downtime_limit = true, 1199 .downtime_limit = value, 1200 }; 1201 1202 qmp_migrate_set_parameters(&p, errp); 1203 } 1204 1205 bool migrate_release_ram(void) 1206 { 1207 MigrationState *s; 1208 1209 s = migrate_get_current(); 1210 1211 return s->enabled_capabilities[MIGRATION_CAPABILITY_RELEASE_RAM]; 1212 } 1213 1214 bool migrate_postcopy_ram(void) 1215 { 1216 MigrationState *s; 1217 1218 s = migrate_get_current(); 1219 1220 return s->enabled_capabilities[MIGRATION_CAPABILITY_POSTCOPY_RAM]; 1221 } 1222 1223 bool migrate_auto_converge(void) 1224 { 1225 MigrationState *s; 1226 1227 s = migrate_get_current(); 1228 1229 return s->enabled_capabilities[MIGRATION_CAPABILITY_AUTO_CONVERGE]; 1230 } 1231 1232 bool migrate_zero_blocks(void) 1233 { 1234 MigrationState *s; 1235 1236 s = migrate_get_current(); 1237 1238 return s->enabled_capabilities[MIGRATION_CAPABILITY_ZERO_BLOCKS]; 1239 } 1240 1241 bool migrate_use_compression(void) 1242 { 1243 MigrationState *s; 1244 1245 s = migrate_get_current(); 1246 1247 return s->enabled_capabilities[MIGRATION_CAPABILITY_COMPRESS]; 1248 } 1249 1250 int migrate_compress_level(void) 1251 { 1252 MigrationState *s; 1253 1254 s = migrate_get_current(); 1255 1256 return s->parameters.compress_level; 1257 } 1258 1259 int migrate_compress_threads(void) 1260 { 1261 MigrationState *s; 1262 1263 s = migrate_get_current(); 1264 1265 return s->parameters.compress_threads; 1266 } 1267 1268 int migrate_decompress_threads(void) 1269 { 1270 MigrationState *s; 1271 1272 s = migrate_get_current(); 1273 1274 return s->parameters.decompress_threads; 1275 } 1276 1277 bool migrate_use_events(void) 1278 { 1279 MigrationState *s; 1280 1281 s = migrate_get_current(); 1282 1283 return s->enabled_capabilities[MIGRATION_CAPABILITY_EVENTS]; 1284 } 1285 1286 int migrate_use_xbzrle(void) 1287 { 1288 MigrationState *s; 1289 1290 s = migrate_get_current(); 1291 1292 return s->enabled_capabilities[MIGRATION_CAPABILITY_XBZRLE]; 1293 } 1294 1295 int64_t migrate_xbzrle_cache_size(void) 1296 { 1297 MigrationState *s; 1298 1299 s = migrate_get_current(); 1300 1301 return s->xbzrle_cache_size; 1302 } 1303 1304 bool migrate_use_block(void) 1305 { 1306 MigrationState *s; 1307 1308 s = migrate_get_current(); 1309 1310 return s->enabled_capabilities[MIGRATION_CAPABILITY_BLOCK]; 1311 } 1312 1313 bool migrate_use_block_incremental(void) 1314 { 1315 MigrationState *s; 1316 1317 s = migrate_get_current(); 1318 1319 return s->parameters.block_incremental; 1320 } 1321 1322 /* migration thread support */ 1323 /* 1324 * Something bad happened to the RP stream, mark an error 1325 * The caller shall print or trace something to indicate why 1326 */ 1327 static void mark_source_rp_bad(MigrationState *s) 1328 { 1329 s->rp_state.error = true; 1330 } 1331 1332 static struct rp_cmd_args { 1333 ssize_t len; /* -1 = variable */ 1334 const char *name; 1335 } rp_cmd_args[] = { 1336 [MIG_RP_MSG_INVALID] = { .len = -1, .name = "INVALID" }, 1337 [MIG_RP_MSG_SHUT] = { .len = 4, .name = "SHUT" }, 1338 [MIG_RP_MSG_PONG] = { .len = 4, .name = "PONG" }, 1339 [MIG_RP_MSG_REQ_PAGES] = { .len = 12, .name = "REQ_PAGES" }, 1340 [MIG_RP_MSG_REQ_PAGES_ID] = { .len = -1, .name = "REQ_PAGES_ID" }, 1341 [MIG_RP_MSG_MAX] = { .len = -1, .name = "MAX" }, 1342 }; 1343 1344 /* 1345 * Process a request for pages received on the return path, 1346 * We're allowed to send more than requested (e.g. to round to our page size) 1347 * and we don't need to send pages that have already been sent. 1348 */ 1349 static void migrate_handle_rp_req_pages(MigrationState *ms, const char* rbname, 1350 ram_addr_t start, size_t len) 1351 { 1352 long our_host_ps = getpagesize(); 1353 1354 trace_migrate_handle_rp_req_pages(rbname, start, len); 1355 1356 /* 1357 * Since we currently insist on matching page sizes, just sanity check 1358 * we're being asked for whole host pages. 