2 * Block dirty bitmap postcopy migration
4 * Copyright IBM, Corp. 2009
5 * Copyright (c) 2016-2017 Virtuozzo International GmbH. All rights reserved.
8 * Liran Schour <lirans@il.ibm.com>
9 * Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
11 * This work is licensed under the terms of the GNU GPL, version 2. See
12 * the COPYING file in the top-level directory.
13 * This file is derived from migration/block.c, so it's author and IBM copyright
14 * are here, although content is quite different.
16 * Contributions after 2012-01-13 are licensed under the terms of the
17 * GNU GPL, version 2 or (at your option) any later version.
21 * Here postcopy migration of dirty bitmaps is realized. Only QMP-addressable
22 * bitmaps are migrated.
24 * Bitmap migration implies creating bitmap with the same name and granularity
25 * in destination QEMU. If the bitmap with the same name (for the same node)
26 * already exists on destination an error will be generated.
28 * format of migration:
30 * # Header (shared for different chunk types)
31 * 1, 2 or 4 bytes: flags (see qemu_{put,put}_flags)
32 * [ 1 byte: node alias size ] \ flags & DEVICE_NAME
33 * [ n bytes: node alias ] /
34 * [ 1 byte: bitmap alias size ] \ flags & BITMAP_NAME
35 * [ n bytes: bitmap alias ] /
37 * # Start of bitmap migration (flags & START)
40 * 1 byte: bitmap flags (corresponds to BdrvDirtyBitmap)
41 * bit 0 - bitmap is enabled
42 * bit 1 - bitmap is persistent
43 * bit 2 - bitmap is autoloading
44 * bits 3-7 - reserved, must be zero
46 * # Complete of bitmap migration (flags & COMPLETE)
49 * # Data chunk of bitmap migration
52 * be32: number of sectors
53 * [ be64: buffer size ] \ ! (flags & ZEROES)
54 * [ n bytes: buffer ] /
56 * The last chunk in stream should contain flags & EOS. The chunk may skip
57 * device and/or bitmap names, assuming them to be the same with the previous
61 #include "qemu/osdep.h"
62 #include "block/block.h"
63 #include "block/block_int.h"
64 #include "block/dirty-bitmap.h"
65 #include "sysemu/block-backend.h"
66 #include "sysemu/runstate.h"
67 #include "qemu/main-loop.h"
68 #include "qemu/error-report.h"
69 #include "migration/misc.h"
70 #include "migration/migration.h"
71 #include "qemu-file.h"
72 #include "migration/vmstate.h"
73 #include "migration/register.h"
74 #include "qemu/hbitmap.h"
75 #include "qemu/cutils.h"
77 #include "qapi/error.h"
78 #include "qapi/qapi-commands-migration.h"
79 #include "qapi/qapi-visit-migration.h"
80 #include "qapi/clone-visitor.h"
84 #define CHUNK_SIZE (1 << 10)
86 /* Flags occupy one, two or four bytes (Big Endian). The size is determined as
88 * in first (most significant) byte bit 8 is clear --> one byte
89 * in first byte bit 8 is set --> two or four bytes, depending on second
91 * | in second byte bit 8 is clear --> two bytes
92 * | in second byte bit 8 is set --> four bytes
94 #define DIRTY_BITMAP_MIG_FLAG_EOS 0x01
95 #define DIRTY_BITMAP_MIG_FLAG_ZEROES 0x02
96 #define DIRTY_BITMAP_MIG_FLAG_BITMAP_NAME 0x04
97 #define DIRTY_BITMAP_MIG_FLAG_DEVICE_NAME 0x08
98 #define DIRTY_BITMAP_MIG_FLAG_START 0x10
99 #define DIRTY_BITMAP_MIG_FLAG_COMPLETE 0x20
100 #define DIRTY_BITMAP_MIG_FLAG_BITS 0x40
102 #define DIRTY_BITMAP_MIG_EXTRA_FLAGS 0x80
104 #define DIRTY_BITMAP_MIG_START_FLAG_ENABLED 0x01
105 #define DIRTY_BITMAP_MIG_START_FLAG_PERSISTENT 0x02
106 /* 0x04 was "AUTOLOAD" flags on older versions, now it is ignored */
107 #define DIRTY_BITMAP_MIG_START_FLAG_RESERVED_MASK 0xf8
109 /* State of one bitmap during save process */
110 typedef struct SaveBitmapState {
111 /* Written during setup phase. */
112 BlockDriverState *bs;
115 BdrvDirtyBitmap *bitmap;
116 uint64_t total_sectors;
117 uint64_t sectors_per_chunk;
118 QSIMPLEQ_ENTRY(SaveBitmapState) entry;
121 /* For bulk phase. */
126 /* State of the dirty bitmap migration (DBM) during save process */
127 typedef struct DBMSaveState {
128 QSIMPLEQ_HEAD(, SaveBitmapState) dbms_list;
133 /* for send_bitmap_bits() */
134 BlockDriverState *prev_bs;
135 BdrvDirtyBitmap *prev_bitmap;
138 typedef struct LoadBitmapState {
139 BlockDriverState *bs;
140 BdrvDirtyBitmap *bitmap;
145 /* State of the dirty bitmap migration (DBM) during load process */
146 typedef struct DBMLoadState {
148 char node_alias[256];
149 char bitmap_alias[256];
150 char bitmap_name[BDRV_BITMAP_MAX_NAME_SIZE + 1];
151 BlockDriverState *bs;
152 BdrvDirtyBitmap *bitmap;
154 bool before_vm_start_handled; /* set in dirty_bitmap_mig_before_vm_start */
155 BitmapMigrationBitmapAlias *bmap_inner;
159 * Incoming migration is cancelled for some reason. That means that we
160 * still should read our chunks from migration stream, to not affect other
161 * migration objects (like RAM), but just ignore them and do not touch any
167 QemuMutex lock; /* protect bitmaps */
170 typedef struct DBMState {
175 static DBMState dbm_state;
177 /* For hash tables that map node/bitmap names to aliases */
178 typedef struct AliasMapInnerNode {
183 static void free_alias_map_inner_node(void *amin_ptr)
185 AliasMapInnerNode *amin = amin_ptr;
187 g_free(amin->string);
188 g_hash_table_unref(amin->subtree);
193 * Construct an alias map based on the given QMP structure.
