1 /* 2 * Block dirty bitmap postcopy migration 3 * 4 * Copyright IBM, Corp. 2009 5 * Copyright (c) 2016-2017 Virtuozzo International GmbH. All rights reserved. 6 * 7 * Authors: 8 * Liran Schour <lirans@il.ibm.com> 9 * Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> 10 * 11 * This work is licensed under the terms of the GNU GPL, version 2. See 12 * the COPYING file in the top-level directory. 13 * This file is derived from migration/block.c, so it's author and IBM copyright 14 * are here, although content is quite different. 15 * 16 * Contributions after 2012-01-13 are licensed under the terms of the 17 * GNU GPL, version 2 or (at your option) any later version. 18 * 19 * *** 20 * 21 * Here postcopy migration of dirty bitmaps is realized. Only QMP-addressable 22 * bitmaps are migrated. 23 * 24 * Bitmap migration implies creating bitmap with the same name and granularity 25 * in destination QEMU. If the bitmap with the same name (for the same node) 26 * already exists on destination an error will be generated. 27 * 28 * format of migration: 29 * 30 * # Header (shared for different chunk types) 31 * 1, 2 or 4 bytes: flags (see qemu_{put,put}_flags) 32 * [ 1 byte: node alias size ] \ flags & DEVICE_NAME 33 * [ n bytes: node alias ] / 34 * [ 1 byte: bitmap alias size ] \ flags & BITMAP_NAME 35 * [ n bytes: bitmap alias ] / 36 * 37 * # Start of bitmap migration (flags & START) 38 * header 39 * be64: granularity 40 * 1 byte: bitmap flags (corresponds to BdrvDirtyBitmap) 41 * bit 0 - bitmap is enabled 42 * bit 1 - bitmap is persistent 43 * bit 2 - bitmap is autoloading 44 * bits 3-7 - reserved, must be zero 45 * 46 * # Complete of bitmap migration (flags & COMPLETE) 47 * header 48 * 49 * # Data chunk of bitmap migration 50 * header 51 * be64: start sector 52 * be32: number of sectors 53 * [ be64: buffer size ] \ ! (flags & ZEROES) 54 * [ n bytes: buffer ] / 55 * 56 * The last chunk in stream should contain flags & EOS. The chunk may skip 57 * device and/or bitmap names, assuming them to be the same with the previous 58 * chunk. 59 */ 60 61 #include "qemu/osdep.h" 62 #include "block/block.h" 63 #include "block/block_int.h" 64 #include "sysemu/block-backend.h" 65 #include "sysemu/runstate.h" 66 #include "qemu/main-loop.h" 67 #include "qemu/error-report.h" 68 #include "migration/misc.h" 69 #include "migration/migration.h" 70 #include "qemu-file.h" 71 #include "migration/vmstate.h" 72 #include "migration/register.h" 73 #include "qemu/hbitmap.h" 74 #include "qemu/cutils.h" 75 #include "qemu/id.h" 76 #include "qapi/error.h" 77 #include "qapi/qapi-commands-migration.h" 78 #include "qapi/qapi-visit-migration.h" 79 #include "qapi/clone-visitor.h" 80 #include "trace.h" 81 82 #define CHUNK_SIZE (1 << 10) 83 84 /* Flags occupy one, two or four bytes (Big Endian). The size is determined as 85 * follows: 86 * in first (most significant) byte bit 8 is clear --> one byte 87 * in first byte bit 8 is set --> two or four bytes, depending on second 88 * byte: 89 * | in second byte bit 8 is clear --> two bytes 90 * | in second byte bit 8 is set --> four bytes 91 */ 92 #define DIRTY_BITMAP_MIG_FLAG_EOS 0x01 93 #define DIRTY_BITMAP_MIG_FLAG_ZEROES 0x02 94 #define DIRTY_BITMAP_MIG_FLAG_BITMAP_NAME 0x04 95 #define DIRTY_BITMAP_MIG_FLAG_DEVICE_NAME 0x08 96 #define DIRTY_BITMAP_MIG_FLAG_START 0x10 97 #define DIRTY_BITMAP_MIG_FLAG_COMPLETE 0x20 98 #define DIRTY_BITMAP_MIG_FLAG_BITS 0x40 99 100 #define DIRTY_BITMAP_MIG_EXTRA_FLAGS 0x80 101 102 #define DIRTY_BITMAP_MIG_START_FLAG_ENABLED 0x01 103 #define DIRTY_BITMAP_MIG_START_FLAG_PERSISTENT 0x02 104 /* 0x04 was "AUTOLOAD" flags on older versions, now it is ignored */ 105 #define DIRTY_BITMAP_MIG_START_FLAG_RESERVED_MASK 0xf8 106 107 /* State of one bitmap during save process */ 108 typedef struct SaveBitmapState { 109 /* Written during setup phase. */ 110 BlockDriverState *bs; 111 char *node_alias; 112 char *bitmap_alias; 113 BdrvDirtyBitmap *bitmap; 114 uint64_t total_sectors; 115 uint64_t sectors_per_chunk; 116 QSIMPLEQ_ENTRY(SaveBitmapState) entry; 117 uint8_t flags; 118 119 /* For bulk phase. */ 120 bool bulk_completed; 121 uint64_t cur_sector; 122 } SaveBitmapState; 123 124 /* State of the dirty bitmap migration (DBM) during save process */ 125 typedef struct DBMSaveState { 126 QSIMPLEQ_HEAD(, SaveBitmapState) dbms_list; 127 128 bool bulk_completed; 129 bool no_bitmaps; 130 131 /* for send_bitmap_bits() */ 132 BlockDriverState *prev_bs; 133 BdrvDirtyBitmap *prev_bitmap; 134 } DBMSaveState; 135 136 typedef struct LoadBitmapState { 137 