hw/misc/led: Add yellow LED
[qemu/ar7.git] / migration / block.c
bloba950977855281bb0b3de321f1432462485a9d62f
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  */
16 #include "qemu/osdep.h"
17 #include "qapi/error.h"
18 #include "qemu/error-report.h"
19 #include "qemu/main-loop.h"
20 #include "qemu/cutils.h"
21 #include "qemu/queue.h"
22 #include "block.h"
23 #include "migration/misc.h"
24 #include "migration.h"
25 #include "migration/register.h"
26 #include "qemu-file.h"
27 #include "migration/vmstate.h"
28 #include "sysemu/block-backend.h"
29 #include "trace.h"
31 #define BLK_MIG_BLOCK_SIZE           (1 << 20)
32 #define BDRV_SECTORS_PER_DIRTY_CHUNK (BLK_MIG_BLOCK_SIZE >> BDRV_SECTOR_BITS)
34 #define BLK_MIG_FLAG_DEVICE_BLOCK       0x01
35 #define BLK_MIG_FLAG_EOS                0x02
36 #define BLK_MIG_FLAG_PROGRESS           0x04
37 #define BLK_MIG_FLAG_ZERO_BLOCK         0x08
39 #define MAX_IS_ALLOCATED_SEARCH (65536 * BDRV_SECTOR_SIZE)
41 #define MAX_IO_BUFFERS 512
42 #define MAX_PARALLEL_IO 16
44 /* #define DEBUG_BLK_MIGRATION */
46 #ifdef DEBUG_BLK_MIGRATION
47 #define DPRINTF(fmt, ...) \
48     do { printf("blk_migration: " fmt, ## __VA_ARGS__); } while (0)
49 #else
50 #define DPRINTF(fmt, ...) \
51     do { } while (0)
52 #endif
54 typedef struct BlkMigDevState {
55     /* Written during setup phase.  Can be read without a lock.  */
56     BlockBackend *blk;
57     char *blk_name;
58     int shared_base;
59     int64_t total_sectors;
60     QSIMPLEQ_ENTRY(BlkMigDevState) entry;
61     Error *blocker;
63     /* Only used by migration thread.  Does not need a lock.  */
64     int bulk_completed;
65     int64_t cur_sector;
66     int64_t cur_dirty;
68     /* Data in the aio_bitmap is protected by block migration lock.
69      * Allocation and free happen during setup and cleanup respectively.
70      */
71     unsigned long *aio_bitmap;
73     /* Protected by block migration lock.  */
74     int64_t completed_sectors;
76     /* During migration this is protected by iothread lock / AioContext.
77      * Allocation and free happen during setup and cleanup respectively.
78      */
79     BdrvDirtyBitmap *dirty_bitmap;
80 } BlkMigDevState;
82 typedef struct BlkMigBlock {
83     /* Only used by migration thread.  */
84     uint8_t *buf;
85     BlkMigDevState *bmds;
86     int64_t sector;
87     int nr_sectors;
88     QEMUIOVector qiov;
89     BlockAIOCB *aiocb;
91     /* Protected by block migration lock.  */
92     int ret;
93     QSIMPLEQ_ENTRY(BlkMigBlock) entry;
94 } BlkMigBlock;
96 typedef struct BlkMigState {
97     QSIMPLEQ_HEAD(, BlkMigDevState) bmds_list;
98     int64_t total_sector_sum;
99     bool zero_blocks;
101     /* Protected by lock.  */
102     QSIMPLEQ_HEAD(, BlkMigBlock) blk_list;
103     int submitted;
104     int read_done;
106     /* Only used by migration thread.  Does not need a lock.  */
107     int transferred;
108     int prev_progress;
109     int bulk_completed;
111     /* Lock must be taken _inside_ the iothread lock and any AioContexts.  */
112     QemuMutex lock;
113 } BlkMigState;
115 static BlkMigState block_mig_state;
117 static void blk_mig_lock(void)
119     qemu_mutex_lock(&block_mig_state.lock);
122 static void blk_mig_unlock(void)
124     qemu_mutex_unlock(&block_mig_state.lock);
127 /* Must run outside of the iothread lock during the bulk phase,
128  * or the VM will stall.
