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 #define BLK_MIG_FLAG_ZERO_BLOCK         0x08
  33
  34 #define MAX_IS_ALLOCATED_SEARCH 65536
  35
  36 //#define DEBUG_BLK_MIGRATION
  37
  38 #ifdef DEBUG_BLK_MIGRATION
  39 #define DPRINTF(fmt, ...) \
  40     do { printf("blk_migration: " fmt, ## __VA_ARGS__); } while (0)
  41 #else
  42 #define DPRINTF(fmt, ...) \
  43     do { } while (0)
  44 #endif
  45
  46 typedef struct BlkMigDevState {
  47     /* Written during setup phase.  Can be read without a lock.  */
  48     BlockDriverState *bs;
  49     int shared_base;
  50     int64_t total_sectors;
  51     QSIMPLEQ_ENTRY(BlkMigDevState) entry;
  52
  53     /* Only used by migration thread.  Does not need a lock.  */
  54     int bulk_completed;
  55     int64_t cur_sector;
  56     int64_t cur_dirty;
  57
  58     /* Protected by block migration lock.  */
  59     unsigned long *aio_bitmap;
  60     int64_t completed_sectors;
  61 } BlkMigDevState;
  62
  63 typedef struct BlkMigBlock {
  64     /* Only used by migration thread.  */
  65     uint8_t *buf;
  66     BlkMigDevState *bmds;
  67     int64_t sector;
  68     int nr_sectors;
  69     struct iovec iov;
  70     QEMUIOVector qiov;
  71     BlockDriverAIOCB *aiocb;
  72
  73     /* Protected by block migration lock.  */
  74     int ret;
  75     QSIMPLEQ_ENTRY(BlkMigBlock) entry;
  76 } BlkMigBlock;
  77
  78 typedef struct BlkMigState {
  79     /* Written during setup phase.  Can be read without a lock.  */
  80     int blk_enable;
  81     int shared_base;
  82     QSIMPLEQ_HEAD(bmds_list, BlkMigDevState) bmds_list;
  83     int64_t total_sector_sum;
  84     bool zero_blocks;
  85
  86     /* Protected by lock.  */
  87     QSIMPLEQ_HEAD(blk_list, BlkMigBlock) blk_list;
  88     int submitted;
  89     int read_done;
  90
  91     /* Only used by migration thread.  Does not need a lock.  */
  92     int transferred;
  93     int prev_progress;
  94     int bulk_completed;
  95
  96     /* Lock must be taken _inside_ the iothread lock.  */
  97     QemuMutex lock;
  98 } BlkMigState;
  99
 100 static BlkMigState block_mig_state;
 101
 102 static void blk_mig_lock(void)
 103 {
 104     qemu_mutex_lock(&block_mig_state.lock);
 105 }
 106
 107 static void blk_mig_unlock(void)
 108 {
 109     qemu_mutex_unlock(&block_mig_state.lock);
 110 }
 111
 112 /* Must run outside of the iothread lock during the bulk phase,
 113  * or the VM will stall.
 114  */
 115
 116 static void blk_send(QEMUFile *f, BlkMigBlock * blk)
 117 {
 118     int len;
 119     uint64_t flags = BLK_MIG_FLAG_DEVICE_BLOCK;
 120
 121     if (block_mig_state.zero_blocks &&
 122         buffer_is_zero(blk->buf, BLOCK_SIZE)) {
 123         flags |= BLK_MIG_FLAG_ZERO_BLOCK;
 124     }
 125
 126     /* sector number and flags */
 127     qemu_put_be64(f, (blk->sector << BDRV_SECTOR_BITS)
 128                      | flags);
 129
 130     /* device name */
 131     len = strlen(blk->bmds->bs->device_name);
 132     qemu_put_byte(f, len);
 133     qemu_put_buffer(f, (uint8_t *)blk->bmds->bs->device_name, len);
 134
 135     /* if a block is zero we need to flush here since the network
 136      * bandwidth is now a lot higher than the storage device bandwidth.
