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/osdep.h"
26 #include "qapi/error.h"
27 #include "qemu-common.h"
28 #include "block/block_int.h"
29 #include "sysemu/block-backend.h"
30 #include "qemu/module.h"
31 #include "migration/migration.h"
32 #if defined(CONFIG_UUID)
33 #include <uuid/uuid.h>
36 /**************************************************************/
38 #define HEADER_SIZE 512
48 // Seconds since Jan 1, 2000 0:00:00 (UTC)
49 #define VHD_TIMESTAMP_BASE 946684800
51 #define VHD_CHS_MAX_C 65535LL
52 #define VHD_CHS_MAX_H 16
53 #define VHD_CHS_MAX_S 255
55 #define VHD_MAX_SECTORS (65535LL * 255 * 255)
56 #define VHD_MAX_GEOMETRY (VHD_CHS_MAX_C * VHD_CHS_MAX_H * VHD_CHS_MAX_S)
58 #define VPC_OPT_FORCE_SIZE "force_size"
61 typedef struct vhd_footer
{
62 char creator
[8]; // "conectix"
66 // Offset of next header structure, 0xFFFFFFFF if none
69 // Seconds since Jan 1, 2000 0:00:00 (UTC)
72 char creator_app
[4]; // "vpc "
75 char creator_os
[4]; // "Wi2k"
78 uint64_t current_size
;
86 // Checksum of the Hard Disk Footer ("one's complement of the sum of all
87 // the bytes in the footer without the checksum field")
90 // UUID used to identify a parent hard disk (backing file)
93 uint8_t in_saved_state
;
94 } QEMU_PACKED VHDFooter
;
96 typedef struct vhd_dyndisk_header
{
97 char magic
[8]; // "cxsparse"
99 // Offset of next header structure, 0xFFFFFFFF if none
100 uint64_t data_offset
;
102 // Offset of the Block Allocation Table (BAT)
103 uint64_t table_offset
;
106 uint32_t max_table_entries
; // 32bit/entry
108 // 2 MB by default, must be a power of two
112 uint8_t parent_uuid
[16];
113 uint32_t parent_timestamp
;
116 // Backing file name (in UTF-16)
117 uint8_t parent_name
[512];
122 uint32_t data_length
;
124 uint64_t data_offset
;
126 } QEMU_PACKED VHDDynDiskHeader
;
128 typedef struct BDRVVPCState
{
130 uint8_t footer_buf
[HEADER_SIZE
];
131 uint64_t free_data_block_offset
;
132 int max_table_entries
;
135 uint64_t last_bitmap_offset
;
138 uint32_t bitmap_size
;
143 uint8_t *pageentry_u8
;
144 uint32_t *pageentry_u32
;
145 uint16_t *pageentry_u16
;
147 uint64_t last_bitmap
;
150 Error
*migration_blocker
;
153 #define VPC_OPT_SIZE_CALC "force_size_calc"
154 static QemuOptsList vpc_runtime_opts
= {
155 .name
= "vpc-runtime-opts",
156 .head
= QTAILQ_HEAD_INITIALIZER(vpc_runtime_opts
.head
),
159 .name
= VPC_OPT_SIZE_CALC
,
160 .type
= QEMU_OPT_STRING
,
161 .help
= "Force disk size calculation to use either CHS geometry, "
162 "or use the disk current_size specified in the VHD footer. "
163 "{chs, current_size}"
165 { /* end of list */ }
169 static uint32_t vpc_checksum(uint8_t* buf
, size_t size
)
174 for (i
= 0; i
< size
; i
++)
181 static int vpc_probe(const uint8_t *buf
, int buf_size
, const char *filename
)
183 if (buf_size
>= 8 && !strncmp((char *)buf
, "conectix", 8))
188 static void vpc_parse_options(BlockDriverState
*bs
, QemuOpts
*opts
,
191 BDRVVPCState
*s
= bs
->opaque
;
192 const char *size_calc
;
194 size_calc
= qemu_opt_get(opts
, VPC_OPT_SIZE_CALC
);
197 /* no override, use autodetect only */
