block-migration.c

   1 /*
   2  * QEMU live block migration
   3  *
   4  * Copyright IBM, Corp. 2009
   5  *
   6  * Authors:
   7  *  Liran Schour   <[email protected]>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2.  See
  10  * the COPYING file in the top-level directory.
  11  *
  12  * Contributions after 2012-01-13 are licensed under the terms of the
  13  * GNU GPL, version 2 or (at your option) any later version.
  14  */
  15
  16 #include "qemu-common.h"
  17 #include "block/block_int.h"
  18 #include "hw/hw.h"
  19 #include "qemu/queue.h"
  20 #include "qemu/timer.h"
  21 #include "migration/block.h"
  22 #include "migration/migration.h"
  23 #include "sysemu/blockdev.h"
  24 #include <assert.h>
  25
  26 #define BLOCK_SIZE (BDRV_SECTORS_PER_DIRTY_CHUNK << BDRV_SECTOR_BITS)
  27
  28 #define BLK_MIG_FLAG_DEVICE_BLOCK       0x01
  29 #define BLK_MIG_FLAG_EOS                0x02
  30 #define BLK_MIG_FLAG_PROGRESS           0x04
  31
  32 #define MAX_IS_ALLOCATED_SEARCH 65536
  33
  34 //#define DEBUG_BLK_MIGRATION
  35
  36 #ifdef DEBUG_BLK_MIGRATION
  37 #define DPRINTF(fmt, ...) \
  38     do { printf("blk_migration: " fmt, ## __VA_ARGS__); } while (0)
  39 #else
  40 #define DPRINTF(fmt, ...) \
  41     do { } while (0)
  42 #endif
  43
  44 typedef struct BlkMigDevState {
  45     BlockDriverState *bs;
  46     int bulk_completed;
  47     int shared_base;
  48     int64_t cur_sector;
  49     int64_t cur_dirty;
  50     int64_t completed_sectors;
  51     int64_t total_sectors;
  52     int64_t dirty;
  53     QSIMPLEQ_ENTRY(BlkMigDevState) entry;
  54     unsigned long *aio_bitmap;
  55 } BlkMigDevState;
  56
  57 typedef struct BlkMigBlock {
  58     uint8_t *buf;
  59     BlkMigDevState *bmds;
  60     int64_t sector;
  61     int nr_sectors;
  62     struct iovec iov;
  63     QEMUIOVector qiov;
  64     BlockDriverAIOCB *aiocb;
  65     int ret;
  66     QSIMPLEQ_ENTRY(BlkMigBlock) entry;
  67 } BlkMigBlock;
  68
  69 typedef struct BlkMigState {
  70     int blk_enable;
  71     int shared_base;
  72     QSIMPLEQ_HEAD(bmds_list, BlkMigDevState) bmds_list;
  73     QSIMPLEQ_HEAD(blk_list, BlkMigBlock) blk_list;
  74     int submitted;
  75     int read_done;
  76     int transferred;
  77     int64_t total_sector_sum;
  78     int prev_progress;
  79     int bulk_completed;
  80     long double prev_time_offset;
  81 } BlkMigState;
  82
  83 static BlkMigState block_mig_state;
  84
  85 static void blk_send(QEMUFile *f, BlkMigBlock * blk)
  86 {
  87     int len;
  88
  89     /* sector number and flags */
  90     qemu_put_be64(f, (blk->sector << BDRV_SECTOR_BITS)
  91                      | BLK_MIG_FLAG_DEVICE_BLOCK);
  92
  93     /* device name */
  94     len = strlen(blk->bmds->bs->device_name);
  95     qemu_put_byte(f, len);
  96     qemu_put_buffer(f, (uint8_t *)blk->bmds->bs->device_name, len);
  97
  98     qemu_put_buffer(f, blk->buf, BLOCK_SIZE);
  99 }
 100
 101 int blk_mig_active(void)
 102 {
 103     return !QSIMPLEQ_EMPTY(&block_mig_state.bmds_list);
 104 }
 105
 106 uint64_t blk_mig_bytes_transferred(void)
 107 {
 108     BlkMigDevState *bmds;
 109     uint64_t sum = 0;
 110
 111     QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
 112         sum += bmds->completed_sectors;
 113     }
 114     return sum << BDRV_SECTOR_BITS;
 115 }
 116
