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 #include "qemu/osdep.h"
19 #include "qapi/error.h"
20 #include "block/block_int.h"
21 #include "block/qdict.h"
22 #include "sysemu/block-backend.h"
23 #include "qemu/module.h"
24 #include "qemu/option.h"
25 #include "qemu/crc32c.h"
26 #include "qemu/bswap.h"
27 #include "qemu/error-report.h"
28 #include "qemu/memalign.h"
29 #include "vhdx.h"
30 #include "migration/blocker.h"
31 #include "qemu/uuid.h"
32 #include "qapi/qmp/qdict.h"
33 #include "qapi/qobject-input-visitor.h"
34 #include "qapi/qapi-visit-block-core.h"
35
36 /* Options for VHDX creation */
37
38 #define VHDX_BLOCK_OPT_LOG_SIZE "log_size"
39 #define VHDX_BLOCK_OPT_BLOCK_SIZE "block_size"
40 #define VHDX_BLOCK_OPT_ZERO "block_state_zero"
41
42 typedef enum VHDXImageType {
43 VHDX_TYPE_DYNAMIC = 0,
44 VHDX_TYPE_FIXED,
45 VHDX_TYPE_DIFFERENCING, /* Currently unsupported */
46 } VHDXImageType;
47
48 static QemuOptsList vhdx_create_opts;
49
50 /* Several metadata and region table data entries are identified by
51 * guids in a MS-specific GUID format. */
52
53
54 /* ------- Known Region Table GUIDs ---------------------- */
55 static const MSGUID bat_guid = { .data1 = 0x2dc27766,
56 .data2 = 0xf623,
57 .data3 = 0x4200,
58 .data4 = { 0x9d, 0x64, 0x11, 0x5e,
59 0x9b, 0xfd, 0x4a, 0x08} };
60
61 static const MSGUID metadata_guid = { .data1 = 0x8b7ca206,
62 .data2 = 0x4790,
63 .data3 = 0x4b9a,
64 .data4 = { 0xb8, 0xfe, 0x57, 0x5f,
65 0x05, 0x0f, 0x88, 0x6e} };
66
67
68
69 /* ------- Known Metadata Entry GUIDs ---------------------- */
70 static const MSGUID file_param_guid = { .data1 = 0xcaa16737,
71 .data2 = 0xfa36,
72 .data3 = 0x4d43,
73 .data4 = { 0xb3, 0xb6, 0x33, 0xf0,
74 0xaa, 0x44, 0xe7, 0x6b} };
75
76 static const MSGUID virtual_size_guid = { .data1 = 0x2FA54224,
77 .data2 = 0xcd1b,
78 .data3 = 0x4876,
79 .data4 = { 0xb2, 0x11, 0x5d, 0xbe,
80 0xd8, 0x3b, 0xf4, 0xb8} };
81
82 static const MSGUID page83_guid = { .data1 = 0xbeca12ab,
83 .data2 = 0xb2e6,
84 .data3 = 0x4523,
85 .data4 = { 0x93, 0xef, 0xc3, 0x09,
86 0xe0, 0x00, 0xc7, 0x46} };
87
88
89 static const MSGUID phys_sector_guid = { .data1 = 0xcda348c7,
90 .data2 = 0x445d,
91 .data3 = 0x4471,
92 .data4 = { 0x9c, 0xc9, 0xe9, 0x88,
93 0x52, 0x51, 0xc5, 0x56} };
94
95 static const MSGUID parent_locator_guid = { .data1 = 0xa8d35f2d,
96 .data2 = 0xb30b,
97 .data3 = 0x454d,
98 .data4 = { 0xab, 0xf7, 0xd3,
99 0xd8, 0x48, 0x34,
100 0xab, 0x0c} };
101
102 static const MSGUID logical_sector_guid = { .data1 = 0x8141bf1d,
103 .data2 = 0xa96f,
104 .data3 = 0x4709,
105 .data4 = { 0xba, 0x47, 0xf2,
106 0x33, 0xa8, 0xfa,
107 0xab, 0x5f} };
108
109 /* Each parent type must have a valid GUID; this is for parent images
110 * of type 'VHDX'. If we were to allow e.g. a QCOW2 parent, we would
111 * need to make up our own QCOW2 GUID type */
112 static const MSGUID parent_vhdx_guid __attribute__((unused))
113 = { .data1 = 0xb04aefb7,
114 .data2 = 0xd19e,
115 .data3 = 0x4a81,
116 .data4 = { 0xb7, 0x89, 0x25, 0xb8,
117 0xe9, 0x44, 0x59, 0x13} };
118
119
120 #define META_FILE_PARAMETER_PRESENT 0x01
121 #define META_VIRTUAL_DISK_SIZE_PRESENT 0x02
122 #define META_PAGE_83_PRESENT 0x04
123 #define META_LOGICAL_SECTOR_SIZE_PRESENT 0x08
124 #define META_PHYS_SECTOR_SIZE_PRESENT 0x10
125 #define META_PARENT_LOCATOR_PRESENT 0x20
126
127 #define META_ALL_PRESENT \
128 (META_FILE_PARAMETER_PRESENT | META_VIRTUAL_DISK_SIZE_PRESENT | \
129 META_PAGE_83_PRESENT | META_LOGICAL_SECTOR_SIZE_PRESENT | \
130 META_PHYS_SECTOR_SIZE_PRESENT)
131
132
133 typedef struct VHDXSectorInfo {
134 uint32_t bat_idx; /* BAT entry index */
135 uint32_t sectors_avail; /* sectors available in payload block */
136 uint32_t bytes_left; /* bytes left in the block after data to r/w */
137 uint32_t bytes_avail; /* bytes available in payload block */
138 uint64_t file_offset; /* absolute offset in bytes, in file */
139 uint64_t block_offset; /* block offset, in bytes */
140 } VHDXSectorInfo;
141
142 /* Calculates new checksum.
143 *
144 * Zero is substituted during crc calculation for the original crc field
145 * crc_offset: byte offset in buf of the buffer crc
146 * buf: buffer pointer
147 * size: size of buffer (must be > crc_offset+4)
148 *
149 * Note: The buffer should have all multi-byte data in little-endian format,
150 * and the resulting checksum is in little endian format.
151 */
vhdx_update_checksum(uint8_t * buf,size_t size,int crc_offset)152 uint32_t vhdx_update_checksum(uint8_t *buf, size_t size, int crc_offset)
153 {
154 uint32_t crc;
155
156 assert(buf != NULL);
157 assert(size > (crc_offset + sizeof(crc)));
158
159 memset(buf + crc_offset, 0, sizeof(crc));
160 crc = crc32c(0xffffffff, buf, size);
161 crc = cpu_to_le32(crc);
162 memcpy(buf + crc_offset, &crc, sizeof(crc));
163
164 return crc;
165 }
166
vhdx_checksum_calc(uint32_t crc,uint8_t * buf,size_t size,int crc_offset)167 uint32_t vhdx_checksum_calc(uint32_t crc, uint8_t *buf, size_t size,
168 int crc_offset)
169 {
170 uint32_t crc_new;
171 uint32_t crc_orig;
172 assert(buf != NULL);
173
174 if (crc_offset > 0) {
175 memcpy(&crc_orig, buf + crc_offset, sizeof(crc_orig));
176 memset(buf + crc_offset, 0, sizeof(crc_orig));
177 }
178
179 crc_new = crc32c(crc, buf, size);
180 if (crc_offset > 0) {
181 memcpy(buf + crc_offset, &crc_orig, sizeof(crc_orig));
182 }
183
184 return crc_new;
185 }
186
187 /* Validates the checksum of the buffer, with an in-place CRC.
188 *
189 * Zero is substituted during crc calculation for the original crc field,
190 * and the crc field is restored afterwards. But the buffer will be modified
191 * during the calculation, so this may not be not suitable for multi-threaded
192 * use.
193 *
194 * crc_offset: byte offset in buf of the buffer crc
195 * buf: buffer pointer
196 * size: size of buffer (must be > crc_offset+4)
197 *
198 * returns true if checksum is valid, false otherwise
199 */
vhdx_checksum_is_valid(uint8_t * buf,size_t size,int crc_offset)200 bool vhdx_checksum_is_valid(uint8_t *buf, size_t size, int crc_offset)
201 {
202 uint32_t crc_orig;
203 uint32_t crc;
204
205 assert(buf != NULL);
206 assert(size > (crc_offset + 4));
207
208 memcpy(&crc_orig, buf + crc_offset, sizeof(crc_orig));
209 crc_orig = le32_to_cpu(crc_orig);
210
211 crc = vhdx_checksum_calc(0xffffffff, buf, size, crc_offset);
212
213 return crc == crc_orig;
214 }
215
216
217 /*
218 * This generates a UUID that is compliant with the MS GUIDs used
219 * in the VHDX spec (and elsewhere).
220 */
vhdx_guid_generate(MSGUID * guid)221 void vhdx_guid_generate(MSGUID *guid)
222 {
223 QemuUUID uuid;
224 assert(guid != NULL);
225
226 qemu_uuid_generate(&uuid);
227 memcpy(guid, &uuid, sizeof(MSGUID));
228 }
229
230 /* Check for region overlaps inside the VHDX image */
vhdx_region_check(BDRVVHDXState * s,uint64_t start,uint64_t length)231 static int vhdx_region_check(BDRVVHDXState *s, uint64_t start, uint64_t length)
232 {
233 int ret = 0;
234 uint64_t end;
235 VHDXRegionEntry *r;
236
237 end = start + length;
238 QLIST_FOREACH(r, &s->regions, entries) {
239 if (!((start >= r->end) || (end <= r->start))) {
240 error_report("VHDX region %" PRIu64 "-%" PRIu64 " overlaps with "
241 "region %" PRIu64 "-%." PRIu64, start, end, r->start,
242 r->end);
243 ret = -EINVAL;
244 goto exit;
245 }
246 }
247
248 exit:
249 return ret;
250 }
251
252 /* Register a region for future checks */
vhdx_region_register(BDRVVHDXState * s,uint64_t start,uint64_t length)253 static void vhdx_region_register(BDRVVHDXState *s,
254 uint64_t start, uint64_t length)
255 {
256 VHDXRegionEntry *r;
257
258 r = g_malloc0(sizeof(*r));
259
260 r->start = start;
261 r->end = start + length;
262
263 QLIST_INSERT_HEAD(&s->regions, r, entries);
264 }
265
266 /* Free all registered regions */
vhdx_region_unregister_all(BDRVVHDXState * s)267 static void vhdx_region_unregister_all(BDRVVHDXState *s)
268 {
269 VHDXRegionEntry *r, *r_next;
270
271 QLIST_FOREACH_SAFE(r, &s->regions, entries, r_next) {
272 QLIST_REMOVE(r, entries);
273 g_free(r);
274 }
275 }
276
vhdx_set_shift_bits(BDRVVHDXState * s)277 static void vhdx_set_shift_bits(BDRVVHDXState *s)
278 {
279 s->logical_sector_size_bits = ctz32(s->logical_sector_size);
280 s->sectors_per_block_bits = ctz32(s->sectors_per_block);
281 s->chunk_ratio_bits = ctz64(s->chunk_ratio);
282 s->block_size_bits = ctz32(s->block_size);
283 }
284
285 /*
286 * Per the MS VHDX Specification, for every VHDX file:
287 * - The header section is fixed size - 1 MB
288 * - The header section is always the first "object"
289 * - The first 64KB of the header is the File Identifier
290 * - The first uint64 (8 bytes) is the VHDX Signature ("vhdxfile")
291 * - The following 512 bytes constitute a UTF-16 string identifiying the
292 * software that created the file, and is optional and diagnostic only.
