2 * Block driver for the various disk image formats used by Bochs
3 * Currently only for "growing" type in read-only mode
5 * Copyright (c) 2005 Alex Beregszaszi
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 "block/block-io.h"
28 #include "block/block_int.h"
29 #include "qemu/module.h"
30 #include "qemu/bswap.h"
31 #include "qemu/error-report.h"
33 /**************************************************************/
35 #define HEADER_MAGIC "Bochs Virtual HD Image"
36 #define HEADER_VERSION 0x00020000
37 #define HEADER_V1 0x00010000
38 #define HEADER_SIZE 512
40 #define REDOLOG_TYPE "Redolog"
41 #define GROWING_TYPE "Growing"
43 // not allocated: 0xffffffff
45 // always little-endian
47 char magic[32]; /* "Bochs Virtual HD Image" */
48 char type[16]; /* "Redolog" */
49 char subtype[16]; /* "Undoable" / "Volatile" / "Growing" */
51 uint32_t header; /* size of header */
53 uint32_t catalog; /* num of entries */
54 uint32_t bitmap; /* bitmap size */
55 uint32_t extent; /* extent size */
59 uint32_t reserved; /* for ??? */
60 uint64_t disk; /* disk size */
61 char padding[HEADER_SIZE - 64 - 20 - 12];
62 } QEMU_PACKED redolog;
64 uint64_t disk; /* disk size */
65 char padding[HEADER_SIZE - 64 - 20 - 8];
66 } QEMU_PACKED redolog_v1;
67 char padding[HEADER_SIZE - 64 - 20];
71 typedef struct BDRVBochsState {
73 uint32_t *catalog_bitmap;
74 uint32_t catalog_size;
78 uint32_t bitmap_blocks;
79 uint32_t extent_blocks;
83 static int bochs_probe(const uint8_t *buf, int buf_size, const char *filename)
85 const struct bochs_header *bochs = (const void *)buf;
87 if (buf_size < HEADER_SIZE)
90 if (!strcmp(bochs->magic, HEADER_MAGIC) &&
91 !strcmp(bochs->type, REDOLOG_TYPE) &&
92 !strcmp(bochs->subtype, GROWING_TYPE) &&
93 ((le32_to_cpu(bochs->version) == HEADER_VERSION) ||
94 (le32_to_cpu(bochs->version) == HEADER_V1)))
100 static int bochs_open(BlockDriverState *bs, QDict *options, int flags,
103 BDRVBochsState *s = bs->opaque;
105 struct bochs_header bochs;
108 /* No write support yet */
109 bdrv_graph_rdlock_main_loop();
110 ret = bdrv_apply_auto_read_only(bs, NULL, errp);
111 bdrv_graph_rdunlock_main_loop();
116 ret = bdrv_open_file_child(NULL, options, "file", bs, errp);
121 ret = bdrv_pread(bs->file, 0, sizeof(bochs), &bochs, 0);
126 if (strcmp(bochs.magic, HEADER_MAGIC) ||
127 strcmp(bochs.type, REDOLOG_TYPE) ||
128 strcmp(bochs.subtype, GROWING_TYPE) ||
129 ((le32_to_cpu(bochs.version) != HEADER_VERSION) &&
130 (le32_to_cpu(bochs.version) != HEADER_V1))) {
131 error_setg(errp, "Image not in Bochs format");
135 if (le32_to_cpu(bochs.version) == HEADER_V1) {
136 bs->total_sectors = le64_to_cpu(bochs.extra.redolog_v1.disk) / 512;
138 bs->total_sectors = le64_to_cpu(bochs.extra.redolog.disk) / 512;
141 /* Limit to 1M entries to avoid unbounded allocation. This is what is
142 * needed for the largest image that bximage can create (~8 TB). */
143 s->catalog_size = le32_to_cpu(bochs.catalog);
144 if (s->catalog_size > 0x100000) {
145 error_setg(errp, "Catalog size is too large");
149 s->catalog_bitmap = g_try_new(uint32_t, s->catalog_size);
150 if (s->catalog_size && s->catalog_bitmap == NULL) {
151 error_setg(errp, "Could not allocate memory for catalog");
155 ret = bdrv_pread(bs->file, le32_to_cpu(bochs.header), s->catalog_size * 4,
156 s->catalog_bitmap, 0);
161 for (i = 0; i < s->catalog_size; i++)
162 le32_to_cpus(&s->catalog_bitmap[i]);