 137      * thus if we queue zero blocks we slow down the migration */
 138     if (flags & BLK_MIG_FLAG_ZERO_BLOCK) {
 139         qemu_fflush(f);
 140         return;
 141     }
 142
 143     qemu_put_buffer(f, blk->buf, BLOCK_SIZE);
 144 }
 145
 146 int blk_mig_active(void)
 147 {
 148     return !QSIMPLEQ_EMPTY(&block_mig_state.bmds_list);
 149 }
 150
 151 uint64_t blk_mig_bytes_transferred(void)
 152 {
 153     BlkMigDevState *bmds;
 154     uint64_t sum = 0;
 155
 156     blk_mig_lock();
 157     QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
 158         sum += bmds->completed_sectors;
 159     }
 160     blk_mig_unlock();
 161     return sum << BDRV_SECTOR_BITS;
 162 }
 163
 164 uint64_t blk_mig_bytes_remaining(void)
 165 {
 166     return blk_mig_bytes_total() - blk_mig_bytes_transferred();
 167 }
 168
 169 uint64_t blk_mig_bytes_total(void)
 170 {
 171     BlkMigDevState *bmds;
 172     uint64_t sum = 0;
 173
 174     QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
 175         sum += bmds->total_sectors;
 176     }
 177     return sum << BDRV_SECTOR_BITS;
 178 }
 179
 180
 181 /* Called with migration lock held.  */
 182
 183 static int bmds_aio_inflight(BlkMigDevState *bmds, int64_t sector)
 184 {
 185     int64_t chunk = sector / (int64_t)BDRV_SECTORS_PER_DIRTY_CHUNK;
 186
 187     if ((sector << BDRV_SECTOR_BITS) < bdrv_getlength(bmds->bs)) {
 188         return !!(bmds->aio_bitmap[chunk / (sizeof(unsigned long) * 8)] &
 189             (1UL << (chunk % (sizeof(unsigned long) * 8))));
 190     } else {
 191         return 0;
 192     }
 193 }
 194
 195 /* Called with migration lock held.  */
 196
 197 static void bmds_set_aio_inflight(BlkMigDevState *bmds, int64_t sector_num,
 198                              int nb_sectors, int set)
 199 {
 200     int64_t start, end;
 201     unsigned long val, idx, bit;
 202
 203     start = sector_num / BDRV_SECTORS_PER_DIRTY_CHUNK;
 204     end = (sector_num + nb_sectors - 1) / BDRV_SECTORS_PER_DIRTY_CHUNK;
 205
 206     for (; start <= end; start++) {
 207         idx = start / (sizeof(unsigned long) * 8);
 208         bit = start % (sizeof(unsigned long) * 8);
 209         val = bmds->aio_bitmap[idx];
 210         if (set) {
 211             val |= 1UL << bit;
 212         } else {
 213             val &= ~(1UL << bit);
 214         }
 215         bmds->aio_bitmap[idx] = val;
 216     }
 217 }
 218
 219 static void alloc_aio_bitmap(BlkMigDevState *bmds)
 220 {
 221     BlockDriverState *bs = bmds->bs;
 222     int64_t bitmap_size;
 223
 224     bitmap_size = (bdrv_getlength(bs) >> BDRV_SECTOR_BITS) +
 225             BDRV_SECTORS_PER_DIRTY_CHUNK * 8 - 1;
 226     bitmap_size /= BDRV_SECTORS_PER_DIRTY_CHUNK * 8;
 227
 228     bmds->aio_bitmap = g_malloc0(bitmap_size);
 229 }
 230
 231 /* Never hold migration lock when yielding to the main loop!  */
 232
 233 static void blk_mig_read_cb(void *opaque, int ret)
 234 {
 235     BlkMigBlock *blk = opaque;
 236
 237     blk_mig_lock();
 238     blk->ret = ret;
 239
 240     QSIMPLEQ_INSERT_TAIL(&block_mig_state.blk_list, blk, entry);
 241     bmds_set_aio_inflight(blk->bmds, blk->sector, blk->nr_sectors, 0);
 242
 243     block_mig_state.submitted--;
 244     block_mig_state.read_done++;
 245     assert(block_mig_state.submitted >= 0);
 246     blk_mig_unlock();
 247 }
 248
 249 /* Called with no lock taken.  */
 250
 251 static int mig_save_device_bulk(QEMUFile *f, BlkMigDevState *bmds)
 252 {
 253     int64_t total_sectors = bmds->total_sectors;
 254     int64_t cur_sector = bmds->cur_sector;
 255     BlockDriverState *bs = bmds->bs;
 256     BlkMigBlock *blk;
 257     int nr_sectors;
 258
 259     if (bmds->shared_base) {
 260         qemu_mutex_lock_iothread();
 261         while (cur_sector < total_sectors &&