293 *
294 * Therefore, we probe by looking for the vhdxfile signature "vhdxfile"
295 */
vhdx_probe(const uint8_t * buf,int buf_size,const char * filename)296 static int vhdx_probe(const uint8_t *buf, int buf_size, const char *filename)
297 {
298 if (buf_size >= 8 && !memcmp(buf, "vhdxfile", 8)) {
299 return 100;
300 }
301 return 0;
302 }
303
304 /*
305 * Writes the header to the specified offset.
306 *
307 * This will optionally read in buffer data from disk (otherwise zero-fill),
308 * and then update the header checksum. Header is converted to proper
309 * endianness before being written to the specified file offset
310 */
vhdx_write_header(BdrvChild * file,VHDXHeader * hdr,uint64_t offset,bool read)311 static int vhdx_write_header(BdrvChild *file, VHDXHeader *hdr,
312 uint64_t offset, bool read)
313 {
314 BlockDriverState *bs_file = file->bs;
315 uint8_t *buffer = NULL;
316 int ret;
317 VHDXHeader *header_le;
318
319 assert(bs_file != NULL);
320 assert(hdr != NULL);
321
322 /* the header checksum is not over just the packed size of VHDXHeader,
323 * but rather over the entire 'reserved' range for the header, which is
324 * 4KB (VHDX_HEADER_SIZE). */
325
326 buffer = qemu_blockalign(bs_file, VHDX_HEADER_SIZE);
327 if (read) {
328 /* if true, we can't assume the extra reserved bytes are 0 */
329 ret = bdrv_pread(file, offset, VHDX_HEADER_SIZE, buffer, 0);
330 if (ret < 0) {
331 goto exit;
332 }
333 } else {
334 memset(buffer, 0, VHDX_HEADER_SIZE);
335 }
336
337 /* overwrite the actual VHDXHeader portion */
338 header_le = (VHDXHeader *)buffer;
339 memcpy(header_le, hdr, sizeof(VHDXHeader));
340 vhdx_header_le_export(hdr, header_le);
341 vhdx_update_checksum(buffer, VHDX_HEADER_SIZE,
342 offsetof(VHDXHeader, checksum));
343 ret = bdrv_pwrite_sync(file, offset, sizeof(VHDXHeader), header_le, 0);
344
345 exit:
346 qemu_vfree(buffer);
347 return ret;
348 }
349
350 /* Update the VHDX headers
351 *
352 * This follows the VHDX spec procedures for header updates.
353 *
354 * - non-current header is updated with largest sequence number
355 */
356 static int GRAPH_RDLOCK
vhdx_update_header(BlockDriverState * bs,BDRVVHDXState * s,bool generate_data_write_guid,MSGUID * log_guid)357 vhdx_update_header(BlockDriverState *bs, BDRVVHDXState *s,
358 bool generate_data_write_guid, MSGUID *log_guid)
359 {
360 int ret = 0;
361 int hdr_idx = 0;
362 uint64_t header_offset = VHDX_HEADER1_OFFSET;
363
364 VHDXHeader *active_header;
365 VHDXHeader *inactive_header;
366
367 /* operate on the non-current header */
368 if (s->curr_header == 0) {
369 hdr_idx = 1;
370 header_offset = VHDX_HEADER2_OFFSET;
371 }
372
373 active_header = s->headers[s->curr_header];
374 inactive_header = s->headers[hdr_idx];
375
376 inactive_header->sequence_number = active_header->sequence_number + 1;
377
378 /* a new file guid must be generated before any file write, including
379 * headers */
380 inactive_header->file_write_guid = s->session_guid;
381
382 /* a new data guid only needs to be generated before any guest-visible
383 * writes (i.e. something observable via virtual disk read) */
384 if (generate_data_write_guid) {
385 vhdx_guid_generate(&inactive_header->data_write_guid);
386 }
387
388 /* update the log guid if present */
389 if (log_guid) {
390 inactive_header->log_guid = *log_guid;
391 }
392
393 ret = vhdx_write_header(bs->file, inactive_header, header_offset, true);
394 if (ret < 0) {
395 goto exit;
396 }
397 s->curr_header = hdr_idx;
398
399 exit:
400 return ret;
401 }
402
403 /*
404 * The VHDX spec calls for header updates to be performed twice, so that both
405 * the current and non-current header have valid info
406 */
vhdx_update_headers(BlockDriverState * bs,BDRVVHDXState * s,bool generate_data_write_guid,MSGUID * log_guid)407 int vhdx_update_headers(BlockDriverState *bs, BDRVVHDXState *s,
408 bool generate_data_write_guid, MSGUID *log_guid)
409 {
410 int ret;
411
412 ret = vhdx_update_header(bs, s, generate_data_write_guid, log_guid);
413 if (ret < 0) {
414 return ret;
415 }
416 return vhdx_update_header(bs, s, generate_data_write_guid, log_guid);
417 }
418
419 /* opens the specified header block from the VHDX file header section */
420 static void GRAPH_RDLOCK
vhdx_parse_header(BlockDriverState * bs,BDRVVHDXState * s,Error ** errp)421 vhdx_parse_header(BlockDriverState *bs, BDRVVHDXState *s, Error **errp)
422 {
423 int ret;
424 VHDXHeader *header1;
425 VHDXHeader *header2;
426 bool h1_valid = false;
427 bool h2_valid = false;
428 uint64_t h1_seq = 0;
429 uint64_t h2_seq = 0;
430 uint8_t *buffer;
431
432 /* header1 & header2 are freed in vhdx_close() */
433 header1 = qemu_blockalign(bs, sizeof(VHDXHeader));
434 header2 = qemu_blockalign(bs, sizeof(VHDXHeader));
435
436 buffer = qemu_blockalign(bs, VHDX_HEADER_SIZE);
437
438 s->headers[0] = header1;
439 s->headers[1] = header2;
440
441 /* We have to read the whole VHDX_HEADER_SIZE instead of
442 * sizeof(VHDXHeader), because the checksum is over the whole
443 * region */
444 ret = bdrv_pread(bs->file, VHDX_HEADER1_OFFSET, VHDX_HEADER_SIZE, buffer,
445 0);
446 if (ret < 0) {
447 goto fail;
448 }
449 /* copy over just the relevant portion that we need */
450 memcpy(header1, buffer, sizeof(VHDXHeader));
451
452 if (vhdx_checksum_is_valid(buffer, VHDX_HEADER_SIZE, 4)) {
453 vhdx_header_le_import(header1);
454 if (header1->signature == VHDX_HEADER_SIGNATURE &&
455 header1->version == 1) {
456 h1_seq = header1->sequence_number;
457 h1_valid = true;
458 }
459 }
460
461 ret = bdrv_pread(bs->file, VHDX_HEADER2_OFFSET, VHDX_HEADER_SIZE, buffer,
462 0);
463 if (ret < 0) {
464 goto fail;
465 }
466 /* copy over just the relevant portion that we need */
467 memcpy(header2, buffer, sizeof(VHDXHeader));
468
469 if (vhdx_checksum_is_valid(buffer, VHDX_HEADER_SIZE, 4)) {
470 vhdx_header_le_import(header2);
471 if (header2->signature == VHDX_HEADER_SIGNATURE &&
472 header2->version == 1) {
473 h2_seq = header2->sequence_number;
474 h2_valid = true;
475 }
476 }
477
478 /* If there is only 1 valid header (or no valid headers), we
479 * don't care what the sequence numbers are */
480 if (h1_valid && !h2_valid) {
481 s->curr_header = 0;
482 } else if (!h1_valid && h2_valid) {
483 s->curr_header = 1;
484 } else if (!h1_valid && !h2_valid) {
485 goto fail;
486 } else {
487 /* If both headers are valid, then we choose the active one by the
488 * highest sequence number. If the sequence numbers are equal, that is
489 * invalid */
490 if (h1_seq > h2_seq) {
491 s->curr_header = 0;
492 } else if (h2_seq > h1_seq) {
493 s->curr_header = 1;
494 } else {
495 /* The Microsoft Disk2VHD tool will create 2 identical
496 * headers, with identical sequence numbers. If the headers are
497 * identical, don't consider the file corrupt */
498 if (!memcmp(header1, header2, sizeof(VHDXHeader))) {
499 s->curr_header = 0;
500 } else {
501 goto fail;
502 }
503 }
504 }
505
506 vhdx_region_register(s, s->headers[s->curr_header]->log_offset,
507 s->headers[s->curr_header]->log_length);
508 goto exit;
509
510 fail:
511 error_setg_errno(errp, -ret, "No valid VHDX header found");
512 qemu_vfree(header1);
513 qemu_vfree(header2);
514 s->headers[0] = NULL;
515 s->headers[1] = NULL;
516 exit:
517 qemu_vfree(buffer);
518 }
519
520
521 static int GRAPH_RDLOCK
vhdx_open_region_tables(BlockDriverState * bs,BDRVVHDXState * s)522 vhdx_open_region_tables(BlockDriverState *bs, BDRVVHDXState *s)
523 {
524 int ret = 0;
525 uint8_t *buffer;
526 int offset = 0;
527 VHDXRegionTableEntry rt_entry;
528 uint32_t i;
529 bool bat_rt_found = false;
530 bool metadata_rt_found = false;
531
532 /* We have to read the whole 64KB block, because the crc32 is over the
533 * whole block */
534 buffer = qemu_blockalign(bs, VHDX_HEADER_BLOCK_SIZE);
535
536 ret = bdrv_pread(bs->file, VHDX_REGION_TABLE_OFFSET,
537 VHDX_HEADER_BLOCK_SIZE, buffer, 0);
538 if (ret < 0) {
539 goto fail;
540 }
541 memcpy(&s->rt, buffer, sizeof(s->rt));
542 offset += sizeof(s->rt);
543
544 if (!vhdx_checksum_is_valid(buffer, VHDX_HEADER_BLOCK_SIZE, 4)) {
545 ret = -EINVAL;
546 goto fail;
547 }
548
549 vhdx_region_header_le_import(&s->rt);
550
551 if (s->rt.signature != VHDX_REGION_SIGNATURE) {
552 ret = -EINVAL;
553 goto fail;
554 }
555
556
557 /* Per spec, maximum region table entry count is 2047 */
558 if (s->rt.entry_count > 2047) {
559 ret = -EINVAL;
560 goto fail;
561 }
562
563 for (i = 0; i < s->rt.entry_count; i++) {
564 memcpy(&rt_entry, buffer + offset, sizeof(rt_entry));
565 offset += sizeof(rt_entry);
566
567 vhdx_region_entry_le_import(&rt_entry);
568
569 /* check for region overlap between these entries, and any
570 * other memory regions in the file */
571 ret = vhdx_region_check(s, rt_entry.file_offset, rt_entry.length);
572 if (ret < 0) {
573 goto fail;
574 }
575
576 vhdx_region_register(s, rt_entry.file_offset, rt_entry.length);
577
578 /* see if we recognize the entry */
579 if (guid_eq(rt_entry.guid, bat_guid)) {
580 /* must be unique; if we have already found it this is invalid */
581 if (bat_rt_found) {
582 ret = -EINVAL;
583 goto fail;
584 }
585 bat_rt_found = true;
586 s->bat_rt = rt_entry;
587 continue;
588 }
589
590 if (guid_eq(rt_entry.guid, metadata_guid)) {
591 /* must be unique; if we have already found it this is invalid */
592 if (metadata_rt_found) {
593 ret = -EINVAL;
594 goto fail;
595 }
596 metadata_rt_found = true;
597 s->metadata_rt = rt_entry;
598 continue;
599 }
600
601 if (rt_entry.data_bits & VHDX_REGION_ENTRY_REQUIRED) {
602 /* cannot read vhdx file - required region table entry that
603 * we do not understand. per spec, we must fail to open */
604 ret = -ENOTSUP;
605 goto fail;
606 }
607 }
608
609 if (!bat_rt_found || !metadata_rt_found) {
610 ret = -EINVAL;
611 goto fail;
612 }
613
614 ret = 0;
615
616 fail:
617 qemu_vfree(buffer);
618 return ret;
619 }
620
621
622
623 /* Metadata initial parser
624 *
625 * This loads all the metadata entry fields. This may cause additional
626 * fields to be processed (e.g. parent locator, etc..).
