diff options
Diffstat (limited to 'block/vpc.c')
| -rw-r--r-- | block/vpc.c | 1255 |
1 files changed, 1255 insertions, 0 deletions
diff --git a/block/vpc.c b/block/vpc.c new file mode 100644 index 000000000..297a26262 --- /dev/null +++ b/block/vpc.c @@ -0,0 +1,1255 @@ +/* + * Block driver for Connectix / Microsoft Virtual PC images + * + * Copyright (c) 2005 Alex Beregszaszi + * Copyright (c) 2009 Kevin Wolf <kwolf@suse.de> + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +#include "qemu/osdep.h" +#include "qapi/error.h" +#include "block/block_int.h" +#include "block/qdict.h" +#include "sysemu/block-backend.h" +#include "qemu/module.h" +#include "qemu/option.h" +#include "migration/blocker.h" +#include "qemu/bswap.h" +#include "qemu/uuid.h" +#include "qapi/qmp/qdict.h" +#include "qapi/qobject-input-visitor.h" +#include "qapi/qapi-visit-block-core.h" + +/**************************************************************/ + +//#define CACHE + +enum vhd_type { + VHD_FIXED = 2, + VHD_DYNAMIC = 3, + VHD_DIFFERENCING = 4, +}; + +/* Seconds since Jan 1, 2000 0:00:00 (UTC) */ +#define VHD_TIMESTAMP_BASE 946684800 + +#define VHD_CHS_MAX_C 65535LL +#define VHD_CHS_MAX_H 16 +#define VHD_CHS_MAX_S 255 + +#define VHD_MAX_SECTORS 0xff000000 /* 2040 GiB max image size */ +#define VHD_MAX_GEOMETRY (VHD_CHS_MAX_C * VHD_CHS_MAX_H * VHD_CHS_MAX_S) + +#define VPC_OPT_FORCE_SIZE "force_size" + +/* always big-endian */ +typedef struct vhd_footer { + char creator[8]; /* "conectix" */ + uint32_t features; + uint32_t version; + + /* Offset of next header structure, 0xFFFFFFFF if none */ + uint64_t data_offset; + + /* Seconds since Jan 1, 2000 0:00:00 (UTC) */ + uint32_t timestamp; + + char creator_app[4]; /* e.g., "vpc " */ + uint16_t major; + uint16_t minor; + char creator_os[4]; /* "Wi2k" */ + + uint64_t orig_size; + uint64_t current_size; + + uint16_t cyls; + uint8_t heads; + uint8_t secs_per_cyl; + + uint32_t type; + + /* Checksum of the Hard Disk Footer ("one's complement of the sum of all + the bytes in the footer without the checksum field") */ + uint32_t checksum; + + /* UUID used to identify a parent hard disk (backing file) */ + QemuUUID uuid; + + uint8_t in_saved_state; + uint8_t reserved[427]; +} QEMU_PACKED VHDFooter; + +QEMU_BUILD_BUG_ON(sizeof(VHDFooter) != 512); + +typedef struct vhd_dyndisk_header { + char magic[8]; /* "cxsparse" */ + + /* Offset of next header structure, 0xFFFFFFFF if none */ + uint64_t data_offset; + + /* Offset of the Block Allocation Table (BAT) */ + uint64_t table_offset; + + uint32_t version; + uint32_t max_table_entries; /* 32bit/entry */ + + /* 2 MB by default, must be a power of two */ + uint32_t block_size; + + uint32_t checksum; + uint8_t parent_uuid[16]; + uint32_t parent_timestamp; + uint32_t reserved; + + /* Backing file name (in UTF-16) */ + uint8_t parent_name[512]; + + struct { + uint32_t platform; + uint32_t data_space; + uint32_t data_length; + uint32_t reserved; + uint64_t data_offset; + } parent_locator[8]; + uint8_t reserved2[256]; +} QEMU_PACKED VHDDynDiskHeader; + +QEMU_BUILD_BUG_ON(sizeof(VHDDynDiskHeader) != 1024); + +typedef struct BDRVVPCState { + CoMutex lock; + VHDFooter footer; + uint64_t free_data_block_offset; + int max_table_entries; + uint32_t *pagetable; + uint64_t bat_offset; + uint64_t last_bitmap_offset; + + uint32_t block_size; + uint32_t bitmap_size; + bool force_use_chs; + bool force_use_sz; + +#ifdef CACHE + uint8_t *pageentry_u8; + uint32_t *pageentry_u32; + uint16_t *pageentry_u16; + + uint64_t last_bitmap; +#endif + + Error *migration_blocker; +} BDRVVPCState; + +#define VPC_OPT_SIZE_CALC "force_size_calc" +static QemuOptsList vpc_runtime_opts = { + .name = "vpc-runtime-opts", + .head = QTAILQ_HEAD_INITIALIZER(vpc_runtime_opts.head), + .desc = { + { + .name = VPC_OPT_SIZE_CALC, + .type = QEMU_OPT_STRING, + .help = "Force disk size calculation to use either CHS geometry, " + "or use the disk current_size specified in the VHD footer. " + "{chs, current_size}" + }, + { /* end of list */ } + } +}; + +static QemuOptsList