qemu/migration/block-dirty-bitmap.c

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/*
* Block dirty bitmap postcopy migration
*
* Copyright IBM, Corp. 2009
* Copyright (c) 2016-2017 Virtuozzo International GmbH. All rights reserved.
*
* Authors:
* Liran Schour <lirans@il.ibm.com>
* Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
*
* 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 name size ] \ flags & DEVICE_NAME
* [ n bytes: node name ] /
* [ 1 byte: bitmap name size ] \ flags & BITMAP_NAME
* [ n bytes: bitmap name ] /
*
* # 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 "sysemu/block-backend.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 "sysemu/sysemu.h"
#include "qemu/cutils.h"
#include "qapi/error.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 elder versions, no it is ignored */
#define DIRTY_BITMAP_MIG_START_FLAG_RESERVED_MASK 0xf8
typedef struct DirtyBitmapMigBitmapState {
/* Written during setup phase. */
BlockDriverState *bs;
const char *node_name;
BdrvDirtyBitmap *bitmap;
uint64_t total_sectors;
uint64_t sectors_per_chunk;
QSIMPLEQ_ENTRY(DirtyBitmapMigBitmapState) entry;
uint8_t flags;
/* For bulk phase. */
bool bulk_completed;
uint64_t cur_sector;
} DirtyBitmapMigBitmapState;
typedef struct DirtyBitmapMigState {
QSIMPLEQ_HEAD(, DirtyBitmapMigBitmapState) dbms_list;
bool bulk_completed;
bool no_bitmaps;
/* for send_bitmap_bits() */
BlockDriverState *prev_bs;
BdrvDirtyBitmap *prev_bitmap;
} DirtyBitmapMigState;
typedef struct DirtyBitmapLoadState {
uint32_t flags;
char node_name[256];
char bitmap_name[256];
BlockDriverState *bs;
BdrvDirtyBitmap *bitmap;
} DirtyBitmapLoadState;
static DirtyBitmapMigState dirty_bitmap_mig_state;
typedef struct DirtyBitmapLoadBitmapState {
BlockDriverState *bs;
BdrvDirtyBitmap *bitmap;
bool migrated;
} DirtyBitmapLoadBitmapState;
static GSList *enabled_bitmaps;
QemuMutex finish_lock;
void init_dirty_bitmap_incoming_migration(void)
{
qemu_mutex_init(&finish_lock);
}
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 do not send flags more than one byte */
assert(!(flags & (0xffffff00 | DIRTY_BITMAP_MIG_EXTRA_FLAGS)));
qemu_put_byte(f, flags);
}
static void send_bitmap_header(QEMUFile *f, DirtyBitmapMigBitmapState *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 != dirty_bitmap_mig_state.prev_bs) {
dirty_bitmap_mig_state.prev_bs = bs;
flags |= DIRTY_BITMAP_MIG_FLAG_DEVICE_NAME;
}
if (bitmap != dirty_bitmap_mig_state.prev_bitmap) {
dirty_bitmap_mig_state.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_name);
}
if (flags & DIRTY_BITMAP_MIG_FLAG_BITMAP_NAME) {
qemu_put_counted_string(f, bdrv_dirty_bitmap_name(bitmap));
}
}
static void send_bitmap_start(QEMUFile *f, DirtyBitmapMigBitmapState *dbms)
{
send_bitmap_header(f, 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, DirtyBitmapMigBitmapState *dbms)
{
send_bitmap_header(f, dbms, DIRTY_BITMAP_MIG_FLAG_COMPLETE);
}
static void send_bitmap_bits(QEMUFile *f, DirtyBitmapMigBitmapState *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, 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_mig_cleanup(void)
{
DirtyBitmapMigBitmapState *dbms;
while ((dbms = QSIMPLEQ_FIRST(&dirty_bitmap_mig_state.dbms_list)) != NULL) {
QSIMPLEQ_REMOVE_HEAD(&dirty_bitmap_mig_state.dbms_list, entry);
bdrv_dirty_bitmap_set_busy(dbms->bitmap, false);
bdrv_unref(dbms->bs);
g_free(dbms);
}
}
/* Called with iothread lock taken. */
