Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging
[qemu.git] / block / vhdx.h
1 /*
2 * Block driver for Hyper-V VHDX Images
3 *
4 * Copyright (c) 2013 Red Hat, Inc.,
5 *
6 * Authors:
7 * Jeff Cody <jcody@redhat.com>
8 *
9 * This is based on the "VHDX Format Specification v1.00", published 8/25/2012
10 * by Microsoft:
11 * https://www.microsoft.com/en-us/download/details.aspx?id=34750
12 *
13 * This work is licensed under the terms of the GNU LGPL, version 2 or later.
14 * See the COPYING.LIB file in the top-level directory.
15 *
16 */
17
18 #ifndef BLOCK_VHDX_H
19 #define BLOCK_VHDX_H
20
21 #define KiB (1 * 1024)
22 #define MiB (KiB * 1024)
23 #define GiB (MiB * 1024)
24 #define TiB ((uint64_t) GiB * 1024)
25
26 /* Structures and fields present in the VHDX file */
27
28 /* The header section has the following blocks,
29 * each block is 64KB:
30 *
31 * _____________________________________________________________________________
32 * | File Id. | Header 1 | Header 2 | Region Table | Reserved (768KB) |
33 * |----------|---------------|------------|--------------|--------------------|
34 * | | | | | |
35 * 0.........64KB...........128KB........192KB..........256KB................1MB
36 */
37
38 #define VHDX_HEADER_BLOCK_SIZE (64 * 1024)
39
40 #define VHDX_FILE_ID_OFFSET 0
41 #define VHDX_HEADER1_OFFSET (VHDX_HEADER_BLOCK_SIZE * 1)
42 #define VHDX_HEADER2_OFFSET (VHDX_HEADER_BLOCK_SIZE * 2)
43 #define VHDX_REGION_TABLE_OFFSET (VHDX_HEADER_BLOCK_SIZE * 3)
44 #define VHDX_REGION_TABLE2_OFFSET (VHDX_HEADER_BLOCK_SIZE * 4)
45
46 #define VHDX_HEADER_SECTION_END (1 * MiB)
47 /*
48 * A note on the use of MS-GUID fields. For more details on the GUID,
49 * please see: https://en.wikipedia.org/wiki/Globally_unique_identifier.
50 *
51 * The VHDX specification only states that these are MS GUIDs, and which
52 * bytes are data1-data4. It makes no mention of what algorithm should be used
53 * to generate the GUID, nor what standard. However, looking at the specified
54 * known GUID fields, it appears the GUIDs are:
55 * Standard/DCE GUID type (noted by 10b in the MSB of byte 0 of .data4)
56 * Random algorithm (noted by 0x4XXX for .data3)
57 */
58
59 /* ---- HEADER SECTION STRUCTURES ---- */
60
61 /* These structures are ones that are defined in the VHDX specification
62 * document */
63
64 #define VHDX_FILE_SIGNATURE 0x656C696678646876ULL /* "vhdxfile" in ASCII */
65 typedef struct VHDXFileIdentifier {
66 uint64_t signature; /* "vhdxfile" in ASCII */
67 uint16_t creator[256]; /* optional; utf-16 string to identify
68 the vhdx file creator. Diagnostic
69 only */
70 } VHDXFileIdentifier;
71
72
73 /* the guid is a 16 byte unique ID - the definition for this used by
74 * Microsoft is not just 16 bytes though - it is a structure that is defined,
75 * so we need to follow it here so that endianness does not trip us up */
76
77 typedef struct QEMU_PACKED MSGUID {
78 uint32_t data1;
79 uint16_t data2;
80 uint16_t data3;
81 uint8_t data4[8];
82 } MSGUID;
83
84 #define guid_eq(a, b) \
85 (memcmp(&(a), &(b), sizeof(MSGUID)) == 0)
86
87 #define VHDX_HEADER_SIZE (4 * 1024) /* although the vhdx_header struct in disk
88 is only 582 bytes, for purposes of crc
89 the header is the first 4KB of the 64KB
90 block */
91
92 /* The full header is 4KB, although the actual header data is much smaller.
