1 /* 2 * Block driver for Connectix / Microsoft Virtual PC images 3 * 4 * Copyright (c) 2005 Alex Beregszaszi 5 * Copyright (c) 2009 Kevin Wolf <kwolf@suse.de> 6 * 7 * Permission is hereby granted, free of charge, to any person obtaining a copy 8 * of this software and associated documentation files (the "Software"), to deal 9 * in the Software without restriction, including without limitation the rights 10 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 11 * copies of the Software, and to permit persons to whom the Software is 12 * furnished to do so, subject to the following conditions: 13 * 14 * The above copyright notice and this permission notice shall be included in 15 * all copies or substantial portions of the Software. 16 * 17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 20 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 23 * THE SOFTWARE. 24 */ 25 #include "qemu-common.h" 26 #include "block_int.h" 27 #include "module.h" 28 #include "migration.h" 29 30 /**************************************************************/ 31 32 #define HEADER_SIZE 512 33 34 //#define CACHE 35 36 enum vhd_type { 37 VHD_FIXED = 2, 38 VHD_DYNAMIC = 3, 39 VHD_DIFFERENCING = 4, 40 }; 41 42 // Seconds since Jan 1, 2000 0:00:00 (UTC) 43 #define VHD_TIMESTAMP_BASE 946684800 44 45 // always big-endian 46 struct vhd_footer { 47 char creator[8]; // "conectix" 48 uint32_t features; 49 uint32_t version; 50 51 // Offset of next header structure, 0xFFFFFFFF if none 52 uint64_t data_offset; 53 54 // Seconds since Jan 1, 2000 0:00:00 (UTC) 55 uint32_t timestamp; 56 57 char creator_app[4]; // "vpc " 58 uint16_t major; 59 uint16_t minor; 60 char creator_os[4]; // "Wi2k" 61 62 uint64_t orig_size; 63 uint64_t size; 64 65 uint16_t cyls; 66 uint8_t heads; 67 uint8_t secs_per_cyl; 68 69 uint32_t type; 70 71 // Checksum of the Hard Disk Footer ("one's complement of the sum of all 72 // the bytes in the footer without the checksum field") 73 uint32_t checksum; 74 75 // UUID used to identify a parent hard disk (backing file) 76 uint8_t uuid[16]; 77 78 uint8_t in_saved_state; 79 }; 80 81 struct vhd_dyndisk_header { 82 char magic[8]; // "cxsparse" 83 84 // Offset of next header structure, 0xFFFFFFFF if none 85 uint64_t data_offset; 86 87 // Offset of the Block Allocation Table (BAT) 88 uint64_t table_offset; 89 90 uint32_t version; 91 uint32_t max_table_entries; // 32bit/entry 92 93 // 2 MB by default, must be a power of two 94 uint32_t block_size; 95 96 uint32_t checksum; 97 uint8_t parent_uuid[16]; 98 uint32_t parent_timestamp; 99 uint32_t reserved; 100 101 // Backing file name (in UTF-16) 102 uint8_t parent_name[512]; 103 104 struct { 105 uint32_t platform; 106 uint32_t data_space; 107 uint32_t data_length; 108 uint32_t reserved; 109 uint64_t data_offset; 110 } parent_locator[8]; 111 }; 112 113 typedef struct BDRVVPCState { 114 CoMutex lock; 115 uint8_t footer_buf[HEADER_SIZE]; 116 uint64_t free_data_block_offset; 117 int max_table_entries; 118 uint32_t *pagetable; 119 uint64_t bat_offset; 120 uint64_t last_bitmap_offset; 121 122 uint32_t block_size; 123 uint32_t bitmap_size; 124 125 #ifdef CACHE 126 uint8_t *pageentry_u8; 127 uint32_t *pageentry_u32; 128 uint16_t *pageentry_u16; 129 130 uint64_t last_bitmap; 