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 name size ] \ flags & DEVICE_NAME 33 * [ n bytes: node name ] / 34 * [ 1 byte: bitmap name size ] \ flags & BITMAP_NAME 35 * [ n bytes: bitmap name ] / 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 "qemu/main-loop.h" 66 #include "qemu/error-report.h" 67 #include "migration/misc.h" 68 #include "migration/migration.h" 69 #include "migration/qemu-file.h" 70 #include "migration/vmstate.h" 71 #include "migration/register.h" 72 #include "qemu/hbitmap.h" 73 #include "sysemu/sysemu.h" 74 #include "qemu/cutils.h" 75 #include "qapi/error.h" 76 #include "trace.h" 77 78 #define CHUNK_SIZE (1 << 10) 79 80 /* Flags occupy one, two or four bytes (Big Endian). The size is determined as 81 * follows: 82 * in first (most significant) byte bit 8 is clear --> one byte 83 * in first byte bit 8 is set --> two or four bytes, depending on second 84 * byte: 85 * | in second byte bit 8 is clear --> two bytes 86 * | in second byte bit 8 is set --> four bytes 87 */ 88 #define DIRTY_BITMAP_MIG_FLAG_EOS 0x01 89 #define DIRTY_BITMAP_MIG_FLAG_ZEROES 0x02 90 #define DIRTY_BITMAP_MIG_FLAG_BITMAP_NAME 0x04 91 #define DIRTY_BITMAP_MIG_FLAG_DEVICE_NAME 0x08 92 #define DIRTY_BITMAP_MIG_FLAG_START 0x10 93 #define DIRTY_BITMAP_MIG_FLAG_COMPLETE 0x20 94 #define DIRTY_BITMAP_MIG_FLAG_BITS 0x40 95 96 #define DIRTY_BITMAP_MIG_EXTRA_FLAGS 0x80 97 98 #define DIRTY_BITMAP_MIG_START_FLAG_ENABLED 0x01 99 #define DIRTY_BITMAP_MIG_START_FLAG_PERSISTENT 0x02 100 /* 0x04 was "AUTOLOAD" flags on elder versions, no it is ignored */ 101 #define DIRTY_BITMAP_MIG_START_FLAG_RESERVED_MASK 0xf8 102 103 typedef struct DirtyBitmapMigBitmapState { 104 /* Written during setup phase. */ 105 BlockDriverState *bs; 106 const char *node_name; 107 BdrvDirtyBitmap *bitmap; 108 uint64_t total_sectors; 109 uint64_t sectors_per_chunk; 110 QSIMPLEQ_ENTRY(DirtyBitmapMigBitmapState) entry; 111 uint8_t flags; 112 113 /* For bulk phase. */ 114 bool bulk_completed; 115 uint64_t cur_sector; 116 } DirtyBitmapMigBitmapState; 117 118 typedef struct DirtyBitmapMigState { 119 QSIMPLEQ_HEAD(dbms_list, DirtyBitmapMigBitmapState) dbms_list; 120 121 bool bulk_completed; 122 bool no_bitmaps; 123 124 /* for send_bitmap_bits() */ 125 BlockDriverState *prev_bs; 126 BdrvDirtyBitmap *prev_bitmap; 127 } DirtyBitmapMigState; 128 129 typedef struct DirtyBitmapLoadState { 130 uint32_t flags; 131 char node_name[256]; 132 char bitmap_name[256]; 133 BlockDriverState *bs; 134 BdrvDirtyBitmap *bitmap; 135 } DirtyBitmapLoadState; 136 137 static DirtyBitmapMigState dirty_bitmap_mig_state; 138 139 typedef struct DirtyBitmapLoadBitmapState { 140 BlockDriverState *bs; 141 BdrvDirtyBitmap *bitmap; 142 bool migrated; 143 } DirtyBitmapLoadBitmapState; 144 static GSList *enabled_bitmaps; 145 QemuMutex finish_lock; 146 147 void init_dirty_bitmap_incoming_migration(void) 148 { 