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 v0.95", published 4/12/2012 10 * by Microsoft: 11 * https://www.microsoft.com/en-us/download/details.aspx?id=29681 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-common.h" 19 #include "block/block_int.h" 20 #include "qemu/module.h" 21 #include "qemu/crc32c.h" 22 #include "block/vhdx.h" 23 24 25 /* Several metadata and region table data entries are identified by 26 * guids in a MS-specific GUID format. */ 27 28 29 /* ------- Known Region Table GUIDs ---------------------- */ 30 static const MSGUID bat_guid = { .data1 = 0x2dc27766, 31 .data2 = 0xf623, 32 .data3 = 0x4200, 33 .data4 = { 0x9d, 0x64, 0x11, 0x5e, 34 0x9b, 0xfd, 0x4a, 0x08} }; 35 36 static const MSGUID metadata_guid = { .data1 = 0x8b7ca206, 37 .data2 = 0x4790, 38 .data3 = 0x4b9a, 39 .data4 = { 0xb8, 0xfe, 0x57, 0x5f, 40 0x05, 0x0f, 0x88, 0x6e} }; 41 42 43 44 /* ------- Known Metadata Entry GUIDs ---------------------- */ 45 static const MSGUID file_param_guid = { .data1 = 0xcaa16737, 46 .data2 = 0xfa36, 47 .data3 = 0x4d43, 48 .data4 = { 0xb3, 0xb6, 0x33, 0xf0, 49 0xaa, 0x44, 0xe7, 0x6b} }; 50 51 static const MSGUID virtual_size_guid = { .data1 = 0x2FA54224, 52 .data2 = 0xcd1b, 53 .data3 = 0x4876, 54 .data4 = { 0xb2, 0x11, 0x5d, 0xbe, 55 0xd8, 0x3b, 0xf4, 0xb8} }; 56 57 static const MSGUID page83_guid = { .data1 = 0xbeca12ab, 58 .data2 = 0xb2e6, 59 .data3 = 0x4523, 60 .data4 = { 0x93, 0xef, 0xc3, 0x09, 61 0xe0, 0x00, 0xc7, 0x46} }; 62 63 64 static const MSGUID phys_sector_guid = { .data1 = 0xcda348c7, 65 .data2 = 0x445d, 66 .data3 = 0x4471, 67 .data4 = { 0x9c, 0xc9, 0xe9, 0x88, 68 0x52, 0x51, 0xc5, 0x56} }; 69 70 static const MSGUID parent_locator_guid = { .data1 = 0xa8d35f2d, 71 .data2 = 0xb30b, 72 .data3 = 0x454d, 73 .data4 = { 0xab, 0xf7, 0xd3, 74 0xd8, 0x48, 0x34, 75 0xab, 0x0c} }; 76 77 static const MSGUID logical_sector_guid = { .data1 = 0x8141bf1d, 78 .data2 = 0xa96f, 79 .data3 = 0x4709, 80 .data4 = { 0xba, 0x47, 0xf2, 81 0x33, 0xa8, 0xfa, 82 0xab, 0x5f} }; 83 84 /* Each parent type must have a valid GUID; this is for parent images 85 * of type 'VHDX'. If we were to allow e.g. a QCOW2 parent, we would 86 * need to make up our own QCOW2 GUID type */ 87 static const MSGUID parent_vhdx_guid = { .data1 = 0xb04aefb7, 88 .data2 = 0xd19e, 89 .data3 = 0x4a81, 90 .data4 = { 0xb7, 0x89, 0x25, 0xb8, 91 0xe9, 0x44, 0x59, 0x13} }; 92 93 94 #define META_FILE_PARAMETER_PRESENT 0x01 95 #define META_VIRTUAL_DISK_SIZE_PRESENT 0x02 96 #define META_PAGE_83_PRESENT 0x04 97 #define META_LOGICAL_SECTOR_SIZE_PRESENT 0x08 98 #define META_PHYS_SECTOR_SIZE_PRESENT 0x10 99 #define META_PARENT_LOCATOR_PRESENT 0x20 100 101 #define META_ALL_PRESENT \ 102 (META_FILE_PARAMETER_PRESENT | META_VIRTUAL_DISK_SIZE_PRESENT | \ 103 META_PAGE_83_PRESENT | META_LOGICAL_SECTOR_SIZE_PRESENT | \ 104 META_PHYS_SECTOR_SIZE_PRESENT) 105 106 typedef struct VHDXMetadataEntries { 107 VHDXMetadataTableEntry file_parameters_entry; 108 VHDXMetadataTableEntry virtual_disk_size_entry; 109 VHDXMetadataTableEntry page83_data_entry; 110 VHDXMetadataTableEntry logical_sector_size_entry; 111 VHDXMetadataTableEntry phys_sector_size_entry; 112 VHDXMetadataTableEntry parent_locator_entry; 113 uint16_t present; 114 } VHDXMetadataEntries; 115 116 117 typedef struct VHDXSectorInfo { 118 uint32_t bat_idx; /* BAT entry index */ 119 uint32_t sectors_avail; /* sectors available in payload block */ 120 uint32_t bytes_left; /* bytes left in the block after data