129  */
131 static void blk_send(QEMUFile *f, BlkMigBlock * blk)
133     int len;
134     uint64_t flags = BLK_MIG_FLAG_DEVICE_BLOCK;
136     if (block_mig_state.zero_blocks &&
137         buffer_is_zero(blk->buf, BLK_MIG_BLOCK_SIZE)) {
138         flags |= BLK_MIG_FLAG_ZERO_BLOCK;
139     }
141     /* sector number and flags */
142     qemu_put_be64(f, (blk->sector << BDRV_SECTOR_BITS)
143                      | flags);
145     /* device name */
146     len = strlen(blk->bmds->blk_name);
147     qemu_put_byte(f, len);
148     qemu_put_buffer(f, (uint8_t *) blk->bmds->blk_name, len);
150     /* if a block is zero we need to flush here since the network
151      * bandwidth is now a lot higher than the storage device bandwidth.
152      * thus if we queue zero blocks we slow down the migration */
153     if (flags & BLK_MIG_FLAG_ZERO_BLOCK) {
154         qemu_fflush(f);
155         return;
156     }
158     qemu_put_buffer(f, blk->buf, BLK_MIG_BLOCK_SIZE);
161 int blk_mig_active(void)
163     return !QSIMPLEQ_EMPTY(&block_mig_state.bmds_list);
166 int blk_mig_bulk_active(void)
168     return blk_mig_active() && !block_mig_state.bulk_completed;
171 uint64_t blk_mig_bytes_transferred(void)
173     BlkMigDevState *bmds;
174     uint64_t sum = 0;
176     blk_mig_lock();
177     QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
178         sum += bmds->completed_sectors;
179     }
180     blk_mig_unlock();
181     return sum << BDRV_SECTOR_BITS;
184 uint64_t blk_mig_bytes_remaining(void)
186     return blk_mig_bytes_total() - blk_mig_bytes_transferred();
189 uint64_t blk_mig_bytes_total(void)
191     BlkMigDevState *bmds;
192     uint64_t sum = 0;
194     QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
195         sum += bmds->total_sectors;
196     }
197     return sum << BDRV_SECTOR_BITS;
201 /* Called with migration lock held.  */
203 static int bmds_aio_inflight(BlkMigDevState *bmds, int64_t sector)
205     int64_t chunk = sector / (int64_t)BDRV_SECTORS_PER_DIRTY_CHUNK;
207     if (sector < blk_nb_sectors(bmds->blk)) {
208         return !!(bmds->aio_bitmap[chunk / (sizeof(unsigned long) * 8)] &
209             (1UL << (chunk % (sizeof(unsigned long) * 8))));
210     } else {
211         return 0;
212     }
215 /* Called with migration lock held.  */
217 static void bmds_set_aio_inflight(BlkMigDevState *bmds, int64_t sector_num,
218                              int nb_sectors, int set)
220     int64_t start, end;
221     unsigned long val, idx, bit;
223     start = sector_num / BDRV_SECTORS_PER_DIRTY_CHUNK;
224     end = (sector_num + nb_sectors - 1) / BDRV_SECTORS_PER_DIRTY_CHUNK;
226     for (; start <= end; start++) {
227         idx = start / (sizeof(unsigned long) * 8);
228         bit = start % (sizeof(unsigned long) * 8);
229         val = bmds->aio_bitmap[idx];
230         if (set) {
231             val |= 1UL << bit;
232         } else {
233             val &= ~(1UL << bit);
234         }
235         bmds->aio_bitmap[idx] = val;
236     }
239 static void alloc_aio_bitmap(BlkMigDevState *bmds)
241     BlockBackend *bb = bmds->blk;
242     int64_t bitmap_size;
244     bitmap_size = blk_nb_sectors(bb) + BDRV_SECTORS_PER_DIRTY_CHUNK * 8 - 1;
245     bitmap_size /= BDRV_SECTORS_PER_DIRTY_CHUNK * 8;
247     bmds->aio_bitmap = g_malloc0(bitmap_size);
250 /* Never hold migration lock when yielding to the main loop!  */
252 static void blk_mig_read_cb(void *opaque, int ret)
254     BlkMigBlock *blk = opaque;
256     blk_mig_lock();
257     blk->ret = ret;
259     QSIMPLEQ_INSERT_TAIL(&block_mig_state.blk_list, blk, entry);
260     bmds_set_aio_inflight(blk->bmds, blk->sector, blk->nr_sectors, 0);
262     block_mig_state.submitted--;
263     block_mig_state.read_done++;
264     assert(block_mig_state.submitted >= 0);