627 *
628 * There are 5 Metadata items that are always required:
629 * - File Parameters (block size, has a parent)
630 * - Virtual Disk Size (size, in bytes, of the virtual drive)
631 * - Page 83 Data (scsi page 83 guid)
632 * - Logical Sector Size (logical sector size in bytes, either 512 or
633 * 4096. We only support 512 currently)
634 * - Physical Sector Size (512 or 4096)
635 *
636 * Also, if the File Parameters indicate this is a differencing file,
637 * we must also look for the Parent Locator metadata item.
638 */
639 static int GRAPH_RDLOCK
vhdx_parse_metadata(BlockDriverState * bs,BDRVVHDXState * s)640 vhdx_parse_metadata(BlockDriverState *bs, BDRVVHDXState *s)
641 {
642 int ret = 0;
643 uint8_t *buffer;
644 int offset = 0;
645 uint32_t i = 0;
646 VHDXMetadataTableEntry md_entry;
647
648 buffer = qemu_blockalign(bs, VHDX_METADATA_TABLE_MAX_SIZE);
649
650 ret = bdrv_pread(bs->file, s->metadata_rt.file_offset,
651 VHDX_METADATA_TABLE_MAX_SIZE, buffer, 0);
652 if (ret < 0) {
653 goto exit;
654 }
655 memcpy(&s->metadata_hdr, buffer, sizeof(s->metadata_hdr));
656 offset += sizeof(s->metadata_hdr);
657
658 vhdx_metadata_header_le_import(&s->metadata_hdr);
659
660 if (s->metadata_hdr.signature != VHDX_METADATA_SIGNATURE) {
661 ret = -EINVAL;
662 goto exit;
663 }
664
665 s->metadata_entries.present = 0;
666
667 if ((s->metadata_hdr.entry_count * sizeof(md_entry)) >
668 (VHDX_METADATA_TABLE_MAX_SIZE - offset)) {
669 ret = -EINVAL;
670 goto exit;
671 }
672
673 for (i = 0; i < s->metadata_hdr.entry_count; i++) {
674 memcpy(&md_entry, buffer + offset, sizeof(md_entry));
675 offset += sizeof(md_entry);
676
677 vhdx_metadata_entry_le_import(&md_entry);
678
679 if (guid_eq(md_entry.item_id, file_param_guid)) {
680 if (s->metadata_entries.present & META_FILE_PARAMETER_PRESENT) {
681 ret = -EINVAL;
682 goto exit;
683 }
684 s->metadata_entries.file_parameters_entry = md_entry;
685 s->metadata_entries.present |= META_FILE_PARAMETER_PRESENT;
686 continue;
687 }
688
689 if (guid_eq(md_entry.item_id, virtual_size_guid)) {
690 if (s->metadata_entries.present & META_VIRTUAL_DISK_SIZE_PRESENT) {
691 ret = -EINVAL;
692 goto exit;
693 }
694 s->metadata_entries.virtual_disk_size_entry = md_entry;
695 s->metadata_entries.present |= META_VIRTUAL_DISK_SIZE_PRESENT;
696 continue;
697 }
698
699 if (guid_eq(md_entry.item_id, page83_guid)) {
700 if (s->metadata_entries.present & META_PAGE_83_PRESENT) {
701 ret = -EINVAL;
702 goto exit;
703 }
704 s->metadata_entries.page83_data_entry = md_entry;
705 s->metadata_entries.present |= META_PAGE_83_PRESENT;
706 continue;
707 }
708
709 if (guid_eq(md_entry.item_id, logical_sector_guid)) {
710 if (s->metadata_entries.present &
711 META_LOGICAL_SECTOR_SIZE_PRESENT) {
712 ret = -EINVAL;
713 goto exit;
714 }
715 s->metadata_entries.logical_sector_size_entry = md_entry;
716 s->metadata_entries.present |= META_LOGICAL_SECTOR_SIZE_PRESENT;
717 continue;
718 }
719
720 if (guid_eq(md_entry.item_id, phys_sector_guid)) {
721 if (s->metadata_entries.present & META_PHYS_SECTOR_SIZE_PRESENT) {
722 ret = -EINVAL;
723 goto exit;
724 }
725 s->metadata_entries.phys_sector_size_entry = md_entry;
726 s->metadata_entries.present |= META_PHYS_SECTOR_SIZE_PRESENT;
727 continue;
728 }
729
730 if (guid_eq(md_entry.item_id, parent_locator_guid)) {
731 if (s->metadata_entries.present & META_PARENT_LOCATOR_PRESENT) {
732 ret = -EINVAL;
733 goto exit;
734 }
735 s->metadata_entries.parent_locator_entry = md_entry;
736 s->metadata_entries.present |= META_PARENT_LOCATOR_PRESENT;
737 continue;
738 }
739
740 if (md_entry.data_bits & VHDX_META_FLAGS_IS_REQUIRED) {
741 /* cannot read vhdx file - required region table entry that
742 * we do not understand. per spec, we must fail to open */
743 ret = -ENOTSUP;
744 goto exit;
745 }
746 }
747
748 if (s->metadata_entries.present != META_ALL_PRESENT) {
749 ret = -ENOTSUP;
750 goto exit;
751 }
752
753 ret = bdrv_pread(bs->file,
754 s->metadata_entries.file_parameters_entry.offset
755 + s->metadata_rt.file_offset,
756 sizeof(s->params),
757 &s->params,
758 0);
759
760 if (ret < 0) {
761 goto exit;
762 }
763
764 s->params.block_size = le32_to_cpu(s->params.block_size);
765 s->params.data_bits = le32_to_cpu(s->params.data_bits);
766
767
768 /* We now have the file parameters, so we can tell if this is a
769 * differencing file (i.e.. has_parent), is dynamic or fixed
770 * sized (leave_blocks_allocated), and the block size */
771
772 /* The parent locator required iff the file parameters has_parent set */
773 if (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) {
774 if (s->metadata_entries.present & META_PARENT_LOCATOR_PRESENT) {
775 /* TODO: parse parent locator fields */
776 ret = -ENOTSUP; /* temp, until differencing files are supported */
777 goto exit;
778 } else {
779 /* if has_parent is set, but there is not parent locator present,
780 * then that is an invalid combination */
781 ret = -EINVAL;
782 goto exit;
783 }
784 }
785
786 /* determine virtual disk size, logical sector size,
787 * and phys sector size */
788
789 ret = bdrv_pread(bs->file,
790 s->metadata_entries.virtual_disk_size_entry.offset
791 + s->metadata_rt.file_offset,
792 sizeof(uint64_t),
793 &s->virtual_disk_size,
794 0);
795 if (ret < 0) {
796 goto exit;
797 }
798 ret = bdrv_pread(bs->file,
799 s->metadata_entries.logical_sector_size_entry.offset
800 + s->metadata_rt.file_offset,
801 sizeof(uint32_t),
802 &s->logical_sector_size,
803 0);
804 if (ret < 0) {
805 goto exit;
806 }
807 ret = bdrv_pread(bs->file,
808 s->metadata_entries.phys_sector_size_entry.offset
809 + s->metadata_rt.file_offset,
810 sizeof(uint32_t),
811 &s->physical_sector_size,
812 0);
813 if (ret < 0) {
814 goto exit;
815 }
816
817 s->virtual_disk_size = le64_to_cpu(s->virtual_disk_size);
818 s->logical_sector_size = le32_to_cpu(s->logical_sector_size);
819 s->physical_sector_size = le32_to_cpu(s->physical_sector_size);
820
821 if (s->params.block_size < VHDX_BLOCK_SIZE_MIN ||
822 s->params.block_size > VHDX_BLOCK_SIZE_MAX) {
823 ret = -EINVAL;
824 goto exit;
825 }
826
827 /* Currently we only support 512 */
828 if (s->logical_sector_size != 512) {
829 ret = -ENOTSUP;
830 goto exit;
831 }
832
833 /* Both block_size and sector_size are guaranteed powers of 2, below.
834 Due to range checks above, s->sectors_per_block can never be < 256 */
835 s->sectors_per_block = s->params.block_size / s->logical_sector_size;
836 s->chunk_ratio = (VHDX_MAX_SECTORS_PER_BLOCK) *
837 (uint64_t)s->logical_sector_size /
838 (uint64_t)s->params.block_size;
839
840 /* These values are ones we will want to use for division / multiplication
841 * later on, and they are all guaranteed (per the spec) to be powers of 2,
842 * so we can take advantage of that for shift operations during
843 * reads/writes */
844 if (s->logical_sector_size & (s->logical_sector_size - 1)) {
845 ret = -EINVAL;
846 goto exit;
847 }
848 if (s->sectors_per_block & (s->sectors_per_block - 1)) {
849 ret = -EINVAL;
850 goto exit;
851 }
852 if (s->chunk_ratio & (s->chunk_ratio - 1)) {
853 ret = -EINVAL;
854 goto exit;
855 }
856 s->block_size = s->params.block_size;
857 if (s->block_size & (s->block_size - 1)) {
858 ret = -EINVAL;
859 goto exit;
860 }
861
862 vhdx_set_shift_bits(s);
863
864 ret = 0;
865
866 exit:
867 qemu_vfree(buffer);
868 return ret;
869 }
870
871 /*
872 * Calculate the number of BAT entries, including sector
873 * bitmap entries.
874 */
vhdx_calc_bat_entries(BDRVVHDXState * s)875 static void vhdx_calc_bat_entries(BDRVVHDXState *s)
876 {
877 uint32_t data_blocks_cnt, bitmap_blocks_cnt;
878
879 data_blocks_cnt = DIV_ROUND_UP(s->virtual_disk_size, s->block_size);
880 bitmap_blocks_cnt = DIV_ROUND_UP(data_blocks_cnt, s->chunk_ratio);
881
882 if (s->parent_entries) {
883 s->bat_entries = bitmap_blocks_cnt * (s->chunk_ratio + 1);
884 } else {
885 s->bat_entries = data_blocks_cnt +
886 ((data_blocks_cnt - 1) >> s->chunk_ratio_bits);
887 }
888
889 }
890
891 static int coroutine_mixed_fn GRAPH_RDLOCK
vhdx_check_bat_entries(BlockDriverState * bs,int * errcnt)892 vhdx_check_bat_entries(BlockDriverState *bs, int *errcnt)
893 {
894 BDRVVHDXState *s = bs->opaque;
895 int64_t image_file_size = bdrv_getlength(bs->file->bs);
896 uint64_t payblocks = s->chunk_ratio;
897 uint64_t i;
898 int ret = 0;
899
900 if (image_file_size < 0) {
901 error_report("Could not determinate VHDX image file size.");
902 return image_file_size;
903 }
904
905 for (i = 0; i < s->bat_entries; i++) {
906 if ((s->bat[i] & VHDX_BAT_STATE_BIT_MASK) ==
907 PAYLOAD_BLOCK_FULLY_PRESENT) {
908 uint64_t offset = s->bat[i] & VHDX_BAT_FILE_OFF_MASK;
909 /*
910 * Allow that the last block exists only partially. The VHDX spec
911 * states that the image file can only grow in blocksize increments,
912 * but QEMU created images with partial last blocks in the past.
