hw/arm/virt-acpi-build: don't save VirtGuestInfo on AcpiBuildState
[qemu.git] / migration / block.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/osdep.h"
17 #include "qapi/error.h"
18 #include "qemu-common.h"
19 #include "block/block.h"
20 #include "qemu/error-report.h"
21 #include "qemu/main-loop.h"
22 #include "hw/hw.h"
23 #include "qemu/cutils.h"
24 #include "qemu/queue.h"
25 #include "qemu/timer.h"
26 #include "migration/block.h"
27 #include "migration/migration.h"
28 #include "sysemu/blockdev.h"
29 #include "sysemu/block-backend.h"
30
31 #define BLOCK_SIZE (1 << 20)
32 #define BDRV_SECTORS_PER_DIRTY_CHUNK (BLOCK_SIZE >> BDRV_SECTOR_BITS)
33
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
38
39 #define MAX_IS_ALLOCATED_SEARCH 65536
40
41 #define MAX_INFLIGHT_IO 512
42
43 //#define DEBUG_BLK_MIGRATION
44
45 #ifdef DEBUG_BLK_MIGRATION
46 #define DPRINTF(fmt, ...) \
47 do { printf("blk_migration: " fmt, ## __VA_ARGS__); } while (0)
48 #else
49 #define DPRINTF(fmt, ...) \
50 do { } while (0)
51 #endif
52
53 typedef struct BlkMigDevState {
54 /* Written during setup phase. Can be read without a lock. */
55 BlockBackend *blk;
56 char *blk_name;
57 int shared_base;
58 int64_t total_sectors;
59 QSIMPLEQ_ENTRY(BlkMigDevState) entry;
60 Error *blocker;
61
62 /* Only used by migration thread. Does not need a lock. */
63 int bulk_completed;
64 int64_t cur_sector;
65 int64_t cur_dirty;
66
67 /* Data in the aio_bitmap is protected by block migration lock.
68 * Allocation and free happen during setup and cleanup respectively.
69 */
70 unsigned long *aio_bitmap;
71
72 /* Protected by block migration lock. */
73 int64_t completed_sectors;
74
75 /* During migration this is protected by iothread lock / AioContext.
76 * Allocation and free happen during setup and cleanup respectively.
77 */
78 BdrvDirtyBitmap *dirty_bitmap;
79 } BlkMigDevState;
80
81 typedef struct BlkMigBlock {
82 /* Only used by migration thread. */
83 uint8_t *buf;
84 BlkMigDevState *bmds;
85 int64_t sector;
86 int nr_sectors;
87 struct iovec iov;
88 QEMUIOVector qiov;
89 BlockAIOCB *aiocb;
90
91 /* Protected by block migration lock. */
92 int ret;
93 QSIMPLEQ_ENTRY(BlkMigBlock) entry;
94 } BlkMigBlock;
95
96 typedef struct BlkMigState {
97 /* Written during setup phase. Can be read without a lock. */
98 int blk_enable;
99 int shared_base;
100 QSIMPLEQ_HEAD(bmds_list, BlkMigDevState) bmds_list;
101 int64_t total_sector_sum;
102 bool zero_blocks;
103
104 /* Protected by lock. */
105 QSIMPLEQ_HEAD(blk_list, BlkMigBlock) blk_list;
106 int submitted;
107 int read_done;
108
109 /* Only used by migration thread. Does not need a lock. */
110 int transferred;
111 int prev_progress;
112 int bulk_completed;
113
114 /* Lock must be taken _inside_ the iothread lock and any AioContexts. */
115 QemuMutex lock;
116 } BlkMigState;
117
118 static BlkMigState block_mig_state;
119
120 static void blk_mig_lock(void)
121 {
122 qemu_mutex_lock(&block_mig_state.lock);
123 }
124
125 static void blk_mig_unlock(void)
126 {
127 qemu_mutex_unlock(&block_mig_state.lock);
128 }
129
130 /* Must run outside of the iothread lock during the bulk phase,
131 * or the VM will stall.