265     blk_mig_unlock();
268 /* Called with no lock taken.  */
270 static int mig_save_device_bulk(QEMUFile *f, BlkMigDevState *bmds)
272     int64_t total_sectors = bmds->total_sectors;
273     int64_t cur_sector = bmds->cur_sector;
274     BlockBackend *bb = bmds->blk;
275     BlkMigBlock *blk;
276     int nr_sectors;
277     int64_t count;
279     if (bmds->shared_base) {
280         qemu_mutex_lock_iothread();
281         aio_context_acquire(blk_get_aio_context(bb));
282         /* Skip unallocated sectors; intentionally treats failure or
283          * partial sector as an allocated sector */
284         while (cur_sector < total_sectors &&
285                !bdrv_is_allocated(blk_bs(bb), cur_sector * BDRV_SECTOR_SIZE,
286                                   MAX_IS_ALLOCATED_SEARCH, &count)) {
287             if (count < BDRV_SECTOR_SIZE) {
288                 break;
289             }
290             cur_sector += count >> BDRV_SECTOR_BITS;
291         }
292         aio_context_release(blk_get_aio_context(bb));
293         qemu_mutex_unlock_iothread();
294     }
296     if (cur_sector >= total_sectors) {
297         bmds->cur_sector = bmds->completed_sectors = total_sectors;
298         return 1;
299     }
301     bmds->completed_sectors = cur_sector;
303     cur_sector &= ~((int64_t)BDRV_SECTORS_PER_DIRTY_CHUNK - 1);
305     /* we are going to transfer a full block even if it is not allocated */
306     nr_sectors = BDRV_SECTORS_PER_DIRTY_CHUNK;
308     if (total_sectors - cur_sector < BDRV_SECTORS_PER_DIRTY_CHUNK) {
309         nr_sectors = total_sectors - cur_sector;
310     }
312     blk = g_new(BlkMigBlock, 1);
313     blk->buf = g_malloc(BLK_MIG_BLOCK_SIZE);
314     blk->bmds = bmds;
315     blk->sector = cur_sector;
316     blk->nr_sectors = nr_sectors;
318     qemu_iovec_init_buf(&blk->qiov, blk->buf, nr_sectors * BDRV_SECTOR_SIZE);
320     blk_mig_lock();
321     block_mig_state.submitted++;
322     blk_mig_unlock();
324     /* We do not know if bs is under the main thread (and thus does
325      * not acquire the AioContext when doing AIO) or rather under
326      * dataplane.  Thus acquire both the iothread mutex and the
327      * AioContext.
328      *
329      * This is ugly and will disappear when we make bdrv_* thread-safe,
330      * without the need to acquire the AioContext.
331      */
332     qemu_mutex_lock_iothread();
333     aio_context_acquire(blk_get_aio_context(bmds->blk));
334     bdrv_reset_dirty_bitmap(bmds->dirty_bitmap, cur_sector * BDRV_SECTOR_SIZE,
335                             nr_sectors * BDRV_SECTOR_SIZE);
336     blk->aiocb = blk_aio_preadv(bb, cur_sector * BDRV_SECTOR_SIZE, &blk->qiov,
337                                 0, blk_mig_read_cb, blk);
338     aio_context_release(blk_get_aio_context(bmds->blk));
339     qemu_mutex_unlock_iothread();
341     bmds->cur_sector = cur_sector + nr_sectors;
342     return (bmds->cur_sector >= total_sectors);
345 /* Called with iothread lock taken.  */
347 static int set_dirty_tracking(void)
349     BlkMigDevState *bmds;
350     int ret;
352     QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
353         bmds->dirty_bitmap = bdrv_create_dirty_bitmap(blk_bs(bmds->blk),
354                                                       BLK_MIG_BLOCK_SIZE,
355                                                       NULL, NULL);
356         if (!bmds->dirty_bitmap) {
357             ret = -errno;
358             goto fail;
359         }
360     }
361     return 0;
363 fail:
364     QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
365         if (bmds->dirty_bitmap) {
366             bdrv_release_dirty_bitmap(bmds->dirty_bitmap);
367         }
368     }
369     return ret;
372 /* Called with iothread lock taken.  */
