/* * Block dirty bitmap postcopy migration * * Copyright IBM, Corp. 2009 * Copyright (c) 2016-2017 Virtuozzo International GmbH. All rights reserved. * * Authors: * Liran Schour * Vladimir Sementsov-Ogievskiy * * This work is licensed under the terms of the GNU GPL, version 2. See * the COPYING file in the top-level directory. * This file is derived from migration/block.c, so it's author and IBM copyright * are here, although content is quite different. * * Contributions after 2012-01-13 are licensed under the terms of the * GNU GPL, version 2 or (at your option) any later version. * * *** * * Here postcopy migration of dirty bitmaps is realized. Only QMP-addressable * bitmaps are migrated. * * Bitmap migration implies creating bitmap with the same name and granularity * in destination QEMU. If the bitmap with the same name (for the same node) * already exists on destination an error will be generated. * * format of migration: * * # Header (shared for different chunk types) * 1, 2 or 4 bytes: flags (see qemu_{put,put}_flags) * [ 1 byte: node alias size ] \ flags & DEVICE_NAME * [ n bytes: node alias ] / * [ 1 byte: bitmap alias size ] \ flags & BITMAP_NAME * [ n bytes: bitmap alias ] / * * # Start of bitmap migration (flags & START) * header * be64: granularity * 1 byte: bitmap flags (corresponds to BdrvDirtyBitmap) * bit 0 - bitmap is enabled * bit 1 - bitmap is persistent * bit 2 - bitmap is autoloading * bits 3-7 - reserved, must be zero * * # Complete of bitmap migration (flags & COMPLETE) * header * * # Data chunk of bitmap migration * header * be64: start sector * be32: number of sectors * [ be64: buffer size ] \ ! (flags & ZEROES) * [ n bytes: buffer ] / * * The last chunk in stream should contain flags & EOS. The chunk may skip * device and/or bitmap names, assuming them to be the same with the previous * chunk. */ #include "qemu/osdep.h" #include "block/block.h" #include "block/block_int.h" #include "block/dirty-bitmap.h" #include "sysemu/block-backend.h" #include "sysemu/runstate.h" #include "qemu/main-loop.h" #include "qemu/error-report.h" #include "migration/misc.h" #include "migration/migration.h" #include "qemu-file.h" #include "migration/vmstate.h" #include "migration/register.h" #include "qemu/hbitmap.h" #include "qemu/cutils.h" #include "qemu/id.h" #include "qapi/error.h" #include "qapi/qapi-commands-migration.h" #include "qapi/qapi-visit-migration.h" #include "qapi/clone-visitor.h" #include "trace.h" #define CHUNK_SIZE (1 << 10) /* Flags occupy one, two or four bytes (Big Endian). The size is determined as * follows: * in first (most significant) byte bit 8 is clear --> one byte * in first byte bit 8 is set --> two or four bytes, depending on second * byte: * | in second byte bit 8 is clear --> two bytes * | in second byte bit 8 is set --> four bytes */ #define DIRTY_BITMAP_MIG_FLAG_EOS 0x01 #define DIRTY_BITMAP_MIG_FLAG_ZEROES 0x02 #define DIRTY_BITMAP_MIG_FLAG_BITMAP_NAME 0x04 #define DIRTY_BITMAP_MIG_FLAG_DEVICE_NAME 0x08 #define DIRTY_BITMAP_MIG_FLAG_START 0x10 #define DIRTY_BITMAP_MIG_FLAG_COMPLETE 0x20 #define DIRTY_BITMAP_MIG_FLAG_BITS 0x40 #define DIRTY_BITMAP_MIG_EXTRA_FLAGS 0x80 #define DIRTY_BITMAP_MIG_START_FLAG_ENABLED 0x01 #define DIRTY_BITMAP_MIG_START_FLAG_PERSISTENT 0x02 /* 0x04 was "AUTOLOAD" flags on older versions, now it is ignored */ #define DIRTY_BITMAP_MIG_START_FLAG_RESERVED_MASK 0xf8 /* State of one bitmap during save process */ typedef struct SaveBitmapState { /* Written during setup phase. */ BlockDriverState *bs; char *node_alias; char *bitmap_alias; BdrvDirtyBitmap *bitmap; uint64_t total_sectors; uint64_t sectors_per_chunk; QSIMPLEQ_ENTRY(SaveBitmapState) entry; uint8_t flags; /* For bulk phase. */ bool bulk_completed; uint64_t cur_sector; } SaveBitmapState; /* State of the dirty bitmap migration (DBM) during save process */ typedef struct DBMSaveState { QSIMPLEQ_HEAD(, SaveBitmapState) dbms_list; bool bulk_completed; bool no_bitmaps; /* for send_bitmap_bits() */ BlockDriverState *prev_bs; BdrvDirtyBitmap *prev_bitmap; } DBMSaveState; typedef struct LoadBitmapState { BlockDriverState *bs; BdrvDirtyBitmap *bitmap; bool migrated; bool enabled; } LoadBitmapState; /* State of the dirty bitmap migration (DBM) during load process */ typedef struct DBMLoadState { uint32_t flags; char node_alias[256]; char bitmap_alias[256]; char bitmap_name[BDRV_BITMAP_MAX_NAME_SIZE + 1]; BlockDriverState *bs; BdrvDirtyBitmap *bitmap; bool before_vm_start_handled; /* set in dirty_bitmap_mig_before_vm_start */ BitmapMigrationBitmapAlias *bmap_inner; /* * cancelled * Incoming migration is cancelled for some reason. That means that we * still should read our chunks from migration stream, to not affect other * migration objects (like RAM), but just ignore them and do not touch any * bitmaps or nodes. */ bool cancelled; GSList *bitmaps; QemuMutex lock; /* protect bitmaps */ } DBMLoadState; typedef struct DBMState { DBMSaveState save; DBMLoadState load; } DBMState; static DBMState dbm_state; /* For hash tables that map node/bitmap names to aliases */ typedef struct AliasMapInnerNode { char *string; GHashTable *subtree; } AliasMapInnerNode; static void free_alias_map_inner_node(void *amin_ptr) { AliasMapInnerNode *amin = amin_ptr; g_free(amin->string); g_hash_table_unref(amin->subtree); g_free(amin); } /** * Construct an alias map based on the given QMP structure. * * (Note that we cannot store such maps in the MigrationParameters * object, because that struct is defined by the QAPI schema, which * makes it basically impossible to have dicts with arbitrary keys. * Therefore, we instead have to construct these maps when migration * starts.) * * @bbm is the block_bitmap_mapping from the migration parameters. * * If @name_to_alias is true, the returned hash table will map node * and bitmap names to their respective aliases (for outgoing * migration). * * If @name_to_alias is false, the returned hash table will map node * and bitmap aliases to their respective names (for incoming * migration). * * The hash table maps node names/aliases to AliasMapInnerNode * objects, whose .string is the respective node alias/name, and whose * .subtree table maps bitmap names/aliases to the respective bitmap * alias/name. */ static GHashTable *construct_alias_map(const BitmapMigrationNodeAliasList *bbm, bool name_to_alias, Error **errp) { GHashTable *alias_map; size_t max_node_name_len = sizeof_field(BlockDriverState, node_name) - 1; alias_map = g_hash_table_new_full(g_str_hash, g_str_equal, g_free, free_alias_map_inner_node); for (; bbm; bbm = bbm->next) { const BitmapMigrationNodeAlias *bmna = bbm->value; const BitmapMigrationBitmapAliasList *bmbal; AliasMapInnerNode *amin; GHashTable *bitmaps_map; const char *node_map_from, *node_map_to; GDestroyNotify gdn; if (!id_wellformed(bmna->alias)) { error_setg(errp, "The node alias '%s' is not well-formed", bmna->alias); goto fail; } if (strlen(bmna->alias) > UINT8_MAX) { error_setg(errp, "The node alias '%s' is longer than %u bytes", bmna->alias, UINT8_MAX); goto fail; } if (strlen(bmna->node_name) > max_node_name_len) { error_setg(errp, "The node name '%s' is longer than %zu bytes", bmna->node_name, max_node_name_len); goto fail; } if (name_to_alias) { if (g_hash_table_contains(alias_map, bmna->node_name)) { error_setg(errp, "The node name '%s' is mapped twice", bmna->node_name); goto fail; } node_map_from = bmna->node_name; node_map_to = bmna->alias; } else { if (g_hash_table_contains(alias_map, bmna->alias)) { error_setg(errp, "The node alias '%s' is used twice", bmna->alias); goto fail; } node_map_from = bmna->alias; node_map_to = bmna->node_name; } gdn = (GDestroyNotify) qapi_free_BitmapMigrationBitmapAlias; bitmaps_map = g_hash_table_new_full(g_str_hash, g_str_equal, g_free, gdn); amin = g_new(AliasMapInnerNode, 1); *amin = (AliasMapInnerNode){ .string = g_strdup(node_map_to), .subtree = bitmaps_map, }; g_hash_table_insert(alias_map, g_strdup(node_map_from), amin); for (bmbal = bmna->bitmaps; bmbal; bmbal = bmbal->next) { const BitmapMigrationBitmapAlias *bmba = bmbal->value; const char *bmap_map_from; if (strlen(bmba->alias) > UINT8_MAX) { error_setg(errp, "The bitmap alias '%s' is longer than %u bytes", bmba->alias, UINT8_MAX); goto fail; } if (strlen(bmba->name) > BDRV_BITMAP_MAX_NAME_SIZE) { error_setg(errp, "The bitmap name '%s' is longer than %d bytes", bmba->name, BDRV_BITMAP_MAX_NAME_SIZE); goto fail; } if (name_to_alias) { bmap_map_from = bmba->name; if (g_hash_table_contains(bitmaps_map, bmba->name)) { error_setg(errp, "The bitmap '%s'/'%s' is mapped twice", bmna->node_name, bmba->name); goto fail; } } else { bmap_map_from = bmba->alias; if (g_hash_table_contains(bitmaps_map, bmba->alias)) { error_setg(errp, "The bitmap alias '%s'/'%s' is used twice", bmna->alias, bmba->alias); goto fail; } } g_hash_table_insert(bitmaps_map, g_strdup(bmap_map_from), QAPI_CLONE(BitmapMigrationBitmapAlias, bmba)); } } return alias_map; fail: g_hash_table_destroy(alias_map); return NULL; } /** * Run construct_alias_map() in both directions to check whether @bbm * is valid. * (This function is to be used by migration/migration.c to validate * the user-specified block-bitmap-mapping migration parameter.) * * Returns true if and only if the mapping is valid. */ bool check_dirty_bitmap_mig_alias_map(const BitmapMigrationNodeAliasList *bbm, Error **errp) { GHashTable *alias_map; alias_map = construct_alias_map(bbm, true, errp); if (!alias_map) { return false; } g_hash_table_destroy(alias_map); alias_map = construct_alias_map(bbm, false, errp); if (!alias_map) { return false; } g_hash_table_destroy(alias_map); return true; } static uint32_t qemu_get_bitmap_flags(QEMUFile *f) { uint8_t flags = qemu_get_byte(f); if (flags & DIRTY_BITMAP_MIG_EXTRA_FLAGS) { flags = flags << 8 | qemu_get_byte(f); if (flags & DIRTY_BITMAP_MIG_EXTRA_FLAGS) { flags = flags << 16 | qemu_get_be16(f); } } return flags; } static void qemu_put_bitmap_flags(QEMUFile *f, uint32_t flags) { /* The code currently does not send flags as more than one byte */ assert(!(flags & (0xffffff00 | DIRTY_BITMAP_MIG_EXTRA_FLAGS))); qemu_put_byte(f, flags); } static void send_bitmap_header(QEMUFile *f, DBMSaveState *s, SaveBitmapState *dbms, uint32_t additional_flags) { BlockDriverState *bs = dbms->bs; BdrvDirtyBitmap *bitmap = dbms->bitmap; uint32_t flags = additional_flags; trace_send_bitmap_header_enter(); if (bs != s->prev_bs) { s->prev_bs = bs; flags |= DIRTY_BITMAP_MIG_FLAG_DEVICE_NAME; } if (bitmap != s->prev_bitmap) { s->prev_bitmap = bitmap; flags |= DIRTY_BITMAP_MIG_FLAG_BITMAP_NAME; } qemu_put_bitmap_flags(f, flags); if (flags & DIRTY_BITMAP_MIG_FLAG_DEVICE_NAME) { qemu_put_counted_string(f, dbms->node_alias); } if (flags & DIRTY_BITMAP_MIG_FLAG_BITMAP_NAME) { qemu_put_counted_string(f, dbms->bitmap_alias); } } static void send_bitmap_start(QEMUFile *f, DBMSaveState *s, SaveBitmapState *dbms) { send_bitmap_header(f, s, dbms, DIRTY_BITMAP_MIG_FLAG_START); qemu_put_be32(f, bdrv_dirty_bitmap_granularity(dbms->bitmap)); qemu_put_byte(f, dbms->flags); } static void send_bitmap_complete(QEMUFile *f, DBMSaveState *s, SaveBitmapState *dbms) { send_bitmap_header(f, s, dbms, DIRTY_BITMAP_MIG_FLAG_COMPLETE); } static void send_bitmap_bits(QEMUFile *f, DBMSaveState *s, SaveBitmapState *dbms, uint64_t start_sector, uint32_t nr_sectors) { /* align for buffer_is_zero() */ uint64_t align = 4 * sizeof(long); uint64_t unaligned_size = bdrv_dirty_bitmap_serialization_size( dbms->bitmap, start_sector << BDRV_SECTOR_BITS, (uint64_t)nr_sectors << BDRV_SECTOR_BITS); uint64_t buf_size = QEMU_ALIGN_UP(unaligned_size, align); uint8_t *buf = g_malloc0(buf_size); uint32_t flags = DIRTY_BITMAP_MIG_FLAG_BITS; bdrv_dirty_bitmap_serialize_part( dbms->bitmap, buf, start_sector << BDRV_SECTOR_BITS, (uint64_t)nr_sectors << BDRV_SECTOR_BITS); if (buffer_is_zero(buf, buf_size)) { g_free(buf); buf = NULL; flags |= DIRTY_BITMAP_MIG_FLAG_ZEROES; } trace_send_bitmap_bits(flags, start_sector, nr_sectors, buf_size); send_bitmap_header(f, s, dbms, flags); qemu_put_be64(f, start_sector); qemu_put_be32(f, nr_sectors); /* if a block is zero we need to flush here since the network * bandwidth is now a lot higher than the storage device bandwidth. * thus if we queue zero blocks we slow down the migration. */ if (flags & DIRTY_BITMAP_MIG_FLAG_ZEROES) { qemu_fflush(f); } else { qemu_put_be64(f, buf_size); qemu_put_buffer(f, buf, buf_size); } g_free(buf); } /* Called with iothread lock taken. */ static void dirty_bitmap_do_save_cleanup(DBMSaveState *s) { SaveBitmapState *dbms; while ((dbms = QSIMPLEQ_FIRST(&s->dbms_list)) != NULL) { QSIMPLEQ_REMOVE_HEAD(&s->dbms_list, entry); bdrv_dirty_bitmap_set_busy(dbms->bitmap, false); bdrv_unref(dbms->bs); g_free(dbms->node_alias); g_free(dbms->bitmap_alias); g_free(dbms); } } /* Called with iothread lock taken. */ static int add_bitmaps_to_list(DBMSaveState *s, BlockDriverState *bs, const char *bs_name, GHashTable *alias_map) { BdrvDirtyBitmap *bitmap; SaveBitmapState *dbms; GHashTable *bitmap_aliases; const char *node_alias, *bitmap_name, *bitmap_alias; Error *local_err = NULL; /* When an alias map is given, @bs_name must be @bs's node name */ assert(!alias_map || !strcmp(bs_name, bdrv_get_node_name(bs))); FOR_EACH_DIRTY_BITMAP(bs, bitmap) { if (bdrv_dirty_bitmap_name(bitmap)) { break; } } if (!bitmap) { return 0; } bitmap_name = bdrv_dirty_bitmap_name(bitmap); if (!bs_name || strcmp(bs_name, "") == 0) { error_report("Bitmap '%s' in unnamed node can't be migrated", bitmap_name); return -1; } if (alias_map) { const AliasMapInnerNode *amin = g_hash_table_lookup(alias_map, bs_name); if (!amin) { /* Skip bitmaps on nodes with no alias */ return 0; } node_alias = amin->string; bitmap_aliases = amin->subtree; } else { node_alias = bs_name; bitmap_aliases = NULL; } if (node_alias[0] == '#') { error_report("Bitmap '%s' in a node with auto-generated " "name '%s' can't be migrated", bitmap_name, node_alias); return -1; } FOR_EACH_DIRTY_BITMAP(bs, bitmap) { BitmapMigrationBitmapAliasTransform *bitmap_transform = NULL; bitmap_name = bdrv_dirty_bitmap_name(bitmap); if (!bitmap_name) { continue; } if (bdrv_dirty_bitmap_check(bitmap, BDRV_BITMAP_DEFAULT, &local_err)) { error_report_err(local_err); return -1; } if (bitmap_aliases) { BitmapMigrationBitmapAlias *bmap_inner; bmap_inner = g_hash_table_lookup(bitmap_aliases, bitmap_name); if (!bmap_inner) { /* Skip bitmaps with no alias */ continue; } bitmap_alias = bmap_inner->alias; if (bmap_inner->transform) { bitmap_transform = bmap_inner->transform; } } else { if (strlen(bitmap_name) > UINT8_MAX) { error_report("Cannot migrate bitmap '%s' on node '%s': " "Name is longer than %u bytes", bitmap_name, bs_name, UINT8_MAX); return -1; } bitmap_alias = bitmap_name; } bdrv_ref(bs); bdrv_dirty_bitmap_set_busy(bitmap, true); dbms = g_new0(SaveBitmapState, 1); dbms->bs = bs; dbms->node_alias = g_strdup(node_alias); dbms->bitmap_alias = g_strdup(bitmap_alias); dbms->bitmap = bitmap; dbms->total_sectors = bdrv_nb_sectors(bs); dbms->sectors_per_chunk = CHUNK_SIZE * 8LLU * (bdrv_dirty_bitmap_granularity(bitmap) >> BDRV_SECTOR_BITS); assert(dbms->sectors_per_chunk != 0); if (bdrv_dirty_bitmap_enabled(bitmap)) { dbms->flags |= DIRTY_BITMAP_MIG_START_FLAG_ENABLED; } if (bitmap_transform && bitmap_transform->has_persistent) { if (bitmap_transform->persistent) { dbms->flags |= DIRTY_BITMAP_MIG_START_FLAG_PERSISTENT; } } else { if (bdrv_dirty_bitmap_get_persistence(bitmap)) { dbms->flags |= DIRTY_BITMAP_MIG_START_FLAG_PERSISTENT; } } QSIMPLEQ_INSERT_TAIL(&s->dbms_list, dbms, entry); } return 0; } /* Called with iothread lock taken. */ static int init_dirty_bitmap_migration(DBMSaveState *s) { BlockDriverState *bs; SaveBitmapState *dbms; GHashTable *handled_by_blk = g_hash_table_new(NULL, NULL); BlockBackend *blk; const MigrationParameters *mig_params = &migrate_get_current()->parameters; GHashTable *alias_map = NULL; if (mig_params->has_block_bitmap_mapping) { alias_map = construct_alias_map(mig_params->block_bitmap_mapping, true, &error_abort); } s->bulk_completed = false; s->prev_bs = NULL; s->prev_bitmap = NULL; s->no_bitmaps = false; if (!alias_map) { /* * Use blockdevice name for direct (or filtered) children of named block * backends. */ for (blk = blk_next(NULL); blk; blk = blk_next(blk)) { const char *name = blk_name(blk); if (!name || strcmp(name, "") == 0) { continue; } bs = blk_bs(blk); /* Skip filters without bitmaps */ while (bs && bs->drv && bs->drv->is_filter && !bdrv_has_named_bitmaps(bs)) { bs = bdrv_filter_bs(bs); } if (bs && bs->drv && !bs->drv->is_filter) { if (add_bitmaps_to_list(s, bs, name, NULL)) { goto fail; } g_hash_table_add(handled_by_blk, bs); } } } for (bs = bdrv_next_all_states(NULL); bs; bs = bdrv_next_all_states(bs)) { if (g_hash_table_contains(handled_by_blk, bs)) { continue; } if (add_bitmaps_to_list(s, bs, bdrv_get_node_name(bs), alias_map)) { goto fail; } } /* unset migration flags here, to not roll back it */ QSIMPLEQ_FOREACH(dbms, &s->dbms_list, entry) { bdrv_dirty_bitmap_skip_store(dbms->bitmap, true); } if (QSIMPLEQ_EMPTY(&s->dbms_list)) { s->no_bitmaps = true; } g_hash_table_destroy(handled_by_blk); if (alias_map) { g_hash_table_destroy(alias_map); } return 0; fail: g_hash_table_destroy(handled_by_blk); if (alias_map) { g_hash_table_destroy(alias_map); } dirty_bitmap_do_save_cleanup(s); return -1; } /* Called with no lock taken. */ static void bulk_phase_send_chunk(QEMUFile *f, DBMSaveState *s, SaveBitmapState *dbms) { uint32_t nr_sectors = MIN(dbms->total_sectors - dbms->cur_sector, dbms->sectors_per_chunk); send_bitmap_bits(f, s, dbms, dbms->cur_sector, nr_sectors); dbms->cur_sector += nr_sectors; if (dbms->cur_sector >= dbms->total_sectors) { dbms->bulk_completed = true; } } /* Called with no lock taken. */ static void bulk_phase(QEMUFile *f, DBMSaveState *s, bool limit) { SaveBitmapState *dbms; QSIMPLEQ_FOREACH(dbms, &s->dbms_list, entry) { while (!dbms->bulk_completed) { bulk_phase_send_chunk(f, s, dbms); if (limit && qemu_file_rate_limit(f)) { return; } } } s->bulk_completed = true; } /* for SaveVMHandlers */ static void dirty_bitmap_save_cleanup(void *opaque) { DBMSaveState *s = &((DBMState *)opaque)->save; dirty_bitmap_do_save_cleanup(s); } static int dirty_bitmap_save_iterate(QEMUFile *f, void *opaque) { DBMSaveState *s = &((DBMState *)opaque)->save; trace_dirty_bitmap_save_iterate(migration_in_postcopy()); if (migration_in_postcopy() && !s->bulk_completed) { bulk_phase(f, s, true); } qemu_put_bitmap_flags(f, DIRTY_BITMAP_MIG_FLAG_EOS); return s->bulk_completed; } /* Called with iothread lock taken. */ static int dirty_bitmap_save_complete(QEMUFile *f, void *opaque) { DBMSaveState *s = &((DBMState *)opaque)->save; SaveBitmapState *dbms; trace_dirty_bitmap_save_complete_enter(); if (!s->bulk_completed) { bulk_phase(f, s, false); } QSIMPLEQ_FOREACH(dbms, &s->dbms_list, entry) { send_bitmap_complete(f, s, dbms); } qemu_put_bitmap_flags(f, DIRTY_BITMAP_MIG_FLAG_EOS); trace_dirty_bitmap_save_complete_finish(); dirty_bitmap_save_cleanup(opaque); return 0; } static void dirty_bitmap_state_pending(void *opaque, uint64_t *res_precopy_only, uint64_t *res_postcopy_only) { DBMSaveState *s = &((DBMState *)opaque)->save; SaveBitmapState *dbms; uint64_t pending = 0; qemu_mutex_lock_iothread(); QSIMPLEQ_FOREACH(dbms, &s->dbms_list, entry) { uint64_t gran = bdrv_dirty_bitmap_granularity(dbms->bitmap); uint64_t sectors = dbms->bulk_completed ? 