132 */
133
134 static void blk_send(QEMUFile *f, BlkMigBlock * blk)
135 {
136 int len;
137 uint64_t flags = BLK_MIG_FLAG_DEVICE_BLOCK;
138
139 if (block_mig_state.zero_blocks &&
140 buffer_is_zero(blk->buf, BLOCK_SIZE)) {
141 flags |= BLK_MIG_FLAG_ZERO_BLOCK;
142 }
143
144 /* sector number and flags */
145 qemu_put_be64(f, (blk->sector << BDRV_SECTOR_BITS)
146 | flags);
147
148 /* device name */
149 len = strlen(blk->bmds->blk_name);
150 qemu_put_byte(f, len);
151 qemu_put_buffer(f, (uint8_t *) blk->bmds->blk_name, len);
152
153 /* if a block is zero we need to flush here since the network
154 * bandwidth is now a lot higher than the storage device bandwidth.
155 * thus if we queue zero blocks we slow down the migration */
156 if (flags & BLK_MIG_FLAG_ZERO_BLOCK) {
157 qemu_fflush(f);
158 return;
159 }
160
161 qemu_put_buffer(f, blk->buf, BLOCK_SIZE);
162 }
163
164 int blk_mig_active(void)
165 {
166 return !QSIMPLEQ_EMPTY(&block_mig_state.bmds_list);
167 }
168
169 uint64_t blk_mig_bytes_transferred(void)
170 {
171 BlkMigDevState *bmds;
172 uint64_t sum = 0;
173
174 blk_mig_lock();
175 QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
176 sum += bmds->completed_sectors;
177 }
178 blk_mig_unlock();
179 return sum << BDRV_SECTOR_BITS;
180 }
181
182 uint64_t blk_mig_bytes_remaining(void)
183 {
184 return blk_mig_bytes_total() - blk_mig_bytes_transferred();
185 }
186
187 uint64_t blk_mig_bytes_total(void)
188 {
189 BlkMigDevState *bmds;
190 uint64_t sum = 0;
191
192 QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
193 sum += bmds->total_sectors;
194 }
195 return sum << BDRV_SECTOR_BITS;
196 }
197
198
199 /* Called with migration lock held. */
200
201 static int bmds_aio_inflight(BlkMigDevState *bmds, int64_t sector)
202 {
203 int64_t chunk = sector / (int64_t)BDRV_SECTORS_PER_DIRTY_CHUNK;
204
205 if (sector < blk_nb_sectors(bmds->blk)) {
206 return !!(bmds->aio_bitmap[chunk / (sizeof(unsigned long) * 8)] &
207 (1UL << (chunk % (sizeof(unsigned long) * 8))));
208 } else {
209 return 0;
210 }
211 }
212
213 /* Called with migration lock held. */
214
215 static void bmds_set_aio_inflight(BlkMigDevState *bmds, int64_t sector_num,
216 int nb_sectors, int set)
217 {
218 int64_t start, end;
219 unsigned long val, idx, bit;
220
221 start = sector_num / BDRV_SECTORS_PER_DIRTY_CHUNK;
222 end = (sector_num + nb_sectors - 1) / BDRV_SECTORS_PER_DIRTY_CHUNK;
223
224 for (; start <= end; start++) {
225 idx = start / (sizeof(unsigned long) * 8);
226 bit = start % (sizeof(unsigned long) * 8);
227 val = bmds->aio_bitmap[idx];
228 if (set) {
229 val |= 1UL << bit;
230 } else {
231 val &= ~(1UL << bit);
232 }
233 bmds->aio_bitmap[idx] = val;
234 }
235 }
236
237 static void alloc_aio_bitmap(BlkMigDevState *bmds)
238 {
239 BlockBackend *bb = bmds->blk;
240 int64_t bitmap_size;
241
242 bitmap_size = blk_nb_sectors(bb) + BDRV_SECTORS_PER_DIRTY_CHUNK * 8 - 1;
243 bitmap_size /= BDRV_SECTORS_PER_DIRTY_CHUNK * 8;
244
245 bmds->aio_bitmap = g_malloc0(bitmap_size);
246 }
247
248 /* Never hold migration lock when yielding to the main loop! */
249