149 qemu_mutex_init(&finish_lock); 150 } 151 152 static uint32_t qemu_get_bitmap_flags(QEMUFile *f) 153 { 154 uint8_t flags = qemu_get_byte(f); 155 if (flags & DIRTY_BITMAP_MIG_EXTRA_FLAGS) { 156 flags = flags << 8 | qemu_get_byte(f); 157 if (flags & DIRTY_BITMAP_MIG_EXTRA_FLAGS) { 158 flags = flags << 16 | qemu_get_be16(f); 159 } 160 } 161 162 return flags; 163 } 164 165 static void qemu_put_bitmap_flags(QEMUFile *f, uint32_t flags) 166 { 167 /* The code currently do not send flags more than one byte */ 168 assert(!(flags & (0xffffff00 | DIRTY_BITMAP_MIG_EXTRA_FLAGS))); 169 170 qemu_put_byte(f, flags); 171 } 172 173 static void send_bitmap_header(QEMUFile *f, DirtyBitmapMigBitmapState *dbms, 174 uint32_t additional_flags) 175 { 176 BlockDriverState *bs = dbms->bs; 177 BdrvDirtyBitmap *bitmap = dbms->bitmap; 178 uint32_t flags = additional_flags; 179 trace_send_bitmap_header_enter(); 180 181 if (bs != dirty_bitmap_mig_state.prev_bs) { 182 dirty_bitmap_mig_state.prev_bs = bs; 183 flags |= DIRTY_BITMAP_MIG_FLAG_DEVICE_NAME; 184 } 185 186 if (bitmap != dirty_bitmap_mig_state.prev_bitmap) { 187 dirty_bitmap_mig_state.prev_bitmap = bitmap; 188 flags |= DIRTY_BITMAP_MIG_FLAG_BITMAP_NAME; 189 } 190 191 qemu_put_bitmap_flags(f, flags); 192 193 if (flags & DIRTY_BITMAP_MIG_FLAG_DEVICE_NAME) { 194 qemu_put_counted_string(f, dbms->node_name); 195 } 196 197 if (flags & DIRTY_BITMAP_MIG_FLAG_BITMAP_NAME) { 198 qemu_put_counted_string(f, bdrv_dirty_bitmap_name(bitmap)); 199 } 200 } 201 202 static void send_bitmap_start(QEMUFile *f, DirtyBitmapMigBitmapState *dbms) 203 { 204 send_bitmap_header(f, dbms, DIRTY_BITMAP_MIG_FLAG_START); 205 qemu_put_be32(f, bdrv_dirty_bitmap_granularity(dbms->bitmap)); 206 qemu_put_byte(f, dbms->flags); 207 } 208 209 static void send_bitmap_complete(QEMUFile *f, DirtyBitmapMigBitmapState *dbms) 210 { 211 send_bitmap_header(f, dbms, DIRTY_BITMAP_MIG_FLAG_COMPLETE); 212 } 213 214 static void send_bitmap_bits(QEMUFile *f, DirtyBitmapMigBitmapState *dbms, 215 uint64_t start_sector, uint32_t nr_sectors) 216 { 217 /* align for buffer_is_zero() */ 218 uint64_t align = 4 * sizeof(long); 219 uint64_t unaligned_size = 220 bdrv_dirty_bitmap_serialization_size( 221 dbms->bitmap, start_sector << BDRV_SECTOR_BITS, 222 (uint64_t)nr_sectors << BDRV_SECTOR_BITS); 223 uint64_t buf_size = QEMU_ALIGN_UP(unaligned_size, align); 224 uint8_t *buf = g_malloc0(buf_size); 225 uint32_t flags = DIRTY_BITMAP_MIG_FLAG_BITS; 226 227 bdrv_dirty_bitmap_serialize_part( 228 dbms->bitmap, buf, start_sector << BDRV_SECTOR_BITS, 229 (uint64_t)nr_sectors << BDRV_SECTOR_BITS); 230 231 if (buffer_is_zero(buf, buf_size)) { 232 g_free(buf); 233 buf = NULL; 234 flags |= DIRTY_BITMAP_MIG_FLAG_ZEROES; 235 } 236 237 trace_send_bitmap_bits(flags, start_sector, nr_sectors, buf_size); 238 239 send_bitmap_header(f, dbms, flags); 240 241 qemu_put_be64(f, start_sector); 242 qemu_put_be32(f, nr_sectors); 243 244 /* if a block is zero we need to flush here since the network 245 * bandwidth is now a lot higher than the storage device bandwidth. 