93 * But for the checksum calculation, it is over the entire 4KB structure,
94 * not just the defined portion of it */
95 #define VHDX_HEADER_SIGNATURE 0x64616568
96 typedef struct QEMU_PACKED VHDXHeader {
97 uint32_t signature; /* "head" in ASCII */
98 uint32_t checksum; /* CRC-32C hash of the whole header */
99 uint64_t sequence_number; /* Seq number of this header. Each
100 VHDX file has 2 of these headers,
101 and only the header with the highest
102 sequence number is valid */
103 MSGUID file_write_guid; /* 128 bit unique identifier. Must be
104 updated to new, unique value before
105 the first modification is made to
106 file */
107 MSGUID data_write_guid; /* 128 bit unique identifier. Must be
108 updated to new, unique value before
109 the first modification is made to
110 visible data. Visbile data is
111 defined as:
112 - system & user metadata
113 - raw block data
114 - disk size
115 - any change that will
116 cause the virtual disk
117 sector read to differ
118
119 This does not need to change if
120 blocks are re-arranged */
121 MSGUID log_guid; /* 128 bit unique identifier. If zero,
122 there is no valid log. If non-zero,
123 log entries with this guid are
124 valid. */
125 uint16_t log_version; /* version of the log format. Must be
126 set to zero */
127 uint16_t version; /* version of the vhdx file. Currently,
128 only supported version is "1" */
129 uint32_t log_length; /* length of the log. Must be multiple
130 of 1MB */
131 uint64_t log_offset; /* byte offset in the file of the log.
132 Must also be a multiple of 1MB */
133 } VHDXHeader;
134
135 /* Header for the region table block */
136 #define VHDX_REGION_SIGNATURE 0x69676572 /* "regi" in ASCII */
137 typedef struct QEMU_PACKED VHDXRegionTableHeader {
138 uint32_t signature; /* "regi" in ASCII */
139 uint32_t checksum; /* CRC-32C hash of the 64KB table */
140 uint32_t entry_count; /* number of valid entries */
141 uint32_t reserved;
142 } VHDXRegionTableHeader;
143
144 /* Individual region table entry. There may be a maximum of 2047 of these
145 *
146 * There are two known region table properties. Both are required.
147 * BAT (block allocation table): 2DC27766F62342009D64115E9BFD4A08
148 * Metadata: 8B7CA20647904B9AB8FE575F050F886E
149 */
150 #define VHDX_REGION_ENTRY_REQUIRED 0x01 /* if set, parser must understand
151 this entry in order to open
152 file */
153 typedef struct QEMU_PACKED VHDXRegionTableEntry {
154 MSGUID guid; /* 128-bit unique identifier */
155 uint64_t file_offset; /* offset of the object in the file.
156 Must be multiple of 1MB */
157 uint32_t length; /* length, in bytes, of the object */
158 uint32_t data_bits;
159 } VHDXRegionTableEntry;
160
161
162 /* ---- LOG ENTRY STRUCTURES ---- */
163 #define VHDX_LOG_MIN_SIZE (1024 * 1024)
164 #define VHDX_LOG_SECTOR_SIZE 4096
165 #define VHDX_LOG_HDR_SIZE 64
166 #define VHDX_LOG_SIGNATURE 0x65676f6c
167 typedef struct QEMU_PACKED VHDXLogEntryHeader {
168 uint32_t signature; /* "loge" in ASCII */
169 uint32_t checksum; /* CRC-32C hash of the 64KB table */
170 uint32_t entry_length; /* length in bytes, multiple of 1MB */
171 uint32_t tail; /* byte offset of first log entry of a
172 seq, where this entry is the last
173 entry */
174 uint64_t sequence_number; /* incremented with each log entry.