195 * (Note that we cannot store such maps in the MigrationParameters
196 * object, because that struct is defined by the QAPI schema, which
197 * makes it basically impossible to have dicts with arbitrary keys.
198 * Therefore, we instead have to construct these maps when migration
201 * @bbm is the block_bitmap_mapping from the migration parameters.
203 * If @name_to_alias is true, the returned hash table will map node
204 * and bitmap names to their respective aliases (for outgoing
207 * If @name_to_alias is false, the returned hash table will map node
208 * and bitmap aliases to their respective names (for incoming
211 * The hash table maps node names/aliases to AliasMapInnerNode
212 * objects, whose .string is the respective node alias/name, and whose
213 * .subtree table maps bitmap names/aliases to the respective bitmap
216 static GHashTable *construct_alias_map(const BitmapMigrationNodeAliasList *bbm,
220 GHashTable *alias_map;
221 size_t max_node_name_len = sizeof_field(BlockDriverState, node_name) - 1;
223 alias_map = g_hash_table_new_full(g_str_hash, g_str_equal,
224 g_free, free_alias_map_inner_node);
226 for (; bbm; bbm = bbm->next) {
227 const BitmapMigrationNodeAlias *bmna = bbm->value;
228 const BitmapMigrationBitmapAliasList *bmbal;
229 AliasMapInnerNode *amin;
230 GHashTable *bitmaps_map;
231 const char *node_map_from, *node_map_to;
234 if (!id_wellformed(bmna->alias)) {
235 error_setg(errp, "The node alias '%s' is not well-formed",
240 if (strlen(bmna->alias) > UINT8_MAX) {
241 error_setg(errp, "The node alias '%s' is longer than %u bytes",
242 bmna->alias, UINT8_MAX);
246 if (strlen(bmna->node_name) > max_node_name_len) {
247 error_setg(errp, "The node name '%s' is longer than %zu bytes",
248 bmna->node_name, max_node_name_len);
253 if (g_hash_table_contains(alias_map, bmna->node_name)) {
254 error_setg(errp, "The node name '%s' is mapped twice",
259 node_map_from = bmna->node_name;
260 node_map_to = bmna->alias;
262 if (g_hash_table_contains(alias_map, bmna->alias)) {
263 error_setg(errp, "The node alias '%s' is used twice",
268 node_map_from = bmna->alias;
269 node_map_to = bmna->node_name;
272 gdn = (GDestroyNotify) qapi_free_BitmapMigrationBitmapAlias;
273 bitmaps_map = g_hash_table_new_full(g_str_hash, g_str_equal, g_free,
276 amin = g_new(AliasMapInnerNode, 1);
277 *amin = (AliasMapInnerNode){
278 .string = g_strdup(node_map_to),
279 .subtree = bitmaps_map,
282 g_hash_table_insert(alias_map, g_strdup(node_map_from), amin);
284 for (bmbal = bmna->bitmaps; bmbal; bmbal = bmbal->next) {
285 const BitmapMigrationBitmapAlias *bmba = bmbal->value;
286 const char *bmap_map_from;
288 if (strlen(bmba->alias) > UINT8_MAX) {
290 "The bitmap alias '%s' is longer than %u bytes",
291 bmba->alias, UINT8_MAX);
295 if (strlen(bmba->name) > BDRV_BITMAP_MAX_NAME_SIZE) {
296 error_setg(errp, "The bitmap name '%s' is longer than %d bytes",
297 bmba->name, BDRV_BITMAP_MAX_NAME_SIZE);
302 bmap_map_from = bmba->name;
304 if (g_hash_table_contains(bitmaps_map, bmba->name)) {
305 error_setg(errp, "The bitmap '%s'/'%s' is mapped twice",
306 bmna->node_name, bmba->name);
310 bmap_map_from = bmba->alias;
312 if (g_hash_table_contains(bitmaps_map, bmba->alias)) {
313 error_setg(errp, "The bitmap alias '%s'/'%s' is used twice",
314 bmna->alias, bmba->alias);
319 g_hash_table_insert(bitmaps_map, g_strdup(bmap_map_from),
320 QAPI_CLONE(BitmapMigrationBitmapAlias, bmba));
327 g_hash_table_destroy(alias_map);
332 * Run construct_alias_map() in both directions to check whether @bbm
334 * (This function is to be used by migration/migration.c to validate
335 * the user-specified block-bitmap-mapping migration parameter.)