198 } else if (!strcmp(size_calc
, "current_size")) {
199 s
->force_use_sz
= true;
200 } else if (!strcmp(size_calc
, "chs")) {
201 s
->force_use_chs
= true;
203 error_setg(errp
, "Invalid size calculation mode: '%s'", size_calc
);
207 static int vpc_open(BlockDriverState
*bs
, QDict
*options
, int flags
,
210 BDRVVPCState
*s
= bs
->opaque
;
213 VHDDynDiskHeader
*dyndisk_header
;
214 QemuOpts
*opts
= NULL
;
215 Error
*local_err
= NULL
;
217 uint8_t buf
[HEADER_SIZE
];
219 uint64_t computed_size
;
220 uint64_t pagetable_size
;
221 int disk_type
= VHD_DYNAMIC
;
224 opts
= qemu_opts_create(&vpc_runtime_opts
, NULL
, 0, &error_abort
);
225 qemu_opts_absorb_qdict(opts
, options
, &local_err
);
227 error_propagate(errp
, local_err
);
232 vpc_parse_options(bs
, opts
, &local_err
);
234 error_propagate(errp
, local_err
);
239 ret
= bdrv_pread(bs
->file
->bs
, 0, s
->footer_buf
, HEADER_SIZE
);
244 footer
= (VHDFooter
*) s
->footer_buf
;
245 if (strncmp(footer
->creator
, "conectix", 8)) {
246 int64_t offset
= bdrv_getlength(bs
->file
->bs
);
250 } else if (offset
< HEADER_SIZE
) {
255 /* If a fixed disk, the footer is found only at the end of the file */
256 ret
= bdrv_pread(bs
->file
->bs
, offset
-HEADER_SIZE
, s
->footer_buf
,
261 if (strncmp(footer
->creator
, "conectix", 8)) {
262 error_setg(errp
, "invalid VPC image");
266 disk_type
= VHD_FIXED
;
269 checksum
= be32_to_cpu(footer
->checksum
);
270 footer
->checksum
= 0;
271 if (vpc_checksum(s
->footer_buf
, HEADER_SIZE
) != checksum
)
272 fprintf(stderr
, "block-vpc: The header checksum of '%s' is "
273 "incorrect.\n", bs
->filename
);
275 /* Write 'checksum' back to footer, or else will leave it with zero. */
276 footer
->checksum
= cpu_to_be32(checksum
);
278 // The visible size of a image in Virtual PC depends on the geometry
279 // rather than on the size stored in the footer (the size in the footer
280 // is too large usually)
281 bs
->total_sectors
= (int64_t)
282 be16_to_cpu(footer
->cyls
) * footer
->heads
* footer
->secs_per_cyl
;
284 /* Microsoft Virtual PC and Microsoft Hyper-V produce and read
285 * VHD image sizes differently. VPC will rely on CHS geometry,
286 * while Hyper-V and disk2vhd use the size specified in the footer.
288 * We use a couple of approaches to try and determine the correct method:
289 * look at the Creator App field, and look for images that have CHS
290 * geometry that is the maximum value.
292 * If the CHS geometry is the maximum CHS geometry, then we assume that
293 * the size is the footer->current_size to avoid truncation. Otherwise,
294 * we follow the table based on footer->creator_app:
296 * Known creator apps:
297 * 'vpc ' : CHS Virtual PC (uses disk geometry)
298 * 'qemu' : CHS QEMU (uses disk geometry)
299 * 'qem2' : current_size QEMU (uses current_size)
300 * 'win ' : current_size Hyper-V
301 * 'd2v ' : current_size Disk2vhd
302 * 'tap\0' : current_size XenServer
304 * The user can override the table values via drive options, however
305 * even with an override we will still use current_size for images
306 * that have CHS geometry of the maximum size.
