block-migration.c

   1 /*
   2  * QEMU live block migration
   3  *
   4  * Copyright IBM, Corp. 2009
   5  *
   6  * Authors:
   7  *  Liran Schour   <lirans@il.ibm.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2.  See
  10  * the COPYING file in the top-level directory.
  11  *
  12  * Contributions after 2012-01-13 are licensed under the terms of the
  13  * GNU GPL, version 2 or (at your option) any later version.
  14  */
  15
  16 #include "qemu-common.h"
  17 #include "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                       (1 << 20)
  27 #define BDRV_SECTORS_PER_DIRTY_CHUNK     (BLOCK_SIZE >> BDRV_SECTOR_BITS)
  28
  29 #define BLK_MIG_FLAG_DEVICE_BLOCK       0x01
  30 #define BLK_MIG_FLAG_EOS                0x02
  31 #define BLK_MIG_FLAG_PROGRESS           0x04
  32
  33 #define MAX_IS_ALLOCATED_SEARCH 65536
  34
  35 //#define DEBUG_BLK_MIGRATION
  36
  37 #ifdef DEBUG_BLK_MIGRATION
  38 #define DPRINTF(fmt, ...) \
  39     do { printf("blk_migration: " fmt, ## __VA_ARGS__); } while (0)
  40 #else
  41 #define DPRINTF(fmt, ...) \
  42     do { } while (0)
  43 #endif
  44
  45 typedef struct BlkMigDevState {
  46     /* Written during setup phase.  Can be read without a lock.  */
  47     BlockDriverState *bs;
  48     int shared_base;
  49     int64_t total_sectors;
  50     QSIMPLEQ_ENTRY(BlkMigDevState) entry;
  51
  52     /* Only used by migration thread.  Does not need a lock.  */
  53     int bulk_completed;
  54     int64_t cur_sector;
  55     int64_t cur_dirty;
  56
  57     /* Protected by block migration lock.  */
  58     unsigned long *aio_bitmap;
  59     int64_t completed_sectors;
  60 } BlkMigDevState;
  61
  62 typedef struct BlkMigBlock {
  63     /* Only used by migration thread.  */
  64     uint8_t *buf;
  65     BlkMigDevState *bmds;
  66     int64_t sector;
  67     int nr_sectors;
  68     struct iovec iov;
  69     QEMUIOVector qiov;
  70     BlockDriverAIOCB *aiocb;
  71
  72     /* Protected by block migration lock.  */
  73     int ret;
  74     QSIMPLEQ_ENTRY(BlkMigBlock) entry;
  75 } BlkMigBlock;
  76
  77 typedef struct BlkMigState {
  78     /* Written during setup phase.  Can be read without a lock.  */
  79     int blk_enable;
  80     int shared_base;
  81     QSIMPLEQ_HEAD(bmds_list, BlkMigDevState) bmds_list;
  82     int64_t total_sector_sum;
  83
  84     /* Protected by lock.  */
  85     QSIMPLEQ_HEAD(blk_list, BlkMigBlock) blk_list;
  86     int submitted;
  87     int read_done;
  88
  89     /* Only used by migration thread.  Does not need a lock.  */
  90     int transferred;
  91     int prev_progress;
  92     int bulk_completed;
  93
  94     /* Lock must be taken _inside_ the iothread lock.  */
  95     QemuMutex lock;
  96 } BlkMigState;
  97
  98 static BlkMigState block_mig_state;
  99
 100 static void blk_mig_lock(void)
 101 {
 102     qemu_mutex_lock(&block_mig_state.lock);
 103 }
 104
 105 static void blk_mig_unlock(void)
 106 {
 107     qemu_mutex_unlock(&block_mig_state.lock);
 108 }
 109
 110 /* Must run outside of the iothread lock during the bulk phase,
 111  * or the VM will stall.