337 * Returns true if and only if the mapping is valid.
339 bool check_dirty_bitmap_mig_alias_map(const BitmapMigrationNodeAliasList *bbm,
342 GHashTable *alias_map;
344 alias_map = construct_alias_map(bbm, true, errp);
348 g_hash_table_destroy(alias_map);
350 alias_map = construct_alias_map(bbm, false, errp);
354 g_hash_table_destroy(alias_map);
359 static uint32_t qemu_get_bitmap_flags(QEMUFile *f)
361 uint8_t flags = qemu_get_byte(f);
362 if (flags & DIRTY_BITMAP_MIG_EXTRA_FLAGS) {
363 flags = flags << 8 | qemu_get_byte(f);
364 if (flags & DIRTY_BITMAP_MIG_EXTRA_FLAGS) {
365 flags = flags << 16 | qemu_get_be16(f);
372 static void qemu_put_bitmap_flags(QEMUFile *f, uint32_t flags)
374 /* The code currently does not send flags as more than one byte */
375 assert(!(flags & (0xffffff00 | DIRTY_BITMAP_MIG_EXTRA_FLAGS)));
377 qemu_put_byte(f, flags);
380 static void send_bitmap_header(QEMUFile *f, DBMSaveState *s,
381 SaveBitmapState *dbms, uint32_t additional_flags)
383 BlockDriverState *bs = dbms->bs;
384 BdrvDirtyBitmap *bitmap = dbms->bitmap;
385 uint32_t flags = additional_flags;
386 trace_send_bitmap_header_enter();
388 if (bs != s->prev_bs) {
390 flags |= DIRTY_BITMAP_MIG_FLAG_DEVICE_NAME;
393 if (bitmap != s->prev_bitmap) {
394 s->prev_bitmap = bitmap;
395 flags |= DIRTY_BITMAP_MIG_FLAG_BITMAP_NAME;
398 qemu_put_bitmap_flags(f, flags);
400 if (flags & DIRTY_BITMAP_MIG_FLAG_DEVICE_NAME) {
401 qemu_put_counted_string(f, dbms->node_alias);
404 if (flags & DIRTY_BITMAP_MIG_FLAG_BITMAP_NAME) {
405 qemu_put_counted_string(f, dbms->bitmap_alias);
409 static void send_bitmap_start(QEMUFile *f, DBMSaveState *s,
410 SaveBitmapState *dbms)
412 send_bitmap_header(f, s, dbms, DIRTY_BITMAP_MIG_FLAG_START);
413 qemu_put_be32(f, bdrv_dirty_bitmap_granularity(dbms->bitmap));
414 qemu_put_byte(f, dbms->flags);
417 static void send_bitmap_complete(QEMUFile *f, DBMSaveState *s,
418 SaveBitmapState *dbms)
420 send_bitmap_header(f, s, dbms, DIRTY_BITMAP_MIG_FLAG_COMPLETE);
423 static void send_bitmap_bits(QEMUFile *f, DBMSaveState *s,
424 SaveBitmapState *dbms,
425 uint64_t start_sector, uint32_t nr_sectors)
427 /* align for buffer_is_zero() */
428 uint64_t align = 4 * sizeof(long);
429 uint64_t unaligned_size =
430 bdrv_dirty_bitmap_serialization_size(
431 dbms->bitmap, start_sector << BDRV_SECTOR_BITS,
432 (uint64_t)nr_sectors << BDRV_SECTOR_BITS);
433 uint64_t buf_size = QEMU_ALIGN_UP(unaligned_size, align);
434 uint8_t *buf = g_malloc0(buf_size);
435 uint32_t flags = DIRTY_BITMAP_MIG_FLAG_BITS;
437 bdrv_dirty_bitmap_serialize_part(
438 dbms->bitmap, buf, start_sector << BDRV_SECTOR_BITS,
439 (uint64_t)nr_sectors << BDRV_SECTOR_BITS);
441 if (buffer_is_zero(buf, buf_size)) {
444 flags |= DIRTY_BITMAP_MIG_FLAG_ZEROES;
447 trace_send_bitmap_bits(flags, start_sector, nr_sectors, buf_size);
449 send_bitmap_header(f, s, dbms, flags);
451 qemu_put_be64(f, start_sector);
452 qemu_put_be32(f, nr_sectors);
454 /* if a block is zero we need to flush here since the network
455 * bandwidth is now a lot higher than the storage device bandwidth.