131 #endif 132 133 Error *migration_blocker; 134 } BDRVVPCState; 135 136 static uint32_t vpc_checksum(uint8_t* buf, size_t size) 137 { 138 uint32_t res = 0; 139 int i; 140 141 for (i = 0; i < size; i++) 142 res += buf[i]; 143 144 return ~res; 145 } 146 147 148 static int vpc_probe(const uint8_t *buf, int buf_size, const char *filename) 149 { 150 if (buf_size >= 8 && !strncmp((char *)buf, "conectix", 8)) 151 return 100; 152 return 0; 153 } 154 155 static int vpc_open(BlockDriverState *bs, int flags) 156 { 157 BDRVVPCState *s = bs->opaque; 158 int i; 159 struct vhd_footer* footer; 160 struct vhd_dyndisk_header* dyndisk_header; 161 uint8_t buf[HEADER_SIZE]; 162 uint32_t checksum; 163 int err = -1; 164 165 if (bdrv_pread(bs->file, 0, s->footer_buf, HEADER_SIZE) != HEADER_SIZE) 166 goto fail; 167 168 footer = (struct vhd_footer*) s->footer_buf; 169 if (strncmp(footer->creator, "conectix", 8)) 170 goto fail; 171 172 checksum = be32_to_cpu(footer->checksum); 173 footer->checksum = 0; 174 if (vpc_checksum(s->footer_buf, HEADER_SIZE) != checksum) 175 fprintf(stderr, "block-vpc: The header checksum of '%s' is " 176 "incorrect.\n", bs->filename); 177 178 // The visible size of a image in Virtual PC depends on the geometry 179 // rather than on the size stored in the footer (the size in the footer 180 // is too large usually) 181 bs->total_sectors = (int64_t) 182 be16_to_cpu(footer->cyls) * footer->heads * footer->secs_per_cyl; 183 184 if (bs->total_sectors >= 65535 * 16 * 255) { 185 err = -EFBIG; 186 goto fail; 187 } 188 189 if (bdrv_pread(bs->file, be64_to_cpu(footer->data_offset), buf, HEADER_SIZE) 190 != HEADER_SIZE) 191 goto fail; 192 193 dyndisk_header = (struct vhd_dyndisk_header*) buf; 194 195 if (strncmp(dyndisk_header->magic, "cxsparse", 8)) 196 goto fail; 197 198 199 s->block_size = be32_to_cpu(dyndisk_header->block_size); 200 s->bitmap_size = ((s->block_size / (8 * 512)) + 511) & ~511; 201 202 s->max_table_entries = be32_to_cpu(dyndisk_header->max_table_entries); 203 s->pagetable = g_malloc(s->max_table_entries * 4); 204 205 s->bat_offset = be64_to_cpu(dyndisk_header->table_offset); 206 if (bdrv_pread(bs->file, s->bat_offset, s->pagetable, 207 s->max_table_entries * 4) != s->max_table_entries * 4) 208 goto fail; 209 210 s->free_data_block_offset = 211 (s->bat_offset + (s->max_table_entries * 4) + 511) & ~511; 212 213 for (i = 0; i < s->max_table_entries; i++) { 214 be32_to_cpus(&s->pagetable[i]); 215 if (s->pagetable[i] != 0xFFFFFFFF) { 216 int64_t next = (512 * (int64_t) s->pagetable[i]) + 217 s->bitmap_size + s->block_size; 218 219 if (next> s->free_data_block_offset) 220 s->free_data_block_offset = next; 221 } 222 } 223 224 s->last_bitmap_offset = (int64_t) -1; 225 226 #ifdef CACHE 227 s->pageentry_u8 = g_malloc(512); 228 s->pageentry_u32 = s->pageentry_u8; 229 s->pageentry_u16 = s->pageentry_u8; 230 s->last_pagetable = -1; 231 #endif 232 233 qemu_co_mutex_init(&s->lock); 234 235 /* Disable migration when VHD images are used */ 236 error_set(&s->migration_blocker, 237 QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED, 238 "vpc", bs->device_name, "live migration"); 239 migrate_add_blocker(s->migration_blocker); 240 241 return 0; 242 fail: 243 return err; 244 } 245 246 /* 247 * Returns the absolute byte offset of the given sector in the image file. 248 * If the sector is not allocated, -1 is returned instead. 