BlockDriverState *bs; 138 BdrvDirtyBitmap *bitmap; 139 bool migrated; 140 bool enabled; 141 } LoadBitmapState; 142 143 /* State of the dirty bitmap migration (DBM) during load process */ 144 typedef struct DBMLoadState { 145 uint32_t flags; 146 char node_alias[256]; 147 char bitmap_alias[256]; 148 char bitmap_name[BDRV_BITMAP_MAX_NAME_SIZE + 1]; 149 BlockDriverState *bs; 150 BdrvDirtyBitmap *bitmap; 151 152 bool before_vm_start_handled; /* set in dirty_bitmap_mig_before_vm_start */ 153 BitmapMigrationBitmapAlias *bmap_inner; 154 155 /* 156 * cancelled 157 * Incoming migration is cancelled for some reason. That means that we 158 * still should read our chunks from migration stream, to not affect other 159 * migration objects (like RAM), but just ignore them and do not touch any 160 * bitmaps or nodes. 161 */ 162 bool cancelled; 163 164 GSList *bitmaps; 165 QemuMutex lock; /* protect bitmaps */ 166 } DBMLoadState; 167 168 typedef struct DBMState { 169 DBMSaveState save; 170 DBMLoadState load; 171 } DBMState; 172 173 static DBMState dbm_state; 174 175 /* For hash tables that map node/bitmap names to aliases */ 176 typedef struct AliasMapInnerNode { 177 char *string; 178 GHashTable *subtree; 179 } AliasMapInnerNode; 180 181 static void free_alias_map_inner_node(void *amin_ptr) 182 { 183 AliasMapInnerNode *amin = amin_ptr; 184 185 g_free(amin->string); 186 g_hash_table_unref(amin->subtree); 187 g_free(amin); 188 } 189 190 /** 191 * Construct an alias map based on the given QMP structure. 192 * 193 * (Note that we cannot store such maps in the MigrationParameters 194 * object, because that struct is defined by the QAPI schema, which 195 * makes it basically impossible to have dicts with arbitrary keys. 196 * Therefore, we instead have to construct these maps when migration 197 * starts.) 198 * 199 * @bbm is the block_bitmap_mapping from the migration parameters. 200 * 201 * If @name_to_alias is true, the returned hash table will map node 202 * and bitmap names to their respective aliases (for outgoing 203 * migration). 204 * 205 * If @name_to_alias is false, the returned hash table will map node 206 * and bitmap aliases to their respective names (for incoming 207 * migration). 208 * 209 * The hash table maps node names/aliases to AliasMapInnerNode 210 * objects, whose .string is the respective node alias/name, and whose 211 * .subtree table maps bitmap names/aliases to the respective bitmap 212 * alias/name. 213 */ 214 static GHashTable *construct_alias_map(const BitmapMigrationNodeAliasList *bbm, 215 bool name_to_alias, 216 Error **errp) 217 { 218 GHashTable *alias_map; 219 size_t max_node_name_len = sizeof_field(BlockDriverState, node_name) - 1; 220 221 alias_map = g_hash_table_new_full(g_str_hash, g_str_equal, 222 g_free, free_alias_map_inner_node); 223 224 for (; bbm; bbm = bbm->next) { 225 const BitmapMigrationNodeAlias *bmna = bbm->value; 226 const BitmapMigrationBitmapAliasList *bmbal; 227 AliasMapInnerNode *amin; 228 GHashTable *bitmaps_map; 229 const char *node_map_from, *node_map_to; 230 GDestroyNotify gdn; 231 232 if (!id_wellformed(bmna->alias)) { 233 error_setg(errp, "The node alias '%s' is not well-formed", 234 bmna->alias); 235 goto fail; 236 } 237 238 if (strlen(bmna->alias) > UINT8_MAX) { 239 error_setg(errp, "The node alias '%s' is longer than %u bytes", 240 bmna->alias, UINT8_MAX); 241 goto fail; 242 } 243 244 if (strlen(bmna->node_name) > max_node_name_len) { 245 error_setg(errp, "The node name '%s' is longer than %zu bytes", 246 bmna->node_name, max_node_name_len); 247 goto fail; 248 } 249 250 if (name_to_alias) { 251 if (g_hash_table_contains(alias_map, bmna->node_name)) { 252 error_setg(errp, "The node name '%s' is mapped twice", 253 bmna->node_name); 254 goto fail; 255 } 256 257 node_map_from = bmna->node_name; 258 node_map_to = bmna->alias; 259 } else { 260 if (g_hash_table_contains(alias_map, bmna->alias)) { 261 error_setg(errp, "The node alias '%s' is used twice", 262 bmna->alias); 263 goto fail; 264 } 265 266 node_map_from = bmna->alias; 267 node_map_to = bmna->node_name; 268 } 269 270 gdn = (GDestroyNotify) qapi_free_BitmapMigrationBitmapAlias; 271 bitmaps_map = g_hash_table_new_full(g_str_hash, g_str_equal, g_free, 272 gdn); 273 274 amin = g_new(AliasMapInnerNode, 1); 275 *amin = (AliasMapInnerNode){ 276 .string = g_strdup(node_map_to), 277 .subtree = bitmaps_map, 278 }; 279 280 g_hash_table_insert(alias_map, g_strdup(node_map_from), amin); 281 282 for (bmbal = bmna->bitmaps; bmbal; bmbal = bmbal->next) { 283 const BitmapMigrationBitmapAlias *bmba = bmbal->value; 284 const char *bmap_map_from; 285 286 if (strlen(bmba->alias) > UINT8_MAX) { 287 error_setg(errp, 288 "The bitmap alias '%s' is longer than %u bytes", 289 bmba->alias, UINT8_MAX); 290 goto fail; 291 } 292 293 if (strlen(bmba->name) > BDRV_BITMAP_MAX_NAME_SIZE) { 294 error_setg(errp, "The bitmap name '%s' is longer than %d bytes", 295 bmba->name, BDRV_BITMAP_MAX_NAME_SIZE); 296 goto fail; 297 } 298 299 if (name_to_alias) { 300 bmap_map_from = bmba->name; 301 302 if (g_hash_table_contains(bitmaps_map, bmba->name)) { 303 error_setg(errp, "The bitmap '%s'/'%s' is mapped twice", 304 bmna->node_name, bmba->name); 305 goto fail; 306 } 307 } else { 308 bmap_map_from = bmba->alias; 309 310 if (g_hash_table_contains(bitmaps_map, bmba->alias)) { 311 error_setg(errp, "The bitmap alias '%s'/'%s' is used twice", 312 bmna->alias, bmba->alias); 313 goto fail; 314 } 315 } 316 317 g_hash_table_insert(bitmaps_map, g_strdup(bmap_map_from), 318 QAPI_CLONE(BitmapMigrationBitmapAlias, bmba)); 319 } 320 } 321 322 return alias_map; 323 324 fail: 325 g_hash_table_destroy(alias_map); 326 return NULL; 327 } 328 329 /** 330 * Run construct_alias_map() in both directions to check whether @bbm 331 * is valid. 332 * (This function is to be used by migration/migration.c to validate 333 * the user-specified block-bitmap-mapping migration parameter.) 334 * 335 * Returns true if and only if the mapping is valid. 336 */ 337 bool check_dirty_bitmap_mig_alias_map(const BitmapMigrationNodeAliasList *bbm, 338 Error **errp) 339 { 340 GHashTable *alias_map; 341 342 alias_map = construct_alias_map(bbm, true, errp); 343 if (!alias_map) { 344 return false; 345 } 346 g_hash_table_destroy(alias_map); 347 348 alias_map = construct_alias_map(bbm, false, errp); 349 if (!alias_map) { 350 return false; 351 } 352 g_hash_table_destroy(alias_map); 353 354 return true; 355 } 356 357 static uint32_t qemu_get_bitmap_flags(QEMUFile *f) 358 { 359 uint8_t flags = qemu_get_byte(f); 360 if (flags & DIRTY_BITMAP_MIG_EXTRA_FLAGS) { 361 flags = flags << 8 | qemu_get_byte(f); 362 if (flags & DIRTY_BITMAP_MIG_EXTRA_FLAGS) { 363 flags = flags << 16 | qemu_get_be16(f); 364 } 365 } 366 367 return flags; 368 } 369 370 static void qemu_put_bitmap_flags(QEMUFile *f, uint32_t flags) 371 { 372 /* The code currently does not send flags as more than one byte */ 373 assert(!(flags & (0xffffff00 | DIRTY_BITMAP_MIG_EXTRA_FLAGS))); 374 375 qemu_put_byte(f, flags); 376 } 377 378 static void send_bitmap_header(QEMUFile *f, DBMSaveState *s, 379 SaveBitmapState *dbms, uint32_t additional_flags) 380 { 381 BlockDriverState *bs = dbms->bs; 382 BdrvDirtyBitmap *bitmap = dbms->bitmap; 383 uint32_t flags = additional_flags; 384 trace_send_bitmap_header_enter(); 385 386 if (bs != s->prev_bs) { 387 s->prev_bs = bs; 388 flags |= DIRTY_BITMAP_MIG_FLAG_DEVICE_NAME; 389 } 390 391 if (bitmap != s->prev_bitmap) { 392 s->prev_bitmap = bitmap; 393 flags |= DIRTY_BITMAP_MIG_FLAG_BITMAP_NAME; 394 } 395 396 qemu_put_bitmap_flags(f, flags); 397 398 if (flags & DIRTY_BITMAP_MIG_FLAG_DEVICE_NAME) { 399 qemu_put_counted_string(f, dbms->node_alias); 400 } 401 402 if (flags & DIRTY_BITMAP_MIG_FLAG_BITMAP_NAME) { 403 qemu_put_counted_string(f, dbms->bitmap_alias); 404 } 405 } 406 407 static void send_bitmap_start(QEMUFile *f, DBMSaveState *s, 408 SaveBitmapState *dbms) 409 { 410 send_bitmap_header(f, s, dbms, DIRTY_BITMAP_MIG_FLAG_START); 411 qemu_put_be32(f, bdrv_dirty_bitmap_granularity(dbms->bitmap)); 412 qemu_put_byte(f, dbms->flags); 413 } 414 415 static void send_bitmap_complete(QEMUFile *f, DBMSaveState *s, 416 SaveBitmapState *dbms) 417 { 418 send_bitmap_header(f, s, dbms, DIRTY_BITMAP_MIG_FLAG_COMPLETE); 419 } 420 421 static void send_bitmap_bits(QEMUFile *f, DBMSaveState *s, 422 SaveBitmapState *dbms, 423 uint64_t start_sector, uint32_t nr_sectors) 424 { 425 /* align for buffer_is_zero() */ 426 uint64_t align = 4 * sizeof(long); 427 uint64_t unaligned_size = 428 bdrv_dirty_bitmap_serialization_size( 429 dbms->bitmap, start_sector << BDRV_SECTOR_BITS, 430 (uint64_t)nr_sectors << BDRV_SECTOR_BITS); 431 uint64_t buf_size = QEMU_ALIGN_UP(unaligned_size, align); 432 uint8_t *buf = g_malloc0(buf_size); 433 uint32_t flags = DIRTY_BITMAP_MIG_FLAG_BITS; 434 435 bdrv_dirty_bitmap_serialize_part( 436 dbms->bitmap, buf, start_sector << BDRV_SECTOR_BITS, 437 (uint64_t)nr_sectors << BDRV_SECTOR_BITS); 438 439 if (buffer_is_zero(buf, buf_size)) { 440 g_free(buf); 441 buf = NULL; 442 flags |= DIRTY_BITMAP_MIG_FLAG_ZEROES; 443 } 444 445 trace_send_bitmap_bits(flags, start_sector, nr_sectors, buf_size); 446 447 send_bitmap_header(f, s, dbms, flags); 448 449 qemu_put_be64(f, start_sector); 450 qemu_put_be32(f, nr_sectors); 451 452 /* if a block is zero we need to flush here since the network 453 * bandwidth is now a lot higher than the storage device bandwidth. 