456 * thus if we queue zero blocks we slow down the migration. */
457 if (flags & DIRTY_BITMAP_MIG_FLAG_ZEROES) {
460 qemu_put_be64(f, buf_size);
461 qemu_put_buffer(f, buf, buf_size);
467 /* Called with iothread lock taken. */
468 static void dirty_bitmap_do_save_cleanup(DBMSaveState *s)
470 SaveBitmapState *dbms;
472 while ((dbms = QSIMPLEQ_FIRST(&s->dbms_list)) != NULL) {
473 QSIMPLEQ_REMOVE_HEAD(&s->dbms_list, entry);
474 bdrv_dirty_bitmap_set_busy(dbms->bitmap, false);
475 bdrv_unref(dbms->bs);
476 g_free(dbms->node_alias);
477 g_free(dbms->bitmap_alias);
482 /* Called with iothread lock taken. */
483 static int add_bitmaps_to_list(DBMSaveState *s, BlockDriverState *bs,
484 const char *bs_name, GHashTable *alias_map)
486 BdrvDirtyBitmap *bitmap;
487 SaveBitmapState *dbms;
488 GHashTable *bitmap_aliases;
489 const char *node_alias, *bitmap_name, *bitmap_alias;
490 Error *local_err = NULL;
492 /* When an alias map is given, @bs_name must be @bs's node name */
493 assert(!alias_map || !strcmp(bs_name, bdrv_get_node_name(bs)));
495 FOR_EACH_DIRTY_BITMAP(bs, bitmap) {
496 if (bdrv_dirty_bitmap_name(bitmap)) {
504 bitmap_name = bdrv_dirty_bitmap_name(bitmap);
506 if (!bs_name || strcmp(bs_name, "") == 0) {
507 error_report("Bitmap '%s' in unnamed node can't be migrated",
513 const AliasMapInnerNode *amin = g_hash_table_lookup(alias_map, bs_name);
516 /* Skip bitmaps on nodes with no alias */
520 node_alias = amin->string;
521 bitmap_aliases = amin->subtree;
523 node_alias = bs_name;
524 bitmap_aliases = NULL;
527 if (node_alias[0] == '#') {
528 error_report("Bitmap '%s' in a node with auto-generated "
529 "name '%s' can't be migrated",
530 bitmap_name, node_alias);
534 FOR_EACH_DIRTY_BITMAP(bs, bitmap) {
535 BitmapMigrationBitmapAliasTransform *bitmap_transform = NULL;
536 bitmap_name = bdrv_dirty_bitmap_name(bitmap);
541 if (bdrv_dirty_bitmap_check(bitmap, BDRV_BITMAP_DEFAULT, &local_err)) {
542 error_report_err(local_err);
546 if (bitmap_aliases) {
547 BitmapMigrationBitmapAlias *bmap_inner;
549 bmap_inner = g_hash_table_lookup(bitmap_aliases, bitmap_name);
551 /* Skip bitmaps with no alias */
555 bitmap_alias = bmap_inner->alias;
556 if (bmap_inner->transform) {
557 bitmap_transform = bmap_inner->transform;
560 if (strlen(bitmap_name) > UINT8_MAX) {
561 error_report("Cannot migrate bitmap '%s' on node '%s': "
562 "Name is longer than %u bytes",
563 bitmap_name, bs_name, UINT8_MAX);
566 bitmap_alias = bitmap_name;
570 bdrv_dirty_bitmap_set_busy(bitmap, true);
572 dbms = g_new0(SaveBitmapState, 1);
574 dbms->node_alias = g_strdup(node_alias);
575 dbms->bitmap_alias = g_strdup(bitmap_alias);
576 dbms->bitmap = bitmap;
577 dbms->total_sectors = bdrv_nb_sectors(bs);
578 dbms->sectors_per_chunk = CHUNK_SIZE * 8LLU *
579 (bdrv_dirty_bitmap_granularity(bitmap) >> BDRV_SECTOR_BITS);
580 assert(dbms->sectors_per_chunk != 0);
581 if (bdrv_dirty_bitmap_enabled(bitmap)) {
582 dbms->flags |= DIRTY_BITMAP_MIG_START_FLAG_ENABLED;
584 if (bitmap_transform &&
585 bitmap_transform->has_persistent) {
586 if (bitmap_transform->persistent) {
587 dbms->flags |= DIRTY_BITMAP_MIG_START_FLAG_PERSISTENT;
590 if (bdrv_dirty_bitmap_get_persistence(bitmap)) {
591 dbms->flags |= DIRTY_BITMAP_MIG_START_FLAG_PERSISTENT;
595 QSIMPLEQ_INSERT_TAIL(&s->dbms_list, dbms, entry);
601 /* Called with iothread lock taken. */
602 static int init_dirty_bitmap_migration(DBMSaveState *s)
604 BlockDriverState *bs;
605 SaveBitmapState *dbms;
606 GHashTable *handled_by_blk = g_hash_table_new(NULL, NULL);
608 GHashTable *alias_map = NULL;
610 if (migrate_has_block_bitmap_mapping()) {
611 alias_map = construct_alias_map(migrate_block_bitmap_mapping(), true,
615 s->bulk_completed = false;
617 s->prev_bitmap = NULL;
618 s->no_bitmaps = false;
622 * Use blockdevice name for direct (or filtered) children of named block
625 for (blk = blk_next(NULL); blk; blk = blk_next(blk)) {