374 static void unset_dirty_tracking(void)
376     BlkMigDevState *bmds;
378     QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
379         bdrv_release_dirty_bitmap(bmds->dirty_bitmap);
380     }
383 static int init_blk_migration(QEMUFile *f)
385     BlockDriverState *bs;
386     BlkMigDevState *bmds;
387     int64_t sectors;
388     BdrvNextIterator it;
389     int i, num_bs = 0;
390     struct {
391         BlkMigDevState *bmds;
392         BlockDriverState *bs;
393     } *bmds_bs;
394     Error *local_err = NULL;
395     int ret;
397     block_mig_state.submitted = 0;
398     block_mig_state.read_done = 0;
399     block_mig_state.transferred = 0;
400     block_mig_state.total_sector_sum = 0;
401     block_mig_state.prev_progress = -1;
402     block_mig_state.bulk_completed = 0;
403     block_mig_state.zero_blocks = migrate_zero_blocks();
405     for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
406         num_bs++;
407     }
408     bmds_bs = g_malloc0(num_bs * sizeof(*bmds_bs));
410     for (i = 0, bs = bdrv_first(&it); bs; bs = bdrv_next(&it), i++) {
411         if (bdrv_is_read_only(bs)) {
412             continue;
413         }
415         sectors = bdrv_nb_sectors(bs);
416         if (sectors <= 0) {
417             ret = sectors;
418             bdrv_next_cleanup(&it);
419             goto out;
420         }
422         bmds = g_new0(BlkMigDevState, 1);
423         bmds->blk = blk_new(qemu_get_aio_context(),
424                             BLK_PERM_CONSISTENT_READ, BLK_PERM_ALL);
425         bmds->blk_name = g_strdup(bdrv_get_device_name(bs));
426         bmds->bulk_completed = 0;
427         bmds->total_sectors = sectors;
428         bmds->completed_sectors = 0;
429         bmds->shared_base = migrate_use_block_incremental();
431         assert(i < num_bs);
432         bmds_bs[i].bmds = bmds;
433         bmds_bs[i].bs = bs;
435         block_mig_state.total_sector_sum += sectors;
437         if (bmds->shared_base) {
438             trace_migration_block_init_shared(bdrv_get_device_name(bs));
439         } else {
440             trace_migration_block_init_full(bdrv_get_device_name(bs));
441         }
443         QSIMPLEQ_INSERT_TAIL(&block_mig_state.bmds_list, bmds, entry);
444     }
446     /* Can only insert new BDSes now because doing so while iterating block
447      * devices may end up in a deadlock (iterating the new BDSes, too). */
448     for (i = 0; i < num_bs; i++) {
449         BlkMigDevState *bmds = bmds_bs[i].bmds;
450         BlockDriverState *bs = bmds_bs[i].bs;
452         if (bmds) {
453             ret = blk_insert_bs(bmds->blk, bs, &local_err);
454             if (ret < 0) {
455                 error_report_err(local_err);
456                 goto out;
457             }
459             alloc_aio_bitmap(bmds);
460             error_setg(&bmds->blocker, "block device is in use by migration");
461             bdrv_op_block_all(bs, bmds->blocker);
462         }
463     }
465     ret = 0;
466 out:
467     g_free(bmds_bs);
468     return ret;
471 /* Called with no lock taken.  */
473 static int blk_mig_save_bulked_block(QEMUFile *f)
475     int64_t completed_sector_sum = 0;
476     BlkMigDevState *bmds;
477     int progress;
478     int ret = 0;
480     QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
481         if (bmds->bulk_completed == 0) {
482             if (mig_save_device_bulk(f, bmds) == 1) {
483                 /* completed bulk section for this device */
484                 bmds->bulk_completed = 1;
485             }
486             completed_sector_sum += bmds->completed_sectors;
487             ret = 1;
488             break;
489         } else {
490             completed_sector_sum += bmds->completed_sectors;
491         }
492     }