250 static void blk_mig_read_cb(void *opaque, int ret)
251 {
252 BlkMigBlock *blk = opaque;
253
254 blk_mig_lock();
255 blk->ret = ret;
256
257 QSIMPLEQ_INSERT_TAIL(&block_mig_state.blk_list, blk, entry);
258 bmds_set_aio_inflight(blk->bmds, blk->sector, blk->nr_sectors, 0);
259
260 block_mig_state.submitted--;
261 block_mig_state.read_done++;
262 assert(block_mig_state.submitted >= 0);
263 blk_mig_unlock();
264 }
265
266 /* Called with no lock taken. */
267
268 static int mig_save_device_bulk(QEMUFile *f, BlkMigDevState *bmds)
269 {
270 int64_t total_sectors = bmds->total_sectors;
271 int64_t cur_sector = bmds->cur_sector;
272 BlockBackend *bb = bmds->blk;
273 BlkMigBlock *blk;
274 int nr_sectors;
275
276 if (bmds->shared_base) {
277 qemu_mutex_lock_iothread();
278 aio_context_acquire(blk_get_aio_context(bb));
279 while (cur_sector < total_sectors &&
280 !bdrv_is_allocated(blk_bs(bb), cur_sector,
281 MAX_IS_ALLOCATED_SEARCH, &nr_sectors)) {
282 cur_sector += nr_sectors;
283 }
284 aio_context_release(blk_get_aio_context(bb));
285 qemu_mutex_unlock_iothread();
286 }
287
288 if (cur_sector >= total_sectors) {
289 bmds->cur_sector = bmds->completed_sectors = total_sectors;
290 return 1;
291 }
292
293 bmds->completed_sectors = cur_sector;
294
295 cur_sector &= ~((int64_t)BDRV_SECTORS_PER_DIRTY_CHUNK - 1);
296
297 /* we are going to transfer a full block even if it is not allocated */
298 nr_sectors = BDRV_SECTORS_PER_DIRTY_CHUNK;
299
300 if (total_sectors - cur_sector < BDRV_SECTORS_PER_DIRTY_CHUNK) {
301 nr_sectors = total_sectors - cur_sector;
302 }
303
304 blk = g_new(BlkMigBlock, 1);
305 blk->buf = g_malloc(BLOCK_SIZE);
306 blk->bmds = bmds;
307 blk->sector = cur_sector;
308 blk->nr_sectors = nr_sectors;
309
310 blk->iov.iov_base = blk->buf;
311 blk->iov.iov_len = nr_sectors * BDRV_SECTOR_SIZE;
312 qemu_iovec_init_external(&blk->qiov, &blk->iov, 1);
313
314 blk_mig_lock();
315 block_mig_state.submitted++;
316 blk_mig_unlock();
317
318 /* We do not know if bs is under the main thread (and thus does
319 * not acquire the AioContext when doing AIO) or rather under
320 * dataplane. Thus acquire both the iothread mutex and the
321 * AioContext.
322 *
323 * This is ugly and will disappear when we make bdrv_* thread-safe,
324 * without the need to acquire the AioContext.
325 */
326 qemu_mutex_lock_iothread();
327 aio_context_acquire(blk_get_aio_context(bmds->blk));
328 blk->aiocb = blk_aio_preadv(bb, cur_sector * BDRV_SECTOR_SIZE, &blk->qiov,
329 0, blk_mig_read_cb, blk);
330
331 bdrv_reset_dirty_bitmap(bmds->dirty_bitmap, cur_sector, nr_sectors);
332 aio_context_release(blk_get_aio_context(bmds->blk));
333 qemu_mutex_unlock_iothread();
334
335 bmds->cur_sector = cur_sector + nr_sectors;
336 return (bmds->cur_sector >= total_sectors);
337 }
338
339 /* Called with iothread lock taken. */
340
341 static int set_dirty_tracking(void)
342 {
343 BlkMigDevState *bmds;
344 int ret;
345
346 QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
347 aio_context_acquire(blk_get_aio_context(bmds->blk));
348 bmds->dirty_bitmap = bdrv_create_dirty_bitmap(blk_bs(bmds->blk),
349 BLOCK_SIZE, NULL, NULL);
