#include "qemu-common.h"

#include "block_int.h"

#include "hw/hw.h"

#include "qemu-queue.h"

#include "qemu-timer.h"

#include "block-migration.h"

#include "migration.h"

#include "blockdev.h"

#include <assert.h>

#define BLOCK_SIZE (BDRV_SECTORS_PER_DIRTY_CHUNK << BDRV_SECTOR_BITS)

#define BLK_MIG_FLAG_DEVICE_BLOCK 0x01

#define BLK_MIG_FLAG_EOS 0x02

#define BLK_MIG_FLAG_PROGRESS 0x04

#define MAX_IS_ALLOCATED_SEARCH 65536

#ifdef DEBUG_BLK_MIGRATION

#define DPRINTF(fmt, ...) \

do { printf("blk_migration: " fmt, ## __VA_ARGS__); } while (0)

#define DPRINTF(fmt, ...) \

do { } while (0)

typedef struct BlkMigDevState {

BlockDriverState *bs;

int bulk_completed;

int shared_base;

int64_t cur_sector;

int64_t cur_dirty;

int64_t completed_sectors;

int64_t total_sectors;

int64_t dirty;

QSIMPLEQ_ENTRY(BlkMigDevState) entry;

unsigned long *aio_bitmap;

} BlkMigDevState;

typedef struct BlkMigBlock {

uint8_t *buf;

BlkMigDevState *bmds;

int64_t sector;

int nr_sectors;

struct iovec iov;

QEMUIOVector qiov;

BlockDriverAIOCB *aiocb;

int ret;

QSIMPLEQ_ENTRY(BlkMigBlock) entry;

} BlkMigBlock;

typedef struct BlkMigState {

int blk_enable;

int shared_base;

QSIMPLEQ_HEAD(bmds_list, BlkMigDevState) bmds_list;

QSIMPLEQ_HEAD(blk_list, BlkMigBlock) blk_list;

int submitted;

int read_done;

int transferred;

int64_t total_sector_sum;

int prev_progress;

int bulk_completed;

long double total_time;

long double prev_time_offset;

int reads;

} BlkMigState;

static BlkMigState block_mig_state;

static void blk_send(QEMUFile *f, BlkMigBlock * blk)

{

int len;

/* sector number and flags */

qemu_put_be64(f, (blk->sector << BDRV_SECTOR_BITS)

| BLK_MIG_FLAG_DEVICE_BLOCK);

/* device name */

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);

}

int blk_mig_active(void)

{

return !QSIMPLEQ_EMPTY(&block_mig_state.bmds_list);

}

uint64_t blk_mig_bytes_transferred(void)

{

BlkMigDevState *bmds;

uint64_t sum = 0;

QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {

sum += bmds->completed_sectors;

}

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;

}

static inline long double compute_read_bwidth(void)

{

assert(block_mig_state.total_time != 0);

return (block_mig_state.reads / block_mig_state.total_time) * BLOCK_SIZE;

}

static int bmds_aio_inflight(BlkMigDevState *bmds, int64_t sector)

{

int64_t chunk = sector / (int64_t)BDRV_SECTORS_PER_DIRTY_CHUNK;

if ((sector << BDRV_SECTOR_BITS) < bdrv_getlength(bmds->bs)) {

return !!(bmds->aio_bitmap[chunk / (sizeof(unsigned long) * 8)] &

(1UL << (chunk % (sizeof(unsigned long) * 8))));

} else {

return 0;

}

}

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)

{

BlockDriverState *bs = bmds->bs;

int64_t bitmap_size;

bitmap_size = (bdrv_getlength(bs) >> BDRV_SECTOR_BITS) +

BDRV_SECTORS_PER_DIRTY_CHUNK * 8 - 1;

bitmap_size /= BDRV_SECTORS_PER_DIRTY_CHUNK * 8;

bmds->aio_bitmap = g_malloc0(bitmap_size);

}

static void blk_mig_read_cb(void *opaque, int ret)