 112  */
 113
 114 static void blk_send(QEMUFile *f, BlkMigBlock * blk)
 115 {
 116     int len;
 117
 118     /* sector number and flags */
 119     qemu_put_be64(f, (blk->sector << BDRV_SECTOR_BITS)
 120                      | BLK_MIG_FLAG_DEVICE_BLOCK);
 121
 122     /* device name */
 123     len = strlen(blk->bmds->bs->device_name);
 124     qemu_put_byte(f, len);
 125     qemu_put_buffer(f, (uint8_t *)blk->bmds->bs->device_name, len);
 126
 127     qemu_put_buffer(f, blk->buf, BLOCK_SIZE);
 128 }
 129
 130 int blk_mig_active(void)
 131 {
 132     return !QSIMPLEQ_EMPTY(&block_mig_state.bmds_list);
 133 }
 134
 135 uint64_t blk_mig_bytes_transferred(void)
 136 {
 137     BlkMigDevState *bmds;
 138     uint64_t sum = 0;
 139
 140     blk_mig_lock();
 141     QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
 142         sum += bmds->completed_sectors;
 143     }
 144     blk_mig_unlock();
 145     return sum << BDRV_SECTOR_BITS;
 146 }
 147
 148 uint64_t blk_mig_bytes_remaining(void)
 149 {
 150     return blk_mig_bytes_total() - blk_mig_bytes_transferred();
 151 }
 152
 153 uint64_t blk_mig_bytes_total(void)
 154 {
 155     BlkMigDevState *bmds;
 156     uint64_t sum = 0;
 157
 158     QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
 159         sum += bmds->total_sectors;
 160     }
 161     return sum << BDRV_SECTOR_BITS;
 162 }
 163
 164
 165 /* Called with migration lock held.  */
 166
 167 static int bmds_aio_inflight(BlkMigDevState *bmds, int64_t sector)
 168 {
 169     int64_t chunk = sector / (int64_t)BDRV_SECTORS_PER_DIRTY_CHUNK;
 170
 171     if ((sector << BDRV_SECTOR_BITS) < bdrv_getlength(bmds->bs)) {
 172         return !!(bmds->aio_bitmap[chunk / (sizeof(unsigned long) * 8)] &
 173             (1UL << (chunk % (sizeof(unsigned long) * 8))));
 174     } else {
 175         return 0;
 176     }
 177 }
 178
 179 /* Called with migration lock held.  */
 180
 181 static void bmds_set_aio_inflight(BlkMigDevState *bmds, int64_t sector_num,
 182                              int nb_sectors, int set)
 183 {
 184     int64_t start, end;
 185     unsigned long val, idx, bit;
 186
 187     start = sector_num / BDRV_SECTORS_PER_DIRTY_CHUNK;
 188     end = (sector_num + nb_sectors - 1) / BDRV_SECTORS_PER_DIRTY_CHUNK;
 189
 190     for (; start <= end; start++) {
 191         idx = start / (sizeof(unsigned long) * 8);
 192         bit = start % (sizeof(unsigned long) * 8);
 193         val = bmds->aio_bitmap[idx];
 194         if (set) {
 195             val |= 1UL << bit;
 196         } else {
 197             val &= ~(1UL << bit);
 198         }
 199         bmds->aio_bitmap[idx] = val;
 200     }
 201 }
 202
 203 static void alloc_aio_bitmap(BlkMigDevState *bmds)
 204 {
 205     BlockDriverState *bs = bmds->bs;
 206     int64_t bitmap_size;
 207
 208     bitmap_size = (bdrv_getlength(bs) >> BDRV_SECTOR_BITS) +
 209             BDRV_SECTORS_PER_DIRTY_CHUNK * 8 - 1;
 210     bitmap_size /= BDRV_SECTORS_PER_DIRTY_CHUNK * 8;
 211
 212     bmds->aio_bitmap = g_malloc0(bitmap_size);
 213 }
 214
 215 /* Never hold migration lock when yielding to the main loop!  */
 216
 217 static void blk_mig_read_cb(void *opaque, int ret)
 218 {
 219     BlkMigBlock *blk = opaque;
 220
 221     blk_mig_lock();
 222     blk->ret = ret;
 223
 224     QSIMPLEQ_INSERT_TAIL(&block_mig_state.blk_list, blk, entry);
 225     bmds_set_aio_inflight(blk->bmds, blk->sector, blk->nr_sectors, 0);
 226
 227     block_mig_state.submitted--;
 228     block_mig_state.read_done++;
 229     assert(block_mig_state.submitted >= 0);
 230     blk_mig_unlock();
 231 }
 232
 233 /* Called with no lock taken.  */
 234
 235 static int mig_save_device_bulk(QEMUFile *f, BlkMigDevState *bmds)
 236 {
 237     int64_t total_sectors = bmds->total_sectors;
 238     int64_t cur_sector = bmds->cur_sector;
 239     BlockDriverState *bs = bmds->bs;
 240     BlkMigBlock *blk;