454 * thus if we queue zero blocks we slow down the migration. */ 455 if (flags & DIRTY_BITMAP_MIG_FLAG_ZEROES) { 456 qemu_fflush(f); 457 } else { 458 qemu_put_be64(f, buf_size); 459 qemu_put_buffer(f, buf, buf_size); 460 } 461 462 g_free(buf); 463 } 464 465 /* Called with iothread lock taken. */ 466 static void dirty_bitmap_do_save_cleanup(DBMSaveState *s) 467 { 468 SaveBitmapState *dbms; 469 470 while ((dbms = QSIMPLEQ_FIRST(&s->dbms_list)) != NULL) { 471 QSIMPLEQ_REMOVE_HEAD(&s->dbms_list, entry); 472 bdrv_dirty_bitmap_set_busy(dbms->bitmap, false); 473 bdrv_unref(dbms->bs); 474 g_free(dbms->node_alias); 475 g_free(dbms->bitmap_alias); 476 g_free(dbms); 477 } 478 } 479 480 /* Called with iothread lock taken. */ 481 static int add_bitmaps_to_list(DBMSaveState *s, BlockDriverState *bs, 482 const char *bs_name, GHashTable *alias_map) 483 { 484 BdrvDirtyBitmap *bitmap; 485 SaveBitmapState *dbms; 486 GHashTable *bitmap_aliases; 487 const char *node_alias, *bitmap_name, *bitmap_alias; 488 Error *local_err = NULL; 489 490 /* When an alias map is given, @bs_name must be @bs's node name */ 491 assert(!alias_map || !strcmp(bs_name, bdrv_get_node_name(bs))); 492 493 FOR_EACH_DIRTY_BITMAP(bs, bitmap) { 494 if (bdrv_dirty_bitmap_name(bitmap)) { 495 break; 496 } 497 } 498 if (!bitmap) { 499 return 0; 500 } 501 502 bitmap_name = bdrv_dirty_bitmap_name(bitmap); 503 504 if (!bs_name || strcmp(bs_name, "") == 0) { 505 error_report("Bitmap '%s' in unnamed node can't be migrated", 506 bitmap_name); 507 return -1; 508 } 509 510 if (alias_map) { 511 const AliasMapInnerNode *amin = g_hash_table_lookup(alias_map, bs_name); 512 513 if (!amin) { 514 /* Skip bitmaps on nodes with no alias */ 515 return 0; 516 } 517 518 node_alias = amin->string; 519 bitmap_aliases = amin->subtree; 520 } else { 521 node_alias = bs_name; 522 bitmap_aliases = NULL; 523 } 524 525 if (node_alias[0] == '#') { 526 error_report("Bitmap '%s' in a node with auto-generated " 527 "name '%s' can't be migrated", 528 bitmap_name, node_alias); 529 return -1; 530 } 531 532 FOR_EACH_DIRTY_BITMAP(bs, bitmap) { 533 BitmapMigrationBitmapAliasTransform *bitmap_transform = NULL; 534 bitmap_name = bdrv_dirty_bitmap_name(bitmap); 535 if (!bitmap_name) { 536 continue; 537 } 538 539 if (bdrv_dirty_bitmap_check(bitmap, BDRV_BITMAP_DEFAULT, &local_err)) { 540 error_report_err(local_err); 541 return -1; 542 } 543 544 if (bitmap_aliases) { 545 BitmapMigrationBitmapAlias *bmap_inner; 546 547 bmap_inner = g_hash_table_lookup(bitmap_aliases, bitmap_name); 548 if (!bmap_inner) { 549 /* Skip bitmaps with no alias */ 550 continue; 551 } 552 553 bitmap_alias = bmap_inner->alias; 554 if (bmap_inner->has_transform) { 555 bitmap_transform = bmap_inner->transform; 556 } 557 } else { 558 if (strlen(bitmap_name) > UINT8_MAX) { 559 error_report("Cannot migrate bitmap '%s' on node '%s': " 560 "Name is longer than %u bytes", 561 bitmap_name, bs_name, UINT8_MAX); 562 return -1; 563 } 564 bitmap_alias = bitmap_name; 565 } 566 567 bdrv_ref(bs); 568 bdrv_dirty_bitmap_set_busy(bitmap, true); 569 570 dbms = g_new0(SaveBitmapState, 1); 571 dbms->bs = bs; 572 dbms->node_alias = g_strdup(node_alias); 573 dbms->bitmap_alias = g_strdup(bitmap_alias); 574 dbms->bitmap = bitmap; 575 dbms->total_sectors = bdrv_nb_sectors(bs); 576 dbms->sectors_per_chunk = CHUNK_SIZE * 8LLU * 577 (bdrv_dirty_bitmap_granularity(bitmap) >> BDRV_SECTOR_BITS); 578 assert(dbms->sectors_per_chunk != 0); 579 if (bdrv_dirty_bitmap_enabled(bitmap)) { 580 dbms->flags |= DIRTY_BITMAP_MIG_START_FLAG_ENABLED; 581 } 582 if (bitmap_transform && 583 bitmap_transform->has_persistent) { 584 if (bitmap_transform->persistent) { 585 dbms->flags |= DIRTY_BITMAP_MIG_START_FLAG_PERSISTENT; 586 } 587 } else { 588 if (bdrv_dirty_bitmap_get_persistence(bitmap)) { 589 dbms->flags |= DIRTY_BITMAP_MIG_START_FLAG_PERSISTENT; 590 } 591 } 592 593 QSIMPLEQ_INSERT_TAIL(&s->dbms_list, dbms, entry); 594 } 595 596 return 0; 597 } 598 599 /* Called with iothread lock taken. */ 600 static int init_dirty_bitmap_migration(DBMSaveState *s) 601 { 602 BlockDriverState *bs; 603 SaveBitmapState *dbms; 604 GHashTable *handled_by_blk = g_hash_table_new(NULL, NULL); 605 BlockBackend *blk; 606 const MigrationParameters *mig_params = &migrate_get_current()->parameters; 607 GHashTable *alias_map = NULL; 608 609 if (mig_params->has_block_bitmap_mapping) { 610 alias_map = construct_alias_map(mig_params->block_bitmap_mapping, true, 611 &error_abort); 612 } 613 614 s->bulk_completed = false; 615 s->prev_bs = NULL; 616 s->prev_bitmap = NULL; 617 s->no_bitmaps = false; 618 619 if (!alias_map) { 620 /* 621 * Use blockdevice name for direct (or filtered) children of named block 622 * backends. 