static int init_dirty_bitmap_migration(void)
{
BlockDriverState *bs;
BdrvDirtyBitmap *bitmap;
DirtyBitmapMigBitmapState *dbms;
BdrvNextIterator it;
dirty_bitmap_mig_state.bulk_completed = false;
dirty_bitmap_mig_state.prev_bs = NULL;
dirty_bitmap_mig_state.prev_bitmap = NULL;
dirty_bitmap_mig_state.no_bitmaps = false;
for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
const char *drive_name = bdrv_get_device_or_node_name(bs);
/* skip automatically inserted nodes */
while (bs && bs->drv && bs->implicit) {
bs = backing_bs(bs);
}
for (bitmap = bdrv_dirty_bitmap_next(bs, NULL); bitmap;
bitmap = bdrv_dirty_bitmap_next(bs, bitmap))
{
if (!bdrv_dirty_bitmap_name(bitmap)) {
continue;
}
if (drive_name == NULL) {
error_report("Found bitmap '%s' in unnamed node %p. It can't "
"be migrated", bdrv_dirty_bitmap_name(bitmap), bs);
goto fail;
}
if (bdrv_dirty_bitmap_busy(bitmap)) {
error_report("Can't migrate a bitmap that is in use by another operation: '%s'",
bdrv_dirty_bitmap_name(bitmap));
goto fail;
}
dirty-bitmaps: clean-up bitmaps loading and migration logic This patch aims to bring the following behavior: 1. We don't load bitmaps, when started in inactive mode. It's the case of incoming migration. In this case we wait for bitmaps migration through migration channel (if 'dirty-bitmaps' capability is enabled) or for invalidation (to load bitmaps from the image). 2. We don't remove persistent bitmaps on inactivation. Instead, we only remove bitmaps after storing. This is the only way to restore bitmaps, if we decided to resume source after [failed] migration with 'dirty-bitmaps' capability enabled (which means, that bitmaps were not stored). 3. We load bitmaps on open and any invalidation, it's ok for all cases: - normal open - migration target invalidation with dirty-bitmaps capability (bitmaps are migrating through migration channel, the are not stored, so they should have IN_USE flag set and will be skipped when loading. However, it would fail if bitmaps are read-only[1]) - migration target invalidation without dirty-bitmaps capability (normal load of the bitmaps, if migrated with shared storage) - source invalidation with dirty-bitmaps capability (skip because IN_USE) - source invalidation without dirty-bitmaps capability (bitmaps were dropped, reload them) [1]: to accurately handle this, migration of read-only bitmaps is explicitly forbidden in this patch. New mechanism for not storing bitmaps when migrate with dirty-bitmaps capability is introduced: migration filed in BdrvDirtyBitmap. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: John Snow <jsnow@redhat.com>
2018-10-30 04:23:17 +08:00
if (bdrv_dirty_bitmap_readonly(bitmap)) {
error_report("Can't migrate read-only dirty bitmap: '%s",
bdrv_dirty_bitmap_name(bitmap));
goto fail;
}
bdrv_ref(bs);
bdrv_dirty_bitmap_set_busy(bitmap, true);
dbms = g_new0(DirtyBitmapMigBitmapState, 1);
dbms->bs = bs;
dbms->node_name = drive_name;
dbms->bitmap = bitmap;
dbms->total_sectors = bdrv_nb_sectors(bs);
dbms->sectors_per_chunk = CHUNK_SIZE * 8 *
bdrv_dirty_bitmap_granularity(bitmap) >> BDRV_SECTOR_BITS;
if (bdrv_dirty_bitmap_enabled(bitmap)) {
dbms->flags |= DIRTY_BITMAP_MIG_START_FLAG_ENABLED;
}
if (bdrv_dirty_bitmap_get_persistance(bitmap)) {
dbms->flags |= DIRTY_BITMAP_MIG_START_FLAG_PERSISTENT;
}
QSIMPLEQ_INSERT_TAIL(&dirty_bitmap_mig_state.dbms_list,
dbms, entry);
}
}
