/* * QEMU live block migration * * Copyright IBM, Corp. 2009 * * Authors: * Liran Schour * * This work is licensed under the terms of the GNU GPL, version 2. See * the COPYING file in the top-level directory. * * Contributions after 2012-01-13 are licensed under the terms of the * GNU GPL, version 2 or (at your option) any later version. */ #include "qemu/osdep.h" #include "qapi/error.h" #include "qemu/error-report.h" #include "qemu/main-loop.h" #include "qemu/cutils.h" #include "qemu/queue.h" #include "block.h" #include "block/dirty-bitmap.h" #include "migration/misc.h" #include "migration.h" #include "migration/register.h" #include "qemu-file.h" #include "migration/vmstate.h" #include "sysemu/block-backend.h" #include "trace.h" #define BLK_MIG_BLOCK_SIZE (1ULL << 20) #define BDRV_SECTORS_PER_DIRTY_CHUNK (BLK_MIG_BLOCK_SIZE >> BDRV_SECTOR_BITS) #define BLK_MIG_FLAG_DEVICE_BLOCK 0x01 #define BLK_MIG_FLAG_EOS 0x02 #define BLK_MIG_FLAG_PROGRESS 0x04 #define BLK_MIG_FLAG_ZERO_BLOCK 0x08 #define MAX_IS_ALLOCATED_SEARCH (65536 * BDRV_SECTOR_SIZE) #define MAX_IO_BUFFERS 512 #define MAX_PARALLEL_IO 16 /* #define DEBUG_BLK_MIGRATION */ #ifdef DEBUG_BLK_MIGRATION #define DPRINTF(fmt, ...) \ do { printf("blk_migration: " fmt, ## __VA_ARGS__); } while (0) #else #define DPRINTF(fmt, ...) \ do { } while (0) #endif typedef struct BlkMigDevState { /* Written during setup phase. Can be read without a lock. */ BlockBackend *blk; char *blk_name; int shared_base; int64_t total_sectors; QSIMPLEQ_ENTRY(BlkMigDevState) entry; Error *blocker; /* Only used by migration thread. Does not need a lock. */ int bulk_completed; int64_t cur_sector; int64_t cur_dirty; /* Data in the aio_bitmap is protected by block migration lock. * Allocation and free happen during setup and cleanup respectively. */ unsigned long *aio_bitmap; /* Protected by block migration lock. */ int64_t completed_sectors; /* During migration this is protected by iothread lock / AioContext. * Allocation and free happen during setup and cleanup respectively. */ BdrvDirtyBitmap *dirty_bitmap; } BlkMigDevState; typedef struct BlkMigBlock { /* Only used by migration thread. */ uint8_t *buf; BlkMigDevState *bmds; int64_t sector; int nr_sectors; QEMUIOVector qiov; BlockAIOCB *aiocb; /* Protected by block migration lock. */ int ret; QSIMPLEQ_ENTRY(BlkMigBlock) entry; } BlkMigBlock; typedef struct BlkMigState { QSIMPLEQ_HEAD(, BlkMigDevState) bmds_list; int64_t total_sector_sum; bool zero_blocks; /* Protected by lock. */ QSIMPLEQ_HEAD(, BlkMigBlock) blk_list; int submitted; int read_done; /* Only used by migration thread. Does not need a lock. */ int transferred; int prev_progress; int bulk_completed; /* Lock must be taken _inside_ the iothread lock and any AioContexts. */ QemuMutex lock; } BlkMigState; static BlkMigState block_mig_state; static void blk_mig_lock(void) { qemu_mutex_lock(&block_mig_state.lock); } static void blk_mig_unlock(void) { qemu_mutex_unlock(&block_mig_state.lock); } /* Must run outside of the iothread lock during the bulk phase, * or the VM will stall. */ static void blk_send(QEMUFile *f, BlkMigBlock * blk) { int len; uint64_t flags = BLK_MIG_FLAG_DEVICE_BLOCK; if (block_mig_state.zero_blocks && buffer_is_zero(blk->buf, BLK_MIG_BLOCK_SIZE)) { flags |= BLK_MIG_FLAG_ZERO_BLOCK; } /* sector