623 */ 624 for (blk = blk_next(NULL); blk; blk = blk_next(blk)) { 625 const char *name = blk_name(blk); 626 627 if (!name || strcmp(name, "") == 0) { 628 continue; 629 } 630 631 bs = blk_bs(blk); 632 633 /* Skip filters without bitmaps */ 634 while (bs && bs->drv && bs->drv->is_filter && 635 !bdrv_has_named_bitmaps(bs)) 636 { 637 bs = bdrv_filter_bs(bs); 638 } 639 640 if (bs && bs->drv && !bs->drv->is_filter) { 641 if (add_bitmaps_to_list(s, bs, name, NULL)) { 642 goto fail; 643 } 644 g_hash_table_add(handled_by_blk, bs); 645 } 646 } 647 } 648 649 for (bs = bdrv_next_all_states(NULL); bs; bs = bdrv_next_all_states(bs)) { 650 if (g_hash_table_contains(handled_by_blk, bs)) { 651 continue; 652 } 653 654 if (add_bitmaps_to_list(s, bs, bdrv_get_node_name(bs), alias_map)) { 655 goto fail; 656 } 657 } 658 659 /* unset migration flags here, to not roll back it */ 660 QSIMPLEQ_FOREACH(dbms, &s->dbms_list, entry) { 661 bdrv_dirty_bitmap_skip_store(dbms->bitmap, true); 662 } 663 664 if (QSIMPLEQ_EMPTY(&s->dbms_list)) { 665 s->no_bitmaps = true; 666 } 667 668 g_hash_table_destroy(handled_by_blk); 669 if (alias_map) { 670 g_hash_table_destroy(alias_map); 671 } 672 673 return 0; 674 675 fail: 676 g_hash_table_destroy(handled_by_blk); 677 if (alias_map) { 678 g_hash_table_destroy(alias_map); 679 } 680 dirty_bitmap_do_save_cleanup(s); 681 682 return -1; 683 } 684 685 /* Called with no lock taken. */ 686 static void bulk_phase_send_chunk(QEMUFile *f, DBMSaveState *s, 687 SaveBitmapState *dbms) 688 { 689 uint32_t nr_sectors = MIN(dbms->total_sectors - dbms->cur_sector, 690 dbms->sectors_per_chunk); 691 692 send_bitmap_bits(f, s, dbms, dbms->cur_sector, nr_sectors); 693 694 dbms->cur_sector += nr_sectors; 695 if (dbms->cur_sector >= dbms->total_sectors) { 696 dbms->bulk_completed = true; 697 } 698 } 699 700 /* Called with no lock taken. */ 701 static void bulk_phase(QEMUFile *f, DBMSaveState *s, bool limit) 702 { 703 SaveBitmapState *dbms; 704 705 QSIMPLEQ_FOREACH(dbms, &s->dbms_list, entry) { 706 while (!dbms->bulk_completed) { 707 bulk_phase_send_chunk(f, s, dbms); 708 if (limit && qemu_file_rate_limit(f)) { 709 return; 710 } 711 } 712 } 713 714 s->bulk_completed = true; 715 } 716 717 /* for SaveVMHandlers */ 718 static void dirty_bitmap_save_cleanup(void *opaque) 719 { 720 DBMSaveState *s = &((DBMState *)opaque)->save; 721 722 dirty_bitmap_do_save_cleanup(s); 723 } 724 725 static int dirty_bitmap_save_iterate(QEMUFile *f, void *opaque) 726 { 727 DBMSaveState *s = &((DBMState *)opaque)->save; 728 729 trace_dirty_bitmap_save_iterate(migration_in_postcopy()); 730 731 if (migration_in_postcopy() && !s->bulk_completed) { 732 bulk_phase(f, s, true); 733 } 734 735 qemu_put_bitmap_flags(f, DIRTY_BITMAP_MIG_FLAG_EOS); 736 737 return s->bulk_completed; 738 } 739 740 /* Called with iothread lock taken. */ 741 742 static int dirty_bitmap_save_complete(QEMUFile *f, void *opaque) 743 { 744 DBMSaveState *s = &((DBMState *)opaque)->save; 745 SaveBitmapState *dbms; 746 trace_dirty_bitmap_save_complete_enter(); 747 748 if (!s->bulk_completed) { 749 bulk_phase(f, s, false); 750 } 751 752 QSIMPLEQ_FOREACH(dbms, &s->dbms_list, entry) { 753 send_bitmap_complete(f, s, dbms); 754 } 755 756 qemu_put_bitmap_flags(f, DIRTY_BITMAP_MIG_FLAG_EOS); 757 758 trace_dirty_bitmap_save_complete_finish(); 759 760 dirty_bitmap_save_cleanup(opaque); 761 return 0; 762 } 763 764 static void dirty_bitmap_save_pending(QEMUFile *f, void *opaque, 765 uint64_t max_size, 766 uint64_t *res_precopy_only, 767 uint64_t *res_compatible, 768 uint64_t *res_postcopy_only) 769 { 770 DBMSaveState *s = &((DBMState *)opaque)->save; 771 SaveBitmapState *dbms; 772 uint64_t pending = 0; 773 774 qemu_mutex_lock_iothread(); 775 776 QSIMPLEQ_FOREACH(dbms, &s->dbms_list, entry) { 777 uint64_t gran = bdrv_dirty_bitmap_granularity(dbms->bitmap); 778 uint64_t sectors = dbms->bulk_completed ? 