1359 */ 1360 if (start & (our_host_ps-1) || 1361 (len & (our_host_ps-1))) { 1362 error_report("%s: Misaligned page request, start: " RAM_ADDR_FMT 1363 " len: %zd", __func__, start, len); 1364 mark_source_rp_bad(ms); 1365 return; 1366 } 1367 1368 if (ram_save_queue_pages(rbname, start, len)) { 1369 mark_source_rp_bad(ms); 1370 } 1371 } 1372 1373 /* 1374 * Handles messages sent on the return path towards the source VM 1375 * 1376 */ 1377 static void *source_return_path_thread(void *opaque) 1378 { 1379 MigrationState *ms = opaque; 1380 QEMUFile *rp = ms->rp_state.from_dst_file; 1381 uint16_t header_len, header_type; 1382 uint8_t buf[512]; 1383 uint32_t tmp32, sibling_error; 1384 ram_addr_t start = 0; /* =0 to silence warning */ 1385 size_t len = 0, expected_len; 1386 int res; 1387 1388 trace_source_return_path_thread_entry(); 1389 while (!ms->rp_state.error && !qemu_file_get_error(rp) && 1390 migration_is_setup_or_active(ms->state)) { 1391 trace_source_return_path_thread_loop_top(); 1392 header_type = qemu_get_be16(rp); 1393 header_len = qemu_get_be16(rp); 1394 1395 if (header_type >= MIG_RP_MSG_MAX || 1396 header_type == MIG_RP_MSG_INVALID) { 1397 error_report("RP: Received invalid message 0x%04x length 0x%04x", 1398 header_type, header_len); 1399 mark_source_rp_bad(ms); 1400 goto out; 1401 } 1402 1403 if ((rp_cmd_args[header_type].len != -1 && 1404 header_len != rp_cmd_args[header_type].len) || 1405 header_len > sizeof(buf)) { 1406 error_report("RP: Received '%s' message (0x%04x) with" 1407 "incorrect length %d expecting %zu", 1408 rp_cmd_args[header_type].name, header_type, header_len, 1409 (size_t)rp_cmd_args[header_type].len); 1410 mark_source_rp_bad(ms); 1411 goto out; 1412 } 1413 1414 /* We know we've got a valid header by this point */ 1415 res = qemu_get_buffer(rp, buf, header_len); 1416 if (res != header_len) { 1417 error_report("RP: Failed reading data for message 0x%04x" 1418 " read %d expected %d", 1419 header_type, res, header_len); 1420 mark_source_rp_bad(ms); 1421 goto out; 1422 } 1423 1424 /* OK, we have the message and the data */ 1425 switch (header_type) { 1426 case MIG_RP_MSG_SHUT: 1427 sibling_error = ldl_be_p(buf); 1428 trace_source_return_path_thread_shut(sibling_error); 1429 if (sibling_error) { 1430 error_report("RP: Sibling indicated error %d", sibling_error); 1431 mark_source_rp_bad(ms); 1432 } 1433 /* 1434 * We'll let the main thread deal with closing the RP 1435 * we could do a shutdown(2) on it, but we're the only user 1436 * anyway, so there's nothing gained. 1437 */ 1438 goto out; 1439 1440 case MIG_RP_MSG_PONG: 1441 tmp32 = ldl_be_p(buf); 1442 trace_source_return_path_thread_pong(tmp32); 1443 break; 1444 1445 case MIG_RP_MSG_REQ_PAGES: 1446 start = ldq_be_p(buf); 1447 len = ldl_be_p(buf + 8); 1448 migrate_handle_rp_req_pages(ms, NULL, start, len); 1449 break; 1450 1451 case MIG_RP_MSG_REQ_PAGES_ID: 1452 expected_len = 12 + 1; /* header + termination */ 1453 1454 if (header_len >= expected_len) { 1455 start = ldq_be_p(buf); 1456 len = ldl_be_p(buf + 8); 1457 /* Now we expect an idstr */ 1458 tmp32 = buf[12]; /* Length of the