2 * Block driver for Connectix / Microsoft Virtual PC images
4 * Copyright (c) 2005 Alex Beregszaszi
5 * Copyright (c) 2009 Kevin Wolf <kwolf@suse.de>
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:
14 * The above copyright notice and this permission notice shall be included in
15 * all copies or substantial portions of the Software.
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
25 #include "qemu-common.h"
26 #include "block/block_int.h"
27 #include "qemu/module.h"
28 #include "migration/migration.h"
29 #if defined(CONFIG_UUID)
30 #include <uuid/uuid.h>
33 /**************************************************************/
35 #define HEADER_SIZE 512
45 // Seconds since Jan 1, 2000 0:00:00 (UTC)
46 #define VHD_TIMESTAMP_BASE 946684800
48 #define VHD_MAX_SECTORS (65535LL * 255 * 255)
49 #define VHD_MAX_GEOMETRY (65535LL * 16 * 255)
52 typedef struct vhd_footer {
53 char creator[8]; // "conectix"
57 // Offset of next header structure, 0xFFFFFFFF if none
60 // Seconds since Jan 1, 2000 0:00:00 (UTC)
63 char creator_app[4]; // "vpc "
66 char creator_os[4]; // "Wi2k"
69 uint64_t current_size;
77 // Checksum of the Hard Disk Footer ("one's complement of the sum of all
78 // the bytes in the footer without the checksum field")
81 // UUID used to identify a parent hard disk (backing file)
84 uint8_t in_saved_state;
85 } QEMU_PACKED VHDFooter;
87 typedef struct vhd_dyndisk_header {
88 char magic[8]; // "cxsparse"
90 // Offset of next header structure, 0xFFFFFFFF if none
93 // Offset of the Block Allocation Table (BAT)
94 uint64_t table_offset;
97 uint32_t max_table_entries; // 32bit/entry
99 // 2 MB by default, must be a power of two
103 uint8_t parent_uuid[16];
104 uint32_t parent_timestamp;
107 // Backing file name (in UTF-16)
108 uint8_t parent_name[512];
113 uint32_t data_length;
115 uint64_t data_offset;
117 } QEMU_PACKED VHDDynDiskHeader;
119 typedef struct BDRVVPCState {
121 uint8_t footer_buf[HEADER_SIZE];
122 uint64_t free_data_block_offset;
123 int max_table_entries;
126 uint64_t last_bitmap_offset;
129 uint32_t bitmap_size;
132 uint8_t *pageentry_u8;
133 uint32_t *pageentry_u32;
134 uint16_t *pageentry_u16;
136 uint64_t last_bitmap;
139 Error *migration_blocker;
142 static uint32_t vpc_checksum(uint8_t* buf, size_t size)
147 for (i = 0; i < size; i++)
154 static int vpc_probe(const uint8_t *buf, int buf_size, const char *filename)
156 if (buf_size >= 8 && !strncmp((char *)buf, "conectix", 8))
161 static int vpc_open(BlockDriverState *bs, QDict *options, int flags,
164 BDRVVPCState *s = bs->opaque;
167 VHDDynDiskHeader *dyndisk_header;
168 uint8_t buf[HEADER_SIZE];
170 uint64_t computed_size;
171 uint64_t pagetable_size;
172 int disk_type = VHD_DYNAMIC;
175 ret = bdrv_pread(bs->file, 0, s->footer_buf, HEADER_SIZE);
180 footer = (VHDFooter *) s->footer_buf;
181 if (strncmp(footer->creator, "conectix", 8)) {
182 int64_t offset = bdrv_getlength(bs->file);
186 } else if (offset < HEADER_SIZE) {
191 /* If a fixed disk, the footer is found only at the end of the file */
192 ret = bdrv_pread(bs->file, offset-HEADER_SIZE, s->footer_buf,
197 if (strncmp(footer->creator, "conectix", 8)) {
198 error_setg(errp, "invalid VPC image");
202 disk_type = VHD_FIXED;
205 checksum = be32_to_cpu(footer->checksum);
206 footer->checksum = 0;
207 if (vpc_checksum(s->footer_buf, HEADER_SIZE) != checksum)
208 fprintf(stderr, "block-vpc: The header checksum of '%s' is "
209 "incorrect.\n", bs->filename);
211 /* Write 'checksum' back to footer, or else will leave it with zero. */
