1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
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"
32
33
34
35#define HEADER_MAGIC "Bochs Virtual HD Image"
36#define HEADER_VERSION 0x00020000
37#define HEADER_V1 0x00010000
38#define HEADER_SIZE 512
39
40#define REDOLOG_TYPE "Redolog"
41#define GROWING_TYPE "Growing"
42
43
44
45
46struct bochs_header {
47 char magic[32];
48 char type[16];
49 char subtype[16];
50 uint32_t version;
51 uint32_t header;
52
53 uint32_t catalog;
54 uint32_t bitmap;
55 uint32_t extent;
56
57 union {
58 struct {
59 uint32_t reserved;
60 uint64_t disk;
61 char padding[HEADER_SIZE - 64 - 20 - 12];
62 } QEMU_PACKED redolog;
63 struct {
64 uint64_t disk;
65 char padding[HEADER_SIZE - 64 - 20 - 8];
66 } QEMU_PACKED redolog_v1;
67 char padding[HEADER_SIZE - 64 - 20];
68 } extra;
69} QEMU_PACKED;
70
71typedef struct BDRVBochsState {
72 CoMutex lock;
73 uint32_t *catalog_bitmap;
74 uint32_t catalog_size;
75
76 uint32_t data_offset;
77
78 uint32_t bitmap_blocks;
79 uint32_t extent_blocks;
80 uint32_t extent_size;
81} BDRVBochsState;
82
83static int bochs_probe(const uint8_t *buf, int buf_size, const char *filename)
84{
85 const struct bochs_header *bochs = (const void *)buf;
86
87 if (buf_size < HEADER_SIZE)
88 return 0;
89
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)))
95 return 100;
96
97 return 0;
98}
99
100static int bochs_open(BlockDriverState *bs, QDict *options, int flags,
101 Error **errp)
102{
103 BDRVBochsState *s = bs->opaque;
104 uint32_t i;
105 struct bochs_header bochs;
106 int ret;
107
108
109 ret = bdrv_apply_auto_read_only(bs, NULL, errp);
110 if (ret < 0) {
111 return ret;
112 }
113
114 ret = bdrv_open_file_child(NULL, options, "file", bs, errp);
115 if (ret < 0) {
116 return ret;
117 }
118
119 ret = bdrv_pread(bs->file, 0, sizeof(bochs), &bochs, 0);
120 if (ret < 0) {
121 return ret;
122 }
123
124 if (strcmp(bochs.magic, HEADER_MAGIC) ||
125 strcmp(bochs.type, REDOLOG_TYPE) ||
126 strcmp(bochs.subtype, GROWING_TYPE) ||
127 ((le32_to_cpu(bochs.version) != HEADER_VERSION) &&
128 (le32_to_cpu(bochs.version) != HEADER_V1))) {
129 error_setg(errp, "Image not in Bochs format");
130 return -EINVAL;
131 }
132
133 if (le32_to_cpu(bochs.version) == HEADER_V1) {
134 bs->total_sectors = le64_to_cpu(bochs.extra.redolog_v1.disk) / 512;
135 } else {
136 bs->total_sectors = le64_to_cpu(bochs.extra.redolog.disk) / 512;
137 }
138
139
140
141 s->catalog_size = le32_to_cpu(bochs.catalog);
142 if (s->catalog_size > 0x100000) {
143 error_setg(errp, "Catalog size is too large");
144 return -EFBIG;
145 }
146
147 s->catalog_bitmap = g_try_new(uint32_t, s->catalog_size);
148 if (s->catalog_size && s->catalog_bitmap == NULL) {
149 error_setg(errp, "Could not allocate memory for catalog");
150 return -ENOMEM;
151 }
152
153 ret = bdrv_pread(bs->file, le32_to_cpu(bochs.header), s->catalog_size * 4,
154 s->catalog_bitmap, 0);
155 if (ret < 0) {
156 goto fail;
157 }
158
159 for (i = 0; i < s->catalog_size; i++)
160 le32_to_cpus(&s->catalog_bitmap[i]);
161
162 s->data_offset = le32_to_cpu(bochs.header) + (s->catalog_size * 4);
163
164 s->bitmap_blocks = 1 + (le32_to_cpu(bochs.bitmap) - 1) / 512;
165 s->extent_blocks = 1 + (le32_to_cpu(bochs.extent) - 1) / 512;
166
167 s->extent_size = le32_to_cpu(bochs.extent);
168 if (s->extent_size < BDRV_SECTOR_SIZE) {
169
170 error_setg(errp, "Extent size must be at least 512");
171 ret = -EINVAL;
172 goto fail;
173 } else if (!is_power_of_2(s->extent_size)) {
