| Message ID | f57fdf4c8563d591b0c4992151ebcd22abef5175.1366726446.git.jcody@redhat.com |
|---|---|
| State | New |
| Headers | show |
Am 23.04.2013 um 16:24 hat Jeff Cody geschrieben: > This is based on Microsoft's VHDX specification: > "VHDX Format Specification v0.95", published 4/12/2012 > https://www.microsoft.com/en-us/download/details.aspx?id=29681 > > These structures define the various header, metadata, and other > block structures defined in the VHDX specification. > > Signed-off-by: Jeff Cody <jcody@redhat.com> > --- > block/vhdx.h | 327 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 327 insertions(+) > create mode 100644 block/vhdx.h > > diff --git a/block/vhdx.h b/block/vhdx.h > new file mode 100644 > index 0000000..f5cf1ed > --- /dev/null > +++ b/block/vhdx.h > @@ -0,0 +1,327 @@ > +/* > + * 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. > + * > + */ > + > +#ifndef BLOCK_VHDX_H > +#define BLOCK_VHDX_H > + > +/* Structures and fields present in the VHDX file */ > + > +/* The header section has the following blocks, > + * each block is 64KB: > + * > + * _____________________________________________________________________________ > + * | File Id. | Header 1 | Header 2 | Region Table | Reserved (768KB) | > + * |----------|---------------|------------|--------------|--------------------| > + * | | | | | | > + * 0.........64KB...........128KB........192KB..........256KB................1MB > + */ > + > +#define VHDX_HEADER_BLOCK_SIZE (64*1024) > + > +#define VHDX_FILE_ID_OFFSET 0 > +#define VHDX_HEADER1_OFFSET (VHDX_HEADER_BLOCK_SIZE*1) > +#define VHDX_HEADER2_OFFSET (VHDX_HEADER_BLOCK_SIZE*2) > +#define VHDX_REGION_TABLE_OFFSET (VHDX_HEADER_BLOCK_SIZE*3) > + > + > +/* > + * A note on the use of MS-GUID fields. For more details on the GUID, > + * please see: https://en.wikipedia.org/wiki/Globally_unique_identifier. > + * > + * The VHDX specification only states that these are MS GUIDs, and which > + * bytes are data1-data4. It makes no mention of what algorithm should be used > + * to generate the GUID, nor what standard. However, looking at the specified > + * known GUID fields, it appears the GUIDs are: > + * Standard/DCE GUID type (noted by 10b in the MSB of byte 0 of .data4) > + * Random algorithm (noted by 0x4XXX for .data3) > + */ > + > +/* ---- HEADER SECTION STRUCTURES ---- */ > + > +/* Important note: these structures are as defined in the VHDX specification, > + * including byte order and size. However, without being packed structures, > + * they will not match 1:1 data read from disk. Rather than use potentially > + * non-portable packed structures, data is copied from read buffers into > + * the structures below. However, for reference, please refrain from > + * modifying these structures to something that does not represent the spec */ > + > +#define VHDX_FILE_ID_MAGIC 0x656C696678646876 /* 'vhdxfile' */ > +typedef struct vhdx_file_identifier { According to the qemu coding style, this is not a valid name for a struct. I think you can choose between VHDXFileIdentifier and VhdxFileIdentifier, where existing code tends towards the former. More instances of this follow, but I won't comment on each. > + uint64_t signature; /* "vhdxfile" in ASCII */ > + uint16_t creator[256]; /* optional; utf-16 string to identify > + the vhdx file creator. Diagnotistic > + only */ > +} vhdx_file_identifier; > + > + > +/* the guid is a 16 byte unique ID - the definition for this used by > + * Microsoft is not just 16 bytes though - it is a structure that is defined, > + * so we need to follow it here so that endianness does not trip us up */ > + > +typedef struct ms_guid { > + uint32_t data1; > + uint16_t data2; > + uint16_t data3; > + uint8_t data4[8]; > +} ms_guid; > + > +#define guid_eq(a, b) \ > + (memcmp(&(a), &(b), sizeof(ms_guid)) == 0) > + > +#define VHDX_HEADER_SIZE (4*1024) /* although the vhdx_header struct in disk > + is only 582 bytes, for purposes of crc > + the header is the first 4KB of the 64KB > + block */ > + > +#define VHDX_HDR_MAGIC 0x64616568 /* 'head' */ > +typedef struct QEMU_PACKED vhdx_header { > + uint32_t signature; /* "head" in ASCII */ > + uint32_t checksum; /* CRC-32C hash of the whole header */ > + uint64_t sequence_number; /* Seq number of this header. Each > + VHDX file has 2 of these headers, > + and only the header with the highest > + sequence number is valid */ > + ms_guid file_write_guid; /* 128 bit unique identifier. Must be > + updated to new, unique value before > + the first modification is made to > + file */ > + ms_guid data_write_guid; /* 128 bit unique identifier. Must be > + updated to new, unique value before > + the first modification is made to > + visible data. Visbile data is > + defined as: > + - system & user metadata > + - raw block data > + - disk size > + - any change that will > + cause the virtual disk > + sector read to differ > + > + This does not need to change if > + blocks are re-arranged */ > + ms_guid log_guid; /* 128 bit unique identifier. If zero, > + there is no valid log. If non-zero, > + log entries with this guid are > + valid. */ > + uint16_t log_version; /* version of the log format. Mustn't be > + zero, unless log_guid is also zero */ > + uint16_t version; /* version of th evhdx file. Currently, > + only supported version is "1" */ > + uint32_t log_length; /* length of the log. Must be multiple > + of 1MB */ > + uint64_t log_offset; /* byte offset in the file of the log. > + Must also be a multiple of 1MB */ > +} vhdx_header; > + > +/* 4KB in packed data size, not to be used except for initial data read */ > +typedef struct QEMU_PACKED vhdx_header_padded { > + vhdx_header header; > + uint8_t reserved[502]; /* per the VHDX spec */ > + uint8_t reserved_[3514]; /* for the initial packed struct read */ > +} vhdx_header_padded; > + > +/* Header for the region table block */ > +#define VHDX_RT_MAGIC 0x69676572 /* 'regi ' */ > +typedef struct QEMU_PACKED vhdx_region_table_header { > + uint32_t signature; /* "regi" in ASCII */ > + uint32_t checksum; /* CRC-32C hash of the 64KB table */ > + uint32_t entry_count; /* number of valid entries */ > + uint32_t reserved; > +} vhdx_region_table_header; > + > +/* Individual region table entry. There may be a maximum of 2047 of these > + * > + * There are two known region table properties. Both are required. > + * BAT (block allocation table): 2DC27766F62342009D64115E9BFD4A08 > + * Metadata: 8B7CA20647904B9AB8FE575F050F886E > + */ > +#define VHDX_REGION_ENTRY_REQUIRED 0x01 /* if set, parser must understand > + this entry in order to open > + file */ > +typedef struct QEMU_PACKED vhdx_region_table_entry { > + ms_guid guid; /* 128-bit unique identifier */ > + uint64_t file_offset; /* offset of the object in the file. > + Must be multiple of 1MB */ > + uint32_t length; /* length, in bytes, of the object */ > + uint32_t data_bits; > +} vhdx_region_table_entry; > + > + > +/* ---- LOG ENTRY STRUCTURES ---- */ > +#define VHDX_LOG_HDR_SIZE 64 > +#define VHDX_LOGE_MAGIC 0x65676F6C /* 'loge' */ > +typedef struct QEMU_PACKED vhdx_log_entry_header { > + uint32_t signature; /* "loge" in ASCII */ > + uint32_t checksum; /* CRC-32C hash of the 64KB table */ > + uint32_t entry_length; /* length in bytes, multiple of 1MB */ > + uint32_t tail; /* byte offset of first log entry of a > + seq, where this entry is the last > + entry */ > + uint64_t sequence_number; /* incremented with each log entry. > + May not be zero. */ > + uint32_t descriptor_count; /* number of descriptors in this log > + entry, must be >= 0 */ > + uint32_t reserved; > + ms_guid log_guid; /* value of the log_guid from > + vhdx_header. If not found in > + vhdx_header, it is invalid */ > + uint64_t flushed_file_offset; /* see spec for full details - this > + sould be vhdx file size in bytes */ > + uint64_t last_file_offset; /* size in bytes that all allocated > + file structures fit into */ > +} vhdx_log_entry_header; > + > +#define VHDX_LOG_DESC_SIZE 32 > + > +#define VHDX_ZERO_MAGIC 0x6F72657A /* 'zero' */ > +#define VHDX_DATA_MAGIC 0x63736564 /* 'desc' */ > +typedef struct QEMU_PACKED vhdx_log_descriptor { > + uint32_t signature; /* "zero" or "desc" in ASCII */ > + union { > + uint32_t reserved; /* zero desc */ > + uint32_t trailing_bytes; /* data desc: bytes 4092-4096 of the > + data sector */ > + }; Indentation inside the union is off. > + union { > + uint64_t zero_length; /* zero desc: length of the section to > + zero */ > + uint64_t leading_bytes; /* data desc: bytes 0-7 of the data > + sector */ > + }; Here as well. > + uint64_t file_offset; /* file offset to write zeros - multiple > + of 4kB */ > + uint64_t sequence_number; /* must match same field in > + vhdx_log_entry_header */ > +} vhdx_log_descriptor; > + > +#define VHDX_DATAS_MAGIC 0x61746164 /* 'data' */ > +typedef struct QEMU_PACKED vhdx_log_data_sector { > + uint32_t data_signature; /* "data" in ASCII */ > + uint32_t sequence_high; /* 4 MSB of 8 byte sequence_number */ > + uint8_t data[4084]; /* raw data, bytes 8-4091 (inclusive). > + see the data descriptor field for the > + other mising bytes */ > + uint32_t sequence_low; /* 4 LSB of 8 byte sequence_number */ > +} vhdx_log_data_sector; > + > + > + > +/* block states - different state values depending on whether it is a > + * payload block, or a sector block. */ > + > +#define PAYLOAD_BLOCK_NOT_PRESENT 0 > +#define PAYLOAD_BLOCK_UNDEFINED 1 > +#define PAYLOAD_BLOCK_ZERO 2 > +#define PAYLOAD_BLOCK_UNMAPPED 5 > +#define PAYLOAD_BLOCK_FULL_PRESENT 6 > +#define PAYLOAD_BLOCK_PARTIALLY_PRESENT 7 Looks like an enum? > +#define SB_BLOCK_NOT_PRESENT 0 > +#define SB_BLOCK_PRESENT 6 > + > +/* per the spec */ > +#define VHDX_MAX_SECTORS_PER_BLOCK (1<<23) > + > +/* upper 44 bits are the file offset in 1MB units lower 3 bits are the state > + other bits are reserved */ > +#define VHDX_BAT_STATE_BIT_MASK 0x07 > +#define VHDX_BAT_FILE_OFF_BITS (64-44) > +typedef uint64_t vhdx_bat_entry; > + > +/* ---- METADATA REGION STRUCTURES ---- */ > + > +#define VHDX_METADATA_ENTRY_SIZE 32 > +#define VHDX_METADATA_MAX_ENTRIES 2047 /* not including the header */ > +#define VHDX_METADATA_TABLE_MAX_SIZE \ > + (VHDX_METADATA_ENTRY_SIZE * (VHDX_METADATA_MAX_ENTRIES+1)) > +#define VHDX_METADATA_MAGIC 0x617461646174656D /* 'metadata' */ > +typedef struct QEMU_PACKED vhdx_metadata_table_header { > + uint64_t signature; /* "metadata" in ASCII */ > + uint16_t reserved; > + uint16_t entry_count; /* number table entries. <= 2047 */ > + uint32_t reserved2[5]; > +} vhdx_metadata_table_header; > + > +#define VHDX_META_FLAGS_IS_USER 0x01 /* max 1024 entries */ > +#define VHDX_META_FLAGS_IS_VIRTUAL_DISK 0x02 /* virtual disk metadata if set, > + otherwise file metdata */ > +#define VHDX_META_FLAGS_IS_REQUIRED 0x04 /* parse must understand this > + entry to open the file */ > +typedef struct QEMU_PACKED vhdx_metadata_table_entry { > + ms_guid item_id; /* 128-bit identifier for metadata */ > + uint32_t offset; /* byte offset of the metadata. At > + least 64kB. Relative to start of > + metadata region */ > + /* note: if length = 0, so is offset */ > + uint32_t length; /* length of metadata. <= 1MB. */ > + uint32_t data_bits; /* least-significant 3 bits are flags, the > + rest are reserved (see above) */ > + uint32_t reserved2; > +} vhdx_metadata_table_entry; > + > +#define VHDX_PARAMS_LEAVE_BLOCKS_ALLOCED 0x01 /* Do not change any blocks to > + be BLOCK_NOT_PRESENT. > + If set indicates a fixed > + size VHDX file */ > +#define VHDX_PARAMS_HAS_PARENT 0x02 /* has parent / backing file */ > +typedef struct QEMU_PACKED vhdx_file_parameters { > + uint32_t block_size; /* size of each payload block, always > + power of 2, <= 256MB and >= 1MB. */ > + uint32_t data_bits; /* least-significant 2 bits are flags, the rest > + are reserved (see above) */ > +} vhdx_file_parameters; > + > +typedef struct QEMU_PACKED vhdx_virtual_disk_size { > + uint64_t virtual_disk_size; /* Size of the virtual disk, in bytes. > + Must be multiple of the sector size, > + max of 64TB */ > +} vhdx_virtual_disk_size; > + > +typedef struct QEMU_PACKED vhdx_page83_data { > + uint8_t page_83_data[16]; /* unique id for scsi devices that > + support page 0x83 */ > +} vhdx_page83_data; > + > +typedef struct QEMU_PACKED vhdx_virtual_disk_logical_sector_size { > + uint32_t logical_sector_size; /* virtual disk sector size (in bytes). > + Can only be 512 or 4096 bytes */ > +} vhdx_virtual_disk_logical_sector_size; > + > +typedef struct QEMU_PACKED vhdx_virtual_disk_physical_sector_size { > + uint32_t physical_sector_size; /* physical sector size (in bytes). > + Can only be 512 or 4096 bytes */ > +} vhdx_virtual_disk_physical_sector_size; What's the point with all the single-field structs? > +typedef struct QEMU_PACKED vhdx_parent_locator_header { > + uint8_t locator_type[16]; /* type of the parent virtual disk. */ > + uint16_t reserved; > + uint16_t key_value_count; /* number of key/value pairs for this > + locator */ > +} vhdx_parent_locator_header; > + > +/* key and value strings are UNICODE strings, UTF-16 LE encoding, no NULs */ > +typedef struct QEMU_PACKED vhdx_parent_locator_entry { > + uint32_t key_offset; /* offset in metadata for key, > 0 */ > + uint32_t value_offset; /* offset in metadata for value, >0 */ > + uint16_t key_length; /* length of entry key, > 0 */ > + uint16_t value_length; /* length of entry value, > 0 */ > +} vhdx_parent_locator_entry; > + > + > +/* ----- END VHDX SPECIFICATION STRUCTURES ---- */ > + > +#endif Kevin
On Tue, Apr 23, 2013 at 05:10:18PM +0200, Kevin Wolf wrote: > Am 23.04.2013 um 16:24 hat Jeff Cody geschrieben: > > This is based on Microsoft's VHDX specification: > > "VHDX Format Specification v0.95", published 4/12/2012 > > https://www.microsoft.com/en-us/download/details.aspx?id=29681 > > > > These structures define the various header, metadata, and other > > block structures defined in the VHDX specification. > > > > Signed-off-by: Jeff Cody <jcody@redhat.com> > > --- > > block/vhdx.h | 327 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > 1 file changed, 327 insertions(+) > > create mode 100644 block/vhdx.h > > > > diff --git a/block/vhdx.h b/block/vhdx.h > > new file mode 100644 > > index 0000000..f5cf1ed > > --- /dev/null > > +++ b/block/vhdx.h > > @@ -0,0 +1,327 @@ > > +/* > > + * 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. > > + * > > + */ > > + > > +#ifndef BLOCK_VHDX_H > > +#define BLOCK_VHDX_H > > + > > +/* Structures and fields present in the VHDX file */ > > + > > +/* The header section has the following blocks, > > + * each block is 64KB: > > + * > > + * _____________________________________________________________________________ > > + * | File Id. | Header 1 | Header 2 | Region Table | Reserved (768KB) | > > + * |----------|---------------|------------|--------------|--------------------| > > + * | | | | | | > > + * 0.........64KB...........128KB........192KB..........256KB................1MB > > + */ > > + > > +#define VHDX_HEADER_BLOCK_SIZE (64*1024) > > + > > +#define VHDX_FILE_ID_OFFSET 0 > > +#define VHDX_HEADER1_OFFSET (VHDX_HEADER_BLOCK_SIZE*1) > > +#define VHDX_HEADER2_OFFSET (VHDX_HEADER_BLOCK_SIZE*2) > > +#define VHDX_REGION_TABLE_OFFSET (VHDX_HEADER_BLOCK_SIZE*3) > > + > > + > > +/* > > + * A note on the use of MS-GUID fields. For more details on the GUID, > > + * please see: https://en.wikipedia.org/wiki/Globally_unique_identifier. > > + * > > + * The VHDX specification only states that these are MS GUIDs, and which > > + * bytes are data1-data4. It makes no mention of what algorithm should be used > > + * to generate the GUID, nor what standard. However, looking at the specified > > + * known GUID fields, it appears the GUIDs are: > > + * Standard/DCE GUID type (noted by 10b in the MSB of byte 0 of .data4) > > + * Random algorithm (noted by 0x4XXX for .data3) > > + */ > > + > > +/* ---- HEADER SECTION STRUCTURES ---- */ > > + > > +/* Important note: these structures are as defined in the VHDX specification, > > + * including byte order and size. However, without being packed structures, > > + * they will not match 1:1 data read from disk. Rather than use potentially > > + * non-portable packed structures, data is copied from read buffers into > > + * the structures below. However, for reference, please refrain from > > + * modifying these structures to something that does not represent the spec */ > > + > > +#define VHDX_FILE_ID_MAGIC 0x656C696678646876 /* 'vhdxfile' */ > > +typedef struct vhdx_file_identifier { > > According to the qemu coding style, this is not a valid name for a > struct. I think you can choose between VHDXFileIdentifier and > VhdxFileIdentifier, where existing code tends towards the former. > > More instances of this follow, but I won't comment on each. > OK. I'll go through and change them all; almost all of them will need to be changed. > > + uint64_t signature; /* "vhdxfile" in ASCII */ > > + uint16_t creator[256]; /* optional; utf-16 string to identify > > + the vhdx file creator. Diagnotistic > > + only */ > > +} vhdx_file_identifier; > > + > > + > > +/* the guid is a 16 byte unique ID - the definition for this used by > > + * Microsoft is not just 16 bytes though - it is a structure that is defined, > > + * so we need to follow it here so that endianness does not trip us up */ > > + > > +typedef struct ms_guid { > > + uint32_t data1; > > + uint16_t