 262                !bdrv_is_allocated(bs, cur_sector, MAX_IS_ALLOCATED_SEARCH,
 263                                   &nr_sectors)) {
 264             cur_sector += nr_sectors;
 265         }
 266         qemu_mutex_unlock_iothread();
 267     }
 268
 269     if (cur_sector >= total_sectors) {
 270         bmds->cur_sector = bmds->completed_sectors = total_sectors;
 271         return 1;
 272     }
 273
 274     bmds->completed_sectors = cur_sector;
 275
 276     cur_sector &= ~((int64_t)BDRV_SECTORS_PER_DIRTY_CHUNK - 1);
 277
 278     /* we are going to transfer a full block even if it is not allocated */
 279     nr_sectors = BDRV_SECTORS_PER_DIRTY_CHUNK;
 280
 281     if (total_sectors - cur_sector < BDRV_SECTORS_PER_DIRTY_CHUNK) {
 282         nr_sectors = total_sectors - cur_sector;
 283     }
 284
 285     blk = g_malloc(sizeof(BlkMigBlock));
 286     blk->buf = g_malloc(BLOCK_SIZE);
 287     blk->bmds = bmds;
 288     blk->sector = cur_sector;
 289     blk->nr_sectors = nr_sectors;
 290
 291     blk->iov.iov_base = blk->buf;
 292     blk->iov.iov_len = nr_sectors * BDRV_SECTOR_SIZE;
 293     qemu_iovec_init_external(&blk->qiov, &blk->iov, 1);
 294
 295     blk_mig_lock();
 296     block_mig_state.submitted++;
 297     blk_mig_unlock();
 298
 299     qemu_mutex_lock_iothread();
 300     blk->aiocb = bdrv_aio_readv(bs, cur_sector, &blk->qiov,
 301                                 nr_sectors, blk_mig_read_cb, blk);
 302
 303     bdrv_reset_dirty(bs, cur_sector, nr_sectors);
 304     qemu_mutex_unlock_iothread();
 305
 306     bmds->cur_sector = cur_sector + nr_sectors;
 307     return (bmds->cur_sector >= total_sectors);
 308 }
 309
 310 /* Called with iothread lock taken.  */
 311
 312 static void set_dirty_tracking(int enable)
 313 {
 314     BlkMigDevState *bmds;
 315
 316     QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
 317         bdrv_set_dirty_tracking(bmds->bs, enable ? BLOCK_SIZE : 0);
 318     }
 319 }
 320
 321 static void init_blk_migration_it(void *opaque, BlockDriverState *bs)
 322 {
 323     BlkMigDevState *bmds;
 324     int64_t sectors;
 325
 326     if (!bdrv_is_read_only(bs)) {
 327         sectors = bdrv_getlength(bs) >> BDRV_SECTOR_BITS;
 328         if (sectors <= 0) {
 329             return;
 330         }
 331
 332         bmds = g_malloc0(sizeof(BlkMigDevState));
 333         bmds->bs = bs;
 334         bmds->bulk_completed = 0;
 335         bmds->total_sectors = sectors;
 336         bmds->completed_sectors = 0;
 337         bmds->shared_base = block_mig_state.shared_base;
 338         alloc_aio_bitmap(bmds);
 339         drive_get_ref(drive_get_by_blockdev(bs));
 340         bdrv_set_in_use(bs, 1);
 341
 342         block_mig_state.total_sector_sum += sectors;
 343
 344         if (bmds->shared_base) {
 345             DPRINTF("Start migration for %s with shared base image\n",
 346                     bs->device_name);
 347         } else {
 348             DPRINTF("Start full migration for %s\n", bs->device_name);
 349         }
 350
 351         QSIMPLEQ_INSERT_TAIL(&block_mig_state.bmds_list, bmds, entry);
 352     }
 353 }
 354
 355 static void init_blk_migration(QEMUFile *f)
 356 {
 357     block_mig_state.submitted = 0;
 358     block_mig_state.read_done = 0;
 359     block_mig_state.transferred = 0;
 360     block_mig_state.total_sector_sum = 0;
 361     block_mig_state.prev_progress = -1;
 362     block_mig_state.bulk_completed = 0;
 363     block_mig_state.zero_blocks = migrate_zero_blocks();
 364
 365     bdrv_iterate(init_blk_migration_it, NULL);
 366 }
 367
 368 /* Called with no lock taken.  */
 369
 370 static int blk_mig_save_bulked_block(QEMUFile *f)
 371 {
 372     int64_t completed_sector_sum = 0;
 373     BlkMigDevState *bmds;
 374     int progress;
 375     int ret = 0;
 376
 377     QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