dirty-bitmaps: clean-up bitmaps loading and migration logic This patch aims to bring the following behavior: 1. We don't load bitmaps, when started in inactive mode. It's the case of incoming migration. In this case we wait for bitmaps migration through migration channel (if 'dirty-bitmaps' capability is enabled) or for invalidation (to load bitmaps from the image). 2. We don't remove persistent bitmaps on inactivation. Instead, we only remove bitmaps after storing. This is the only way to restore bitmaps, if we decided to resume source after [failed] migration with 'dirty-bitmaps' capability enabled (which means, that bitmaps were not stored). 3. We load bitmaps on open and any invalidation, it's ok for all cases: - normal open - migration target invalidation with dirty-bitmaps capability (bitmaps are migrating through migration channel, the are not stored, so they should have IN_USE flag set and will be skipped when loading. However, it would fail if bitmaps are read-only[1]) - migration target invalidation without dirty-bitmaps capability (normal load of the bitmaps, if migrated with shared storage) - source invalidation with dirty-bitmaps capability (skip because IN_USE) - source invalidation without dirty-bitmaps capability (bitmaps were dropped, reload them) [1]: to accurately handle this, migration of read-only bitmaps is explicitly forbidden in this patch. New mechanism for not storing bitmaps when migrate with dirty-bitmaps capability is introduced: migration filed in BdrvDirtyBitmap. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: John Snow <jsnow@redhat.com>
2018-10-30 04:23:17 +08:00
/* unset migration flags here, to not roll back it */
QSIMPLEQ_FOREACH(dbms, &dirty_bitmap_mig_state.dbms_list, entry) {
dirty-bitmaps: clean-up bitmaps loading and migration logic This patch aims to bring the following behavior: 1. We don't load bitmaps, when started in inactive mode. It's the case of incoming migration. In this case we wait for bitmaps migration through migration channel (if 'dirty-bitmaps' capability is enabled) or for invalidation (to load bitmaps from the image). 2. We don't remove persistent bitmaps on inactivation. Instead, we only remove bitmaps after storing. This is the only way to restore bitmaps, if we decided to resume source after [failed] migration with 'dirty-bitmaps' capability enabled (which means, that bitmaps were not stored). 3. We load bitmaps on open and any invalidation, it's ok for all cases: - normal open - migration target invalidation with dirty-bitmaps capability (bitmaps are migrating through migration channel, the are not stored, so they should have IN_USE flag set and will be skipped when loading. However, it would fail if bitmaps are read-only[1]) - migration target invalidation without dirty-bitmaps capability (normal load of the bitmaps, if migrated with shared storage) - source invalidation with dirty-bitmaps capability (skip because IN_USE) - source invalidation without dirty-bitmaps capability (bitmaps were dropped, reload them) [1]: to accurately handle this, migration of read-only bitmaps is explicitly forbidden in this patch. New mechanism for not storing bitmaps when migrate with dirty-bitmaps capability is introduced: migration filed in BdrvDirtyBitmap. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: John Snow <jsnow@redhat.com>
2018-10-30 04:23:17 +08:00
bdrv_dirty_bitmap_set_migration(dbms->bitmap, true);
}
if (QSIMPLEQ_EMPTY(&dirty_bitmap_mig_state.dbms_list)) {