246 * thus if we queue zero blocks we slow down the migration. */ 247 if (flags & DIRTY_BITMAP_MIG_FLAG_ZEROES) { 248 qemu_fflush(f); 249 } else { 250 qemu_put_be64(f, buf_size); 251 qemu_put_buffer(f, buf, buf_size); 252 } 253 254 g_free(buf); 255 } 256 257 /* Called with iothread lock taken. */ 258 static void dirty_bitmap_mig_cleanup(void) 259 { 260 DirtyBitmapMigBitmapState *dbms; 261 262 while ((dbms = QSIMPLEQ_FIRST(&dirty_bitmap_mig_state.dbms_list)) != NULL) { 263 QSIMPLEQ_REMOVE_HEAD(&dirty_bitmap_mig_state.dbms_list, entry); 264 bdrv_dirty_bitmap_set_qmp_locked(dbms->bitmap, false); 265 bdrv_unref(dbms->bs); 266 g_free(dbms); 267 } 268 } 269 270 /* Called with iothread lock taken. */ 271 static int init_dirty_bitmap_migration(void) 272 { 273 BlockDriverState *bs; 274 BdrvDirtyBitmap *bitmap; 275 DirtyBitmapMigBitmapState *dbms; 276 BdrvNextIterator it; 277 278 dirty_bitmap_mig_state.bulk_completed = false; 279 dirty_bitmap_mig_state.prev_bs = NULL; 280 dirty_bitmap_mig_state.prev_bitmap = NULL; 281 dirty_bitmap_mig_state.no_bitmaps = false; 282 283 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { 284 const char *drive_name = bdrv_get_device_or_node_name(bs); 285 286 /* skip automatically inserted nodes */ 287 while (bs && bs->drv && bs->implicit) { 288 bs = backing_bs(bs); 289 } 290 291 for (bitmap = bdrv_dirty_bitmap_next(bs, NULL); bitmap; 292 bitmap = bdrv_dirty_bitmap_next(bs, bitmap)) 293 { 294 if (!bdrv_dirty_bitmap_name(bitmap)) { 295 continue; 296 } 297 298 if (drive_name == NULL) { 299 error_report("Found bitmap '%s' in unnamed node %p. It can't " 300 "be migrated", bdrv_dirty_bitmap_name(bitmap), bs); 301 goto fail; 302 } 303 304 if (bdrv_dirty_bitmap_frozen(bitmap)) { 305 error_report("Can't migrate frozen dirty bitmap: '%s", 306 bdrv_dirty_bitmap_name(bitmap)); 307 goto fail; 308 } 309 310 if (bdrv_dirty_bitmap_qmp_locked(bitmap)) { 311 error_report("Can't migrate locked dirty bitmap: '%s", 312 bdrv_dirty_bitmap_name(bitmap)); 313 goto fail; 314 } 315 316 bdrv_ref(bs); 317 bdrv_dirty_bitmap_set_qmp_locked(bitmap, true); 318 319 dbms = g_new0(DirtyBitmapMigBitmapState, 1); 320 dbms->bs = bs; 321 dbms->node_name = drive_name; 322 dbms->bitmap = bitmap; 323 dbms->total_sectors = bdrv_nb_sectors(bs); 324 dbms->sectors_per_chunk = CHUNK_SIZE * 8 * 325 bdrv_dirty_bitmap_granularity(bitmap) >> BDRV_SECTOR_BITS; 326 if (bdrv_dirty_bitmap_enabled(bitmap)) { 327 dbms->flags |= DIRTY_BITMAP_MIG_START_FLAG_ENABLED; 328 } 329 if (bdrv_dirty_bitmap_get_persistance(bitmap)) { 330 dbms->flags |= DIRTY_BITMAP_MIG_START_FLAG_PERSISTENT; 331 } 332 333 QSIMPLEQ_INSERT_TAIL(&dirty_bitmap_mig_state.dbms_list, 334 dbms, entry); 335 } 336 } 337 338 /* unset persistance here, to not roll back it */ 339 QSIMPLEQ_FOREACH(dbms, &dirty_bitmap_mig_state.dbms_list, entry) { 340 bdrv_dirty_bitmap_set_persistance(dbms->bitmap, false); 341 } 342 343 if (QSIMPLEQ_EMPTY(&dirty_bitmap_mig_state.dbms_list)) { 344 dirty_bitmap_mig_state.no_bitmaps = true; 345 } 346 347 return 0; 348 349 fail: 350 dirty_bitmap_mig_cleanup(); 351 352 return -1; 353 } 354 355 /* Called with no lock taken. */ 356 static void bulk_phase_send_chunk(QEMUFile *f, DirtyBitmapMigBitmapState *dbms) 357 { 358 uint32_t nr_sectors = MIN(dbms->total_sectors - dbms->cur_sector, 359 dbms->sectors_per_chunk); 360 361 send_bitmap_bits(f, dbms, dbms->cur_sector, nr_sectors); 362 363 dbms->cur_sector += nr_sectors; 364 if (dbms->cur_sector >= dbms->total_sectors) { 365 dbms->bulk_completed = true; 366 } 367 } 368 369 /* Called with no lock taken. */ 370 static void bulk_phase(QEMUFile *f, bool limit) 371 { 372 DirtyBitmapMigBitmapState *dbms; 373 374 QSIMPLEQ_FOREACH(dbms, &dirty_bitmap_mig_state.dbms_list, entry) { 375 while (!dbms->bulk_completed) { 376 bulk_phase_send_chunk(f, dbms); 377 if (limit && qemu_file_rate_limit(f)) { 378 return; 379 } 380 } 381 } 382 383 dirty_bitmap_mig_state.bulk_completed = true; 384 } 385 386 /* for SaveVMHandlers */ 387 static void dirty_bitmap_save_cleanup(void *opaque) 388 { 389 dirty_bitmap_mig_cleanup(); 390 } 391 392 static int dirty_bitmap_save_iterate(QEMUFile *f, void *opaque) 393 { 394 trace_dirty_bitmap_save_iterate(migration_in_postcopy()); 395 396 if (migration_in_postcopy() && !dirty_bitmap_mig_state.bulk_completed) { 397 bulk_phase(f, true); 398 } 399 400 qemu_put_bitmap_flags(f, DIRTY_BITMAP_MIG_FLAG_EOS); 401 402 return dirty_bitmap_mig_state.bulk_completed; 403 } 404 405 /* Called with iothread lock taken. */ 406 407 static int dirty_bitmap_save_complete(QEMUFile *f, void *opaque) 408 { 409 DirtyBitmapMigBitmapState *dbms; 410 trace_dirty_bitmap_save_complete_enter(); 411 412 if (!dirty_bitmap_mig_state.bulk_completed) { 413 bulk_phase(f, false); 414 } 415 416 QSIMPLEQ_FOREACH(dbms, &dirty_bitmap_mig_state.dbms_list, entry) { 417 send_bitmap_complete(f, dbms); 418 } 419 420 qemu_put_bitmap_flags(f, DIRTY_BITMAP_MIG_FLAG_EOS); 421 422 trace_dirty_bitmap_save_complete_finish(); 423 424 dirty_bitmap_mig_cleanup(); 425 return 0; 426 } 427 428 static void dirty_bitmap_save_pending(QEMUFile *f, void *opaque, 429 uint64_t max_size, 430 uint64_t *res_precopy_only, 431 uint64_t *res_compatible, 432 uint64_t *res_postcopy_only) 433 { 434 DirtyBitmapMigBitmapState *dbms; 435 uint64_t pending = 0; 436 437 qemu_mutex_lock_iothread(); 438 439 QSIMPLEQ_FOREACH(dbms, &dirty_bitmap_mig_state.dbms_list, entry) { 440 uint64_t gran = bdrv_dirty_bitmap_granularity(dbms->bitmap); 441 uint64_t sectors = dbms->bulk_completed ? 