 378         if (bmds->bulk_completed == 0) {
 379             if (mig_save_device_bulk(f, bmds) == 1) {
 380                 /* completed bulk section for this device */
 381                 bmds->bulk_completed = 1;
 382             }
 383             completed_sector_sum += bmds->completed_sectors;
 384             ret = 1;
 385             break;
 386         } else {
 387             completed_sector_sum += bmds->completed_sectors;
 388         }
 389     }
 390
 391     if (block_mig_state.total_sector_sum != 0) {
 392         progress = completed_sector_sum * 100 /
 393                    block_mig_state.total_sector_sum;
 394     } else {
 395         progress = 100;
 396     }
 397     if (progress != block_mig_state.prev_progress) {
 398         block_mig_state.prev_progress = progress;
 399         qemu_put_be64(f, (progress << BDRV_SECTOR_BITS)
 400                          | BLK_MIG_FLAG_PROGRESS);
 401         DPRINTF("Completed %d %%\r", progress);
 402     }
 403
 404     return ret;
 405 }
 406
 407 static void blk_mig_reset_dirty_cursor(void)
 408 {
 409     BlkMigDevState *bmds;
 410
 411     QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
 412         bmds->cur_dirty = 0;
 413     }
 414 }
 415
 416 /* Called with iothread lock taken.  */
 417
 418 static int mig_save_device_dirty(QEMUFile *f, BlkMigDevState *bmds,
 419                                  int is_async)
 420 {
 421     BlkMigBlock *blk;
 422     int64_t total_sectors = bmds->total_sectors;
 423     int64_t sector;
 424     int nr_sectors;
 425     int ret = -EIO;
 426
 427     for (sector = bmds->cur_dirty; sector < bmds->total_sectors;) {
 428         blk_mig_lock();
 429         if (bmds_aio_inflight(bmds, sector)) {
 430             blk_mig_unlock();
 431             bdrv_drain_all();
 432         } else {
 433             blk_mig_unlock();
 434         }
 435         if (bdrv_get_dirty(bmds->bs, sector)) {
 436
 437             if (total_sectors - sector < BDRV_SECTORS_PER_DIRTY_CHUNK) {
 438                 nr_sectors = total_sectors - sector;
 439             } else {
 440                 nr_sectors = BDRV_SECTORS_PER_DIRTY_CHUNK;
 441             }
 442             blk = g_malloc(sizeof(BlkMigBlock));
 443             blk->buf = g_malloc(BLOCK_SIZE);
 444             blk->bmds = bmds;
 445             blk->sector = sector;
 446             blk->nr_sectors = nr_sectors;
 447
 448             if (is_async) {
 449                 blk->iov.iov_base = blk->buf;
 450                 blk->iov.iov_len = nr_sectors * BDRV_SECTOR_SIZE;
 451                 qemu_iovec_init_external(&blk->qiov, &blk->iov, 1);
 452
 453                 blk->aiocb = bdrv_aio_readv(bmds->bs, sector, &blk->qiov,
 454                                             nr_sectors, blk_mig_read_cb, blk);
 455
 456                 blk_mig_lock();
 457                 block_mig_state.submitted++;
 458                 bmds_set_aio_inflight(bmds, sector, nr_sectors, 1);
 459                 blk_mig_unlock();
 460             } else {
 461                 ret = bdrv_read(bmds->bs, sector, blk->buf, nr_sectors);
 462                 if (ret < 0) {
 463                     goto error;
 464                 }
 465                 blk_send(f, blk);
 466
 467                 g_free(blk->buf);
 468                 g_free(blk);
 469             }
 470
 471             bdrv_reset_dirty(bmds->bs, sector, nr_sectors);
 472             break;
 473         }
 474         sector += BDRV_SECTORS_PER_DIRTY_CHUNK;
 475         bmds->cur_dirty = sector;
 476     }
 477
 478     return (bmds->cur_dirty >= bmds->total_sectors);
 479
 480 error:
 481     DPRINTF("Error reading sector %" PRId64 "\n", sector);
 482     g_free(blk->buf);
 483     g_free(blk);
 484     return ret;
 485 }
 486
 487 /* Called with iothread lock taken.