0 : 779 dbms->total_sectors - dbms->cur_sector; 780 781 pending += DIV_ROUND_UP(sectors * BDRV_SECTOR_SIZE, gran); 782 } 783 784 qemu_mutex_unlock_iothread(); 785 786 trace_dirty_bitmap_save_pending(pending, max_size); 787 788 *res_postcopy_only += pending; 789 } 790 791 /* First occurrence of this bitmap. It should be created if doesn't exist */ 792 static int dirty_bitmap_load_start(QEMUFile *f, DBMLoadState *s) 793 { 794 Error *local_err = NULL; 795 uint32_t granularity = qemu_get_be32(f); 796 uint8_t flags = qemu_get_byte(f); 797 LoadBitmapState *b; 798 bool persistent; 799 800 if (s->cancelled) { 801 return 0; 802 } 803 804 if (s->bitmap) { 805 error_report("Bitmap with the same name ('%s') already exists on " 806 "destination", bdrv_dirty_bitmap_name(s->bitmap)); 807 return -EINVAL; 808 } else { 809 s->bitmap = bdrv_create_dirty_bitmap(s->bs, granularity, 810 s->bitmap_name, &local_err); 811 if (!s->bitmap) { 812 error_report_err(local_err); 813 return -EINVAL; 814 } 815 } 816 817 if (flags & DIRTY_BITMAP_MIG_START_FLAG_RESERVED_MASK) { 818 error_report("Unknown flags in migrated dirty bitmap header: %x", 819 flags); 820 return -EINVAL; 821 } 822 823 if (s->bmap_inner && 824 s->bmap_inner->has_transform && 825 s->bmap_inner->transform->has_persistent) { 826 persistent = s->bmap_inner->transform->persistent; 827 } else { 828 persistent = flags & DIRTY_BITMAP_MIG_START_FLAG_PERSISTENT; 829 } 830 831 if (persistent) { 832 bdrv_dirty_bitmap_set_persistence(s->bitmap, true); 833 } 834 835 bdrv_disable_dirty_bitmap(s->bitmap); 836 if (flags & DIRTY_BITMAP_MIG_START_FLAG_ENABLED) { 837 bdrv_dirty_bitmap_create_successor(s->bitmap, &local_err); 838 if (local_err) { 839 error_report_err(local_err); 840 return -EINVAL; 841 } 842 } else { 843 bdrv_dirty_bitmap_set_busy(s->bitmap, true); 844 } 845 846 b = g_new(LoadBitmapState, 1); 847 b->bs = s->bs; 848 b->bitmap = s->bitmap; 849 b->migrated = false; 850 b->enabled = flags & DIRTY_BITMAP_MIG_START_FLAG_ENABLED; 851 852 s->bitmaps = g_slist_prepend(s->bitmaps, b); 853 854 return 0; 855 } 856 857 /* 858 * before_vm_start_handle_item 859 * 860 * g_slist_foreach helper 861 * 862 * item is LoadBitmapState* 863 * opaque is DBMLoadState* 864 */ 865 static void before_vm_start_handle_item(void *item, void *opaque) 866 { 867 DBMLoadState *s = opaque; 868 LoadBitmapState *b = item; 869 870 if (b->enabled) { 871 if (b->migrated) { 872 bdrv_enable_dirty_bitmap(b->bitmap); 873 } else { 874 bdrv_dirty_bitmap_enable_successor(b->bitmap); 875 } 876 } 877 878 if (b->migrated) { 879 s->bitmaps = g_slist_remove(s->bitmaps, b); 880 g_free(b); 881 } 882 } 883 884 void dirty_bitmap_mig_before_vm_start(void) 885 { 886 DBMLoadState *s = &dbm_state.load; 887 qemu_mutex_lock(&s->lock); 888 889 assert(!s->before_vm_start_handled); 890 g_slist_foreach(s->bitmaps, before_vm_start_handle_item, s); 891 s->before_vm_start_handled = true; 892 893 qemu_mutex_unlock(&s->lock); 894 } 895 896 static void cancel_incoming_locked(DBMLoadState *s) 897 { 898 GSList *item; 899 900 if (s->cancelled) { 901 return; 902 } 903 904 s->cancelled = true; 905 s->bs = NULL; 906 s->bitmap = NULL; 907 908 /* Drop all unfinished bitmaps */ 909 for (item = s->bitmaps; item; item = g_slist_next(item)) { 910 LoadBitmapState *b = item->data; 911 912 /* 913 * Bitmap must be unfinished, as finished bitmaps should already be 914 * removed from the list. 915 */ 916 assert(!s->before_vm_start_handled || !b->migrated); 917 if (bdrv_dirty_bitmap_has_successor(b->bitmap)) { 918 bdrv_reclaim_dirty_bitmap(b->bitmap, &error_abort); 919 } else { 920 bdrv_dirty_bitmap_set_busy(b->bitmap, false); 921 } 922 bdrv_release_dirty_bitmap(b->bitmap); 923 } 924 925 g_slist_free_full(s->bitmaps, g_free); 926 s->bitmaps = NULL; 927 } 928 929 void dirty_bitmap_mig_cancel_outgoing(void) 930 { 931 dirty_bitmap_do_save_cleanup(&dbm_state.save); 932 } 933 934 void dirty_bitmap_mig_cancel_incoming(void) 935 { 936 DBMLoadState *s = &dbm_state.load; 937 938 qemu_mutex_lock(&s->lock); 939 940 cancel_incoming_locked(s); 941 942 qemu_mutex_unlock(&s->lock); 943 } 944 945 static void dirty_bitmap_load_complete(QEMUFile *f, DBMLoadState *s) 946 { 947 GSList *item; 948 trace_dirty_bitmap_load_complete(); 949 950 if (s->cancelled) { 951 return; 952 } 953 954 bdrv_dirty_bitmap_deserialize_finish(s->bitmap); 955 956 if (bdrv_dirty_bitmap_has_successor(s->bitmap)) { 957 bdrv_reclaim_dirty_bitmap(s->bitmap, &error_abort); 958 } else { 959 bdrv_dirty_bitmap_set_busy(s->bitmap, false); 960 } 961 962 for (item = s->bitmaps; item; item = g_slist_next(item)) { 963 LoadBitmapState *b = item->data; 964 965 if (b->bitmap == s->bitmap) { 966 b->migrated = true; 967 if (s->before_vm_start_handled) { 968 