350 aio_context_release(blk_get_aio_context(bmds->blk));
351 if (!bmds->dirty_bitmap) {
352 ret = -errno;
353 goto fail;
354 }
355 }
356 return 0;
357
358 fail:
359 QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
360 if (bmds->dirty_bitmap) {
361 aio_context_acquire(blk_get_aio_context(bmds->blk));
362 bdrv_release_dirty_bitmap(blk_bs(bmds->blk), bmds->dirty_bitmap);
363 aio_context_release(blk_get_aio_context(bmds->blk));
364 }
365 }
366 return ret;
367 }
368
369 /* Called with iothread lock taken. */
370
371 static void unset_dirty_tracking(void)
372 {
373 BlkMigDevState *bmds;
374
375 QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
376 aio_context_acquire(blk_get_aio_context(bmds->blk));
377 bdrv_release_dirty_bitmap(blk_bs(bmds->blk), bmds->dirty_bitmap);
378 aio_context_release(blk_get_aio_context(bmds->blk));
379 }
380 }
381
382 static void init_blk_migration(QEMUFile *f)
383 {
384 BlockDriverState *bs;
385 BlkMigDevState *bmds;
386 int64_t sectors;
387 BdrvNextIterator it;
388 int i, num_bs = 0;
389 struct {
390 BlkMigDevState *bmds;
391 BlockDriverState *bs;
392 } *bmds_bs;
393
394 block_mig_state.submitted = 0;
395 block_mig_state.read_done = 0;
396 block_mig_state.transferred = 0;
397 block_mig_state.total_sector_sum = 0;
398 block_mig_state.prev_progress = -1;
399 block_mig_state.bulk_completed = 0;
400 block_mig_state.zero_blocks = migrate_zero_blocks();
401
402 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
403 num_bs++;
404 }
405 bmds_bs = g_malloc0(num_bs * sizeof(*bmds_bs));
406
407 for (i = 0, bs = bdrv_first(&it); bs; bs = bdrv_next(&it), i++) {
408 if (bdrv_is_read_only(bs)) {
409 continue;
410 }
411
412 sectors = bdrv_nb_sectors(bs);
413 if (sectors <= 0) {
414 goto out;
415 }
416
417 bmds = g_new0(BlkMigDevState, 1);
418 bmds->blk = blk_new();
419 bmds->blk_name = g_strdup(bdrv_get_device_name(bs));
420 bmds->bulk_completed = 0;
421 bmds->total_sectors = sectors;
422 bmds->completed_sectors = 0;
423 bmds->shared_base = block_mig_state.shared_base;
424
425 assert(i < num_bs);
426 bmds_bs[i].bmds = bmds;
427 bmds_bs[i].bs = bs;
428
429 block_mig_state.total_sector_sum += sectors;
430
431 if (bmds->shared_base) {
432 DPRINTF("Start migration for %s with shared base image\n",
433 bdrv_get_device_name(bs));
434 } else {
435 DPRINTF("Start full migration for %s\n", bdrv_get_device_name(bs));
436 }
437
438 QSIMPLEQ_INSERT_TAIL(&block_mig_state.bmds_list, bmds, entry);
439 }
440
441 /* Can only insert new BDSes now because doing so while iterating block
442 * devices may end up in a deadlock (iterating the new BDSes, too). */
443 for (i = 0; i < num_bs; i++) {
444 BlkMigDevState *bmds = bmds_bs[i].bmds;
445 BlockDriverState *bs = bmds_bs[i].bs;
446
447 if (bmds) {
448 blk_insert_bs(bmds->blk, bs);
449
450 alloc_aio_bitmap(bmds);
451 error_setg(&bmds->blocker, "block device is in use by migration");
452 bdrv_op_block_all(bs, bmds->blocker);
453 }
454 }
455
456 out:
457 g_free(bmds_bs);
458 }
459
460 /* Called with no lock taken. */
461
462 static int blk_mig_save_bulked_block(QEMUFile *f)
463 {
