14f1043b4SStefan Hajnoczi /* 24f1043b4SStefan Hajnoczi * Image streaming 34f1043b4SStefan Hajnoczi * 44f1043b4SStefan Hajnoczi * Copyright IBM, Corp. 2011 54f1043b4SStefan Hajnoczi * 64f1043b4SStefan Hajnoczi * Authors: 74f1043b4SStefan Hajnoczi * Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> 84f1043b4SStefan Hajnoczi * 94f1043b4SStefan Hajnoczi * This work is licensed under the terms of the GNU LGPL, version 2 or later. 104f1043b4SStefan Hajnoczi * See the COPYING.LIB file in the top-level directory. 114f1043b4SStefan Hajnoczi * 124f1043b4SStefan Hajnoczi */ 134f1043b4SStefan Hajnoczi 144f1043b4SStefan Hajnoczi #include "trace.h" 154f1043b4SStefan Hajnoczi #include "block_int.h" 164f1043b4SStefan Hajnoczi 174f1043b4SStefan Hajnoczi enum { 184f1043b4SStefan Hajnoczi /* 194f1043b4SStefan Hajnoczi * Size of data buffer for populating the image file. This should be large 204f1043b4SStefan Hajnoczi * enough to process multiple clusters in a single call, so that populating 214f1043b4SStefan Hajnoczi * contiguous regions of the image is efficient. 224f1043b4SStefan Hajnoczi */ 234f1043b4SStefan Hajnoczi STREAM_BUFFER_SIZE = 512 * 1024, /* in bytes */ 244f1043b4SStefan Hajnoczi }; 254f1043b4SStefan Hajnoczi 265094a6c0SStefan Hajnoczi #define SLICE_TIME 100000000ULL /* ns */ 275094a6c0SStefan Hajnoczi 285094a6c0SStefan Hajnoczi typedef struct { 295094a6c0SStefan Hajnoczi int64_t next_slice_time; 305094a6c0SStefan Hajnoczi uint64_t slice_quota; 315094a6c0SStefan Hajnoczi uint64_t dispatched; 325094a6c0SStefan Hajnoczi } RateLimit; 335094a6c0SStefan Hajnoczi 345094a6c0SStefan Hajnoczi static int64_t ratelimit_calculate_delay(RateLimit *limit, uint64_t n) 355094a6c0SStefan Hajnoczi { 365094a6c0SStefan Hajnoczi int64_t delay_ns = 0; 375094a6c0SStefan Hajnoczi int64_t now = qemu_get_clock_ns(rt_clock); 385094a6c0SStefan Hajnoczi 395094a6c0SStefan Hajnoczi if (limit->next_slice_time < now) { 405094a6c0SStefan Hajnoczi limit->next_slice_time = now + SLICE_TIME; 415094a6c0SStefan Hajnoczi limit->dispatched = 0; 425094a6c0SStefan Hajnoczi } 435094a6c0SStefan Hajnoczi if (limit->dispatched + n > limit->slice_quota) { 445094a6c0SStefan Hajnoczi delay_ns = limit->next_slice_time - now; 455094a6c0SStefan Hajnoczi } else { 465094a6c0SStefan Hajnoczi limit->dispatched += n; 475094a6c0SStefan Hajnoczi } 485094a6c0SStefan Hajnoczi return delay_ns; 495094a6c0SStefan Hajnoczi } 505094a6c0SStefan Hajnoczi 515094a6c0SStefan Hajnoczi static void ratelimit_set_speed(RateLimit *limit, uint64_t speed) 525094a6c0SStefan Hajnoczi { 535094a6c0SStefan Hajnoczi limit->slice_quota = speed / (1000000000ULL / SLICE_TIME); 545094a6c0SStefan