to r/w */ 121 uint32_t bytes_avail; /* bytes available in payload block */ 122 uint64_t file_offset; /* absolute offset in bytes, in file */ 123 uint64_t block_offset; /* block offset, in bytes */ 124 } VHDXSectorInfo; 125 126 127 128 typedef struct BDRVVHDXState { 129 CoMutex lock; 130 131 int curr_header; 132 VHDXHeader *headers[2]; 133 134 VHDXRegionTableHeader rt; 135 VHDXRegionTableEntry bat_rt; /* region table for the BAT */ 136 VHDXRegionTableEntry metadata_rt; /* region table for the metadata */ 137 138 VHDXMetadataTableHeader metadata_hdr; 139 VHDXMetadataEntries metadata_entries; 140 141 VHDXFileParameters params; 142 uint32_t block_size; 143 uint32_t block_size_bits; 144 uint32_t sectors_per_block; 145 uint32_t sectors_per_block_bits; 146 147 uint64_t virtual_disk_size; 148 uint32_t logical_sector_size; 149 uint32_t physical_sector_size; 150 151 uint64_t chunk_ratio; 152 uint32_t chunk_ratio_bits; 153 uint32_t logical_sector_size_bits; 154 155 uint32_t bat_entries; 156 VHDXBatEntry *bat; 157 uint64_t bat_offset; 158 159 VHDXParentLocatorHeader parent_header; 160 VHDXParentLocatorEntry *parent_entries; 161 162 } BDRVVHDXState; 163 164 uint32_t vhdx_checksum_calc(uint32_t crc, uint8_t *buf, size_t size, 165 int crc_offset) 166 { 167 uint32_t crc_new; 168 uint32_t crc_orig; 169 assert(buf != NULL); 170 171 if (crc_offset > 0) { 172 memcpy(&crc_orig, buf + crc_offset, sizeof(crc_orig)); 173 memset(buf + crc_offset, 0, sizeof(crc_orig)); 174 } 175 176 crc_new = crc32c(crc, buf, size); 177 if (crc_offset > 0) { 178 memcpy(buf + crc_offset, &crc_orig, sizeof(crc_orig)); 179 } 180 181 return crc_new; 182 } 183 184 /* Validates the checksum of the buffer, with an in-place CRC. 185 * 186 * Zero is substituted during crc calculation for the original crc field, 187 * and the crc field is restored afterwards. But the buffer will be modifed 188 * during the calculation, so this may not be not suitable for multi-threaded 189 * use. 190 * 191 * crc_offset: byte offset in buf of the buffer crc 192 * buf: buffer pointer 193 * size: size of buffer (must be > crc_offset+4) 194 * 195 * returns true if checksum is valid, false otherwise 196 */ 197 bool vhdx_checksum_is_valid(uint8_t *buf, size_t size, int crc_offset) 198 { 199 uint32_t crc_orig; 200 uint32_t crc; 201 202 assert(buf != NULL); 203 assert(size > (crc_offset + 4)); 204 205 memcpy(&crc_orig, buf + crc_offset, sizeof(crc_orig)); 206 crc_orig = le32_to_cpu(crc_orig); 207 208 crc = vhdx_checksum_calc(0xffffffff, buf, size, crc_offset); 209 210 return crc == crc_orig; 211 } 212 213 214 /* 215 * Per the MS VHDX Specification, for every VHDX file: 216 * - The header section is fixed size - 1 MB 217 * - The header section is always the first "object" 218 * - The first 64KB of the header is the File Identifier 219 * - The first uint64 (8 bytes) is the VHDX Signature ("vhdxfile") 220 * - The following 512 bytes constitute a UTF-16 string identifiying the 221 * software that created the file, and is optional and diagnostic only. 222 * 223 * Therefore, we probe by looking for the vhdxfile signature "vhdxfile" 224 */ 225 static int vhdx_probe(const uint8_t *buf, int buf_size, const char *filename) 226 { 227 if (buf_size >= 8 && !memcmp(buf, "vhdxfile", 8)) { 228 return 100; 229 } 230 return 0; 231 } 232 233 /* All VHDX structures on disk are little endian */ 234 static void vhdx_header_le_import(VHDXHeader *h) 235 { 236 assert(h != NULL); 237 238 le32_to_cpus(&h->signature); 