464 int64_t completed_sector_sum = 0;
465 BlkMigDevState *bmds;
466 int progress;
467 int ret = 0;
468
469 QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
470 if (bmds->bulk_completed == 0) {
471 if (mig_save_device_bulk(f, bmds) == 1) {
472 /* completed bulk section for this device */
473 bmds->bulk_completed = 1;
474 }
475 completed_sector_sum += bmds->completed_sectors;
476 ret = 1;
477 break;
478 } else {
479 completed_sector_sum += bmds->completed_sectors;
480 }
481 }
482
483 if (block_mig_state.total_sector_sum != 0) {
484 progress = completed_sector_sum * 100 /
485 block_mig_state.total_sector_sum;
486 } else {
487 progress = 100;
488 }
489 if (progress != block_mig_state.prev_progress) {
490 block_mig_state.prev_progress = progress;
491 qemu_put_be64(f, (progress << BDRV_SECTOR_BITS)
492 | BLK_MIG_FLAG_PROGRESS);
493 DPRINTF("Completed %d %%\r", progress);
494 }
495
496 return ret;
497 }
498
499 static void blk_mig_reset_dirty_cursor(void)
500 {
501 BlkMigDevState *bmds;
502
503 QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
504 bmds->cur_dirty = 0;
505 }
506 }
507
508 /* Called with iothread lock and AioContext taken. */
509
510 static int mig_save_device_dirty(QEMUFile *f, BlkMigDevState *bmds,
511 int is_async)
512 {
513 BlkMigBlock *blk;
514 BlockDriverState *bs = blk_bs(bmds->blk);
515 int64_t total_sectors = bmds->total_sectors;
516 int64_t sector;
517 int nr_sectors;
518 int ret = -EIO;
519
520 for (sector = bmds->cur_dirty; sector < bmds->total_sectors;) {
521 blk_mig_lock();
522 if (bmds_aio_inflight(bmds, sector)) {
523 blk_mig_unlock();
524 blk_drain(bmds->blk);
525 } else {
526 blk_mig_unlock();
527 }
528 if (bdrv_get_dirty(bs, bmds->dirty_bitmap, sector)) {
529
530 if (total_sectors - sector < BDRV_SECTORS_PER_DIRTY_CHUNK) {
531 nr_sectors = total_sectors - sector;
532 } else {
533 nr_sectors = BDRV_SECTORS_PER_DIRTY_CHUNK;
534 }
535 blk = g_new(BlkMigBlock, 1);
536 blk->buf = g_malloc(BLOCK_SIZE);
537 blk->bmds = bmds;
538 blk->sector = sector;
539 blk->nr_sectors = nr_sectors;
540
541 if (is_async) {
542 blk->iov.iov_base = blk->buf;
543 blk->iov.iov_len = nr_sectors * BDRV_SECTOR_SIZE;
544 qemu_iovec_init_external(&blk->qiov, &blk->iov, 1);
545
546 blk->aiocb = blk_aio_preadv(bmds->blk,
547 sector * BDRV_SECTOR_SIZE,
548 &blk->qiov, 0, blk_mig_read_cb,
549 blk);
550
551 blk_mig_lock();
552 block_mig_state.submitted++;
553 bmds_set_aio_inflight(bmds, sector, nr_sectors, 1);
554 blk_mig_unlock();
555 } else {
556 ret = blk_pread(bmds->blk, sector * BDRV_SECTOR_SIZE, blk->buf,
557 nr_sectors * BDRV_SECTOR_SIZE);
558 if (ret < 0) {
559 goto error;
560 }
561 blk_send(f, blk);
562
563 g_free(blk->buf);
564 g_free(blk);
565 }
566
567 bdrv_reset_dirty_bitmap(bmds->dirty_bitmap, sector, nr_sectors);
568 break;
569 }
570 sector += BDRV_SECTORS_PER_DIRTY_CHUNK;
571 bmds->cur_dirty = sector;
572 }
573
574 return (bmds->cur_dirty >= bmds->total_sectors);
575
576 error:
577 DPRINTF("Error reading sector %" PRId64 "\n", sector);
578 g_free(blk->buf);
579 g_free(blk);
580 return ret;
581 }
582
583 /* Called with iothread lock taken.