0 : 442 dbms->total_sectors - dbms->cur_sector; 443 444 pending += DIV_ROUND_UP(sectors * BDRV_SECTOR_SIZE, gran); 445 } 446 447 qemu_mutex_unlock_iothread(); 448 449 trace_dirty_bitmap_save_pending(pending, max_size); 450 451 *res_postcopy_only += pending; 452 } 453 454 /* First occurrence of this bitmap. It should be created if doesn't exist */ 455 static int dirty_bitmap_load_start(QEMUFile *f, DirtyBitmapLoadState *s) 456 { 457 Error *local_err = NULL; 458 uint32_t granularity = qemu_get_be32(f); 459 uint8_t flags = qemu_get_byte(f); 460 461 if (s->bitmap) { 462 error_report("Bitmap with the same name ('%s') already exists on " 463 "destination", bdrv_dirty_bitmap_name(s->bitmap)); 464 return -EINVAL; 465 } else { 466 s->bitmap = bdrv_create_dirty_bitmap(s->bs, granularity, 467 s->bitmap_name, &local_err); 468 if (!s->bitmap) { 469 error_report_err(local_err); 470 return -EINVAL; 471 } 472 } 473 474 if (flags & DIRTY_BITMAP_MIG_START_FLAG_RESERVED_MASK) { 475 error_report("Unknown flags in migrated dirty bitmap header: %x", 476 flags); 477 return -EINVAL; 478 } 479 480 if (flags & DIRTY_BITMAP_MIG_START_FLAG_PERSISTENT) { 481 bdrv_dirty_bitmap_set_persistance(s->bitmap, true); 482 } 483 484 bdrv_disable_dirty_bitmap(s->bitmap); 485 if (flags & DIRTY_BITMAP_MIG_START_FLAG_ENABLED) { 486 DirtyBitmapLoadBitmapState *b; 487 488 bdrv_dirty_bitmap_create_successor(s->bs, s->bitmap, &local_err); 489 if (local_err) { 490 error_report_err(local_err); 491 return -EINVAL; 492 } 493 494 b = g_new(DirtyBitmapLoadBitmapState, 1); 495 b->bs = s->bs; 496 b->bitmap = s->bitmap; 497 b->migrated = false; 498 enabled_bitmaps = g_slist_prepend(enabled_bitmaps, b); 499 } 500 501 return 0; 502 } 503 504 void dirty_bitmap_mig_before_vm_start(void) 505 { 506 GSList *item; 507 508 qemu_mutex_lock(&finish_lock); 509 510 for (item = enabled_bitmaps; item; item = g_slist_next(item)) { 511 DirtyBitmapLoadBitmapState *b = item->data; 512 513 if (b->migrated) { 514 bdrv_enable_dirty_bitmap(b->bitmap); 515 } else { 516 bdrv_dirty_bitmap_enable_successor(b->bitmap); 517 } 518 519 g_free(b); 520 } 521 522 g_slist_free(enabled_bitmaps); 523 enabled_bitmaps = NULL; 524 525 qemu_mutex_unlock(&finish_lock); 526 } 527 528 static void dirty_bitmap_load_complete(QEMUFile *f, DirtyBitmapLoadState *s) 529 { 530 GSList *item; 531 trace_dirty_bitmap_load_complete(); 532 bdrv_dirty_bitmap_deserialize_finish(s->bitmap); 533 534 qemu_mutex_lock(&finish_lock); 535 536 for (item = enabled_bitmaps; item; item = g_slist_next(item)) { 537 DirtyBitmapLoadBitmapState *b = item->data; 538 539 if (b->bitmap == s->bitmap) { 540 b->migrated = true; 541 break; 542 } 543 } 544 545 if (bdrv_dirty_bitmap_frozen(s->bitmap)) { 546 bdrv_dirty_bitmap_lock(s->bitmap); 547 if (enabled_bitmaps == NULL) { 548 /* in postcopy */ 549 bdrv_reclaim_dirty_bitmap_locked(s->bs, s->bitmap, &error_abort); 550 bdrv_enable_dirty_bitmap(s->bitmap); 551 } else { 552 /* target not started, successor must be empty */ 553 int64_t count = bdrv_get_dirty_count(s->bitmap); 554 BdrvDirtyBitmap *ret = bdrv_reclaim_dirty_bitmap_locked(s->bs, 555 s->bitmap, 556 NULL); 557 /* bdrv_reclaim_dirty_bitmap can fail only on no successor (it 558 * must be) or on merge fail, but merge can't fail when second 559 * bitmap is empty 560 */ 561 assert(ret == s->bitmap && 562 count == bdrv_get_dirty_count(s->bitmap)); 563 } 564 bdrv_dirty_bitmap_unlock(s->bitmap); 565 } 566 567 qemu_mutex_unlock(&finish_lock); 568 } 569 570 static int dirty_bitmap_load_bits(QEMUFile *f, DirtyBitmapLoadState *s) 571 { 572 uint64_t first_byte = qemu_get_be64(f) << BDRV_SECTOR_BITS; 573 uint64_t nr_bytes = (uint64_t)qemu_get_be32(f) << BDRV_SECTOR_BITS; 574 trace_dirty_bitmap_load_bits_enter(first_byte >> BDRV_SECTOR_BITS, 575 nr_bytes >> BDRV_SECTOR_BITS); 576 577 if (s->flags & DIRTY_BITMAP_MIG_FLAG_ZEROES) { 578 trace_dirty_bitmap_load_bits_zeroes(); 579 bdrv_dirty_bitmap_deserialize_zeroes(s->bitmap, first_byte, nr_bytes, 580 false); 581 } else { 582 size_t ret; 583 uint8_t *buf; 584 uint64_t buf_size = qemu_get_be64(f); 585 uint64_t needed_size = 586 bdrv_dirty_bitmap_serialization_size(s->bitmap, 587 first_byte, nr_bytes); 588 589 if (needed_size > buf_size || 590 buf_size > QEMU_ALIGN_UP(needed_size, 4 * sizeof(long)) 591 /* Here used same alignment as in send_bitmap_bits */ 592 ) { 593 error_report("Migrated bitmap granularity doesn't " 594 "match the destination bitmap '%s' granularity", 595 bdrv_dirty_bitmap_name(s->bitmap)); 596 return -EINVAL; 597 } 598 599 buf = g_malloc(buf_size); 600 ret = qemu_get_buffer(f, buf, buf_size); 601 if (ret != buf_size) { 602 error_report("Failed to read bitmap bits"); 603 return -EIO; 604 } 605 606 bdrv_dirty_bitmap_deserialize_part(s->bitmap, buf, first_byte, nr_bytes, 607 false); 608 g_free(buf); 609 } 610 611 return 0; 612 } 613 614 static int dirty_bitmap_load_header(QEMUFile *f, DirtyBitmapLoadState *s) 615 { 616 Error *local_err = NULL; 617 bool nothing; 618 s->flags = qemu_get_bitmap_flags(f); 619 trace_dirty_bitmap_load_header(s->flags); 620 621 nothing = s->flags == (s->flags & DIRTY_BITMAP_MIG_FLAG_EOS); 622 623 if (s->flags & DIRTY_BITMAP_MIG_FLAG_DEVICE_NAME) { 624 if (!qemu_get_counted_string(f, s->node_name)) { 625 error_report("Unable to read node name string"); 626 return -EINVAL; 627 } 628 s->bs = bdrv_lookup_bs(s->node_name, s->node_name, &local_err); 629 if (!s->bs) { 630 error_report_err(local_err); 631 return -EINVAL; 632 } 633 } else if (!s->bs && !nothing) { 634 error_report("Error: block device name is not set"); 635 return -EINVAL; 636 } 637 638 if (s->flags & DIRTY_BITMAP_MIG_FLAG_BITMAP_NAME) { 639 if (!qemu_get_counted_string(f, s->bitmap_name)) { 640 error_report("Unable to read bitmap name string"); 641 return -EINVAL; 642 } 643 s->bitmap = bdrv_find_dirty_bitmap(s->bs, s->bitmap_name); 644 645 /* bitmap may be NULL here, it wouldn't be an error if it is the 646 * first occurrence of the bitmap */ 647 if (!s->bitmap && !