494     if (block_mig_state.total_sector_sum != 0) {
495         progress = completed_sector_sum * 100 /
496                    block_mig_state.total_sector_sum;
497     } else {
498         progress = 100;
499     }
500     if (progress != block_mig_state.prev_progress) {
501         block_mig_state.prev_progress = progress;
502         qemu_put_be64(f, (progress << BDRV_SECTOR_BITS)
503                          | BLK_MIG_FLAG_PROGRESS);
504         DPRINTF("Completed %d %%\r", progress);
505     }
507     return ret;
510 static void blk_mig_reset_dirty_cursor(void)
512     BlkMigDevState *bmds;
514     QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
515         bmds->cur_dirty = 0;
516     }
519 /* Called with iothread lock and AioContext taken.  */
521 static int mig_save_device_dirty(QEMUFile *f, BlkMigDevState *bmds,
522                                  int is_async)
524     BlkMigBlock *blk;
525     int64_t total_sectors = bmds->total_sectors;
526     int64_t sector;
527     int nr_sectors;
528     int ret = -EIO;
530     for (sector = bmds->cur_dirty; sector < bmds->total_sectors;) {
531         blk_mig_lock();
532         if (bmds_aio_inflight(bmds, sector)) {
533             blk_mig_unlock();
534             blk_drain(bmds->blk);
535         } else {
536             blk_mig_unlock();
537         }
538         bdrv_dirty_bitmap_lock(bmds->dirty_bitmap);
539         if (bdrv_dirty_bitmap_get_locked(bmds->dirty_bitmap,
540                                          sector * BDRV_SECTOR_SIZE)) {
541             if (total_sectors - sector < BDRV_SECTORS_PER_DIRTY_CHUNK) {
542                 nr_sectors = total_sectors - sector;
543             } else {
544                 nr_sectors = BDRV_SECTORS_PER_DIRTY_CHUNK;
545             }
546             bdrv_reset_dirty_bitmap_locked(bmds->dirty_bitmap,
547                                            sector * BDRV_SECTOR_SIZE,
548                                            nr_sectors * BDRV_SECTOR_SIZE);
549             bdrv_dirty_bitmap_unlock(bmds->dirty_bitmap);
551             blk = g_new(BlkMigBlock, 1);
552             blk->buf = g_malloc(BLK_MIG_BLOCK_SIZE);
553             blk->bmds = bmds;
554             blk->sector = sector;
555             blk->nr_sectors = nr_sectors;
557             if (is_async) {
558                 qemu_iovec_init_buf(&blk->qiov, blk->buf,
559                                     nr_sectors * BDRV_SECTOR_SIZE);
561                 blk->aiocb = blk_aio_preadv(bmds->blk,
562                                             sector * BDRV_SECTOR_SIZE,
563                                             &blk->qiov, 0, blk_mig_read_cb,
564                                             blk);
566                 blk_mig_lock();
567                 block_mig_state.submitted++;
568                 bmds_set_aio_inflight(bmds, sector, nr_sectors, 1);
569                 blk_mig_unlock();
570             } else {
571                 ret = blk_pread(bmds->blk, sector * BDRV_SECTOR_SIZE, blk->buf,
572                                 nr_sectors * BDRV_SECTOR_SIZE);
573                 if (ret < 0) {
574                     goto error;
575                 }
576                 blk_send(f, blk);
578                 g_free(blk->buf);
579                 g_free(blk);
580             }
582             sector += nr_sectors;
583             bmds->cur_dirty = sector;
584             break;
585         }
587         bdrv_dirty_bitmap_unlock(bmds->dirty_bitmap);
588         sector += BDRV_SECTORS_PER_DIRTY_CHUNK;
589         bmds->cur_dirty = sector;
590     }
592     return (bmds->cur_dirty >= bmds->total_sectors);
594 error:
595     trace_migration_block_save_device_dirty(sector);
596     g_free(blk->buf);
597     g_free(blk);
598     return ret;
601 /* Called with iothread lock taken.
