mirror of https://gitee.com/openkylin/qemu.git
326 lines
15 KiB
C
326 lines
15 KiB
C
/*
|
|
* 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 ---- */
|
|
|
|
/* These structures are ones that are defined in the VHDX specification
|
|
* document */
|
|
|
|
typedef struct VHDXFileIdentifier {
|
|
uint64_t signature; /* "vhdxfile" in ASCII */
|
|
uint16_t creator[256]; /* optional; utf-16 string to identify
|
|
the vhdx file creator. Diagnotistic
|
|
only */
|
|
} VHDXFileIdentifier;
|
|
|
|
|
|
/* 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 MSGUID {
|
|
uint32_t data1;
|
|
uint16_t data2;
|
|
uint16_t data3;
|
|
uint8_t data4[8];
|
|
} MSGUID;
|
|
|
|
#define guid_eq(a, b) \
|
|
(memcmp(&(a), &(b), sizeof(MSGUID)) == 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 */
|
|
|
|
/* The full header is 4KB, although the actual header data is much smaller.
|
|
* But for the checksum calculation, it is over the entire 4KB structure,
|
|
* not just the defined portion of it */
|
|
typedef struct QEMU_PACKED VHDXHeader {
|
|
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 */
|
|
MSGUID file_write_guid; /* 128 bit unique identifier. Must be
|
|
updated to new, unique value before
|
|
the first modification is made to
|
|
file */
|
|
MSGUID 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 */
|
|
MSGUID 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 */
|
|
} VHDXHeader;
|
|
|
|
/* Header for the region table block */
|
|
typedef struct QEMU_PACKED VHDXRegionTableHeader {
|
|
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;
|
|
} VHDXRegionTableHeader;
|
|
|
|
/* 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 VHDXRegionTableEntry {
|
|
MSGUID 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;
|
|
} VHDXRegionTableEntry;
|
|
|
|
|
|
/* ---- LOG ENTRY STRUCTURES ---- */
|
|
#define VHDX_LOG_HDR_SIZE 64
|
|
typedef struct QEMU_PACKED VHDXLogEntryHeader {
|
|
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;
|
|
MSGUID 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 */
|
|
} VHDXLogEntryHeader;
|
|
|
|
#define VHDX_LOG_DESC_SIZE 32
|
|
|
|
typedef struct QEMU_PACKED VHDXLogDescriptor {
|
|
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 */
|
|
} VHDXLogDescriptor;
|
|
|
|
typedef struct QEMU_PACKED VHDXLogDataSector {
|
|
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 */
|
|
} VHDXLogDataSector;
|
|
|
|
|
|
|
|
/* 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 VHDXBatEntry;
|
|
|
|
/* ---- 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))
|
|
typedef struct QEMU_PACKED VHDXMetadataTableHeader {
|
|
uint64_t signature; /* "metadata" in ASCII */
|
|
uint16_t reserved;
|
|
uint16_t entry_count; /* number table entries. <= 2047 */
|
|
uint32_t reserved2[5];
|
|
} VHDXMetadataTableHeader;
|
|
|
|
#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 VHDXMetadataTableEntry {
|
|
MSGUID 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;
|
|
} VHDXMetadataTableEntry;
|
|
|
|
#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 VHDXFileParameters {
|
|
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) */
|
|
} VHDXFileParameters;
|
|
|
|
typedef struct QEMU_PACKED VHDXVirtualDiskSize {
|
|
uint64_t virtual_disk_size; /* Size of the virtual disk, in bytes.
|
|
Must be multiple of the sector size,
|
|
max of 64TB */
|
|
} VHDXVirtualDiskSize;
|
|
|
|
typedef struct QEMU_PACKED VHDXPage83Data {
|
|
MSGUID page_83_data[16]; /* unique id for scsi devices that
|
|
support page 0x83 */
|
|
} VHDXPage83Data;
|
|
|
|
typedef struct QEMU_PACKED VHDXVirtualDiskLogicalSectorSize {
|
|
uint32_t logical_sector_size; /* virtual disk sector size (in bytes).
|
|
Can only be 512 or 4096 bytes */
|
|
} VHDXVirtualDiskLogicalSectorSize;
|
|
|
|
typedef struct QEMU_PACKED VHDXVirtualDiskPhysicalSectorSize {
|
|
uint32_t physical_sector_size; /* physical sector size (in bytes).
|
|
Can only be 512 or 4096 bytes */
|
|
} VHDXVirtualDiskPhysicalSectorSize;
|
|
|
|
typedef struct QEMU_PACKED VHDXParentLocatorHeader {
|
|
MSGUID 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 */
|
|
} VHDXParentLocatorHeader;
|
|
|
|
/* key and value strings are UNICODE strings, UTF-16 LE encoding, no NULs */
|
|
typedef struct QEMU_PACKED VHDXParentLocatorEntry {
|
|
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 */
|
|
} VHDXParentLocatorEntry;
|
|
|
|
|
|
/* ----- END VHDX SPECIFICATION STRUCTURES ---- */
|
|
|
|
|
|
uint32_t vhdx_checksum_calc(uint32_t crc, uint8_t *buf, size_t size,
|
|
int crc_offset);
|
|
|
|
bool vhdx_checksum_is_valid(uint8_t *buf, size_t size, int crc_offset);
|
|
|
|
|
|
static void leguid_to_cpus(MSGUID *guid)
|
|
{
|
|
le32_to_cpus(&guid->data1);
|
|
le16_to_cpus(&guid->data2);
|
|
le16_to_cpus(&guid->data3);
|
|
}
|
|
|
|
#endif
|