249 * 250 * The parameter write must be 1 if the offset will be used for a write 251 * operation (the block bitmaps is updated then), 0 otherwise. 252 */ 253 static inline int64_t get_sector_offset(BlockDriverState *bs, 254 int64_t sector_num, int write) 255 { 256 BDRVVPCState *s = bs->opaque; 257 uint64_t offset = sector_num * 512; 258 uint64_t bitmap_offset, block_offset; 259 uint32_t pagetable_index, pageentry_index; 260 261 pagetable_index = offset / s->block_size; 262 pageentry_index = (offset % s->block_size) / 512; 263 264 if (pagetable_index >= s->max_table_entries || s->pagetable[pagetable_index] == 0xffffffff) 265 return -1; // not allocated 266 267 bitmap_offset = 512 * (uint64_t) s->pagetable[pagetable_index]; 268 block_offset = bitmap_offset + s->bitmap_size + (512 * pageentry_index); 269 270 // We must ensure that we don't write to any sectors which are marked as 271 // unused in the bitmap. We get away with setting all bits in the block 272 // bitmap each time we write to a new block. This might cause Virtual PC to 273 // miss sparse read optimization, but it's not a problem in terms of 274 // correctness. 275 if (write && (s->last_bitmap_offset != bitmap_offset)) { 276 uint8_t bitmap[s->bitmap_size]; 277 278 s->last_bitmap_offset = bitmap_offset; 279 memset(bitmap, 0xff, s->bitmap_size); 280 bdrv_pwrite_sync(bs->file, bitmap_offset, bitmap, s->bitmap_size); 281 } 282 283 // printf("sector: %" PRIx64 ", index: %x, offset: %x, bioff: %" PRIx64 ", bloff: %" PRIx64 "\n", 284 // sector_num, pagetable_index, pageentry_index, 285 // bitmap_offset, block_offset); 286 287 // disabled by reason 288 #if 0 289 #ifdef CACHE 290 if (bitmap_offset != s->last_bitmap) 291 { 292 lseek(s->fd, bitmap_offset, SEEK_SET); 293 294 s->last_bitmap = bitmap_offset; 295 296 // Scary! Bitmap is stored as big endian 32bit entries, 297 // while we used to look it up byte by byte 298 read(s->fd, s->pageentry_u8, 512); 299 for (i = 0; i < 128; i++) 300 be32_to_cpus(&s->pageentry_u32[i]); 301 } 302 303 if ((s->pageentry_u8[pageentry_index / 8] >> (pageentry_index % 8)) & 1) 304 return -1; 305 #else 306 lseek(s->fd, bitmap_offset + (pageentry_index / 8), SEEK_SET); 307 308 read(s->fd, &bitmap_entry, 1); 309 310 if ((bitmap_entry >> (pageentry_index % 8)) & 1) 311 return -1; // not allocated 312 #endif 313 #endif 314 315 return block_offset; 316 } 317 318 /* 319 * Writes the footer to the end of the image file. This is needed when the 320 * file grows as it overwrites the old footer 321 * 322 * Returns 0 on success and < 0 on error 323 */ 324 static int rewrite_footer(BlockDriverState* bs) 325 { 326 int ret; 327 BDRVVPCState *s = bs->opaque; 328 int64_t offset = s->free_data_block_offset; 329 330 ret = bdrv_pwrite_sync(bs->file, offset, s->footer_buf, HEADER_SIZE); 331 if (ret < 0) 332 return ret; 333 334 return 0; 335 } 336 337 /* 338 * Allocates a new block. This involves writing a new footer and updating 339 * the Block Allocation Table to use the space at the old end of the image 340 * file (overwriting the old footer) 341 * 342 * Returns the sectors' offset in the image file on