 241     int nr_sectors;
 242
 243     if (bmds->shared_base) {
 244         qemu_mutex_lock_iothread();
 245         while (cur_sector < total_sectors &&
 246                !bdrv_is_allocated(bs, cur_sector, MAX_IS_ALLOCATED_SEARCH,
 247                                   &nr_sectors)) {
 248             cur_sector += nr_sectors;
 249         }
 250         qemu_mutex_unlock_iothread();
 251     }
 252
 253     if (cur_sector >= total_sectors) {
 254         bmds->cur_sector = bmds->completed_sectors = total_sectors;
 255         return 1;
 256     }
 257
 258     bmds->completed_sectors = cur_sector;
 259
 260     cur_sector &= ~((int64_t)BDRV_SECTORS_PER_DIRTY_CHUNK - 1);
 261
 262     /* we are going to transfer a full block even if it is not allocated */
 263     nr_sectors = BDRV_SECTORS_PER_DIRTY_CHUNK;
 264
 265     if (total_sectors - cur_sector < BDRV_SECTORS_PER_DIRTY_CHUNK) {
 266         nr_sectors = total_sectors - cur_sector;
 267     }
 268
 269     blk = g_malloc(sizeof(BlkMigBlock));
 270     blk->buf = g_malloc(BLOCK_SIZE);
 271     blk->bmds = bmds;
 272     blk->sector = cur_sector;
 273     blk->nr_sectors = nr_sectors;
 274
 275     blk->iov.iov_base = blk->buf;
 276     blk->iov.iov_len = nr_sectors * BDRV_SECTOR_SIZE;
 277     qemu_iovec_init_external(&blk->qiov, &blk->iov, 1);
 278
 279     blk_mig_lock();
 280     block_mig_state.submitted++;
 281     blk_mig_unlock();
 282
 283     qemu_mutex_lock_iothread();
 284     blk->aiocb = bdrv_aio_readv(bs, cur_sector, &blk->qiov,
 285                                 nr_sectors, blk_mig_read_cb, blk);
 286
 287     bdrv_reset_dirty(bs, cur_sector, nr_sectors);
 288     qemu_mutex_unlock_iothread();
 289
 290     bmds->cur_sector = cur_sector + nr_sectors;
 291     return (bmds->cur_sector >= total_sectors);
 292 }
 293
 294 /* Called with iothread lock taken.  */
 295
 296 static void set_dirty_tracking(int enable)
 297 {
 298     BlkMigDevState *bmds;
 299
 300     QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
 301         bdrv_set_dirty_tracking(bmds->bs, enable ? BLOCK_SIZE : 0);
 302     }
 303 }
 304
 305 static void init_blk_migration_it(void *opaque, BlockDriverState *bs)
 306 {
 307     BlkMigDevState *bmds;
 308     int64_t sectors;
 309
 310     if (!bdrv_is_read_only(bs)) {
 311         sectors = bdrv_getlength(bs) >> BDRV_SECTOR_BITS;
 312         if (sectors <= 0) {
 313             return;
 314         }
 315
 316         bmds = g_malloc0(sizeof(BlkMigDevState));
 317         bmds->bs = bs;
 318         bmds->bulk_completed = 0;
 319         bmds->total_sectors = sectors;
 320         bmds->completed_sectors = 0;
 321         bmds->shared_base = block_mig_state.shared_base;
 322         alloc_aio_bitmap(bmds);
 323         drive_get_ref(drive_get_by_blockdev(bs));
 324         bdrv_set_in_use(bs, 1);
 325
 326         block_mig_state.total_sector_sum += sectors;
 327
 328         if (bmds->shared_base) {
 329             DPRINTF("Start migration for %s with shared base image\n",
 330                     bs->device_name);
 331         } else {
 332             DPRINTF("Start full migration for %s\n", bs->device_name);
 333         }
 334
 335         QSIMPLEQ_INSERT_TAIL(&block_mig_state.bmds_list, bmds, entry);
 336     }
 337 }
 338
 339 static void init_blk_migration(QEMUFile *f)
 340 {
 341     block_mig_state.submitted = 0;
 342     block_mig_state.read_done = 0;
 343     block_mig_state.transferred = 0;
 344     block_mig_state.total_sector_sum = 0;
 345     block_mig_state.prev_progress = -1;
 346     block_mig_state.bulk_completed = 0;
 347
 348     bdrv_iterate(init_blk_migration_it, NULL);
 349 }
 350
 351 /* Called with no lock taken.  */
 352
 353 static int blk_mig_save_bulked_block(QEMUFile *f)
 354 {
 355     int64_t completed_sector_sum = 0;
 356     BlkMigDevState *bmds;
 357     int progress;
 358     int ret = 0;