212 footer->checksum = cpu_to_be32(checksum);
214 // The visible size of a image in Virtual PC depends on the geometry
215 // rather than on the size stored in the footer (the size in the footer
216 // is too large usually)
217 bs->total_sectors = (int64_t)
218 be16_to_cpu(footer->cyls) * footer->heads * footer->secs_per_cyl;
220 /* Images that have exactly the maximum geometry are probably bigger and
221 * would be truncated if we adhered to the geometry for them. Rely on
222 * footer->current_size for them. */
223 if (bs->total_sectors == VHD_MAX_GEOMETRY) {
224 bs->total_sectors = be64_to_cpu(footer->current_size) /
228 /* Allow a maximum disk size of approximately 2 TB */
229 if (bs->total_sectors >= VHD_MAX_SECTORS) {
234 if (disk_type == VHD_DYNAMIC) {
235 ret = bdrv_pread(bs->file, be64_to_cpu(footer->data_offset), buf,
241 dyndisk_header = (VHDDynDiskHeader *) buf;
243 if (strncmp(dyndisk_header->magic, "cxsparse", 8)) {
248 s->block_size = be32_to_cpu(dyndisk_header->block_size);
249 if (!is_power_of_2(s->block_size) || s->block_size < BDRV_SECTOR_SIZE) {
250 error_setg(errp, "Invalid block size %" PRIu32, s->block_size);
254 s->bitmap_size = ((s->block_size / (8 * 512)) + 511) & ~511;
256 s->max_table_entries = be32_to_cpu(dyndisk_header->max_table_entries);
258 if ((bs->total_sectors * 512) / s->block_size > 0xffffffffU) {
262 if (s->max_table_entries > (VHD_MAX_SECTORS * 512) / s->block_size) {
267 computed_size = (uint64_t) s->max_table_entries * s->block_size;
268 if (computed_size < bs->total_sectors * 512) {
273 if (s->max_table_entries > SIZE_MAX / 4 ||
274 s->max_table_entries > (int) INT_MAX / 4) {
275 error_setg(errp, "Max Table Entries too large (%" PRId32 ")",
276 s->max_table_entries);
281 pagetable_size = (uint64_t) s->max_table_entries * 4;
283 s->pagetable = qemu_try_blockalign(bs->file, pagetable_size);
284 if (s->pagetable == NULL) {
289 s->bat_offset = be64_to_cpu(dyndisk_header->table_offset);
291 ret = bdrv_pread(bs->file, s->bat_offset, s->pagetable, pagetable_size);
296 s->free_data_block_offset =
297 ROUND_UP(s->bat_offset + pagetable_size, 512);
299 for (i = 0; i < s->max_table_entries; i++) {
300 be32_to_cpus(&s->pagetable[i]);
301 if (s->pagetable[i] != 0xFFFFFFFF) {
302 int64_t next = (512 * (int64_t) s->pagetable[i]) +
303 s->bitmap_size + s->block_size;
305 if (next > s->free_data_block_offset) {
306 s->free_data_block_offset = next;
311 if (s->free_data_block_offset > bdrv_getlength(bs->file)) {
312 error_setg(errp, "block-vpc: free_data_block_offset points after "
313 "the end of file. The image has been truncated.");
318 s->last_bitmap_offset = (int64_t) -1;
321 s->pageentry_u8 = g_malloc(512);
322 s->pageentry_u32 = s->pageentry_u8;
323 s->pageentry_u16 = s->pageentry_u8;
324 s->last_pagetable = -1;
328 qemu_co_mutex_init(&s->lock);
330 /* Disable migration when VHD images are used */
331 error_setg(&s->migration_blocker, "The vpc format used by node '%s' "
332 "does not support live migration",
333 bdrv_get_device_or_node_name(bs));
334 migrate_add_blocker(s->migration_blocker);
339 qemu_vfree(s->pagetable);
341 g_free(s->pageentry_u8);
346 static int vpc_reopen_prepare(BDRVReopenState *state,
347 BlockReopenQueue *queue, Error **errp)
353 * Returns the absolute byte offset of the given sector in the image file.
354 * If the sector is not allocated, -1 is returned instead.
356 * The parameter write must be 1 if the offset will be used for a write
357 * operation (the block bitmaps is updated then), 0 otherwise.