 117 uint64_t blk_mig_bytes_remaining(void)
 118 {
 119     return blk_mig_bytes_total() - blk_mig_bytes_transferred();
 120 }
 121
 122 uint64_t blk_mig_bytes_total(void)
 123 {
 124     BlkMigDevState *bmds;
 125     uint64_t sum = 0;
 126
 127     QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
 128         sum += bmds->total_sectors;
 129     }
 130     return sum << BDRV_SECTOR_BITS;
 131 }
 132
 133 static int bmds_aio_inflight(BlkMigDevState *bmds, int64_t sector)
 134 {
 135     int64_t chunk = sector / (int64_t)BDRV_SECTORS_PER_DIRTY_CHUNK;
 136
 137     if ((sector << BDRV_SECTOR_BITS) < bdrv_getlength(bmds->bs)) {
 138         return !!(bmds->aio_bitmap[chunk / (sizeof(unsigned long) * 8)] &
 139             (1UL << (chunk % (sizeof(unsigned long) * 8))));
 140     } else {
 141         return 0;
 142     }
 143 }
 144
 145 static void bmds_set_aio_inflight(BlkMigDevState *bmds, int64_t sector_num,
 146                              int nb_sectors, int set)
 147 {
 148     int64_t start, end;
 149     unsigned long val, idx, bit;
 150
 151     start = sector_num / BDRV_SECTORS_PER_DIRTY_CHUNK;
 152     end = (sector_num + nb_sectors - 1) / BDRV_SECTORS_PER_DIRTY_CHUNK;
 153
 154     for (; start <= end; start++) {
 155         idx = start / (sizeof(unsigned long) * 8);
 156         bit = start % (sizeof(unsigned long) * 8);
 157         val = bmds->aio_bitmap[idx];
 158         if (set) {
 159             val |= 1UL << bit;
 160         } else {
 161             val &= ~(1UL << bit);
 162         }
 163         bmds->aio_bitmap[idx] = val;
 164     }
 165 }
 166
 167 static void alloc_aio_bitmap(BlkMigDevState *bmds)
 168 {
 169     BlockDriverState *bs = bmds->bs;
 170     int64_t bitmap_size;
 171
 172     bitmap_size = (bdrv_getlength(bs) >> BDRV_SECTOR_BITS) +
 173             BDRV_SECTORS_PER_DIRTY_CHUNK * 8 - 1;
 174     bitmap_size /= BDRV_SECTORS_PER_DIRTY_CHUNK * 8;
 175
 176     bmds->aio_bitmap = g_malloc0(bitmap_size);
 177 }
 178
 179 static void blk_mig_read_cb(void *opaque, int ret)
 180 {
 181     long double curr_time = qemu_get_clock_ns(rt_clock);
 182     BlkMigBlock *blk = opaque;
 183
 184     blk->ret = ret;
 185
 186     block_mig_state.prev_time_offset = curr_time;
 187
 188     QSIMPLEQ_INSERT_TAIL(&block_mig_state.blk_list, blk, entry);
 189     bmds_set_aio_inflight(blk->bmds, blk->sector, blk->nr_sectors, 0);
 190
 191     block_mig_state.submitted--;
 192     block_mig_state.read_done++;
 193     assert(block_mig_state.submitted >= 0);
 194 }
 195
 196 static int mig_save_device_bulk(QEMUFile *f, BlkMigDevState *bmds)
 197 {
 198     int64_t total_sectors = bmds->total_sectors;
 199     int64_t cur_sector = bmds->cur_sector;
 200     BlockDriverState *bs = bmds->bs;
 201     BlkMigBlock *blk;
 202     int nr_sectors;
 203
 204     if (bmds->shared_base) {
 205         while (cur_sector < total_sectors &&
 206                !bdrv_is_allocated(bs, cur_sector, MAX_IS_ALLOCATED_SEARCH,
 207                                   &nr_sectors)) {
 208             cur_sector += nr_sectors;
 209         }
 210     }
 211
 212     if (cur_sector >= total_sectors) {
 213         bmds->cur_sector = bmds->completed_sectors = total_sectors;
 214         return 1;
 215     }
 216
 217     bmds->completed_sectors = cur_sector;
 218