vpc_create_opts; + +static uint32_t vpc_checksum(void *p, size_t size) +{ + uint8_t *buf = p; + uint32_t res = 0; + int i; + + for (i = 0; i < size; i++) + res += buf[i]; + + return ~res; +} + + +static int vpc_probe(const uint8_t *buf, int buf_size, const char *filename) +{ + if (buf_size >= 8 && !strncmp((char *)buf, "conectix", 8)) + return 100; + return 0; +} + +static void vpc_parse_options(BlockDriverState *bs, QemuOpts *opts, + Error **errp) +{ + BDRVVPCState *s = bs->opaque; + const char *size_calc; + + size_calc = qemu_opt_get(opts, VPC_OPT_SIZE_CALC); + + if (!size_calc) { + /* no override, use autodetect only */ + } else if (!strcmp(size_calc, "current_size")) { + s->force_use_sz = true; + } else if (!strcmp(size_calc, "chs")) { + s->force_use_chs = true; + } else { + error_setg(errp, "Invalid size calculation mode: '%s'", size_calc); + } +} + +static int vpc_open(BlockDriverState *bs, QDict *options, int flags, + Error **errp) +{ + BDRVVPCState *s = bs->opaque; + int i; + VHDFooter *footer; + QemuOpts *opts = NULL; + Error *local_err = NULL; + bool use_chs; + VHDDynDiskHeader dyndisk_header; + uint32_t checksum; + uint64_t computed_size; + uint64_t pagetable_size; + int disk_type = VHD_DYNAMIC; + int ret; + int64_t bs_size; + + bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds, + BDRV_CHILD_IMAGE, false, errp); + if (!bs->file) { + return -EINVAL; + } + + opts = qemu_opts_create(&vpc_runtime_opts, NULL, 0, &error_abort); + if (!qemu_opts_absorb_qdict(opts, options, errp)) { + ret = -EINVAL; + goto fail; + } + + vpc_parse_options(bs, opts, &local_err); + if (local_err) { + error_propagate(errp, local_err); + ret = -EINVAL; + goto fail; + } + + ret = bdrv_pread(bs->file, 0, &s->footer, sizeof(s->footer)); + if (ret < 0) { + error_setg(errp, "Unable to read VHD header"); + goto fail; + } + + footer = &s->footer; + if (strncmp(footer->creator, "conectix", 8)) { + int64_t offset = bdrv_getlength(bs->file->bs); + if (offset < 0) { + ret = offset; + error_setg(errp, "Invalid file size"); + goto fail; + } else if (offset < sizeof(*footer)) { + ret = -EINVAL; + error_setg(errp, "File too small for a VHD header"); + goto fail; + } + + /* If a fixed disk, the footer is found only at the end of the file */ + ret = bdrv_pread(bs->file, offset - sizeof(*footer), + footer, sizeof(*footer)); + if (ret < 0) { + goto fail; + } + if (strncmp(footer->creator, "conectix", 8) || + be32_to_cpu(footer->type) != VHD_FIXED) { + error_setg(errp, "invalid VPC image"); + ret = -EINVAL; + goto fail; + } + disk_type = VHD_FIXED; + } + + checksum = be32_to_cpu(footer->checksum); + footer->checksum = 0; + if (vpc_checksum(footer, sizeof(*footer)) != checksum) { + error_setg(errp, "Incorrect header checksum"); + ret = -EINVAL; + goto fail; + } + + /* Write 'checksum' back to footer, or else will leave it with zero. */ + footer->checksum = cpu_to_be32(checksum); + + /* The visible size of a image in Virtual PC depends on the geometry + rather than on the size stored in the footer (the size in the footer + is too large usually) */ + bs->total_sectors = (int64_t) + be16_to_cpu(footer->cyls) * footer->heads * footer->secs_per_cyl; + + /* Microsoft Virtual PC and Microsoft Hyper-V produce and read + * VHD image sizes differently. VPC will rely on CHS geometry, + * while Hyper-V and disk2vhd use the size specified in the footer. + * + * We use a couple of approaches to try and determine the correct method: + * look at the Creator App field, and look for images that have CHS + * geometry that is the maximum value. + * + * If the CHS geometry is the maximum CHS geometry, then we assume that + * the size is the footer->current_size to avoid truncation. Otherwise, + * we follow the table based on footer->creator_app: + * + * Known creator apps: + * 'vpc ' : CHS Virtual PC (uses disk geometry) + * 'qemu' : CHS QEMU (uses disk geometry) + * 'qem2' : current_size QEMU (uses current_size) + * 'win ' : current_size Hyper-V + * 'd2v ' : current_size Disk2vhd + * 'tap\0' : current_size XenServer + * 'CTXS' : current_size XenConverter + * + * The user can override the table values via drive options, however + * even with an override we will still use current_size for images + * that have CHS geometry of the maximum size. + */ + use_chs = (!!strncmp(footer->creator_app, "win ", 4) && + !!strncmp(footer->creator_app, "qem2", 4) && + !!strncmp(footer->creator_app, "d2v ", 4) && + !!strncmp(footer->creator_app, "CTXS", 4) && + !!memcmp(footer->creator_app, "tap", 4)) || s->force_use_chs; + + if (!use_chs || bs->total_sectors == VHD_MAX_GEOMETRY || s->force_use_sz) { + bs->total_sectors = be64_to_cpu(footer->current_size) / + BDRV_SECTOR_SIZE; + } + + /* Allow a maximum disk size of 2040 GiB */ + if (bs->total_sectors > VHD_MAX_SECTORS) { + ret = -EFBIG; + goto fail; + } + + if (disk_type == VHD_DYNAMIC) { + ret = bdrv_pread(bs->file, be64_to_cpu(footer->data_offset), + &dyndisk_header, sizeof(dyndisk_header)); + if (ret < 0) { + error_setg(errp, "Error reading dynamic VHD header"); + goto fail; + } + + if (strncmp(dyndisk_header.magic, "cxsparse", 8)) { + error_setg(errp, "Invalid header magic"); + ret = -EINVAL; + goto fail; + } + + s->block_size = be32_to_cpu(dyndisk_header.block_size); + if (!is_power_of_2(s->block_size) || s->block_size < BDRV_SECTOR_SIZE) { + error_setg(errp, "Invalid block size %" PRIu32, s->block_size); + ret = -EINVAL; + goto fail; + } + s->bitmap_size = ((s->block_size / (8 * 512)) + 511) & ~511; + + s->max_table_entries = be32_to_cpu(dyndisk_header.max_table_entries); + + if ((bs->total_sectors * 512) / s->block_size > 0xffffffffU) { + error_setg(errp, "Too many blocks"); + ret = -EINVAL; + goto fail; + } + + computed_size = (uint64_t) s->max_table_entries * s->block_size; + if (computed_size < bs->total_sectors * 512) { + error_setg(errp, "Page table too small"); + ret = -EINVAL; + goto fail; + } + + if (s->max_table_entries > SIZE_MAX / 4 || + s->max_table_entries > (int) INT_MAX / 4) { + error_setg(errp, "Max Table Entries too large (%" PRId32 ")", + s->max_table_entries); + ret = -EINVAL; + goto fail; + } + + pagetable_size = (uint64_t) s->max_table_entries * 4; + + s->pagetable = qemu_try_blockalign(bs->file->bs, pagetable_size); + if (s->pagetable == NULL) { + error_setg(errp, "Unable to allocate memory for page table"); + ret = -ENOMEM; + goto fail; + } + + s->bat_offset = be64_to_cpu(dyndisk_header.table_offset); + + ret = bdrv_pread(bs->file, s->bat_offset, s->pagetable, + pagetable_size); + if (ret < 0) { + error_setg(errp, "Error reading pagetable"); + goto fail; + } + + s->free_data_block_offset = + ROUND_UP(s->bat_offset + pagetable_size, 512); + + for (i = 0; i < s->max_table_entries; i++) { + be32_to_cpus(&s->pagetable[i]); + if (s->pagetable[i] != 0xFFFFFFFF) { + int64_t next = (512 * (int64_t) s->pagetable[i]) + + s->bitmap_size + s->block_size; + + if (next > s->free_data_block_offset) { + s->free_data_block_offset = next; + } + } + } + + bs_size = bdrv_getlength(bs->file->bs); + if (bs_size < 0) { + error_setg_errno(errp, -bs_size, "Unable to learn image size"); + ret = bs_size; + goto fail; + } + if (s->free_data_block_offset > bs_size) { + error_setg(errp, "block-vpc: free_data_block_offset points after " + "the end of file. The image has been truncated."); + ret = -EINVAL; + goto fail; + } + + s->last_bitmap_offset = (int64_t) -1; + +#ifdef CACHE + s->pageentry_u8 = g_malloc(512); + s->pageentry_u32 = s->pageentry_u8; + s->pageentry_u16 = s->pageentry_u8; + s->last_pagetable = -1; +#endif + } + + /* Disable migration when VHD images are used */ + error_setg(&s->migration_blocker, "The vpc format used by node '%s' " + "does not support live migration", + bdrv_get_device_or_node_name(bs)); + ret = migrate_add_blocker(s->migration_blocker, errp); + if (ret < 0) { + error_free(s->migration_blocker); + goto fail; + } + + qemu_co_mutex_init(&s->lock); + qemu_opts_del(opts); + + return 0; + +fail: + qemu_opts_del(opts); + qemu_vfree(s->pagetable); +#ifdef CACHE + g_free(s->pageentry_u8); +#endif + return ret; +} + +static