308 use_chs
= (!!strncmp(footer
->creator_app
, "win ", 4) &&
309 !!strncmp(footer
->creator_app
, "qem2", 4) &&
310 !!strncmp(footer
->creator_app
, "d2v ", 4) &&
311 !!memcmp(footer
->creator_app
, "tap", 4)) || s
->force_use_chs
;
313 if (!use_chs
|| bs
->total_sectors
== VHD_MAX_GEOMETRY
|| s
->force_use_sz
) {
314 bs
->total_sectors
= be64_to_cpu(footer
->current_size
) /
318 /* Allow a maximum disk size of approximately 2 TB */
319 if (bs
->total_sectors
>= VHD_MAX_SECTORS
) {
324 if (disk_type
== VHD_DYNAMIC
) {
325 ret
= bdrv_pread(bs
->file
->bs
, be64_to_cpu(footer
->data_offset
), buf
,
331 dyndisk_header
= (VHDDynDiskHeader
*) buf
;
333 if (strncmp(dyndisk_header
->magic
, "cxsparse", 8)) {
338 s
->block_size
= be32_to_cpu(dyndisk_header
->block_size
);
339 if (!is_power_of_2(s
->block_size
) || s
->block_size
< BDRV_SECTOR_SIZE
) {
340 error_setg(errp
, "Invalid block size %" PRIu32
, s
->block_size
);
344 s
->bitmap_size
= ((s
->block_size
/ (8 * 512)) + 511) & ~511;
346 s
->max_table_entries
= be32_to_cpu(dyndisk_header
->max_table_entries
);
348 if ((bs
->total_sectors
* 512) / s
->block_size
> 0xffffffffU
) {
352 if (s
->max_table_entries
> (VHD_MAX_SECTORS
* 512) / s
->block_size
) {
357 computed_size
= (uint64_t) s
->max_table_entries
* s
->block_size
;
358 if (computed_size
< bs
->total_sectors
* 512) {
363 if (s
->max_table_entries
> SIZE_MAX
/ 4 ||
364 s
->max_table_entries
> (int) INT_MAX
/ 4) {
365 error_setg(errp
, "Max Table Entries too large (%" PRId32
")",
366 s
->max_table_entries
);
371 pagetable_size
= (uint64_t) s
->max_table_entries
* 4;
373 s
->pagetable
= qemu_try_blockalign(bs
->file
->bs
, pagetable_size
);
374 if (s
->pagetable
== NULL
) {
379 s
->bat_offset
= be64_to_cpu(dyndisk_header
->table_offset
);
381 ret
= bdrv_pread(bs
->file
->bs
, s
->bat_offset
, s
->pagetable
,
387 s
->free_data_block_offset
=
388 ROUND_UP(s
->bat_offset
+ pagetable_size
, 512);
390 for (i
= 0; i
< s
->max_table_entries
; i
++) {
391 be32_to_cpus(&s
->pagetable
[i
]);
392 if (s
->pagetable
[i
] != 0xFFFFFFFF) {
393 int64_t next
= (512 * (int64_t) s
->pagetable
[i
]) +
394 s
->bitmap_size
+ s
->block_size
;
396 if (next
> s
->free_data_block_offset
) {
397 s
->free_data_block_offset
= next
;
402 if (s
->free_data_block_offset
> bdrv_getlength(bs
->file
->bs
)) {
403 error_setg(errp
, "block-vpc: free_data_block_offset points after "
404 "the end of file. The image has been truncated.");
409 s
->last_bitmap_offset
= (int64_t) -1;
412 s
->pageentry_u8
= g_malloc(512);
413 s
->pageentry_u32
= s
->pageentry_u8
;
414 s
->pageentry_u16
= s
->pageentry_u8
;
415 s
->last_pagetable
= -1;
419 qemu_co_mutex_init(&s
->lock
);
421 /* Disable migration when VHD images are used */
422 error_setg(&s
->migration_blocker
, "The vpc format used by node '%s' "
423 "does not support live migration",
424 bdrv_get_device_or_node_name(bs
));
425 migrate_add_blocker(s
->migration_blocker
);
430 qemu_vfree(s
->pagetable
);
432 g_free(s
->pageentry_u8
);
437 static int vpc_reopen_prepare(BDRVReopenState
*state
,
438 BlockReopenQueue
*queue
, Error
**errp
)
444 * Returns the absolute byte offset of the given sector in the image file.
445 * If the sector is not allocated, -1 is returned instead.
447 * The parameter write must be 1 if the offset will be used for a write
448 * operation (the block bitmaps is updated then), 0 otherwise.