603  * return value:
604  * 0: too much data for max_downtime
605  * 1: few enough data for max_downtime
607 static int blk_mig_save_dirty_block(QEMUFile *f, int is_async)
609     BlkMigDevState *bmds;
610     int ret = 1;
612     QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
613         aio_context_acquire(blk_get_aio_context(bmds->blk));
614         ret = mig_save_device_dirty(f, bmds, is_async);
615         aio_context_release(blk_get_aio_context(bmds->blk));
616         if (ret <= 0) {
617             break;
618         }
619     }
621     return ret;
624 /* Called with no locks taken.  */
626 static int flush_blks(QEMUFile *f)
628     BlkMigBlock *blk;
629     int ret = 0;
631     trace_migration_block_flush_blks("Enter", block_mig_state.submitted,
632                                      block_mig_state.read_done,
633                                      block_mig_state.transferred);
635     blk_mig_lock();
636     while ((blk = QSIMPLEQ_FIRST(&block_mig_state.blk_list)) != NULL) {
637         if (qemu_file_rate_limit(f)) {
638             break;
639         }
640         if (blk->ret < 0) {
641             ret = blk->ret;
642             break;
643         }
645         QSIMPLEQ_REMOVE_HEAD(&block_mig_state.blk_list, entry);
646         blk_mig_unlock();
647         blk_send(f, blk);
648         blk_mig_lock();
650         g_free(blk->buf);
651         g_free(blk);
653         block_mig_state.read_done--;
654         block_mig_state.transferred++;
655         assert(block_mig_state.read_done >= 0);
656     }
657     blk_mig_unlock();
659     trace_migration_block_flush_blks("Exit", block_mig_state.submitted,
660                                      block_mig_state.read_done,
661                                      block_mig_state.transferred);
662     return ret;
665 /* Called with iothread lock taken.  */
667 static int64_t get_remaining_dirty(void)
669     BlkMigDevState *bmds;
670     int64_t dirty = 0;
672     QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
673         aio_context_acquire(blk_get_aio_context(bmds->blk));
674         dirty += bdrv_get_dirty_count(bmds->dirty_bitmap);
675         aio_context_release(blk_get_aio_context(bmds->blk));
676     }
678     return dirty;
683 /* Called with iothread lock taken.  */
684 static void block_migration_cleanup_bmds(void)
686     BlkMigDevState *bmds;
687     AioContext *ctx;
689     unset_dirty_tracking();
691     while ((bmds = QSIMPLEQ_FIRST(&block_mig_state.bmds_list)) != NULL) {
692         QSIMPLEQ_REMOVE_HEAD(&block_mig_state.bmds_list, entry);
693         bdrv_op_unblock_all(blk_bs(bmds->blk), bmds->blocker);
694         error_free(bmds->blocker);
696         /* Save ctx, because bmds->blk can disappear during blk_unref.  */
697         ctx = blk_get_aio_context(bmds->blk);
698         aio_context_acquire(ctx);
699         blk_unref(bmds->blk);
700         aio_context_release(ctx);
702         g_free(bmds->blk_name);
703         g_free(bmds->aio_bitmap);
704         g_free(bmds);
705     }
708 /* Called with iothread lock taken.  */
709 static void block_migration_cleanup(void *opaque)
711     BlkMigBlock *blk;
713     bdrv_drain_all();
715     block_migration_cleanup_bmds();
717     blk_mig_lock();
718     while ((blk = QSIMPLEQ_FIRST(&block_mig_state.blk_list)) != NULL) {
719         QSIMPLEQ_REMOVE_HEAD(&block_mig_state.blk_list, entry);
720         g_free(blk->buf);
721         g_free(blk);
722     }
723     blk_mig_unlock();
726 static int block_save_setup(QEMUFile *f, void *opaque)
728     int ret;
730     trace_migration_block_save("setup", block_mig_state.submitted,
731                                block_mig_state.transferred);
733     qemu_mutex_lock_iothread();
734     ret = init_blk_migration(f);
735     if (ret < 0) {
736         qemu_mutex_unlock_iothread();
737         return ret;
738     }
740     /* start track dirty blocks */
741     ret = set_dirty_tracking();
743     qemu_mutex_unlock_iothread();
745     if (ret) {
746         return ret;
747     }
749     ret = flush_blks(f);
750     blk_mig_reset_dirty_cursor();
751     qemu_put_be64(f, BLK_MIG_FLAG_EOS);
753     return ret;
756 static int block_save_iterate(QEMUFile *f, void *opaque)
758     int ret;
759     int64_t last_ftell = qemu_ftell(f);
760     int64_t delta_ftell;
762     trace_migration_block_save("iterate", block_mig_state.submitted,
763                                block_mig_state.transferred);
765     ret = flush_blks(f);
766     if (ret) {
767         return ret;
768     }
770     blk_mig_reset_dirty_cursor();
772     /* control the rate of transfer */
773     blk_mig_lock();
774     while (block_mig_state.read_done * BLK_MIG_BLOCK_SIZE <
775            qemu_file_get_rate_limit(f) &&
776            block_mig_state.submitted < MAX_PARALLEL_IO &&
777            (block_mig_state.submitted + block_mig_state.read_done) <
778            MAX_IO_BUFFERS) {
779         blk_mig_unlock();
780         if (block_mig_state.bulk_completed == 0) {
781             /* first finish the bulk phase */
782             if (blk_mig_save_bulked_block(f) == 0) {
783                 /* finished saving bulk on all devices */
784                 block_mig_state.bulk_completed = 1;
785             }
786             ret = 0;
787         } else {
788             /* Always called with iothread lock taken for
789              * simplicity, block_save_complete also calls it.