 488  *
 489  * return value:
 490  * 0: too much data for max_downtime
 491  * 1: few enough data for max_downtime
 492 */
 493 static int blk_mig_save_dirty_block(QEMUFile *f, int is_async)
 494 {
 495     BlkMigDevState *bmds;
 496     int ret = 1;
 497
 498     QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
 499         ret = mig_save_device_dirty(f, bmds, is_async);
 500         if (ret <= 0) {
 501             break;
 502         }
 503     }
 504
 505     return ret;
 506 }
 507
 508 /* Called with no locks taken.  */
 509
 510 static int flush_blks(QEMUFile *f)
 511 {
 512     BlkMigBlock *blk;
 513     int ret = 0;
 514
 515     DPRINTF("%s Enter submitted %d read_done %d transferred %d\n",
 516             __FUNCTION__, block_mig_state.submitted, block_mig_state.read_done,
 517             block_mig_state.transferred);
 518
 519     blk_mig_lock();
 520     while ((blk = QSIMPLEQ_FIRST(&block_mig_state.blk_list)) != NULL) {
 521         if (qemu_file_rate_limit(f)) {
 522             break;
 523         }
 524         if (blk->ret < 0) {
 525             ret = blk->ret;
 526             break;
 527         }
 528
 529         QSIMPLEQ_REMOVE_HEAD(&block_mig_state.blk_list, entry);
 530         blk_mig_unlock();
 531         blk_send(f, blk);
 532         blk_mig_lock();
 533
 534         g_free(blk->buf);
 535         g_free(blk);
 536
 537         block_mig_state.read_done--;
 538         block_mig_state.transferred++;
 539         assert(block_mig_state.read_done >= 0);
 540     }
 541     blk_mig_unlock();
 542
 543     DPRINTF("%s Exit submitted %d read_done %d transferred %d\n", __FUNCTION__,
 544             block_mig_state.submitted, block_mig_state.read_done,
 545             block_mig_state.transferred);
 546     return ret;
 547 }
 548
 549 /* Called with iothread lock taken.  */
 550
 551 static int64_t get_remaining_dirty(void)
 552 {
 553     BlkMigDevState *bmds;
 554     int64_t dirty = 0;
 555
 556     QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
 557         dirty += bdrv_get_dirty_count(bmds->bs);
 558     }
 559
 560     return dirty << BDRV_SECTOR_BITS;
 561 }
 562
 563 /* Called with iothread lock taken.  */
 564
 565 static void blk_mig_cleanup(void)
 566 {
 567     BlkMigDevState *bmds;
 568     BlkMigBlock *blk;
 569
 570     bdrv_drain_all();
 571
 572     set_dirty_tracking(0);
 573
 574     blk_mig_lock();
 575     while ((bmds = QSIMPLEQ_FIRST(&block_mig_state.bmds_list)) != NULL) {
 576         QSIMPLEQ_REMOVE_HEAD(&block_mig_state.bmds_list, entry);
 577         bdrv_set_in_use(bmds->bs, 0);
 578         drive_put_ref(drive_get_by_blockdev(bmds->bs));
 579         g_free(bmds->aio_bitmap);
 580         g_free(bmds);
 581     }
 582
 583     while ((blk = QSIMPLEQ_FIRST(&block_mig_state.blk_list)) != NULL) {
 584         QSIMPLEQ_REMOVE_HEAD(&block_mig_state.blk_list, entry);
 585         g_free(blk->buf);
 586         g_free(blk);
 587     }
 588     blk_mig_unlock();
 589 }
 590
 591 static void block_migration_cancel(void *opaque)
 592 {
 593     blk_mig_cleanup();
 594 }
 595
 596 static int block_save_setup(QEMUFile *f, void *opaque)
 597 {
 598     int ret;
 599
 600     DPRINTF("Enter save live setup submitted %d transferred %d\n",
 601             block_mig_state.submitted, block_mig_state.transferred);
 602
 603     qemu_mutex_lock_iothread();
 604     init_blk_migration(f);
 605
 606     /* start track dirty blocks */
 607     set_dirty_tracking(1);
 608     qemu_mutex_unlock_iothread();
 609
 610     ret = flush_blks(f);
 611     blk_mig_reset_dirty_cursor();
 612     qemu_put_be64(f, BLK_MIG_FLAG_EOS);
 613
 614     return ret;
 615 }
 616
 617 static int block_save_iterate(QEMUFile *f, void *opaque)
 618 {
 619     int ret;
 620     int64_t last_ftell = qemu_ftell(f);