175 May not be zero. */
176 uint32_t descriptor_count; /* number of descriptors in this log
177 entry, must be >= 0 */
178 uint32_t reserved;
179 MSGUID log_guid; /* value of the log_guid from
180 vhdx_header. If not found in
181 vhdx_header, it is invalid */
182 uint64_t flushed_file_offset; /* see spec for full details - this
183 should be vhdx file size in bytes */
184 uint64_t last_file_offset; /* size in bytes that all allocated
185 file structures fit into */
186 } VHDXLogEntryHeader;
187
188 #define VHDX_LOG_DESC_SIZE 32
189 #define VHDX_LOG_DESC_SIGNATURE 0x63736564
190 #define VHDX_LOG_ZERO_SIGNATURE 0x6f72657a
191 typedef struct QEMU_PACKED VHDXLogDescriptor {
192 uint32_t signature; /* "zero" or "desc" in ASCII */
193 union {
194 uint32_t reserved; /* zero desc */
195 uint32_t trailing_bytes; /* data desc: bytes 4092-4096 of the
196 data sector */
197 };
198 union {
199 uint64_t zero_length; /* zero desc: length of the section to
200 zero */
201 uint64_t leading_bytes; /* data desc: bytes 0-7 of the data
202 sector */
203 };
204 uint64_t file_offset; /* file offset to write zeros - multiple
205 of 4kB */
206 uint64_t sequence_number; /* must match same field in
207 vhdx_log_entry_header */
208 } VHDXLogDescriptor;
209
210 #define VHDX_LOG_DATA_SIGNATURE 0x61746164
211 typedef struct QEMU_PACKED VHDXLogDataSector {
212 uint32_t data_signature; /* "data" in ASCII */
213 uint32_t sequence_high; /* 4 MSB of 8 byte sequence_number */
214 uint8_t data[4084]; /* raw data, bytes 8-4091 (inclusive).
215 see the data descriptor field for the
216 other mising bytes */
217 uint32_t sequence_low; /* 4 LSB of 8 byte sequence_number */
218 } VHDXLogDataSector;
219
220
221
222 /* block states - different state values depending on whether it is a
223 * payload block, or a sector block. */
224
225 #define PAYLOAD_BLOCK_NOT_PRESENT 0
226 #define PAYLOAD_BLOCK_UNDEFINED 1
227 #define PAYLOAD_BLOCK_ZERO 2
228 #define PAYLOAD_BLOCK_UNMAPPED 5
229 #define PAYLOAD_BLOCK_FULLY_PRESENT 6
230 #define PAYLOAD_BLOCK_PARTIALLY_PRESENT 7
231
232 #define SB_BLOCK_NOT_PRESENT 0
233 #define SB_BLOCK_PRESENT 6
234
235 /* per the spec */
236 #define VHDX_MAX_SECTORS_PER_BLOCK (1 << 23)
237
238 /* upper 44 bits are the file offset in 1MB units lower 3 bits are the state
239 other bits are reserved */
240 #define VHDX_BAT_STATE_BIT_MASK 0x07
241 #define VHDX_BAT_FILE_OFF_MASK 0xFFFFFFFFFFF00000ULL /* upper 44 bits */
242 typedef uint64_t VHDXBatEntry;
243
244 /* ---- METADATA REGION STRUCTURES ---- */
245
246 #define VHDX_METADATA_ENTRY_SIZE 32
247 #define VHDX_METADATA_MAX_ENTRIES 2047 /* not including the header */
248 #define VHDX_METADATA_TABLE_MAX_SIZE \
249 (VHDX_METADATA_ENTRY_SIZE * (VHDX_METADATA_MAX_ENTRIES+1))
250 #define VHDX_METADATA_SIGNATURE 0x617461646174656DULL /* "metadata" in ASCII */
251 typedef struct QEMU_PACKED VHDXMetadataTableHeader {
252 uint64_t signature; /* "metadata" in ASCII */
253 uint16_t reserved;
254 uint16_t entry_count; /* number table entries. <= 2047 */
255 uint32_t reserved2[5];
256 } VHDXMetadataTableHeader;
257
258 #define VHDX_META_FLAGS_IS_USER 0x01 /* max 1024 entries */
259 #define VHDX_META_FLAGS_IS_VIRTUAL_DISK 0x02 /* virtual disk metadata if set,
260 otherwise file metdata */
261 #define VHDX_META_FLAGS_IS_REQUIRED 0x04 /* parse must understand this
262 entry to open the file */
263 typedef struct QEMU_PACKED VHDXMetadataTableEntry {
264 MSGUID item_id; /* 128-bit identifier for metadata */
265 uint32_t offset; /* byte offset of the metadata. At
266 least 64kB. Relative to start of
267 metadata region */
268 /* note: if length = 0, so is offset */
269 uint32_t length; /* length of metadata. <= 1MB. */
270 uint32_t data_bits; /* least-significant 3 bits are flags,
271 the rest are reserved (see above) */
272 uint32_t reserved2;
273 } VHDXMetadataTableEntry;
274
275 #define VHDX_PARAMS_LEAVE_BLOCKS_ALLOCED 0x01 /* Do not change any blocks to
276 be BLOCK_NOT_PRESENT.