174 error_setg(errp, "Extent size %" PRIu32 " is not a power of two",
175 s->extent_size);
176 ret = -EINVAL;
177 goto fail;
178 } else if (s->extent_size > 0x800000) {
179 error_setg(errp, "Extent size %" PRIu32 " is too large",
180 s->extent_size);
181 ret = -EINVAL;
182 goto fail;
183 }
184
185 if (s->catalog_size < DIV_ROUND_UP(bs->total_sectors,
186 s->extent_size / BDRV_SECTOR_SIZE))
187 {
188 error_setg(errp, "Catalog size is too small for this disk size");
189 ret = -EINVAL;
190 goto fail;
191 }
192
193 qemu_co_mutex_init(&s->lock);
194 return 0;
195
196fail:
197 g_free(s->catalog_bitmap);
198 return ret;
199}
200
201static void bochs_refresh_limits(BlockDriverState *bs, Error **errp)
202{
203 bs->bl.request_alignment = BDRV_SECTOR_SIZE;
204}
205
206static int64_t coroutine_fn GRAPH_RDLOCK
207seek_to_sector(BlockDriverState *bs, int64_t sector_num)
208{
209 BDRVBochsState *s = bs->opaque;
210 uint64_t offset = sector_num * 512;
211 uint64_t extent_index, extent_offset, bitmap_offset;
212 char bitmap_entry;
213 int ret;
214
215
216 extent_index = offset / s->extent_size;
217 extent_offset = (offset % s->extent_size) / 512;
218
219 if (s->catalog_bitmap[extent_index] == 0xffffffff) {
220 return 0;
221 }
222
223 bitmap_offset = s->data_offset +
224 (512 * (uint64_t) s->catalog_bitmap[extent_index] *
225 (s->extent_blocks + s->bitmap_blocks));
226
227
228 ret = bdrv_co_pread(bs->file, bitmap_offset + (extent_offset / 8), 1,
229 &bitmap_entry, 0);
230 if (ret < 0) {
231 return ret;
232 }
233
234 if (!((bitmap_entry >> (extent_offset % 8)) & 1)) {
235 return 0;
236 }
237
238 return bitmap_offset + (512 * (s->bitmap_blocks + extent_offset));
239}
240
241static int coroutine_fn GRAPH_RDLOCK
242bochs_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
243 QEMUIOVector *qiov, BdrvRequestFlags flags)
244{
245 BDRVBochsState *s = bs->opaque;
246 uint64_t sector_num = offset >> BDRV_SECTOR_BITS;
247 int nb_sectors = bytes >> BDRV_SECTOR_BITS;
248 uint64_t bytes_done = 0;
249 QEMUIOVector local_qiov;
250 int ret;
251
252 assert(QEMU_IS_ALIGNED(offset, BDRV_SECTOR_SIZE));
253 assert(QEMU_IS_ALIGNED(bytes, BDRV_SECTOR_SIZE));
254
255 qemu_iovec_init(&local_qiov, qiov->niov);
256 qemu_co_mutex_lock(&s->lock);
257
258 while (nb_sectors > 0) {
259 int64_t block_offset = seek_to_sector(bs, sector_num);
260 if (block_offset < 0) {
261 ret = block_offset;
262 goto fail;
263 }
264
265 qemu_iovec_reset(&local_qiov);
266 qemu_iovec_concat(&local_qiov, qiov, bytes_done, 512);
267
268 if (block_offset > 0) {
269 ret = bdrv_co_preadv(bs->file, block_offset, 512,
270 &local_qiov, 0);
271 if (ret < 0) {
272 goto fail;
273 }
274 } else {
275 qemu_iovec_memset(&local_qiov, 0, 0, 512);
276 }
277 nb_sectors--;
278 sector_num++;
279 bytes_done += 512;
280 }
281
282 ret = 0;
283fail:
284 qemu_co_mutex_unlock(&s->lock);
285 qemu_iovec_destroy(&local_qiov);
286
287 return ret;
288}
289
290static void bochs_close(BlockDriverState *bs)
291{
292 BDRVBochsState *s = bs->opaque;
293 g_free(s->catalog_bitmap);
294}
295
296static BlockDriver bdrv_bochs = {
297 .format_name = "bochs",
298 .instance_size = sizeof(BDRVBochsState),
299 .bdrv_probe = bochs_probe,
300 .bdrv_open = bochs_open,
301 .bdrv_child_perm = bdrv_default_perms,
302 .bdrv_refresh_limits = bochs_refresh_limits,
303 .bdrv_co_preadv = bochs_co_preadv,
304 .bdrv_close = bochs_close,
305 .is_format = true,
306};
307
308static void bdrv_bochs_init(void)
309{
310 bdrv_register(&bdrv_bochs);
311}
312
313block_init(bdrv_bochs_init);
314