164 s->data_offset = le32_to_cpu(bochs.header) + (s->catalog_size * 4);
166 s->bitmap_blocks = 1 + (le32_to_cpu(bochs.bitmap) - 1) / 512;
167 s->extent_blocks = 1 + (le32_to_cpu(bochs.extent) - 1) / 512;
169 s->extent_size = le32_to_cpu(bochs.extent);
170 if (s->extent_size < BDRV_SECTOR_SIZE) {
171 /* bximage actually never creates extents smaller than 4k */
172 error_setg(errp, "Extent size must be at least 512");
175 } else if (!is_power_of_2(s->extent_size)) {
176 error_setg(errp, "Extent size %" PRIu32 " is not a power of two",
180 } else if (s->extent_size > 0x800000) {
181 error_setg(errp, "Extent size %" PRIu32 " is too large",
187 if (s->catalog_size < DIV_ROUND_UP(bs->total_sectors,
188 s->extent_size / BDRV_SECTOR_SIZE))
190 error_setg(errp, "Catalog size is too small for this disk size");
195 qemu_co_mutex_init(&s->lock);
199 g_free(s->catalog_bitmap);
203 static void bochs_refresh_limits(BlockDriverState *bs, Error **errp)
205 bs->bl.request_alignment = BDRV_SECTOR_SIZE; /* No sub-sector I/O */
208 static int64_t coroutine_fn GRAPH_RDLOCK
209 seek_to_sector(BlockDriverState *bs, int64_t sector_num)
211 BDRVBochsState *s = bs->opaque;
212 uint64_t offset = sector_num * 512;
213 uint64_t extent_index, extent_offset, bitmap_offset;
218 extent_index = offset / s->extent_size;
219 extent_offset = (offset % s->extent_size) / 512;
221 if (s->catalog_bitmap[extent_index] == 0xffffffff) {
222 return 0; /* not allocated */
225 bitmap_offset = s->data_offset +
226 (512 * (uint64_t) s->catalog_bitmap[extent_index] *
227 (s->extent_blocks + s->bitmap_blocks));
229 /* read in bitmap for current extent */
230 ret = bdrv_co_pread(bs->file, bitmap_offset + (extent_offset / 8), 1,
236 if (!((bitmap_entry >> (extent_offset % 8)) & 1)) {
237 return 0; /* not allocated */
240 return bitmap_offset + (512 * (s->bitmap_blocks + extent_offset));
243 static int coroutine_fn GRAPH_RDLOCK
244 bochs_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
245 QEMUIOVector *qiov, BdrvRequestFlags flags)
247 BDRVBochsState *s = bs->opaque;
248 uint64_t sector_num = offset >> BDRV_SECTOR_BITS;
249 int nb_sectors = bytes >> BDRV_SECTOR_BITS;
250 uint64_t bytes_done = 0;
251 QEMUIOVector local_qiov;
254 assert(QEMU_IS_ALIGNED(offset, BDRV_SECTOR_SIZE));
255 assert(QEMU_IS_ALIGNED(bytes, BDRV_SECTOR_SIZE));
257 qemu_iovec_init(&local_qiov, qiov->niov);
258 qemu_co_mutex_lock(&s->lock);
260 while (nb_sectors > 0) {
261 int64_t block_offset = seek_to_sector(bs, sector_num);
262 if (block_offset < 0) {
267 qemu_iovec_reset(&local_qiov);
268 qemu_iovec_concat(&local_qiov, qiov, bytes_done, 512);
270 if (block_offset > 0) {
271 ret = bdrv_co_preadv(bs->file, block_offset, 512,
277 qemu_iovec_memset(&local_qiov, 0, 0, 512);
286 qemu_co_mutex_unlock(&s->lock);
287 qemu_iovec_destroy(&local_qiov);
292 static void bochs_close(BlockDriverState *bs)
294 BDRVBochsState *s = bs->opaque;
295 g_free(s->catalog_bitmap);
298 static BlockDriver bdrv_bochs = {
299 .format_name = "bochs",
300 .instance_size = sizeof(BDRVBochsState),
301 .bdrv_probe = bochs_probe,
302 .bdrv_open = bochs_open,
303 .bdrv_child_perm = bdrv_default_perms,
304 .bdrv_refresh_limits = bochs_refresh_limits,
305 .bdrv_co_preadv = bochs_co_preadv,
306 .bdrv_close = bochs_close,
310 static void bdrv_bochs_init(void)
312 bdrv_register(&bdrv_bochs);
315 block_init(bdrv_bochs_init);