dirty_bitmap_mig_state.no_bitmaps = true;
}
return 0;
fail:
dirty_bitmap_mig_cleanup();
return -1;
}
/* Called with no lock taken. */
static void bulk_phase_send_chunk(QEMUFile *f, DirtyBitmapMigBitmapState *dbms)
{
uint32_t nr_sectors = MIN(dbms->total_sectors - dbms->cur_sector,
dbms->sectors_per_chunk);
send_bitmap_bits(f, 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, bool limit)
{
DirtyBitmapMigBitmapState *dbms;
QSIMPLEQ_FOREACH(dbms, &dirty_bitmap_mig_state.dbms_list, entry) {
while (!dbms->bulk_completed) {
bulk_phase_send_chunk(f, dbms);
if (limit && qemu_file_rate_limit(f)) {
return;
}
}
}
dirty_bitmap_mig_state.bulk_completed = true;
}
/* for SaveVMHandlers */
static void dirty_bitmap_save_cleanup(void *opaque)
{
dirty_bitmap_mig_cleanup();
}
static int dirty_bitmap_save_iterate(QEMUFile *f, void *opaque)
{
trace_dirty_bitmap_save_iterate(migration_in_postcopy());
if (migration_in_postcopy() && !dirty_bitmap_mig_state.bulk_completed) {
bulk_phase(f, true);
}
qemu_put_bitmap_flags(f, DIRTY_BITMAP_MIG_FLAG_EOS);
return dirty_bitmap_mig_state.bulk_completed;
}
/* Called with iothread lock taken. */
static int dirty_bitmap_save_complete(QEMUFile *f, void *opaque)
{
DirtyBitmapMigBitmapState *dbms;
trace_dirty_bitmap_save_complete_enter();
if (!dirty_bitmap_mig_state.bulk_completed) {
bulk_phase(f, false);
}
QSIMPLEQ_FOREACH(dbms, &dirty_bitmap_mig_state.dbms_list, entry) {
send_bitmap_complete(f, dbms);
}
qemu_put_bitmap_flags(f, DIRTY_BITMAP_MIG_FLAG_EOS);
trace_dirty_bitmap_save_complete_finish();
dirty_bitmap_mig_cleanup();
return 0;
}
static void dirty_bitmap_save_pending(QEMUFile *f, void *opaque,
uint64_t max_size,
uint64_t *res_precopy_only,
uint64_t *res_compatible,
uint64_t *res_postcopy_only)
{
DirtyBitmapMigBitmapState *dbms;
uint64_t pending = 0;
qemu_mutex_lock_iothread();
QSIMPLEQ_FOREACH(dbms, &dirty_bitmap_mig_state.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_save_pending(pending, max_size);
*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, DirtyBitmapLoadState *s)
{
Error *local_err = NULL;
uint32_t granularity = qemu_get_be32(f);
uint8_t flags = qemu_get_byte(f);
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 (flags & DIRTY_BITMAP_MIG_START_FLAG_PERSISTENT) {
bdrv_dirty_bitmap_set_persistance(s->bitmap, true);
}
bdrv_disable_dirty_bitmap(s->bitmap);
if (flags & DIRTY_BITMAP_MIG_START_FLAG_ENABLED) {
DirtyBitmapLoadBitmapState *b;
bdrv_dirty_bitmap_create_successor(s->bs, s->bitmap, &local_err);
if (local_err) {
error_report_err(local_err);
return -EINVAL;
}
b = g_new(DirtyBitmapLoadBitmapState, 1);
b->bs = s->bs;
b->bitmap = s->bitmap;
b->migrated = false;
enabled_bitmaps = g_slist_prepend(enabled_bitmaps, b);
}
return 0;
}
void dirty_bitmap_mig_before_vm_start(void)
{
GSList *item;
qemu_mutex_lock(&finish_lock);
for (item = enabled_bitmaps; item; item = g_slist_next(item)) {
DirtyBitmapLoadBitmapState *b = item->data;
if (b->migrated) {
bdrv_enable_dirty_bitmap_locked(b->bitmap);
} else {
bdrv_dirty_bitmap_enable_successor(b->bitmap);
}
g_free(b);
}
g_slist_free(enabled_bitmaps);
enabled_bitmaps = NULL;
qemu_mutex_unlock(&finish_lock);
}
static void dirty_bitmap_load_complete(QEMUFile *f, DirtyBitmapLoadState *s)
{
GSList *item;
trace_dirty_bitmap_load_complete();
bdrv_dirty_bitmap_deserialize_finish(s->bitmap);
qemu_mutex_lock(&finish_lock);
for (item = enabled_bitmaps; item; item = g_slist_next(item)) {