450 static inline int64_t get_sector_offset(BlockDriverState
*bs
,
451 int64_t sector_num
, int write
)
453 BDRVVPCState
*s
= bs
->opaque
;
454 uint64_t offset
= sector_num
* 512;
455 uint64_t bitmap_offset
, block_offset
;
456 uint32_t pagetable_index
, pageentry_index
;
458 pagetable_index
= offset
/ s
->block_size
;
459 pageentry_index
= (offset
% s
->block_size
) / 512;
461 if (pagetable_index
>= s
->max_table_entries
|| s
->pagetable
[pagetable_index
] == 0xffffffff)
462 return -1; // not allocated
464 bitmap_offset
= 512 * (uint64_t) s
->pagetable
[pagetable_index
];
465 block_offset
= bitmap_offset
+ s
->bitmap_size
+ (512 * pageentry_index
);
467 // We must ensure that we don't write to any sectors which are marked as
468 // unused in the bitmap. We get away with setting all bits in the block
469 // bitmap each time we write to a new block. This might cause Virtual PC to
470 // miss sparse read optimization, but it's not a problem in terms of
472 if (write
&& (s
->last_bitmap_offset
!= bitmap_offset
)) {
473 uint8_t bitmap
[s
->bitmap_size
];
475 s
->last_bitmap_offset
= bitmap_offset
;
476 memset(bitmap
, 0xff, s
->bitmap_size
);
477 bdrv_pwrite_sync(bs
->file
->bs
, bitmap_offset
, bitmap
, s
->bitmap_size
);
484 * Writes the footer to the end of the image file. This is needed when the
485 * file grows as it overwrites the old footer
487 * Returns 0 on success and < 0 on error
489 static int rewrite_footer(BlockDriverState
* bs
)
492 BDRVVPCState
*s
= bs
->opaque
;
493 int64_t offset
= s
->free_data_block_offset
;
495 ret
= bdrv_pwrite_sync(bs
->file
->bs
, offset
, s
->footer_buf
, HEADER_SIZE
);
503 * Allocates a new block. This involves writing a new footer and updating
504 * the Block Allocation Table to use the space at the old end of the image
505 * file (overwriting the old footer)
507 * Returns the sectors' offset in the image file on success and < 0 on error
509 static int64_t alloc_block(BlockDriverState
* bs
, int64_t sector_num
)
511 BDRVVPCState
*s
= bs
->opaque
;
513 uint32_t index
, bat_value
;
515 uint8_t bitmap
[s
->bitmap_size
];
517 // Check if sector_num is valid
518 if ((sector_num
< 0) || (sector_num
> bs
->total_sectors
))
521 // Write entry into in-memory BAT
522 index
= (sector_num
* 512) / s
->block_size
;
523 if (s
->pagetable
[index
] != 0xFFFFFFFF)
526 s
->pagetable
[index
] = s
->free_data_block_offset
/ 512;
528 // Initialize the block's bitmap
529 memset(bitmap
, 0xff, s
->bitmap_size
);
530 ret
= bdrv_pwrite_sync(bs
->file
->bs
, s
->free_data_block_offset
, bitmap
,
536 // Write new footer (the old one will be overwritten)
537 s
->free_data_block_offset
+= s
->block_size
+ s
->bitmap_size
;
538 ret
= rewrite_footer(bs
);
542 // Write BAT entry to disk
543 bat_offset
= s
->bat_offset
+ (4 * index
);
544 bat_value
= cpu_to_be32(s
->pagetable
[index
]);
545 ret
= bdrv_pwrite_sync(bs
->file
->bs
, bat_offset
, &bat_value
, 4);
549 return get_sector_offset(bs
, sector_num
, 0);
552 s
->free_data_block_offset
-= (s
->block_size
+ s
->bitmap_size
);
556 static int vpc_get_info(BlockDriverState
*bs
, BlockDriverInfo
*bdi
)
558 BDRVVPCState
*s
= (BDRVVPCState
*)bs
->opaque
;
559 VHDFooter
*footer
= (VHDFooter
*) s
->footer_buf
;
561 if (be32_to_cpu(footer
->type
) != VHD_FIXED
) {
562 bdi
->cluster_size
= s
->block_size
;
565 bdi
->unallocated_blocks_are_zero
= true;
569 static int vpc_read(BlockDriverState
*bs
, int64_t sector_num
,
570 uint8_t *buf
, int nb_sectors
)
572 BDRVVPCState
*s
= bs
->opaque