239 le32_to_cpus(&h->checksum); 240 le64_to_cpus(&h->sequence_number); 241 242 leguid_to_cpus(&h->file_write_guid); 243 leguid_to_cpus(&h->data_write_guid); 244 leguid_to_cpus(&h->log_guid); 245 246 le16_to_cpus(&h->log_version); 247 le16_to_cpus(&h->version); 248 le32_to_cpus(&h->log_length); 249 le64_to_cpus(&h->log_offset); 250 } 251 252 253 /* opens the specified header block from the VHDX file header section */ 254 static int vhdx_parse_header(BlockDriverState *bs, BDRVVHDXState *s) 255 { 256 int ret = 0; 257 VHDXHeader *header1; 258 VHDXHeader *header2; 259 bool h1_valid = false; 260 bool h2_valid = false; 261 uint64_t h1_seq = 0; 262 uint64_t h2_seq = 0; 263 uint8_t *buffer; 264 265 header1 = qemu_blockalign(bs, sizeof(VHDXHeader)); 266 header2 = qemu_blockalign(bs, sizeof(VHDXHeader)); 267 268 buffer = qemu_blockalign(bs, VHDX_HEADER_SIZE); 269 270 s->headers[0] = header1; 271 s->headers[1] = header2; 272 273 /* We have to read the whole VHDX_HEADER_SIZE instead of 274 * sizeof(VHDXHeader), because the checksum is over the whole 275 * region */ 276 ret = bdrv_pread(bs->file, VHDX_HEADER1_OFFSET, buffer, VHDX_HEADER_SIZE); 277 if (ret < 0) { 278 goto fail; 279 } 280 /* copy over just the relevant portion that we need */ 281 memcpy(header1, buffer, sizeof(VHDXHeader)); 282 vhdx_header_le_import(header1); 283 284 if (vhdx_checksum_is_valid(buffer, VHDX_HEADER_SIZE, 4) && 285 !memcmp(&header1->signature, "head", 4) && 286 header1->version == 1) { 287 h1_seq = header1->sequence_number; 288 h1_valid = true; 289 } 290 291 ret = bdrv_pread(bs->file, VHDX_HEADER2_OFFSET, buffer, VHDX_HEADER_SIZE); 292 if (ret < 0) { 293 goto fail; 294 } 295 /* copy over just the relevant portion that we need */ 296 memcpy(header2, buffer, sizeof(VHDXHeader)); 297 vhdx_header_le_import(header2); 298 299 if (vhdx_checksum_is_valid(buffer, VHDX_HEADER_SIZE, 4) && 300 !memcmp(&header2->signature, "head", 4) && 301 header2->version == 1) { 302 h2_seq = header2->sequence_number; 303 h2_valid = true; 304 } 305 306 /* If there is only 1 valid header (or no valid headers), we 307 * don't care what the sequence numbers are */ 308 if (h1_valid && !h2_valid) { 309 s->curr_header = 0; 310 } else if (!h1_valid && h2_valid) { 311 s->curr_header = 1; 312 } else if (!h1_valid && !h2_valid) { 313 ret = -EINVAL; 314 goto fail; 315 } else { 316 /* If both headers are valid, then we choose the active one by the 317 * highest sequence number. If the sequence numbers are equal, that is 318 * invalid */ 319 if (h1_seq > h2_seq) { 320 s->curr_header = 0; 321 } else if (h2_seq > h1_seq) { 322 s->curr_header = 1; 323 } else { 324 ret = -EINVAL; 325 goto fail; 326 } 327 } 328 329 ret = 0; 330 331 goto exit; 332 333 fail: 334 qerror_report(ERROR_CLASS_GENERIC_ERROR, "No valid VHDX header found"); 335 qemu_vfree(header1); 336 qemu_vfree(header2); 337 s->headers[0] = NULL; 338 s->headers[1] = NULL; 339 exit: 340 qemu_vfree(buffer); 341 return ret; 342 } 343 344 345 static int vhdx_open_region_tables(BlockDriverState *bs, BDRVVHDXState *s) 346 { 347 int ret = 0; 348 uint8_t *buffer; 349 int offset = 0; 350 VHDXRegionTableEntry rt_entry; 351 uint32_t i; 352 bool bat_rt_found = false; 353 bool metadata_rt_found = false; 354 355 /* We have to read the whole 64KB block, because the crc32 is over the 356 * whole block */ 357 buffer = qemu_blockalign(bs, VHDX_HEADER_BLOCK_SIZE); 358 359 ret = bdrv_pread(bs->file, VHDX_REGION_TABLE_OFFSET, buffer, 360 VHDX_HEADER_BLOCK_SIZE); 