 621
 622     DPRINTF("Enter save live iterate submitted %d transferred %d\n",
 623             block_mig_state.submitted, block_mig_state.transferred);
 624
 625     ret = flush_blks(f);
 626     if (ret) {
 627         return ret;
 628     }
 629
 630     blk_mig_reset_dirty_cursor();
 631
 632     /* control the rate of transfer */
 633     blk_mig_lock();
 634     while ((block_mig_state.submitted +
 635             block_mig_state.read_done) * BLOCK_SIZE <
 636            qemu_file_get_rate_limit(f)) {
 637         blk_mig_unlock();
 638         if (block_mig_state.bulk_completed == 0) {
 639             /* first finish the bulk phase */
 640             if (blk_mig_save_bulked_block(f) == 0) {
 641                 /* finished saving bulk on all devices */
 642                 block_mig_state.bulk_completed = 1;
 643             }
 644             ret = 0;
 645         } else {
 646             /* Always called with iothread lock taken for
 647              * simplicity, block_save_complete also calls it.
 648              */
 649             qemu_mutex_lock_iothread();
 650             ret = blk_mig_save_dirty_block(f, 1);
 651             qemu_mutex_unlock_iothread();
 652         }
 653         if (ret < 0) {
 654             return ret;
 655         }
 656         blk_mig_lock();
 657         if (ret != 0) {
 658             /* no more dirty blocks */
 659             break;
 660         }
 661     }
 662     blk_mig_unlock();
 663
 664     ret = flush_blks(f);
 665     if (ret) {
 666         return ret;
 667     }
 668
 669     qemu_put_be64(f, BLK_MIG_FLAG_EOS);
 670     return qemu_ftell(f) - last_ftell;
 671 }
 672
 673 /* Called with iothread lock taken.  */
 674
 675 static int block_save_complete(QEMUFile *f, void *opaque)
 676 {
 677     int ret;
 678
 679     DPRINTF("Enter save live complete submitted %d transferred %d\n",
 680             block_mig_state.submitted, block_mig_state.transferred);
 681
 682     ret = flush_blks(f);
 683     if (ret) {
 684         return ret;
 685     }
 686
 687     blk_mig_reset_dirty_cursor();
 688
 689     /* we know for sure that save bulk is completed and
 690        all async read completed */
 691     blk_mig_lock();
 692     assert(block_mig_state.submitted == 0);
 693     blk_mig_unlock();
 694
 695     do {
 696         ret = blk_mig_save_dirty_block(f, 0);
 697         if (ret < 0) {
 698             return ret;
 699         }
 700     } while (ret == 0);
 701
 702     /* report completion */
 703     qemu_put_be64(f, (100 << BDRV_SECTOR_BITS) | BLK_MIG_FLAG_PROGRESS);
 704
 705     DPRINTF("Block migration completed\n");
 706
 707     qemu_put_be64(f, BLK_MIG_FLAG_EOS);
 708
 709     blk_mig_cleanup();
 710     return 0;
 711 }
 712
 713 static uint64_t block_save_pending(QEMUFile *f, void *opaque, uint64_t max_size)
 714 {
 715     /* Estimate pending number of bytes to send */
 716     uint64_t pending;
 717
 718     qemu_mutex_lock_iothread();
 719     blk_mig_lock();
 720     pending = get_remaining_dirty() +
 721                        block_mig_state.submitted * BLOCK_SIZE +
 722                        block_mig_state.read_done * BLOCK_SIZE;
 723
 724     /* Report at least one block pending during bulk phase */
 725     if (pending == 0 && !block_mig_state.bulk_completed) {
 726         pending = BLOCK_SIZE;
 727     }
 728     blk_mig_unlock();
 729     qemu_mutex_unlock_iothread();
 730
 731     DPRINTF("Enter save live pending  %" PRIu64 "\n", pending);
 732     return pending;
 733 }
 734
 735 static int block_load(QEMUFile *f, void *opaque, int version_id)
 736 {
 737     static int banner_printed;
 738     int len, flags;
 739     char device_name[256];
 740     int64_t addr;
 741     BlockDriverState *bs, *bs_prev = NULL;