(s->flags & DIRTY_BITMAP_MIG_FLAG_START)) { 648 error_report("Error: unknown dirty bitmap " 649 "'%s' for block device '%s'", 650 s->bitmap_name, s->node_name); 651 return -EINVAL; 652 } 653 } else if (!s->bitmap && !nothing) { 654 error_report("Error: block device name is not set"); 655 return -EINVAL; 656 } 657 658 return 0; 659 } 660 661 static int dirty_bitmap_load(QEMUFile *f, void *opaque, int version_id) 662 { 663 static DirtyBitmapLoadState s; 664 int ret = 0; 665 666 trace_dirty_bitmap_load_enter(); 667 668 if (version_id != 1) { 669 return -EINVAL; 670 } 671 672 do { 673 ret = dirty_bitmap_load_header(f, &s); 674 675 if (s.flags & DIRTY_BITMAP_MIG_FLAG_START) { 676 ret = dirty_bitmap_load_start(f, &s); 677 } else if (s.flags & DIRTY_BITMAP_MIG_FLAG_COMPLETE) { 678 dirty_bitmap_load_complete(f, &s); 679 } else if (s.flags & DIRTY_BITMAP_MIG_FLAG_BITS) { 680 ret = dirty_bitmap_load_bits(f, &s); 681 } 682 683 if (!ret) { 684 ret = qemu_file_get_error(f); 685 } 686 687 if (ret) { 688 return ret; 689 } 690 } while (!(s.flags & DIRTY_BITMAP_MIG_FLAG_EOS)); 691 692 trace_dirty_bitmap_load_success(); 693 return 0; 694 } 695 696 static int dirty_bitmap_save_setup(QEMUFile *f, void *opaque) 697 { 698 DirtyBitmapMigBitmapState *dbms = NULL; 699 if (init_dirty_bitmap_migration() < 0) { 700 return -1; 701 } 702 703 QSIMPLEQ_FOREACH(dbms, &dirty_bitmap_mig_state.dbms_list, entry) { 704 send_bitmap_start(f, dbms); 705 } 706 qemu_put_bitmap_flags(f, DIRTY_BITMAP_MIG_FLAG_EOS); 707 708 return 0; 709 } 710 711 static bool dirty_bitmap_is_active(void *opaque) 712 { 713 return migrate_dirty_bitmaps() && !dirty_bitmap_mig_state.no_bitmaps; 714 } 715 716 static bool dirty_bitmap_is_active_iterate(void *opaque) 717 { 718 return dirty_bitmap_is_active(opaque) && !runstate_is_running(); 719 } 720 721 static bool dirty_bitmap_has_postcopy(void *opaque) 722 { 723 return true; 724 } 725 726 static SaveVMHandlers savevm_dirty_bitmap_handlers = { 727 .save_setup = dirty_bitmap_save_setup, 728 .save_live_complete_postcopy = dirty_bitmap_save_complete, 729 .save_live_complete_precopy = dirty_bitmap_save_complete, 730 .has_postcopy = dirty_bitmap_has_postcopy, 731 .save_live_pending = dirty_bitmap_save_pending, 732 .save_live_iterate = dirty_bitmap_save_iterate, 733 .is_active_iterate = dirty_bitmap_is_active_iterate, 734 .load_state = dirty_bitmap_load, 735 .save_cleanup = dirty_bitmap_save_cleanup, 736 .is_active = dirty_bitmap_is_active, 737 }; 738 739 void dirty_bitmap_mig_init(void) 740 { 741 QSIMPLEQ_INIT(&dirty_bitmap_mig_state.dbms_list); 742 743 register_savevm_live(NULL, "dirty-bitmap", 0, 1, 744 &savevm_dirty_bitmap_handlers, 745 &dirty_bitmap_mig_state); 746 } 747