data2; > > + uint16_t data3; > > + uint8_t data4[8]; > > +} ms_guid; > > + > > +#define guid_eq(a, b) \ > > + (memcmp(&(a), &(b), sizeof(ms_guid)) == 0) > > + > > +#define VHDX_HEADER_SIZE (4*1024) /* although the vhdx_header struct in disk > > + is only 582 bytes, for purposes of crc > > + the header is the first 4KB of the 64KB > > + block */ > > + > > +#define VHDX_HDR_MAGIC 0x64616568 /* 'head' */ > > +typedef struct QEMU_PACKED vhdx_header { > > + uint32_t signature; /* "head" in ASCII */ > > + uint32_t checksum; /* CRC-32C hash of the whole header */ > > + uint64_t sequence_number; /* Seq number of this header. Each > > + VHDX file has 2 of these headers, > > + and only the header with the highest > > + sequence number is valid */ > > + ms_guid file_write_guid; /* 128 bit unique identifier. Must be > > + updated to new, unique value before > > + the first modification is made to > > + file */ > > + ms_guid data_write_guid; /* 128 bit unique identifier. Must be > > + updated to new, unique value before > > + the first modification is made to > > + visible data. Visbile data is > > + defined as: > > + - system & user metadata > > + - raw block data > > + - disk size > > + - any change that will > > + cause the virtual disk > > + sector read to differ > > + > > + This does not need to change if > > + blocks are re-arranged */ > > + ms_guid log_guid; /* 128 bit unique identifier. If zero, > > + there is no valid log. If non-zero, > > + log entries with this guid are > > + valid. */ > > + uint16_t log_version; /* version of the log format. Mustn't be > > + zero, unless log_guid is also zero */ > > + uint16_t version; /* version of th evhdx file. Currently, > > + only supported version is "1" */ > > + uint32_t log_length; /* length of the log. Must be multiple > > + of 1MB */ > > + uint64_t log_offset; /* byte offset in the file of the log. > > + Must also be a multiple of 1MB */ > > +} vhdx_header; > > + > > +/* 4KB in packed data size, not to be used except for initial data read */ > > +typedef struct QEMU_PACKED vhdx_header_padded { > > + vhdx_header header; > > + uint8_t reserved[502]; /* per the VHDX spec */ > > + uint8_t reserved_[3514]; /* for the initial packed struct read */ > > +} vhdx_header_padded; > > + > > +/* Header for the region table block */ > > +#define VHDX_RT_MAGIC 0x69676572 /* 'regi ' */ > > +typedef struct QEMU_PACKED vhdx_region_table_header { > > + uint32_t signature; /* "regi" in ASCII */ > > + uint32_t checksum; /* CRC-32C hash of the 64KB table */ > > + uint32_t entry_count; /* number of valid entries */ > > + uint32_t reserved; > > +} vhdx_region_table_header; > > + > > +/* Individual region table entry. There may be a maximum of 2047 of these > > + * > > + * There are two known region table properties. Both are required. > > + * BAT (block allocation table): 2DC27766F62342009D64115E9BFD4A08 > > + * Metadata: 8B7CA20647904B9AB8FE575F050F886E > > + */ > > +#define VHDX_REGION_ENTRY_REQUIRED 0x01 /* if set, parser must understand > > + this entry in order to open > > + file */ > > +typedef struct QEMU_PACKED vhdx_region_table_entry { > > + ms_guid guid; /* 128-bit unique identifier */ > > + uint64_t file_offset; /* offset of the object in the file. > > + Must be multiple of 1MB */ > > + uint32_t length; /* length, in bytes, of the object */ > > + uint32_t data_bits; > > +} vhdx_region_table_entry; > > + > > + > > +/* ---- LOG ENTRY STRUCTURES ---- */ > > +#define VHDX_LOG_HDR_SIZE 64 > > +#define VHDX_LOGE_MAGIC 0x65676F6C /* 'loge' */ > > +typedef struct QEMU_PACKED vhdx_log_entry_header { > > + uint32_t signature; /* "loge" in ASCII */ > > + uint32_t checksum; /* CRC-32C hash of the 64KB table */ > > + uint32_t entry_length; /* length in bytes, multiple of 1MB */ > > + uint32_t tail; /* byte offset of first log entry of a > > + seq, where this entry is the last > > + entry */ > > + uint64_t sequence_number; /* incremented with each log entry. > > + May not be zero. */ > > + uint32_t descriptor_count; /* number of descriptors in this log > > + entry, must be >= 0 */ > > + uint32_t reserved; > > + ms_guid log_guid; /* value of the log_guid from > > + vhdx_header. If not found in > > + vhdx_header, it is invalid */ > > + uint64_t flushed_file_offset; /* see spec for full details - this > > + sould be vhdx file size in bytes */ > > + uint64_t last_file_offset; /* size in bytes that all allocated > > + file structures fit into */ > > +} vhdx_log_entry_header; > > + > > +#define VHDX_LOG_DESC_SIZE 32 > > + > > +#define VHDX_ZERO_MAGIC 0x6F72657A /* 'zero' */ > > +#define VHDX_DATA_MAGIC 0x63736564 /* 'desc' */ > > +typedef struct QEMU_PACKED vhdx_log_descriptor { > > + uint32_t signature; /* "zero" or "desc" in ASCII */ > > + union { > > + uint32_t reserved; /* zero desc */ > > + uint32_t trailing_bytes; /* data desc: bytes 4092-4096 of the > > + data sector */ > > + }; > > Indentation inside the union is off. > > > + union { > > + uint64_t zero_length; /* zero desc: length of the section to > > + zero */ > > + uint64_t leading_bytes; /* data desc: bytes 0-7 of the data > > + sector */ > > + }; > > Here as well. > OK, thanks. > > + uint64_t file_offset; /* file offset to write zeros - multiple > > + of 4kB */ > > + uint64_t sequence_number; /* must match same field in > > + vhdx_log_entry_header */ > > +} vhdx_log_descriptor; > > + > > +#define VHDX_DATAS_MAGIC 0x61746164 /* 'data' */ > > +typedef struct QEMU_PACKED vhdx_log_data_sector { > > + uint32_t data_signature; /* "data" in ASCII */ > > + uint32_t sequence_high; /* 4 MSB of 8 byte sequence_number */ > > + uint8_t data[4084]; /* raw data, bytes 8-4091 (inclusive). > > + see the data descriptor field for the > > + other mising bytes */ > > + uint32_t sequence_low; /* 4 LSB of 8 byte sequence_number */ > > +} vhdx_log_data_sector; > > + > > + > > + > > +/* block states - different state values depending on whether it is a > > + * payload block, or a sector block. */ > > + > > +#define PAYLOAD_BLOCK_NOT_PRESENT 0 > > +#define PAYLOAD_BLOCK_UNDEFINED 1 > > +#define PAYLOAD_BLOCK_ZERO 2 > > +#define PAYLOAD_BLOCK_UNMAPPED 5 > > +#define PAYLOAD_BLOCK_FULL_PRESENT 6 > > +#define PAYLOAD_BLOCK_PARTIALLY_PRESENT 7 > > Looks like an enum? > The spec lays them out as #define's, so this is a case where I figured it helped with a reader comparing against the spec. But I can make this (and the corresponding ones below) into enums, if you are worried about namespace pollution. > > +#define SB_BLOCK_NOT_PRESENT 0 > > +#define SB_BLOCK_PRESENT 6 > > + > > +/* per the spec */ > > +#define VHDX_MAX_SECTORS_PER_BLOCK (1<<23) > > + > > +/* upper 44 bits are the file offset in 1MB units lower 3 bits are the state > > + other bits are reserved */ > > +#define VHDX_BAT_STATE_BIT_MASK 0x07 > > +#define VHDX_BAT_FILE_OFF_BITS (64-44) > > +typedef uint64_t vhdx_bat_entry; > > + > > +/* ---- METADATA REGION STRUCTURES ---- */ > > + > > +#define VHDX_METADATA_ENTRY_SIZE 32 > > +#define VHDX_METADATA_MAX_ENTRIES 2047 /* not including the header */ > > +#define VHDX_METADATA_TABLE_MAX_SIZE \ > > + (VHDX_METADATA_ENTRY_SIZE * (VHDX_METADATA_MAX_ENTRIES+1)) > > +#define VHDX_METADATA_MAGIC 0x617461646174656D /* 'metadata' */ > > +typedef struct QEMU_PACKED vhdx_metadata_table_header { > > + uint64_t signature; /* "metadata" in ASCII */ > > + uint16_t reserved; > > + uint16_t entry_count; /* number table entries. <= 2047 */ > > + uint32_t reserved2[5]; > > +} vhdx_metadata_table_header; > > + > > +#define VHDX_META_FLAGS_IS_USER 0x01 /* max 1024 entries */ > > +#define VHDX_META_FLAGS_IS_VIRTUAL_DISK 0x02 /* virtual disk metadata if set, > > + otherwise file metdata */ > > +#define VHDX_META_FLAGS_IS_REQUIRED 0x04 /* parse must understand this > > + entry to open the file */ > > +typedef struct QEMU_PACKED vhdx_metadata_table_entry { > > + ms_guid item_id; /* 128-bit identifier for metadata */ > > + uint32_t offset; /* byte offset of the metadata. At > > + least 64kB. Relative to start of > > + metadata region */ > > + /* note: if length = 0, so is offset */ > > + uint32_t length; /* length of metadata. <= 1MB. */ > > + uint32_t data_bits; /* least-significant 3 bits are flags, the > > + rest are reserved (see above) */ > > + uint32_t reserved2; > > +} vhdx_metadata_table_entry; > > + > > +#define VHDX_PARAMS_LEAVE_BLOCKS_ALLOCED 0x01 /* Do not change any blocks to > > + be BLOCK_NOT_PRESENT. > > + If set indicates a fixed > > + size VHDX file */ > > +#define VHDX_PARAMS_HAS_PARENT 0x02 /* has parent / backing file */ > > +typedef struct QEMU_PACKED vhdx_file_parameters { > > + uint32_t block_size; /* size of each payload block, always > > + power of 2, <= 256MB and >= 1MB. */ > > + uint32_t data_bits; /* least-significant 2 bits are flags, the rest > > + are reserved (see above) */ > > +} vhdx_file_parameters; > > + > > +typedef struct QEMU_PACKED vhdx_virtual_disk_size { > > + uint64_t virtual_disk_size; /* Size of the virtual disk, in bytes. > > + Must be multiple of the sector size, > > + max of 64TB */ > > +} vhdx_virtual_disk_size; > > + > > +typedef struct QEMU_PACKED vhdx_page83_data { > > + uint8_t page_83_data[16]; /* unique id for scsi devices that > > + support page 0x83 */ > > +} vhdx_page83_data; > > + > > +typedef struct QEMU_PACKED vhdx_virtual_disk_logical_sector_size { > > + uint32_t logical_sector_size; /* virtual disk sector size (in bytes). > > + Can only be 512 or 4096 bytes */ > > +} vhdx_virtual_disk_logical_sector_size; > > + > > +typedef struct QEMU_PACKED vhdx_virtual_disk_physical_sector_size { > > + uint32_t physical_sector_size; /* physical sector size (in bytes). > > + Can only be 512 or 4096 bytes */ > > +} vhdx_virtual_disk_physical_sector_size; > > What's the point with all the single-field structs? > Another case of laying out as it was in the spec, for readability. I tried to keep the header as faithful to the spec as possible; if you have a strong preference, I can drop these and just use the single field types inside vhdx.c. > > +typedef struct QEMU_PACKED vhdx_parent_locator_header { > > + uint8_t locator_type[16]; /* type of the parent virtual disk. */ > > + uint16_t reserved; > > + uint16_t key_value_count; /* number of key/value pairs for this > > + locator */ > > +} vhdx_parent_locator_header; > > + > > +/* key and value strings are UNICODE strings, UTF-16 LE encoding, no NULs */ > > +typedef struct QEMU_PACKED vhdx_parent_locator_entry { > > + uint32_t key_offset; /* offset in metadata for key, > 0 */ > > + uint32_t value_offset; /* offset in metadata for value, >0 */ > > + uint16_t key_length; /* length of entry key, > 0 */ > > + uint16_t value_length; /* length of entry value, > 0 */ > > +} vhdx_parent_locator_entry; > > + > > + > > +/* ----- END VHDX SPECIFICATION STRUCTURES ---- */ > > + > > +#endif > > Kevin
On Tue, Apr 23, 2013 at 10:24:21AM -0400, Jeff Cody wrote: > +/* ---- HEADER SECTION STRUCTURES ---- */ > + > +/* Important note: these structures are as defined in the VHDX specification, > + * including byte order and size. However, without being packed structures, > + * they will not match 1:1 data read from disk. Rather than use potentially > + * non-portable packed structures, data is copied from read buffers into > + * the structures below. However, for reference, please refrain from > + * modifying these structures to something that does not represent the spec */ Outdated comment? The patch uses QEMU_PACKED. > +/* Header for the region table block */ > +#define VHDX_RT_MAGIC 0x69676572 /* 'regi ' */ Not worth respinnning, but should be 'regi' (4 bytes).