following idstr */ 1459 buf[13 + tmp32] = '\0'; 1460 expected_len += tmp32; 1461 } 1462 if (header_len != expected_len) { 1463 error_report("RP: Req_Page_id with length %d expecting %zd", 1464 header_len, expected_len); 1465 mark_source_rp_bad(ms); 1466 goto out; 1467 } 1468 migrate_handle_rp_req_pages(ms, (char *)&buf[13], start, len); 1469 break; 1470 1471 default: 1472 break; 1473 } 1474 } 1475 if (qemu_file_get_error(rp)) { 1476 trace_source_return_path_thread_bad_end(); 1477 mark_source_rp_bad(ms); 1478 } 1479 1480 trace_source_return_path_thread_end(); 1481 out: 1482 ms->rp_state.from_dst_file = NULL; 1483 qemu_fclose(rp); 1484 return NULL; 1485 } 1486 1487 static int open_return_path_on_source(MigrationState *ms) 1488 { 1489 1490 ms->rp_state.from_dst_file = qemu_file_get_return_path(ms->to_dst_file); 1491 if (!ms->rp_state.from_dst_file) { 1492 return -1; 1493 } 1494 1495 trace_open_return_path_on_source(); 1496 qemu_thread_create(&ms->rp_state.rp_thread, "return path", 1497 source_return_path_thread, ms, QEMU_THREAD_JOINABLE); 1498 1499 trace_open_return_path_on_source_continue(); 1500 1501 return 0; 1502 } 1503 1504 /* Returns 0 if the RP was ok, otherwise there was an error on the RP */ 1505 static int await_return_path_close_on_source(MigrationState *ms) 1506 { 1507 /* 1508 * If this is a normal exit then the destination will send a SHUT and the 1509 * rp_thread will exit, however if there's an error we need to cause 1510 * it to exit. 1511 */ 1512 if (qemu_file_get_error(ms->to_dst_file) && ms->rp_state.from_dst_file) { 1513 /* 1514 * shutdown(2), if we have it, will cause it to unblock if it's stuck 1515 * waiting for the destination. 1516 */ 1517 qemu_file_shutdown(ms->rp_state.from_dst_file); 1518 mark_source_rp_bad(ms); 1519 } 1520 trace_await_return_path_close_on_source_joining(); 1521 qemu_thread_join(&ms->rp_state.rp_thread); 1522 trace_await_return_path_close_on_source_close(); 1523 return ms->rp_state.error; 1524 } 1525 1526 /* 1527 * Switch from normal iteration to postcopy 1528 * Returns non-0 on error 1529 */ 1530 static int postcopy_start(MigrationState *ms, bool *old_vm_running) 1531 { 1532 int ret; 1533 QIOChannelBuffer *bioc; 1534 QEMUFile *fb; 1535 int64_t time_at_stop = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); 1536 bool restart_block = false; 1537 migrate_set_state(&ms->state, MIGRATION_STATUS_ACTIVE, 1538 MIGRATION_STATUS_POSTCOPY_ACTIVE); 1539 1540 trace_postcopy_start(); 1541 qemu_mutex_lock_iothread(); 1542 trace_postcopy_start_set_run(); 1543 1544 qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER); 1545 *old_vm_running = runstate_is_running(); 1546 global_state_store(); 1547 ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE); 1548 if (ret < 0) { 1549 goto fail; 1550 } 1551 1552 ret = bdrv_inactivate_all(); 1553 if (ret < 0) { 1554 goto fail; 1555 } 1556 restart_block = true; 1557 1558 /* 1559 * Cause any non-postcopiable, but iterative devices to 1560 * send out their final data. 1561 */ 1562 qemu_savevm_state_complete_precopy(ms->to_dst_file, true); 1563 1564 /* 1565 * in Finish migrate and with the io-lock held everything should 1566 * be quiet, but we've potentially still got dirty pages and we 1567 * need to tell the destination to throw any pages it's already received 1568 * that are dirty 1569 */ 1570 if (ram_postcopy_send_discard_bitmap(ms)) { 1571 error_report("postcopy send discard bitmap failed"); 1572 goto fail; 1573 } 1574 1575 /* 1576 * send rest of