0 : dbms->total_sectors - dbms->cur_sector; pending += DIV_ROUND_UP(sectors * BDRV_SECTOR_SIZE, gran); } qemu_mutex_unlock_iothread(); trace_dirty_bitmap_state_pending(pending); *res_postcopy_only += pending; } /* First occurrence of this bitmap. It should be created if doesn't exist */ static int dirty_bitmap_load_start(QEMUFile *f, DBMLoadState *s) { Error *local_err = NULL; uint32_t granularity = qemu_get_be32(f); uint8_t flags = qemu_get_byte(f); LoadBitmapState *b; bool persistent; if (s->cancelled) { return 0; } if (s->bitmap) { error_report("Bitmap with the same name ('%s') already exists on " "destination", bdrv_dirty_bitmap_name(s->bitmap)); return -EINVAL; } else { s->bitmap = bdrv_create_dirty_bitmap(s->bs, granularity, s->bitmap_name, &local_err); if (!s->bitmap) { error_report_err(local_err); return -EINVAL; } } if (flags & DIRTY_BITMAP_MIG_START_FLAG_RESERVED_MASK) { error_report("Unknown flags in migrated dirty bitmap header: %x", flags); return -EINVAL; } if (s->bmap_inner && s->bmap_inner->transform && s->bmap_inner->transform->has_persistent) { persistent = s->bmap_inner->transform->persistent; } else { persistent = flags & DIRTY_BITMAP_MIG_START_FLAG_PERSISTENT; } if (persistent) { bdrv_dirty_bitmap_set_persistence(s->bitmap, true); } bdrv_disable_dirty_bitmap(s->bitmap); if (flags & DIRTY_BITMAP_MIG_START_FLAG_ENABLED) { bdrv_dirty_bitmap_create_successor(s->bitmap, &local_err); if (local_err) { error_report_err(local_err); return -EINVAL; } } else { bdrv_dirty_bitmap_set_busy(s->bitmap, true); } b = g_new(LoadBitmapState, 1); b->bs = s->bs; b->bitmap = s->bitmap; b->migrated = false; b->enabled = flags & DIRTY_BITMAP_MIG_START_FLAG_ENABLED; s->bitmaps = g_slist_prepend(s->bitmaps, b); return 0; } /* * before_vm_start_handle_item * * g_slist_foreach helper * * item is LoadBitmapState* * opaque is DBMLoadState* */ static void before_vm_start_handle_item(void *item, void *opaque) { DBMLoadState *s = opaque; LoadBitmapState *b = item; if (b->enabled) { if (b->migrated) { bdrv_enable_dirty_bitmap(b->bitmap); } else { bdrv_dirty_bitmap_enable_successor(b->bitmap); } } if (b->migrated) { s->bitmaps = g_slist_remove(s->bitmaps, b); g_free(b); } } void dirty_bitmap_mig_before_vm_start(void) { DBMLoadState *s = &dbm_state.load; qemu_mutex_lock(&s->lock); assert(!s->before_vm_start_handled); g_slist_foreach(s->bitmaps, before_vm_start_handle_item, s); s->before_vm_start_handled = true; qemu_mutex_unlock(&s->lock); } static void cancel_incoming_locked(DBMLoadState *s) { GSList *item; if (s->cancelled) { return; } s->cancelled = true; s->bs = NULL; s->bitmap = NULL; /* Drop all unfinished bitmaps */ for (item = s->bitmaps; item; item = g_slist_next(item)) { LoadBitmapState *b = item->data; /* * Bitmap must be unfinished, as finished bitmaps should already be * removed from the list. */ assert(!s->before_vm_start_handled || !b->migrated); if (bdrv_dirty_bitmap_has_successor(b->bitmap)) { bdrv_reclaim_dirty_bitmap(b->bitmap, &error_abort); } else { bdrv_dirty_bitmap_set_busy(b->bitmap, false); } bdrv_release_dirty_bitmap(b->bitmap); } g_slist_free_full(s->bitmaps, g_free); s->bitmaps = NULL; } void dirty_bitmap_mig_cancel_outgoing(void) { dirty_bitmap_do_save_cleanup(&dbm_state.save); } void dirty_bitmap_mig_cancel_incoming(void) { DBMLoadState *s = &dbm_state.load; qemu_mutex_lock(&s->lock); cancel_incoming_locked(s); qemu_mutex_unlock(&s->lock); } static void dirty_bitmap_load_complete(QEMUFile *f, DBMLoadState *s) { GSList *item; trace_dirty_bitmap_load_complete(); if (s->cancelled) { return; } bdrv_dirty_bitmap_deserialize_finish(s->bitmap); if (bdrv_dirty_bitmap_has_successor(s->bitmap)) { bdrv_reclaim_dirty_bitmap(s->bitmap, &error_abort); } else { bdrv_dirty_bitmap_set_busy(s->bitmap, false); } for (item = s->bitmaps; item; item = g_slist_next(item)) { LoadBitmapState *b = item->data; if (b->bitmap == s->bitmap) { b->migrated = true; if (s->before_vm_start_handled) { s->bitmaps = g_slist_remove(s->bitmaps, b); g_free(b); } break; } } } static int dirty_bitmap_load_bits(QEMUFile *f, DBMLoadState *s) { uint64_t first_byte = qemu_get_be64(f) << BDRV_SECTOR_BITS; uint64_t nr_bytes = (uint64_t)qemu_get_be32(f) << BDRV_SECTOR_BITS; trace_dirty_bitmap_load_bits_enter(first_byte >> BDRV_SECTOR_BITS, nr_bytes >> BDRV_SECTOR_BITS); if (s->flags & DIRTY_BITMAP_MIG_FLAG_ZEROES) { trace_dirty_bitmap_load_bits_zeroes(); if (!s->cancelled) { bdrv_dirty_bitmap_deserialize_zeroes(s->bitmap, first_byte, nr_bytes, false); } } else { size_t ret; g_autofree uint8_t *buf = NULL; uint64_t buf_size = qemu_get_be64(f); uint64_t needed_size; /* * The actual check for buf_size is done a bit later. We can't do it in * cancelled mode as we don't have the bitmap to check the constraints * (so, we allocate a buffer and read prior to the check). On the other * hand, we shouldn't blindly g_malloc the number from the stream. * Actually one chunk should not be larger than CHUNK_SIZE. Let's allow * a bit larger (which means that bitmap migration will fail anyway and * the whole migration will most probably fail soon due to broken * stream). */ if (buf_size > 10 * CHUNK_SIZE) { error_report("Bitmap migration stream buffer allocation request " "is too large"); return -EIO; } buf = g_malloc(buf_size); ret = qemu_get_buffer(f, buf, buf_size); if (ret != buf_size) { error_report("Failed to read bitmap bits"); return -EIO; } if (s->cancelled) { return 0; } needed_size = bdrv_dirty_bitmap_serialization_size(s->bitmap, first_byte, nr_bytes); if (needed_size > buf_size || buf_size > QEMU_ALIGN_UP(needed_size, 4 * sizeof(long)) /* Here used same alignment as in send_bitmap_bits */ ) { error_report("Migrated bitmap granularity doesn't " "match the destination bitmap '%s' granularity", bdrv_dirty_bitmap_name(s->bitmap)); cancel_incoming_locked(s); return 0; } bdrv_dirty_bitmap_deserialize_part(s->bitmap, buf, first_byte, nr_bytes, false); } return 0; } static int dirty_bitmap_load_header(QEMUFile *f, DBMLoadState *s, GHashTable *alias_map) { GHashTable *bitmap_alias_map = NULL; Error *local_err = NULL; bool nothing; s->flags = qemu_get_bitmap_flags(f); trace_dirty_bitmap_load_header(s->flags); nothing = s->flags == (s->flags & DIRTY_BITMAP_MIG_FLAG_EOS); if (s->flags & DIRTY_BITMAP_MIG_FLAG_DEVICE_NAME) { if (!qemu_get_counted_string(f, s->node_alias)) { error_report("Unable to read node alias string"); return -EINVAL; } if (!s->cancelled) { if (alias_map) { const AliasMapInnerNode *amin; amin = g_hash_table_lookup(alias_map, s->node_alias); if (!amin) { error_setg(&local_err, "Error: Unknown node alias '%s'", s->node_alias); s->bs = NULL; } else { bitmap_alias_map = amin->subtree; s->bs = bdrv_lookup_bs(NULL, amin->string, &local_err); } } else { s->bs = bdrv_lookup_bs(s->node_alias, s->node_alias, &local_err); } if (!s->bs) { error_report_err(local_err); cancel_incoming_locked(s); } } } else if (s->bs) { if (alias_map) { const AliasMapInnerNode *amin; /* Must be present in the map, or s->bs would not be set */ amin = g_hash_table_lookup(alias_map, s->node_alias); assert(amin != NULL); bitmap_alias_map = amin->subtree; } } else if (!nothing && !s->cancelled) { error_report("Error: block device name is not set"); cancel_incoming_locked(s); } assert(nothing || s->cancelled || !!alias_map == !!bitmap_alias_map); if (s->flags & DIRTY_BITMAP_MIG_FLAG_BITMAP_NAME) { const char *bitmap_name; if (!qemu_get_counted_string(f, s->bitmap_alias)) { error_report("Unable to read bitmap alias string"); return -EINVAL; } bitmap_name = s->bitmap_alias; if (!s->cancelled && bitmap_alias_map) { BitmapMigrationBitmapAlias *bmap_inner; bmap_inner = g_hash_table_lookup(bitmap_alias_map, s->bitmap_alias); if (!bmap_inner) { error_report("Error: Unknown bitmap alias '%s' on node " "'%s' (alias '%s')", s->bitmap_alias, s->bs->node_name, s->node_alias); cancel_incoming_locked(s); } else { bitmap_name = bmap_inner->name; } s->bmap_inner = bmap_inner; } if (!s->cancelled) { g_strlcpy(s->bitmap_name, bitmap_name, sizeof(s->bitmap_name)); s->bitmap = bdrv_find_dirty_bitmap(s->bs, s->bitmap_name); /* * bitmap may be NULL here, it wouldn't be an error if it is the * first occurrence of the bitmap */ if (!s->bitmap && !