--- /dev/null
+/*
+ * 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 v1.00", published 8/25/2012
+ * by Microsoft:
+ * https://www.microsoft.com/en-us/download/details.aspx?id=34750
+ *
+ * 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
+
+#define KiB (1 * 1024)
+#define MiB (KiB * 1024)
+#define GiB (MiB * 1024)
+#define TiB ((uint64_t) GiB * 1024)
+
+#define DEFAULT_LOG_SIZE 1048576 /* 1MiB */
+/* 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)
+#define VHDX_REGION_TABLE2_OFFSET (VHDX_HEADER_BLOCK_SIZE * 4)
+
+#define VHDX_HEADER_SECTION_END (1 * MiB)
+/*
+ * 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 */
+
+#define VHDX_FILE_SIGNATURE 0x656C696678646876ULL /* "vhdxfile" in ASCII */
+typedef struct VHDXFileIdentifier {
+ uint64_t signature; /* "vhdxfile" in ASCII */
+ uint16_t creator[256]; /* optional; utf-16 string to identify
+ the vhdx file creator. Diagnostic
+ 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 QEMU_PACKED 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 */
+#define VHDX_HEADER_SIGNATURE 0x64616568
+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. Must be
+ set to zero */
+ uint16_t version; /* version of the vhdx 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 */
+#define VHDX_REGION_SIGNATURE 0x69676572 /* "regi" in ASCII */
+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_MIN_SIZE (1024 * 1024)
+#define VHDX_LOG_SECTOR_SIZE 4096
+#define VHDX_LOG_HDR_SIZE 64
+#define VHDX_LOG_SIGNATURE 0x65676f6c
+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
+ should 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
+#define VHDX_LOG_DESC_SIGNATURE 0x63736564
+#define VHDX_LOG_ZERO_SIGNATURE 0x6f72657a
+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;
+
+#define VHDX_LOG_DATA_SIGNATURE 0x61746164
+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 3
+#define PAYLOAD_BLOCK_UNMAPPED_v095 5
+#define PAYLOAD_BLOCK_FULLY_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_MASK 0xFFFFFFFFFFF00000ULL /* upper 44 bits */
+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))
+#define VHDX_METADATA_SIGNATURE 0x617461646174656DULL /* "metadata" in ASCII */
+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 */
+#define VHDX_BLOCK_SIZE_MIN (1 * MiB)
+#define VHDX_BLOCK_SIZE_MAX (256 * MiB)
+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;
+
+#define VHDX_MAX_IMAGE_SIZE ((uint64_t) 64 * TiB)
+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; /* 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; /* 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 ---- */
+
+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 VHDXLogEntries {
+ uint64_t offset;
+ uint64_t length;
+ uint32_t write;
+ uint32_t read;
+ VHDXLogEntryHeader *hdr;
+ void *desc_buffer;
+ uint64_t sequence;
+ uint32_t tail;
+} VHDXLogEntries;
+
+typedef struct VHDXRegionEntry {
+ uint64_t start;
+ uint64_t end;
+ QLIST_ENTRY(VHDXRegionEntry) entries;
+} VHDXRegionEntry;
+
+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;
+
+ bool first_visible_write;
+ MSGUID session_guid;
+
+ VHDXLogEntries log;
+
+ VHDXParentLocatorHeader parent_header;
+ VHDXParentLocatorEntry *parent_entries;
+
+ Error *migration_blocker;
+
+ bool log_replayed_on_open;
+
+ QLIST_HEAD(VHDXRegionHead, VHDXRegionEntry) regions;
+} BDRVVHDXState;
+
+void vhdx_guid_generate(MSGUID *guid);
+
+int vhdx_update_headers(BlockDriverState *bs, BDRVVHDXState *s, bool rw,
+ MSGUID *log_guid);
+
+uint32_t vhdx_update_checksum(uint8_t *buf, size_t size, int crc_offset);
+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);
+
+int vhdx_parse_log(BlockDriverState *bs, BDRVVHDXState *s, bool *flushed,
+ Error **errp);
+
+int vhdx_log_write_and_flush(BlockDriverState *bs, BDRVVHDXState *s,
+ void *data, uint32_t length, uint64_t offset);
+
+static inline void leguid_to_cpus(MSGUID *guid)
+{
+ le32_to_cpus(&guid->data1);
+ le16_to_cpus(&guid->data2);
+ le16_to_cpus(&guid->data3);
+}
+
+static inline void cpu_to_leguids(MSGUID *guid)
+{
+ cpu_to_le32s(&guid->data1);
+ cpu_to_le16s(&guid->data2);
+ cpu_to_le16s(&guid->data3);
+}
+
+void vhdx_header_le_import(VHDXHeader *h);
+void vhdx_header_le_export(VHDXHeader *orig_h, VHDXHeader *new_h);
+void vhdx_log_desc_le_import(VHDXLogDescriptor *d);
+void vhdx_log_desc_le_export(VHDXLogDescriptor *d);
+void vhdx_log_data_le_import(VHDXLogDataSector *d);
+void vhdx_log_data_le_export(VHDXLogDataSector *d);
+void vhdx_log_entry_hdr_le_import(VHDXLogEntryHeader *hdr);
+void vhdx_log_entry_hdr_le_export(VHDXLogEntryHeader *hdr);
+void vhdx_region_header_le_import(VHDXRegionTableHeader *hdr);
+void vhdx_region_header_le_export(VHDXRegionTableHeader *hdr);
+void vhdx_region_entry_le_import(VHDXRegionTableEntry *e);
+void vhdx_region_entry_le_export(VHDXRegionTableEntry *e);
+void vhdx_metadata_header_le_import(VHDXMetadataTableHeader *hdr);
+void vhdx_metadata_header_le_export(VHDXMetadataTableHeader *hdr);
+void vhdx_metadata_entry_le_import(VHDXMetadataTableEntry *e);
+void vhdx_metadata_entry_le_export(VHDXMetadataTableEntry *e);
+int vhdx_user_visible_write(BlockDriverState *bs, BDRVVHDXState *s);
+
+#endif
Code Review / kvmfornfv.git / blobdiff