359 static inline int64_t get_sector_offset(BlockDriverState *bs,
360 int64_t sector_num, int write)
362 BDRVVPCState *s = bs->opaque;
363 uint64_t offset = sector_num * 512;
364 uint64_t bitmap_offset, block_offset;
365 uint32_t pagetable_index, pageentry_index;
367 pagetable_index = offset / s->block_size;
368 pageentry_index = (offset % s->block_size) / 512;
370 if (pagetable_index >= s->max_table_entries || s->pagetable[pagetable_index] == 0xffffffff)
371 return -1; // not allocated
373 bitmap_offset = 512 * (uint64_t) s->pagetable[pagetable_index];
374 block_offset = bitmap_offset + s->bitmap_size + (512 * pageentry_index);
376 // We must ensure that we don't write to any sectors which are marked as
377 // unused in the bitmap. We get away with setting all bits in the block
378 // bitmap each time we write to a new block. This might cause Virtual PC to
379 // miss sparse read optimization, but it's not a problem in terms of
381 if (write && (s->last_bitmap_offset != bitmap_offset)) {
382 uint8_t bitmap[s->bitmap_size];
384 s->last_bitmap_offset = bitmap_offset;
385 memset(bitmap, 0xff, s->bitmap_size);
386 bdrv_pwrite_sync(bs->file, bitmap_offset, bitmap, s->bitmap_size);
393 * Writes the footer to the end of the image file. This is needed when the
394 * file grows as it overwrites the old footer
396 * Returns 0 on success and < 0 on error
398 static int rewrite_footer(BlockDriverState* bs)
401 BDRVVPCState *s = bs->opaque;
402 int64_t offset = s->free_data_block_offset;
404 ret = bdrv_pwrite_sync(bs->file, offset, s->footer_buf, HEADER_SIZE);
412 * Allocates a new block. This involves writing a new footer and updating
413 * the Block Allocation Table to use the space at the old end of the image
414 * file (overwriting the old footer)
416 * Returns the sectors' offset in the image file on success and < 0 on error
418 static int64_t alloc_block(BlockDriverState* bs, int64_t sector_num)
420 BDRVVPCState *s = bs->opaque;
422 uint32_t index, bat_value;
424 uint8_t bitmap[s->bitmap_size];
426 // Check if sector_num is valid
427 if ((sector_num < 0) || (sector_num > bs->total_sectors))
430 // Write entry into in-memory BAT
431 index = (sector_num * 512) / s->block_size;
432 if (s->pagetable[index] != 0xFFFFFFFF)
435 s->pagetable[index] = s->free_data_block_offset / 512;
437 // Initialize the block's bitmap
438 memset(bitmap, 0xff, s->bitmap_size);
439 ret = bdrv_pwrite_sync(bs->file, s->free_data_block_offset, bitmap,
445 // Write new footer (the old one will be overwritten)
446 s->free_data_block_offset += s->block_size + s->bitmap_size;
447 ret = rewrite_footer(bs);
451 // Write BAT entry to disk
452 bat_offset = s->bat_offset + (4 * index);
453 bat_value = cpu_to_be32(s->pagetable[index]);
454 ret = bdrv_pwrite_sync(bs->file, bat_offset, &bat_value, 4);
458 return get_sector_offset(bs, sector_num, 0);
461 s->free_data_block_offset -= (s->block_size + s->bitmap_size);
465 static int vpc_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
467 BDRVVPCState *s = (BDRVVPCState *)bs->opaque;
468 VHDFooter *footer = (VHDFooter *) s->footer_buf;
470 if (be32_to_cpu(footer->type) != VHD_FIXED) {
471 bdi->cluster_size = s->block_size;
474 bdi->unallocated_blocks_are_zero = true;
478 static int vpc_read(BlockDriverState *bs, int64_t sector_num,
479 uint8_t *buf, int nb_sectors)
481 BDRVVPCState *s = bs->opaque;
484 int64_t sectors, sectors_per_block;
485 VHDFooter *footer = (VHDFooter *) s->footer_buf;