Hajnoczi } 555094a6c0SStefan Hajnoczi 564f1043b4SStefan Hajnoczi typedef struct StreamBlockJob { 574f1043b4SStefan Hajnoczi BlockJob common; 585094a6c0SStefan Hajnoczi RateLimit limit; 594f1043b4SStefan Hajnoczi BlockDriverState *base; 60*c8c3080fSMarcelo Tosatti char backing_file_id[1024]; 614f1043b4SStefan Hajnoczi } StreamBlockJob; 624f1043b4SStefan Hajnoczi 634f1043b4SStefan Hajnoczi static int coroutine_fn stream_populate(BlockDriverState *bs, 644f1043b4SStefan Hajnoczi int64_t sector_num, int nb_sectors, 654f1043b4SStefan Hajnoczi void *buf) 664f1043b4SStefan Hajnoczi { 674f1043b4SStefan Hajnoczi struct iovec iov = { 684f1043b4SStefan Hajnoczi .iov_base = buf, 694f1043b4SStefan Hajnoczi .iov_len = nb_sectors * BDRV_SECTOR_SIZE, 704f1043b4SStefan Hajnoczi }; 714f1043b4SStefan Hajnoczi QEMUIOVector qiov; 724f1043b4SStefan Hajnoczi 734f1043b4SStefan Hajnoczi qemu_iovec_init_external(&qiov, &iov, 1); 744f1043b4SStefan Hajnoczi 754f1043b4SStefan Hajnoczi /* Copy-on-read the unallocated clusters */ 764f1043b4SStefan Hajnoczi return bdrv_co_copy_on_readv(bs, sector_num, nb_sectors, &qiov); 774f1043b4SStefan Hajnoczi } 784f1043b4SStefan Hajnoczi 79*c8c3080fSMarcelo Tosatti /* 80*c8c3080fSMarcelo Tosatti * Given an image chain: [BASE] -> [INTER1] -> [INTER2] -> [TOP] 81*c8c3080fSMarcelo Tosatti * 82*c8c3080fSMarcelo Tosatti * Return true if the given sector is allocated in top. 83*c8c3080fSMarcelo Tosatti * Return false if the given sector is allocated in intermediate images. 84*c8c3080fSMarcelo Tosatti * Return true otherwise. 85*c8c3080fSMarcelo Tosatti * 86*c8c3080fSMarcelo Tosatti * 'pnum' is set to the number of sectors (including and immediately following 87*c8c3080fSMarcelo Tosatti * the specified sector) that are known to be in the same 88*c8c3080fSMarcelo Tosatti * allocated/unallocated state. 89*c8c3080fSMarcelo Tosatti * 90*c8c3080fSMarcelo Tosatti */ 91*c8c3080fSMarcelo Tosatti static int coroutine_fn is_allocated_base(BlockDriverState *top, 92*c8c3080fSMarcelo Tosatti BlockDriverState *base, 93*c8c3080fSMarcelo Tosatti int64_t sector_num, 94*c8c3080fSMarcelo Tosatti int nb_sectors, int *pnum) 95*c8c3080fSMarcelo Tosatti { 96*c8c3080fSMarcelo Tosatti BlockDriverState *intermediate; 97*c8c3080fSMarcelo Tosatti int ret, n; 98*c8c3080fSMarcelo Tosatti 99*c8c3080fSMarcelo Tosatti ret = bdrv_co_is_allocated(top, sector_num, nb_sectors, &n); 100*c8c3080fSMarcelo Tosatti if (ret) { 101*c8c3080fSMarcelo Tosatti *pnum = n; 102*c8c3080fSMarcelo Tosatti return ret; 103*c8c3080fSMarcelo Tosatti } 104*c8c3080fSMarcelo Tosatti 105*c8c3080fSMarcelo Tosatti /* 106*c8c3080fSMarcelo Tosatti * Is the unallocated