On Wed, Apr 24, 2013 at 02:31:27PM +0200, Stefan Hajnoczi wrote: > On Tue, Apr 23, 2013 at 10:24:21AM -0400, Jeff Cody wrote: > > +/* ---- HEADER SECTION STRUCTURES ---- */ > > + > > +/* Important note: these structures are as defined in the VHDX specification, > > + * including byte order and size. However, without being packed structures, > > + * they will not match 1:1 data read from disk. Rather than use potentially > > + * non-portable packed structures, data is copied from read buffers into > > + * the structures below. However, for reference, please refrain from > > + * modifying these structures to something that does not represent the spec */ > > Outdated comment? The patch uses QEMU_PACKED. > Yes, outdated comment, thanks. > > +/* Header for the region table block */ > > +#define VHDX_RT_MAGIC 0x69676572 /* 'regi ' */ > > Not worth respinnning, but should be 'regi' (4 bytes). Per Kevin's comments, I am removing all the _MAGIC's from the headers anyway, and using memcmp against the strings in the source file. So I'll take care of the outdated comment as well then.
Am 23.04.2013 um 16:24 hat Jeff Cody geschrieben: > This is based on Microsoft's VHDX specification: > "VHDX Format Specification v0.95", published 4/12/2012 > https://www.microsoft.com/en-us/download/details.aspx?id=29681 > > These structures define the various header, metadata, and other > block structures defined in the VHDX specification. > > Signed-off-by: Jeff Cody <jcody@redhat.com> > --- > block/vhdx.h | 327 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 327 insertions(+) > create mode 100644 block/vhdx.h > +typedef struct QEMU_PACKED vhdx_page83_data { > + uint8_t page_83_data[16]; /* unique id for scsi devices that > + support page 0x83 */ > +} vhdx_page83_data; Why uint8_t[16] instead of ms_guid? > + > +typedef struct QEMU_PACKED vhdx_virtual_disk_logical_sector_size { > + uint32_t logical_sector_size; /* virtual disk sector size (in bytes). > + Can only be 512 or 4096 bytes */ > +} vhdx_virtual_disk_logical_sector_size; > + > +typedef struct QEMU_PACKED vhdx_virtual_disk_physical_sector_size { > + uint32_t physical_sector_size; /* physical sector size (in bytes). > + Can only be 512 or 4096 bytes */ > +} vhdx_virtual_disk_physical_sector_size; > + > +typedef struct QEMU_PACKED vhdx_parent_locator_header { > + uint8_t locator_type[16]; /* type of the parent virtual disk. */ Same question here. > + uint16_t reserved; > + uint16_t key_value_count; /* number of key/value pairs for this > + locator */ > +} vhdx_parent_locator_header; Kevin
On Thu, Apr 25, 2013 at 03:05:37PM +0200, Kevin Wolf wrote: > Am 23.04.2013 um 16:24 hat Jeff Cody geschrieben: > > This is based on Microsoft's VHDX specification: > > "VHDX Format Specification v0.95", published 4/12/2012 > > https://www.microsoft.com/en-us/download/details.aspx?id=29681 > > > > These structures define the various header, metadata, and other > > block structures defined in the VHDX specification. > > > > Signed-off-by: Jeff Cody <jcody@redhat.com> > > --- > > block/vhdx.h | 327 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > 1 file changed, 327 insertions(+) > > create mode 100644 block/vhdx.h > > > +typedef struct QEMU_PACKED vhdx_page83_data { > > + uint8_t page_83_data[16]; /* unique id for scsi devices that > > + support page 0x83 */ > > +} vhdx_page83_data; > > Why uint8_t[16] instead of ms_guid? > > > + > > +typedef struct QEMU_PACKED vhdx_virtual_disk_logical_sector_size { > > + uint32_t logical_sector_size; /* virtual disk sector size (in bytes). > > + Can only be 512 or 4096 bytes */ > > +} vhdx_virtual_disk_logical_sector_size; > > + > > +typedef struct QEMU_PACKED vhdx_virtual_disk_physical_sector_size { > > + uint32_t physical_sector_size; /* physical sector size (in bytes). > > + Can only be 512 or 4096 bytes */ > > +} vhdx_virtual_disk_physical_sector_size; > > + > > +typedef struct QEMU_PACKED vhdx_parent_locator_header { > > + uint8_t locator_type[16]; /* type of the parent virtual disk. */ > > Same question here. > You are right, those should both be ms_guid. > > + uint16_t reserved; > > + uint16_t key_value_count; /* number of key/value pairs for this > > + locator */ > > +} vhdx_parent_locator_header; > > Kevin
diff --git a/block/vhdx.h b/block/vhdx.h new file mode 100644 index 0000000..f5cf1ed --- /dev/null +++ b/block/vhdx.h @@ -0,0 +1,327 @@ +/* + * 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. + * + */ + +#ifndef BLOCK_VHDX_H +#define BLOCK_VHDX_H + +/* Structures and fields present in the VHDX file */ + +/* The header section has the following blocks, + * each block is 64KB: + * + * _____________________________________________________________________________ + * | File Id. | Header 1 | Header 2 | Region Table | Reserved (768KB) | + * |----------|---------------|------------|--------------|--------------------| + * | | | | | | + * 0.........64KB...........128KB........192KB..........256KB................1MB + */ + +#define VHDX_HEADER_BLOCK_SIZE (64*1024) + +#define VHDX_FILE_ID_OFFSET 0 +#define VHDX_HEADER1_OFFSET (VHDX_HEADER_BLOCK_SIZE*1) +#define VHDX_HEADER2_OFFSET (VHDX_HEADER_BLOCK_SIZE*2) +#define VHDX_REGION_TABLE_OFFSET (VHDX_HEADER_BLOCK_SIZE*3) + + +/* + * A note on the use of MS-GUID fields. For more details on the GUID, + * please see: https://en.wikipedia.org/wiki/Globally_unique_identifier. + * + * The VHDX specification only states that these are MS GUIDs, and which + * bytes are data1-data4. It makes no mention