626 const char *name = blk_name(blk);
628 if (!name || strcmp(name, "") == 0) {
634 /* Skip filters without bitmaps */
635 while (bs && bs->drv && bs->drv->is_filter &&
636 !bdrv_has_named_bitmaps(bs))
638 bs = bdrv_filter_bs(bs);
641 if (bs && bs->drv && !bs->drv->is_filter) {
642 if (add_bitmaps_to_list(s, bs, name, NULL)) {
645 g_hash_table_add(handled_by_blk, bs);
650 for (bs = bdrv_next_all_states(NULL); bs; bs = bdrv_next_all_states(bs)) {
651 if (g_hash_table_contains(handled_by_blk, bs)) {
655 if (add_bitmaps_to_list(s, bs, bdrv_get_node_name(bs), alias_map)) {
660 /* unset migration flags here, to not roll back it */
661 QSIMPLEQ_FOREACH(dbms, &s->dbms_list, entry) {
662 bdrv_dirty_bitmap_skip_store(dbms->bitmap, true);
665 if (QSIMPLEQ_EMPTY(&s->dbms_list)) {
666 s->no_bitmaps = true;
669 g_hash_table_destroy(handled_by_blk);
671 g_hash_table_destroy(alias_map);
677 g_hash_table_destroy(handled_by_blk);
679 g_hash_table_destroy(alias_map);
681 dirty_bitmap_do_save_cleanup(s);
686 /* Called with no lock taken. */
687 static void bulk_phase_send_chunk(QEMUFile *f, DBMSaveState *s,
688 SaveBitmapState *dbms)
690 uint32_t nr_sectors = MIN(dbms->total_sectors - dbms->cur_sector,
691 dbms->sectors_per_chunk);
693 send_bitmap_bits(f, s, dbms, dbms->cur_sector, nr_sectors);
695 dbms->cur_sector += nr_sectors;
696 if (dbms->cur_sector >= dbms->total_sectors) {
697 dbms->bulk_completed = true;
701 /* Called with no lock taken. */
702 static void bulk_phase(QEMUFile *f, DBMSaveState *s, bool limit)
704 SaveBitmapState *dbms;
706 QSIMPLEQ_FOREACH(dbms, &s->dbms_list, entry) {
707 while (!dbms->bulk_completed) {
708 bulk_phase_send_chunk(f, s, dbms);
709 if (limit && migration_rate_exceeded(f)) {
715 s->bulk_completed = true;
718 /* for SaveVMHandlers */
719 static void dirty_bitmap_save_cleanup(void *opaque)
721 DBMSaveState *s = &((DBMState *)opaque)->save;
723 dirty_bitmap_do_save_cleanup(s);
726 static int dirty_bitmap_save_iterate(QEMUFile *f, void *opaque)
728 DBMSaveState *s = &((DBMState *)opaque)->save;
730 trace_dirty_bitmap_save_iterate(migration_in_postcopy());
732 if (migration_in_postcopy() && !s->bulk_completed) {
733 bulk_phase(f, s, true);
736 qemu_put_bitmap_flags(f, DIRTY_BITMAP_MIG_FLAG_EOS);
738 return s->bulk_completed;
741 /* Called with iothread lock taken. */
743 static int dirty_bitmap_save_complete(QEMUFile *f, void *opaque)
745 DBMSaveState *s = &((DBMState *)opaque)->save;
746 SaveBitmapState *dbms;
747 trace_dirty_bitmap_save_complete_enter();
749 if (!s->bulk_completed) {
750 bulk_phase(f, s, false);
753 QSIMPLEQ_FOREACH(dbms, &s->dbms_list, entry) {
754 send_bitmap_complete(f, s, dbms);
757 qemu_put_bitmap_flags(f, DIRTY_BITMAP_MIG_FLAG_EOS);
759 trace_dirty_bitmap_save_complete_finish();
761 dirty_bitmap_save_cleanup(opaque);
765 static void dirty_bitmap_state_pending(void *opaque,
766 uint64_t *must_precopy,
767 uint64_t *can_postcopy)
769 DBMSaveState *s = &((DBMState *)opaque)->save;
770 SaveBitmapState *dbms;
771 uint64_t pending = 0;
773 qemu_mutex_lock_iothread();
775 QSIMPLEQ_FOREACH(dbms, &s->dbms_list, entry) {
776 uint64_t gran = bdrv_dirty_bitmap_granularity(dbms->bitmap);
777 uint64_t sectors = dbms->bulk_completed ? 0 :
778 dbms->total_sectors - dbms->cur_sector;
780 pending += DIV_ROUND_UP(sectors * BDRV_SECTOR_SIZE, gran);
783 qemu_mutex_unlock_iothread();
785 trace_dirty_bitmap_state_pending(pending);
787 *can_postcopy += pending;
790 /* First occurrence of this bitmap. It should be created if doesn't exist */
791 static int dirty_bitmap_load_start(QEMUFile *f, DBMLoadState *s)
793 Error *local_err = NULL;
794 uint32_t granularity = qemu_get_be32(f);
795 uint8_t flags = qemu_get_byte(f);
804 error_report("Bitmap with the same name ('%s') already exists on "
805 "destination", bdrv_dirty_bitmap_name(s->bitmap));
808 s->bitmap = bdrv_create_dirty_bitmap(s->bs, granularity,