chunk [sector_num, n] also 107*c8c3080fSMarcelo Tosatti * unallocated between base and top? 108*c8c3080fSMarcelo Tosatti */ 109*c8c3080fSMarcelo Tosatti intermediate = top->backing_hd; 110*c8c3080fSMarcelo Tosatti 111*c8c3080fSMarcelo Tosatti while (intermediate) { 112*c8c3080fSMarcelo Tosatti int pnum_inter; 113*c8c3080fSMarcelo Tosatti 114*c8c3080fSMarcelo Tosatti /* reached base */ 115*c8c3080fSMarcelo Tosatti if (intermediate == base) { 116*c8c3080fSMarcelo Tosatti *pnum = n; 117*c8c3080fSMarcelo Tosatti return 1; 118*c8c3080fSMarcelo Tosatti } 119*c8c3080fSMarcelo Tosatti ret = bdrv_co_is_allocated(intermediate, sector_num, nb_sectors, 120*c8c3080fSMarcelo Tosatti &pnum_inter); 121*c8c3080fSMarcelo Tosatti if (ret < 0) { 122*c8c3080fSMarcelo Tosatti return ret; 123*c8c3080fSMarcelo Tosatti } else if (ret) { 124*c8c3080fSMarcelo Tosatti *pnum = pnum_inter; 125*c8c3080fSMarcelo Tosatti return 0; 126*c8c3080fSMarcelo Tosatti } 127*c8c3080fSMarcelo Tosatti 128*c8c3080fSMarcelo Tosatti /* 129*c8c3080fSMarcelo Tosatti * [sector_num, nb_sectors] is unallocated on top but intermediate 130*c8c3080fSMarcelo Tosatti * might have 131*c8c3080fSMarcelo Tosatti * 132*c8c3080fSMarcelo Tosatti * [sector_num+x, nr_sectors] allocated. 133*c8c3080fSMarcelo Tosatti */ 134*c8c3080fSMarcelo Tosatti if (n > pnum_inter) { 135*c8c3080fSMarcelo Tosatti n = pnum_inter; 136*c8c3080fSMarcelo Tosatti } 137*c8c3080fSMarcelo Tosatti 138*c8c3080fSMarcelo Tosatti intermediate = intermediate->backing_hd; 139*c8c3080fSMarcelo Tosatti } 140*c8c3080fSMarcelo Tosatti 141*c8c3080fSMarcelo Tosatti return 1; 142*c8c3080fSMarcelo Tosatti } 143*c8c3080fSMarcelo Tosatti 1444f1043b4SStefan Hajnoczi static void coroutine_fn stream_run(void *opaque) 1454f1043b4SStefan Hajnoczi { 1464f1043b4SStefan Hajnoczi StreamBlockJob *s = opaque; 1474f1043b4SStefan Hajnoczi BlockDriverState *bs = s->common.bs; 148*c8c3080fSMarcelo Tosatti BlockDriverState *base = s->base; 1494f1043b4SStefan Hajnoczi int64_t sector_num, end; 1504f1043b4SStefan Hajnoczi int ret = 0; 1514f1043b4SStefan Hajnoczi int n; 1524f1043b4SStefan Hajnoczi void *buf; 1534f1043b4SStefan Hajnoczi 1544f1043b4SStefan Hajnoczi s->common.len = bdrv_getlength(bs); 1554f1043b4SStefan Hajnoczi if (s->common.len < 0) { 1564f1043b4SStefan Hajnoczi block_job_complete(&s->common, s->common.len); 1574f1043b4SStefan Hajnoczi return; 1584f1043b4SStefan Hajnoczi } 1594f1043b4SStefan Hajnoczi 1604f1043b4SStefan Hajnoczi end = s->common.len >> BDRV_SECTOR_BITS; 1614f1043b4SStefan Hajnoczi buf = qemu_blockalign(bs, STREAM_BUFFER_SIZE); 1624f1043b4SStefan Hajnoczi 1634f1043b4SStefan Hajnoczi /* Turn on copy-on-read for the whole block device so that guest read 1644f1043b4SStefan Hajnoczi * requests help us make progress. Only do this when copying the entire 1654f1043b4SStefan Hajnoczi * backing chain since the copy-on-read operation does not take base into 1664f1043b4SStefan Hajnoczi * account. 