number and flags */ qemu_put_be64(f, (blk->sector << BDRV_SECTOR_BITS) | flags); /* device name */ len = strlen(blk->bmds->blk_name); qemu_put_byte(f, len); qemu_put_buffer(f, (uint8_t *) blk->bmds->blk_name, len); /* 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 & BLK_MIG_FLAG_ZERO_BLOCK) { qemu_fflush(f); return; } qemu_put_buffer(f, blk->buf, BLK_MIG_BLOCK_SIZE); } int blk_mig_active(void) { return !QSIMPLEQ_EMPTY(&block_mig_state.bmds_list); } int blk_mig_bulk_active(void) { return blk_mig_active() && !block_mig_state.bulk_completed; } uint64_t blk_mig_bytes_transferred(void) { BlkMigDevState *bmds; uint64_t sum = 0; blk_mig_lock(); QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) { sum += bmds->completed_sectors; } blk_mig_unlock(); return sum << BDRV_SECTOR_BITS; } uint64_t blk_mig_bytes_remaining(void) { return blk_mig_bytes_total() - blk_mig_bytes_transferred(); } uint64_t blk_mig_bytes_total(void) { BlkMigDevState *bmds; uint64_t sum = 0; QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) { sum += bmds->total_sectors; } return sum << BDRV_SECTOR_BITS; } /* Called with migration lock held. */ static int bmds_aio_inflight(BlkMigDevState *bmds, int64_t sector) { int64_t chunk = sector / (int64_t)BDRV_SECTORS_PER_DIRTY_CHUNK; if (sector < blk_nb_sectors(bmds->blk)) { return !!(bmds->aio_bitmap[chunk / (sizeof(unsigned long) * 8)] & (1UL << (chunk % (sizeof(unsigned long) * 8)))); } else { return 0; } } /* Called with migration lock held. */ static void bmds_set_aio_inflight(BlkMigDevState *bmds, int64_t sector_num, int nb_sectors, int set) { int64_t start, end; unsigned long val, idx, bit; start = sector_num / BDRV_SECTORS_PER_DIRTY_CHUNK; end = (sector_num + nb_sectors - 1) / BDRV_SECTORS_PER_DIRTY_CHUNK; for (; start <= end; start++) { idx = start / (sizeof(unsigned long) * 8); bit = start % (sizeof(unsigned long) * 8); val = bmds->aio_bitmap[idx]; if (set) { val |= 1UL << bit; } else { val &= ~(1UL << bit); } bmds->aio_bitmap[idx] = val; } } static void alloc_aio_bitmap(BlkMigDevState *bmds) { BlockBackend *bb = bmds->blk; int64_t bitmap_size; bitmap_size = blk_nb_sectors(bb) + BDRV_SECTORS_PER_DIRTY_CHUNK * 8 - 1; bitmap_size /= BDRV_SECTORS_PER_DIRTY_CHUNK * 8; bmds->aio_bitmap = g_malloc0(bitmap_size); } /* Never hold migration lock when yielding to the main loop! */ static void blk_mig_read_cb(void *opaque, int ret) { BlkMigBlock *blk = opaque; blk_mig_lock(); blk->ret = ret; QSIMPLEQ_INSERT_TAIL(&block_mig_state.blk_list, blk, entry); bmds_set_aio_inflight(blk->bmds, blk->sector, blk->nr_sectors, 0); block_mig_state.submitted--; block_mig_state.read_done++; assert(block_mig_state.submitted >= 0); blk_mig_unlock(); } /* Called with no lock taken. */ static int mig_save_device_bulk(QEMUFile *f, BlkMigDevState *bmds) { int64_t total_sectors = bmds->total_sectors; int64_t cur_sector = bmds->cur_sector; BlockBackend *bb = bmds->blk; BlkMigBlock *blk; int nr_sectors; int64_t count; if (bmds->shared_base) { qemu_mutex_lock_iothread(); aio_context_acquire(blk_get_aio_context(bb)); /* Skip unallocated sectors; intentionally treats failure or * partial sector as an allocated sector */ while (cur_sector < total_sectors && !bdrv_is_allocated(blk_bs(bb), cur_sector * BDRV_SECTOR_SIZE, MAX_IS_ALLOCATED_SEARCH, &count)) { if (count < BDRV_SECTOR_SIZE) { break; } cur_sector += count >> BDRV_SECTOR_BITS; } aio_context_release(blk_get_aio_context(bb)); qemu_mutex_unlock_iothread(); } if (cur_sector >= total_sectors) { bmds->cur_sector = bmds->completed_sectors = total_sectors; return 1; } bmds->completed_sectors = cur_sector; cur_sector &= ~((int64_t)BDRV_SECTORS_PER_DIRTY_CHUNK - 1); /* we are going to transfer a full block even if it is not allocated */ nr_sectors = BDRV_SECTORS_PER_DIRTY_CHUNK; if (total_sectors - cur_sector < BDRV_SECTORS_PER_DIRTY_CHUNK) { nr_sectors = total_sectors - cur_sector; } blk = g_new(BlkMigBlock, 1); blk->buf = g_malloc(BLK_MIG_BLOCK_SIZE); blk->bmds = bmds; blk->sector = cur_sector; blk->nr_sectors = nr_sectors; qemu_iovec_init_buf(&blk->qiov, blk->buf, nr_sectors * BDRV_SECTOR_SIZE); blk_mig_lock(); block_mig_state.submitted++; blk_mig_unlock(); /* We do not know if bs is under the main thread (and thus does * not acquire the AioContext when doing AIO) or rather under * dataplane. Thus acquire both the iothread mutex and the * AioContext. * * This is ugly and will disappear when we make bdrv_* thread-safe, * without the need to acquire the AioContext. */ qemu_mutex_lock_iothread(); aio_context_acquire(blk_get_aio_context(bmds->blk)); bdrv_reset_dirty_bitmap(bmds->dirty_bitmap, cur_sector * BDRV_SECTOR_SIZE, nr_sectors * BDRV_SECTOR_SIZE); blk->aiocb = blk_aio_preadv(bb, cur_sector * BDRV_SECTOR_SIZE, &blk->qiov, 0, blk_mig_read_cb, blk); aio_context_release(blk_get_aio_context(bmds->blk)); qemu_mutex_unlock_iothread(); bmds->cur_sector = cur_sector + nr_sectors; return (bmds->cur_sector >= total_sectors); } /* Called with iothread lock taken. */ static int set_dirty_tracking(void) { BlkMigDevState *bmds; int ret; QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) { bmds->dirty_bitmap = bdrv_create_dirty_bitmap(blk_bs(bmds->blk), BLK_MIG_BLOCK_SIZE, NULL, NULL); if (!bmds->dirty_bitmap) { ret = -errno; goto fail; } } return 0; fail: QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) { if (bmds->dirty_bitmap) { bdrv_release_dirty_bitmap(bmds->dirty_bitmap); } } return ret; } /* Called with iothread lock taken. */ static void unset_dirty_tracking(void) { BlkMigDevState *bmds; QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) { bdrv_release_dirty_bitmap(bmds->dirty_bitmap); } } static int init_blk_migration(QEMUFile *f) { BlockDriverState *bs; BlkMigDevState *bmds; int64_t sectors; BdrvNextIterator it; int i, num_bs = 0; struct { BlkMigDevState *bmds; BlockDriverState *bs; } *bmds_bs; Error *local_err = NULL; int ret; block_mig_state.submitted = 0; block_mig_state.read_done = 0; block_mig_state.transferred = 0; block_mig_state.total_sector_sum = 0; block_mig_state.prev_progress = -1; block_mig_state.bulk_completed = 0; block_mig_state.zero_blocks = migrate_zero_blocks(); for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { num_bs++; } bmds_bs = g_malloc0(num_bs * sizeof(*bmds_bs)); for (i = 0, bs = bdrv_first(&it); bs; bs = bdrv_next(&it), i++) { if (bdrv_is_read_only(bs)) { continue; } sectors = bdrv_nb_sectors(bs); if (sectors <= 0) { ret = sectors; bdrv_next_cleanup(&it); goto out; } bmds = g_new0(BlkMigDevState, 1); bmds->blk = blk_new(qemu_get_aio_context(), BLK_PERM_CONSISTENT_READ, BLK_PERM_ALL); bmds->blk_name = g_strdup(bdrv_get_device_name(bs)); bmds->bulk_completed = 0; bmds->total_sectors = sectors; bmds->completed_sectors = 0; bmds->shared_base = migrate_use_block_incremental(); assert(i < num_bs); bmds_bs[i].bmds = bmds; bmds_bs[i].bs = bs; block_mig_state.total_sector_sum += sectors; if (bmds->shared_base) { trace_migration_block_init_shared(bdrv_get_device_name(bs)); } else { trace_migration_block_init_full(bdrv_get_device_name(bs)); } QSIMPLEQ_INSERT_TAIL(&block_mig_state.bmds_list, bmds, entry); } /* Can only insert new BDSes now because doing so while iterating block * devices may end up in a deadlock (iterating the new BDSes, too). */ for (i = 0; i < num_bs; i++) { BlkMigDevState *bmds = bmds_bs[i].bmds; BlockDriverState *bs = bmds_bs[i].bs; if (bmds) { ret = blk_insert_bs(bmds->blk, bs, &local_err); if (ret < 0) { error_report_err(local_err); goto out; } alloc_aio_bitmap(bmds); error_setg(&bmds->blocker, "block device is in use by migration"); bdrv_op_block_all(bs, bmds->blocker); } } ret = 0; out: g_free(bmds_bs); return ret; } /* Called with no lock taken. */ static int blk_mig_save_bulked_block(QEMUFile *f) { int64_t completed_sector_sum = 0; BlkMigDevState *bmds; int progress; int ret = 0; QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) { if (bmds->bulk_completed == 0) { if (mig_save_device_bulk(f, bmds) == 1) { /* completed bulk section for this device */ bmds->bulk_completed = 1; } completed_sector_sum += bmds->completed_sectors; ret = 1; break; } else { completed_sector_sum += bmds->completed_sectors; } } if (block_mig_state.total_sector_sum != 0) { progress = completed_sector_sum * 100 / block_mig_state.total_sector_sum; } else { progress = 100; } if (progress != block_mig_state.prev_progress) { block_mig_state.prev_progress = progress; qemu_put_be64(f, (progress << BDRV_SECTOR_BITS) | BLK_MIG_FLAG_PROGRESS); DPRINTF("Completed %d %%\r", progress); } return ret; } static void blk_mig_reset_dirty_cursor(void) { BlkMigDevState *bmds; QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) { bmds->cur_dirty = 0; } } /* Called with iothread lock and AioContext taken. */ static int mig_save_device_dirty(QEMUFile *f, BlkMigDevState *bmds, int is_async) { BlkMigBlock *blk; int64_t total_sectors = bmds->total_sectors; int64_t sector; int nr_sectors; int ret = -EIO; for (sector = bmds->cur_dirty; sector < bmds->total_sectors;) { blk_mig_lock(); if (bmds_aio_inflight(bmds, sector)) { blk_mig_unlock(); blk_drain(bmds->blk); } else { blk_mig_unlock(); } bdrv_dirty_bitmap_lock(bmds->dirty_bitmap); if (bdrv_dirty_bitmap_get_locked(bmds->dirty_bitmap, sector * BDRV_SECTOR_SIZE)) { if (total_sectors - sector < BDRV_SECTORS_PER_DIRTY_CHUNK) { nr_sectors = total_sectors - sector; } else { nr_sectors = BDRV_SECTORS_PER_DIRTY_CHUNK; } bdrv_reset_dirty_bitmap_locked(bmds->dirty_bitmap, sector * BDRV_SECTOR_SIZE, nr_sectors * BDRV_SECTOR_SIZE); bdrv_dirty_bitmap_unlock(bmds->dirty_bitmap); blk = g_new(BlkMigBlock, 1); blk->buf = g_malloc(BLK_MIG_BLOCK_SIZE); blk->bmds = bmds; blk->sector = sector; blk->nr_sectors = nr_sectors; if (is_async) { qemu_iovec_init_buf(&blk->qiov, blk->buf, nr_sectors * BDRV_SECTOR_SIZE); blk->aiocb = blk_aio_preadv(bmds->blk, sector * BDRV_SECTOR_SIZE, &blk->qiov, 