809 s->bitmap_name, &local_err);
811 error_report_err(local_err);
816 if (flags & DIRTY_BITMAP_MIG_START_FLAG_RESERVED_MASK) {
817 error_report("Unknown flags in migrated dirty bitmap header: %x",
823 s->bmap_inner->transform &&
824 s->bmap_inner->transform->has_persistent) {
825 persistent = s->bmap_inner->transform->persistent;
827 persistent = flags & DIRTY_BITMAP_MIG_START_FLAG_PERSISTENT;
831 bdrv_dirty_bitmap_set_persistence(s->bitmap, true);
834 bdrv_disable_dirty_bitmap(s->bitmap);
835 if (flags & DIRTY_BITMAP_MIG_START_FLAG_ENABLED) {
836 bdrv_dirty_bitmap_create_successor(s->bitmap, &local_err);
838 error_report_err(local_err);
842 bdrv_dirty_bitmap_set_busy(s->bitmap, true);
845 b = g_new(LoadBitmapState, 1);
847 b->bitmap = s->bitmap;
849 b->enabled = flags & DIRTY_BITMAP_MIG_START_FLAG_ENABLED;
851 s->bitmaps = g_slist_prepend(s->bitmaps, b);
857 * before_vm_start_handle_item
859 * g_slist_foreach helper
861 * item is LoadBitmapState*
862 * opaque is DBMLoadState*
864 static void before_vm_start_handle_item(void *item, void *opaque)
866 DBMLoadState *s = opaque;
867 LoadBitmapState *b = item;
871 bdrv_enable_dirty_bitmap(b->bitmap);
873 bdrv_dirty_bitmap_enable_successor(b->bitmap);
878 s->bitmaps = g_slist_remove(s->bitmaps, b);
883 void dirty_bitmap_mig_before_vm_start(void)
885 DBMLoadState *s = &dbm_state.load;
886 qemu_mutex_lock(&s->lock);
888 assert(!s->before_vm_start_handled);
889 g_slist_foreach(s->bitmaps, before_vm_start_handle_item, s);
890 s->before_vm_start_handled = true;
892 qemu_mutex_unlock(&s->lock);
895 static void cancel_incoming_locked(DBMLoadState *s)
907 /* Drop all unfinished bitmaps */
908 for (item = s->bitmaps; item; item = g_slist_next(item)) {
909 LoadBitmapState *b = item->data;
912 * Bitmap must be unfinished, as finished bitmaps should already be
913 * removed from the list.
915 assert(!s->before_vm_start_handled || !b->migrated);
916 if (bdrv_dirty_bitmap_has_successor(b->bitmap)) {
917 bdrv_reclaim_dirty_bitmap(b->bitmap, &error_abort);
919 bdrv_dirty_bitmap_set_busy(b->bitmap, false);
921 bdrv_release_dirty_bitmap(b->bitmap);
924 g_slist_free_full(s->bitmaps, g_free);
928 void dirty_bitmap_mig_cancel_outgoing(void)
930 dirty_bitmap_do_save_cleanup(&dbm_state.save);
933 void dirty_bitmap_mig_cancel_incoming(void)
935 DBMLoadState *s = &dbm_state.load;
937 qemu_mutex_lock(&s->lock);
939 cancel_incoming_locked(s);
941 qemu_mutex_unlock(&s->lock);
944 static void dirty_bitmap_load_complete(QEMUFile *f, DBMLoadState *s)
947 trace_dirty_bitmap_load_complete();
953 bdrv_dirty_bitmap_deserialize_finish(s->bitmap);
955 if (bdrv_dirty_bitmap_has_successor(s->bitmap)) {
956 bdrv_reclaim_dirty_bitmap(s->bitmap, &error_abort);
958 bdrv_dirty_bitmap_set_busy(s->bitmap, false);
961 for (item = s->bitmaps; item; item = g_slist_next(item)) {
962 LoadBitmapState *b = item->data;
964 if (b->bitmap == s->bitmap) {
966 if (s->before_vm_start_handled) {
967 s->bitmaps = g_slist_remove(s->bitmaps, b);
975 static int dirty_bitmap_load_bits(QEMUFile *f, DBMLoadState *s)
977 uint64_t first_byte = qemu_get_be64(f) << BDRV_SECTOR_BITS;
978 uint64_t nr_bytes = (uint64_t)qemu_get_be32(f) << BDRV_SECTOR_BITS;
979 trace_dirty_bitmap_load_bits_enter(first_byte >> BDRV_SECTOR_BITS,
980 nr_bytes >> BDRV_SECTOR_BITS);
982 if (s->flags & DIRTY_BITMAP_MIG_FLAG_ZEROES) {
983 trace_dirty_bitmap_load_bits_zeroes();
985 bdrv_dirty_bitmap_deserialize_zeroes(s->bitmap, first_byte,
990 g_autofree uint8_t *buf = NULL;
991 uint64_t buf_size = qemu_get_be64(f);
992 uint64_t needed_size;
995 * The actual check for buf_size is done a bit later. We can't do it in
996 * cancelled mode as we don't have the bitmap to check the constraints
997 * (so, we allocate a buffer and read prior to the check). On the other
998 * hand, we shouldn't blindly g_malloc the number from the stream.