 742     uint8_t *buf;
 743     int64_t total_sectors = 0;
 744     int nr_sectors;
 745     int ret;
 746
 747     do {
 748         addr = qemu_get_be64(f);
 749
 750         flags = addr & ~BDRV_SECTOR_MASK;
 751         addr >>= BDRV_SECTOR_BITS;
 752
 753         if (flags & BLK_MIG_FLAG_DEVICE_BLOCK) {
 754             /* get device name */
 755             len = qemu_get_byte(f);
 756             qemu_get_buffer(f, (uint8_t *)device_name, len);
 757             device_name[len] = '\0';
 758
 759             bs = bdrv_find(device_name);
 760             if (!bs) {
 761                 fprintf(stderr, "Error unknown block device %s\n",
 762                         device_name);
 763                 return -EINVAL;
 764             }
 765
 766             if (bs != bs_prev) {
 767                 bs_prev = bs;
 768                 total_sectors = bdrv_getlength(bs) >> BDRV_SECTOR_BITS;
 769                 if (total_sectors <= 0) {
 770                     error_report("Error getting length of block device %s",
 771                                  device_name);
 772                     return -EINVAL;
 773                 }
 774             }
 775
 776             if (total_sectors - addr < BDRV_SECTORS_PER_DIRTY_CHUNK) {
 777                 nr_sectors = total_sectors - addr;
 778             } else {
 779                 nr_sectors = BDRV_SECTORS_PER_DIRTY_CHUNK;
 780             }
 781
 782             if (flags & BLK_MIG_FLAG_ZERO_BLOCK) {
 783                 ret = bdrv_write_zeroes(bs, addr, nr_sectors);
 784             } else {
 785                 buf = g_malloc(BLOCK_SIZE);
 786                 qemu_get_buffer(f, buf, BLOCK_SIZE);
 787                 ret = bdrv_write(bs, addr, buf, nr_sectors);
 788                 g_free(buf);
 789             }
 790
 791             if (ret < 0) {
 792                 return ret;
 793             }
 794         } else if (flags & BLK_MIG_FLAG_PROGRESS) {
 795             if (!banner_printed) {
 796                 printf("Receiving block device images\n");
 797                 banner_printed = 1;
 798             }
 799             printf("Completed %d %%%c", (int)addr,
 800                    (addr == 100) ? '\n' : '\r');
 801             fflush(stdout);
 802         } else if (!(flags & BLK_MIG_FLAG_EOS)) {
 803             fprintf(stderr, "Unknown block migration flags: %#x\n", flags);
 804             return -EINVAL;
 805         }
 806         ret = qemu_file_get_error(f);
 807         if (ret != 0) {
 808             return ret;
 809         }
 810     } while (!(flags & BLK_MIG_FLAG_EOS));
 811
 812     return 0;
 813 }
 814
 815 static void block_set_params(const MigrationParams *params, void *opaque)
 816 {
 817     block_mig_state.blk_enable = params->blk;
 818     block_mig_state.shared_base = params->shared;
 819
 820     /* shared base means that blk_enable = 1 */
 821     block_mig_state.blk_enable |= params->shared;
 822 }
 823
 824 static bool block_is_active(void *opaque)
 825 {
 826     return block_mig_state.blk_enable == 1;
 827 }
 828
 829 SaveVMHandlers savevm_block_handlers = {
 830     .set_params = block_set_params,
 831     .save_live_setup = block_save_setup,
 832     .save_live_iterate = block_save_iterate,
 833     .save_live_complete = block_save_complete,
 834     .save_live_pending = block_save_pending,
 835     .load_state = block_load,
 836     .cancel = block_migration_cancel,
 837     .is_active = block_is_active,
 838 };
 839
 840 void blk_mig_init(void)
 841 {
 842     QSIMPLEQ_INIT(&block_mig_state.bmds_list);
 843     QSIMPLEQ_INIT(&block_mig_state.blk_list);
 844     qemu_mutex_init(&block_mig_state.lock);
 845
 846     register_savevm_live(NULL, "block", 0, 1, &savevm_block_handlers,
 847                          &block_mig_state);
 848 }