361 if (ret < 0) { 362 goto fail; 363 } 364 memcpy(&s->rt, buffer, sizeof(s->rt)); 365 le32_to_cpus(&s->rt.signature); 366 le32_to_cpus(&s->rt.checksum); 367 le32_to_cpus(&s->rt.entry_count); 368 le32_to_cpus(&s->rt.reserved); 369 offset += sizeof(s->rt); 370 371 if (!vhdx_checksum_is_valid(buffer, VHDX_HEADER_BLOCK_SIZE, 4) || 372 memcmp(&s->rt.signature, "regi", 4)) { 373 ret = -EINVAL; 374 goto fail; 375 } 376 377 /* Per spec, maximum region table entry count is 2047 */ 378 if (s->rt.entry_count > 2047) { 379 ret = -EINVAL; 380 goto fail; 381 } 382 383 for (i = 0; i < s->rt.entry_count; i++) { 384 memcpy(&rt_entry, buffer + offset, sizeof(rt_entry)); 385 offset += sizeof(rt_entry); 386 387 leguid_to_cpus(&rt_entry.guid); 388 le64_to_cpus(&rt_entry.file_offset); 389 le32_to_cpus(&rt_entry.length); 390 le32_to_cpus(&rt_entry.data_bits); 391 392 /* see if we recognize the entry */ 393 if (guid_eq(rt_entry.guid, bat_guid)) { 394 /* must be unique; if we have already found it this is invalid */ 395 if (bat_rt_found) { 396 ret = -EINVAL; 397 goto fail; 398 } 399 bat_rt_found = true; 400 s->bat_rt = rt_entry; 401 continue; 402 } 403 404 if (guid_eq(rt_entry.guid, metadata_guid)) { 405 /* must be unique; if we have already found it this is invalid */ 406 if (metadata_rt_found) { 407 ret = -EINVAL; 408 goto fail; 409 } 410 metadata_rt_found = true; 411 s->metadata_rt = rt_entry; 412 continue; 413 } 414 415 if (rt_entry.data_bits & VHDX_REGION_ENTRY_REQUIRED) { 416 /* cannot read vhdx file - required region table entry that 417 * we do not understand. per spec, we must fail to open */ 418 ret = -ENOTSUP; 419 goto fail; 420 } 421 } 422 ret = 0; 423 424 fail: 425 qemu_vfree(buffer); 426 return ret; 427 } 428 429 430 431 /* Metadata initial parser 432 * 433 * This loads all the metadata entry fields. This may cause additional 434 * fields to be processed (e.g. parent locator, etc..). 435 * 436 * There are 5 Metadata items that are always required: 437 * - File Parameters (block size, has a parent) 438 * - Virtual Disk Size (size, in bytes, of the virtual drive) 439 * - Page 83 Data (scsi page 83 guid) 440 * - Logical Sector Size (logical sector size in bytes, either 512 or 441 * 4096. We only support 512 currently) 442 * - Physical Sector Size (512 or 4096) 443 * 444 * Also, if the File Parameters indicate this is a differencing file, 445 * we must also look for the Parent Locator metadata item. 446 */ 447 static int vhdx_parse_metadata(BlockDriverState *bs, BDRVVHDXState *s) 448 { 449 int ret = 0; 450 uint8_t *buffer; 451 int offset = 0; 452 uint32_t i = 0; 453 VHDXMetadataTableEntry md_entry; 454 455 buffer = qemu_blockalign(bs, VHDX_METADATA_TABLE_MAX_SIZE); 456 457 ret = bdrv_pread(bs->file, s->metadata_rt.file_offset, buffer, 458 VHDX_METADATA_TABLE_MAX_SIZE); 459 if (ret < 0) { 460 goto exit; 461 } 462 memcpy(&s->metadata_hdr, buffer, sizeof(s->metadata_hdr)); 463 offset += sizeof(s->metadata_hdr); 464 465 le64_to_cpus(&s->metadata_hdr.signature); 466 le16_to_cpus(&s->metadata_hdr.reserved); 467 le16_to_cpus(&s->metadata_hdr.entry_count); 468 469 if (memcmp(&s->metadata_hdr.signature, "metadata", 8)) { 470 ret = -EINVAL; 471 goto exit; 472 } 473 474 s->metadata_entries.present = 0; 475 476 if ((s->metadata_hdr.entry_count * sizeof(md_entry)) > 477 (VHDX_METADATA_TABLE_MAX_SIZE - offset)) { 478 ret = -EINVAL; 479 goto exit; 480 } 481 482 for (i = 0; i < s->metadata_hdr.entry_count; i++) { 483 memcpy(&md_entry, buffer + offset, sizeof(md_entry)); 484 offset += sizeof(md_entry); 485 486 leguid_to_cpus(&md_entry.item_id); 487 le32_to_cpus(&md_entry.offset); 488 le32_to_cpus(&md_entry.length); 489 le32_to_cpus(&md_entry.data_bits); 490 le32_to_cpus(&md_entry.reserved2); 491 492 if (guid_eq(md_entry.item_id, file_param_guid)) { 493 if (s->metadata_entries.present & META_FILE_PARAMETER_PRESENT) { 494 ret = -EINVAL; 495 goto exit; 496 } 497 s->metadata_entries.file_parameters_entry = md_entry; 498 s->metadata_entries.present |= META_FILE_PARAMETER_PRESENT; 499 continue; 500 } 501 502 if (guid_eq(md_entry.item_id, virtual_size_guid)) { 503 if (s->metadata_entries.present & META_VIRTUAL_DISK_SIZE_PRESENT) { 504 ret = -EINVAL; 505 goto exit; 506 } 507 s->metadata_entries.virtual_disk_size_entry = md_entry; 508 s->metadata_entries.present |= META_VIRTUAL_DISK_SIZE_PRESENT; 509 continue; 510 } 511 512 if (guid_eq(md_entry.item_id, page83_guid)) { 513 if (s->metadata_entries.present & META_PAGE_83_PRESENT) { 514 ret = -EINVAL; 515 goto exit; 516 } 517 s->metadata_entries.page83_data_entry = md_entry; 518 s->metadata_entries.present |= META_PAGE_83_PRESENT; 519 continue; 520 } 521 522 if (guid_eq(md_entry.item_id, logical_sector_guid)) { 523 if (s->metadata_entries.present & 524 META_LOGICAL_SECTOR_SIZE_PRESENT) { 525 ret = -EINVAL; 526 goto exit; 527 } 528 s->metadata_entries.logical_sector_size_entry = md_entry; 529 s->metadata_entries.present |= META_LOGICAL_SECTOR_SIZE_PRESENT; 530 continue; 531 } 532 533 if (guid_eq(md_entry.item_id, phys_sector_guid)) { 534 if (s->metadata_entries.present & META_PHYS_SECTOR_SIZE_PRESENT) { 535 ret = -EINVAL; 536 goto exit; 537 } 538 s->metadata_entries.phys_sector_size_entry = md_entry; 539 s->metadata_entries.present |= META_PHYS_SECTOR_SIZE_PRESENT; 540 continue; 541 } 542 543 if (guid_eq(md_entry.item_id, parent_locator_guid)) { 544 if (s->metadata_entries.present & META_PARENT_LOCATOR_PRESENT) { 545 ret = -EINVAL; 546 goto exit; 547 } 548 s->metadata_entries.parent_locator_entry = md_entry; 549 s->metadata_entries.present |= META_PARENT_LOCATOR_PRESENT; 550 continue; 551 } 552 553 if (md_entry.data_bits & VHDX_META_FLAGS_IS_REQUIRED) { 554 /* cannot read vhdx file - required region table entry that 555 * we do not understand. per spec, we must fail to open */ 556 ret = -ENOTSUP; 557 goto exit; 558 } 559 } 560 561 if (s->metadata_entries.present != META_ALL_PRESENT) { 562 ret = -ENOTSUP; 563 goto exit; 564 } 565 566 ret = bdrv_pread(bs->file, 567 s->metadata_entries.file_parameters_entry.offset 568 + s->metadata_rt.file_offset, 569 &s->params, 570 sizeof(s->params)); 571 572 if (ret < 0) { 573 goto exit; 574 } 575 576 le32_to_cpus(&s->params.block_size); 577 le32_to_cpus(&s->params.data_bits); 578 579 580 /* We now have the file parameters, so we can tell if this is a 581 * differencing file (i.e.. has_parent), is dynamic or fixed 582 * sized (leave_blocks_allocated), and the block size */ 583 584 /* The parent locator required iff the file parameters has_parent set */ 585 if (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) { 586 if (s->metadata_entries.present & META_PARENT_LOCATOR_PRESENT) { 587 /* TODO: parse parent locator fields */ 588 ret = -ENOTSUP; /* temp, until differencing files are supported */ 589 goto exit; 590 } else { 591 /* if has_parent is set, but there is not parent locator present, 592 * then that is an invalid combination */ 593 ret = -EINVAL; 594 goto exit; 595 } 596 } 597 598 /* determine virtual disk size, logical sector size, 599 * and phys sector size */ 600 601 ret = bdrv_pread(bs->file, 602 s->metadata_entries.virtual_disk_size_entry.offset 603 + s->metadata_rt.file_offset, 604 &s->virtual_disk_size, 605 sizeof(uint64_t)); 606 if (ret < 0) { 607 goto exit; 608 } 609 ret = bdrv_pread(bs->file, 610 s->metadata_entries.logical_sector_size_entry.offset 611 + s->metadata_rt.file_offset, 612 &s->logical_sector_size, 613 sizeof(uint32_t)); 614 if (ret < 0) { 615 goto exit; 616 } 617 ret = bdrv_pread(bs->file, 618 s->metadata_entries.phys_sector_size_entry.offset 619 + s->metadata_rt.file_offset, 620 &s->physical_sector_size, 621 sizeof(uint32_t)); 622 if (ret < 0) { 623 goto exit; 624 } 625 626 le64_to_cpus(&s->virtual_disk_size); 627 le32_to_cpus(&s->logical_sector_size); 628 le32_to_cpus(&s->physical_sector_size); 629 630 if (s->logical_sector_size == 0 || s->params.block_size == 0) { 631 ret = -EINVAL; 632 goto exit; 633 } 634 635 /* both block_size and sector_size are guaranteed powers of 2 */ 636 s->sectors_per_block = s->params.block_size / s->logical_sector_size; 637 s->chunk_ratio = (VHDX_MAX_SECTORS_PER_BLOCK) * 638 (uint64_t)s->logical_sector_size / 639 (uint64_t)s->params.block_size; 640 641 /* These values are ones we will want to use for division / multiplication 642 * later on, and they are all guaranteed (per the spec) to be powers of 2, 643 * so we can take advantage of that for shift operations during 644 * reads/writes */ 645 if (s->logical_sector_size & (s->logical_sector_size - 1)) { 646 ret = -EINVAL; 647 goto exit; 648 } 649 if (s->sectors_per_block & (s->sectors_per_block - 1)) { 650 ret = -EINVAL; 651 goto exit; 652 } 653 if (s->chunk_ratio & (s->chunk_ratio - 1)) { 654 ret = -EINVAL; 655 goto exit; 656 } 657 s->block_size = s->params.block_size; 658 if (s->block_size & (s->block_size - 1)) { 659 ret = -EINVAL; 660 goto exit; 661 } 662 663 s->logical_sector_size_bits = 31 - clz32(s->logical_sector_size); 664 s->sectors_per_block_bits = 31 - clz32(s->sectors_per_block); 665 s->chunk_ratio_bits = 63 - clz64(s->chunk_ratio); 666 s->block_size_bits = 31 - clz32(s->block_size); 667 668 ret = 0; 669 670 exit: 671 qemu_vfree(buffer); 672 return ret; 673 } 674 675 /* Parse the replay log. Per the VHDX spec, if the log is present 676 * it must be replayed prior to opening the file, even read-only. 677 * 678 * If read-only, we must replay the log in RAM (or refuse to open 679 * a dirty VHDX file read-only */ 680 static int vhdx_parse_log(BlockDriverState *bs, BDRVVHDXState *s) 681 { 682 int ret = 0; 683 int i; 684 VHDXHeader *hdr; 685 686 hdr = s->headers[s->curr_header]; 687 688 /* either the log guid, or log length is zero, 689 * then a replay log is present */ 690 for (i = 0; i < sizeof(hdr->log_guid.data4); i++) { 691 ret |= hdr->log_guid.data4[i]; 692 } 693 if (hdr->log_guid.data1 == 0 && 694 hdr->log_guid.data2 == 0 && 695 hdr->log_guid.data3 == 0 && 696 ret == 0) { 697 goto exit; 698 } 699 700 /* per spec, only log version of 0 is supported */ 701 if (hdr->log_version != 0) { 702 ret = -EINVAL; 703 goto exit; 704 } 705 706 if (hdr->log_length == 0) { 707 goto exit; 708 } 709 710 /* We currently do not support images with logs to replay */ 711 ret = -ENOTSUP; 712 713 exit: 714 return ret; 715 } 716 717 718 static int vhdx_open(BlockDriverState *bs, QDict *options, int flags) 719 { 720 BDRVVHDXState *s = bs->opaque; 721 int ret = 0; 722 uint32_t i; 723 