;
575 int64_t sectors
, sectors_per_block
;
576 VHDFooter
*footer
= (VHDFooter
*) s
->footer_buf
;
578 if (be32_to_cpu(footer
->type
) == VHD_FIXED
) {
579 return bdrv_read(bs
->file
->bs
, sector_num
, buf
, nb_sectors
);
581 while (nb_sectors
> 0) {
582 offset
= get_sector_offset(bs
, sector_num
, 0);
584 sectors_per_block
= s
->block_size
>> BDRV_SECTOR_BITS
;
585 sectors
= sectors_per_block
- (sector_num
% sectors_per_block
);
586 if (sectors
> nb_sectors
) {
587 sectors
= nb_sectors
;
591 memset(buf
, 0, sectors
* BDRV_SECTOR_SIZE
);
593 ret
= bdrv_pread(bs
->file
->bs
, offset
, buf
,
594 sectors
* BDRV_SECTOR_SIZE
);
595 if (ret
!= sectors
* BDRV_SECTOR_SIZE
) {
600 nb_sectors
-= sectors
;
601 sector_num
+= sectors
;
602 buf
+= sectors
* BDRV_SECTOR_SIZE
;
607 static coroutine_fn
int vpc_co_read(BlockDriverState
*bs
, int64_t sector_num
,
608 uint8_t *buf
, int nb_sectors
)
611 BDRVVPCState
*s
= bs
->opaque
;
612 qemu_co_mutex_lock(&s
->lock
);
613 ret
= vpc_read(bs
, sector_num
, buf
, nb_sectors
);
614 qemu_co_mutex_unlock(&s
->lock
);
618 static int vpc_write(BlockDriverState
*bs
, int64_t sector_num
,
619 const uint8_t *buf
, int nb_sectors
)
621 BDRVVPCState
*s
= bs
->opaque
;
623 int64_t sectors
, sectors_per_block
;
625 VHDFooter
*footer
= (VHDFooter
*) s
->footer_buf
;
627 if (be32_to_cpu(footer
->type
) == VHD_FIXED
) {
628 return bdrv_write(bs
->file
->bs
, sector_num
, buf
, nb_sectors
);
630 while (nb_sectors
> 0) {
631 offset
= get_sector_offset(bs
, sector_num
, 1);
633 sectors_per_block
= s
->block_size
>> BDRV_SECTOR_BITS
;
634 sectors
= sectors_per_block
- (sector_num
% sectors_per_block
);
635 if (sectors
> nb_sectors
) {
636 sectors
= nb_sectors
;
640 offset
= alloc_block(bs
, sector_num
);
645 ret
= bdrv_pwrite(bs
->file
->bs
, offset
, buf
,
646 sectors
* BDRV_SECTOR_SIZE
);
647 if (ret
!= sectors
* BDRV_SECTOR_SIZE
) {
651 nb_sectors
-= sectors
;
652 sector_num
+= sectors
;
653 buf
+= sectors
* BDRV_SECTOR_SIZE
;
659 static coroutine_fn
int vpc_co_write(BlockDriverState
*bs
, int64_t sector_num
,
660 const uint8_t *buf
, int nb_sectors
)
663 BDRVVPCState
*s
= bs
->opaque
;
664 qemu_co_mutex_lock(&s
->lock
);
665 ret
= vpc_write(bs
, sector_num
, buf
, nb_sectors
);
666 qemu_co_mutex_unlock(&s
->lock
);
670 static int64_t coroutine_fn
vpc_co_get_block_status(BlockDriverState
*bs
,
671 int64_t sector_num
, int nb_sectors
, int *pnum
, BlockDriverState
**file
)
673 BDRVVPCState
*s
= bs
->opaque
;
674 VHDFooter
*footer
= (VHDFooter
*) s
->footer_buf
;
675 int64_t start
, offset
;
679 if (be32_to_cpu(footer
->type
) == VHD_FIXED
) {
681 *file
= bs
->file
->bs
;
682 return BDRV_BLOCK_RAW
| BDRV_BLOCK_OFFSET_VALID
| BDRV_BLOCK_DATA
|
683 (sector_num
<< BDRV_SECTOR_BITS
);
686 offset
= get_sector_offset(bs
, sector_num
, 0);
688 allocated
= (offset
!= -1);
692 /* All sectors in a block are contiguous (without using the bitmap) */
693 n
= ROUND_UP(sector_num
+ 1, s
->block_size
/ BDRV_SECTOR_SIZE
)
695 n
= MIN(n
, nb_sectors
);
700 /* *pnum can't be greater than one block for allocated
701 * sectors since there is always a bitmap in between. */
703 *file
= bs
->file
->bs
;
704 return BDRV_BLOCK_DATA
| BDRV_BLOCK_OFFSET_VALID
| start
;
706 if (nb_sectors
== 0) {
709 offset
= get_sector_offset(bs
, sector_num
, 0);
710 } while (offset
== -1);
716 * Calculates the number of cylinders, heads and sectors per cylinder
717 * based on a given number of sectors. This is the algorithm described
718 * in the VHD specification.