0, blk_mig_read_cb, blk); blk_mig_lock(); block_mig_state.submitted++; bmds_set_aio_inflight(bmds, sector, nr_sectors, 1); blk_mig_unlock(); } else { ret = blk_pread(bmds->blk, sector * BDRV_SECTOR_SIZE, nr_sectors * BDRV_SECTOR_SIZE, blk->buf, 0); if (ret < 0) { goto error; } blk_send(f, blk); g_free(blk->buf); g_free(blk); } sector += nr_sectors; bmds->cur_dirty = sector; break; } bdrv_dirty_bitmap_unlock(bmds->dirty_bitmap); sector += BDRV_SECTORS_PER_DIRTY_CHUNK; bmds->cur_dirty = sector; } return (bmds->cur_dirty >= bmds->total_sectors); error: trace_migration_block_save_device_dirty(sector); g_free(blk->buf); g_free(blk); return ret; } /* Called with iothread lock taken. * * return value: * 0: too much data for max_downtime * 1: few enough data for max_downtime */ static int blk_mig_save_dirty_block(QEMUFile *f, int is_async) { BlkMigDevState *bmds; int ret = 1; QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) { aio_context_acquire(blk_get_aio_context(bmds->blk)); ret = mig_save_device_dirty(f, bmds, is_async); aio_context_release(blk_get_aio_context(bmds->blk)); if (ret <= 0) { break; } } return ret; } /* Called with no locks taken. */ static int flush_blks(QEMUFile *f) { BlkMigBlock *blk; int ret = 0; trace_migration_block_flush_blks("Enter", block_mig_state.submitted, block_mig_state.read_done, block_mig_state.transferred); blk_mig_lock(); while ((blk = QSIMPLEQ_FIRST(&block_mig_state.blk_list)) != NULL) { if (qemu_file_rate_limit(f)) { break; } if (blk->ret < 0) { ret = blk->ret; break; } QSIMPLEQ_REMOVE_HEAD(&block_mig_state.blk_list, entry); blk_mig_unlock(); blk_send(f, blk); blk_mig_lock(); g_free(blk->buf); g_free(blk); block_mig_state.read_done--; block_mig_state.transferred++; assert(block_mig_state.read_done >= 0); } blk_mig_unlock(); trace_migration_block_flush_blks("Exit", block_mig_state.submitted, block_mig_state.read_done, block_mig_state.transferred); return ret; } /* Called with iothread lock taken. */ static int64_t get_remaining_dirty(void) { BlkMigDevState *bmds; int64_t dirty = 0; QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) { aio_context_acquire(blk_get_aio_context(bmds->blk)); dirty += bdrv_get_dirty_count(bmds->dirty_bitmap); aio_context_release(blk_get_aio_context(bmds->blk)); } return dirty; } /* Called with iothread lock taken. */ static void block_migration_cleanup_bmds(void) { BlkMigDevState *bmds; AioContext *ctx; unset_dirty_tracking(); while ((bmds = QSIMPLEQ_FIRST(&block_mig_state.bmds_list)) != NULL) { QSIMPLEQ_REMOVE_HEAD(&block_mig_state.bmds_list, entry); bdrv_op_unblock_all(blk_bs(bmds->blk), bmds->blocker); error_free(bmds->blocker); /* Save ctx, because bmds->blk can disappear during blk_unref. */ ctx = blk_get_aio_context(bmds->blk); aio_context_acquire(ctx); blk_unref(bmds->blk); aio_context_release(ctx); g_free(bmds->blk_name); g_free(bmds->aio_bitmap); g_free(bmds); } } /* Called with iothread lock taken. */ static void block_migration_cleanup(void *opaque) { BlkMigBlock *blk; bdrv_drain_all(); block_migration_cleanup_bmds(); blk_mig_lock(); while ((blk = QSIMPLEQ_FIRST(&block_mig_state.blk_list)) != NULL) { QSIMPLEQ_REMOVE_HEAD(&block_mig_state.blk_list, entry); g_free(blk->buf); g_free(blk); } blk_mig_unlock(); } static int block_save_setup(QEMUFile *f, void *opaque) { int ret; trace_migration_block_save("setup", block_mig_state.submitted, block_mig_state.transferred); qemu_mutex_lock_iothread(); ret = init_blk_migration(f); if (ret < 0) { qemu_mutex_unlock_iothread(); return ret; } /* start track dirty blocks */ ret = set_dirty_tracking(); qemu_mutex_unlock_iothread(); if (ret) { return ret; } ret = flush_blks(f); blk_mig_reset_dirty_cursor(); qemu_put_be64(f, BLK_MIG_FLAG_EOS); return ret; } static int block_save_iterate(QEMUFile *f, void *opaque) { int ret; int64_t last_bytes = qemu_file_total_transferred(f); int64_t delta_bytes; trace_migration_block_save("iterate", block_mig_state.submitted, block_mig_state.transferred); ret = flush_blks(f); if (ret) { return ret; } blk_mig_reset_dirty_cursor(); /* control the rate of transfer */ blk_mig_lock(); while (block_mig_state.read_done * BLK_MIG_BLOCK_SIZE < qemu_file_get_rate_limit(f) && block_mig_state.submitted < MAX_PARALLEL_IO && (block_mig_state.submitted + block_mig_state.read_done) < MAX_IO_BUFFERS) { blk_mig_unlock(); if (block_mig_state.bulk_completed == 0) { /* first finish the bulk phase */ if (blk_mig_save_bulked_block(f) == 0) { /* finished saving bulk on all devices */ block_mig_state.bulk_completed = 1; } ret = 0; } else { /* Always called with iothread lock taken for * simplicity, block_save_complete also calls it. */ qemu_mutex_lock_iothread(); ret = blk_mig_save_dirty_block(f, 1); qemu_mutex_unlock_iothread(); } if (ret < 0) { return ret; } blk_mig_lock(); if (ret != 0) { /* no more dirty blocks */ break; } } blk_mig_unlock(); ret = flush_blks(f); if (ret) { return ret; } qemu_put_be64(f, BLK_MIG_FLAG_EOS); delta_bytes = qemu_file_total_transferred(f) - last_bytes; if (delta_bytes > 0) { return 1; } else if (delta_bytes < 0) { return -1; } else { return 0; } } /* Called with iothread lock taken. */ static int block_save_complete(QEMUFile *f, void *opaque) { int ret; trace_migration_block_save("complete", block_mig_state.submitted, block_mig_state.transferred); ret = flush_blks(f); if (ret) { return ret; } blk_mig_reset_dirty_cursor(); /* we know for sure that save bulk is completed and all async read completed */ blk_mig_lock(); assert(block_mig_state.submitted == 0); blk_mig_unlock(); do { ret = blk_mig_save_dirty_block(f, 0); if (ret < 0) { return ret; } } while (ret == 0); /* report completion */ qemu_put_be64(f, (100 << BDRV_SECTOR_BITS) | BLK_MIG_FLAG_PROGRESS); trace_migration_block_save_complete(); qemu_put_be64(f, BLK_MIG_FLAG_EOS); /* Make sure that our BlockBackends are gone, so that the block driver * nodes can be inactivated. */ block_migration_cleanup_bmds(); return 0; } static void block_save_pending(QEMUFile *f, void *opaque, uint64_t max_size, uint64_t *res_precopy_only, uint64_t *res_compatible, uint64_t *res_postcopy_only) { /* Estimate pending number of bytes to send */ uint64_t pending; qemu_mutex_lock_iothread(); pending = get_remaining_dirty(); qemu_mutex_unlock_iothread(); blk_mig_lock(); pending += block_mig_state.submitted * BLK_MIG_BLOCK_SIZE + block_mig_state.read_done * BLK_MIG_BLOCK_SIZE; blk_mig_unlock(); /* Report at least one block pending during bulk phase */ if (!pending && !block_mig_state.bulk_completed) { pending = BLK_MIG_BLOCK_SIZE; } trace_migration_block_save_pending(pending); /* We