state - note things that are doing postcopy 1577 * will notice we're in POSTCOPY_ACTIVE and not actually 1578 * wrap their state up here 1579 */ 1580 qemu_file_set_rate_limit(ms->to_dst_file, INT64_MAX); 1581 /* Ping just for debugging, helps line traces up */ 1582 qemu_savevm_send_ping(ms->to_dst_file, 2); 1583 1584 /* 1585 * While loading the device state we may trigger page transfer 1586 * requests and the fd must be free to process those, and thus 1587 * the destination must read the whole device state off the fd before 1588 * it starts processing it. Unfortunately the ad-hoc migration format 1589 * doesn't allow the destination to know the size to read without fully 1590 * parsing it through each devices load-state code (especially the open 1591 * coded devices that use get/put). 1592 * So we wrap the device state up in a package with a length at the start; 1593 * to do this we use a qemu_buf to hold the whole of the device state. 1594 */ 1595 bioc = qio_channel_buffer_new(4096); 1596 qio_channel_set_name(QIO_CHANNEL(bioc), "migration-postcopy-buffer"); 1597 fb = qemu_fopen_channel_output(QIO_CHANNEL(bioc)); 1598 object_unref(OBJECT(bioc)); 1599 1600 /* 1601 * Make sure the receiver can get incoming pages before we send the rest 1602 * of the state 1603 */ 1604 qemu_savevm_send_postcopy_listen(fb); 1605 1606 qemu_savevm_state_complete_precopy(fb, false); 1607 qemu_savevm_send_ping(fb, 3); 1608 1609 qemu_savevm_send_postcopy_run(fb); 1610 1611 /* <><> end of stuff going into the package */ 1612 1613 /* Last point of recovery; as soon as we send the package the destination 1614 * can open devices and potentially start running. 1615 * Lets just check again we've not got any errors. 1616 */ 1617 ret = qemu_file_get_error(ms->to_dst_file); 1618 if (ret) { 1619 error_report("postcopy_start: Migration stream errored (pre package)"); 1620 goto fail_closefb; 1621 } 1622 1623 restart_block = false; 1624 1625 /* Now send that blob */ 1626 if (qemu_savevm_send_packaged(ms->to_dst_file, bioc->data, bioc->usage)) { 1627 goto fail_closefb; 1628 } 1629 qemu_fclose(fb); 1630 1631 /* Send a notify to give a chance for anything that needs to happen 1632 * at the transition to postcopy and after the device state; in particular 1633 * spice needs to trigger a transition now 1634 */ 1635 ms->postcopy_after_devices = true; 1636 notifier_list_notify(&migration_state_notifiers, ms); 1637 1638 ms->downtime = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) - time_at_stop; 1639 1640 qemu_mutex_unlock_iothread(); 1641 1642 /* 1643 * Although this ping is just for debug, it could potentially be 1644 * used for getting a better measurement of downtime at the source. 1645 */ 1646 qemu_savevm_send_ping(ms->to_dst_file, 4); 1647 1648 if (migrate_release_ram()) { 1649 ram_postcopy_migrated_memory_release(ms); 1650 } 1651 1652 ret = qemu_file_get_error(ms->to_dst_file); 1653 if (ret) { 1654 error_report("postcopy_start: Migration stream errored"); 1655 migrate_set_state(&ms->state, MIGRATION_STATUS_POSTCOPY_ACTIVE, 1656 MIGRATION_STATUS_FAILED); 1657 } 1658 1659 return ret; 1660 1661 fail_closefb: 1662 qemu_fclose(fb); 1663 fail: 1664 migrate_set_state(&ms->state, MIGRATION_STATUS_POSTCOPY_ACTIVE, 1665 MIGRATION_STATUS_FAILED); 1666 if (restart_block) { 1667 /* A failure happened early enough that we know the destination hasn't 1668 * accessed block devices, so we're safe to recover. 