 359
 360     QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
 361         if (bmds->bulk_completed == 0) {
 362             if (mig_save_device_bulk(f, bmds) == 1) {
 363                 /* completed bulk section for this device */
 364                 bmds->bulk_completed = 1;
 365             }
 366             completed_sector_sum += bmds->completed_sectors;
 367             ret = 1;
 368             break;
 369         } else {
 370             completed_sector_sum += bmds->completed_sectors;
 371         }
 372     }
 373
 374     if (block_mig_state.total_sector_sum != 0) {
 375         progress = completed_sector_sum * 100 /
 376                    block_mig_state.total_sector_sum;
 377     } else {
 378         progress = 100;
 379     }
 380     if (progress != block_mig_state.prev_progress) {
 381         block_mig_state.prev_progress = progress;
 382         qemu_put_be64(f, (progress << BDRV_SECTOR_BITS)
 383                          | BLK_MIG_FLAG_PROGRESS);
 384         DPRINTF("Completed %d %%\r", progress);
 385     }
 386
 387     return ret;
 388 }
 389
 390 static void blk_mig_reset_dirty_cursor(void)
 391 {
 392     BlkMigDevState *bmds;
 393
 394     QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
 395         bmds->cur_dirty = 0;
 396     }
 397 }
 398
 399 /* Called with iothread lock taken.  */
 400
 401 static int mig_save_device_dirty(QEMUFile *f, BlkMigDevState *bmds,
 402                                  int is_async)
 403 {
 404     BlkMigBlock *blk;
 405     int64_t total_sectors = bmds->total_sectors;
 406     int64_t sector;
 407     int nr_sectors;
 408     int ret = -EIO;
 409
 410     for (sector = bmds->cur_dirty; sector < bmds->total_sectors;) {
 411         blk_mig_lock();
 412         if (bmds_aio_inflight(bmds, sector)) {
 413             blk_mig_unlock();
 414             bdrv_drain_all();
 415         } else {
 416             blk_mig_unlock();
 417         }
 418         if (bdrv_get_dirty(bmds->bs, sector)) {
 419
 420             if (total_sectors - sector < BDRV_SECTORS_PER_DIRTY_CHUNK) {
 421                 nr_sectors = total_sectors - sector;
 422             } else {
 423                 nr_sectors = BDRV_SECTORS_PER_DIRTY_CHUNK;
 424             }
 425             blk = g_malloc(sizeof(BlkMigBlock));
 426             blk->buf = g_malloc(BLOCK_SIZE);
 427             blk->bmds = bmds;
 428             blk->sector = sector;
 429             blk->nr_sectors = nr_sectors;
 430
 431             if (is_async) {
 432                 blk->iov.iov_base = blk->buf;
 433                 blk->iov.iov_len = nr_sectors * BDRV_SECTOR_SIZE;
 434                 qemu_iovec_init_external(&blk->qiov, &blk->iov, 1);
 435
 436                 blk->aiocb = bdrv_aio_readv(bmds->bs, sector, &blk->qiov,
 437                                             nr_sectors, blk_mig_read_cb, blk);
 438
 439                 blk_mig_lock();
 440                 block_mig_state.submitted++;
 441                 bmds_set_aio_inflight(bmds, sector, nr_sectors, 1);
 442                 blk_mig_unlock();
 443             } else {
 444                 ret = bdrv_read(bmds->bs, sector, blk->buf, nr_sectors);
 445                 if (ret < 0) {
 446                     goto error;
 447                 }
 448                 blk_send(f, blk);
 449
 450                 g_free(blk->buf);
 451                 g_free(blk);
 452             }
 453
 454             bdrv_reset_dirty(bmds->bs, sector, nr_sectors);
 455             break;
 456         }
 457         sector += BDRV_SECTORS_PER_DIRTY_CHUNK;
 458         bmds->cur_dirty = sector;
 459     }
 460
 461     return (bmds->cur_dirty >= bmds->total_sectors);
 462
 463 error:
 464     DPRINTF("Error reading sector %" PRId64 "\n", sector);
 465     g_free(blk->buf);
 466     g_free(blk);
 467     return ret;
 468 }
 469
 470 /* Called with iothread lock taken.