913 */
914 uint32_t block_length = MIN(s->block_size,
915 bs->total_sectors * BDRV_SECTOR_SIZE - i * s->block_size);
916 /*
917 * Check for BAT entry overflow.
918 */
919 if (offset > INT64_MAX - s->block_size) {
920 error_report("VHDX BAT entry %" PRIu64 " offset overflow.", i);
921 ret = -EINVAL;
922 if (!errcnt) {
923 break;
924 }
925 (*errcnt)++;
926 }
927 /*
928 * Check if fully allocated BAT entries do not reside after
929 * end of the image file.
930 */
931 if (offset >= image_file_size) {
932 error_report("VHDX BAT entry %" PRIu64 " start offset %" PRIu64
933 " points after end of file (%" PRIi64 "). Image"
934 " has probably been truncated.",
935 i, offset, image_file_size);
936 ret = -EINVAL;
937 if (!errcnt) {
938 break;
939 }
940 (*errcnt)++;
941 } else if (offset + block_length > image_file_size) {
942 error_report("VHDX BAT entry %" PRIu64 " end offset %" PRIu64
943 " points after end of file (%" PRIi64 "). Image"
944 " has probably been truncated.",
945 i, offset + block_length - 1, image_file_size);
946 ret = -EINVAL;
947 if (!errcnt) {
948 break;
949 }
950 (*errcnt)++;
951 }
952
953 /*
954 * verify populated BAT field file offsets against
955 * region table and log entries
956 */
957 if (payblocks--) {
958 /* payload bat entries */
959 int ret2;
960 ret2 = vhdx_region_check(s, offset, s->block_size);
961 if (ret2 < 0) {
962 ret = -EINVAL;
963 if (!errcnt) {
964 break;
965 }
966 (*errcnt)++;
967 }
968 } else {
969 payblocks = s->chunk_ratio;
970 /*
971 * Once differencing files are supported, verify sector bitmap
972 * blocks here
973 */
974 }
975 }
976 }
977
978 return ret;
979 }
980
vhdx_close(BlockDriverState * bs)981 static void vhdx_close(BlockDriverState *bs)
982 {
983 BDRVVHDXState *s = bs->opaque;
984 qemu_vfree(s->headers[0]);
985 s->headers[0] = NULL;
986 qemu_vfree(s->headers[1]);
987 s->headers[1] = NULL;
988 qemu_vfree(s->bat);
989 s->bat = NULL;
990 qemu_vfree(s->parent_entries);
991 s->parent_entries = NULL;
992 migrate_del_blocker(&s->migration_blocker);
993 qemu_vfree(s->log.hdr);
994 s->log.hdr = NULL;
995 vhdx_region_unregister_all(s);
996 }
997
vhdx_open(BlockDriverState * bs,QDict * options,int flags,Error ** errp)998 static int vhdx_open(BlockDriverState *bs, QDict *options, int flags,
999 Error **errp)
1000 {
1001 BDRVVHDXState *s = bs->opaque;
1002 int ret = 0;
1003 uint32_t i;
1004 uint64_t signature;
1005 Error *local_err = NULL;
1006
1007 GLOBAL_STATE_CODE();
1008
1009 ret = bdrv_open_file_child(NULL, options, "file", bs, errp);
1010 if (ret < 0) {
1011 return ret;
1012 }
1013
1014 GRAPH_RDLOCK_GUARD_MAINLOOP();
1015
1016 s->bat = NULL;
1017 s->first_visible_write = true;
1018
1019 qemu_co_mutex_init(&s->lock);
1020 QLIST_INIT(&s->regions);
1021
1022 /* validate the file signature */
1023 ret = bdrv_pread(bs->file, 0, sizeof(uint64_t), &signature, 0);
1024 if (ret < 0) {
1025 goto fail;
1026 }
1027 if (memcmp(&signature, "vhdxfile", 8)) {
1028 ret = -EINVAL;
1029 goto fail;
1030 }
1031
1032 /* This is used for any header updates, for the file_write_guid.
1033 * The spec dictates that a new value should be used for the first
1034 * header update */
1035 vhdx_guid_generate(&s->session_guid);
1036
1037 vhdx_parse_header(bs, s, &local_err);
1038 if (local_err != NULL) {
1039 error_propagate(errp, local_err);
1040 ret = -EINVAL;
1041 goto fail;
1042 }
1043
1044 ret = vhdx_parse_log(bs, s, &s->log_replayed_on_open, errp);
1045 if (ret < 0) {
1046 goto fail;
1047 }
1048
1049 ret = vhdx_open_region_tables(bs, s);
1050 if (ret < 0) {
1051 goto fail;
1052 }
1053
1054 ret = vhdx_parse_metadata(bs, s);
1055 if (ret < 0) {
1056 goto fail;
1057 }
1058
1059 s->block_size = s->params.block_size;
1060
1061 /* the VHDX spec dictates that virtual_disk_size is always a multiple of
1062 * logical_sector_size */
1063 bs->total_sectors = s->virtual_disk_size >> s->logical_sector_size_bits;
1064
1065 vhdx_calc_bat_entries(s);
1066
1067 s->bat_offset = s->bat_rt.file_offset;
1068
1069 if (s->bat_entries > s->bat_rt.length / sizeof(VHDXBatEntry)) {
1070 /* BAT allocation is not large enough for all entries */
1071 ret = -EINVAL;
1072 goto fail;
1073 }
1074
1075 /* s->bat is freed in vhdx_close() */
1076 s->bat = qemu_try_blockalign(bs->file->bs, s->bat_rt.length);
1077 if (s->bat == NULL) {
1078 ret = -ENOMEM;
1079 goto fail;
1080 }
1081
1082 ret = bdrv_pread(bs->file, s->bat_offset, s->bat_rt.length, s->bat, 0);
1083 if (ret < 0) {
1084 goto fail;
1085 }
1086
1087 /* endian convert populated BAT field entries */
1088 for (i = 0; i < s->bat_entries; i++) {
1089 s->bat[i] = le64_to_cpu(s->bat[i]);
1090 }
1091
1092 if (!(flags & BDRV_O_CHECK)) {
1093 ret = vhdx_check_bat_entries(bs, NULL);
1094 if (ret < 0) {
1095 goto fail;
1096 }
1097 }
1098
1099 /* Disable migration when VHDX images are used */
1100 error_setg(&s->migration_blocker, "The vhdx format used by node '%s' "
1101 "does not support live migration",
1102 bdrv_get_device_or_node_name(bs));
1103 ret = migrate_add_blocker_normal(&s->migration_blocker, errp);
1104 if (ret < 0) {
1105 goto fail;
1106 }
1107
1108 /* TODO: differencing files */
1109
1110 return 0;
1111 fail:
1112 vhdx_close(bs);
1113 return ret;
1114 }
1115
vhdx_reopen_prepare(BDRVReopenState * state,BlockReopenQueue * queue,Error ** errp)1116 static int vhdx_reopen_prepare(BDRVReopenState *state,
1117 BlockReopenQueue *queue, Error **errp)
1118 {
1119 return 0;
1120 }
1121
1122
1123 /*
1124 * Perform sector to block offset translations, to get various
1125 * sector and file offsets into the image. See VHDXSectorInfo
1126 */
vhdx_block_translate(BDRVVHDXState * s,int64_t sector_num,int nb_sectors,VHDXSectorInfo * sinfo)1127 static void vhdx_block_translate(BDRVVHDXState *s, int64_t sector_num,
1128 int nb_sectors, VHDXSectorInfo *sinfo)
1129 {
1130 uint32_t block_offset;
1131
1132 sinfo->bat_idx = sector_num >> s->sectors_per_block_bits;
1133 /* effectively a modulo - this gives us the offset into the block
1134 * (in sector sizes) for our sector number */
1135 block_offset = sector_num - (sinfo->bat_idx << s->sectors_per_block_bits);
1136 /* the chunk ratio gives us the interleaving of the sector
1137 * bitmaps, so we need to advance our page block index by the
1138 * sector bitmaps entry number */
1139 sinfo->bat_idx += sinfo->bat_idx >> s->chunk_ratio_bits;
1140
1141 /* the number of sectors we can read/write in this cycle */
1142 sinfo->sectors_avail = s->sectors_per_block - block_offset;
1143
1144 sinfo->bytes_left = sinfo->sectors_avail << s->logical_sector_size_bits;
1145
1146 if (sinfo->sectors_avail > nb_sectors) {
1147 sinfo->sectors_avail = nb_sectors;
1148 }
1149
1150 sinfo->bytes_avail = sinfo->sectors_avail << s->logical_sector_size_bits;
1151
1152 sinfo->file_offset = s->bat[sinfo->bat_idx] & VHDX_BAT_FILE_OFF_MASK;
1153
1154 sinfo->block_offset = block_offset << s->logical_sector_size_bits;
1155
1156 /* The file offset must be past the header section, so must be > 0 */
1157 if (sinfo->file_offset == 0) {
1158 return;
1159 }
1160
1161 /* block offset is the offset in vhdx logical sectors, in
1162 * the payload data block. Convert that to a byte offset
1163 * in the block, and add in the payload data block offset
1164 * in the file, in bytes, to get the final read address */
1165
1166 sinfo->file_offset += sinfo->block_offset;
1167 }
1168
1169
1170 static int coroutine_fn
vhdx_co_get_info(BlockDriverState * bs,BlockDriverInfo * bdi)1171 vhdx_co_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
1172 {
1173 BDRVVHDXState *s = bs->opaque;
1174
1175 bdi->cluster_size = s->block_size;
1176
1177 return 0;
1178 }
1179
1180
1181 static int coroutine_fn GRAPH_RDLOCK
vhdx_co_readv(BlockDriverState * bs,int64_t sector_num,int nb_sectors,QEMUIOVector * qiov)1182 vhdx_co_readv(BlockDriverState *bs, int64_t sector_num, int nb_sectors,
1183 QEMUIOVector *qiov)
1184 {
1185 BDRVVHDXState *s = bs->opaque;
1186 int ret = 0;
1187 VHDXSectorInfo sinfo;
1188 uint64_t bytes_done = 0;
1189 QEMUIOVector hd_qiov;
1190
1191 qemu_iovec_init(&hd_qiov, qiov->niov);
1192
1193 qemu_co_mutex_lock(&s->lock);
1194
1195 while (nb_sectors > 0) {
1196 /* We are a differencing file, so we need to inspect the sector bitmap
1197 * to see if we have the data or not */
1198 if (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) {
1199 /* not supported yet */
1200 ret = -ENOTSUP;
1201 goto exit;
1202 } else {
1203 vhdx_block_translate(s, sector_num, nb_sectors, &sinfo);
1204
1205 qemu_iovec_reset(&hd_qiov);
1206 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, sinfo.bytes_avail);
1207
1208 /* check the payload block state */
1209 switch (s->bat[sinfo.bat_idx] & VHDX_BAT_STATE_BIT_MASK) {
1210 case PAYLOAD_BLOCK_NOT_PRESENT: /* fall through */
1211 case PAYLOAD_BLOCK_UNDEFINED:
1212 case PAYLOAD_BLOCK_UNMAPPED:
1213 case PAYLOAD_BLOCK_UNMAPPED_v095:
1214 case PAYLOAD_BLOCK_ZERO:
1215 /* return zero */
1216 qemu_iovec_memset(&hd_qiov, 0, 0, sinfo.bytes_avail);
1217 break;
1218 case PAYLOAD_BLOCK_FULLY_PRESENT:
1219 qemu_co_mutex_unlock(&s->lock);
1220 ret = bdrv_co_preadv(bs->file, sinfo.file_offset,
1221 sinfo.sectors_avail * BDRV_SECTOR_SIZE,
1222 &hd_qiov, 0);
1223 qemu_co_mutex_lock(&s->lock);
1224 if (ret < 0) {
1225 goto exit;
1226 }
1227 break;
1228 case PAYLOAD_BLOCK_PARTIALLY_PRESENT:
1229 /* we don't yet support difference files, fall through
1230 * to error */
1231 default:
1232 ret = -EIO;
1233 goto exit;
1234 break;
1235 }
1236 nb_sectors -= sinfo.sectors_avail;
1237 sector_num += sinfo.sectors_avail;
1238 bytes_done += sinfo.bytes_avail;
1239 }
1240 }
1241 ret = 0;
1242 exit:
1243 qemu_co_mutex_unlock(&s->lock);
1244 qemu_iovec_destroy(&hd_qiov);
1245 return ret;
1246 }
1247
1248 /*
1249 * Allocate a new payload block at the end of the file.