 219     cur_sector &= ~((int64_t)BDRV_SECTORS_PER_DIRTY_CHUNK - 1);
 220
 221     /* we are going to transfer a full block even if it is not allocated */
 222     nr_sectors = BDRV_SECTORS_PER_DIRTY_CHUNK;
 223
 224     if (total_sectors - cur_sector < BDRV_SECTORS_PER_DIRTY_CHUNK) {
 225         nr_sectors = total_sectors - cur_sector;
 226     }
 227
 228     blk = g_malloc(sizeof(BlkMigBlock));
 229     blk->buf = g_malloc(BLOCK_SIZE);
 230     blk->bmds = bmds;
 231     blk->sector = cur_sector;
 232     blk->nr_sectors = nr_sectors;
 233
 234     blk->iov.iov_base = blk->buf;
 235     blk->iov.iov_len = nr_sectors * BDRV_SECTOR_SIZE;
 236     qemu_iovec_init_external(&blk->qiov, &blk->iov, 1);
 237
 238     if (block_mig_state.submitted == 0) {
 239         block_mig_state.prev_time_offset = qemu_get_clock_ns(rt_clock);
 240     }
 241
 242     blk->aiocb = bdrv_aio_readv(bs, cur_sector, &blk->qiov,
 243                                 nr_sectors, blk_mig_read_cb, blk);
 244     block_mig_state.submitted++;
 245
 246     bdrv_reset_dirty(bs, cur_sector, nr_sectors);
 247     bmds->cur_sector = cur_sector + nr_sectors;
 248
 249     return (bmds->cur_sector >= total_sectors);
 250 }
 251
 252 static void set_dirty_tracking(int enable)
 253 {
 254     BlkMigDevState *bmds;
 255
 256     QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
 257         bdrv_set_dirty_tracking(bmds->bs, enable);
 258     }
 259 }
 260
 261 static void init_blk_migration_it(void *opaque, BlockDriverState *bs)
 262 {
 263     BlkMigDevState *bmds;
 264     int64_t sectors;
 265
 266     if (!bdrv_is_read_only(bs)) {
 267         sectors = bdrv_getlength(bs) >> BDRV_SECTOR_BITS;
 268         if (sectors <= 0) {
 269             return;
 270         }
 271
 272         bmds = g_malloc0(sizeof(BlkMigDevState));
 273         bmds->bs = bs;
 274         bmds->bulk_completed = 0;
 275         bmds->total_sectors = sectors;
 276         bmds->completed_sectors = 0;
 277         bmds->shared_base = block_mig_state.shared_base;
 278         alloc_aio_bitmap(bmds);
 279         drive_get_ref(drive_get_by_blockdev(bs));
 280         bdrv_set_in_use(bs, 1);
 281
 282         block_mig_state.total_sector_sum += sectors;
 283
 284         if (bmds->shared_base) {
 285             DPRINTF("Start migration for %s with shared base image\n",
 286                     bs->device_name);
 287         } else {
 288             DPRINTF("Start full migration for %s\n", bs->device_name);
 289         }
 290
 291         QSIMPLEQ_INSERT_TAIL(&block_mig_state.bmds_list, bmds, entry);
 292     }
 293 }
 294
 295 static void init_blk_migration(QEMUFile *f)
 296 {
 297     block_mig_state.submitted = 0;
 298     block_mig_state.read_done = 0;
 299     block_mig_state.transferred = 0;
 300     block_mig_state.total_sector_sum = 0;
 301     block_mig_state.prev_progress = -1;
 302     block_mig_state.bulk_completed = 0;
 303
 304     bdrv_iterate(init_blk_migration_it, NULL);
 305 }
 306
 307 static int blk_mig_save_bulked_block(QEMUFile *f)
 308 {
 309     int64_t completed_sector_sum = 0;
 310     BlkMigDevState *bmds;
 311     int progress;
 312     int ret = 0;
 313
 314     QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
 315         if (bmds->bulk_completed == 0) {
 316             if (mig_save_device_bulk(f, bmds) == 1) {