of what algorithm should be used + * to generate the GUID, nor what standard. However, looking at the specified + * known GUID fields, it appears the GUIDs are: + * Standard/DCE GUID type (noted by 10b in the MSB of byte 0 of .data4) + * Random algorithm (noted by 0x4XXX for .data3) + */ + +/* ---- HEADER SECTION STRUCTURES ---- */ + +/* Important note: these structures are as defined in the VHDX specification, + * including byte order and size. However, without being packed structures, + * they will not match 1:1 data read from disk. Rather than use potentially + * non-portable packed structures, data is copied from read buffers into + * the structures below. However, for reference, please refrain from + * modifying these structures to something that does not represent the spec */ + +#define VHDX_FILE_ID_MAGIC 0x656C696678646876 /* 'vhdxfile' */ +typedef struct vhdx_file_identifier { + uint64_t signature; /* "vhdxfile" in ASCII */ + uint16_t creator[256]; /* optional; utf-16 string to identify + the vhdx file creator. Diagnotistic + only */ +} vhdx_file_identifier; + + +/* the guid is a 16 byte unique ID - the definition for this used by + * Microsoft is not just 16 bytes though - it is a structure that is defined, + * so we need to follow it here so that endianness does not trip us up */ + +typedef struct ms_guid { + uint32_t data1; + uint16_t data2; + uint16_t data3; + uint8_t data4[8]; +} ms_guid; + +#define guid_eq(a, b) \ + (memcmp(&(a), &(b), sizeof(ms_guid)) == 0) + +#define VHDX_HEADER_SIZE (4*1024) /* although the vhdx_header struct in disk + is only 582 bytes, for purposes of crc + the header is the first 4KB of the 64KB + block */ + +#define VHDX_HDR_MAGIC 0x64616568 /* 'head' */ +typedef struct QEMU_PACKED vhdx_header { + uint32_t signature; /* "head" in ASCII */ + uint32_t checksum; /* CRC-32C hash of the whole header */ + uint64_t sequence_number; /* Seq number of this header. Each + VHDX file has 2 of these headers, + and only the header with the highest + sequence number is valid */ + ms_guid file_write_guid; /* 128 bit unique identifier. Must be + updated to new, unique value before + the first modification is made to + file */ + ms_guid data_write_guid; /* 128 bit unique identifier. Must be + updated to new, unique value before + the first modification is made to + visible data. Visbile data is + defined as: + - system & user metadata + - raw block data + - disk size + - any change that will + cause the virtual disk + sector read to differ + + This does not need to change if + blocks are re-arranged */ + ms_guid log_guid; /* 128 bit unique identifier. If zero, + there is no valid log. If non-zero, + log entries with this guid are + valid. */ + uint16_t log_version; /* version of the log format. Mustn't be + zero, unless log_guid is also zero */ + uint16_t version; /* version of th evhdx file. Currently, + only supported version is "1" */ + uint32_t log_length; /* length of the log. Must be multiple + of 1MB */ + uint64_t log_offset; /* byte offset in the file of the log. + Must also be a multiple of 1MB */ +} vhdx_header; + +/* 4KB in packed data size, not to be used except for initial data read */ +typedef struct QEMU_PACKED vhdx_header_padded { + vhdx_header header; + uint8_t reserved[502]; /* per the VHDX spec */ + uint8_t reserved_[3514]; /* for the initial packed struct read */ +} vhdx_header_padded; + +/* Header for the region table block */ +#define VHDX_RT_MAGIC 0x69676572 /* 'regi ' */ +typedef struct QEMU_PACKED vhdx_region_table_header { + uint32_t signature; /* "regi" in ASCII */ + uint32_t checksum; /* CRC-32C hash of the 64KB table */ + uint32_t entry_count; /* number of valid entries */ + uint32_t reserved; +} vhdx_region_table_header; + +/* Individual region table entry. There may be a maximum of 2047 of these + * + * There are two known region table properties. Both are required. + * BAT (block allocation table): 2DC27766F62342009D64115E9BFD4A08 + * Metadata: 8B7CA20647904B9AB8FE575F050F886E + */ +#define VHDX_REGION_ENTRY_REQUIRED 0x01 /* if set, parser must understand + this entry in order to open + file */ +typedef struct QEMU_PACKED vhdx_region_table_entry { + ms_guid guid; /* 128-bit unique identifier */ + uint64_t file_offset; /* offset of the object in the file. + Must be multiple of 1MB */ + uint32_t length; /* length, in bytes, of the object */ + uint32_t data_bits; +} vhdx_region_table_entry; + + +/* ---- LOG ENTRY STRUCTURES ---- */ +#define VHDX_LOG_HDR_SIZE 64 +#define VHDX_LOGE_MAGIC 0x65676F6C /* 'loge' */ +typedef struct QEMU_PACKED vhdx_log_entry_header { + uint32_t signature; /* "loge" in ASCII */ + uint32_t checksum; /* CRC-32C hash of the 64KB table */ + uint32_t entry_length; /* length in bytes, multiple of 1MB */ + uint32_t tail; /* byte offset of first log entry of a + seq, where this entry is the last + entry */ + uint64_t sequence_number; /* incremented with each log entry. + May not be zero. */ + uint32_t descriptor_count; /* number of descriptors in this log + entry, must be >= 0 */ + uint32_t reserved; + ms_guid log_guid; /* value of the log_guid from + vhdx_header. If not found in + vhdx_header, it is invalid */ + uint64_t flushed_file_offset; /* see spec for full details - this + sould be vhdx file size in bytes */ + uint64_t last_file_offset; /* size in bytes that all allocated + file structures fit into */ +} vhdx_log_entry_header; + +#define VHDX_LOG_DESC_SIZE 32 + +#define VHDX_ZERO_MAGIC 0x6F72657A /* 'zero' */ +#define VHDX_DATA_MAGIC 