{

long double curr_time = qemu_get_clock_ns(rt_clock);

BlkMigBlock *blk = opaque;

blk->ret = ret;

block_mig_state.reads++;

block_mig_state.total_time += (curr_time - block_mig_state.prev_time_offset);

block_mig_state.prev_time_offset = curr_time;

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);

}

static int mig_save_device_bulk(QEMUFile *f, BlkMigDevState *bmds)

{

int64_t total_sectors = bmds->total_sectors;

int64_t cur_sector = bmds->cur_sector;

BlockDriverState *bs = bmds->bs;

BlkMigBlock *blk;

int nr_sectors;

if (bmds->shared_base) {

while (cur_sector < total_sectors &&

!bdrv_is_allocated(bs, cur_sector, MAX_IS_ALLOCATED_SEARCH,

&nr_sectors)) {

cur_sector += nr_sectors;

}

}

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_malloc(sizeof(BlkMigBlock));

blk->buf = g_malloc(BLOCK_SIZE);

blk->bmds = bmds;

blk->sector = cur_sector;

blk->nr_sectors = nr_sectors;

blk->iov.iov_base = blk->buf;

blk->iov.iov_len = nr_sectors * BDRV_SECTOR_SIZE;

qemu_iovec_init_external(&blk->qiov, &blk->iov, 1);

if (block_mig_state.submitted == 0) {

block_mig_state.prev_time_offset = qemu_get_clock_ns(rt_clock);

}

blk->aiocb = bdrv_aio_readv(bs, cur_sector, &blk->qiov,

nr_sectors, blk_mig_read_cb, blk);

block_mig_state.submitted++;

bdrv_reset_dirty(bs, cur_sector, nr_sectors);

bmds->cur_sector = cur_sector + nr_sectors;

return (bmds->cur_sector >= total_sectors);

}

static void set_dirty_tracking(int enable)

{

BlkMigDevState *bmds;

QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {

bdrv_set_dirty_tracking(bmds->bs, enable);

}

}

static void init_blk_migration_it(void *opaque, BlockDriverState *bs)

{

BlkMigDevState *bmds;

int64_t sectors;

if (!bdrv_is_read_only(bs)) {

sectors = bdrv_getlength(bs) >> BDRV_SECTOR_BITS;

if (sectors <= 0) {

return;

}

bmds = g_malloc0(sizeof(BlkMigDevState));

bmds->bs = bs;

bmds->bulk_completed = 0;

bmds->total_sectors = sectors;

bmds->completed_sectors = 0;

bmds->shared_base = block_mig_state.shared_base;

alloc_aio_bitmap(bmds);

drive_get_ref(drive_get_by_blockdev(bs));

bdrv_set_in_use(bs, 1);

block_mig_state.total_sector_sum += sectors;

if (bmds->shared_base) {

DPRINTF("Start migration for %s with shared base image\n",

bs->device_name);

} else {

DPRINTF("Start full migration for %s\n", bs->device_name);

}

QSIMPLEQ_INSERT_TAIL(&block_mig_state.bmds_list, bmds, entry);

}

}

static void init_blk_migration(QEMUFile *f)

{

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.total_time = 0;

block_mig_state.reads = 0;

bdrv_iterate(init_blk_migration_it, NULL);

}

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;

}

}

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;) {

if (bmds_aio_inflight(bmds, sector)) {

bdrv_drain_all();

}

if (bdrv_get_dirty(bmds->bs, sector)) {

if (total_sectors - sector < BDRV_SECTORS_PER_DIRTY_CHUNK) {

nr_sectors = total_sectors - sector;

} else {

nr_sectors = BDRV_SECTORS_PER_DIRTY_CHUNK;

}

blk = g_malloc(sizeof(BlkMigBlock));

blk->buf = g_malloc(BLOCK_SIZE);

blk->bmds = bmds;

blk->sector = sector;

blk->nr_sectors = nr_sectors;

if (is_async) {

blk->iov.iov_base = blk->buf;

blk->iov.iov_len = nr_sectors * BDRV_SECTOR_SIZE;

qemu_iovec_init_external(&blk->qiov, &blk->iov, 1);

if (block_mig_state.submitted == 0) {

block_mig_state.prev_time_offset = qemu_get_clock_ns(rt_clock);