 317                 /* completed bulk section for this device */
 318                 bmds->bulk_completed = 1;
 319             }
 320             completed_sector_sum += bmds->completed_sectors;
 321             ret = 1;
 322             break;
 323         } else {
 324             completed_sector_sum += bmds->completed_sectors;
 325         }
 326     }
 327
 328     if (block_mig_state.total_sector_sum != 0) {
 329         progress = completed_sector_sum * 100 /
 330                    block_mig_state.total_sector_sum;
 331     } else {
 332         progress = 100;
 333     }
 334     if (progress != block_mig_state.prev_progress) {
 335         block_mig_state.prev_progress = progress;
 336         qemu_put_be64(f, (progress << BDRV_SECTOR_BITS)
 337                          | BLK_MIG_FLAG_PROGRESS);
 338         DPRINTF("Completed %d %%\r", progress);
 339     }
 340
 341     return ret;
 342 }
 343
 344 static void blk_mig_reset_dirty_cursor(void)
 345 {
 346     BlkMigDevState *bmds;
 347
 348     QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
 349         bmds->cur_dirty = 0;
 350     }
 351 }
 352
 353 static int mig_save_device_dirty(QEMUFile *f, BlkMigDevState *bmds,
 354                                  int is_async)
 355 {
 356     BlkMigBlock *blk;
 357     int64_t total_sectors = bmds->total_sectors;
 358     int64_t sector;
 359     int nr_sectors;
 360     int ret = -EIO;
 361
 362     for (sector = bmds->cur_dirty; sector < bmds->total_sectors;) {
 363         if (bmds_aio_inflight(bmds, sector)) {
 364             bdrv_drain_all();
 365         }
 366         if (bdrv_get_dirty(bmds->bs, sector)) {
 367
 368             if (total_sectors - sector < BDRV_SECTORS_PER_DIRTY_CHUNK) {
 369                 nr_sectors = total_sectors - sector;
 370             } else {
 371                 nr_sectors = BDRV_SECTORS_PER_DIRTY_CHUNK;
 372             }
 373             blk = g_malloc(sizeof(BlkMigBlock));
 374             blk->buf = g_malloc(BLOCK_SIZE);
 375             blk->bmds = bmds;
 376             blk->sector = sector;
 377             blk->nr_sectors = nr_sectors;
 378
 379             if (is_async) {
 380                 blk->iov.iov_base = blk->buf;
 381                 blk->iov.iov_len = nr_sectors * BDRV_SECTOR_SIZE;
 382                 qemu_iovec_init_external(&blk->qiov, &blk->iov, 1);
 383
 384                 if (block_mig_state.submitted == 0) {
 385                     block_mig_state.prev_time_offset = qemu_get_clock_ns(rt_clock);
 386                 }
 387
 388                 blk->aiocb = bdrv_aio_readv(bmds->bs, sector, &blk->qiov,
 389                                             nr_sectors, blk_mig_read_cb, blk);
 390                 block_mig_state.submitted++;
 391                 bmds_set_aio_inflight(bmds, sector, nr_sectors, 1);
 392             } else {
 393                 ret = bdrv_read(bmds->bs, sector, blk->buf, nr_sectors);
 394                 if (ret < 0) {
 395                     goto error;
 396                 }
 397                 blk_send(f, blk);
 398
 399                 g_free(blk->buf);
 400                 g_free(blk);
 401             }
 402
 403             bdrv_reset_dirty(bmds->bs, sector, nr_sectors);
 404             break;
 405         }
 406         sector += BDRV_SECTORS_PER_DIRTY_CHUNK;
 407         bmds->cur_dirty = sector;
 408     }