0x63736564 /* 'desc' */ +typedef struct QEMU_PACKED vhdx_log_descriptor { + uint32_t signature; /* "zero" or "desc" in ASCII */ + union { + uint32_t reserved; /* zero desc */ + uint32_t trailing_bytes; /* data desc: bytes 4092-4096 of the + data sector */ + }; + union { + uint64_t zero_length; /* zero desc: length of the section to + zero */ + uint64_t leading_bytes; /* data desc: bytes 0-7 of the data + sector */ + }; + uint64_t file_offset; /* file offset to write zeros - multiple + of 4kB */ + uint64_t sequence_number; /* must match same field in + vhdx_log_entry_header */ +} vhdx_log_descriptor; + +#define VHDX_DATAS_MAGIC 0x61746164 /* 'data' */ +typedef struct QEMU_PACKED vhdx_log_data_sector { + uint32_t data_signature; /* "data" in ASCII */ + uint32_t sequence_high; /* 4 MSB of 8 byte sequence_number */ + uint8_t data[4084]; /* raw data, bytes 8-4091 (inclusive). + see the data descriptor field for the + other mising bytes */ + uint32_t sequence_low; /* 4 LSB of 8 byte sequence_number */ +} vhdx_log_data_sector; + + + +/* block states - different state values depending on whether it is a + * payload block, or a sector block. */ + +#define PAYLOAD_BLOCK_NOT_PRESENT 0 +#define PAYLOAD_BLOCK_UNDEFINED 1 +#define PAYLOAD_BLOCK_ZERO 2 +#define PAYLOAD_BLOCK_UNMAPPED 5 +#define PAYLOAD_BLOCK_FULL_PRESENT 6 +#define PAYLOAD_BLOCK_PARTIALLY_PRESENT 7 + +#define SB_BLOCK_NOT_PRESENT 0 +#define SB_BLOCK_PRESENT 6 + +/* per the spec */ +#define VHDX_MAX_SECTORS_PER_BLOCK (1<<23) + +/* upper 44 bits are the file offset in 1MB units lower 3 bits are the state + other bits are reserved */ +#define VHDX_BAT_STATE_BIT_MASK 0x07 +#define VHDX_BAT_FILE_OFF_BITS (64-44) +typedef uint64_t vhdx_bat_entry; + +/* ---- METADATA REGION STRUCTURES ---- */ + +#define VHDX_METADATA_ENTRY_SIZE 32 +#define VHDX_METADATA_MAX_ENTRIES 2047 /* not including the header */ +#define VHDX_METADATA_TABLE_MAX_SIZE \ + (VHDX_METADATA_ENTRY_SIZE * (VHDX_METADATA_MAX_ENTRIES+1)) +#define VHDX_METADATA_MAGIC 0x617461646174656D /* 'metadata' */ +typedef struct QEMU_PACKED vhdx_metadata_table_header { + uint64_t signature; /* "metadata" in ASCII */ + uint16_t reserved; + uint16_t entry_count; /* number table entries. <= 2047 */ + uint32_t reserved2[5]; +} vhdx_metadata_table_header; + +#define VHDX_META_FLAGS_IS_USER 0x01 /* max 1024 entries */ +#define VHDX_META_FLAGS_IS_VIRTUAL_DISK 0x02 /* virtual disk metadata if set, + otherwise file metdata */ +#define VHDX_META_FLAGS_IS_REQUIRED 0x04 /* parse must understand this + entry to open the file */ +typedef struct QEMU_PACKED vhdx_metadata_table_entry { + ms_guid item_id; /* 128-bit identifier for metadata */ + uint32_t offset; /* byte offset of the metadata. At + least 64kB. Relative to start of + metadata region */ + /* note: if length = 0, so is offset */ + uint32_t length; /* length of metadata. <= 1MB. */ + uint32_t data_bits; /* least-significant 3 bits are flags, the + rest are reserved (see above) */ + uint32_t reserved2; +} vhdx_metadata_table_entry; + +#define VHDX_PARAMS_LEAVE_BLOCKS_ALLOCED 0x01 /* Do not change any blocks to + be BLOCK_NOT_PRESENT. + If set indicates a fixed + size VHDX file */ +#define VHDX_PARAMS_HAS_PARENT 0x02 /* has parent / backing file */ +typedef struct QEMU_PACKED vhdx_file_parameters { + uint32_t block_size; /* size of each payload block, always + power of 2, <= 256MB and >= 1MB. */ + uint32_t data_bits; /* least-significant 2 bits are flags, the rest + are reserved (see above) */ +} vhdx_file_parameters; + +typedef struct QEMU_PACKED vhdx_virtual_disk_size { + uint64_t virtual_disk_size; /* Size of the virtual disk, in bytes. + Must be multiple of the sector size, + max of 64TB */ +} vhdx_virtual_disk_size; + +typedef struct QEMU_PACKED vhdx_page83_data { + uint8_t page_83_data[16]; /* unique id for scsi devices that + support page 0x83 */ +} vhdx_page83_data; + +typedef struct QEMU_PACKED vhdx_virtual_disk_logical_sector_size { + uint32_t logical_sector_size; /* virtual disk sector size (in bytes). + Can only be 512 or 4096 bytes */ +} vhdx_virtual_disk_logical_sector_size; + +typedef struct QEMU_PACKED vhdx_virtual_disk_physical_sector_size { + uint32_t physical_sector_size; /* physical sector size (in bytes). + Can only be 512 or 4096 bytes */ +} vhdx_virtual_disk_physical_sector_size; + +typedef struct QEMU_PACKED vhdx_parent_locator_header { + uint8_t locator_type[16]; /* type of the parent virtual disk. */ + uint16_t reserved; + uint16_t key_value_count; /* number of key/value pairs for this + locator */ +} vhdx_parent_locator_header; + +/* key and value strings are UNICODE strings, UTF-16 LE encoding, no NULs */ +typedef struct QEMU_PACKED vhdx_parent_locator_entry { + uint32_t key_offset; /* offset in metadata for key, > 0 */ + uint32_t value_offset; /* offset in metadata for value, >0 */ + uint16_t key_length; /* length of entry key, > 0 */ + uint16_t value_length; /* length of entry value, > 0 */ +} vhdx_parent_locator_entry; + + +/* ----- END VHDX SPECIFICATION STRUCTURES ---- */ + +#endif
This is based on Microsoft's VHDX specification: "VHDX Format Specification v0.95", published 4/12/2012 https://www.microsoft.com/en-us/download/details.aspx?id=29681 These structures define the various header, metadata, and other block structures defined in the VHDX specification. Signed-off-by: Jeff Cody <jcody@redhat.com> --- block/vhdx.h | 327 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 327 insertions(+) create mode 100644 block/vhdx.h