int vpc_reopen_prepare(BDRVReopenState *state, + BlockReopenQueue *queue, Error **errp) +{ + return 0; +} + +/* + * Returns the absolute byte offset of the given sector in the image file. + * If the sector is not allocated, -1 is returned instead. + * If an error occurred trying to write an updated block bitmap back to + * the file, -2 is returned, and the error value is written to *err. + * This can only happen for a write operation. + * + * The parameter write must be 1 if the offset will be used for a write + * operation (the block bitmaps is updated then), 0 otherwise. + * If write is true then err must not be NULL. + */ +static inline int64_t get_image_offset(BlockDriverState *bs, uint64_t offset, + bool write, int *err) +{ + BDRVVPCState *s = bs->opaque; + uint64_t bitmap_offset, block_offset; + uint32_t pagetable_index, offset_in_block; + + assert(!(write && err == NULL)); + + pagetable_index = offset / s->block_size; + offset_in_block = offset % s->block_size; + + if (pagetable_index >= s->max_table_entries || s->pagetable[pagetable_index] == 0xffffffff) + return -1; /* not allocated */ + + bitmap_offset = 512 * (uint64_t) s->pagetable[pagetable_index]; + block_offset = bitmap_offset + s->bitmap_size + offset_in_block; + + /* We must ensure that we don't write to any sectors which are marked as + unused in the bitmap. We get away with setting all bits in the block + bitmap each time we write to a new block. This might cause Virtual PC to + miss sparse read optimization, but it's not a problem in terms of + correctness. */ + if (write && (s->last_bitmap_offset != bitmap_offset)) { + uint8_t bitmap[s->bitmap_size]; + int r; + + s->last_bitmap_offset = bitmap_offset; + memset(bitmap, 0xff, s->bitmap_size); + r = bdrv_pwrite_sync(bs->file, bitmap_offset, bitmap, s->bitmap_size); + if (r < 0) { + *err = r; + return -2; + } + } + + return block_offset; +} + +/* + * Writes the footer to the end of the image file. This is needed when the + * file grows as it overwrites the old footer + * + * Returns 0 on success and < 0 on error + */ +static int rewrite_footer(BlockDriverState *bs) +{ + int ret; + BDRVVPCState *s = bs->opaque; + int64_t offset = s->free_data_block_offset; + + ret = bdrv_pwrite_sync(bs->file, offset, &s->footer, sizeof(s->footer)); + if (ret < 0) + return ret; + + return 0; +} + +/* + * Allocates a new block. This involves writing a new footer and updating + * the Block Allocation Table to use the space at the old end of the image + * file (overwriting the old footer) + * + * Returns the sectors' offset in the image file on success and < 0 on error + */ +static int64_t alloc_block(BlockDriverState *bs, int64_t offset) +{ + BDRVVPCState *s = bs->opaque; + int64_t bat_offset; + uint32_t index, bat_value; + int ret; + uint8_t bitmap[s->bitmap_size]; + + /* Check if sector_num is valid */ + if ((offset < 0) || (offset > bs->total_sectors * BDRV_SECTOR_SIZE)) { + return -EINVAL; + } + + /* Write entry into in-memory BAT */ + index = offset / s->block_size; + assert(s->pagetable[index] == 0xFFFFFFFF); + s->pagetable[index] = s->free_data_block_offset / 512; + + /* Initialize the block's bitmap */ + memset(bitmap, 0xff, s->bitmap_size); + ret = bdrv_pwrite_sync(bs->file, s->free_data_block_offset, bitmap, + s->bitmap_size); + if (ret < 0) { + return ret; + } + + /* Write new footer (the old one will be overwritten) */ + s->free_data_block_offset += s->block_size + s->bitmap_size; + ret = rewrite_footer(bs); + if (ret < 0) + goto fail; + + /* Write BAT entry to disk */ + bat_offset = s->bat_offset + (4 * index); + bat_value = cpu_to_be32(s->pagetable[index]); + ret = bdrv_pwrite_sync(bs->file, bat_offset, &bat_value, 4); + if (ret < 0) + goto fail; + + return get_image_offset(bs, offset, false, NULL); + +fail: + s->free_data_block_offset -= (s->block_size + s->bitmap_size); + return ret; +} + +static int vpc_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) +{ + BDRVVPCState *s = (BDRVVPCState *)bs->opaque; + + if (be32_to_cpu(s->footer.type) != VHD_FIXED) { + bdi->cluster_size = s->block_size; + } + + return 0; +} + +static int coroutine_fn +vpc_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes, + QEMUIOVector *qiov, BdrvRequestFlags flags) +{ + BDRVVPCState *s = bs->opaque; + int ret; + int64_t image_offset; + int64_t n_bytes; + int64_t bytes_done = 0; + QEMUIOVector local_qiov; + + if (be32_to_cpu(s->footer.type) == VHD_FIXED) { + return bdrv_co_preadv(bs->file, offset, bytes, qiov, 0); + } + + qemu_co_mutex_lock(&s->lock); + qemu_iovec_init(&local_qiov, qiov->niov); + + while (bytes > 0) { + image_offset = get_image_offset(bs, offset, false, NULL); + n_bytes = MIN(bytes, s->block_size - (offset % s->block_size)); + + if (image_offset == -1) { + qemu_iovec_memset(qiov, bytes_done, 0, n_bytes); + } else { + qemu_iovec_reset(&local_qiov); + qemu_iovec_concat(&local_qiov, qiov, bytes_done, n_bytes); + + qemu_co_mutex_unlock(&s->lock); + ret = bdrv_co_preadv(bs->file, image_offset, n_bytes, + &local_qiov, 0); + qemu_co_mutex_lock(&s->lock); + if (ret < 0) { + goto fail; + } + } + + bytes -= n_bytes; + offset += n_bytes; + bytes_done += n_bytes; + } + + ret = 0; +fail: + qemu_iovec_destroy(&local_qiov); + qemu_co_mutex_unlock(&s->lock); + + return ret; +} + +static int coroutine_fn +vpc_co_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes, + QEMUIOVector *qiov, BdrvRequestFlags flags) +{ + BDRVVPCState *s = bs->opaque; + int64_t image_offset; + int64_t n_bytes; + int64_t bytes_done = 0; + int ret = 0; + QEMUIOVector local_qiov; + + if (be32_to_cpu(s->footer.type) == VHD_FIXED) { + return bdrv_co_pwritev(bs->file, offset, bytes, qiov, 0); + } + + qemu_co_mutex_lock(&s->lock); + qemu_iovec_init(&local_qiov, qiov->niov); + + while (bytes > 0) { + image_offset = get_image_offset(bs, offset, true, &ret); + if (image_offset == -2) { + /* Failed to write block bitmap: can't proceed with write */ + goto fail; + } + n_bytes = MIN(bytes, s->block_size - (offset % s->block_size)); + + if (image_offset == -1) { + image_offset = alloc_block(bs, offset); + if (image_offset < 0) { + ret = image_offset; + goto fail; + } + } + + qemu_iovec_reset(&local_qiov); + qemu_iovec_concat(&local_qiov, qiov, bytes_done, n_bytes); + + qemu_co_mutex_unlock(&s->lock); + ret = bdrv_co_pwritev(bs->file, image_offset, n_bytes, + &local_qiov, 0); + qemu_co_mutex_lock(&s->lock); + if (ret < 0) { + goto fail; + } + + bytes -= n_bytes; + offset += n_bytes; + bytes_done += n_bytes; + } + + ret = 0; +fail: + qemu_iovec_destroy(&local_qiov); + qemu_co_mutex_unlock(&s->lock); + + return ret; +} + +static int coroutine_fn vpc_co_block_status(BlockDriverState *bs, + bool want_zero, + int64_t offset, int64_t bytes, + int64_t *pnum, int64_t *map, + BlockDriverState **file) +{ + BDRVVPCState *s = bs->opaque; + int64_t image_offset; + bool allocated; + int ret; + int64_t n; + + if (be32_to_cpu(s->footer.type) == VHD_FIXED) { + *pnum = bytes; + *map = offset; + *file = bs->file->bs; + return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | BDRV_BLOCK_RECURSE; + } + + qemu_co_mutex_lock(&s->lock); + + image_offset = get_image_offset(bs, offset, false, NULL); + allocated = (image_offset != -1); + *pnum = 0; + ret = BDRV_BLOCK_ZERO; + + do { + /* All sectors in a block are contiguous (without using the bitmap) */ + n = ROUND_UP(offset + 1, s->block_size) - offset; + n = MIN(n, bytes); + + *pnum += n; + offset += n; + bytes -= n; + /* *pnum can't be greater than one block for allocated + * sectors since there is always a bitmap in between. */ + if (allocated) { + *file = bs->file->bs; + *map = image_offset; + ret = BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID; + break; + } + if (bytes == 0) { + break; + } + image_offset = get_image_offset(bs, offset, false, NULL); + } while (image_offset == -1); + + qemu_co_mutex_unlock(&s->lock); + return ret; +} + +/* + * Calculates the number of cylinders, heads and sectors per cylinder + * based on a given number of sectors. This is the algorithm described + * in the VHD specification. + * + * Note that the