 409
 410     return (bmds->cur_dirty >= bmds->total_sectors);
 411
 412 error:
 413     DPRINTF("Error reading sector %" PRId64 "\n", sector);
 414     g_free(blk->buf);
 415     g_free(blk);
 416     return ret;
 417 }
 418
 419 /* return value:
 420  * 0: too much data for max_downtime
 421  * 1: few enough data for max_downtime
 422 */
 423 static int blk_mig_save_dirty_block(QEMUFile *f, int is_async)
 424 {
 425     BlkMigDevState *bmds;
 426     int ret = 1;
 427
 428     QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
 429         ret = mig_save_device_dirty(f, bmds, is_async);
 430         if (ret <= 0) {
 431             break;
 432         }
 433     }
 434
 435     return ret;
 436 }
 437
 438 static int flush_blks(QEMUFile *f)
 439 {
 440     BlkMigBlock *blk;
 441     int ret = 0;
 442
 443     DPRINTF("%s Enter submitted %d read_done %d transferred %d\n",
 444             __FUNCTION__, block_mig_state.submitted, block_mig_state.read_done,
 445             block_mig_state.transferred);
 446
 447     while ((blk = QSIMPLEQ_FIRST(&block_mig_state.blk_list)) != NULL) {
 448         if (qemu_file_rate_limit(f)) {
 449             break;
 450         }
 451         if (blk->ret < 0) {
 452             ret = blk->ret;
 453             break;
 454         }
 455         blk_send(f, blk);
 456
 457         QSIMPLEQ_REMOVE_HEAD(&block_mig_state.blk_list, entry);
 458         g_free(blk->buf);
 459         g_free(blk);
 460
 461         block_mig_state.read_done--;
 462         block_mig_state.transferred++;
 463         assert(block_mig_state.read_done >= 0);
 464     }
 465
 466     DPRINTF("%s Exit submitted %d read_done %d transferred %d\n", __FUNCTION__,
 467             block_mig_state.submitted, block_mig_state.read_done,
 468             block_mig_state.transferred);
 469     return ret;
 470 }
 471
 472 static int64_t get_remaining_dirty(void)
 473 {
 474     BlkMigDevState *bmds;
 475     int64_t dirty = 0;
 476
 477     QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
 478         dirty += bdrv_get_dirty_count(bmds->bs);
 479     }
 480
 481     return dirty * BLOCK_SIZE;
 482 }
 483
 484 static void blk_mig_cleanup(void)
 485 {
 486     BlkMigDevState *bmds;
 487     BlkMigBlock *blk;
 488
 489     bdrv_drain_all();
 490
 491     set_dirty_tracking(0);
 492
 493     while ((bmds = QSIMPLEQ_FIRST(&block_mig_state.bmds_list)) != NULL) {
 494         QSIMPLEQ_REMOVE_HEAD(&block_mig_state.bmds_list, entry);
 495         bdrv_set_in_use(bmds->bs, 0);
 496         drive_put_ref(drive_get_by_blockdev(bmds->bs));
 497         g_free(bmds->aio_bitmap);
 498         g_free(bmds);
 499     }
 500
 501     while ((blk = QSIMPLEQ_FIRST(&block_mig_state.blk_list)) != NULL) {
 502         QSIMPLEQ_REMOVE_HEAD(&block_mig_state.blk_list, entry);
 503         g_free(blk->buf);
 504         g_free(blk);
 505     }
 506 }
 507
 508 static void block_migration_cancel(void *opaque)
 509 {
 510     blk_mig_cleanup();
 511 }
 512
 513 static int block_save_setup(QEMUFile *f, void *opaque)
 514 {
 515     int ret;
 516
 517     DPRINTF("Enter save live setup submitted %d transferred %d\n",
 518             block_mig_state.submitted, block_mig_state.transferred);
 519
 520     init_blk_migration(f);
 521
 522     /* start track dirty blocks */
 523     set_dirty_tracking(1);
 524