success and < 0 on error 343 */ 344 static int64_t alloc_block(BlockDriverState* bs, int64_t sector_num) 345 { 346 BDRVVPCState *s = bs->opaque; 347 int64_t bat_offset; 348 uint32_t index, bat_value; 349 int ret; 350 uint8_t bitmap[s->bitmap_size]; 351 352 // Check if sector_num is valid 353 if ((sector_num < 0) || (sector_num > bs->total_sectors)) 354 return -1; 355 356 // Write entry into in-memory BAT 357 index = (sector_num * 512) / s->block_size; 358 if (s->pagetable[index] != 0xFFFFFFFF) 359 return -1; 360 361 s->pagetable[index] = s->free_data_block_offset / 512; 362 363 // Initialize the block's bitmap 364 memset(bitmap, 0xff, s->bitmap_size); 365 ret = bdrv_pwrite_sync(bs->file, s->free_data_block_offset, bitmap, 366 s->bitmap_size); 367 if (ret < 0) { 368 return ret; 369 } 370 371 // Write new footer (the old one will be overwritten) 372 s->free_data_block_offset += s->block_size + s->bitmap_size; 373 ret = rewrite_footer(bs); 374 if (ret < 0) 375 goto fail; 376 377 // Write BAT entry to disk 378 bat_offset = s->bat_offset + (4 * index); 379 bat_value = be32_to_cpu(s->pagetable[index]); 380 ret = bdrv_pwrite_sync(bs->file, bat_offset, &bat_value, 4); 381 if (ret < 0) 382 goto fail; 383 384 return get_sector_offset(bs, sector_num, 0); 385 386 fail: 387 s->free_data_block_offset -= (s->block_size + s->bitmap_size); 388 return -1; 389 } 390 391 static int vpc_read(BlockDriverState *bs, int64_t sector_num, 392 uint8_t *buf, int nb_sectors) 393 { 394 BDRVVPCState *s = bs->opaque; 395 int ret; 396 int64_t offset; 397 int64_t sectors, sectors_per_block; 398 399 while (nb_sectors > 0) { 400 offset = get_sector_offset(bs, sector_num, 0); 401 402 sectors_per_block = s->block_size >> BDRV_SECTOR_BITS; 403 sectors = sectors_per_block - (sector_num % sectors_per_block); 404 if (sectors > nb_sectors) { 405 sectors = nb_sectors; 406 } 407 408 if (offset == -1) { 409 memset(buf, 0, sectors * BDRV_SECTOR_SIZE); 410 } else { 411 ret = bdrv_pread(bs->file, offset, buf, 412 sectors * BDRV_SECTOR_SIZE); 413 if (ret != sectors * BDRV_SECTOR_SIZE) { 414 return -1; 415 } 416 } 417 418 nb_sectors -= sectors; 419 sector_num += sectors; 420 buf += sectors * BDRV_SECTOR_SIZE; 421 } 422 return 0; 423 } 424 425 static coroutine_fn int vpc_co_read(BlockDriverState *bs, int64_t sector_num, 426 uint8_t *buf, int nb_sectors) 427 { 428 int ret; 429 BDRVVPCState *s = bs->opaque; 430 qemu_co_mutex_lock(&s->lock); 431 ret = vpc_read(bs, sector_num, buf, nb_sectors); 432 qemu_co_mutex_unlock(&s->lock); 433 return ret; 434 } 435 436 static int vpc_write(BlockDriverState *bs, int64_t sector_num, 437 const uint8_t *buf, int nb_sectors) 438 { 439 BDRVVPCState *s = bs->opaque; 440 int64_t offset; 441 int64_t sectors, sectors_per_block; 442 int ret; 443 444 while (nb_sectors > 0) { 445 offset = get_sector_offset(bs, sector_num, 1); 446 447 sectors_per_block = s->block_size >> BDRV_SECTOR_BITS; 448 sectors = sectors_per_block - (sector_num % sectors_per_block); 449 if (sectors > nb_sectors) { 450 sectors = nb_sectors; 451 } 452 453 if (offset == -1) { 454 offset = alloc_block(bs, sector_num); 455 if (offset < 0) 456 return -1; 457 } 458 459 ret = bdrv_pwrite(bs->file, offset, buf, sectors * BDRV_SECTOR_SIZE); 460 if (ret != sectors * BDRV_SECTOR_SIZE) { 461 return -1; 462 } 463 464 nb_sectors -= sectors; 465 sector_num += sectors; 466 buf += sectors * BDRV_SECTOR_SIZE; 467 } 468 469 return 0; 470 } 471 472 static coroutine_fn int vpc_co_write(BlockDriverState *bs, int64_t sector_num, 473 const uint8_t *buf, int nb_sectors) 474 { 475 int ret; 476 BDRVVPCState *s = bs->opaque; 477 qemu_co_mutex_lock(&s->lock); 478 ret = vpc_write(bs, sector_num, buf, nb_sectors); 479 qemu_co_mutex_unlock(&s->lock); 480 return ret; 481 } 482 483 static coroutine_fn int vpc_co_flush(BlockDriverState *bs) 484 { 485 return bdrv_co_flush(bs->file); 486 } 487 488 /* 489 * Calculates the number of cylinders, heads and sectors per cylinder 490 * based on a given number of sectors. This is the algorithm described 491 * in the VHD specification. 492 * 493 * Note that the geometry doesn't always exactly match total_sectors but 494 * may round it down. 495 * 496 * Returns 0 on success, -EFBIG if the size is larger than 127 GB 497 */ 498 static int calculate_geometry(int64_t total_sectors, uint16_t* cyls, 499 uint8_t* heads, uint8_t* secs_per_cyl) 500 { 501 uint32_t cyls_times_heads; 502 503 if (total_sectors > 65535 * 16 * 255) 504 return -EFBIG; 505 506 if (total_sectors > 65535 * 16 * 63) { 507 *secs_per_cyl = 255; 508 *heads = 16; 509 cyls_times_heads = total_sectors / *secs_per_cyl; 510 } else { 511 *secs_per_cyl = 17; 512 cyls_times_heads = total_sectors / *secs_per_cyl; 513 *heads = (cyls_times_heads + 1023) / 1024; 514 515 if (*heads < 4) 516 *heads = 4; 517 518 if (cyls_times_heads >= (*heads * 1024) || *heads > 16) { 519 *secs_per_cyl = 31; 520 *heads = 16; 521 cyls_times_heads = total_sectors / *secs_per_cyl; 522 } 523 524 if (cyls_times_heads >= (*heads * 1024)) { 525 *secs_per_cyl = 63; 526 *heads = 16; 527 cyls_times_heads = total_sectors / *secs_per_cyl; 528 } 529 } 530 531 *cyls = cyls_times_heads / *heads; 532 533 return 0; 534 } 535 536 static int vpc_create(const char *filename, QEMUOptionParameter *options) 537 { 538 uint8_t buf[1024]; 539 struct vhd_footer* footer = (struct vhd_footer*) buf; 540 struct vhd_dyndisk_header* dyndisk_header = 541 (struct vhd_dyndisk_header*) buf; 542 int fd, i; 543 uint16_t cyls = 0; 544 uint8_t heads = 0; 545 uint8_t secs_per_cyl = 0; 546 size_t block_size, num_bat_entries; 547 int64_t total_sectors = 0; 548 int ret = -EIO; 549 550 // Read out options 551 total_sectors = get_option_parameter(options, BLOCK_OPT_SIZE)->value.n / 552 BDRV_SECTOR_SIZE; 553 554 // Create the file 555 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644); 556 if (fd < 0) 557 return -EIO; 558 559 /* Calculate matching total_size and geometry. Increase the number of 560 sectors requested until we get enough (or fail). */ 561 for (i = 0; total_sectors > (int64_t)cyls * heads * secs_per_cyl; i++) { 562 if (calculate_geometry(total_sectors + i, 563 &cyls, &heads, &secs_per_cyl)) { 564 ret = -EFBIG; 565 goto fail; 566 } 567 } 568 total_sectors = (int64_t) cyls * heads * secs_per_cyl; 569 570 // Prepare the Hard Disk Footer 571 memset(buf, 0, 1024); 572 573 memcpy(footer->creator, "conectix", 8); 574 // TODO Check if "qemu" creator_app is ok for VPC 575 memcpy(footer->creator_app, "qemu", 4); 576 memcpy(footer->creator_os, "Wi2k", 