}

blk->aiocb = bdrv_aio_readv(bmds->bs, sector, &blk->qiov,

nr_sectors, blk_mig_read_cb, blk);

block_mig_state.submitted++;

bmds_set_aio_inflight(bmds, sector, nr_sectors, 1);

} else {

ret = bdrv_read(bmds->bs, sector, blk->buf, nr_sectors);

if (ret < 0) {

goto error;

}

blk_send(f, blk);

g_free(blk->buf);

g_free(blk);

}

bdrv_reset_dirty(bmds->bs, sector, nr_sectors);

break;

}

sector += BDRV_SECTORS_PER_DIRTY_CHUNK;

bmds->cur_dirty = sector;

}

return (bmds->cur_dirty >= bmds->total_sectors);

error:

DPRINTF("Error reading sector %" PRId64 "\n", sector);

g_free(blk->buf);

g_free(blk);

return ret;

}

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) {

ret = mig_save_device_dirty(f, bmds, is_async);

if (ret <= 0) {

break;

}

}

return ret;

}

static int flush_blks(QEMUFile *f)

{

BlkMigBlock *blk;

int ret = 0;

DPRINTF("%s Enter submitted %d read_done %d transferred %d\n",

__FUNCTION__, block_mig_state.submitted, block_mig_state.read_done,

block_mig_state.transferred);

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;

}

blk_send(f, blk);

QSIMPLEQ_REMOVE_HEAD(&block_mig_state.blk_list, entry);

g_free(blk->buf);

g_free(blk);

block_mig_state.read_done--;

block_mig_state.transferred++;

assert(block_mig_state.read_done >= 0);

}

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 ret;

}

static int64_t get_remaining_dirty(void)

{

BlkMigDevState *bmds;

int64_t dirty = 0;

QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {

dirty += bdrv_get_dirty_count(bmds->bs);

}

return dirty * BLOCK_SIZE;

}

static int is_stage2_completed(void)

{

int64_t remaining_dirty;

long double bwidth;

if (block_mig_state.bulk_completed == 1) {

remaining_dirty = get_remaining_dirty();

if (remaining_dirty == 0) {

return 1;

}

bwidth = compute_read_bwidth();

if ((remaining_dirty / bwidth) <=

migrate_max_downtime()) {

/* finish stage2 because we think that we can finish remaining work

return 1;

}

}

return 0;

}

static void blk_mig_cleanup(void)

{

BlkMigDevState *bmds;

BlkMigBlock *blk;

bdrv_drain_all();

set_dirty_tracking(0);

while ((bmds = QSIMPLEQ_FIRST(&block_mig_state.bmds_list)) != NULL) {

QSIMPLEQ_REMOVE_HEAD(&block_mig_state.bmds_list, entry);

bdrv_set_in_use(bmds->bs, 0);

drive_put_ref(drive_get_by_blockdev(bmds->bs));

g_free(bmds->aio_bitmap);

g_free(bmds);

}

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);

}

}

static void block_migration_cancel(void *opaque)

{

blk_mig_cleanup();

}

static int block_save_setup(QEMUFile *f, void *opaque)

{

int ret;

DPRINTF("Enter save live setup submitted %d transferred %d\n",

block_mig_state.submitted, block_mig_state.transferred);

init_blk_migration(f);

/* start track dirty blocks */

set_dirty_tracking(1);

ret = flush_blks(f);

if (ret) {

blk_mig_cleanup();

return ret;

}

blk_mig_reset_dirty_cursor();

qemu_put_be64(f, BLK_MIG_FLAG_EOS);

return 0;

}

static int block_save_iterate(QEMUFile *f, void *opaque)

{

int ret;

