diff options
Diffstat (limited to 'block/vhdx.c')
| -rw-r--r-- | block/vhdx.c | 972 |
1 files changed, 972 insertions, 0 deletions
diff --git a/block/vhdx.c b/block/vhdx.c new file mode 100644 index 000000000..e9704b1fd --- /dev/null +++ b/block/vhdx.c @@ -0,0 +1,972 @@ +/* + * Block driver for Hyper-V VHDX Images + * + * Copyright (c) 2013 Red Hat, Inc., + * + * Authors: + * Jeff Cody <jcody@redhat.com> + * + * This is based on the "VHDX Format Specification v0.95", published 4/12/2012 + * by Microsoft: + * https://www.microsoft.com/en-us/download/details.aspx?id=29681 + * + * This work is licensed under the terms of the GNU LGPL, version 2 or later. + * See the COPYING.LIB file in the top-level directory. + * + */ + +#include "qemu-common.h" +#include "block/block_int.h" +#include "qemu/module.h" +#include "qemu/crc32c.h" +#include "block/vhdx.h" + + +/* Several metadata and region table data entries are identified by + * guids in a MS-specific GUID format. */ + + +/* ------- Known Region Table GUIDs ---------------------- */ +static const MSGUID bat_guid = { .data1 = 0x2dc27766, + .data2 = 0xf623, + .data3 = 0x4200, + .data4 = { 0x9d, 0x64, 0x11, 0x5e, + 0x9b, 0xfd, 0x4a, 0x08} }; + +static const MSGUID metadata_guid = { .data1 = 0x8b7ca206, + .data2 = 0x4790, + .data3 = 0x4b9a, + .data4 = { 0xb8, 0xfe, 0x57, 0x5f, + 0x05, 0x0f, 0x88, 0x6e} }; + + + +/* ------- Known Metadata Entry GUIDs ---------------------- */ +static const MSGUID file_param_guid = { .data1 = 0xcaa16737, + .data2 = 0xfa36, + .data3 = 0x4d43, + .data4 = { 0xb3, 0xb6, 0x33, 0xf0, + 0xaa, 0x44, 0xe7, 0x6b} }; + +static const MSGUID virtual_size_guid = { .data1 = 0x2FA54224, + .data2 = 0xcd1b, + .data3 = 0x4876, + .data4 = { 0xb2, 0x11, 0x5d, 0xbe, + 0xd8, 0x3b, 0xf4, 0xb8} }; + +static const MSGUID page83_guid = { .data1 = 0xbeca12ab, + .data2 = 0xb2e6, + .data3 = 0x4523, + .data4 = { 0x93, 0xef, 0xc3, 0x09, + 0xe0, 0x00, 0xc7, 0x46} }; + + +static const MSGUID phys_sector_guid = { .data1 = 0xcda348c7, + .data2 = 0x445d, + .data3 = 0x4471, + .data4 = { 0x9c, 0xc9, 0xe9, 0x88, + 0x52, 0x51, 0xc5, 0x56} }; + +static const MSGUID parent_locator_guid = { .data1 = 0xa8d35f2d, + .data2 = 0xb30b, + .data3 = 0x454d, + .data4 = { 0xab, 0xf7, 0xd3, + 0xd8, 0x48, 0x34, + 0xab, 0x0c} }; + +static const MSGUID logical_sector_guid = { .data1 = 0x8141bf1d, + .data2 = 0xa96f, + .data3 = 0x4709, + .data4 = { 0xba, 0x47, 0xf2, + 0x33, 0xa8, 0xfa, + 0xab, 0x5f} }; + +/* Each parent type must have a valid GUID; this is for parent images + * of type 'VHDX'. If we were to allow e.g. a QCOW2 parent, we would + * need to make up our own QCOW2 GUID type */ +static const MSGUID parent_vhdx_guid = { .data1 = 0xb04aefb7, + .data2 = 0xd19e, + .data3 = 0x4a81, + .data4 = { 0xb7, 0x89, 0x25, 0xb8, + 0xe9, 0x44, 0x59, 0x13} }; + + +#define META_FILE_PARAMETER_PRESENT 0x01 +#define META_VIRTUAL_DISK_SIZE_PRESENT 0x02 +#define META_PAGE_83_PRESENT 0x04 +#define META_LOGICAL_SECTOR_SIZE_PRESENT 0x08 +#define META_PHYS_SECTOR_SIZE_PRESENT 0x10 +#define META_PARENT_LOCATOR_PRESENT 0x20 + +#define META_ALL_PRESENT \ + (META_FILE_PARAMETER_PRESENT | META_VIRTUAL_DISK_SIZE_PRESENT | \ + META_PAGE_83_PRESENT | META_LOGICAL_SECTOR_SIZE_PRESENT | \ + META_PHYS_SECTOR_SIZE_PRESENT) + +typedef struct VHDXMetadataEntries { + VHDXMetadataTableEntry file_parameters_entry; + VHDXMetadataTableEntry virtual_disk_size_entry; + VHDXMetadataTableEntry page83_data_entry; + VHDXMetadataTableEntry logical_sector_size_entry; + VHDXMetadataTableEntry phys_sector_size_entry; + VHDXMetadataTableEntry parent_locator_entry; + uint16_t present; +} VHDXMetadataEntries; + + +typedef struct VHDXSectorInfo { + uint32_t bat_idx; /* BAT entry index */ + uint32_t sectors_avail; /* sectors available in payload block */ + uint32_t bytes_left; /* bytes left in the block after data to r/w */ + uint32_t bytes_avail; /* bytes available in payload block */ + uint64_t file_offset; /* absolute offset in bytes, in file */ + uint64_t block_offset; /* block offset, in bytes */ +} VHDXSectorInfo; + + + +typedef struct BDRVVHDXState { + CoMutex lock; + + int curr_header; + VHDXHeader *headers[2]; + + VHDXRegionTableHeader rt; + VHDXRegionTableEntry bat_rt; /* region table for the BAT */ + VHDXRegionTableEntry metadata_rt; /* region table for the metadata */ + + VHDXMetadataTableHeader metadata_hdr; + VHDXMetadataEntries metadata_entries; + + VHDXFileParameters params; + uint32_t block_size; + uint32_t block_size_bits; + uint32_t sectors_per_block; + uint32_t sectors_per_block_bits; + + uint64_t virtual_disk_size; + uint32_t logical_sector_size; + uint32_t physical_sector_size; + + uint64_t chunk_ratio; + uint32_t chunk_ratio_bits; + uint32_t logical_sector_size_bits; + + uint32_t bat_entries; + VHDXBatEntry *bat; + uint64_t bat_offset; + + VHDXParentLocatorHeader parent_header; + VHDXParentLocatorEntry *parent_entries; + +} BDRVVHDXState; + +uint32_t vhdx_checksum_calc(uint32_t crc, uint8_t *buf, size_t size, + int crc_offset) +{ + uint32_t crc_new; + uint32_t crc_orig; + assert(buf != NULL); + + if (crc_offset > 0) { + memcpy(&crc_orig, buf + crc_offset, sizeof(crc_orig)); + memset(buf + crc_offset, 0, sizeof(crc_orig)); + } + + crc_new = crc32c(crc, buf, size); + if (crc_offset > 0) { + memcpy(buf + crc_offset, &crc_orig, sizeof(crc_orig)); + } + + return crc_new; +} + +/* Validates the checksum of the buffer, with an in-place CRC. + * + * Zero is substituted during crc calculation for the original crc field, + * and the crc field is restored afterwards. But the buffer will be modifed + * during the calculation, so this may not be not suitable for multi-threaded + * use. + * + * crc_offset: byte offset in buf of the buffer crc + * buf: buffer pointer + * size: size of buffer (must be > crc_offset+4) + * + * returns true if checksum is valid, false otherwise + */ +bool vhdx_checksum_is_valid(uint8_t *buf, size_t size, int crc_offset) +{ + uint32_t crc_orig; + uint32_t crc; + + assert(buf != NULL); + assert(size > (crc_offset + 4)); + + memcpy(&crc_orig, buf + crc_offset, sizeof(crc_orig)); + crc_orig = le32_to_cpu(crc_orig); + + crc = vhdx_checksum_calc(0xffffffff, buf, size, crc_offset); + + return crc == crc_orig; +} + + +/* + * Per the MS VHDX Specification, for every VHDX file: + * - The header section is fixed size - 1 MB + * - The header section is always the first "object" + * - The first 64KB of the header is the File Identifier + * - The first uint64 (8 bytes) is the VHDX Signature ("vhdxfile") + * - The following 512 bytes constitute a UTF-16 string identifiying the + * software