s->bitmaps = g_slist_remove(s->bitmaps, b); 969 g_free(b); 970 } 971 break; 972 } 973 } 974 } 975 976 static int dirty_bitmap_load_bits(QEMUFile *f, DBMLoadState *s) 977 { 978 uint64_t first_byte = qemu_get_be64(f) << BDRV_SECTOR_BITS; 979 uint64_t nr_bytes = (uint64_t)qemu_get_be32(f) << BDRV_SECTOR_BITS; 980 trace_dirty_bitmap_load_bits_enter(first_byte >> BDRV_SECTOR_BITS, 981 nr_bytes >> BDRV_SECTOR_BITS); 982 983 if (s->flags & DIRTY_BITMAP_MIG_FLAG_ZEROES) { 984 trace_dirty_bitmap_load_bits_zeroes(); 985 if (!s->cancelled) { 986 bdrv_dirty_bitmap_deserialize_zeroes(s->bitmap, first_byte, 987 nr_bytes, false); 988 } 989 } else { 990 size_t ret; 991 g_autofree uint8_t *buf = NULL; 992 uint64_t buf_size = qemu_get_be64(f); 993 uint64_t needed_size; 994 995 /* 996 * The actual check for buf_size is done a bit later. We can't do it in 997 * cancelled mode as we don't have the bitmap to check the constraints 998 * (so, we allocate a buffer and read prior to the check). On the other 999 * hand, we shouldn't blindly g_malloc the number from the stream. 1000 * Actually one chunk should not be larger than CHUNK_SIZE. Let's allow 1001 * a bit larger (which means that bitmap migration will fail anyway and 1002 * the whole migration will most probably fail soon due to broken 1003 * stream). 1004 */ 1005 if (buf_size > 10 * CHUNK_SIZE) { 1006 error_report("Bitmap migration stream buffer allocation request " 1007 "is too large"); 1008 return -EIO; 1009 } 1010 1011 buf = g_malloc(buf_size); 1012 ret = qemu_get_buffer(f, buf, buf_size); 1013 if (ret != buf_size) { 1014 error_report("Failed to read bitmap bits"); 1015 return -EIO; 1016 } 1017 1018 if (s->cancelled) { 1019 return 0; 1020 } 1021 1022 needed_size = bdrv_dirty_bitmap_serialization_size(s->bitmap, 1023 first_byte, 1024 nr_bytes); 1025 1026 if (needed_size > buf_size || 1027 buf_size > QEMU_ALIGN_UP(needed_size, 4 * sizeof(long)) 1028 /* Here used same alignment as in send_bitmap_bits */ 1029 ) { 1030 error_report("Migrated bitmap granularity doesn't " 1031 "match the destination bitmap '%s' granularity", 1032 bdrv_dirty_bitmap_name(s->bitmap)); 1033 cancel_incoming_locked(s); 1034 return 0; 1035 } 1036 1037 bdrv_dirty_bitmap_deserialize_part(s->bitmap, buf, first_byte, nr_bytes, 1038 false); 1039 } 1040 1041 return 0; 1042 } 1043 1044 static int dirty_bitmap_load_header(QEMUFile *f, DBMLoadState *s, 1045 GHashTable *alias_map) 1046 { 1047 GHashTable *bitmap_alias_map = NULL; 1048 Error *local_err = NULL; 1049 bool nothing; 1050 s->flags = qemu_get_bitmap_flags(f); 1051 trace_dirty_bitmap_load_header(s->flags); 1052 1053 nothing = s->flags == (s->flags & DIRTY_BITMAP_MIG_FLAG_EOS); 1054 1055 if (s->flags & DIRTY_BITMAP_MIG_FLAG_DEVICE_NAME) { 1056 if (!qemu_get_counted_string(f, s->node_alias)) { 1057 error_report("Unable to read node alias string"); 1058 return -EINVAL; 1059 } 1060 1061 if (!s->cancelled) { 1062 if (alias_map) { 1063 const AliasMapInnerNode *amin; 1064 1065 amin = g_hash_table_lookup(alias_map, s->node_alias); 1066 if (!amin) { 1067 error_setg(&local_err, "Error: Unknown node alias '%s'", 1068 s->node_alias); 1069 s->bs = NULL; 1070 } else { 1071 bitmap_alias_map = amin->subtree; 1072 s->bs = bdrv_lookup_bs(NULL, amin->string, &local_err); 1073 } 1074 } else { 1075 s->bs = bdrv_lookup_bs(s->node_alias, s->node_alias, 1076 &local_err); 1077 } 1078 if (!s->bs) { 1079 error_report_err(local_err); 1080 cancel_incoming_locked(s); 1081 } 1082 } 1083 } else if (s->bs) { 1084 if (alias_map) { 1085 const AliasMapInnerNode *amin; 1086 1087 /* Must be present in the map, or s->bs would not be set */ 1088 amin = g_hash_table_lookup(alias_map, s->node_alias); 1089 assert(amin != NULL); 1090 1091 bitmap_alias_map = amin->subtree; 1092 } 1093 } else if (!nothing && !s->cancelled) { 1094 error_report("Error: block device name is not set"); 1095 cancel_incoming_locked(s); 1096 } 1097 1098 assert(nothing || s->cancelled || !!alias_map == !!bitmap_alias_map); 1099 1100 if (s->flags & DIRTY_BITMAP_MIG_FLAG_BITMAP_NAME) { 1101 const char *bitmap_name; 1102 1103 if (!qemu_get_counted_string(f, s->bitmap_alias)) { 1104 error_report("Unable to read bitmap alias string"); 1105 return -EINVAL; 1106 } 1107 1108 bitmap_name = s->bitmap_alias; 1109 if (!s->cancelled && bitmap_alias_map) { 1110 BitmapMigrationBitmapAlias *bmap_inner; 1111 1112 bmap_inner = g_hash_table_lookup(bitmap_alias_map, s->bitmap_alias); 1113 if (!bmap_inner) { 1114 error_report("Error: Unknown bitmap alias '%s' on node " 1115 "'%s' (alias '%s')", s->bitmap_alias, 1116 s->bs->node_name, s->node_alias); 1117 cancel_incoming_locked(s); 1118 } else { 1119 bitmap_name = bmap_inner->name; 1120 } 1121 1122 s->bmap_inner = bmap_inner; 1123 } 1124 1125 if (!s->cancelled) { 1126 g_strlcpy(s->bitmap_name, bitmap_name, sizeof(s->bitmap_name)); 1127 s->bitmap = bdrv_find_dirty_bitmap(s->bs, s->bitmap_name); 1128 1129 /* 1130 * bitmap may be NULL here, it wouldn't be an error if it is the 1131 * first occurrence of the bitmap 1132 */ 1133 if (!s->bitmap && !