DPRINTF("Enter save live iterate submitted %d transferred %d\n",

block_mig_state.submitted, block_mig_state.transferred);

ret = flush_blks(f);

if (ret) {

blk_mig_cleanup();

return ret;

}

blk_mig_reset_dirty_cursor();

/* control the rate of transfer */

while ((block_mig_state.submitted +

block_mig_state.read_done) * BLOCK_SIZE <

qemu_file_get_rate_limit(f)) {

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;

}

} else {

ret = blk_mig_save_dirty_block(f, 1);

if (ret != 0) {

/* no more dirty blocks */

break;

}

}

}

if (ret) {

blk_mig_cleanup();

return ret;

}

ret = flush_blks(f);

if (ret) {

blk_mig_cleanup();

return ret;

}

qemu_put_be64(f, BLK_MIG_FLAG_EOS);

return is_stage2_completed();

}

static int block_save_complete(QEMUFile *f, void *opaque)

{

int ret;

DPRINTF("Enter save live complete submitted %d transferred %d\n",

block_mig_state.submitted, block_mig_state.transferred);

ret = flush_blks(f);

if (ret) {

blk_mig_cleanup();

return ret;

}

blk_mig_reset_dirty_cursor();

/* we know for sure that save bulk is completed and

assert(block_mig_state.submitted == 0);

do {

ret = blk_mig_save_dirty_block(f, 0);

} while (ret == 0);

blk_mig_cleanup();

if (ret) {

return ret;

}

/* report completion */

qemu_put_be64(f, (100 << BDRV_SECTOR_BITS) | BLK_MIG_FLAG_PROGRESS);

DPRINTF("Block migration completed\n");

qemu_put_be64(f, BLK_MIG_FLAG_EOS);

return 0;

}

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;

BlockDriverState *bs, *bs_prev = NULL;

uint8_t *buf;

int64_t total_sectors = 0;

int nr_sectors;

int ret;

do {

addr = qemu_get_be64(f);

flags = addr & ~BDRV_SECTOR_MASK;

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';

bs = bdrv_find(device_name);

if (!bs) {

fprintf(stderr, "Error unknown block device %s\n",

device_name);

return -EINVAL;

}

if (bs != bs_prev) {

bs_prev = bs;

total_sectors = bdrv_getlength(bs) >> BDRV_SECTOR_BITS;

if (total_sectors <= 0) {

error_report("Error getting length of block device %s",

device_name);

return -EINVAL;

}

}

if (total_sectors - addr < BDRV_SECTORS_PER_DIRTY_CHUNK) {

nr_sectors = total_sectors - addr;

} else {

nr_sectors = BDRV_SECTORS_PER_DIRTY_CHUNK;

}

buf = g_malloc(BLOCK_SIZE);

qemu_get_buffer(f, buf, BLOCK_SIZE);

ret = bdrv_write(bs, addr, buf, nr_sectors);

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 flags\n");

return -EINVAL;

}

ret = qemu_file_get_error(f);

if (ret != 0) {

return ret;

}

} while (!(flags & BLK_MIG_FLAG_EOS));

return 0;

}

static void block_set_params(const MigrationParams *params, void *opaque)

{

block_mig_state.blk_enable = params->blk;

block_mig_state.shared_base = params->shared;

/* shared base means that blk_enable = 1 */

block_mig_state.blk_enable |= params->shared;

}

static bool block_is_active(void *opaque)

{

return block_mig_state.blk_enable == 1;

}

SaveVMHandlers savevm_block_handlers = {

.set_params = block_set_params,

.save_live_setup = block_save_setup,

.save_live_iterate = block_save_iterate,

.save_live_complete = block_save_complete,

.load_state = block_load,

.cancel = block_migration_cancel,

.is_active = block_is_active,

};

void blk_mig_init(void)

{

QSIMPLEQ_INIT(&block_mig_state.bmds_list);

QSIMPLEQ_INIT(&block_mig_state.blk_list);

register_savevm_live(NULL, "block", 0, 1, &savevm_block_handlers,

&block_mig_state);

}