584 *
585 * return value:
586 * 0: too much data for max_downtime
587 * 1: few enough data for max_downtime
588 */
589 static int blk_mig_save_dirty_block(QEMUFile *f, int is_async)
590 {
591 BlkMigDevState *bmds;
592 int ret = 1;
593
594 QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
595 aio_context_acquire(blk_get_aio_context(bmds->blk));
596 ret = mig_save_device_dirty(f, bmds, is_async);
597 aio_context_release(blk_get_aio_context(bmds->blk));
598 if (ret <= 0) {
599 break;
600 }
601 }
602
603 return ret;
604 }
605
606 /* Called with no locks taken. */
607
608 static int flush_blks(QEMUFile *f)
609 {
610 BlkMigBlock *blk;
611 int ret = 0;
612
613 DPRINTF("%s Enter submitted %d read_done %d transferred %d\n",
614 __FUNCTION__, block_mig_state.submitted, block_mig_state.read_done,
615 block_mig_state.transferred);
616
617 blk_mig_lock();
618 while ((blk = QSIMPLEQ_FIRST(&block_mig_state.blk_list)) != NULL) {
619 if (qemu_file_rate_limit(f)) {
620 break;
621 }
622 if (blk->ret < 0) {
623 ret = blk->ret;
624 break;
625 }
626
627 QSIMPLEQ_REMOVE_HEAD(&block_mig_state.blk_list, entry);
628 blk_mig_unlock();
629 blk_send(f, blk);
630 blk_mig_lock();
631
632 g_free(blk->buf);
633 g_free(blk);
634
635 block_mig_state.read_done--;
636 block_mig_state.transferred++;
637 assert(block_mig_state.read_done >= 0);
638 }
639 blk_mig_unlock();
640
641 DPRINTF("%s Exit submitted %d read_done %d transferred %d\n", __FUNCTION__,
642 block_mig_state.submitted, block_mig_state.read_done,
643 block_mig_state.transferred);
644 return ret;
645 }
646
647 /* Called with iothread lock taken. */
648
649 static int64_t get_remaining_dirty(void)
650 {
651 BlkMigDevState *bmds;
652 int64_t dirty = 0;
653
654 QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
655 aio_context_acquire(blk_get_aio_context(bmds->blk));
656 dirty += bdrv_get_dirty_count(bmds->dirty_bitmap);
657 aio_context_release(blk_get_aio_context(bmds->blk));
658 }
659
660 return dirty << BDRV_SECTOR_BITS;
661 }
662
663 /* Called with iothread lock taken. */
664
665 static void block_migration_cleanup(void *opaque)
666 {
667 BlkMigDevState *bmds;
668 BlkMigBlock *blk;
669 AioContext *ctx;
670
671 bdrv_drain_all();
672
673 unset_dirty_tracking();
674
675 while ((bmds = QSIMPLEQ_FIRST(&block_mig_state.bmds_list)) != NULL) {
676 QSIMPLEQ_REMOVE_HEAD(&block_mig_state.bmds_list, entry);
677 bdrv_op_unblock_all(blk_bs(bmds->blk), bmds->blocker);
678 error_free(bmds->blocker);
679
680 /* Save ctx, because bmds->blk can disappear during blk_unref. */
681 ctx = blk_get_aio_context(bmds->blk);
682 aio_context_acquire(ctx);
683 blk_unref(bmds->blk);
684 aio_context_release(ctx);
685
686 g_free(bmds->blk_name);
687 g_free(bmds->aio_bitmap);
688 g_free(bmds);
689 }
690
691 blk_mig_lock();
692 while ((blk = QSIMPLEQ_FIRST(&block_mig_state.blk_list)) != NULL) {
693 QSIMPLEQ_REMOVE_HEAD(&block_mig_state.blk_list, entry);
694 g_free(blk->buf);
695 g_free(blk);
696 }
697 blk_mig_unlock();
698 }
699
700 static int block_save_setup(QEMUFile *f, void *opaque)
701 {
702 int ret;
703
704 DPRINTF("Enter save live setup submitted %d transferred %d\n",
705 block_mig_state.submitted, block_mig_state.transferred);
706
707 qemu_mutex_lock_iothread();
708 init_blk_migration(f);
709
710 /* start track dirty blocks */
711 ret = set_dirty_tracking();
712
713 qemu_mutex_unlock_iothread();
714
715 if (ret) {
716 return ret;
717 }
718
719 ret = flush_blks(f);
720 blk_mig_reset_dirty_cursor();
721 qemu_put_be64(f, BLK_MIG_FLAG_EOS);
722
723 return ret;
724 }
725
726 static int block_save_iterate(QEMUFile *f, void *opaque)
727 {
728 int ret;
729 int64_t last_ftell = qemu_ftell(f);
730 int64_t delta_ftell;
731
732 DPRINTF("Enter save live iterate submitted %d transferred %d\n",
733 block_mig_state.submitted, block_mig_state.transferred);
734
735 ret = flush_blks(f);
736 if (ret) {
737 return ret;
738 }
739
740 blk_mig_reset_dirty_cursor();
741
742 /* control the rate of transfer */
743 blk_mig_lock();
744 while ((block_mig_state.submitted +
745 block_mig_state.read_done) * BLOCK_SIZE <
746 qemu_file_get_rate_limit(f) &&
747 (block_mig_state.submitted +
748 block_mig_state.read_done) <
749 MAX_INFLIGHT_IO) {
750 blk_mig_unlock();
751 if (block_mig_state.bulk_completed == 0) {
752 /* first finish the bulk phase */
753 if (blk_mig_save_bulked_block(f) == 0) {
754 /* finished saving bulk on all devices */
755 block_mig_state.bulk_completed = 1;
756 }
757 ret = 0;
758 } else {
759 /* Always called with iothread lock taken for
760 * simplicity, block_save_complete also calls it.