1250 *
1251 * Allocation will happen at 1MB alignment inside the file.
1252 *
1253 * If @need_zero is set on entry but not cleared on return, then truncation
1254 * could not guarantee that the new portion reads as zero, and the caller
1255 * will take care of it instead.
1256 *
1257 * Returns the file offset start of the new payload block
1258 */
1259 static int coroutine_fn GRAPH_RDLOCK
vhdx_allocate_block(BlockDriverState * bs,BDRVVHDXState * s,uint64_t * new_offset,bool * need_zero)1260 vhdx_allocate_block(BlockDriverState *bs, BDRVVHDXState *s,
1261 uint64_t *new_offset, bool *need_zero)
1262 {
1263 int64_t current_len;
1264
1265 current_len = bdrv_co_getlength(bs->file->bs);
1266 if (current_len < 0) {
1267 return current_len;
1268 }
1269
1270 *new_offset = current_len;
1271
1272 /* per the spec, the address for a block is in units of 1MB */
1273 *new_offset = ROUND_UP(*new_offset, 1 * MiB);
1274 if (*new_offset > INT64_MAX) {
1275 return -EINVAL;
1276 }
1277
1278 if (*need_zero) {
1279 int ret;
1280
1281 ret = bdrv_co_truncate(bs->file, *new_offset + s->block_size, false,
1282 PREALLOC_MODE_OFF, BDRV_REQ_ZERO_WRITE, NULL);
1283 if (ret != -ENOTSUP) {
1284 *need_zero = false;
1285 return ret;
1286 }
1287 }
1288
1289 return bdrv_co_truncate(bs->file, *new_offset + s->block_size, false,
1290 PREALLOC_MODE_OFF, 0, NULL);
1291 }
1292
1293 /*
1294 * Update the BAT table entry with the new file offset, and the new entry
1295 * state */
vhdx_update_bat_table_entry(BlockDriverState * bs,BDRVVHDXState * s,VHDXSectorInfo * sinfo,uint64_t * bat_entry_le,uint64_t * bat_offset,int state)1296 static void vhdx_update_bat_table_entry(BlockDriverState *bs, BDRVVHDXState *s,
1297 VHDXSectorInfo *sinfo,
1298 uint64_t *bat_entry_le,
1299 uint64_t *bat_offset, int state)
1300 {
1301 /* The BAT entry is a uint64, with 44 bits for the file offset in units of
1302 * 1MB, and 3 bits for the block state. */
1303 if ((state == PAYLOAD_BLOCK_ZERO) ||
1304 (state == PAYLOAD_BLOCK_UNDEFINED) ||
1305 (state == PAYLOAD_BLOCK_NOT_PRESENT) ||
1306 (state == PAYLOAD_BLOCK_UNMAPPED)) {
1307 s->bat[sinfo->bat_idx] = 0; /* For PAYLOAD_BLOCK_ZERO, the
1308 FileOffsetMB field is denoted as
1309 'reserved' in the v1.0 spec. If it is
1310 non-zero, MS Hyper-V will fail to read
1311 the disk image */
1312 } else {
1313 s->bat[sinfo->bat_idx] = sinfo->file_offset;
1314 }
1315
1316 s->bat[sinfo->bat_idx] |= state & VHDX_BAT_STATE_BIT_MASK;
1317
1318 *bat_entry_le = cpu_to_le64(s->bat[sinfo->bat_idx]);
1319 *bat_offset = s->bat_offset + sinfo->bat_idx * sizeof(VHDXBatEntry);
1320
1321 }
1322
1323 /* Per the spec, on the first write of guest-visible data to the file the
1324 * data write guid must be updated in the header */
vhdx_user_visible_write(BlockDriverState * bs,BDRVVHDXState * s)1325 int vhdx_user_visible_write(BlockDriverState *bs, BDRVVHDXState *s)
1326 {
1327 int ret = 0;
1328 if (s->first_visible_write) {
1329 s->first_visible_write = false;
1330 ret = vhdx_update_headers(bs, s, true, NULL);
1331 }
1332 return ret;
1333 }
1334
1335 static int coroutine_fn GRAPH_RDLOCK
vhdx_co_writev(BlockDriverState * bs,int64_t sector_num,int nb_sectors,QEMUIOVector * qiov,int flags)1336 vhdx_co_writev(BlockDriverState *bs, int64_t sector_num, int nb_sectors,
1337 QEMUIOVector *qiov, int flags)
1338 {
1339 int ret = -ENOTSUP;
1340 BDRVVHDXState *s = bs->opaque;
1341 VHDXSectorInfo sinfo;
1342 uint64_t bytes_done = 0;
1343 uint64_t bat_entry = 0;
1344 uint64_t bat_entry_offset = 0;
1345 QEMUIOVector hd_qiov;
1346 struct iovec iov1 = { 0 };
1347 struct iovec iov2 = { 0 };
1348 int sectors_to_write;
1349 int bat_state;
1350 uint64_t bat_prior_offset = 0;
1351 bool bat_update = false;
1352
1353 qemu_iovec_init(&hd_qiov, qiov->niov);
1354
1355 qemu_co_mutex_lock(&s->lock);
1356
1357 ret = vhdx_user_visible_write(bs, s);
1358 if (ret < 0) {
1359 goto exit;
1360 }
1361
1362 while (nb_sectors > 0) {
1363 bool use_zero_buffers = false;
1364 bat_update = false;
1365 if (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) {
1366 /* not supported yet */
1367 ret = -ENOTSUP;
1368 goto exit;
1369 } else {
1370 vhdx_block_translate(s, sector_num, nb_sectors, &sinfo);
1371 sectors_to_write = sinfo.sectors_avail;
1372
1373 qemu_iovec_reset(&hd_qiov);
1374 /* check the payload block state */
1375 bat_state = s->bat[sinfo.bat_idx] & VHDX_BAT_STATE_BIT_MASK;
1376 switch (bat_state) {
1377 case PAYLOAD_BLOCK_ZERO:
1378 /* in this case, we need to preserve zero writes for
1379 * data that is not part of this write, so we must pad
1380 * the rest of the buffer to zeroes */
1381 use_zero_buffers = true;
1382 /* fall through */
1383 case PAYLOAD_BLOCK_NOT_PRESENT: /* fall through */
1384 case PAYLOAD_BLOCK_UNMAPPED:
1385 case PAYLOAD_BLOCK_UNMAPPED_v095:
1386 case PAYLOAD_BLOCK_UNDEFINED:
1387 bat_prior_offset = sinfo.file_offset;
1388 ret = vhdx_allocate_block(bs, s, &sinfo.file_offset,
1389 &use_zero_buffers);
1390 if (ret < 0) {
1391 goto exit;
1392 }
1393 /*
1394 * once we support differencing files, this may also be
1395 * partially present
1396 */
1397 /* update block state to the newly specified state */
1398 vhdx_update_bat_table_entry(bs, s, &sinfo, &bat_entry,
1399 &bat_entry_offset,
1400 PAYLOAD_BLOCK_FULLY_PRESENT);
1401 bat_update = true;
1402 /*
1403 * Since we just allocated a block, file_offset is the
1404 * beginning of the payload block. It needs to be the
1405 * write address, which includes the offset into the
1406 * block, unless the entire block needs to read as
1407 * zeroes but truncation was not able to provide them,
1408 * in which case we need to fill in the rest.