 525     ret = flush_blks(f);
 526     if (ret) {
 527         blk_mig_cleanup();
 528         return ret;
 529     }
 530
 531     blk_mig_reset_dirty_cursor();
 532
 533     qemu_put_be64(f, BLK_MIG_FLAG_EOS);
 534
 535     return 0;
 536 }
 537
 538 static int block_save_iterate(QEMUFile *f, void *opaque)
 539 {
 540     int ret;
 541
 542     DPRINTF("Enter save live iterate submitted %d transferred %d\n",
 543             block_mig_state.submitted, block_mig_state.transferred);
 544
 545     ret = flush_blks(f);
 546     if (ret) {
 547         blk_mig_cleanup();
 548         return ret;
 549     }
 550
 551     blk_mig_reset_dirty_cursor();
 552
 553     /* control the rate of transfer */
 554     while ((block_mig_state.submitted +
 555             block_mig_state.read_done) * BLOCK_SIZE <
 556            qemu_file_get_rate_limit(f)) {
 557         if (block_mig_state.bulk_completed == 0) {
 558             /* first finish the bulk phase */
 559             if (blk_mig_save_bulked_block(f) == 0) {
 560                 /* finished saving bulk on all devices */
 561                 block_mig_state.bulk_completed = 1;
 562             }
 563         } else {
 564             ret = blk_mig_save_dirty_block(f, 1);
 565             if (ret != 0) {
 566                 /* no more dirty blocks */
 567                 break;
 568             }
 569         }
 570     }
 571     if (ret) {
 572         blk_mig_cleanup();
 573         return ret;
 574     }
 575
 576     ret = flush_blks(f);
 577     if (ret) {
 578         blk_mig_cleanup();
 579         return ret;
 580     }
 581
 582     qemu_put_be64(f, BLK_MIG_FLAG_EOS);
 583
 584     return 0;
 585 }
 586
 587 static int block_save_complete(QEMUFile *f, void *opaque)
 588 {
 589     int ret;
 590
 591     DPRINTF("Enter save live complete submitted %d transferred %d\n",
 592             block_mig_state.submitted, block_mig_state.transferred);
 593
 594     ret = flush_blks(f);
 595     if (ret) {
 596         blk_mig_cleanup();
 597         return ret;
 598     }
 599
 600     blk_mig_reset_dirty_cursor();
 601
 602     /* we know for sure that save bulk is completed and
 603        all async read completed */
 604     assert(block_mig_state.submitted == 0);
 605
 606     do {
 607         ret = blk_mig_save_dirty_block(f, 0);
 608     } while (ret == 0);
 609
 610     blk_mig_cleanup();
 611     if (ret) {
 612         return ret;
 613     }
 614     /* report completion */
 615     qemu_put_be64(f, (100 << BDRV_SECTOR_BITS) | BLK_MIG_FLAG_PROGRESS);
 616
 617     DPRINTF("Block migration completed\n");
 618
 619     qemu_put_be64(f, BLK_MIG_FLAG_EOS);
 620
 621     return 0;
 622 }
 623
 624 static uint64_t block_save_pending(QEMUFile *f, void *opaque, uint64_t max_size)
 625 {
 626
 627     DPRINTF("Enter save live pending  %ld\n", get_remaining_dirty());
 628
 629     return get_remaining_dirty();
 630 }
 631
 632 static int block_load(QEMUFile *f, void *opaque, int version_id)
 633 {
 634     static int banner_printed;
 635     int len, flags;
 636     char device_name[256];
 637     int64_t addr;
 638     BlockDriverState *bs, *bs_prev = NULL;
 639     uint8_t *buf;
 640     int64_t total_sectors = 0;
 641     int nr_sectors;
 642     int ret;
 643
 644     do {
 645         addr = qemu_get_be64(f);
 646
 647         flags = addr & ~BDRV_SECTOR_MASK;