that created the file, and is optional and diagnostic only. + * + * Therefore, we probe by looking for the vhdxfile signature "vhdxfile" + */ +static int vhdx_probe(const uint8_t *buf, int buf_size, const char *filename) +{ + if (buf_size >= 8 && !memcmp(buf, "vhdxfile", 8)) { + return 100; + } + return 0; +} + +/* All VHDX structures on disk are little endian */ +static void vhdx_header_le_import(VHDXHeader *h) +{ + assert(h != NULL); + + le32_to_cpus(&h->signature); + le32_to_cpus(&h->checksum); + le64_to_cpus(&h->sequence_number); + + leguid_to_cpus(&h->file_write_guid); + leguid_to_cpus(&h->data_write_guid); + leguid_to_cpus(&h->log_guid); + + le16_to_cpus(&h->log_version); + le16_to_cpus(&h->version); + le32_to_cpus(&h->log_length); + le64_to_cpus(&h->log_offset); +} + + +/* opens the specified header block from the VHDX file header section */ +static int vhdx_parse_header(BlockDriverState *bs, BDRVVHDXState *s) +{ + int ret = 0; + VHDXHeader *header1; + VHDXHeader *header2; + bool h1_valid = false; + bool h2_valid = false; + uint64_t h1_seq = 0; + uint64_t h2_seq = 0; + uint8_t *buffer; + + header1 = qemu_blockalign(bs, sizeof(VHDXHeader)); + header2 = qemu_blockalign(bs, sizeof(VHDXHeader)); + + buffer = qemu_blockalign(bs, VHDX_HEADER_SIZE); + + s->headers[0] = header1; + s->headers[1] = header2; + + /* We have to read the whole VHDX_HEADER_SIZE instead of + * sizeof(VHDXHeader), because the checksum is over the whole + * region */ + ret = bdrv_pread(bs->file, VHDX_HEADER1_OFFSET, buffer, VHDX_HEADER_SIZE); + if (ret < 0) { + goto fail; + } + /* copy over just the relevant portion that we need */ + memcpy(header1, buffer, sizeof(VHDXHeader)); + vhdx_header_le_import(header1); + + if (vhdx_checksum_is_valid(buffer, VHDX_HEADER_SIZE, 4) && + !memcmp(&header1->signature, "head", 4) && + header1->version == 1) { + h1_seq = header1->sequence_number; + h1_valid = true; + } + + ret = bdrv_pread(bs->file, VHDX_HEADER2_OFFSET, buffer, VHDX_HEADER_SIZE); + if (ret < 0) { + goto fail; + } + /* copy over just the relevant portion that we need */ + memcpy(header2, buffer, sizeof(VHDXHeader)); + vhdx_header_le_import(header2); + + if (vhdx_checksum_is_valid(buffer, VHDX_HEADER_SIZE, 4) && + !memcmp(&header2->signature, "head", 4) && + header2->version == 1) { + h2_seq = header2->sequence_number; + h2_valid = true; + } + + /* If there is only 1 valid header (or no valid headers), we + * don't care what the sequence numbers are */ + if (h1_valid && !h2_valid) { + s->curr_header = 0; + } else if (!h1_valid && h2_valid) { + s->curr_header = 1; + } else if (!h1_valid && !h2_valid) { + ret = -EINVAL; + goto fail; + } else { + /* If both headers are valid, then we choose the active one by the + * highest sequence number. If the sequence numbers are equal, that is + * invalid */ + if (h1_seq > h2_seq) { + s->curr_header = 0; + } else if (h2_seq > h1_seq) { + s->curr_header = 1; + } else { + ret = -EINVAL; + goto fail; + } + } + + ret = 0; + + goto exit; + +fail: + qerror_report(ERROR_CLASS_GENERIC_ERROR, "No valid VHDX header found"); + qemu_vfree(header1); + qemu_vfree(header2); + s->headers[0] = NULL; + s->headers[1] = NULL; +exit: + qemu_vfree(buffer); + return ret; +} + + +static int vhdx_open_region_tables(BlockDriverState *bs, BDRVVHDXState *s) +{ + int ret = 0; + uint8_t *buffer; + int offset = 0; + VHDXRegionTableEntry rt_entry; + uint32_t i; + bool bat_rt_found = false; + bool metadata_rt_found = false; + + /* We have to read the whole 64KB block, because the crc32 is over the + * whole block */ + buffer = qemu_blockalign(bs, VHDX_HEADER_BLOCK_SIZE); + + ret = bdrv_pread(bs->file, VHDX_REGION_TABLE_OFFSET, buffer, + VHDX_HEADER_BLOCK_SIZE); + if (ret < 0) { + goto fail; + } + memcpy(&s->rt, buffer, sizeof(s->rt)); + le32_to_cpus(&s->rt.signature); + le32_to_cpus(&s->rt.checksum); + le32_to_cpus(&s->rt.entry_count); + le32_to_cpus(&s->rt.reserved); + offset += sizeof(s->rt); + + if (!vhdx_checksum_is_valid(buffer, VHDX_HEADER_BLOCK_SIZE, 4) || + memcmp(&s->rt.signature, "regi", 4)) { + ret = -EINVAL; + goto fail; + } + + /* Per spec, maximum region table entry count is 2047 */ + if (s->rt.entry_count > 2047) { + ret = -EINVAL; + goto fail; + } + + for (i = 0; i < s->rt.entry_count; i++) { + memcpy(&rt_entry, buffer + offset, sizeof(rt_entry)); + offset += sizeof(rt_entry); + + leguid_to_cpus(&rt_entry.guid); + le64_to_cpus(&rt_entry.file_offset); + le32_to_cpus(&rt_entry.length); + le32_to_cpus(&rt_entry.data_bits); + + /* see if we recognize the entry */ + if (guid_eq(rt_entry.guid, bat_guid)) { + /* must be unique; if we have already found it this is invalid */ + if (bat_rt_found) { + ret = -EINVAL; + goto fail; + } + bat_rt_found = true; + s->bat_rt = rt_entry; + continue; + } + + if (guid_eq(rt_entry.guid, metadata_guid)) { + /* must be unique; if we have already found it this is invalid */ + if (metadata_rt_found) { + ret = -EINVAL; + goto fail; + } + metadata_rt_found = true; + s->metadata_rt = rt_entry; + continue; + } + + if (rt_entry.data_bits & VHDX_REGION_ENTRY_REQUIRED) { + /* cannot read vhdx file - required region table entry that + * we do not understand. per spec, we must fail to open */ + ret = -ENOTSUP; + goto fail; + } + } + ret = 0; + +fail: + qemu_vfree(buffer); + return ret; +} + + + +/* Metadata initial parser + * + * This loads all the metadata entry fields. This may cause additional + * fields to be processed (e.g. parent locator, etc..). + * + * There are 5 Metadata items that are always required: + * - File Parameters (block size, has a parent) + * - Virtual Disk Size (size, in bytes, of the virtual drive) + * - Page 83 Data (scsi page 83 guid) + * - Logical Sector Size (logical sector size in bytes, either 512 or + * 4096. We only support 512 currently) + * - Physical Sector Size (512 or 4096) + * + * Also, if the File Parameters indicate this is a differencing file, + * we must also look for the Parent Locator metadata item. + */ +static int vhdx_parse_metadata(BlockDriverState *bs, BDRVVHDXState *s) +{ + int ret = 0; + uint8_t *buffer; + int offset = 0; + uint32_t i = 0; + VHDXMetadataTableEntry md_entry; + + buffer = qemu_blockalign(bs, VHDX_METADATA_TABLE_MAX_SIZE); + + ret = bdrv_pread(bs->file, s->metadata_rt.file_offset, buffer, + VHDX_METADATA_TABLE_MAX_SIZE); + if (ret < 0) { + goto exit; + } + memcpy(&s->metadata_hdr, buffer, sizeof(s->metadata_hdr)); + offset += sizeof(s->metadata_hdr); + + le64_to_cpus(&s->metadata_hdr.signature); + le16_to_cpus(&s->metadata_hdr.reserved); + le16_to_cpus(&s->metadata_hdr.entry_count); + + if (memcmp(&s->metadata_hdr.signature, "metadata", 8)) { + ret = -EINVAL; + goto exit; + } + + s->metadata_entries.present = 0; + + if ((s->metadata_hdr.entry_count * sizeof(md_entry)) > + (VHDX_METADATA_TABLE_MAX_SIZE - offset)) { + ret = -EINVAL; + goto exit; + } + + for (i = 0; i < s->metadata_hdr.entry_count; i++) { + memcpy(&md_entry, buffer + offset, sizeof(md_entry)); + offset += sizeof(md_entry); + + leguid_to_cpus(&md_entry.item_id); + le32_to_cpus(&md_entry.offset); + le32_to_cpus(&md_entry.length); + le32_to_cpus(&md_entry.data_bits); + le32_to_cpus(&md_entry.reserved2); + + if (guid_eq(md_entry.item_id, file_param_guid)) { + if (s->metadata_entries.present & META_FILE_PARAMETER_PRESENT) { + ret = -EINVAL; + goto exit; + } + s->metadata_entries.file_parameters_entry = md_entry; + s->metadata_entries.present |= META_FILE_PARAMETER_PRESENT; + continue; + } + + if (guid_eq(md_entry.item_id, virtual_size_guid)) { + if (s->metadata_entries.present & META_VIRTUAL_DISK_SIZE_PRESENT) { + ret = -EINVAL; + goto exit; + } + s->metadata_entries.virtual_disk_size_entry = md_entry; + s->metadata_entries.present |= META_VIRTUAL_DISK_SIZE_PRESENT; + continue; + } + + if (guid_eq(md_entry.item_id, page83_guid)) { + if (s->metadata_entries.present & META_PAGE_83_PRESENT) { + ret = -EINVAL; + goto exit; + } + s->metadata_entries.page83_data_entry = md_entry; + s->metadata_entries.present |= META_PAGE_83_PRESENT; + continue; + } + + if (guid_eq(md_entry.item_id, logical_sector_guid)) { + if (s->metadata_entries.present & + META_LOGICAL_SECTOR_SIZE_PRESENT) { + ret = -EINVAL; + goto exit; + } + s->metadata_entries.logical_sector_size_entry = md_entry; + s->metadata_entries.present |= META_LOGICAL_SECTOR_SIZE_PRESENT; + continue; + } + + if (guid_eq(md_entry.item_id, phys_sector_guid)) { + if (s->metadata_entries.present & META_PHYS_SECTOR_SIZE_PRESENT) { + ret = -EINVAL; + goto exit; + } + s->metadata_entries.phys_sector_size_entry = md_entry; + s->metadata_entries.present |= META_PHYS_SECTOR_SIZE_PRESENT; + continue; + } + + if (guid_eq(md_entry.item_id, parent_locator_guid)) { + if (s->metadata_entries.present & META_PARENT_LOCATOR_PRESENT) { + ret = -EINVAL; + goto exit; + } + s->metadata_entries.parent_locator_entry = md_entry; + s->metadata_entries.present |= META_PARENT_LOCATOR_PRESENT; + continue; + } + + if (md_entry.data_bits & VHDX_META_FLAGS_IS_REQUIRED) { + /* cannot read vhdx file - required region table entry that + * we do not understand. per spec, we must fail to open */ + ret = -ENOTSUP; + goto exit; + } + } + + if (s->metadata_entries.present != META_ALL_PRESENT) { + ret = -ENOTSUP; + goto exit; + } + + ret = bdrv_pread(bs->file, + s->metadata_entries.file_parameters_entry.offset + + s->metadata_rt.file_offset, + &s->params, + sizeof(s->params)); + + if (ret < 0) { + goto exit; + } + + le32_to_cpus(&s->params.block_size); + le32_to_cpus(&s->params.data_bits); + + + /* We now have the file parameters, so we can tell if this is a + * differencing file (i.e.. has_parent), is dynamic or fixed + * sized (leave_blocks_allocated), and the block size */ + + /* The parent locator required iff the file parameters has_parent set */ + if (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) { + if (s->metadata_entries.present & META_PARENT_LOCATOR_PRESENT) { + /* TODO: parse parent locator fields */ + ret = -ENOTSUP; /* temp, until differencing files are supported */ + goto exit; + } else { + /* if has_parent is set, but there is not parent locator present, + * then that is an invalid combination */ + ret = -EINVAL; + goto exit; + } + } + + /* determine virtual disk size, logical sector size, + * and phys sector size */ + + ret = bdrv_pread(bs->file, + s->metadata_entries.virtual_disk_size_entry.offset + + s->metadata_rt.file_offset, + &s->virtual_disk_size, + sizeof(uint64_t)); + if (ret < 0) { + goto exit; + } + ret = bdrv_pread(bs->file, + s->metadata_entries.logical_sector_size_entry.offset + + s->metadata_rt.file_offset, + &s->logical_sector_size, + sizeof(uint32_t)); + if (ret < 0) { + goto exit; + } + ret = bdrv_pread(bs->file, + s->metadata_entries.phys_sector_size_entry.offset + + s->metadata_rt.file_offset, + &s->physical_sector_size, + sizeof(uint32_t)); + if (ret < 0) { + goto exit; + } + + le64_to_cpus(&s->virtual_disk_size); + le32_to_cpus(&s->logical_sector_size); + le32_to_cpus(&s->physical_sector_size); + + if (s->logical_sector_size == 0 || s->params.block_size == 0) { + ret = -EINVAL; + goto exit; + } + + /* both block_size and sector_size are guaranteed powers of 2 */ + s->sectors_per_block = s->params.block_size / s->logical_sector_size; + s->chunk_ratio = (VHDX_MAX_SECTORS_PER_BLOCK) * + (uint64_t)s->logical_sector_size / + (uint64_t)s->params.block_size; + + /* These values are ones we will want to use for division / multiplication + * later on, and they are all guaranteed (per the spec) to be powers of 2, + * so we can take advantage of that for shift operations during + * reads/writes */ + if (s->logical_sector_size & (s->logical_sector_size - 1)) { + ret = -EINVAL; + goto exit; + } + if (s->sectors_per_block & (s->sectors_per_block - 1)) { + ret = -EINVAL; + goto exit; + } + if (s->chunk_ratio & (s->chunk_ratio - 1)) { + ret = -EINVAL; + goto exit; + } + s->block_size = s->params.block_size; + if (s->block_size & (s->block_size - 1)) { + ret = -EINVAL; + goto exit; + } + + s->logical_sector_size_bits = 31 - clz32(s->logical_sector_size); + s->sectors_per_block_bits = 31 - clz32(s->sectors_per_block); + s->chunk_ratio_bits = 63 - clz64(s->chunk_ratio); + s->block_size_bits = 31 - clz32(s->block_size); + + ret = 0; + +exit: + qemu_vfree(buffer); + return ret; +} + +/* Parse the replay log. Per the VHDX spec, if the log is present + * it must be replayed prior to opening the file, even read-only. + * + * If read-only, we must replay the log in RAM (or refuse to open + * a dirty VHDX file read-only */ +static int vhdx_parse_log(BlockDriverState *bs, BDRVVHDXState *s) +{ + int ret = 0; + int i; + VHDXHeader *hdr; + + hdr = s->headers[s->curr_header]; + + /* either the log guid, or log length is zero, + * then a replay log is present */ + for (i = 0; i < sizeof(hdr->log_guid.data4); i++) { + ret |= hdr->log_guid.data4[i]; + } + if (hdr->log_guid.data1 == 0 && + hdr->log_guid.data2 == 0 && + hdr->log_guid.data3 == 0 && + ret == 0) { + goto exit; + } + + /* per spec, only log version of 0 is supported */ + if (hdr->log_version != 0) { + ret = -EINVAL; + goto exit; + } + + if (hdr->log_length == 0) { + goto exit; + } + + /* We currently do not support images with logs to replay */ + ret = -ENOTSUP; + +exit: + return ret; +} + + +static int vhdx_open(BlockDriverState *bs, QDict *options, int flags) +{ + BDRVVHDXState *s = bs->opaque; + int ret = 0; + uint32_t i; + uint64_t signature; + uint32_t data_blocks_cnt, bitmap_blocks_cnt; + + + s->bat = NULL; + + qemu_co_mutex_init(&s->lock); + + /* validate the file signature */ + ret = bdrv_pread(bs->file, 0, &signature, sizeof(uint64_t)); + if (ret < 0) { + goto fail; + } + if (memcmp(&signature, "vhdxfile", 8)) { + ret = -EINVAL; + goto fail; + } + + ret = vhdx_parse_header(bs, s); + if (ret) { + goto fail; + } + + ret = vhdx_parse_log(bs, s); + if (ret) { + goto fail; + } + + ret = vhdx_open_region_tables(bs, s); + if (ret) { + goto fail; + } + + ret = vhdx_parse_metadata(bs, s); + if (ret) { + goto fail; + } + s->block_size = s->params.block_size; + + /* the VHDX spec dictates that virtual_disk_size is always a multiple of + * logical_sector_size */ + bs->total_sectors = s->virtual_disk_size >> s->logical_sector_size_bits; + + data_blocks_cnt = s->virtual_disk_size >> s->block_size_bits; + if (s->virtual_disk_size - (data_blocks_cnt << s->block_size_bits)) { + data_blocks_cnt++; + } + bitmap_blocks_cnt = data_blocks_cnt >> s->chunk_ratio_bits; + if (data_blocks_cnt - (bitmap_blocks_cnt << s->chunk_ratio_bits)) { + bitmap_blocks_cnt++; + } + + if (s->parent_entries) { + s->bat_entries = bitmap_blocks_cnt * (s->chunk_ratio + 1); + } else { + s->bat_entries = data_blocks_cnt + + ((data_blocks_cnt - 1) >> s->chunk_ratio_bits); + } + + s->bat_offset = s->bat_rt.file_offset; + + if (s->bat_entries > s->bat_rt.length / sizeof(VHDXBatEntry)) { + /* BAT allocation is not large enough for all entries */ + ret = -EINVAL; + goto fail; + } + + s->bat = qemu_blockalign(bs, s->bat_rt.length); + + ret = bdrv_pread(bs->file, s->bat_offset, s->bat, s->bat_rt.length); + if (ret < 0) { + goto fail; + } + + for (i = 0; i < s->bat_entries; i++) { + le64_to_cpus(&s->bat[i]); + } + + if (flags & BDRV_O_RDWR) { + ret = -ENOTSUP; + goto fail; + } + + /* TODO: differencing files, write */ + + return 0; +fail: + qemu_vfree(s->headers[0]); + qemu_vfree(s->headers[1]); + qemu_vfree(s->bat); + qemu_vfree(s->parent_entries); + return ret; +} + +static int vhdx_reopen_prepare(BDRVReopenState *state, + BlockReopenQueue *queue, Error **errp) +{ + return 0; +} + + +/* + * Perform sector to block offset translations, to get various + * sector and file offsets into the image. See VHDXSectorInfo + */ +static void vhdx_block_translate(BDRVVHDXState *s, int64_t sector_num, + int nb_sectors, VHDXSectorInfo *sinfo) +{ + uint32_t block_offset; + + sinfo->bat_idx = sector_num >> s->sectors_per_block_bits; + /* effectively a modulo - this gives us the offset into the block + * (in sector sizes) for our sector number */ + block_offset = sector_num - (sinfo->bat_idx << s->sectors_per_block_bits); + /* the chunk ratio gives us the interleaving of the sector + * bitmaps, so we need to advance our page block index by the + * sector bitmaps entry number */ + sinfo->bat_idx += sinfo->bat_idx >> s->chunk_ratio_bits; + + /* the number of sectors we can read/write in this cycle */ + sinfo->sectors_avail = s->sectors_per_block - block_offset; + + sinfo->bytes_left = sinfo->sectors_avail << s->logical_sector_size_bits; + + if (sinfo->sectors_avail > nb_sectors) { + sinfo->sectors_avail = nb_sectors; + } + + sinfo->bytes_avail = sinfo->sectors_avail << s->logical_sector_size_bits; + + sinfo->file_offset = s->bat[sinfo->bat_idx] >> VHDX_BAT_FILE_OFF_BITS; + + sinfo->block_offset = block_offset << s->logical_sector_size_bits; + + /* The file offset must be past the header section, so must be > 0 */ + if (sinfo->file_offset == 0) { + return; + } + + /* block offset is the offset in vhdx logical sectors, in + * the payload data block. Convert that to a byte offset + * in the block, and add in the payload data block offset + * in the file, in bytes, to get the final read address */ + + sinfo->file_offset <<= 20; /* now in bytes, rather than 1MB units */ + sinfo->file_offset += sinfo->block_offset; +} + + + +static coroutine_fn int vhdx_co_readv(BlockDriverState *bs, int64_t sector_num, + int nb_sectors, QEMUIOVector *qiov) +{ + BDRVVHDXState *s = bs->opaque; + int ret = 0; + VHDXSectorInfo sinfo; + uint64_t bytes_done = 0; + QEMUIOVector hd_qiov; + + qemu_iovec_init(&hd_qiov, qiov->niov); + + qemu_co_mutex_lock(&s->lock); + + while (nb_sectors > 0) { + /* We are a differencing file, so we need to inspect the sector bitmap + * to see if we have the data or not */ + if (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) { + /* not supported yet */ + ret = -ENOTSUP; + goto exit; + } else { + vhdx_block_translate(s, sector_num, nb_sectors, &sinfo); + + qemu_iovec_reset(&hd_qiov); + qemu_iovec_concat(&hd_qiov, qiov, bytes_done, sinfo.bytes_avail); + + /* check the payload block state */ + switch (s->bat[sinfo.bat_idx] & VHDX_BAT_STATE_BIT_MASK) { + case PAYLOAD_BLOCK_NOT_PRESENT: /* fall through */ + case PAYLOAD_BLOCK_UNDEFINED: /* fall through */ + case PAYLOAD_BLOCK_UNMAPPED: /* fall through */ + case PAYLOAD_BLOCK_ZERO: + /* return zero */ + qemu_iovec_memset(&hd_qiov, 0, 0, sinfo.bytes_avail); + break; + case PAYLOAD_BLOCK_FULL_PRESENT: + qemu_co_mutex_unlock(&s->lock); + ret = bdrv_co_readv(bs->file, + sinfo.file_offset >> BDRV_SECTOR_BITS, + sinfo.sectors_avail, &hd_qiov); + qemu_co_mutex_lock(&s->lock); + if (ret < 0) { + goto exit; + } + break; + case PAYLOAD_BLOCK_PARTIALLY_PRESENT: + /* we don't yet support difference files, fall through + * to error */ + default: + ret = -EIO; + goto exit; + break; + } + nb_sectors -= sinfo.sectors_avail; + sector_num += sinfo.sectors_avail; + bytes_done += sinfo.bytes_avail; + } + } + ret = 0; +exit: + qemu_co_mutex_unlock(&s->lock); + qemu_iovec_destroy(&hd_qiov); + return ret; +} + + + +static coroutine_fn int vhdx_co_writev(BlockDriverState *bs, int64_t sector_num, + int nb_sectors, QEMUIOVector *qiov) +{ + return -ENOTSUP; +} + + +static void vhdx_close(BlockDriverState *bs) +{ + BDRVVHDXState *s = bs->opaque; + qemu_vfree(s->headers[0]); + qemu_vfree(s->headers[1]); + qemu_vfree(s->bat); + qemu_vfree(s->parent_entries); +} + +static BlockDriver bdrv_vhdx = { + .format_name = "vhdx", + .instance_size = sizeof(BDRVVHDXState), + .bdrv_probe = vhdx_probe, + .bdrv_open = vhdx_open, + .bdrv_close = vhdx_close, + .bdrv_reopen_prepare = vhdx_reopen_prepare, + .bdrv_co_readv = vhdx_co_readv, + .bdrv_co_writev = vhdx_co_writev, +}; + +static void bdrv_vhdx_init(void) +{ + bdrv_register(&bdrv_vhdx); +} + +block_init(bdrv_vhdx_init); |