277 If set indicates a fixed
278 size VHDX file */
279 #define VHDX_PARAMS_HAS_PARENT 0x02 /* has parent / backing file */
280 #define VHDX_BLOCK_SIZE_MIN (1 * MiB)
281 #define VHDX_BLOCK_SIZE_MAX (256 * MiB)
282 typedef struct QEMU_PACKED VHDXFileParameters {
283 uint32_t block_size; /* size of each payload block, always
284 power of 2, <= 256MB and >= 1MB. */
285 uint32_t data_bits; /* least-significant 2 bits are flags,
286 the rest are reserved (see above) */
287 } VHDXFileParameters;
288
289 #define VHDX_MAX_IMAGE_SIZE ((uint64_t) 64 * TiB)
290 typedef struct QEMU_PACKED VHDXVirtualDiskSize {
291 uint64_t virtual_disk_size; /* Size of the virtual disk, in bytes.
292 Must be multiple of the sector size,
293 max of 64TB */
294 } VHDXVirtualDiskSize;
295
296 typedef struct QEMU_PACKED VHDXPage83Data {
297 MSGUID page_83_data; /* unique id for scsi devices that
298 support page 0x83 */
299 } VHDXPage83Data;
300
301 typedef struct QEMU_PACKED VHDXVirtualDiskLogicalSectorSize {
302 uint32_t logical_sector_size; /* virtual disk sector size (in bytes).
303 Can only be 512 or 4096 bytes */
304 } VHDXVirtualDiskLogicalSectorSize;
305
306 typedef struct QEMU_PACKED VHDXVirtualDiskPhysicalSectorSize {
307 uint32_t physical_sector_size; /* physical sector size (in bytes).
308 Can only be 512 or 4096 bytes */
309 } VHDXVirtualDiskPhysicalSectorSize;
310
311 typedef struct QEMU_PACKED VHDXParentLocatorHeader {
312 MSGUID locator_type; /* type of the parent virtual disk. */
313 uint16_t reserved;
314 uint16_t key_value_count; /* number of key/value pairs for this
315 locator */
316 } VHDXParentLocatorHeader;
317
318 /* key and value strings are UNICODE strings, UTF-16 LE encoding, no NULs */
319 typedef struct QEMU_PACKED VHDXParentLocatorEntry {
320 uint32_t key_offset; /* offset in metadata for key, > 0 */
321 uint32_t value_offset; /* offset in metadata for value, >0 */
322 uint16_t key_length; /* length of entry key, > 0 */
323 uint16_t value_length; /* length of entry value, > 0 */
324 } VHDXParentLocatorEntry;
325
326
327 /* ----- END VHDX SPECIFICATION STRUCTURES ---- */
328
329 typedef struct VHDXMetadataEntries {
330 VHDXMetadataTableEntry file_parameters_entry;
331 VHDXMetadataTableEntry virtual_disk_size_entry;
332 VHDXMetadataTableEntry page83_data_entry;
333 VHDXMetadataTableEntry logical_sector_size_entry;
334 VHDXMetadataTableEntry phys_sector_size_entry;
335 VHDXMetadataTableEntry parent_locator_entry;
336 uint16_t present;
337 } VHDXMetadataEntries;
338
339 typedef struct VHDXLogEntries {
340 uint64_t offset;
341 uint64_t length;
342 uint32_t write;
343 uint32_t read;
344 VHDXLogEntryHeader *hdr;
345 void *desc_buffer;
346 uint64_t sequence;
347 uint32_t tail;
348 } VHDXLogEntries;
349
350 typedef struct VHDXRegionEntry {
351 uint64_t start;
352 uint64_t end;
353 QLIST_ENTRY(VHDXRegionEntry) entries;
354 } VHDXRegionEntry;
355
356 typedef struct BDRVVHDXState {
357 CoMutex lock;
358
359 int curr_header;
360 VHDXHeader *headers[2];
361
362 VHDXRegionTableHeader rt;