720 * Note that the geometry doesn't always exactly match total_sectors but
723 * Returns 0 on success, -EFBIG if the size is larger than ~2 TB. Override
724 * the hardware EIDE and ATA-2 limit of 16 heads (max disk size of 127 GB)
725 * and instead allow up to 255 heads.
727 static int calculate_geometry(int64_t total_sectors
, uint16_t* cyls
,
728 uint8_t* heads
, uint8_t* secs_per_cyl
)
730 uint32_t cyls_times_heads
;
732 total_sectors
= MIN(total_sectors
, VHD_MAX_GEOMETRY
);
734 if (total_sectors
>= 65535LL * 16 * 63) {
737 cyls_times_heads
= total_sectors
/ *secs_per_cyl
;
740 cyls_times_heads
= total_sectors
/ *secs_per_cyl
;
741 *heads
= (cyls_times_heads
+ 1023) / 1024;
747 if (cyls_times_heads
>= (*heads
* 1024) || *heads
> 16) {
750 cyls_times_heads
= total_sectors
/ *secs_per_cyl
;
753 if (cyls_times_heads
>= (*heads
* 1024)) {
756 cyls_times_heads
= total_sectors
/ *secs_per_cyl
;
760 *cyls
= cyls_times_heads
/ *heads
;
765 static int create_dynamic_disk(BlockBackend
*blk
, uint8_t *buf
,
766 int64_t total_sectors
)
768 VHDDynDiskHeader
*dyndisk_header
=
769 (VHDDynDiskHeader
*) buf
;
770 size_t block_size
, num_bat_entries
;
775 // Write the footer (twice: at the beginning and at the end)
776 block_size
= 0x200000;
777 num_bat_entries
= (total_sectors
+ block_size
/ 512) / (block_size
/ 512);
779 ret
= blk_pwrite(blk
, offset
, buf
, HEADER_SIZE
);
784 offset
= 1536 + ((num_bat_entries
* 4 + 511) & ~511);
785 ret
= blk_pwrite(blk
, offset
, buf
, HEADER_SIZE
);
790 // Write the initial BAT
793 memset(buf
, 0xFF, 512);
794 for (i
= 0; i
< (num_bat_entries
* 4 + 511) / 512; i
++) {
795 ret
= blk_pwrite(blk
, offset
, buf
, 512);
802 // Prepare the Dynamic Disk Header
803 memset(buf
, 0, 1024);
805 memcpy(dyndisk_header
->magic
, "cxsparse", 8);
808 * Note: The spec is actually wrong here for data_offset, it says
809 * 0xFFFFFFFF, but MS tools expect all 64 bits to be set.