 471  *
 472  * return value:
 473  * 0: too much data for max_downtime
 474  * 1: few enough data for max_downtime
 475 */
 476 static int blk_mig_save_dirty_block(QEMUFile *f, int is_async)
 477 {
 478     BlkMigDevState *bmds;
 479     int ret = 1;
 480
 481     QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
 482         ret = mig_save_device_dirty(f, bmds, is_async);
 483         if (ret <= 0) {
 484             break;
 485         }
 486     }
 487
 488     return ret;
 489 }
 490
 491 /* Called with no locks taken.  */
 492
 493 static int flush_blks(QEMUFile *f)
 494 {
 495     BlkMigBlock *blk;
 496     int ret = 0;
 497
 498     DPRINTF("%s Enter submitted %d read_done %d transferred %d\n",
 499             __FUNCTION__, block_mig_state.submitted, block_mig_state.read_done,
 500             block_mig_state.transferred);
 501
 502     blk_mig_lock();
 503     while ((blk = QSIMPLEQ_FIRST(&block_mig_state.blk_list)) != NULL) {
 504         if (qemu_file_rate_limit(f)) {
 505             break;
 506         }
 507         if (blk->ret < 0) {
 508             ret = blk->ret;
 509             break;
 510         }
 511
 512         QSIMPLEQ_REMOVE_HEAD(&block_mig_state.blk_list, entry);
 513         blk_mig_unlock();
 514         blk_send(f, blk);
 515         blk_mig_lock();
 516
 517         g_free(blk->buf);
 518         g_free(blk);
 519
 520         block_mig_state.read_done--;
 521         block_mig_state.transferred++;
 522         assert(block_mig_state.read_done >= 0);
 523     }
 524     blk_mig_unlock();
 525
 526     DPRINTF("%s Exit submitted %d read_done %d transferred %d\n", __FUNCTION__,
 527             block_mig_state.submitted, block_mig_state.read_done,
 528             block_mig_state.transferred);
 529     return ret;
 530 }
 531
 532 /* Called with iothread lock taken.  */
 533
 534 static int64_t get_remaining_dirty(void)
 535 {
 536     BlkMigDevState *bmds;
 537     int64_t dirty = 0;
 538
 539     QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
 540         dirty += bdrv_get_dirty_count(bmds->bs);
 541     }
 542
 543     return dirty << BDRV_SECTOR_BITS;
 544 }
 545
 546 /* Called with iothread lock taken.  */
 547
 548 static void blk_mig_cleanup(void)
 549 {
 550     BlkMigDevState *bmds;
 551     BlkMigBlock *blk;
 552
 553     bdrv_drain_all();
 554
 555     set_dirty_tracking(0);
 556
 557     blk_mig_lock();
 558     while ((bmds = QSIMPLEQ_FIRST(&block_mig_state.bmds_list)) != NULL) {
 559         QSIMPLEQ_REMOVE_HEAD(&block_mig_state.bmds_list, entry);
 560         bdrv_set_in_use(bmds->bs, 0);
 561         drive_put_ref(drive_get_by_blockdev(bmds->bs));
 562         g_free(bmds->aio_bitmap);
 563         g_free(bmds);
 564     }
 565
 566     while ((blk = QSIMPLEQ_FIRST(&block_mig_state.blk_list)) != NULL) {
 567         QSIMPLEQ_REMOVE_HEAD(&block_mig_state.blk_list, entry);
 568         g_free(blk->buf);
 569         g_free(blk);
 570     }
 571     blk_mig_unlock();
 572 }
 573
 574 static void block_migration_cancel(void *opaque)
 575 {
 576     blk_mig_cleanup();
 577 }
 578
 579 static int block_save_setup(QEMUFile *f, void *opaque)
 580 {
 581     int ret;
 582
 583     DPRINTF("Enter save live setup submitted %d transferred %d\n",
 584             block_mig_state.submitted, block_mig_state.transferred);
 585
 586     qemu_mutex_lock_iothread();
 587     init_blk_migration(f);
 588
 589     /* start track dirty blocks */
 590     set_dirty_tracking(1);
 591     qemu_mutex_unlock_iothread();
 592
 593     ret = flush_blks(f);
 594     blk_mig_reset_dirty_cursor();
 595     qemu_put_be64(f, BLK_MIG_FLAG_EOS);
 596
 597     return ret;
 598 }
 599
 600 static int block_save_iterate(QEMUFile *f, void *opaque)