don't do postcopy */ *res_precopy_only += pending; } static int block_load(QEMUFile *f, void *opaque, int version_id) { static int banner_printed; int len, flags; char device_name[256]; int64_t addr; BlockBackend *blk, *blk_prev = NULL; Error *local_err = NULL; uint8_t *buf; int64_t total_sectors = 0; int nr_sectors; int ret; BlockDriverInfo bdi; int cluster_size = BLK_MIG_BLOCK_SIZE; do { addr = qemu_get_be64(f); flags = addr & (BDRV_SECTOR_SIZE - 1); addr >>= BDRV_SECTOR_BITS; if (flags & BLK_MIG_FLAG_DEVICE_BLOCK) { /* get device name */ len = qemu_get_byte(f); qemu_get_buffer(f, (uint8_t *)device_name, len); device_name[len] = '\0'; blk = blk_by_name(device_name); if (!blk) { fprintf(stderr, "Error unknown block device %s\n", device_name); return -EINVAL; } if (blk != blk_prev) { blk_prev = blk; total_sectors = blk_nb_sectors(blk); if (total_sectors <= 0) { error_report("Error getting length of block device %s", device_name); return -EINVAL; } blk_activate(blk, &local_err); if (local_err) { error_report_err(local_err); return -EINVAL; } ret = bdrv_get_info(blk_bs(blk), &bdi); if (ret == 0 && bdi.cluster_size > 0 && bdi.cluster_size <= BLK_MIG_BLOCK_SIZE && BLK_MIG_BLOCK_SIZE % bdi.cluster_size == 0) { cluster_size = bdi.cluster_size; } else { cluster_size = BLK_MIG_BLOCK_SIZE; } } if (total_sectors - addr < BDRV_SECTORS_PER_DIRTY_CHUNK) { nr_sectors = total_sectors - addr; } else { nr_sectors = BDRV_SECTORS_PER_DIRTY_CHUNK; } if (flags & BLK_MIG_FLAG_ZERO_BLOCK) { ret = blk_pwrite_zeroes(blk, addr * BDRV_SECTOR_SIZE, nr_sectors * BDRV_SECTOR_SIZE, BDRV_REQ_MAY_UNMAP); } else { int i; int64_t cur_addr; uint8_t *cur_buf; buf = g_malloc(BLK_MIG_BLOCK_SIZE); qemu_get_buffer(f, buf, BLK_MIG_BLOCK_SIZE); for (i = 0; i < BLK_MIG_BLOCK_SIZE / cluster_size; i++) { cur_addr = addr * BDRV_SECTOR_SIZE + i * cluster_size; cur_buf = buf + i * cluster_size; if ((!block_mig_state.zero_blocks || cluster_size < BLK_MIG_BLOCK_SIZE) && buffer_is_zero(cur_buf, cluster_size)) { ret = blk_pwrite_zeroes(blk, cur_addr, cluster_size, BDRV_REQ_MAY_UNMAP); } else { ret = blk_pwrite(blk, cur_addr, cluster_size, cur_buf, 0); } if (ret < 0) { break; } } g_free(buf); } if (ret < 0) { return ret; } } else if (flags & BLK_MIG_FLAG_PROGRESS) { if (!banner_printed) { printf("Receiving block device images\n"); banner_printed = 1; } printf("Completed %d %%%c", (int)addr, (addr == 100) ? '\n' : '\r'); fflush(stdout); } else if (!(flags & BLK_MIG_FLAG_EOS)) { fprintf(stderr, "Unknown block migration flags: 0x%x\n", flags); return -EINVAL; } ret = qemu_file_get_error(f); if (ret != 0) { return ret; } } while (!(flags & BLK_MIG_FLAG_EOS)); return 0; } static bool block_is_active(void *opaque) { return migrate_use_block(); } static SaveVMHandlers savevm_block_handlers = { .save_setup = block_save_setup, .save_live_iterate = block_save_iterate, .save_live_complete_precopy = block_save_complete, .save_live_pending = block_save_pending, .load_state = block_load, .save_cleanup = block_migration_cleanup, .is_active = block_is_active, }; void blk_mig_init(void) { QSIMPLEQ_INIT(&block_mig_state.bmds_list); QSIMPLEQ_INIT(&block_mig_state.blk_list); qemu_mutex_init(&block_mig_state.lock); register_savevm_live("block", 0, 1, &savevm_block_handlers, &block_mig_state); }