geometry doesn't always exactly match total_sectors but + * may round it down. + * + * Returns 0 on success, -EFBIG if the size is larger than 2040 GiB. Override + * the hardware EIDE and ATA-2 limit of 16 heads (max disk size of 127 GB) + * and instead allow up to 255 heads. + */ +static int calculate_geometry(int64_t total_sectors, uint16_t *cyls, + uint8_t *heads, uint8_t *secs_per_cyl) +{ + uint32_t cyls_times_heads; + + total_sectors = MIN(total_sectors, VHD_MAX_GEOMETRY); + + if (total_sectors >= 65535LL * 16 * 63) { + *secs_per_cyl = 255; + *heads = 16; + cyls_times_heads = total_sectors / *secs_per_cyl; + } else { + *secs_per_cyl = 17; + cyls_times_heads = total_sectors / *secs_per_cyl; + *heads = DIV_ROUND_UP(cyls_times_heads, 1024); + + if (*heads < 4) { + *heads = 4; + } + + if (cyls_times_heads >= (*heads * 1024) || *heads > 16) { + *secs_per_cyl = 31; + *heads = 16; + cyls_times_heads = total_sectors / *secs_per_cyl; + } + + if (cyls_times_heads >= (*heads * 1024)) { + *secs_per_cyl = 63; + *heads = 16; + cyls_times_heads = total_sectors / *secs_per_cyl; + } + } + + *cyls = cyls_times_heads / *heads; + + return 0; +} + +static int create_dynamic_disk(BlockBackend *blk, VHDFooter *footer, + int64_t total_sectors) +{ + VHDDynDiskHeader dyndisk_header; + uint8_t bat_sector[512]; + size_t block_size, num_bat_entries; + int i; + int ret; + int64_t offset = 0; + + /* Write the footer (twice: at the beginning and at the end) */ + block_size = 0x200000; + num_bat_entries = DIV_ROUND_UP(total_sectors, block_size / 512); + + ret = blk_pwrite(blk, offset, footer, sizeof(*footer), 0); + if (ret < 0) { + goto fail; + } + + offset = 1536 + ((num_bat_entries * 4 + 511) & ~511); + ret = blk_pwrite(blk, offset, footer, sizeof(*footer), 0); + if (ret < 0) { + goto fail; + } + + /* Write the initial BAT */ + offset = 3 * 512; + + memset(bat_sector, 0xFF, 512); + for (i = 0; i < DIV_ROUND_UP(num_bat_entries * 4, 512); i++) { + ret = blk_pwrite(blk, offset, bat_sector, 512, 0); + if (ret < 0) { + goto fail; + } + offset += 512; + } + + /* Prepare the Dynamic Disk Header */ + memset(&dyndisk_header, 0, sizeof(dyndisk_header)); + + memcpy(dyndisk_header.magic, "cxsparse", 8); + + /* + * Note: The spec is actually wrong here for data_offset, it says + * 0xFFFFFFFF, but MS tools expect all 64 bits to be set. + */ + dyndisk_header.data_offset = cpu_to_be64(0xFFFFFFFFFFFFFFFFULL); + dyndisk_header.table_offset = cpu_to_be64(3 * 512); + dyndisk_header.version = cpu_to_be32(0x00010000); + dyndisk_header.block_size = cpu_to_be32(block_size); + dyndisk_header.max_table_entries = cpu_to_be32(num_bat_entries); + + dyndisk_header.checksum = cpu_to_be32( + vpc_checksum(&dyndisk_header, sizeof(dyndisk_header))); + + /* Write the header */ + offset = 512; + + ret = blk_pwrite(blk, offset, &dyndisk_header, sizeof(dyndisk_header), 0); + if (ret < 0) { + goto fail; + } + + ret = 0; + fail: + return ret; +} + +static int create_fixed_disk(BlockBackend *blk, VHDFooter *footer, + int64_t total_size, Error **errp) +{ + int ret; + + /* Add footer to total size */ + total_size += sizeof(*footer); + + ret = blk_truncate(blk, total_size, false, PREALLOC_MODE_OFF, 0, errp); + if (ret < 0) { + return ret; + } + + ret = blk_pwrite(blk, total_size - sizeof(*footer), + footer, sizeof(*footer), 0); + if (ret < 0) { + error_setg_errno(errp, -ret, "Unable to write VHD header"); + return ret; + } + + return 0; +} + +static int calculate_rounded_image_size(BlockdevCreateOptionsVpc *vpc_opts, + uint16_t *out_cyls, + uint8_t *out_heads, + uint8_t *out_secs_per_cyl, + int64_t *out_total_sectors, + Error **errp) +{ + int64_t total_size = vpc_opts->size; + uint16_t cyls = 0; + uint8_t heads = 0; + uint8_t secs_per_cyl = 0; + int64_t total_sectors; + int i; + + /* + * Calculate matching total_size and geometry. Increase the number of + * sectors requested until we get enough (or fail). This ensures that + * qemu-img convert doesn't truncate images, but rather rounds up. + * + * If the image size can't be represented by