1409 */
1410 if (!use_zero_buffers) {
1411 sinfo.file_offset += sinfo.block_offset;
1412 } else {
1413 /* zero fill the front, if any */
1414 if (sinfo.block_offset) {
1415 iov1.iov_len = sinfo.block_offset;
1416 iov1.iov_base = qemu_blockalign(bs, iov1.iov_len);
1417 memset(iov1.iov_base, 0, iov1.iov_len);
1418 qemu_iovec_concat_iov(&hd_qiov, &iov1, 1, 0,
1419 iov1.iov_len);
1420 sectors_to_write += iov1.iov_len >> BDRV_SECTOR_BITS;
1421 }
1422
1423 /* our actual data */
1424 qemu_iovec_concat(&hd_qiov, qiov, bytes_done,
1425 sinfo.bytes_avail);
1426
1427 /* zero fill the back, if any */
1428 if ((sinfo.bytes_avail - sinfo.block_offset) <
1429 s->block_size) {
1430 iov2.iov_len = s->block_size -
1431 (sinfo.bytes_avail + sinfo.block_offset);
1432 iov2.iov_base = qemu_blockalign(bs, iov2.iov_len);
1433 memset(iov2.iov_base, 0, iov2.iov_len);
1434 qemu_iovec_concat_iov(&hd_qiov, &iov2, 1, 0,
1435 iov2.iov_len);
1436 sectors_to_write += iov2.iov_len >> BDRV_SECTOR_BITS;
1437 }
1438 }
1439
1440 /* fall through */
1441 case PAYLOAD_BLOCK_FULLY_PRESENT:
1442 /* if the file offset address is in the header zone,
1443 * there is a problem */
1444 if (sinfo.file_offset < (1 * MiB)) {
1445 ret = -EFAULT;
1446 goto error_bat_restore;
1447 }
1448
1449 if (!use_zero_buffers) {
1450 qemu_iovec_concat(&hd_qiov, qiov, bytes_done,
1451 sinfo.bytes_avail);
1452 }
1453 /* block exists, so we can just overwrite it */
1454 qemu_co_mutex_unlock(&s->lock);
1455 ret = bdrv_co_pwritev(bs->file, sinfo.file_offset,
1456 sectors_to_write * BDRV_SECTOR_SIZE,
1457 &hd_qiov, 0);
1458 qemu_co_mutex_lock(&s->lock);
1459 if (ret < 0) {
1460 goto error_bat_restore;
1461 }
1462 break;
1463 case PAYLOAD_BLOCK_PARTIALLY_PRESENT:
1464 /* we don't yet support difference files, fall through
1465 * to error */
1466 default:
1467 ret = -EIO;
1468 goto exit;
1469 break;
1470 }
1471
1472 if (bat_update) {
1473 /* this will update the BAT entry into the log journal, and
1474 * then flush the log journal out to disk */
1475 ret = vhdx_log_write_and_flush(bs, s, &bat_entry,
1476 sizeof(VHDXBatEntry),
1477 bat_entry_offset);
1478 if (ret < 0) {
1479 goto exit;
1480 }
1481 }
1482
1483 nb_sectors -= sinfo.sectors_avail;
1484 sector_num += sinfo.sectors_avail;
1485 bytes_done += sinfo.bytes_avail;
1486
1487 }
1488 }
1489
1490 goto exit;
1491
1492 error_bat_restore:
1493 if (bat_update) {
1494 /* keep metadata in sync, and restore the bat entry state
1495 * if error. */
1496 sinfo.file_offset = bat_prior_offset;
1497 vhdx_update_bat_table_entry(bs, s, &sinfo, &bat_entry,
1498 &bat_entry_offset, bat_state);
1499 }
1500 exit:
1501 qemu_vfree(iov1.iov_base);
1502 qemu_vfree(iov2.iov_base);
1503 qemu_co_mutex_unlock(&s->lock);
1504 qemu_iovec_destroy(&hd_qiov);
1505 return ret;
1506 }
1507
1508
1509
1510 /*
1511 * Create VHDX Headers
1512 *
1513 * There are 2 headers, and the highest sequence number will represent
1514 * the active header
1515 */
1516 static int coroutine_fn GRAPH_UNLOCKED
vhdx_create_new_headers(BlockBackend * blk,uint64_t image_size,uint32_t log_size)1517 vhdx_create_new_headers(BlockBackend *blk, uint64_t image_size,
1518 uint32_t log_size)
1519 {
1520 BlockDriverState *bs = blk_bs(blk);
1521 BdrvChild *child;
1522 int ret = 0;
1523 VHDXHeader *hdr = NULL;
1524
1525 GRAPH_RDLOCK_GUARD();
1526
1527 hdr = g_new0(VHDXHeader, 1);
1528
1529 hdr->signature = VHDX_HEADER_SIGNATURE;
1530 hdr->sequence_number = g_random_int();
1531 hdr->log_version = 0;
1532 hdr->version = 1;
1533 hdr->log_length = log_size;
1534 hdr->log_offset = VHDX_HEADER_SECTION_END;
1535 vhdx_guid_generate(&hdr->file_write_guid);
1536 vhdx_guid_generate(&hdr->data_write_guid);
1537
1538 /* XXX Ugly way to get blk->root, but that's a feature, not a bug. This
1539 * hack makes it obvious that vhdx_write_header() bypasses the BlockBackend
1540 * here, which it really shouldn't be doing. */
1541 child = QLIST_FIRST(&bs->parents);
1542 assert(!QLIST_NEXT(child, next_parent));
1543
1544 ret = vhdx_write_header(child, hdr, VHDX_HEADER1_OFFSET, false);
1545 if (ret < 0) {
1546 goto exit;
1547 }
1548 hdr->sequence_number++;
1549 ret = vhdx_write_header(child, hdr, VHDX_HEADER2_OFFSET, false);
1550 if (ret < 0) {
1551 goto exit;
1552 }
1553
1554 exit:
1555 g_free(hdr);
1556 return ret;
1557 }
1558
1559 #define VHDX_METADATA_ENTRY_BUFFER_SIZE \
1560 (sizeof(VHDXFileParameters) +\
1561 sizeof(VHDXVirtualDiskSize) +\
1562 sizeof(VHDXPage83Data) +\
1563 sizeof(VHDXVirtualDiskLogicalSectorSize) +\
1564 sizeof(VHDXVirtualDiskPhysicalSectorSize))
1565
1566 /*
1567 * Create the Metadata entries.
1568 *
1569 * For more details on the entries, see section 3.5 (pg 29) in the
1570 * VHDX 1.00 specification.
1571 *
1572 * We support 5 metadata entries (all required by spec):
1573 * File Parameters,
1574 * Virtual Disk Size,
1575 * Page 83 Data,
1576 * Logical Sector Size,
1577 * Physical Sector Size
1578 *
1579 * The first 64KB of the Metadata section is reserved for the metadata
1580 * header and entries; beyond that, the metadata items themselves reside.
1581 */
1582 static int coroutine_fn
vhdx_create_new_metadata(BlockBackend * blk,uint64_t image_size,uint32_t block_size,uint32_t sector_size,uint64_t metadata_offset,VHDXImageType type)1583 vhdx_create_new_metadata(BlockBackend *blk, uint64_t image_size,
1584 uint32_t block_size, uint32_t sector_size,
1585 uint64_t metadata_offset, VHDXImageType type)
1586 {
1587 int ret = 0;
1588 uint32_t offset = 0;
1589 void *buffer = NULL;
1590 void *entry_buffer;
1591 VHDXMetadataTableHeader *md_table;
1592 VHDXMetadataTableEntry *md_table_entry;
1593
1594 /* Metadata entries */
1595 VHDXFileParameters *mt_file_params;
1596 VHDXVirtualDiskSize *mt_virtual_size;
1597 VHDXPage83Data *mt_page83;
1598 VHDXVirtualDiskLogicalSectorSize *mt_log_sector_size;
1599 VHDXVirtualDiskPhysicalSectorSize *mt_phys_sector_size;
1600
1601 entry_buffer = g_malloc0(VHDX_METADATA_ENTRY_BUFFER_SIZE);
1602
1603 mt_file_params = entry_buffer;
1604 offset += sizeof(VHDXFileParameters);
1605 mt_virtual_size = entry_buffer + offset;
1606 offset += sizeof(VHDXVirtualDiskSize);
1607 mt_page83 = entry_buffer + offset;
1608 offset += sizeof(VHDXPage83Data);
1609 mt_log_sector_size = entry_buffer + offset;
1610 offset += sizeof(VHDXVirtualDiskLogicalSectorSize);
1611 mt_phys_sector_size = entry_buffer + offset;
1612
1613 mt_file_params->block_size = cpu_to_le32(block_size);
1614 if (type == VHDX_TYPE_FIXED) {
1615 mt_file_params->data_bits |= VHDX_PARAMS_LEAVE_BLOCKS_ALLOCED;
1616 mt_file_params->data_bits = cpu_to_le32(mt_file_params->data_bits);
1617 }
1618
1619 vhdx_guid_generate(&mt_page83->page_83_data);
1620 cpu_to_leguids(&mt_page83->page_83_data);
1621 mt_virtual_size->virtual_disk_size = cpu_to_le64(image_size);
1622 mt_log_sector_size->logical_sector_size = cpu_to_le32(sector_size);
1623 mt_phys_sector_size->physical_sector_size = cpu_to_le32(sector_size);
1624
1625 buffer = g_malloc0(VHDX_HEADER_BLOCK_SIZE);
1626 md_table = buffer;
1627
1628 md_table->signature = VHDX_METADATA_SIGNATURE;
1629 md_table->entry_count = 5;
1630 vhdx_metadata_header_le_export(md_table);
1631
1632
1633 /* This will reference beyond the reserved table portion */
1634 offset = 64 * KiB;
1635
1636 md_table_entry = buffer + sizeof(VHDXMetadataTableHeader);
1637
1638 md_table_entry[0].item_id = file_param_guid;
1639 md_table_entry[0].offset = offset;
1640 md_table_entry[0].length = sizeof(VHDXFileParameters);
1641 md_table_entry[0].data_bits |= VHDX_META_FLAGS_IS_REQUIRED;
1642 offset += md_table_entry[0].length;
1643 vhdx_metadata_entry_le_export(&md_table_entry[0]);
1644
1645 md_table_entry[1].item_id = virtual_size_guid;
1646 md_table_entry[1].offset = offset;
1647 md_table_entry[1].length = sizeof(VHDXVirtualDiskSize);
1648 md_table_entry[1].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
1649 VHDX_META_FLAGS_IS_VIRTUAL_DISK;
1650 offset += md_table_entry[1].length;
1651 vhdx_metadata_entry_le_export(&md_table_entry[1]);
1652
1653 md_table_entry[2].item_id = page83_guid;
1654 md_table_entry[2].offset = offset;
1655 md_table_entry[2].length = sizeof(VHDXPage83Data);
1656 md_table_entry[2].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
1657 VHDX_META_FLAGS_IS_VIRTUAL_DISK;
1658 offset += md_table_entry[2].length;
1659 vhdx_metadata_entry_le_export(&md_table_entry[2]);
1660
1661 md_table_entry[3].item_id = logical_sector_guid;
1662 md_table_entry[3].offset = offset;
1663 md_table_entry[3].length = sizeof(VHDXVirtualDiskLogicalSectorSize);
1664 md_table_entry[3].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
1665 VHDX_META_FLAGS_IS_VIRTUAL_DISK;
1666 offset += md_table_entry[3].length;
1667 vhdx_metadata_entry_le_export(&md_table_entry[3]);
1668
1669 md_table_entry[4].item_id = phys_sector_guid;
1670 md_table_entry[4].offset = offset;
1671 md_table_entry[4].length = sizeof(VHDXVirtualDiskPhysicalSectorSize);
1672 md_table_entry[4].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
1673 VHDX_META_FLAGS_IS_VIRTUAL_DISK;
1674 vhdx_metadata_entry_le_export(&md_table_entry[4]);
1675
1676 ret = blk_co_pwrite(blk, metadata_offset, VHDX_HEADER_BLOCK_SIZE, buffer, 0);
1677 if (ret < 0) {
1678 goto exit;
1679 }
1680
1681 ret = blk_co_pwrite(blk, metadata_offset + (64 * KiB),
1682 VHDX_METADATA_ENTRY_BUFFER_SIZE, entry_buffer, 0);
1683 if (ret < 0) {
1684 goto exit;
1685 }
1686
1687
1688 exit:
1689 g_free(buffer);
1690 g_free(entry_buffer);
1691 return ret;
1692 }
1693
1694 /* This create the actual BAT itself. We currently only support
1695 * 'Dynamic' and 'Fixed' image types.
1696 *
1697 * Dynamic images: default state of the BAT is all zeroes.
1698 *
1699 * Fixed images: default state of the BAT is fully populated, with
1700 * file offsets and state PAYLOAD_BLOCK_FULLY_PRESENT.