 601 {
 602     int ret;
 603     int64_t last_ftell = qemu_ftell(f);
 604
 605     DPRINTF("Enter save live iterate submitted %d transferred %d\n",
 606             block_mig_state.submitted, block_mig_state.transferred);
 607
 608     ret = flush_blks(f);
 609     if (ret) {
 610         return ret;
 611     }
 612
 613     blk_mig_reset_dirty_cursor();
 614
 615     /* control the rate of transfer */
 616     blk_mig_lock();
 617     while ((block_mig_state.submitted +
 618             block_mig_state.read_done) * BLOCK_SIZE <
 619            qemu_file_get_rate_limit(f)) {
 620         blk_mig_unlock();
 621         if (block_mig_state.bulk_completed == 0) {
 622             /* first finish the bulk phase */
 623             if (blk_mig_save_bulked_block(f) == 0) {
 624                 /* finished saving bulk on all devices */
 625                 block_mig_state.bulk_completed = 1;
 626             }
 627             ret = 0;
 628         } else {
 629             /* Always called with iothread lock taken for
 630              * simplicity, block_save_complete also calls it.
 631              */
 632             qemu_mutex_lock_iothread();
 633             ret = blk_mig_save_dirty_block(f, 1);
 634             qemu_mutex_unlock_iothread();
 635         }
 636         if (ret < 0) {
 637             return ret;
 638         }
 639         blk_mig_lock();
 640         if (ret != 0) {
 641             /* no more dirty blocks */
 642             break;
 643         }
 644     }
 645     blk_mig_unlock();
 646
 647     ret = flush_blks(f);
 648     if (ret) {
 649         return ret;
 650     }
 651
 652     qemu_put_be64(f, BLK_MIG_FLAG_EOS);
 653     return qemu_ftell(f) - last_ftell;
 654 }
 655
 656 /* Called with iothread lock taken.  */
 657
 658 static int block_save_complete(QEMUFile *f, void *opaque)
 659 {
 660     int ret;
 661
 662     DPRINTF("Enter save live complete submitted %d transferred %d\n",
 663             block_mig_state.submitted, block_mig_state.transferred);
 664
 665     ret = flush_blks(f);
 666     if (ret) {
 667         return ret;
 668     }
 669
 670     blk_mig_reset_dirty_cursor();
 671
 672     /* we know for sure that save bulk is completed and
 673        all async read completed */
 674     blk_mig_lock();
 675     assert(block_mig_state.submitted == 0);
 676     blk_mig_unlock();
 677
 678     do {
 679         ret = blk_mig_save_dirty_block(f, 0);
 680         if (ret < 0) {
 681             return ret;
 682         }
 683     } while (ret == 0);
 684
 685     /* report completion */
 686     qemu_put_be64(f, (100 << BDRV_SECTOR_BITS) | BLK_MIG_FLAG_PROGRESS);
 687
 688     DPRINTF("Block migration completed\n");
 689
 690     qemu_put_be64(f, BLK_MIG_FLAG_EOS);
 691
 692     blk_mig_cleanup();
 693     return 0;
 694 }
 695
 696 static uint64_t block_save_pending(QEMUFile *f, void *opaque, uint64_t max_size)
 697 {
 698     /* Estimate pending number of bytes to send */
 699     uint64_t pending;
 700
 701     qemu_mutex_lock_iothread();
 702     blk_mig_lock();
 703     pending = get_remaining_dirty() +
 704                        block_mig_state.submitted * BLOCK_SIZE +
 705                        block_mig_state.read_done * BLOCK_SIZE;
 706
 707     /* Report at least one block pending during bulk phase */
 708     if (pending == 0 && !block_mig_state.bulk_completed) {
 709         pending = BLOCK_SIZE;
 710     }
 711     blk_mig_unlock();
 712     qemu_mutex_unlock_iothread();
 713
 714     DPRINTF("Enter save live pending  %" PRIu64 "\n", pending);
 715     return pending;
 716 }
 717
 718 static int block_load(QEMUFile *f, void *opaque, int version_id)
 719 {
 720     static int banner_printed;
 721     int len, flags;