a spec conformant CHS geometry, + * we set the geometry to 65535 x 16 x 255 (CxHxS) sectors and use + * the image size from the VHD footer to calculate total_sectors. + */ + if (vpc_opts->force_size) { + /* This will force the use of total_size for sector count, below */ + cyls = VHD_CHS_MAX_C; + heads = VHD_CHS_MAX_H; + secs_per_cyl = VHD_CHS_MAX_S; + } else { + total_sectors = MIN(VHD_MAX_GEOMETRY, total_size / BDRV_SECTOR_SIZE); + for (i = 0; total_sectors > (int64_t)cyls * heads * secs_per_cyl; i++) { + calculate_geometry(total_sectors + i, &cyls, &heads, &secs_per_cyl); + } + } + + if ((int64_t)cyls * heads * secs_per_cyl == VHD_MAX_GEOMETRY) { + total_sectors = total_size / BDRV_SECTOR_SIZE; + /* Allow a maximum disk size of 2040 GiB */ + if (total_sectors > VHD_MAX_SECTORS) { + error_setg(errp, "Disk size is too large, max size is 2040 GiB"); + return -EFBIG; + } + } else { + total_sectors = (int64_t) cyls * heads * secs_per_cyl; + } + + *out_total_sectors = total_sectors; + if (out_cyls) { + *out_cyls = cyls; + *out_heads = heads; + *out_secs_per_cyl = secs_per_cyl; + } + + return 0; +} + +static int coroutine_fn vpc_co_create(BlockdevCreateOptions *opts, + Error **errp) +{ + BlockdevCreateOptionsVpc *vpc_opts; + BlockBackend *blk = NULL; + BlockDriverState *bs = NULL; + + VHDFooter footer; + uint16_t cyls = 0; + uint8_t heads = 0; + uint8_t secs_per_cyl = 0; + int64_t total_sectors; + int64_t total_size; + int disk_type; + int ret = -EIO; + QemuUUID uuid; + + assert(opts->driver == BLOCKDEV_DRIVER_VPC); + vpc_opts = &opts->u.vpc; + + /* Validate options and set default values */ + total_size = vpc_opts->size; + + if (!vpc_opts->has_subformat) { + vpc_opts->subformat = BLOCKDEV_VPC_SUBFORMAT_DYNAMIC; + } + switch (vpc_opts->subformat) { + case BLOCKDEV_VPC_SUBFORMAT_DYNAMIC: + disk_type = VHD_DYNAMIC; + break; + case BLOCKDEV_VPC_SUBFORMAT_FIXED: + disk_type = VHD_FIXED; + break; + default: + g_assert_not_reached(); + } + + /* Create BlockBackend to write to the image */ + bs = bdrv_open_blockdev_ref(vpc_opts->file, errp); + if (bs == NULL) { + return -EIO; + } + + blk = blk_new_with_bs(bs, BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL, + errp); + if (!blk) { + ret = -EPERM; + goto out; + } + blk_set_allow_write_beyond_eof(blk, true); + + /* Get geometry and check that it matches the image size*/ + ret = calculate_rounded_image_size(vpc_opts, &cyls, &heads, &secs_per_cyl, + &total_sectors, errp); + if (ret < 0) { + goto out; + } + + if (total_size != total_sectors * BDRV_SECTOR_SIZE) { + error_setg(errp, "The requested image size cannot be represented in " + "CHS geometry"); + error_append_hint(errp, "Try size=%llu or force-size=on (the " + "latter makes the image incompatible with " + "Virtual PC)", + total_sectors * BDRV_SECTOR_SIZE); + ret = -EINVAL; + goto out; + } + + /* Prepare the Hard Disk Footer */ + memset(&footer, 0, sizeof(footer)); + + memcpy(footer.creator, "conectix", 8); + if (vpc_opts->force_size) { + memcpy(footer.creator_app, "qem2", 4); + } else { + memcpy(footer.creator_app, "qemu", 4); + } + memcpy(footer.creator_os, "Wi2k", 4); + + footer.features = cpu_to_be32(0x02); + footer.version = cpu_to_be32(0x00010000); + if (disk_type == VHD_DYNAMIC) { + footer.data_offset = cpu_to_be64(sizeof(footer)); + } else { + footer.data_offset = cpu_to_be64(0xFFFFFFFFFFFFFFFFULL); + } + footer.timestamp = cpu_to_be32(time(NULL) - VHD_TIMESTAMP_BASE); + + /* Version of Virtual PC 2007 */ + footer.major = cpu_to_be16(0x0005); + footer.minor = cpu_to_be16(0x0003); + footer.orig_size = cpu_to_be64(total_size); + footer.current_size = cpu_to_be64(total_size); + footer.cyls = cpu_to_be16(cyls); + footer.heads = heads; + footer.secs_per_cyl = secs_per_cyl; + + footer.type = cpu_to_be32(disk_type); + + qemu_uuid_generate(&uuid); + footer.uuid = uuid; + + footer.checksum = cpu_to_be32(vpc_checksum(&footer, sizeof(footer))); + + if (disk_type == VHD_DYNAMIC) { + ret = create_dynamic_disk(blk, &footer, total_sectors); + if (ret < 0) { + error_setg(errp, "Unable