(s->flags & DIRTY_BITMAP_MIG_FLAG_START)) { error_report("Error: unknown dirty bitmap " "'%s' for block device '%s'", s->bitmap_name, s->bs->node_name); cancel_incoming_locked(s); } } } else if (!s->bitmap && !nothing && !s->cancelled) { error_report("Error: block device name is not set"); cancel_incoming_locked(s); } return 0; } /* * dirty_bitmap_load * * Load sequence of dirty bitmap chunks. Return error only on fatal io stream * violations. On other errors just cancel bitmaps incoming migration and return * 0. * * Note, than when incoming bitmap migration is canceled, we still must read all * our chunks (and just ignore them), to not affect other migration objects. */ static int dirty_bitmap_load(QEMUFile *f, void *opaque, int version_id) { GHashTable *alias_map = NULL; const MigrationParameters *mig_params = &migrate_get_current()->parameters; DBMLoadState *s = &((DBMState *)opaque)->load; int ret = 0; trace_dirty_bitmap_load_enter(); if (version_id != 1) { QEMU_LOCK_GUARD(&s->lock); cancel_incoming_locked(s); return -EINVAL; } if (mig_params->has_block_bitmap_mapping) { alias_map = construct_alias_map(mig_params->block_bitmap_mapping, false, &error_abort); } do { QEMU_LOCK_GUARD(&s->lock); ret = dirty_bitmap_load_header(f, s, alias_map); if (ret < 0) { cancel_incoming_locked(s); goto fail; } if (s->flags & DIRTY_BITMAP_MIG_FLAG_START) { ret = dirty_bitmap_load_start(f, s); } else if (s->flags & DIRTY_BITMAP_MIG_FLAG_COMPLETE) { dirty_bitmap_load_complete(f, s); } else if (s->flags & DIRTY_BITMAP_MIG_FLAG_BITS) { ret = dirty_bitmap_load_bits(f, s); } if (!ret) { ret = qemu_file_get_error(f); } if (ret) { cancel_incoming_locked(s); goto fail; } } while (!(s->flags & DIRTY_BITMAP_MIG_FLAG_EOS)); trace_dirty_bitmap_load_success(); ret = 0; fail: if (alias_map) { g_hash_table_destroy(alias_map); } return ret; } static int dirty_bitmap_save_setup(QEMUFile *f, void *opaque) { DBMSaveState *s = &((DBMState *)opaque)->save; SaveBitmapState *dbms = NULL; qemu_mutex_lock_iothread(); if (init_dirty_bitmap_migration(s) < 0) { qemu_mutex_unlock_iothread(); return -1; } QSIMPLEQ_FOREACH(dbms, &s->dbms_list, entry) { send_bitmap_start(f, s, dbms); } qemu_put_bitmap_flags(f, DIRTY_BITMAP_MIG_FLAG_EOS); qemu_mutex_unlock_iothread(); return 0; } static bool dirty_bitmap_is_active(void *opaque) { DBMSaveState *s = &((DBMState *)opaque)->save; return migrate_dirty_bitmaps() && !s->no_bitmaps; } static bool dirty_bitmap_is_active_iterate(void *opaque) { return dirty_bitmap_is_active(opaque) && !runstate_is_running(); } static bool dirty_bitmap_has_postcopy(void *opaque) { return true; } static SaveVMHandlers savevm_dirty_bitmap_handlers = { .save_setup = dirty_bitmap_save_setup, .save_live_complete_postcopy = dirty_bitmap_save_complete, .save_live_complete_precopy = dirty_bitmap_save_complete, .has_postcopy = dirty_bitmap_has_postcopy, .state_pending_exact = dirty_bitmap_state_pending, .state_pending_estimate = dirty_bitmap_state_pending, .save_live_iterate = dirty_bitmap_save_iterate, .is_active_iterate = dirty_bitmap_is_active_iterate, .load_state = dirty_bitmap_load, .save_cleanup = dirty_bitmap_save_cleanup, .is_active = dirty_bitmap_is_active, }; void dirty_bitmap_mig_init(void) { QSIMPLEQ_INIT(&dbm_state.save.dbms_list); qemu_mutex_init(&dbm_state.load.lock); register_savevm_live("dirty-bitmap", 0, 1, &savevm_dirty_bitmap_handlers, &dbm_state); }