761 */
762 qemu_mutex_lock_iothread();
763 ret = blk_mig_save_dirty_block(f, 1);
764 qemu_mutex_unlock_iothread();
765 }
766 if (ret < 0) {
767 return ret;
768 }
769 blk_mig_lock();
770 if (ret != 0) {
771 /* no more dirty blocks */
772 break;
773 }
774 }
775 blk_mig_unlock();
776
777 ret = flush_blks(f);
778 if (ret) {
779 return ret;
780 }
781
782 qemu_put_be64(f, BLK_MIG_FLAG_EOS);
783 delta_ftell = qemu_ftell(f) - last_ftell;
784 if (delta_ftell > 0) {
785 return 1;
786 } else if (delta_ftell < 0) {
787 return -1;
788 } else {
789 return 0;
790 }
791 }
792
793 /* Called with iothread lock taken. */
794
795 static int block_save_complete(QEMUFile *f, void *opaque)
796 {
797 int ret;
798
799 DPRINTF("Enter save live complete submitted %d transferred %d\n",
800 block_mig_state.submitted, block_mig_state.transferred);
801
802 ret = flush_blks(f);
803 if (ret) {
804 return ret;
805 }
806
807 blk_mig_reset_dirty_cursor();
808
809 /* we know for sure that save bulk is completed and
810 all async read completed */
811 blk_mig_lock();
812 assert(block_mig_state.submitted == 0);
813 blk_mig_unlock();
814
815 do {
816 ret = blk_mig_save_dirty_block(f, 0);
817 if (ret < 0) {
818 return ret;
819 }
820 } while (ret == 0);
821
822 /* report completion */
823 qemu_put_be64(f, (100 << BDRV_SECTOR_BITS) | BLK_MIG_FLAG_PROGRESS);
824
825 DPRINTF("Block migration completed\n");
826
827 qemu_put_be64(f, BLK_MIG_FLAG_EOS);
828
829 return 0;
830 }
831
832 static void block_save_pending(QEMUFile *f, void *opaque, uint64_t max_size,
833 uint64_t *non_postcopiable_pending,
834 uint64_t *postcopiable_pending)
835 {
836 /* Estimate pending number of bytes to send */
837 uint64_t pending;
838
839 qemu_mutex_lock_iothread();
840 pending = get_remaining_dirty();
841 qemu_mutex_unlock_iothread();
842
843 blk_mig_lock();
844 pending += block_mig_state.submitted * BLOCK_SIZE +
845 block_mig_state.read_done * BLOCK_SIZE;
846 blk_mig_unlock();
847
848 /* Report at least one block pending during bulk phase */
849 if (pending <= max_size && !block_mig_state.bulk_completed) {
850 pending = max_size + BLOCK_SIZE;
851 }
852
853 DPRINTF("Enter save live pending %" PRIu64 "\n", pending);
854 /* We don't do postcopy */
855 *non_postcopiable_pending += pending;
856 }
857
858 static int block_load(QEMUFile *f, void *opaque, int version_id)
859 {
860 static int banner_printed;
861 int len, flags;
862 char device_name[256];
863 int64_t addr;
864 BlockBackend *blk, *blk_prev = NULL;;
865 Error *local_err = NULL;
866 uint8_t *buf;
867 int64_t total_sectors = 0;
868 int nr_sectors;
869 int ret;
870
871 do {
872 addr = qemu_get_be64(f);
873
874 flags = addr & ~BDRV_SECTOR_MASK;
875 addr >>= BDRV_SECTOR_BITS;
876
877 if (flags & BLK_MIG_FLAG_DEVICE_BLOCK) {
878 /* get device name */