999 * Actually one chunk should not be larger than CHUNK_SIZE. Let's allow
1000 * a bit larger (which means that bitmap migration will fail anyway and
1001 * the whole migration will most probably fail soon due to broken
1004 if (buf_size > 10 * CHUNK_SIZE) {
1005 error_report("Bitmap migration stream buffer allocation request "
1010 buf = g_malloc(buf_size);
1011 ret = qemu_get_buffer(f, buf, buf_size);
1012 if (ret != buf_size) {
1013 error_report("Failed to read bitmap bits");
1021 needed_size = bdrv_dirty_bitmap_serialization_size(s->bitmap,
1025 if (needed_size > buf_size ||
1026 buf_size > QEMU_ALIGN_UP(needed_size, 4 * sizeof(long))
1027 /* Here used same alignment as in send_bitmap_bits */
1029 error_report("Migrated bitmap granularity doesn't "
1030 "match the destination bitmap '%s' granularity",
1031 bdrv_dirty_bitmap_name(s->bitmap));
1032 cancel_incoming_locked(s);
1036 bdrv_dirty_bitmap_deserialize_part(s->bitmap, buf, first_byte, nr_bytes,
1043 static int dirty_bitmap_load_header(QEMUFile *f, DBMLoadState *s,
1044 GHashTable *alias_map)
1046 GHashTable *bitmap_alias_map = NULL;
1047 Error *local_err = NULL;
1049 s->flags = qemu_get_bitmap_flags(f);
1050 trace_dirty_bitmap_load_header(s->flags);
1052 nothing = s->flags == (s->flags & DIRTY_BITMAP_MIG_FLAG_EOS);
1054 if (s->flags & DIRTY_BITMAP_MIG_FLAG_DEVICE_NAME) {
1055 if (!qemu_get_counted_string(f, s->node_alias)) {
1056 error_report("Unable to read node alias string");
1060 if (!s->cancelled) {
1062 const AliasMapInnerNode *amin;
1064 amin = g_hash_table_lookup(alias_map, s->node_alias);
1066 error_setg(&local_err, "Error: Unknown node alias '%s'",
1070 bitmap_alias_map = amin->subtree;
1071 s->bs = bdrv_lookup_bs(NULL, amin->string, &local_err);
1074 s->bs = bdrv_lookup_bs(s->node_alias, s->node_alias,
1078 error_report_err(local_err);
1079 cancel_incoming_locked(s);
1084 const AliasMapInnerNode *amin;
1086 /* Must be present in the map, or s->bs would not be set */
1087 amin = g_hash_table_lookup(alias_map, s->node_alias);
1088 assert(amin != NULL);
1090 bitmap_alias_map = amin->subtree;
1092 } else if (!nothing && !s->cancelled) {
1093 error_report("Error: block device name is not set");
1094 cancel_incoming_locked(s);
1097 assert(nothing || s->cancelled || !!alias_map == !!bitmap_alias_map);
1099 if (s->flags & DIRTY_BITMAP_MIG_FLAG_BITMAP_NAME) {
1100 const char *bitmap_name;
1102 if (!qemu_get_counted_string(f, s->bitmap_alias)) {
1103 error_report("Unable to read bitmap alias string");
1107 bitmap_name = s->bitmap_alias;
1108 if (!s->cancelled && bitmap_alias_map) {
1109 BitmapMigrationBitmapAlias *bmap_inner;
1111 bmap_inner = g_hash_table_lookup(bitmap_alias_map, s->bitmap_alias);
1113 error_report("Error: Unknown bitmap alias '%s' on node "
1114 "'%s' (alias '%s')", s->bitmap_alias,
1115 s->bs->node_name, s->node_alias);
1116 cancel_incoming_locked(s);
1118 bitmap_name = bmap_inner->name;
1121 s->bmap_inner = bmap_inner;
1124 if (!s->cancelled) {
1125 g_strlcpy(s->bitmap_name, bitmap_name, sizeof(s->bitmap_name));
1126 s->bitmap = bdrv_find_dirty_bitmap(s->bs, s->bitmap_name);
1129 * bitmap may be NULL here, it wouldn't be an error if it is the
1130 * first occurrence of the bitmap
1132 if (!s->bitmap && !(s->flags & DIRTY_BITMAP_MIG_FLAG_START)) {
1133 error_report("Error: unknown dirty bitmap "
1134 "'%s' for block device '%s'",
1135 s->bitmap_name, s->bs->node_name);
1136 cancel_incoming_locked(s);
1139 } else if (!s->bitmap && !nothing && !s->cancelled) {
1140 error_report("Error: block device name is not set");
1141 cancel_incoming_locked(s);
1150 * Load sequence of dirty bitmap chunks. Return error only on fatal io stream
1151 * violations. On other errors just cancel bitmaps incoming migration and return
1154 * Note, than when incoming bitmap migration is canceled, we still must read all
1155 * our chunks (and just ignore them), to not affect other migration objects.