 648         addr >>= BDRV_SECTOR_BITS;
 649
 650         if (flags & BLK_MIG_FLAG_DEVICE_BLOCK) {
 651             /* get device name */
 652             len = qemu_get_byte(f);
 653             qemu_get_buffer(f, (uint8_t *)device_name, len);
 654             device_name[len] = '\0';
 655
 656             bs = bdrv_find(device_name);
 657             if (!bs) {
 658                 fprintf(stderr, "Error unknown block device %s\n",
 659                         device_name);
 660                 return -EINVAL;
 661             }
 662
 663             if (bs != bs_prev) {
 664                 bs_prev = bs;
 665                 total_sectors = bdrv_getlength(bs) >> BDRV_SECTOR_BITS;
 666                 if (total_sectors <= 0) {
 667                     error_report("Error getting length of block device %s",
 668                                  device_name);
 669                     return -EINVAL;
 670                 }
 671             }
 672
 673             if (total_sectors - addr < BDRV_SECTORS_PER_DIRTY_CHUNK) {
 674                 nr_sectors = total_sectors - addr;
 675             } else {
 676                 nr_sectors = BDRV_SECTORS_PER_DIRTY_CHUNK;
 677             }
 678
 679             buf = g_malloc(BLOCK_SIZE);
 680
 681             qemu_get_buffer(f, buf, BLOCK_SIZE);
 682             ret = bdrv_write(bs, addr, buf, nr_sectors);
 683
 684             g_free(buf);
 685             if (ret < 0) {
 686                 return ret;
 687             }
 688         } else if (flags & BLK_MIG_FLAG_PROGRESS) {
 689             if (!banner_printed) {
 690                 printf("Receiving block device images\n");
 691                 banner_printed = 1;
 692             }
 693             printf("Completed %d %%%c", (int)addr,
 694                    (addr == 100) ? '\n' : '\r');
 695             fflush(stdout);
 696         } else if (!(flags & BLK_MIG_FLAG_EOS)) {
 697             fprintf(stderr, "Unknown flags\n");
 698             return -EINVAL;
 699         }
 700         ret = qemu_file_get_error(f);
 701         if (ret != 0) {
 702             return ret;
 703         }
 704     } while (!(flags & BLK_MIG_FLAG_EOS));
 705
 706     return 0;
 707 }
 708
 709 static void block_set_params(const MigrationParams *params, void *opaque)
 710 {
 711     block_mig_state.blk_enable = params->blk;
 712     block_mig_state.shared_base = params->shared;
 713
 714     /* shared base means that blk_enable = 1 */
 715     block_mig_state.blk_enable |= params->shared;
 716 }
 717
 718 static bool block_is_active(void *opaque)
 719 {
 720     return block_mig_state.blk_enable == 1;
 721 }
 722
 723 SaveVMHandlers savevm_block_handlers = {
 724     .set_params = block_set_params,
 725     .save_live_setup = block_save_setup,
 726     .save_live_iterate = block_save_iterate,
 727     .save_live_complete = block_save_complete,
 728     .save_live_pending = block_save_pending,
 729     .load_state = block_load,
 730     .cancel = block_migration_cancel,
 731     .is_active = block_is_active,
 732 };
 733
 734 void blk_mig_init(void)
 735 {
 736     QSIMPLEQ_INIT(&block_mig_state.bmds_list);
 737     QSIMPLEQ_INIT(&block_mig_state.blk_list);
 738
 739     register_savevm_live(NULL, "block", 0, 1, &savevm_block_handlers,
 740                          &block_mig_state);
 741 }