811 dyndisk_header
->data_offset
= cpu_to_be64(0xFFFFFFFFFFFFFFFFULL
);
812 dyndisk_header
->table_offset
= cpu_to_be64(3 * 512);
813 dyndisk_header
->version
= cpu_to_be32(0x00010000);
814 dyndisk_header
->block_size
= cpu_to_be32(block_size
);
815 dyndisk_header
->max_table_entries
= cpu_to_be32(num_bat_entries
);
817 dyndisk_header
->checksum
= cpu_to_be32(vpc_checksum(buf
, 1024));
822 ret
= blk_pwrite(blk
, offset
, buf
, 1024);
831 static int create_fixed_disk(BlockBackend
*blk
, uint8_t *buf
,
836 /* Add footer to total size */
837 total_size
+= HEADER_SIZE
;
839 ret
= blk_truncate(blk
, total_size
);
844 ret
= blk_pwrite(blk
, total_size
- HEADER_SIZE
, buf
, HEADER_SIZE
);
852 static int vpc_create(const char *filename
, QemuOpts
*opts
, Error
**errp
)
855 VHDFooter
*footer
= (VHDFooter
*) buf
;
856 char *disk_type_param
;
860 uint8_t secs_per_cyl
= 0;
861 int64_t total_sectors
;
866 Error
*local_err
= NULL
;
867 BlockBackend
*blk
= NULL
;
869 /* Read out options */
870 total_size
= ROUND_UP(qemu_opt_get_size_del(opts
, BLOCK_OPT_SIZE
, 0),
872 disk_type_param
= qemu_opt_get_del(opts
, BLOCK_OPT_SUBFMT
);
873 if (disk_type_param
) {
874 if (!strcmp(disk_type_param
, "dynamic")) {
875 disk_type
= VHD_DYNAMIC
;
876 } else if (!strcmp(disk_type_param
, "fixed")) {
877 disk_type
= VHD_FIXED
;
879 error_setg(errp
, "Invalid disk type, %s", disk_type_param
);
884 disk_type
= VHD_DYNAMIC
;
887 force_size
= qemu_opt_get_bool_del(opts
, VPC_OPT_FORCE_SIZE
, false);
889 ret
= bdrv_create_file(filename
, opts
, &local_err
);
891 error_propagate(errp
, local_err
);
895 blk
= blk_new_open(filename
, NULL
, NULL
,
896 BDRV_O_RDWR
| BDRV_O_PROTOCOL
, &local_err
);
898 error_propagate(errp
, local_err
);
903 blk_set_allow_write_beyond_eof(blk
, true);
906 * Calculate matching total_size and geometry. Increase the number of
907 * sectors requested until we get enough (or fail). This ensures that
908 * qemu-img convert doesn't truncate images, but rather rounds up.
910 * If the image size can't be represented by a spec conformant CHS geometry,
911 * we set the geometry to 65535 x 16 x 255 (CxHxS) sectors and use
912 * the image size from the VHD footer to calculate total_sectors.
915 /* This will force the use of total_size for sector count, below */
916 cyls
= VHD_CHS_MAX_C
;
917 heads
= VHD_CHS_MAX_H
;
918 secs_per_cyl
= VHD_CHS_MAX_S
;
920 total_sectors
= MIN(VHD_MAX_GEOMETRY
, total_size
/ BDRV_SECTOR_SIZE
);
921 for (i
= 0; total_sectors
> (int64_t)cyls
* heads
* secs_per_cyl
; i
++) {
922 calculate_geometry(total_sectors
+ i
, &cyls
, &heads
, &secs_per_cyl
);
926 if ((int64_t)cyls
* heads
* secs_per_cyl
== VHD_MAX_GEOMETRY
) {
927 total_sectors
= total_size
/ BDRV_SECTOR_SIZE
;
928 /* Allow a maximum disk size of approximately 2 TB */
929 if (total_sectors
> VHD_MAX_SECTORS
) {
930 error_setg(errp
, "Disk size is too large, max size is 2040 GiB");
935 total_sectors
= (int64_t)cyls
* heads
* secs_per_cyl
;
936 total_size
= total_sectors
* BDRV_SECTOR_SIZE
;
939 /* Prepare the Hard Disk Footer */