1674f1043b4SStefan Hajnoczi */ 1684f1043b4SStefan Hajnoczi if (!base) { 1694f1043b4SStefan Hajnoczi bdrv_enable_copy_on_read(bs); 1704f1043b4SStefan Hajnoczi } 1714f1043b4SStefan Hajnoczi 1724f1043b4SStefan Hajnoczi for (sector_num = 0; sector_num < end; sector_num += n) { 1735094a6c0SStefan Hajnoczi retry: 1744f1043b4SStefan Hajnoczi if (block_job_is_cancelled(&s->common)) { 1754f1043b4SStefan Hajnoczi break; 1764f1043b4SStefan Hajnoczi } 1774f1043b4SStefan Hajnoczi 178*c8c3080fSMarcelo Tosatti 179*c8c3080fSMarcelo Tosatti if (base) { 180*c8c3080fSMarcelo Tosatti ret = is_allocated_base(bs, base, sector_num, 1814f1043b4SStefan Hajnoczi STREAM_BUFFER_SIZE / BDRV_SECTOR_SIZE, &n); 182*c8c3080fSMarcelo Tosatti } else { 183*c8c3080fSMarcelo Tosatti ret = bdrv_co_is_allocated(bs, sector_num, 184*c8c3080fSMarcelo Tosatti STREAM_BUFFER_SIZE / BDRV_SECTOR_SIZE, 185*c8c3080fSMarcelo Tosatti &n); 186*c8c3080fSMarcelo Tosatti } 1874f1043b4SStefan Hajnoczi trace_stream_one_iteration(s, sector_num, n, ret); 1884f1043b4SStefan Hajnoczi if (ret == 0) { 1895094a6c0SStefan Hajnoczi if (s->common.speed) { 1905094a6c0SStefan Hajnoczi uint64_t delay_ns = ratelimit_calculate_delay(&s->limit, n); 1915094a6c0SStefan Hajnoczi if (delay_ns > 0) { 1925094a6c0SStefan Hajnoczi co_sleep_ns(rt_clock, delay_ns); 1935094a6c0SStefan Hajnoczi 1945094a6c0SStefan Hajnoczi /* Recheck cancellation and that sectors are unallocated */ 1955094a6c0SStefan Hajnoczi goto retry; 1965094a6c0SStefan Hajnoczi } 1975094a6c0SStefan Hajnoczi } 1984f1043b4SStefan Hajnoczi ret = stream_populate(bs, sector_num, n, buf); 1994f1043b4SStefan Hajnoczi } 2004f1043b4SStefan Hajnoczi if (ret < 0) { 2014f1043b4SStefan Hajnoczi break; 2024f1043b4SStefan Hajnoczi } 203*c8c3080fSMarcelo Tosatti ret = 0; 2044f1043b4SStefan Hajnoczi 2054f1043b4SStefan Hajnoczi /* Publish progress */ 2064f1043b4SStefan Hajnoczi s->common.offset += n * BDRV_SECTOR_SIZE; 2075094a6c0SStefan Hajnoczi 2085094a6c0SStefan Hajnoczi /* Note that even when no rate limit is applied we need to yield 2095094a6c0SStefan Hajnoczi * with no pending I/O here so that qemu_aio_flush() returns. 