1701 */
1702 static int coroutine_fn GRAPH_UNLOCKED
vhdx_create_bat(BlockBackend * blk,BDRVVHDXState * s,uint64_t image_size,VHDXImageType type,bool use_zero_blocks,uint64_t file_offset,uint32_t length,Error ** errp)1703 vhdx_create_bat(BlockBackend *blk, BDRVVHDXState *s,
1704 uint64_t image_size, VHDXImageType type,
1705 bool use_zero_blocks, uint64_t file_offset,
1706 uint32_t length, Error **errp)
1707 {
1708 int ret = 0;
1709 uint64_t data_file_offset;
1710 uint64_t total_sectors = 0;
1711 uint64_t sector_num = 0;
1712 uint64_t unused;
1713 int block_state;
1714 VHDXSectorInfo sinfo;
1715 bool has_zero_init;
1716
1717 assert(s->bat == NULL);
1718
1719 /* this gives a data start after BAT/bitmap entries, and well
1720 * past any metadata entries (with a 4 MB buffer for future
1721 * expansion */
1722 data_file_offset = file_offset + length + 5 * MiB;
1723 total_sectors = image_size >> s->logical_sector_size_bits;
1724
1725 if (type == VHDX_TYPE_DYNAMIC) {
1726 /* All zeroes, so we can just extend the file - the end of the BAT
1727 * is the furthest thing we have written yet */
1728 ret = blk_co_truncate(blk, data_file_offset, false, PREALLOC_MODE_OFF,
1729 0, errp);
1730 if (ret < 0) {
1731 goto exit;
1732 }
1733 } else if (type == VHDX_TYPE_FIXED) {
1734 ret = blk_co_truncate(blk, data_file_offset + image_size, false,
1735 PREALLOC_MODE_OFF, 0, errp);
1736 if (ret < 0) {
1737 goto exit;
1738 }
1739 } else {
1740 error_setg(errp, "Unsupported image type");
1741 ret = -ENOTSUP;
1742 goto exit;
1743 }
1744
1745 bdrv_graph_co_rdlock();
1746 has_zero_init = bdrv_has_zero_init(blk_bs(blk));
1747 bdrv_graph_co_rdunlock();
1748
1749 if (type == VHDX_TYPE_FIXED ||
1750 use_zero_blocks ||
1751 has_zero_init == 0) {
1752 /* for a fixed file, the default BAT entry is not zero */
1753 s->bat = g_try_malloc0(length);
1754 if (length && s->bat == NULL) {
1755 error_setg(errp, "Failed to allocate memory for the BAT");
1756 ret = -ENOMEM;
1757 goto exit;
1758 }
1759 block_state = type == VHDX_TYPE_FIXED ? PAYLOAD_BLOCK_FULLY_PRESENT :
1760 PAYLOAD_BLOCK_NOT_PRESENT;
1761 block_state = use_zero_blocks ? PAYLOAD_BLOCK_ZERO : block_state;
1762 /* fill the BAT by emulating sector writes of sectors_per_block size */
1763 while (sector_num < total_sectors) {
1764 vhdx_block_translate(s, sector_num, s->sectors_per_block, &sinfo);
1765 sinfo.file_offset = data_file_offset +
1766 (sector_num << s->logical_sector_size_bits);
1767 sinfo.file_offset = ROUND_UP(sinfo.file_offset, MiB);
1768 vhdx_update_bat_table_entry(blk_bs(blk), s, &sinfo, &unused, &unused,
1769 block_state);
1770 s->bat[sinfo.bat_idx] = cpu_to_le64(s->bat[sinfo.bat_idx]);
1771 sector_num += s->sectors_per_block;
1772 }
1773 ret = blk_co_pwrite(blk, file_offset, length, s->bat, 0);
1774 if (ret < 0) {
1775 error_setg_errno(errp, -ret, "Failed to write the BAT");
1776 goto exit;
1777 }
1778 }
1779
1780
1781
1782 exit:
1783 g_free(s->bat);
1784 return ret;
1785 }
1786
1787 /* Creates the region table header, and region table entries.
1788 * There are 2 supported region table entries: BAT, and Metadata/
1789 *
1790 * As the calculations for the BAT region table are also needed
1791 * to create the BAT itself, we will also cause the BAT to be
1792 * created.
1793 */
1794 static int coroutine_fn GRAPH_UNLOCKED
vhdx_create_new_region_table(BlockBackend * blk,uint64_t image_size,uint32_t block_size,uint32_t sector_size,uint32_t log_size,bool use_zero_blocks,VHDXImageType type,uint64_t * metadata_offset,Error ** errp)1795 vhdx_create_new_region_table(BlockBackend *blk, uint64_t image_size,
1796 uint32_t block_size, uint32_t sector_size,
1797 uint32_t log_size, bool use_zero_blocks,
1798 VHDXImageType type, uint64_t *metadata_offset,
1799 Error **errp)
1800 {
1801 int ret = 0;
1802 uint32_t offset = 0;
1803 void *buffer = NULL;
1804 uint64_t bat_file_offset;
1805 uint32_t bat_length;
1806 BDRVVHDXState *s = NULL;
1807 VHDXRegionTableHeader *region_table;
1808 VHDXRegionTableEntry *rt_bat;
1809 VHDXRegionTableEntry *rt_metadata;
1810
1811 assert(metadata_offset != NULL);
1812
1813 /* Populate enough of the BDRVVHDXState to be able to use the
1814 * pre-existing BAT calculation, translation, and update functions */
1815 s = g_new0(BDRVVHDXState, 1);
1816
1817 s->chunk_ratio = (VHDX_MAX_SECTORS_PER_BLOCK) *
1818 (uint64_t) sector_size / (uint64_t) block_size;
1819
1820 s->sectors_per_block = block_size / sector_size;
1821 s->virtual_disk_size = image_size;
1822 s->block_size = block_size;
1823 s->logical_sector_size = sector_size;
1824
1825 vhdx_set_shift_bits(s);
1826
1827 vhdx_calc_bat_entries(s);
1828
1829 /* At this point the VHDX state is populated enough for creation */
1830
1831 /* a single buffer is used so we can calculate the checksum over the
1832 * entire 64KB block */
1833 buffer = g_malloc0(VHDX_HEADER_BLOCK_SIZE);
1834 region_table = buffer;
1835 offset += sizeof(VHDXRegionTableHeader);
1836 rt_bat = buffer + offset;
1837 offset += sizeof(VHDXRegionTableEntry);
1838 rt_metadata = buffer + offset;
1839
1840 region_table->signature = VHDX_REGION_SIGNATURE;
1841 region_table->entry_count = 2; /* BAT and Metadata */
1842
1843 rt_bat->guid = bat_guid;
1844 rt_bat->length = ROUND_UP(s->bat_entries * sizeof(VHDXBatEntry), MiB);
1845 rt_bat->file_offset = ROUND_UP(VHDX_HEADER_SECTION_END + log_size, MiB);
1846 s->bat_offset = rt_bat->file_offset;
1847
1848 rt_metadata->guid = metadata_guid;
1849 rt_metadata->file_offset = ROUND_UP(rt_bat->file_offset + rt_bat->length,
1850 MiB);
1851 rt_metadata->length = 1 * MiB; /* min size, and more than enough */
1852 *metadata_offset = rt_metadata->file_offset;
1853
1854 bat_file_offset = rt_bat->file_offset;
1855 bat_length = rt_bat->length;
1856
1857 vhdx_region_header_le_export(region_table);
1858 vhdx_region_entry_le_export(rt_bat);
1859 vhdx_region_entry_le_export(rt_metadata);
1860
1861 vhdx_update_checksum(buffer, VHDX_HEADER_BLOCK_SIZE,
1862 offsetof(VHDXRegionTableHeader, checksum));
1863
1864
1865 /* The region table gives us the data we need to create the BAT,
1866 * so do that now */
1867 ret = vhdx_create_bat(blk, s, image_size, type, use_zero_blocks,
1868 bat_file_offset, bat_length, errp);
1869 if (ret < 0) {
1870 goto exit;
1871 }
1872
1873 /* Now write out the region headers to disk */
1874 ret = blk_co_pwrite(blk, VHDX_REGION_TABLE_OFFSET, VHDX_HEADER_BLOCK_SIZE,
1875 buffer, 0);
1876 if (ret < 0) {
1877 error_setg_errno(errp, -ret, "Failed to write first region table");
1878 goto exit;
1879 }
1880
1881 ret = blk_co_pwrite(blk, VHDX_REGION_TABLE2_OFFSET, VHDX_HEADER_BLOCK_SIZE,
1882 buffer, 0);
1883 if (ret < 0) {
1884 error_setg_errno(errp, -ret, "Failed to write second region table");
1885 goto exit;
1886 }
1887
1888 exit:
1889 g_free(s);
1890 g_free(buffer);
1891 return ret;
1892 }
1893
1894 /* We need to create the following elements:
1895 *
1896 * .-----------------------------------------------------------------.
1897 * | (A) | (B) | (C) | (D) | (E) |
1898 * | File ID | Header1 | Header 2 | Region Tbl 1 | Region Tbl 2 |
1899 * | | | | | |
1900 * .-----------------------------------------------------------------.
1901 * 0 64KB 128KB 192KB 256KB 320KB
1902 *
1903 *
1904 * .---- ~ ----------- ~ ------------ ~ ---------------- ~ -----------.
1905 * | (F) | (G) | (H) | |
1906 * | Journal Log | BAT / Bitmap | Metadata | .... data ...... |
1907 * | | | | |
1908 * .---- ~ ----------- ~ ------------ ~ ---------------- ~ -----------.