940 memset(buf
, 0, 1024);
942 memcpy(footer
->creator
, "conectix", 8);
944 memcpy(footer
->creator_app
, "qem2", 4);
946 memcpy(footer
->creator_app
, "qemu", 4);
948 memcpy(footer
->creator_os
, "Wi2k", 4);
950 footer
->features
= cpu_to_be32(0x02);
951 footer
->version
= cpu_to_be32(0x00010000);
952 if (disk_type
== VHD_DYNAMIC
) {
953 footer
->data_offset
= cpu_to_be64(HEADER_SIZE
);
955 footer
->data_offset
= cpu_to_be64(0xFFFFFFFFFFFFFFFFULL
);
957 footer
->timestamp
= cpu_to_be32(time(NULL
) - VHD_TIMESTAMP_BASE
);
959 /* Version of Virtual PC 2007 */
960 footer
->major
= cpu_to_be16(0x0005);
961 footer
->minor
= cpu_to_be16(0x0003);
962 footer
->orig_size
= cpu_to_be64(total_size
);
963 footer
->current_size
= cpu_to_be64(total_size
);
964 footer
->cyls
= cpu_to_be16(cyls
);
965 footer
->heads
= heads
;
966 footer
->secs_per_cyl
= secs_per_cyl
;
968 footer
->type
= cpu_to_be32(disk_type
);
970 #if defined(CONFIG_UUID)
971 uuid_generate(footer
->uuid
);
974 footer
->checksum
= cpu_to_be32(vpc_checksum(buf
, HEADER_SIZE
));
976 if (disk_type
== VHD_DYNAMIC
) {
977 ret
= create_dynamic_disk(blk
, buf
, total_sectors
);
979 ret
= create_fixed_disk(blk
, buf
, total_size
);
982 error_setg(errp
, "Unable to create or write VHD header");
987 g_free(disk_type_param
);
991 static int vpc_has_zero_init(BlockDriverState
*bs
)
993 BDRVVPCState
*s
= bs
->opaque
;
994 VHDFooter
*footer
= (VHDFooter
*) s
->footer_buf
;
996 if (be32_to_cpu(footer
->type
) == VHD_FIXED
) {
997 return bdrv_has_zero_init(bs
->file
->bs
);
1003 static void vpc_close(BlockDriverState
*bs
)
1005 BDRVVPCState
*s
= bs
->opaque
;
1006 qemu_vfree(s
->pagetable
);
1008 g_free(s
->pageentry_u8
);
1011 migrate_del_blocker(s
->migration_blocker
);
1012 error_free(s
->migration_blocker
);
1015 static QemuOptsList vpc_create_opts
= {
1016 .name
= "vpc-create-opts",
1017 .head
= QTAILQ_HEAD_INITIALIZER(vpc_create_opts
.head
),
1020 .name
= BLOCK_OPT_SIZE
,
1021 .type
= QEMU_OPT_SIZE
,
1022 .help
= "Virtual disk size"
1025 .name
= BLOCK_OPT_SUBFMT
,
1026 .type
= QEMU_OPT_STRING
,
1028 "Type of virtual hard disk format. Supported formats are "
1029 "{dynamic (default) | fixed} "
1032 .name
= VPC_OPT_FORCE_SIZE
,
1033 .type
= QEMU_OPT_BOOL
,
1034 .help
= "Force disk size calculation to use the actual size "
1035 "specified, rather than using the nearest CHS-based "
1038 { /* end of list */ }
1042 static BlockDriver bdrv_vpc
= {
1043 .format_name
= "vpc",
1044 .instance_size
= sizeof(BDRVVPCState
),
1046 .bdrv_probe
= vpc_probe
,
1047 .bdrv_open
= vpc_open
,
1048 .bdrv_close
= vpc_close
,
1049 .bdrv_reopen_prepare
= vpc_reopen_prepare
,
1050 .bdrv_create
= vpc_create
,
1052 .bdrv_read
= vpc_co_read
,
1053 .bdrv_write
= vpc_co_write
,
1054 .bdrv_co_get_block_status
= vpc_co_get_block_status
,
1056 .bdrv_get_info
= vpc_get_info
,
1058 .create_opts
= &vpc_create_opts
,
1059 .bdrv_has_zero_init
= vpc_has_zero_init
,
1062 static void bdrv_vpc_init(void)
1064 bdrv_register(&bdrv_vpc
);
1067 block_init(bdrv_vpc_init
);