(s->flags & DIRTY_BITMAP_MIG_FLAG_START)) { 1134 error_report("Error: unknown dirty bitmap " 1135 "'%s' for block device '%s'", 1136 s->bitmap_name, s->bs->node_name); 1137 cancel_incoming_locked(s); 1138 } 1139 } 1140 } else if (!s->bitmap && !nothing && !s->cancelled) { 1141 error_report("Error: block device name is not set"); 1142 cancel_incoming_locked(s); 1143 } 1144 1145 return 0; 1146 } 1147 1148 /* 1149 * dirty_bitmap_load 1150 * 1151 * Load sequence of dirty bitmap chunks. Return error only on fatal io stream 1152 * violations. On other errors just cancel bitmaps incoming migration and return 1153 * 0. 1154 * 1155 * Note, than when incoming bitmap migration is canceled, we still must read all 1156 * our chunks (and just ignore them), to not affect other migration objects. 1157 */ 1158 static int dirty_bitmap_load(QEMUFile *f, void *opaque, int version_id) 1159 { 1160 GHashTable *alias_map = NULL; 1161 const MigrationParameters *mig_params = &migrate_get_current()->parameters; 1162 DBMLoadState *s = &((DBMState *)opaque)->load; 1163 int ret = 0; 1164 1165 trace_dirty_bitmap_load_enter(); 1166 1167 if (version_id != 1) { 1168 QEMU_LOCK_GUARD(&s->lock); 1169 cancel_incoming_locked(s); 1170 return -EINVAL; 1171 } 1172 1173 if (mig_params->has_block_bitmap_mapping) { 1174 alias_map = construct_alias_map(mig_params->block_bitmap_mapping, 1175 false, &error_abort); 1176 } 1177 1178 do { 1179 QEMU_LOCK_GUARD(&s->lock); 1180 1181 ret = dirty_bitmap_load_header(f, s, alias_map); 1182 if (ret < 0) { 1183 cancel_incoming_locked(s); 1184 goto fail; 1185 } 1186 1187 if (s->flags & DIRTY_BITMAP_MIG_FLAG_START) { 1188 ret = dirty_bitmap_load_start(f, s); 1189 } else if (s->flags & DIRTY_BITMAP_MIG_FLAG_COMPLETE) { 1190 dirty_bitmap_load_complete(f, s); 1191 } else if (s->flags & DIRTY_BITMAP_MIG_FLAG_BITS) { 1192 ret = dirty_bitmap_load_bits(f, s); 1193 } 1194 1195 if (!ret) { 1196 ret = qemu_file_get_error(f); 1197 } 1198 1199 if (ret) { 1200 cancel_incoming_locked(s); 1201 goto fail; 1202 } 1203 } while (!(s->flags & DIRTY_BITMAP_MIG_FLAG_EOS)); 1204 1205 trace_dirty_bitmap_load_success(); 1206 ret = 0; 1207 fail: 1208 if (alias_map) { 1209 g_hash_table_destroy(alias_map); 1210 } 1211 return ret; 1212 } 1213 1214 static int dirty_bitmap_save_setup(QEMUFile *f, void *opaque) 1215 { 1216 DBMSaveState *s = &((DBMState *)opaque)->save; 1217 SaveBitmapState *dbms = NULL; 1218 1219 qemu_mutex_lock_iothread(); 1220 if (init_dirty_bitmap_migration(s) < 0) { 1221 qemu_mutex_unlock_iothread(); 1222 return -1; 1223 } 1224 1225 QSIMPLEQ_FOREACH(dbms, &s->dbms_list, entry) { 1226 send_bitmap_start(f, s, dbms); 1227 } 1228 qemu_put_bitmap_flags(f, DIRTY_BITMAP_MIG_FLAG_EOS); 1229 qemu_mutex_unlock_iothread(); 1230 return 0; 1231 } 1232 1233 static bool dirty_bitmap_is_active(void *opaque) 1234 { 1235 DBMSaveState *s = &((DBMState *)opaque)->save; 1236 1237 return migrate_dirty_bitmaps() && !s->no_bitmaps; 1238 } 1239 1240 static bool dirty_bitmap_is_active_iterate(void *opaque) 1241 { 1242 return dirty_bitmap_is_active(opaque) && !runstate_is_running(); 1243 } 1244 1245 static bool dirty_bitmap_has_postcopy(void *opaque) 1246 { 1247 return true; 1248 } 1249 1250 static SaveVMHandlers savevm_dirty_bitmap_handlers = { 1251 .save_setup = dirty_bitmap_save_setup, 1252 .save_live_complete_postcopy = dirty_bitmap_save_complete, 1253 .save_live_complete_precopy = dirty_bitmap_save_complete, 1254 .has_postcopy = dirty_bitmap_has_postcopy, 1255 .save_live_pending = dirty_bitmap_save_pending, 1256 .save_live_iterate = dirty_bitmap_save_iterate, 1257 .is_active_iterate = dirty_bitmap_is_active_iterate, 1258 .load_state = dirty_bitmap_load, 1259 .save_cleanup = dirty_bitmap_save_cleanup, 1260 .is_active = dirty_bitmap_is_active, 1261 }; 1262 1263 void dirty_bitmap_mig_init(void) 1264 { 1265 QSIMPLEQ_INIT(&dbm_state.save.dbms_list); 1266 qemu_mutex_init(&dbm_state.load.lock); 1267 1268 register_savevm_live("dirty-bitmap", 0, 1, 1269 &savevm_dirty_bitmap_handlers, 1270 &dbm_state); 1271 } 1272