487 if (be32_to_cpu(footer->type) == VHD_FIXED) {
488 return bdrv_read(bs->file, sector_num, buf, nb_sectors);
490 while (nb_sectors > 0) {
491 offset = get_sector_offset(bs, sector_num, 0);
493 sectors_per_block = s->block_size >> BDRV_SECTOR_BITS;
494 sectors = sectors_per_block - (sector_num % sectors_per_block);
495 if (sectors > nb_sectors) {
496 sectors = nb_sectors;
500 memset(buf, 0, sectors * BDRV_SECTOR_SIZE);
502 ret = bdrv_pread(bs->file, offset, buf,
503 sectors * BDRV_SECTOR_SIZE);
504 if (ret != sectors * BDRV_SECTOR_SIZE) {
509 nb_sectors -= sectors;
510 sector_num += sectors;
511 buf += sectors * BDRV_SECTOR_SIZE;
516 static coroutine_fn int vpc_co_read(BlockDriverState *bs, int64_t sector_num,
517 uint8_t *buf, int nb_sectors)
520 BDRVVPCState *s = bs->opaque;
521 qemu_co_mutex_lock(&s->lock);
522 ret = vpc_read(bs, sector_num, buf, nb_sectors);
523 qemu_co_mutex_unlock(&s->lock);
527 static int vpc_write(BlockDriverState *bs, int64_t sector_num,
528 const uint8_t *buf, int nb_sectors)
530 BDRVVPCState *s = bs->opaque;
532 int64_t sectors, sectors_per_block;
534 VHDFooter *footer = (VHDFooter *) s->footer_buf;
536 if (be32_to_cpu(footer->type) == VHD_FIXED) {
537 return bdrv_write(bs->file, sector_num, buf, nb_sectors);
539 while (nb_sectors > 0) {
540 offset = get_sector_offset(bs, sector_num, 1);
542 sectors_per_block = s->block_size >> BDRV_SECTOR_BITS;
543 sectors = sectors_per_block - (sector_num % sectors_per_block);
544 if (sectors > nb_sectors) {
545 sectors = nb_sectors;
549 offset = alloc_block(bs, sector_num);
554 ret = bdrv_pwrite(bs->file, offset, buf, sectors * BDRV_SECTOR_SIZE);
555 if (ret != sectors * BDRV_SECTOR_SIZE) {
559 nb_sectors -= sectors;
560 sector_num += sectors;
561 buf += sectors * BDRV_SECTOR_SIZE;
567 static coroutine_fn int vpc_co_write(BlockDriverState *bs, int64_t sector_num,
568 const uint8_t *buf, int nb_sectors)
571 BDRVVPCState *s = bs->opaque;
572 qemu_co_mutex_lock(&s->lock);
573 ret = vpc_write(bs, sector_num, buf, nb_sectors);
574 qemu_co_mutex_unlock(&s->lock);
578 static int64_t coroutine_fn vpc_co_get_block_status(BlockDriverState *bs,
579 int64_t sector_num, int nb_sectors, int *pnum)
581 BDRVVPCState *s = bs->opaque;
582 VHDFooter *footer = (VHDFooter*) s->footer_buf;
583 int64_t start, offset;
587 if (be32_to_cpu(footer->type) == VHD_FIXED) {
589 return BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID | BDRV_BLOCK_DATA |
590 (sector_num << BDRV_SECTOR_BITS);
593 offset = get_sector_offset(bs, sector_num, 0);
595 allocated = (offset != -1);
599 /* All sectors in a block are contiguous (without using the bitmap) */
600 n = ROUND_UP(sector_num + 1, s->block_size / BDRV_SECTOR_SIZE)
602 n = MIN(n, nb_sectors);
607 /* *pnum can't be greater than one block for allocated
608 * sectors since there is always a bitmap in between. */
610 return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | start;
612 if (nb_sectors == 0) {
615 offset = get_sector_offset(bs, sector_num, 0);
616 } while (offset == -1);
622 * Calculates the number of cylinders, heads and sectors per cylinder
623 * based on a given number of sectors. This is the algorithm described
624 * in the VHD specification.
626 * Note that the geometry doesn't always exactly match total_sectors but
629 * Returns 0 on success, -EFBIG if the size is larger than ~2 TB. Override
630 * the hardware EIDE and ATA-2 limit of 16 heads (max disk size of 127 GB)
631 * and instead allow up to 255 heads.