DirtyBitmapLoadBitmapState *b = item->data;
if (b->bitmap == s->bitmap) {
b->migrated = true;
break;
}
}
if (bdrv_dirty_bitmap_has_successor(s->bitmap)) {
bdrv_dirty_bitmap_lock(s->bitmap);
if (enabled_bitmaps == NULL) {
/* in postcopy */
bdrv_reclaim_dirty_bitmap_locked(s->bs, s->bitmap, &error_abort);
bdrv_enable_dirty_bitmap_locked(s->bitmap);
} else {
/* target not started, successor must be empty */
int64_t count = bdrv_get_dirty_count(s->bitmap);
BdrvDirtyBitmap *ret = bdrv_reclaim_dirty_bitmap_locked(s->bs,
s->bitmap,
NULL);
/* bdrv_reclaim_dirty_bitmap can fail only on no successor (it
* must be) or on merge fail, but merge can't fail when second
* bitmap is empty
*/
assert(ret == s->bitmap &&
count == bdrv_get_dirty_count(s->bitmap));
}
bdrv_dirty_bitmap_unlock(s->bitmap);
}
qemu_mutex_unlock(&finish_lock);
}
static int dirty_bitmap_load_bits(QEMUFile *f, DirtyBitmapLoadState *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();
bdrv_dirty_bitmap_deserialize_zeroes(s->bitmap, first_byte, nr_bytes,
false);
} else {
size_t ret;
uint8_t *buf;
uint64_t buf_size = qemu_get_be64(f);
uint64_t 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));
return -EINVAL;
}
buf = g_malloc(buf_size);
ret = qemu_get_buffer(f, buf, buf_size);
if (ret != buf_size) {
error_report("Failed to read bitmap bits");
g_free(buf);
return -EIO;
}
bdrv_dirty_bitmap_deserialize_part(s->bitmap, buf, first_byte, nr_bytes,
false);
g_free(buf);
}
return 0;
}
static int dirty_bitmap_load_header(QEMUFile *f, DirtyBitmapLoadState *s)
{
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_name)) {
error_report("Unable to read node name string");
return -EINVAL;
}
s->bs = bdrv_lookup_bs(s->node_name, s->node_name, &local_err);
if (!s->bs) {
error_report_err(local_err);
return -EINVAL;
}
} else if (!s->bs && !nothing) {
error_report("Error: block device name is not set");
return -EINVAL;
}
if (s->flags & DIRTY_BITMAP_MIG_FLAG_BITMAP_NAME) {
if (!qemu_get_counted_string(f, s->bitmap_name)) {
error_report("Unable to read bitmap name string");
return -EINVAL;
}
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->node_name);
return -EINVAL;
}
} else if (!s->bitmap && !nothing) {
error_report("Error: block device name is not set");
return -EINVAL;
}
return 0;
}
static int dirty_bitmap_load(QEMUFile *f, void *opaque, int version_id)
{
static DirtyBitmapLoadState s;
int ret = 0;
trace_dirty_bitmap_load_enter();
if (version_id != 1) {
return -EINVAL;
}
do {
ret = dirty_bitmap_load_header(f, &s);
if (ret < 0) {
return ret;
}
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) {
return ret;
}
} while (!(s.flags & DIRTY_BITMAP_MIG_FLAG_EOS));
trace_dirty_bitmap_load_success();
return 0;
}
static int dirty_bitmap_save_setup(QEMUFile *f, void *opaque)
{
DirtyBitmapMigBitmapState *dbms = NULL;
if (init_dirty_bitmap_migration() < 0) {
return -1;
}
QSIMPLEQ_FOREACH(dbms, &dirty_bitmap_mig_state.dbms_list, entry) {
send_bitmap_start(f, dbms);
}
qemu_put_bitmap_flags(f, DIRTY_BITMAP_MIG_FLAG_EOS);
return 0;
}
static bool dirty_bitmap_is_active(void *opaque)
{
return migrate_dirty_bitmaps() && !dirty_bitmap_mig_state.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,
.save_live_pending = dirty_bitmap_save_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(&dirty_bitmap_mig_state.dbms_list);
register_savevm_live(NULL, "dirty-bitmap", 0, 1,
&savevm_dirty_bitmap_handlers,
&dirty_bitmap_mig_state);
}