1669 */ 1670 Error *local_err = NULL; 1671 1672 bdrv_invalidate_cache_all(&local_err); 1673 if (local_err) { 1674 error_report_err(local_err); 1675 } 1676 } 1677 qemu_mutex_unlock_iothread(); 1678 return -1; 1679 } 1680 1681 /** 1682 * migration_completion: Used by migration_thread when there's not much left. 1683 * The caller 'breaks' the loop when this returns. 1684 * 1685 * @s: Current migration state 1686 * @current_active_state: The migration state we expect to be in 1687 * @*old_vm_running: Pointer to old_vm_running flag 1688 * @*start_time: Pointer to time to update 1689 */ 1690 static void migration_completion(MigrationState *s, int current_active_state, 1691 bool *old_vm_running, 1692 int64_t *start_time) 1693 { 1694 int ret; 1695 1696 if (s->state == MIGRATION_STATUS_ACTIVE) { 1697 qemu_mutex_lock_iothread(); 1698 *start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); 1699 qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER); 1700 *old_vm_running = runstate_is_running(); 1701 ret = global_state_store(); 1702 1703 if (!ret) { 1704 ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE); 1705 if (ret >= 0) { 1706 qemu_file_set_rate_limit(s->to_dst_file, INT64_MAX); 1707 qemu_savevm_state_complete_precopy(s->to_dst_file, false); 1708 } 1709 /* 1710 * Don't mark the image with BDRV_O_INACTIVE flag if 1711 * we will go into COLO stage later. 1712 */ 1713 if (ret >= 0 && !migrate_colo_enabled()) { 1714 ret = bdrv_inactivate_all(); 1715 if (ret >= 0) { 1716 s->block_inactive = true; 1717 } 1718 } 1719 } 1720 qemu_mutex_unlock_iothread(); 1721 1722 if (ret < 0) { 1723 goto fail; 1724 } 1725 } else if (s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE) { 1726 trace_migration_completion_postcopy_end(); 1727 1728 qemu_savevm_state_complete_postcopy(s->to_dst_file); 1729 trace_migration_completion_postcopy_end_after_complete(); 1730 } 1731 1732 /* 1733 * If rp was opened we must clean up the thread before 1734 * cleaning everything else up (since if there are no failures 1735 * it will wait for the destination to send it's status in 1736 * a SHUT command). 1737 */ 1738 if (s->rp_state.from_dst_file) { 1739 int rp_error; 1740 trace_migration_return_path_end_before(); 1741 rp_error = await_return_path_close_on_source(s); 1742 trace_migration_return_path_end_after(rp_error); 1743 if (rp_error) { 1744 goto fail_invalidate; 1745 } 1746 } 1747 1748 if (qemu_file_get_error(s->to_dst_file)) { 1749 trace_migration_completion_file_err(); 1750 goto fail_invalidate; 1751 } 1752 1753 if (!migrate_colo_enabled()) { 1754 migrate_set_state(&s->state, current_active_state, 1755 MIGRATION_STATUS_COMPLETED); 1756 } 1757 1758 return; 1759 1760 fail_invalidate: 1761 /* If not doing postcopy, vm_start() will be called: let's regain 1762 * control on images. 1763 */ 1764 if (s->state == MIGRATION_STATUS_ACTIVE) { 1765 Error *local_err = NULL; 1766 1767 qemu_mutex_lock_iothread(); 1768 bdrv_invalidate_cache_all(&local_err); 1769 if (local_err) { 1770 error_report_err(local_err); 1771 } else { 1772 s->block_inactive = false; 1773 } 1774 qemu_mutex_unlock_iothread(); 1775 } 1776 1777 fail: 1778 migrate_set_state(&s->state, current_active_state, 1779 MIGRATION_STATUS_FAILED); 1780 } 1781 1782 bool migrate_colo_enabled(void) 1783 { 1784 MigrationState *s = migrate_get_current(); 1785 return s->enabled_capabilities[MIGRATION_CAPABILITY_X_COLO]; 1786 } 1787 1788 /* 1789 * Master migration thread on the source VM. 1790 * It drives the migration and pumps the data down the outgoing channel. 