633 static int calculate_geometry(int64_t total_sectors, uint16_t* cyls,
634 uint8_t* heads, uint8_t* secs_per_cyl)
636 uint32_t cyls_times_heads;
638 total_sectors = MIN(total_sectors, VHD_MAX_GEOMETRY);
640 if (total_sectors >= 65535LL * 16 * 63) {
643 cyls_times_heads = total_sectors / *secs_per_cyl;
646 cyls_times_heads = total_sectors / *secs_per_cyl;
647 *heads = (cyls_times_heads + 1023) / 1024;
653 if (cyls_times_heads >= (*heads * 1024) || *heads > 16) {
656 cyls_times_heads = total_sectors / *secs_per_cyl;
659 if (cyls_times_heads >= (*heads * 1024)) {
662 cyls_times_heads = total_sectors / *secs_per_cyl;
666 *cyls = cyls_times_heads / *heads;
671 static int create_dynamic_disk(BlockDriverState *bs, uint8_t *buf,
672 int64_t total_sectors)
674 VHDDynDiskHeader *dyndisk_header =
675 (VHDDynDiskHeader *) buf;
676 size_t block_size, num_bat_entries;
681 // Write the footer (twice: at the beginning and at the end)
682 block_size = 0x200000;
683 num_bat_entries = (total_sectors + block_size / 512) / (block_size / 512);
685 ret = bdrv_pwrite_sync(bs, offset, buf, HEADER_SIZE);
690 offset = 1536 + ((num_bat_entries * 4 + 511) & ~511);
691 ret = bdrv_pwrite_sync(bs, offset, buf, HEADER_SIZE);
696 // Write the initial BAT
699 memset(buf, 0xFF, 512);
700 for (i = 0; i < (num_bat_entries * 4 + 511) / 512; i++) {
701 ret = bdrv_pwrite_sync(bs, offset, buf, 512);
708 // Prepare the Dynamic Disk Header
709 memset(buf, 0, 1024);
711 memcpy(dyndisk_header->magic, "cxsparse", 8);
714 * Note: The spec is actually wrong here for data_offset, it says
715 * 0xFFFFFFFF, but MS tools expect all 64 bits to be set.
717 dyndisk_header->data_offset = cpu_to_be64(0xFFFFFFFFFFFFFFFFULL);
718 dyndisk_header->table_offset = cpu_to_be64(3 * 512);
719 dyndisk_header->version = cpu_to_be32(0x00010000);
720 dyndisk_header->block_size = cpu_to_be32(block_size);
721 dyndisk_header->max_table_entries = cpu_to_be32(num_bat_entries);
723 dyndisk_header->checksum = cpu_to_be32(vpc_checksum(buf, 1024));
728 ret = bdrv_pwrite_sync(bs, offset, buf, 1024);
737 static int create_fixed_disk(BlockDriverState *bs, uint8_t *buf,
742 /* Add footer to total size */
743 total_size += HEADER_SIZE;
745 ret = bdrv_truncate(bs, total_size);
750 ret = bdrv_pwrite_sync(bs, total_size - HEADER_SIZE, buf, HEADER_SIZE);
758 static int vpc_create(const char *filename, QemuOpts *opts, Error **errp)
761 VHDFooter *footer = (VHDFooter *) buf;
762 char *disk_type_param;
766 uint8_t secs_per_cyl = 0;
767 int64_t total_sectors;
771 Error *local_err = NULL;
772 BlockDriverState *bs = NULL;
774 /* Read out options */
775 total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
777 disk_type_param = qemu_opt_get_del(opts, BLOCK_OPT_SUBFMT);
778 if (disk_type_param) {
779 if (!strcmp(disk_type_param, "dynamic")) {
780 disk_type = VHD_DYNAMIC;
781 } else if (!strcmp(disk_type_param, "fixed")) {
782 disk_type = VHD_FIXED;
788 disk_type = VHD_DYNAMIC;
791 ret = bdrv_create_file(filename, opts, &local_err);
793 error_propagate(errp, local_err);
796 ret = bdrv_open(&bs, filename, NULL, NULL, BDRV_O_RDWR | BDRV_O_PROTOCOL,
799 error_propagate(errp, local_err);
804 * Calculate matching total_size and geometry. Increase the number of
805 * sectors requested until we get enough (or fail). This ensures that
806 * qemu-img convert doesn't truncate images, but rather rounds up.
808 * If the image size can't be represented by a spec conform CHS geometry,
809 * we set the geometry to 65535 x 16 x 255 (CxHxS) sectors and use
810 * the image size from the VHD footer to calculate total_sectors.