790              */
791             qemu_mutex_lock_iothread();
792             ret = blk_mig_save_dirty_block(f, 1);
793             qemu_mutex_unlock_iothread();
794         }
795         if (ret < 0) {
796             return ret;
797         }
798         blk_mig_lock();
799         if (ret != 0) {
800             /* no more dirty blocks */
801             break;
802         }
803     }
804     blk_mig_unlock();
806     ret = flush_blks(f);
807     if (ret) {
808         return ret;
809     }
811     qemu_put_be64(f, BLK_MIG_FLAG_EOS);
812     delta_ftell = qemu_ftell(f) - last_ftell;
813     if (delta_ftell > 0) {
814         return 1;
815     } else if (delta_ftell < 0) {
816         return -1;
817     } else {
818         return 0;
819     }
822 /* Called with iothread lock taken.  */
824 static int block_save_complete(QEMUFile *f, void *opaque)
826     int ret;
828     trace_migration_block_save("complete", block_mig_state.submitted,
829                                block_mig_state.transferred);
831     ret = flush_blks(f);
832     if (ret) {
833         return ret;
834     }
836     blk_mig_reset_dirty_cursor();
838     /* we know for sure that save bulk is completed and
839        all async read completed */
840     blk_mig_lock();
841     assert(block_mig_state.submitted == 0);
842     blk_mig_unlock();
844     do {
845         ret = blk_mig_save_dirty_block(f, 0);
846         if (ret < 0) {
847             return ret;
848         }
849     } while (ret == 0);
851     /* report completion */
852     qemu_put_be64(f, (100 << BDRV_SECTOR_BITS) | BLK_MIG_FLAG_PROGRESS);
854     trace_migration_block_save_complete();
856     qemu_put_be64(f, BLK_MIG_FLAG_EOS);
858     /* Make sure that our BlockBackends are gone, so that the block driver
859      * nodes can be inactivated. */
860     block_migration_cleanup_bmds();
862     return 0;
865 static void block_save_pending(QEMUFile *f, void *opaque, uint64_t max_size,
866                                uint64_t *res_precopy_only,
867                                uint64_t *res_compatible,
868                                uint64_t *res_postcopy_only)
870     /* Estimate pending number of bytes to send */
871     uint64_t pending;
873     qemu_mutex_lock_iothread();
874     pending = get_remaining_dirty();
875     qemu_mutex_unlock_iothread();
877     blk_mig_lock();
878     pending += block_mig_state.submitted * BLK_MIG_BLOCK_SIZE +
879                block_mig_state.read_done * BLK_MIG_BLOCK_SIZE;
880     blk_mig_unlock();
882     /* Report at least one block pending during bulk phase */
883     if (pending <= max_size && !block_mig_state.bulk_completed) {
884         pending = max_size + BLK_MIG_BLOCK_SIZE;
885     }
887     trace_migration_block_save_pending(pending);
888     /* We don't do postcopy */
889     *res_precopy_only += pending;
892 static int block_load(QEMUFile *f, void *opaque, int version_id)
894     static int banner_printed;
895     int len, flags;
896     char device_name[256];
897     int64_t addr;
898     BlockBackend *blk, *blk_prev = NULL;
899     Error *local_err = NULL;
900     uint8_t *buf;
901     int64_t total_sectors = 0;
902     int nr_sectors;
903     int ret;
904     BlockDriverInfo bdi;
905     int cluster_size = BLK_MIG_BLOCK_SIZE;
907     do {
908         addr = qemu_get_be64(f);
910         flags = addr & (BDRV_SECTOR_SIZE - 1);
911         addr >>= BDRV_SECTOR_BITS;
913         if (flags & BLK_MIG_FLAG_DEVICE_BLOCK) {
914             /* get device name */
915             len = qemu_get_byte(f);
916             qemu_get_buffer(f, (uint8_t *)device_name, len);
917             device_name[len] = '\0';
919             blk = blk_by_name(device_name);
920             if (!blk) {
921                 fprintf(stderr, "Error unknown block device %s\n",
922                         device_name);
923                 return -EINVAL;
924             }
926             if (blk != blk_prev) {
927                 blk_prev = blk;
928                 total_sectors = blk_nb_sectors(blk);
929                 if (total_sectors <= 0) {