1791 */ 1792 static void *migration_thread(void *opaque) 1793 { 1794 MigrationState *s = opaque; 1795 /* Used by the bandwidth calcs, updated later */ 1796 int64_t initial_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); 1797 int64_t setup_start = qemu_clock_get_ms(QEMU_CLOCK_HOST); 1798 int64_t initial_bytes = 0; 1799 /* 1800 * The final stage happens when the remaining data is smaller than 1801 * this threshold; it's calculated from the requested downtime and 1802 * measured bandwidth 1803 */ 1804 int64_t threshold_size = 0; 1805 int64_t start_time = initial_time; 1806 int64_t end_time; 1807 bool old_vm_running = false; 1808 bool entered_postcopy = false; 1809 /* The active state we expect to be in; ACTIVE or POSTCOPY_ACTIVE */ 1810 enum MigrationStatus current_active_state = MIGRATION_STATUS_ACTIVE; 1811 bool enable_colo = migrate_colo_enabled(); 1812 1813 rcu_register_thread(); 1814 1815 qemu_savevm_state_header(s->to_dst_file); 1816 1817 if (s->to_dst_file) { 1818 /* Now tell the dest that it should open its end so it can reply */ 1819 qemu_savevm_send_open_return_path(s->to_dst_file); 1820 1821 /* And do a ping that will make stuff easier to debug */ 1822 qemu_savevm_send_ping(s->to_dst_file, 1); 1823 } 1824 1825 if (migrate_postcopy_ram()) { 1826 /* 1827 * Tell the destination that we *might* want to do postcopy later; 1828 * if the other end can't do postcopy it should fail now, nice and 1829 * early. 1830 */ 1831 qemu_savevm_send_postcopy_advise(s->to_dst_file); 1832 } 1833 1834 qemu_savevm_state_begin(s->to_dst_file); 1835 1836 s->setup_time = qemu_clock_get_ms(QEMU_CLOCK_HOST) - setup_start; 1837 migrate_set_state(&s->state, MIGRATION_STATUS_SETUP, 1838 MIGRATION_STATUS_ACTIVE); 1839 1840 trace_migration_thread_setup_complete(); 1841 1842 while (s->state == MIGRATION_STATUS_ACTIVE || 1843 s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE) { 1844 int64_t current_time; 1845 uint64_t pending_size; 1846 1847 if (!qemu_file_rate_limit(s->to_dst_file)) { 1848 uint64_t pend_post, pend_nonpost; 1849 1850 qemu_savevm_state_pending(s->to_dst_file, threshold_size, 1851 &pend_nonpost, &pend_post); 1852 pending_size = pend_nonpost + pend_post; 1853 trace_migrate_pending(pending_size, threshold_size, 1854 pend_post, pend_nonpost); 1855 if (pending_size && pending_size >= threshold_size) { 1856 /* Still a significant amount to transfer */ 1857 1858 if (migrate_postcopy_ram() && 1859 s->state != MIGRATION_STATUS_POSTCOPY_ACTIVE && 1860 pend_nonpost <= threshold_size && 1861 atomic_read(&s->start_postcopy)) { 1862 1863 if (!postcopy_start(s, &old_vm_running)) { 1864 current_active_state = MIGRATION_STATUS_POSTCOPY_ACTIVE; 1865 entered_postcopy = true; 1866 } 1867 1868 continue; 1869 } 1870 /* Just another iteration step */ 1871 qemu_savevm_state_iterate(s->to_dst_file, entered_postcopy); 1872 } else { 1873 trace_migration_thread_low_pending(pending_size); 1874 migration_completion(s, current_active_state, 1875 &old_vm_running, &start_time); 1876 break; 1877 } 1878 } 1879 1880 if (qemu_file_get_error(s->to_dst_file)) { 1881 migrate_set_state(&s->state, current_active_state, 1882 MIGRATION_STATUS_FAILED); 1883 trace_migration_thread_file_err(); 1884 break; 1885 } 1886 current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); 1887 if (current_time >= initial_time + BUFFER_DELAY) { 1888 uint64_t transferred_bytes = qemu_ftell(s->to_dst_file) - 1889 initial_bytes; 1890 uint64_t time_spent = current_time - initial_time; 1891 double