1157 static int dirty_bitmap_load(QEMUFile *f, void *opaque, int version_id)
1159 GHashTable *alias_map = NULL;
1160 DBMLoadState *s = &((DBMState *)opaque)->load;
1163 trace_dirty_bitmap_load_enter();
1165 if (version_id != 1) {
1166 QEMU_LOCK_GUARD(&s->lock);
1167 cancel_incoming_locked(s);
1171 if (migrate_has_block_bitmap_mapping()) {
1172 alias_map = construct_alias_map(migrate_block_bitmap_mapping(), false,
1177 QEMU_LOCK_GUARD(&s->lock);
1179 ret = dirty_bitmap_load_header(f, s, alias_map);
1181 cancel_incoming_locked(s);
1185 if (s->flags & DIRTY_BITMAP_MIG_FLAG_START) {
1186 ret = dirty_bitmap_load_start(f, s);
1187 } else if (s->flags & DIRTY_BITMAP_MIG_FLAG_COMPLETE) {
1188 dirty_bitmap_load_complete(f, s);
1189 } else if (s->flags & DIRTY_BITMAP_MIG_FLAG_BITS) {
1190 ret = dirty_bitmap_load_bits(f, s);
1194 ret = qemu_file_get_error(f);
1198 cancel_incoming_locked(s);
1201 } while (!(s->flags & DIRTY_BITMAP_MIG_FLAG_EOS));
1203 trace_dirty_bitmap_load_success();
1207 g_hash_table_destroy(alias_map);
1212 static int dirty_bitmap_save_setup(QEMUFile *f, void *opaque)
1214 DBMSaveState *s = &((DBMState *)opaque)->save;
1215 SaveBitmapState *dbms = NULL;
1217 qemu_mutex_lock_iothread();
1218 if (init_dirty_bitmap_migration(s) < 0) {
1219 qemu_mutex_unlock_iothread();
1223 QSIMPLEQ_FOREACH(dbms, &s->dbms_list, entry) {
1224 send_bitmap_start(f, s, dbms);
1226 qemu_put_bitmap_flags(f, DIRTY_BITMAP_MIG_FLAG_EOS);
1227 qemu_mutex_unlock_iothread();
1231 static bool dirty_bitmap_is_active(void *opaque)
1233 DBMSaveState *s = &((DBMState *)opaque)->save;
1235 return migrate_dirty_bitmaps() && !s->no_bitmaps;
1238 static bool dirty_bitmap_is_active_iterate(void *opaque)
1240 return dirty_bitmap_is_active(opaque) && !runstate_is_running();
1243 static bool dirty_bitmap_has_postcopy(void *opaque)
1248 static SaveVMHandlers savevm_dirty_bitmap_handlers = {
1249 .save_setup = dirty_bitmap_save_setup,
1250 .save_live_complete_postcopy = dirty_bitmap_save_complete,
1251 .save_live_complete_precopy = dirty_bitmap_save_complete,
1252 .has_postcopy = dirty_bitmap_has_postcopy,
1253 .state_pending_exact = dirty_bitmap_state_pending,
1254 .state_pending_estimate = dirty_bitmap_state_pending,
1255 .save_live_iterate = dirty_bitmap_save_iterate,
1256 .is_active_iterate = dirty_bitmap_is_active_iterate,
1257 .load_state = dirty_bitmap_load,
1258 .save_cleanup = dirty_bitmap_save_cleanup,
1259 .is_active = dirty_bitmap_is_active,
1262 void dirty_bitmap_mig_init(void)
1264 QSIMPLEQ_INIT(&dbm_state.save.dbms_list);
1265 qemu_mutex_init(&dbm_state.load.lock);
1267 register_savevm_live("dirty-bitmap", 0, 1,
1268 &savevm_dirty_bitmap_handlers,