879 len = qemu_get_byte(f);
880 qemu_get_buffer(f, (uint8_t *)device_name, len);
881 device_name[len] = '\0';
882
883 blk = blk_by_name(device_name);
884 if (!blk) {
885 fprintf(stderr, "Error unknown block device %s\n",
886 device_name);
887 return -EINVAL;
888 }
889
890 if (blk != blk_prev) {
891 blk_prev = blk;
892 total_sectors = blk_nb_sectors(blk);
893 if (total_sectors <= 0) {
894 error_report("Error getting length of block device %s",
895 device_name);
896 return -EINVAL;
897 }
898
899 blk_invalidate_cache(blk, &local_err);
900 if (local_err) {
901 error_report_err(local_err);
902 return -EINVAL;
903 }
904 }
905
906 if (total_sectors - addr < BDRV_SECTORS_PER_DIRTY_CHUNK) {
907 nr_sectors = total_sectors - addr;
908 } else {
909 nr_sectors = BDRV_SECTORS_PER_DIRTY_CHUNK;
910 }
911
912 if (flags & BLK_MIG_FLAG_ZERO_BLOCK) {
913 ret = blk_pwrite_zeroes(blk, addr * BDRV_SECTOR_SIZE,
914 nr_sectors * BDRV_SECTOR_SIZE,
915 BDRV_REQ_MAY_UNMAP);
916 } else {
917 buf = g_malloc(BLOCK_SIZE);
918 qemu_get_buffer(f, buf, BLOCK_SIZE);
919 ret = blk_pwrite(blk, addr * BDRV_SECTOR_SIZE, buf,
920 nr_sectors * BDRV_SECTOR_SIZE, 0);
921 g_free(buf);
922 }
923
924 if (ret < 0) {
925 return ret;
926 }
927 } else if (flags & BLK_MIG_FLAG_PROGRESS) {
928 if (!banner_printed) {
929 printf("Receiving block device images\n");
930 banner_printed = 1;
931 }
932 printf("Completed %d %%%c", (int)addr,
933 (addr == 100) ? '\n' : '\r');
934 fflush(stdout);
935 } else if (!(flags & BLK_MIG_FLAG_EOS)) {
936 fprintf(stderr, "Unknown block migration flags: %#x\n", flags);
937 return -EINVAL;
938 }
939 ret = qemu_file_get_error(f);
940 if (ret != 0) {
941 return ret;
942 }
943 } while (!(flags & BLK_MIG_FLAG_EOS));
944
945 return 0;
946 }
947
948 static void block_set_params(const MigrationParams *params, void *opaque)
949 {
950 block_mig_state.blk_enable = params->blk;
951 block_mig_state.shared_base = params->shared;
952
953 /* shared base means that blk_enable = 1 */
954 block_mig_state.blk_enable |= params->shared;
955 }
956
957 static bool block_is_active(void *opaque)
958 {
959 return block_mig_state.blk_enable == 1;
960 }
961
962 static SaveVMHandlers savevm_block_handlers = {
963 .set_params = block_set_params,
964 .save_live_setup = block_save_setup,
965 .save_live_iterate = block_save_iterate,
966 .save_live_complete_precopy = block_save_complete,
967 .save_live_pending = block_save_pending,
968 .load_state = block_load,
969 .cleanup = block_migration_cleanup,
970 .is_active = block_is_active,
971 };
972
973 void blk_mig_init(void)
974 {
975 QSIMPLEQ_INIT(&block_mig_state.bmds_list);
976 QSIMPLEQ_INIT(&block_mig_state.blk_list);
977 qemu_mutex_init(&block_mig_state.lock);
978
979 register_savevm_live(NULL, "block", 0, 1, &savevm_block_handlers,
980 &block_mig_state);
981 }