bandwidth = (double)transferred_bytes / time_spent; 1892 threshold_size = bandwidth * s->parameters.downtime_limit; 1893 1894 s->mbps = (((double) transferred_bytes * 8.0) / 1895 ((double) time_spent / 1000.0)) / 1000.0 / 1000.0; 1896 1897 trace_migrate_transferred(transferred_bytes, time_spent, 1898 bandwidth, threshold_size); 1899 /* if we haven't sent anything, we don't want to recalculate 1900 10000 is a small enough number for our purposes */ 1901 if (ram_counters.dirty_pages_rate && transferred_bytes > 10000) { 1902 s->expected_downtime = ram_counters.dirty_pages_rate * 1903 qemu_target_page_size() / bandwidth; 1904 } 1905 1906 qemu_file_reset_rate_limit(s->to_dst_file); 1907 initial_time = current_time; 1908 initial_bytes = qemu_ftell(s->to_dst_file); 1909 } 1910 if (qemu_file_rate_limit(s->to_dst_file)) { 1911 /* usleep expects microseconds */ 1912 g_usleep((initial_time + BUFFER_DELAY - current_time)*1000); 1913 } 1914 } 1915 1916 trace_migration_thread_after_loop(); 1917 /* If we enabled cpu throttling for auto-converge, turn it off. */ 1918 cpu_throttle_stop(); 1919 end_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); 1920 1921 qemu_mutex_lock_iothread(); 1922 /* 1923 * The resource has been allocated by migration will be reused in COLO 1924 * process, so don't release them. 1925 */ 1926 if (!enable_colo) { 1927 qemu_savevm_state_cleanup(); 1928 } 1929 if (s->state == MIGRATION_STATUS_COMPLETED) { 1930 uint64_t transferred_bytes = qemu_ftell(s->to_dst_file); 1931 s->total_time = end_time - s->total_time; 1932 if (!entered_postcopy) { 1933 s->downtime = end_time - start_time; 1934 } 1935 if (s->total_time) { 1936 s->mbps = (((double) transferred_bytes * 8.0) / 1937 ((double) s->total_time)) / 1000; 1938 } 1939 runstate_set(RUN_STATE_POSTMIGRATE); 1940 } else { 1941 if (s->state == MIGRATION_STATUS_ACTIVE && enable_colo) { 1942 migrate_start_colo_process(s); 1943 qemu_savevm_state_cleanup(); 1944 /* 1945 * Fixme: we will run VM in COLO no matter its old running state. 1946 * After exited COLO, we will keep running. 1947 */ 1948 old_vm_running = true; 1949 } 1950 if (old_vm_running && !entered_postcopy) { 1951 vm_start(); 1952 } else { 1953 if (runstate_check(RUN_STATE_FINISH_MIGRATE)) { 1954 runstate_set(RUN_STATE_POSTMIGRATE); 1955 } 1956 } 1957 } 1958 qemu_bh_schedule(s->cleanup_bh); 1959 qemu_mutex_unlock_iothread(); 1960 1961 rcu_unregister_thread(); 1962 return NULL; 1963 } 1964 1965 void migrate_fd_connect(MigrationState *s) 1966 { 1967 s->expected_downtime = s->parameters.downtime_limit; 1968 s->cleanup_bh = qemu_bh_new(migrate_fd_cleanup, s); 1969 1970 qemu_file_set_blocking(s->to_dst_file, true); 1971 qemu_file_set_rate_limit(s->to_dst_file, 1972 s->parameters.max_bandwidth / XFER_LIMIT_RATIO); 1973 1974 /* Notify before starting migration thread */ 1975 notifier_list_notify(&migration_state_notifiers, s); 1976 1977 /* 1978 * Open the return path; currently for postcopy but other things might 1979 * also want it. 1980 */ 1981 if (migrate_postcopy_ram()) { 1982 if (open_return_path_on_source(s)) { 1983 error_report("Unable to open return-path for postcopy"); 1984 migrate_set_state(&s->state, MIGRATION_STATUS_SETUP, 1985 MIGRATION_STATUS_FAILED); 1986 migrate_fd_cleanup(s); 1987 return; 1988 } 1989 } 1990 1991 migrate_compress_threads_create(); 1992 qemu_thread_create(&s->thread, "live_migration", migration_thread, s, 1993 QEMU_THREAD_JOINABLE); 1994 s->migration_thread_running = true; 1995 } 1996 1997