812 total_sectors = MIN(VHD_MAX_GEOMETRY, total_size / BDRV_SECTOR_SIZE);
813 for (i = 0; total_sectors > (int64_t)cyls * heads * secs_per_cyl; i++) {
814 calculate_geometry(total_sectors + i, &cyls, &heads, &secs_per_cyl);
817 if ((int64_t)cyls * heads * secs_per_cyl == VHD_MAX_GEOMETRY) {
818 total_sectors = total_size / BDRV_SECTOR_SIZE;
819 /* Allow a maximum disk size of approximately 2 TB */
820 if (total_sectors > VHD_MAX_SECTORS) {
825 total_sectors = (int64_t)cyls * heads * secs_per_cyl;
826 total_size = total_sectors * BDRV_SECTOR_SIZE;
829 /* Prepare the Hard Disk Footer */
830 memset(buf, 0, 1024);
832 memcpy(footer->creator, "conectix", 8);
833 /* TODO Check if "qemu" creator_app is ok for VPC */
834 memcpy(footer->creator_app, "qemu", 4);
835 memcpy(footer->creator_os, "Wi2k", 4);
837 footer->features = cpu_to_be32(0x02);
838 footer->version = cpu_to_be32(0x00010000);
839 if (disk_type == VHD_DYNAMIC) {
840 footer->data_offset = cpu_to_be64(HEADER_SIZE);
842 footer->data_offset = cpu_to_be64(0xFFFFFFFFFFFFFFFFULL);
844 footer->timestamp = cpu_to_be32(time(NULL) - VHD_TIMESTAMP_BASE);
846 /* Version of Virtual PC 2007 */
847 footer->major = cpu_to_be16(0x0005);
848 footer->minor = cpu_to_be16(0x0003);
849 footer->orig_size = cpu_to_be64(total_size);
850 footer->current_size = cpu_to_be64(total_size);
851 footer->cyls = cpu_to_be16(cyls);
852 footer->heads = heads;
853 footer->secs_per_cyl = secs_per_cyl;
855 footer->type = cpu_to_be32(disk_type);
857 #if defined(CONFIG_UUID)
858 uuid_generate(footer->uuid);
861 footer->checksum = cpu_to_be32(vpc_checksum(buf, HEADER_SIZE));
863 if (disk_type == VHD_DYNAMIC) {
864 ret = create_dynamic_disk(bs, buf, total_sectors);
866 ret = create_fixed_disk(bs, buf, total_size);
871 g_free(disk_type_param);
875 static int vpc_has_zero_init(BlockDriverState *bs)
877 BDRVVPCState *s = bs->opaque;
878 VHDFooter *footer = (VHDFooter *) s->footer_buf;
880 if (be32_to_cpu(footer->type) == VHD_FIXED) {
881 return bdrv_has_zero_init(bs->file);
887 static void vpc_close(BlockDriverState *bs)
889 BDRVVPCState *s = bs->opaque;
890 qemu_vfree(s->pagetable);
892 g_free(s->pageentry_u8);
895 migrate_del_blocker(s->migration_blocker);
896 error_free(s->migration_blocker);
899 static QemuOptsList vpc_create_opts = {
900 .name = "vpc-create-opts",
901 .head = QTAILQ_HEAD_INITIALIZER(vpc_create_opts.head),
904 .name = BLOCK_OPT_SIZE,
905 .type = QEMU_OPT_SIZE,
906 .help = "Virtual disk size"
909 .name = BLOCK_OPT_SUBFMT,
910 .type = QEMU_OPT_STRING,
912 "Type of virtual hard disk format. Supported formats are "
913 "{dynamic (default) | fixed} "
915 { /* end of list */ }
919 static BlockDriver bdrv_vpc = {
920 .format_name = "vpc",
921 .instance_size = sizeof(BDRVVPCState),
923 .bdrv_probe = vpc_probe,
924 .bdrv_open = vpc_open,
925 .bdrv_close = vpc_close,
926 .bdrv_reopen_prepare = vpc_reopen_prepare,
927 .bdrv_create = vpc_create,
929 .bdrv_read = vpc_co_read,
930 .bdrv_write = vpc_co_write,
931 .bdrv_co_get_block_status = vpc_co_get_block_status,
933 .bdrv_get_info = vpc_get_info,
935 .create_opts = &vpc_create_opts,
936 .bdrv_has_zero_init = vpc_has_zero_init,
939 static void bdrv_vpc_init(void)
941 bdrv_register(&bdrv_vpc);
944 block_init(bdrv_vpc_init);