1909 * 1MB
1910 */
1911 static int coroutine_fn GRAPH_UNLOCKED
vhdx_co_create(BlockdevCreateOptions * opts,Error ** errp)1912 vhdx_co_create(BlockdevCreateOptions *opts, Error **errp)
1913 {
1914 BlockdevCreateOptionsVhdx *vhdx_opts;
1915 BlockBackend *blk = NULL;
1916 BlockDriverState *bs = NULL;
1917
1918 int ret = 0;
1919 uint64_t image_size;
1920 uint32_t log_size;
1921 uint32_t block_size;
1922 uint64_t signature;
1923 uint64_t metadata_offset;
1924 bool use_zero_blocks = false;
1925
1926 gunichar2 *creator = NULL;
1927 glong creator_items;
1928 VHDXImageType image_type;
1929
1930 assert(opts->driver == BLOCKDEV_DRIVER_VHDX);
1931 vhdx_opts = &opts->u.vhdx;
1932
1933 /* Validate options and set default values */
1934 image_size = vhdx_opts->size;
1935 if (image_size > VHDX_MAX_IMAGE_SIZE) {
1936 error_setg(errp, "Image size too large; max of 64TB");
1937 return -EINVAL;
1938 }
1939
1940 if (!vhdx_opts->has_log_size) {
1941 log_size = DEFAULT_LOG_SIZE;
1942 } else {
1943 if (vhdx_opts->log_size > UINT32_MAX) {
1944 error_setg(errp, "Log size must be smaller than 4 GB");
1945 return -EINVAL;
1946 }
1947 log_size = vhdx_opts->log_size;
1948 }
1949 if (log_size < MiB || (log_size % MiB) != 0) {
1950 error_setg(errp, "Log size must be a multiple of 1 MB");
1951 return -EINVAL;
1952 }
1953
1954 if (!vhdx_opts->has_block_state_zero) {
1955 use_zero_blocks = true;
1956 } else {
1957 use_zero_blocks = vhdx_opts->block_state_zero;
1958 }
1959
1960 if (!vhdx_opts->has_subformat) {
1961 vhdx_opts->subformat = BLOCKDEV_VHDX_SUBFORMAT_DYNAMIC;
1962 }
1963
1964 switch (vhdx_opts->subformat) {
1965 case BLOCKDEV_VHDX_SUBFORMAT_DYNAMIC:
1966 image_type = VHDX_TYPE_DYNAMIC;
1967 break;
1968 case BLOCKDEV_VHDX_SUBFORMAT_FIXED:
1969 image_type = VHDX_TYPE_FIXED;
1970 break;
1971 default:
1972 g_assert_not_reached();
1973 }
1974
1975 /* These are pretty arbitrary, and mainly designed to keep the BAT
1976 * size reasonable to load into RAM */
1977 if (vhdx_opts->has_block_size) {
1978 block_size = vhdx_opts->block_size;
1979 } else {
1980 if (image_size > 32 * TiB) {
1981 block_size = 64 * MiB;
1982 } else if (image_size > (uint64_t) 100 * GiB) {
1983 block_size = 32 * MiB;
1984 } else if (image_size > 1 * GiB) {
1985 block_size = 16 * MiB;
1986 } else {
1987 block_size = 8 * MiB;
1988 }
1989 }
1990
1991 if (block_size < MiB || (block_size % MiB) != 0) {
1992 error_setg(errp, "Block size must be a multiple of 1 MB");
1993 return -EINVAL;
1994 }
1995 if (!is_power_of_2(block_size)) {
1996 error_setg(errp, "Block size must be a power of two");
1997 return -EINVAL;
1998 }
1999 if (block_size > VHDX_BLOCK_SIZE_MAX) {
2000 error_setg(errp, "Block size must not exceed %" PRId64,
2001 VHDX_BLOCK_SIZE_MAX);
2002 return -EINVAL;
2003 }
2004
2005 /* Create BlockBackend to write to the image */
2006 bs = bdrv_co_open_blockdev_ref(vhdx_opts->file, errp);
2007 if (bs == NULL) {
2008 return -EIO;
2009 }
2010
2011 blk = blk_co_new_with_bs(bs, BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL,
2012 errp);
2013 if (!blk) {
2014 ret = -EPERM;
2015 goto delete_and_exit;
2016 }
2017 blk_set_allow_write_beyond_eof(blk, true);
2018
2019 /* Create (A) */
2020
2021 /* The creator field is optional, but may be useful for
2022 * debugging / diagnostics */
2023 creator = g_utf8_to_utf16("QEMU v" QEMU_VERSION, -1, NULL,
2024 &creator_items, NULL);
2025 signature = cpu_to_le64(VHDX_FILE_SIGNATURE);
2026 ret = blk_co_pwrite(blk, VHDX_FILE_ID_OFFSET, sizeof(signature), &signature,
2027 0);
2028 if (ret < 0) {
2029 error_setg_errno(errp, -ret, "Failed to write file signature");
2030 goto delete_and_exit;
2031 }
2032 if (creator) {
2033 ret = blk_co_pwrite(blk, VHDX_FILE_ID_OFFSET + sizeof(signature),
2034 creator_items * sizeof(gunichar2), creator, 0);
2035 if (ret < 0) {
2036 error_setg_errno(errp, -ret, "Failed to write creator field");
2037 goto delete_and_exit;
2038 }
2039 }
2040
2041
2042 /* Creates (B),(C) */
2043 ret = vhdx_create_new_headers(blk, image_size, log_size);
2044 if (ret < 0) {
2045 error_setg_errno(errp, -ret, "Failed to write image headers");
2046 goto delete_and_exit;
2047 }
2048
2049 /* Creates (D),(E),(G) explicitly. (F) created as by-product */
2050 ret = vhdx_create_new_region_table(blk, image_size, block_size, 512,
2051 log_size, use_zero_blocks, image_type,
2052 &metadata_offset, errp);
2053 if (ret < 0) {
2054 goto delete_and_exit;
2055 }
2056
2057 /* Creates (H) */
2058 ret = vhdx_create_new_metadata(blk, image_size, block_size, 512,
2059 metadata_offset, image_type);
2060 if (ret < 0) {
2061 error_setg_errno(errp, -ret, "Failed to initialize metadata");
2062 goto delete_and_exit;
2063 }
2064
2065 ret = 0;
2066 delete_and_exit:
2067 blk_co_unref(blk);
2068 bdrv_co_unref(bs);
2069 g_free(creator);
2070 return ret;
2071 }
2072
2073 static int coroutine_fn GRAPH_UNLOCKED
vhdx_co_create_opts(BlockDriver * drv,const char * filename,QemuOpts * opts,Error ** errp)2074 vhdx_co_create_opts(BlockDriver *drv, const char *filename,
2075 QemuOpts *opts, Error **errp)
2076 {
2077 BlockdevCreateOptions *create_options = NULL;
2078 QDict *qdict;
2079 Visitor *v;
2080 BlockDriverState *bs = NULL;
2081 int ret;
2082
2083 static const QDictRenames opt_renames[] = {
2084 { VHDX_BLOCK_OPT_LOG_SIZE, "log-size" },
2085 { VHDX_BLOCK_OPT_BLOCK_SIZE, "block-size" },
2086 { VHDX_BLOCK_OPT_ZERO, "block-state-zero" },
2087 { NULL, NULL },
2088 };
2089
2090 /* Parse options and convert legacy syntax */
2091 qdict = qemu_opts_to_qdict_filtered(opts, NULL, &vhdx_create_opts, true);
2092
2093 if (!qdict_rename_keys(qdict, opt_renames, errp)) {
2094 ret = -EINVAL;
2095 goto fail;
2096 }
2097
2098 /* Create and open the file (protocol layer) */
2099 ret = bdrv_co_create_file(filename, opts, errp);
2100 if (ret < 0) {
2101 goto fail;
2102 }
2103
2104 bs = bdrv_co_open(filename, NULL, NULL,
2105 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp);
2106 if (bs == NULL) {
2107 ret = -EIO;
2108 goto fail;
2109 }
2110
2111 /* Now get the QAPI type BlockdevCreateOptions */
2112 qdict_put_str(qdict, "driver", "vhdx");
2113 qdict_put_str(qdict, "file", bs->node_name);
2114
2115 v = qobject_input_visitor_new_flat_confused(qdict, errp);
2116 if (!v) {
2117 ret = -EINVAL;
2118 goto fail;
2119 }
2120
2121 visit_type_BlockdevCreateOptions(v, NULL, &create_options, errp);
2122 visit_free(v);
2123 if (!create_options) {
2124 ret = -EINVAL;
2125 goto fail;
2126 }
2127
2128 /* Silently round up sizes:
2129 * The image size is rounded to 512 bytes. Make the block and log size
2130 * close to what was specified, but must be at least 1MB, and a multiple of
2131 * 1 MB. Also respect VHDX_BLOCK_SIZE_MAX for block sizes. block_size = 0
2132 * means auto, which is represented by a missing key in QAPI. */
2133 assert(create_options->driver == BLOCKDEV_DRIVER_VHDX);
2134 create_options->u.vhdx.size =
2135 ROUND_UP(create_options->u.vhdx.size, BDRV_SECTOR_SIZE);
2136
2137 if (create_options->u.vhdx.has_log_size) {
2138 create_options->u.vhdx.log_size =
2139 ROUND_UP(create_options->u.vhdx.log_size, MiB);
2140 }
2141 if (create_options->u.vhdx.has_block_size) {
2142 create_options->u.vhdx.block_size =
2143 ROUND_UP(create_options->u.vhdx.block_size, MiB);
2144
2145 if (create_options->u.vhdx.block_size == 0) {
2146 create_options->u.vhdx.has_block_size = false;
2147 }
2148 if (create_options->u.vhdx.block_size > VHDX_BLOCK_SIZE_MAX) {
2149 create_options->u.vhdx.block_size = VHDX_BLOCK_SIZE_MAX;
2150 }
2151 }
2152
2153 /* Create the vhdx image (format layer) */
2154 ret = vhdx_co_create(create_options, errp);
2155
2156 fail:
2157 qobject_unref(qdict);
2158 bdrv_co_unref(bs);
2159 qapi_free_BlockdevCreateOptions(create_options);
2160 return ret;
2161 }
2162
2163 /* If opened r/w, the VHDX driver will automatically replay the log,
2164 * if one is present, inside the vhdx_open() call.
2165 *
2166 * If qemu-img check -r all is called, the image is automatically opened
2167 * r/w and any log has already been replayed, so there is nothing (currently)
2168 * for us to do here
2169 */
2170 static int coroutine_fn GRAPH_RDLOCK
vhdx_co_check(BlockDriverState * bs,BdrvCheckResult * result,BdrvCheckMode fix)2171 vhdx_co_check(BlockDriverState *bs, BdrvCheckResult *result,
2172 BdrvCheckMode fix)
2173 {
2174 BDRVVHDXState *s = bs->opaque;
2175
2176 if (s->log_replayed_on_open) {
2177 result->corruptions_fixed++;
2178 }
2179
2180 vhdx_check_bat_entries(bs, &result->corruptions);
2181
2182 return 0;
2183 }
2184
vhdx_has_zero_init(BlockDriverState * bs)2185 static int GRAPH_RDLOCK vhdx_has_zero_init(BlockDriverState *bs)
2186 {
2187 BDRVVHDXState *s = bs->opaque;
2188 int state;
2189
2190 /*
2191 * Check the subformat: Fixed images have all BAT entries present,
2192 * dynamic images have none (right after creation). It is
2193 * therefore enough to check the first BAT entry.
2194 */
2195 if (!s->bat_entries) {
2196 return 1;
2197 }
2198
2199 state = s->bat[0] & VHDX_BAT_STATE_BIT_MASK;
2200 if (state == PAYLOAD_BLOCK_FULLY_PRESENT) {
2201 /* Fixed subformat */
2202 return bdrv_has_zero_init(bs->file->bs);
2203 }
2204
2205 /* Dynamic subformat */
2206 return 1;
2207 }
2208
2209 static QemuOptsList vhdx_create_opts = {
2210 .name = "vhdx-create-opts",
2211 .head = QTAILQ_HEAD_INITIALIZER(vhdx_create_opts.head),
2212 .desc = {
2213 {
2214 .name = BLOCK_OPT_SIZE,
2215 .type = QEMU_OPT_SIZE,
2216 .help = "Virtual disk size; max of 64TB."
2217 },
2218 {
2219 .name = VHDX_BLOCK_OPT_LOG_SIZE,
2220 .type = QEMU_OPT_SIZE,
2221 .def_value_str = stringify(DEFAULT_LOG_SIZE),
2222 .help = "Log size; min 1MB."
2223 },
2224 {
2225 .name = VHDX_BLOCK_OPT_BLOCK_SIZE,
2226 .type = QEMU_OPT_SIZE,
2227 .def_value_str = stringify(0),
2228 .help = "Block Size; min 1MB, max 256MB. "
2229 "0 means auto-calculate based on image size."
2230 },
2231 {
2232 .name = BLOCK_OPT_SUBFMT,
2233 .type = QEMU_OPT_STRING,
2234 .help = "VHDX format type, can be either 'dynamic' or 'fixed'. "
2235 "Default is 'dynamic'."
2236 },
2237 {
2238 .name = VHDX_BLOCK_OPT_ZERO,
2239 .type = QEMU_OPT_BOOL,
2240 .help = "Force use of payload blocks of type 'ZERO'. "
2241 "Non-standard, but default. Do not set to 'off' when "
2242 "using 'qemu-img convert' with subformat=dynamic."
2243 },
2244 { NULL }
2245 }
2246 };
2247
2248 static BlockDriver bdrv_vhdx = {
2249 .format_name = "vhdx",
2250 .instance_size = sizeof(BDRVVHDXState),
2251 .bdrv_probe = vhdx_probe,
2252 .bdrv_open = vhdx_open,
2253 .bdrv_close = vhdx_close,
2254 .bdrv_reopen_prepare = vhdx_reopen_prepare,
2255 .bdrv_child_perm = bdrv_default_perms,
2256 .bdrv_co_readv = vhdx_co_readv,
2257 .bdrv_co_writev = vhdx_co_writev,
2258 .bdrv_co_create = vhdx_co_create,
2259 .bdrv_co_create_opts = vhdx_co_create_opts,
2260 .bdrv_co_get_info = vhdx_co_get_info,
2261 .bdrv_co_check = vhdx_co_check,
2262 .bdrv_has_zero_init = vhdx_has_zero_init,
2263
2264 .is_format = true,
2265 .create_opts = &vhdx_create_opts,
2266 };
2267
bdrv_vhdx_init(void)2268 static void bdrv_vhdx_init(void)
2269 {
2270 bdrv_register(&bdrv_vhdx);
2271 }
2272
2273 block_init(bdrv_vhdx_init);
2274