930                     error_report("Error getting length of block device %s",
931                                  device_name);
932                     return -EINVAL;
933                 }
935                 blk_invalidate_cache(blk, &local_err);
936                 if (local_err) {
937                     error_report_err(local_err);
938                     return -EINVAL;
939                 }
941                 ret = bdrv_get_info(blk_bs(blk), &bdi);
942                 if (ret == 0 && bdi.cluster_size > 0 &&
943                     bdi.cluster_size <= BLK_MIG_BLOCK_SIZE &&
944                     BLK_MIG_BLOCK_SIZE % bdi.cluster_size == 0) {
945                     cluster_size = bdi.cluster_size;
946                 } else {
947                     cluster_size = BLK_MIG_BLOCK_SIZE;
948                 }
949             }
951             if (total_sectors - addr < BDRV_SECTORS_PER_DIRTY_CHUNK) {
952                 nr_sectors = total_sectors - addr;
953             } else {
954                 nr_sectors = BDRV_SECTORS_PER_DIRTY_CHUNK;
955             }
957             if (flags & BLK_MIG_FLAG_ZERO_BLOCK) {
958                 ret = blk_pwrite_zeroes(blk, addr * BDRV_SECTOR_SIZE,
959                                         nr_sectors * BDRV_SECTOR_SIZE,
960                                         BDRV_REQ_MAY_UNMAP);
961             } else {
962                 int i;
963                 int64_t cur_addr;
964                 uint8_t *cur_buf;
966                 buf = g_malloc(BLK_MIG_BLOCK_SIZE);
967                 qemu_get_buffer(f, buf, BLK_MIG_BLOCK_SIZE);
968                 for (i = 0; i < BLK_MIG_BLOCK_SIZE / cluster_size; i++) {
969                     cur_addr = addr * BDRV_SECTOR_SIZE + i * cluster_size;
970                     cur_buf = buf + i * cluster_size;
972                     if ((!block_mig_state.zero_blocks ||
973                         cluster_size < BLK_MIG_BLOCK_SIZE) &&
974                         buffer_is_zero(cur_buf, cluster_size)) {
975                         ret = blk_pwrite_zeroes(blk, cur_addr,
976                                                 cluster_size,
977                                                 BDRV_REQ_MAY_UNMAP);
978                     } else {
979                         ret = blk_pwrite(blk, cur_addr, cur_buf,
980                                          cluster_size, 0);
981                     }
982                     if (ret < 0) {
983                         break;
984                     }
985                 }
986                 g_free(buf);
987             }
989             if (ret < 0) {
990                 return ret;
991             }
992         } else if (flags & BLK_MIG_FLAG_PROGRESS) {
993             if (!banner_printed) {
994                 printf("Receiving block device images\n");
995                 banner_printed = 1;
996             }
997             printf("Completed %d %%%c", (int)addr,
998                    (addr == 100) ? '\n' : '\r');
999             fflush(stdout);
1000         } else if (!(flags & BLK_MIG_FLAG_EOS)) {
1001             fprintf(stderr, "Unknown block migration flags: 0x%x\n", flags);
1002             return -EINVAL;
1003         }
1004         ret = qemu_file_get_error(f);
1005         if (ret != 0) {
1006             return ret;
1007         }
1008     } while (!(flags & BLK_MIG_FLAG_EOS));
1010     return 0;
1013 static bool block_is_active(void *opaque)
1015     return migrate_use_block();
1018 static SaveVMHandlers savevm_block_handlers = {
1019     .save_setup = block_save_setup,
1020     .save_live_iterate = block_save_iterate,
1021     .save_live_complete_precopy = block_save_complete,
1022     .save_live_pending = block_save_pending,
1023     .load_state = block_load,
1024     .save_cleanup = block_migration_cleanup,
1025     .is_active = block_is_active,
1028 void blk_mig_init(void)
1030     QSIMPLEQ_INIT(&block_mig_state.bmds_list);
1031     QSIMPLEQ_INIT(&block_mig_state.blk_list);
1032     qemu_mutex_init(&block_mig_state.lock);
1034     register_savevm_live("block", 0, 1, &savevm_block_handlers,
1035                          &block_mig_state);