 722     char device_name[256];
 723     int64_t addr;
 724     BlockDriverState *bs, *bs_prev = NULL;
 725     uint8_t *buf;
 726     int64_t total_sectors = 0;
 727     int nr_sectors;
 728     int ret;
 729
 730     do {
 731         addr = qemu_get_be64(f);
 732
 733         flags = addr & ~BDRV_SECTOR_MASK;
 734         addr >>= BDRV_SECTOR_BITS;
 735
 736         if (flags & BLK_MIG_FLAG_DEVICE_BLOCK) {
 737             /* get device name */
 738             len = qemu_get_byte(f);
 739             qemu_get_buffer(f, (uint8_t *)device_name, len);
 740             device_name[len] = '\0';
 741
 742             bs = bdrv_find(device_name);
 743             if (!bs) {
 744                 fprintf(stderr, "Error unknown block device %s\n",
 745                         device_name);
 746                 return -EINVAL;
 747             }
 748
 749             if (bs != bs_prev) {
 750                 bs_prev = bs;
 751                 total_sectors = bdrv_getlength(bs) >> BDRV_SECTOR_BITS;
 752                 if (total_sectors <= 0) {
 753                     error_report("Error getting length of block device %s",
 754                                  device_name);
 755                     return -EINVAL;
 756                 }
 757             }
 758
 759             if (total_sectors - addr < BDRV_SECTORS_PER_DIRTY_CHUNK) {
 760                 nr_sectors = total_sectors - addr;
 761             } else {
 762                 nr_sectors = BDRV_SECTORS_PER_DIRTY_CHUNK;
 763             }
 764
 765             buf = g_malloc(BLOCK_SIZE);
 766
 767             qemu_get_buffer(f, buf, BLOCK_SIZE);
 768             ret = bdrv_write(bs, addr, buf, nr_sectors);
 769
 770             g_free(buf);
 771             if (ret < 0) {
 772                 return ret;
 773             }
 774         } else if (flags & BLK_MIG_FLAG_PROGRESS) {
 775             if (!banner_printed) {
 776                 printf("Receiving block device images\n");
 777                 banner_printed = 1;
 778             }
 779             printf("Completed %d %%%c", (int)addr,
 780                    (addr == 100) ? '\n' : '\r');
 781             fflush(stdout);
 782         } else if (!(flags & BLK_MIG_FLAG_EOS)) {
 783             fprintf(stderr, "Unknown block migration flags: %#x\n", flags);
 784             return -EINVAL;
 785         }
 786         ret = qemu_file_get_error(f);
 787         if (ret != 0) {
 788             return ret;
 789         }
 790     } while (!(flags & BLK_MIG_FLAG_EOS));
 791
 792     return 0;
 793 }
 794
 795 static void block_set_params(const MigrationParams *params, void *opaque)
 796 {
 797     block_mig_state.blk_enable = params->blk;
 798     block_mig_state.shared_base = params->shared;
 799
 800     /* shared base means that blk_enable = 1 */
 801     block_mig_state.blk_enable |= params->shared;
 802 }
 803
 804 static bool block_is_active(void *opaque)
 805 {
 806     return block_mig_state.blk_enable == 1;
 807 }
 808
 809 SaveVMHandlers savevm_block_handlers = {
 810     .set_params = block_set_params,
 811     .save_live_setup = block_save_setup,
 812     .save_live_iterate = block_save_iterate,
 813     .save_live_complete = block_save_complete,
 814     .save_live_pending = block_save_pending,
 815     .load_state = block_load,
 816     .cancel = block_migration_cancel,
 817     .is_active = block_is_active,
 818 };
 819
 820 void blk_mig_init(void)
 821 {
 822     QSIMPLEQ_INIT(&block_mig_state.bmds_list);
 823     QSIMPLEQ_INIT(&block_mig_state.blk_list);
 824     qemu_mutex_init(&block_mig_state.lock);
 825
 826     register_savevm_live(NULL, "block", 0, 1, &savevm_block_handlers,
 827                          &block_mig_state);
 828 }