363 VHDXRegionTableEntry bat_rt; /* region table for the BAT */
364 VHDXRegionTableEntry metadata_rt; /* region table for the metadata */
365
366 VHDXMetadataTableHeader metadata_hdr;
367 VHDXMetadataEntries metadata_entries;
368
369 VHDXFileParameters params;
370 uint32_t block_size;
371 uint32_t block_size_bits;
372 uint32_t sectors_per_block;
373 uint32_t sectors_per_block_bits;
374
375 uint64_t virtual_disk_size;
376 uint32_t logical_sector_size;
377 uint32_t physical_sector_size;
378
379 uint64_t chunk_ratio;
380 uint32_t chunk_ratio_bits;
381 uint32_t logical_sector_size_bits;
382
383 uint32_t bat_entries;
384 VHDXBatEntry *bat;
385 uint64_t bat_offset;
386
387 bool first_visible_write;
388 MSGUID session_guid;
389
390 VHDXLogEntries log;
391
392 VHDXParentLocatorHeader parent_header;
393 VHDXParentLocatorEntry *parent_entries;
394
395 Error *migration_blocker;
396
397 bool log_replayed_on_open;
398
399 QLIST_HEAD(VHDXRegionHead, VHDXRegionEntry) regions;
400 } BDRVVHDXState;
401
402 void vhdx_guid_generate(MSGUID *guid);
403
404 int vhdx_update_headers(BlockDriverState *bs, BDRVVHDXState *s, bool rw,
405 MSGUID *log_guid);
406
407 uint32_t vhdx_update_checksum(uint8_t *buf, size_t size, int crc_offset);
408 uint32_t vhdx_checksum_calc(uint32_t crc, uint8_t *buf, size_t size,
409 int crc_offset);
410
411 bool vhdx_checksum_is_valid(uint8_t *buf, size_t size, int crc_offset);
412
413 int vhdx_parse_log(BlockDriverState *bs, BDRVVHDXState *s, bool *flushed,
414 Error **errp);
415
416 int vhdx_log_write_and_flush(BlockDriverState *bs, BDRVVHDXState *s,
417 void *data, uint32_t length, uint64_t offset);
418
419 static inline void leguid_to_cpus(MSGUID *guid)
420 {
421 le32_to_cpus(&guid->data1);
422 le16_to_cpus(&guid->data2);
423 le16_to_cpus(&guid->data3);
424 }
425
426 static inline void cpu_to_leguids(MSGUID *guid)
427 {
428 cpu_to_le32s(&guid->data1);
429 cpu_to_le16s(&guid->data2);
430 cpu_to_le16s(&guid->data3);
431 }
432
433 void vhdx_header_le_import(VHDXHeader *h);
434 void vhdx_header_le_export(VHDXHeader *orig_h, VHDXHeader *new_h);
435 void vhdx_log_desc_le_import(VHDXLogDescriptor *d);
436 void vhdx_log_desc_le_export(VHDXLogDescriptor *d);
437 void vhdx_log_data_le_export(VHDXLogDataSector *d);
438 void vhdx_log_entry_hdr_le_import(VHDXLogEntryHeader *hdr);
439 void vhdx_log_entry_hdr_le_export(VHDXLogEntryHeader *hdr);
440 void vhdx_region_header_le_import(VHDXRegionTableHeader *hdr);
441 void vhdx_region_header_le_export(VHDXRegionTableHeader *hdr);
442 void vhdx_region_entry_le_import(VHDXRegionTableEntry *e);
443 void vhdx_region_entry_le_export(VHDXRegionTableEntry *e);
444 void vhdx_metadata_header_le_import(VHDXMetadataTableHeader *hdr);
445 void vhdx_metadata_header_le_export(VHDXMetadataTableHeader *hdr);
446 void vhdx_metadata_entry_le_import(VHDXMetadataTableEntry *e);
447 void vhdx_metadata_entry_le_export(VHDXMetadataTableEntry *e);
448 int vhdx_user_visible_write(BlockDriverState *bs, BDRVVHDXState *s);
449
450 #endif