uint64_t signature; 724 uint32_t data_blocks_cnt, bitmap_blocks_cnt; 725 726 727 s->bat = NULL; 728 729 qemu_co_mutex_init(&s->lock); 730 731 /* validate the file signature */ 732 ret = bdrv_pread(bs->file, 0, &signature, sizeof(uint64_t)); 733 if (ret < 0) { 734 goto fail; 735 } 736 if (memcmp(&signature, "vhdxfile", 8)) { 737 ret = -EINVAL; 738 goto fail; 739 } 740 741 ret = vhdx_parse_header(bs, s); 742 if (ret) { 743 goto fail; 744 } 745 746 ret = vhdx_parse_log(bs, s); 747 if (ret) { 748 goto fail; 749 } 750 751 ret = vhdx_open_region_tables(bs, s); 752 if (ret) { 753 goto fail; 754 } 755 756 ret = vhdx_parse_metadata(bs, s); 757 if (ret) { 758 goto fail; 759 } 760 s->block_size = s->params.block_size; 761 762 /* the VHDX spec dictates that virtual_disk_size is always a multiple of 763 * logical_sector_size */ 764 bs->total_sectors = s->virtual_disk_size >> s->logical_sector_size_bits; 765 766 data_blocks_cnt = s->virtual_disk_size >> s->block_size_bits; 767 if (s->virtual_disk_size - (data_blocks_cnt << s->block_size_bits)) { 768 data_blocks_cnt++; 769 } 770 bitmap_blocks_cnt = data_blocks_cnt >> s->chunk_ratio_bits; 771 if (data_blocks_cnt - (bitmap_blocks_cnt << s->chunk_ratio_bits)) { 772 bitmap_blocks_cnt++; 773 } 774 775 if (s->parent_entries) { 776 s->bat_entries = bitmap_blocks_cnt * (s->chunk_ratio + 1); 777 } else { 778 s->bat_entries = data_blocks_cnt + 779 ((data_blocks_cnt - 1) >> s->chunk_ratio_bits); 780 } 781 782 s->bat_offset = s->bat_rt.file_offset; 783 784 if (s->bat_entries > s->bat_rt.length / sizeof(VHDXBatEntry)) { 785 /* BAT allocation is not large enough for all entries */ 786 ret = -EINVAL; 787 goto fail; 788 } 789 790 s->bat = qemu_blockalign(bs, s->bat_rt.length); 791 792 ret = bdrv_pread(bs->file, s->bat_offset, s->bat, s->bat_rt.length); 793 if (ret < 0) { 794 goto fail; 795 } 796 797 for (i = 0; i < s->bat_entries; i++) { 798 le64_to_cpus(&s->bat[i]); 799 } 800 801 if (flags & BDRV_O_RDWR) { 802 ret = -ENOTSUP; 803 goto fail; 804 } 805 806 /* TODO: differencing files, write */ 807 808 return 0; 809 fail: 810 qemu_vfree(s->headers[0]); 811 qemu_vfree(s->headers[1]); 812 qemu_vfree(s->bat); 813 qemu_vfree(s->parent_entries); 814 return ret; 815 } 816 817 static int vhdx_reopen_prepare(BDRVReopenState *state, 818 BlockReopenQueue *queue, Error **errp) 819 { 820 return 0; 821 } 822 823 824 /* 825 * Perform sector to block offset translations, to get various 826 * sector and file offsets into the image. See VHDXSectorInfo 827 */ 828 static void vhdx_block_translate(BDRVVHDXState *s, int64_t sector_num, 829 int nb_sectors, VHDXSectorInfo *sinfo) 830 { 831 uint32_t block_offset; 832 833 sinfo->bat_idx = sector_num >> s->sectors_per_block_bits; 834 /* effectively a modulo - this gives us the offset into the block 835 * (in sector sizes) for our sector number */ 836 block_offset = sector_num - (sinfo->bat_idx << s->sectors_per_block_bits); 837 /* the chunk ratio gives us the interleaving of the sector 838 * bitmaps, so we need to advance our page block index by the 839 * sector bitmaps entry number */ 840 sinfo->bat_idx += sinfo->bat_idx >> s->chunk_ratio_bits; 841 842 /* the number of sectors we can read/write in this cycle */ 843 sinfo->sectors_avail = s->sectors_per_block - block_offset; 844 845 sinfo->bytes_left = sinfo->sectors_avail << s->logical_sector_size_bits; 846 847 if (sinfo->sectors_avail > nb_sectors) { 848 sinfo->sectors_avail = nb_sectors; 849 } 850 851 sinfo->bytes_avail = sinfo->sectors_avail << s->logical_sector_size_bits; 852 853 sinfo->file_offset = s->bat[sinfo->bat_idx] >> VHDX_BAT_FILE_OFF_BITS; 854 855 sinfo->block_offset = block_offset << s->logical_sector_size_bits; 856 857 /* The file offset must be past the header section, so must be > 0 */ 858 if (sinfo->file_offset == 0) { 859 return; 860 } 861 862 /* block offset is the offset in vhdx logical sectors, in 863 * the payload data block. Convert that to a byte offset 864 * in the block, and add in the payload data block offset 865 * in the file, in bytes, to get the final read address */ 866 867 sinfo->file_offset <<= 20; /* now in bytes, rather than 1MB units */ 868 sinfo->file_offset += sinfo->block_offset; 869 } 870 871 872 873 static coroutine_fn int vhdx_co_readv(BlockDriverState *bs, int64_t sector_num, 874 int nb_sectors, QEMUIOVector *qiov) 875 { 876 BDRVVHDXState *s = bs->opaque; 877 int ret = 0; 878 VHDXSectorInfo sinfo; 879 uint64_t bytes_done = 0; 880 QEMUIOVector hd_qiov; 881 882 qemu_iovec_init(&hd_qiov, qiov->niov); 883 884 qemu_co_mutex_lock(&s->lock); 885 886 while (nb_sectors > 0) { 887 /* We are a differencing file, so we need to inspect the sector bitmap 888 * to see if we have the data or not */ 889 if (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) { 890 /* not supported yet */ 891 ret = -ENOTSUP; 892 goto exit; 893 } else { 894 vhdx_block_translate(s, sector_num, nb_sectors, &sinfo); 895 896 qemu_iovec_reset(&hd_qiov); 897 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, sinfo.bytes_avail); 898 899 /* check the payload block state */ 900 switch (s->bat[sinfo.bat_idx] & VHDX_BAT_STATE_BIT_MASK) { 901 case PAYLOAD_BLOCK_NOT_PRESENT: /* fall through */ 902 case PAYLOAD_BLOCK_UNDEFINED: /* fall through */ 903 case PAYLOAD_BLOCK_UNMAPPED: /* fall through */ 904 case PAYLOAD_BLOCK_ZERO: 905 /* return zero */ 906 qemu_iovec_memset(&hd_qiov, 0, 0, sinfo.bytes_avail); 907 break; 908 case PAYLOAD_BLOCK_FULL_PRESENT: 909 qemu_co_mutex_unlock(&s->lock); 910 ret = bdrv_co_readv(bs->file, 911 sinfo.file_offset >> BDRV_SECTOR_BITS, 912 sinfo.sectors_avail, &hd_qiov); 913 qemu_co_mutex_lock(&s->lock); 914 if (ret < 0) { 915 goto exit; 916 } 917 break; 918 case PAYLOAD_BLOCK_PARTIALLY_PRESENT: 919 /* we don't yet support difference files, fall through 920 * to error */ 921 default: 922 ret = -EIO; 923 goto exit; 924 break; 925 } 926 nb_sectors -= sinfo.sectors_avail; 927 sector_num += sinfo.sectors_avail; 928 bytes_done += sinfo.bytes_avail; 929 } 930 } 931 ret = 0; 932 exit: 933 qemu_co_mutex_unlock(&s->lock); 934 qemu_iovec_destroy(&hd_qiov); 935 return ret; 936 } 937 938 939 940 static coroutine_fn int vhdx_co_writev(BlockDriverState *bs, int64_t sector_num, 941 int nb_sectors, QEMUIOVector *qiov) 942 { 943 return -ENOTSUP; 944 } 945 946 947 static void vhdx_close(BlockDriverState *bs) 948 { 949 BDRVVHDXState *s = bs->opaque; 950 qemu_vfree(s->headers[0]); 951 qemu_vfree(s->headers[1]); 952 qemu_vfree(s->bat); 953 qemu_vfree(s->parent_entries); 954 } 955 956 static BlockDriver bdrv_vhdx = { 957 .format_name = "vhdx", 958 .instance_size = sizeof(BDRVVHDXState), 959 .bdrv_probe = vhdx_probe, 960 .bdrv_open = vhdx_open, 961 .bdrv_close = vhdx_close, 962 .bdrv_reopen_prepare = vhdx_reopen_prepare, 963 .bdrv_co_readv = vhdx_co_readv, 964 .bdrv_co_writev = vhdx_co_writev, 965 }; 966 967 static void bdrv_vhdx_init(void) 968 { 969 bdrv_register(&bdrv_vhdx); 970 } 971 972 block_init(bdrv_vhdx_init); 973