/* * QEMU live block migration * * Copyright IBM, Corp. 2009 * * Authors: * Liran Schour <lirans@il.ibm.com> * * This work is licensed under the terms of the GNU GPL, version 2. See * the COPYING file in the top-level directory. * */ #include "qemu-common.h" #include "block_int.h" #include "hw/hw.h" #include "block-migration.h" #include <assert.h> #include <pthread.h> #define SECTOR_BITS 9 #define SECTOR_SIZE (1 << SECTOR_BITS) #define SECTOR_MASK ~(SECTOR_SIZE - 1); #define BLOCK_SIZE (block_mig_state->sectors_per_block << SECTOR_BITS) #define BLK_MIG_FLAG_DEVICE_BLOCK 0x01 #define BLK_MIG_FLAG_EOS 0x02 #define MAX_IS_ALLOCATED_SEARCH 65536 #define MAX_BLOCKS_READ 10000 #define BLOCKS_READ_CHANGE 100 #define INITIAL_BLOCKS_READ 100 //#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 BlkMigBlock { uint8_t *buf; BlkMigDevState *bmds; int64_t sector; struct iovec iov; QEMUIOVector qiov; BlockDriverAIOCB *aiocb; int ret; struct BlkMigBlock *next; } BlkMigBlock; typedef struct BlkMigState { int bulk_completed; int blk_enable; int shared_base; int no_dirty; QEMUFile *load_file; BlkMigDevState *bmds_first; int sectors_per_block; BlkMigBlock *first_blk; BlkMigBlock *last_blk; int submitted; int read_done; int transferred; int64_t print_completion; } BlkMigState; static BlkMigState *block_mig_state = NULL; static void blk_mig_read_cb(void *opaque, int ret) { BlkMigBlock *blk = opaque; blk->ret = ret; /* insert at the end */ if(block_mig_state->last_blk == NULL) { block_mig_state->first_blk = blk; block_mig_state->last_blk = blk; } else { block_mig_state->last_blk->next = blk; block_mig_state->last_blk = blk; } block_mig_state->submitted--; block_mig_state->read_done++; assert(block_mig_state->submitted >= 0); return; } static int mig_read_device_bulk(QEMUFile *f, BlkMigDevState *bms) { int nr_sectors; int64_t total_sectors, cur_sector = 0; BlockDriverState *bs = bms->bs; BlkMigBlock *blk; blk = qemu_malloc(sizeof(BlkMigBlock)); blk->buf = qemu_malloc(BLOCK_SIZE); cur_sector = bms->cur_sector; total_sectors = bdrv_getlength(bs) >> SECTOR_BITS; if(bms->shared_base) { while(cur_sector < bms->total_sectors && !bdrv_is_allocated(bms->bs, cur_sector, MAX_IS_ALLOCATED_SEARCH, &nr_sectors)) { cur_sector += nr_sectors; } } if(cur_sector >= total_sectors) { bms->cur_sector = total_sectors; qemu_free(blk->buf); qemu_free(blk); return 1; } if(cur_sector >= block_mig_state->print_completion) { printf("Completed %" PRId64 " %%\r", cur_sector * 100 / total_sectors); fflush(stdout); block_mig_state->print_completion += (block_mig_state->sectors_per_block * 10000); } /* we going to transfder BLOCK_SIZE any way even if it is not allocated */ nr_sectors = block_mig_state->sectors_per_block; cur_sector &= ~((int64_t)block_mig_state->sectors_per_block -1); if(total_sectors - cur_sector < block_mig_state->sectors_per_block) { nr_sectors = (total_sectors - cur_sector); } bms->cur_sector = cur_sector + nr_sectors; blk->sector = cur_sector; blk->bmds = bms; blk->next = NULL; blk->iov.iov_base = blk->buf; blk->iov.iov_len = nr_sectors * SECTOR_SIZE; qemu_iovec_init_external(&blk->qiov, &blk->iov, 1); blk->aiocb = bdrv_aio_readv(bs, cur_sector, &blk->qiov, nr_sectors, blk_mig_read_cb, blk); if(!blk->aiocb) { printf("Error reading sector %" PRId64 "\n", cur_sector); qemu_free(blk->buf); qemu_free(blk); return 0; } bdrv_reset_dirty(bms->bs, cur_sector, nr_sectors); block_mig_state->submitted++; return (bms->cur_sector >= total_sectors); } static int mig_save_device_bulk(QEMUFile *f, BlkMigDevState *bmds) { int len, nr_sectors; int64_t total_sectors = bmds->total_sectors, cur_sector = 0; uint8_t *tmp_buf = NULL; BlockDriverState *bs = bmds->bs; tmp_buf = qemu_malloc(BLOCK_SIZE); cur_sector = bmds->cur_sector; if(bmds->shared_base) { while(cur_sector < bmds->total_sectors && !bdrv_is_allocated(bmds->bs, cur_sector, MAX_IS_ALLOCATED_SEARCH, &nr_sectors)) { cur_sector += nr_sectors; } } if(cur_sector >= total_sectors) { bmds->cur_sector = total_sectors; qemu_free(tmp_buf); return 1; } if(cur_sector >= block_mig_state->print_completion) { printf("Completed %" PRId64 " %%\r", cur_sector * 100 / total_sectors); fflush(stdout); block_mig_state->print_completion += (block_mig_state->sectors_per_block * 10000); } cur_sector &= ~((int64_t)block_mig_state->sectors_per_block -1); /* we going to transfer BLOCK_SIZE any way even if it is not allocated */ nr_sectors = block_mig_state->sectors_per_block; if(total_sectors - cur_sector < block_mig_state->sectors_per_block) { nr_sectors = (total_sectors - cur_sector); } if(bdrv_read(bs, cur_sector, tmp_buf, nr_sectors) < 0) { printf("Error reading sector %" PRId64 "\n", cur_sector); } bdrv_reset_dirty(bs, cur_sector, nr_sectors); /* Device name */ qemu_put_be64(f,(cur_sector << SECTOR_BITS) | BLK_MIG_FLAG_DEVICE_BLOCK); len = strlen(bs->device_name); qemu_put_byte(f, len); qemu_put_buffer(f, (uint8_t *)bs->device_name, len); qemu_put_buffer(f, tmp_buf, BLOCK_SIZE); bmds->cur_sector = cur_sector + block_mig_state->sectors_per_block; qemu_free(tmp_buf); return (bmds->cur_sector >= total_sectors); } static void send_blk(QEMUFile *f, BlkMigBlock * blk) { int len; /* Device name */ qemu_put_be64(f,(blk->sector << SECTOR_BITS) | BLK_MIG_FLAG_DEVICE_BLOCK); len = strlen(blk->bmds->bs->device_name); qemu_put_byte(f, len); qemu_put_buffer(f, (uint8_t *)blk->bmds->bs->device_name, len); qemu_put_buffer(f, blk->buf, BLOCK_SIZE); return; } static void blk_mig_save_dev_info(QEMUFile *f, BlkMigDevState *bmds) { } static void set_dirty_tracking(int enable) { BlkMigDevState *bmds; for(bmds = block_mig_state->bmds_first; bmds != NULL; bmds = bmds->next) { bdrv_set_dirty_tracking(bmds->bs,enable); } return; } static void init_blk_migration(QEMUFile *f) { BlkMigDevState **pbmds, *bmds; BlockDriverState *bs; for (bs = bdrv_first; bs != NULL; bs = bs->next) { if(bs->type == BDRV_TYPE_HD) { bmds = qemu_mallocz(sizeof(BlkMigDevState)); bmds->bs = bs; bmds->bulk_completed = 0; bmds->total_sectors = bdrv_getlength(bs) >> SECTOR_BITS; bmds->shared_base = block_mig_state->shared_base; if(bmds->shared_base) { printf("Start migration for %s with shared base image\n", bs->device_name); } else { printf("Start full migration for %s\n", bs->device_name); } /* insert at the end */ pbmds = &block_mig_state->bmds_first; while (*pbmds != NULL) pbmds = &(*pbmds)->next; *pbmds = bmds; blk_mig_save_dev_info(f, bmds); } } block_mig_state->sectors_per_block = bdrv_get_sectors_per_chunk(); return; } static int blk_mig_save_bulked_block(QEMUFile *f, int is_async) { BlkMigDevState *bmds; for (bmds = block_mig_state->bmds_first; bmds != NULL; bmds = bmds->next) { if(bmds->bulk_completed == 0) { if(is_async) { if(mig_read_device_bulk(f, bmds) == 1) { /* completed bulk section for this device */ bmds->bulk_completed = 1; } } else { if(mig_save_device_bulk(f,bmds) == 1) { /* completed bulk section for this device */ bmds->bulk_completed = 1; } } return 1; } } /* we reached here means bulk is completed */ block_mig_state->bulk_completed = 1; return 0; } #define MAX_NUM_BLOCKS 4 static void blk_mig_save_dirty_blocks(QEMUFile *f) { BlkMigDevState *bmds; uint8_t buf[BLOCK_SIZE]; int64_t sector; int len; for(bmds = block_mig_state->bmds_first; bmds != NULL; bmds = bmds->next) { for(sector = 0; sector < bmds->cur_sector;) { if(bdrv_get_dirty(bmds->bs,sector)) { if(bdrv_read(bmds->bs, sector, buf, block_mig_state->sectors_per_block) < 0) { } /* device name */ qemu_put_be64(f,(sector << SECTOR_BITS) | BLK_MIG_FLAG_DEVICE_BLOCK); len = strlen(bmds->bs->device_name); qemu_put_byte(f, len); qemu_put_buffer(f, (uint8_t *)bmds->bs->device_name, len); qemu_put_buffer(f, buf, (block_mig_state->sectors_per_block * SECTOR_SIZE)); bdrv_reset_dirty(bmds->bs, sector, block_mig_state->sectors_per_block); sector += block_mig_state->sectors_per_block; } else { /* sector is clean */ sector += block_mig_state->sectors_per_block; } } } return; } static void flush_blks(QEMUFile* f) { BlkMigBlock *blk, *tmp; dprintf("%s Enter submitted %d read_done %d transfered\n", __FUNCTION__, submitted, read_done, transfered); for(blk = block_mig_state->first_blk; blk != NULL && !qemu_file_rate_limit(f); blk = tmp) { send_blk(f, blk); tmp = blk->next; qemu_free(blk->buf); qemu_free(blk); block_mig_state->read_done--; block_mig_state->transferred++; assert(block_mig_state->read_done >= 0); } block_mig_state->first_blk = blk; if(block_mig_state->first_blk == NULL) { block_mig_state->last_blk = NULL; } dprintf("%s Exit submitted %d read_done %d transferred%d\n", __FUNCTION__, block_mig_state->submitted, block_mig_state->read_done, block_mig_state->transferred); return; } static int is_stage2_completed(void) { BlkMigDevState *bmds; if(block_mig_state->submitted > 0) { return 0; } for (bmds = block_mig_state->bmds_first; bmds != NULL; bmds = bmds->next) { if(bmds->bulk_completed == 0) { return 0; } } return 1; } static int block_save_live(QEMUFile *f, int stage, void *opaque) { int ret = 1; dprintf("Enter save live stage %d submitted %d transferred %d\n", stage, submitted, transferred); if(block_mig_state->blk_enable != 1) { /* no need to migrate storage */ qemu_put_be64(f,BLK_MIG_FLAG_EOS); return 1; } if(stage == 1) { init_blk_migration(f); /* start track dirty blocks */ set_dirty_tracking(1); } flush_blks(f); /* control the rate of transfer */ while ((block_mig_state->submitted + block_mig_state->read_done) * (BLOCK_SIZE) < (qemu_file_get_rate_limit(f))) { ret = blk_mig_save_bulked_block(f, 1); if (ret == 0) /* no more bulk blocks for now*/ break; } flush_blks(f); if(stage == 3) { while(blk_mig_save_bulked_block(f, 0) != 0); blk_mig_save_dirty_blocks(f); /* stop track dirty blocks */ set_dirty_tracking(0);; printf("\nBlock migration completed\n"); } qemu_put_be64(f,BLK_MIG_FLAG_EOS); return ((stage == 2) && is_stage2_completed()); } static int block_load(QEMUFile *f, void *opaque, int version_id) { int len, flags; char device_name[256]; int64_t addr; BlockDriverState *bs; uint8_t *buf; block_mig_state->sectors_per_block = bdrv_get_sectors_per_chunk(); buf = qemu_malloc(BLOCK_SIZE); do { addr = qemu_get_be64(f); flags = addr & ~SECTOR_MASK; addr &= SECTOR_MASK; 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'; bs = bdrv_find(device_name); qemu_get_buffer(f, buf, BLOCK_SIZE); if(bs != NULL) { bdrv_write(bs, (addr >> SECTOR_BITS), buf, block_mig_state->sectors_per_block); } else { printf("Error unknown block device %s\n", device_name); } } else if(flags & BLK_MIG_FLAG_EOS) { } else { printf("Unknown flags\n"); } } while(!(flags & BLK_MIG_FLAG_EOS)); qemu_free(buf); return 0; } static void block_set_params(int blk_enable, int shared_base, void *opaque) { assert(opaque == block_mig_state); block_mig_state->blk_enable = blk_enable; block_mig_state->shared_base = shared_base; /* shared base means that blk_enable = 1 */ block_mig_state->blk_enable |= shared_base; return; } void blk_mig_info(void) { BlockDriverState *bs; for (bs = bdrv_first; bs != NULL; bs = bs->next) { printf("Device %s\n", bs->device_name); if(bs->type == BDRV_TYPE_HD) { printf("device %s format %s\n", bs->device_name, bs->drv->format_name); } } } void blk_mig_init(void) { block_mig_state = qemu_mallocz(sizeof(BlkMigState)); register_savevm_live("block", 0, 1, block_set_params, block_save_live, NULL, block_load, block_mig_state); }