to create or write VHD header"); + } + } else { + ret = create_fixed_disk(blk, &footer, total_size, errp); + } + +out: + blk_unref(blk); + bdrv_unref(bs); + return ret; +} + +static int coroutine_fn vpc_co_create_opts(BlockDriver *drv, + const char *filename, + QemuOpts *opts, + Error **errp) +{ + BlockdevCreateOptions *create_options = NULL; + QDict *qdict; + Visitor *v; + BlockDriverState *bs = NULL; + int ret; + + static const QDictRenames opt_renames[] = { + { VPC_OPT_FORCE_SIZE, "force-size" }, + { NULL, NULL }, + }; + + /* Parse options and convert legacy syntax */ + qdict = qemu_opts_to_qdict_filtered(opts, NULL, &vpc_create_opts, true); + + if (!qdict_rename_keys(qdict, opt_renames, errp)) { + ret = -EINVAL; + goto fail; + } + + /* Create and open the file (protocol layer) */ + ret = bdrv_create_file(filename, opts, errp); + if (ret < 0) { + goto fail; + } + + bs = bdrv_open(filename, NULL, NULL, + BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp); + if (bs == NULL) { + ret = -EIO; + goto fail; + } + + /* Now get the QAPI type BlockdevCreateOptions */ + qdict_put_str(qdict, "driver", "vpc"); + qdict_put_str(qdict, "file", bs->node_name); + + v = qobject_input_visitor_new_flat_confused(qdict, errp); + if (!v) { + ret = -EINVAL; + goto fail; + } + + visit_type_BlockdevCreateOptions(v, NULL, &create_options, errp); + visit_free(v); + if (!create_options) { + ret = -EINVAL; + goto fail; + } + + /* Silently round up size */ + assert(create_options->driver == BLOCKDEV_DRIVER_VPC); + create_options->u.vpc.size = + ROUND_UP(create_options->u.vpc.size, BDRV_SECTOR_SIZE); + + if (!create_options->u.vpc.force_size) { + int64_t total_sectors; + ret = calculate_rounded_image_size(&create_options->u.vpc, NULL, NULL, + NULL, &total_sectors, errp); + if (ret < 0) { + goto fail; + } + + create_options->u.vpc.size = total_sectors * BDRV_SECTOR_SIZE; + } + + + /* Create the vpc image (format layer) */ + ret = vpc_co_create(create_options, errp); + +fail: + qobject_unref(qdict); + bdrv_unref(bs); + qapi_free_BlockdevCreateOptions(create_options); + return ret; +} + + +static int vpc_has_zero_init(BlockDriverState *bs) +{ + BDRVVPCState *s = bs->opaque; + + if (be32_to_cpu(s->footer.type) == VHD_FIXED) { + return bdrv_has_zero_init(bs->file->bs); + } else { + return 1; + } +} + +static void vpc_close(BlockDriverState *bs) +{ + BDRVVPCState *s = bs->opaque; + qemu_vfree(s->pagetable); +#ifdef CACHE + g_free(s->pageentry_u8); +#endif + + migrate_del_blocker(s->migration_blocker); + error_free(s->migration_blocker); +} + +static QemuOptsList vpc_create_opts = { + .name = "vpc-create-opts", + .head = QTAILQ_HEAD_INITIALIZER(vpc_create_opts.head), + .desc = { + { + .name = BLOCK_OPT_SIZE, + .type = QEMU_OPT_SIZE, + .help = "Virtual disk size" + }, + { + .name = BLOCK_OPT_SUBFMT, + .type = QEMU_OPT_STRING, + .help = + "Type of virtual hard disk format. Supported formats are " + "{dynamic (default) | fixed} " + }, + { + .name = VPC_OPT_FORCE_SIZE, + .type = QEMU_OPT_BOOL, + .help = "Force disk size calculation to use the actual size " + "specified, rather than using the nearest CHS-based " + "calculation" + }, + { /* end of list */ } + } +}; + +static const char *const vpc_strong_runtime_opts[] = { + VPC_OPT_SIZE_CALC, + + NULL +}; + +static BlockDriver bdrv_vpc = { + .format_name = "vpc", + .instance_size = sizeof(BDRVVPCState), + + .bdrv_probe = vpc_probe, + .bdrv_open = vpc_open, + .bdrv_close = vpc_close, + .bdrv_reopen_prepare = vpc_reopen_prepare, + .bdrv_child_perm = bdrv_default_perms, + .bdrv_co_create = vpc_co_create, + .bdrv_co_create_opts = vpc_co_create_opts, + + .bdrv_co_preadv = vpc_co_preadv, + .bdrv_co_pwritev = vpc_co_pwritev, + .bdrv_co_block_status = vpc_co_block_status, + + .bdrv_get_info = vpc_get_info, + + .is_format = true, + .create_opts = &vpc_create_opts, + .bdrv_has_zero_init = vpc_has_zero_init, + .strong_runtime_opts = vpc_strong_runtime_opts, +}; + +static void bdrv_vpc_init(void) +{ + bdrv_register(&bdrv_vpc); +} + +block_init(bdrv_vpc_init); |