2105094a6c0SStefan Hajnoczi */ 2115094a6c0SStefan Hajnoczi co_sleep_ns(rt_clock, 0); 2124f1043b4SStefan Hajnoczi } 2134f1043b4SStefan Hajnoczi 2144f1043b4SStefan Hajnoczi if (!base) { 2154f1043b4SStefan Hajnoczi bdrv_disable_copy_on_read(bs); 2164f1043b4SStefan Hajnoczi } 2174f1043b4SStefan Hajnoczi 2184f1043b4SStefan Hajnoczi if (sector_num == end && ret == 0) { 219*c8c3080fSMarcelo Tosatti const char *base_id = NULL; 220*c8c3080fSMarcelo Tosatti if (base) { 221*c8c3080fSMarcelo Tosatti base_id = s->backing_file_id; 222*c8c3080fSMarcelo Tosatti } 223*c8c3080fSMarcelo Tosatti ret = bdrv_change_backing_file(bs, base_id, NULL); 2244f1043b4SStefan Hajnoczi } 2254f1043b4SStefan Hajnoczi 2264f1043b4SStefan Hajnoczi qemu_vfree(buf); 2274f1043b4SStefan Hajnoczi block_job_complete(&s->common, ret); 2284f1043b4SStefan Hajnoczi } 2294f1043b4SStefan Hajnoczi 2305094a6c0SStefan Hajnoczi static int stream_set_speed(BlockJob *job, int64_t value) 2315094a6c0SStefan Hajnoczi { 2325094a6c0SStefan Hajnoczi StreamBlockJob *s = container_of(job, StreamBlockJob, common); 2335094a6c0SStefan Hajnoczi 2345094a6c0SStefan Hajnoczi if (value < 0) { 2355094a6c0SStefan Hajnoczi return -EINVAL; 2365094a6c0SStefan Hajnoczi } 2375094a6c0SStefan Hajnoczi job->speed = value; 2385094a6c0SStefan Hajnoczi ratelimit_set_speed(&s->limit, value / BDRV_SECTOR_SIZE); 2395094a6c0SStefan Hajnoczi return 0; 2405094a6c0SStefan Hajnoczi } 2415094a6c0SStefan Hajnoczi 2424f1043b4SStefan Hajnoczi static BlockJobType stream_job_type = { 2434f1043b4SStefan Hajnoczi .instance_size = sizeof(StreamBlockJob), 2444f1043b4SStefan Hajnoczi .job_type = "stream", 2455094a6c0SStefan Hajnoczi .set_speed = stream_set_speed, 2464f1043b4SStefan Hajnoczi }; 2474f1043b4SStefan Hajnoczi 2484f1043b4SStefan Hajnoczi int stream_start(BlockDriverState *bs, BlockDriverState *base, 249*c8c3080fSMarcelo Tosatti const char *base_id, BlockDriverCompletionFunc *cb, 250*c8c3080fSMarcelo Tosatti void *opaque) 2514f1043b4SStefan Hajnoczi { 2524f1043b4SStefan Hajnoczi StreamBlockJob *s; 2534f1043b4SStefan Hajnoczi Coroutine *co; 2544f1043b4SStefan Hajnoczi 2554f1043b4SStefan Hajnoczi s = block_job_create(&stream_job_type, bs, cb, opaque); 2564f1043b4SStefan Hajnoczi if (!s) { 2574f1043b4SStefan Hajnoczi return -EBUSY; /* bs must already be in use */ 2584f1043b4SStefan Hajnoczi } 2594f1043b4SStefan Hajnoczi 2604f1043b4SStefan Hajnoczi s->base = base; 261*c8c3080fSMarcelo Tosatti if (base_id) { 262*c8c3080fSMarcelo Tosatti pstrcpy(s->backing_file_id, sizeof(s->backing_file_id), base_id); 263*c8c3080fSMarcelo Tosatti } 2644f1043b4SStefan Hajnoczi 2654f1043b4SStefan Hajnoczi co = qemu_coroutine_create(stream_run); 2664f1043b4SStefan Hajnoczi trace_stream_start(bs, base, s, co, opaque); 2674f1043b4SStefan Hajnoczi qemu_coroutine_enter(co, s); 2684f1043b4SStefan Hajnoczi return 0; 2694f1043b4SStefan Hajnoczi } 270