4); 577 578 footer->features = be32_to_cpu(0x02); 579 footer->version = be32_to_cpu(0x00010000); 580 footer->data_offset = be64_to_cpu(HEADER_SIZE); 581 footer->timestamp = be32_to_cpu(time(NULL) - VHD_TIMESTAMP_BASE); 582 583 // Version of Virtual PC 2007 584 footer->major = be16_to_cpu(0x0005); 585 footer->minor =be16_to_cpu(0x0003); 586 587 footer->orig_size = be64_to_cpu(total_sectors * 512); 588 footer->size = be64_to_cpu(total_sectors * 512); 589 590 footer->cyls = be16_to_cpu(cyls); 591 footer->heads = heads; 592 footer->secs_per_cyl = secs_per_cyl; 593 594 footer->type = be32_to_cpu(VHD_DYNAMIC); 595 596 // TODO uuid is missing 597 598 footer->checksum = be32_to_cpu(vpc_checksum(buf, HEADER_SIZE)); 599 600 // Write the footer (twice: at the beginning and at the end) 601 block_size = 0x200000; 602 num_bat_entries = (total_sectors + block_size / 512) / (block_size / 512); 603 604 if (write(fd, buf, HEADER_SIZE) != HEADER_SIZE) { 605 goto fail; 606 } 607 608 if (lseek(fd, 1536 + ((num_bat_entries * 4 + 511) & ~511), SEEK_SET) < 0) { 609 goto fail; 610 } 611 if (write(fd, buf, HEADER_SIZE) != HEADER_SIZE) { 612 goto fail; 613 } 614 615 // Write the initial BAT 616 if (lseek(fd, 3 * 512, SEEK_SET) < 0) { 617 goto fail; 618 } 619 620 memset(buf, 0xFF, 512); 621 for (i = 0; i < (num_bat_entries * 4 + 511) / 512; i++) { 622 if (write(fd, buf, 512) != 512) { 623 goto fail; 624 } 625 } 626 627 628 // Prepare the Dynamic Disk Header 629 memset(buf, 0, 1024); 630 631 memcpy(dyndisk_header->magic, "cxsparse", 8); 632 633 /* 634 * Note: The spec is actually wrong here for data_offset, it says 635 * 0xFFFFFFFF, but MS tools expect all 64 bits to be set. 636 */ 637 dyndisk_header->data_offset = be64_to_cpu(0xFFFFFFFFFFFFFFFFULL); 638 dyndisk_header->table_offset = be64_to_cpu(3 * 512); 639 dyndisk_header->version = be32_to_cpu(0x00010000); 640 dyndisk_header->block_size = be32_to_cpu(block_size); 641 dyndisk_header->max_table_entries = be32_to_cpu(num_bat_entries); 642 643 dyndisk_header->checksum = be32_to_cpu(vpc_checksum(buf, 1024)); 644 645 // Write the header 646 if (lseek(fd, 512, SEEK_SET) < 0) { 647 goto fail; 648 } 649 650 if (write(fd, buf, 1024) != 1024) { 651 goto fail; 652 } 653 ret = 0; 654 655 fail: 656 close(fd); 657 return ret; 658 } 659 660 static void vpc_close(BlockDriverState *bs) 661 { 662 BDRVVPCState *s = bs->opaque; 663 g_free(s->pagetable); 664 #ifdef CACHE 665 g_free(s->pageentry_u8); 666 #endif 667 668 migrate_del_blocker(s->migration_blocker); 669 error_free(s->migration_blocker); 670 } 671 672 static QEMUOptionParameter vpc_create_options[] = { 673 { 674 .name = BLOCK_OPT_SIZE, 675 .type = OPT_SIZE, 676 .help = "Virtual disk size" 677 }, 678 { NULL } 679 }; 680 681 static BlockDriver bdrv_vpc = { 682 .format_name = "vpc", 683 .instance_size = sizeof(BDRVVPCState), 684 685 .bdrv_probe = vpc_probe, 686 .bdrv_open = vpc_open, 687 .bdrv_close = vpc_close, 688 .bdrv_create = vpc_create, 689 690 .bdrv_read = vpc_co_read, 691 .bdrv_write = vpc_co_write, 692 .bdrv_co_flush_to_disk = vpc_co_flush, 693 694 .create_options = vpc_create_options, 695 }; 696 697 static void bdrv_vpc_init(void) 698 { 699 bdrv_register(&bdrv_vpc); 700 } 701 702 block_init(bdrv_vpc_init); 703