Merge remote-tracking branch 'remotes/huth-gitlab/tags/pull-request-2020-08-05' into...
[qemu.git] / block / bochs.c
1 /*
2 * Block driver for the various disk image formats used by Bochs
3 * Currently only for "growing" type in read-only mode
4 *
5 * Copyright (c) 2005 Alex Beregszaszi
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/osdep.h"
26 #include "qapi/error.h"
27 #include "block/block_int.h"
28 #include "qemu/module.h"
29 #include "qemu/bswap.h"
30 #include "qemu/error-report.h"
31
32 /**************************************************************/
33
34 #define HEADER_MAGIC "Bochs Virtual HD Image"
35 #define HEADER_VERSION 0x00020000
36 #define HEADER_V1 0x00010000
37 #define HEADER_SIZE 512
38
39 #define REDOLOG_TYPE "Redolog"
40 #define GROWING_TYPE "Growing"
41
42 // not allocated: 0xffffffff
43
44 // always little-endian
45 struct bochs_header {
46 char magic[32]; /* "Bochs Virtual HD Image" */
47 char type[16]; /* "Redolog" */
48 char subtype[16]; /* "Undoable" / "Volatile" / "Growing" */
49 uint32_t version;
50 uint32_t header; /* size of header */
51
52 uint32_t catalog; /* num of entries */
53 uint32_t bitmap; /* bitmap size */
54 uint32_t extent; /* extent size */
55
56 union {
57 struct {
58 uint32_t reserved; /* for ??? */
59 uint64_t disk; /* disk size */
60 char padding[HEADER_SIZE - 64 - 20 - 12];
61 } QEMU_PACKED redolog;
62 struct {
63 uint64_t disk; /* disk size */
64 char padding[HEADER_SIZE - 64 - 20 - 8];
65 } QEMU_PACKED redolog_v1;
66 char padding[HEADER_SIZE - 64 - 20];
67 } extra;
68 } QEMU_PACKED;
69
70 typedef struct BDRVBochsState {
71 CoMutex lock;
72 uint32_t *catalog_bitmap;
73 uint32_t catalog_size;
74
75 uint32_t data_offset;
76
77 uint32_t bitmap_blocks;
78 uint32_t extent_blocks;
79 uint32_t extent_size;
80 } BDRVBochsState;
81
82 static int bochs_probe(const uint8_t *buf, int buf_size, const char *filename)
83 {
84 const struct bochs_header *bochs = (const void *)buf;
85
86 if (buf_size < HEADER_SIZE)
87 return 0;
88
89 if (!strcmp(bochs->magic, HEADER_MAGIC) &&
90 !strcmp(bochs->type, REDOLOG_TYPE) &&
91 !strcmp(bochs->subtype, GROWING_TYPE) &&
92 ((le32_to_cpu(bochs->version) == HEADER_VERSION) ||
93 (le32_to_cpu(bochs->version) == HEADER_V1)))
94 return 100;
95
96 return 0;
97 }
98
99 static int bochs_open(BlockDriverState *bs, QDict *options, int flags,
100 Error **errp)
101 {
102 BDRVBochsState *s = bs->opaque;
103 uint32_t i;
104 struct bochs_header bochs;
105 int ret;
106
107 /* No write support yet */
108 ret = bdrv_apply_auto_read_only(bs, NULL, errp);
109 if (ret < 0) {
110 return ret;
111 }
112
113 bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
114 BDRV_CHILD_IMAGE, false, errp);
115 if (!bs->file) {
116 return -EINVAL;
117 }
118
119 ret = bdrv_pread(bs->file, 0, &bochs, sizeof(bochs));
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 /* Limit to 1M entries to avoid unbounded allocation. This is what is
140 * needed for the largest image that bximage can create (~8 TB). */
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_bitmap,
154 s->catalog_size * 4);
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 /* bximage actually never creates extents smaller than 4k */
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
196 fail:
197 g_free(s->catalog_bitmap);
198 return ret;
199 }
200
201 static void bochs_refresh_limits(BlockDriverState *bs, Error **errp)
202 {
203 bs->bl.request_alignment = BDRV_SECTOR_SIZE; /* No sub-sector I/O */
204 }
205
206 static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num)
207 {
208 BDRVBochsState *s = bs->opaque;
209 uint64_t offset = sector_num * 512;
210 uint64_t extent_index, extent_offset, bitmap_offset;
211 char bitmap_entry;
212 int ret;
213
214 // seek to sector
215 extent_index = offset / s->extent_size;
216 extent_offset = (offset % s->extent_size) / 512;
217
218 if (s->catalog_bitmap[extent_index] == 0xffffffff) {
219 return 0; /* not allocated */
220 }
221
222 bitmap_offset = s->data_offset +
223 (512 * (uint64_t) s->catalog_bitmap[extent_index] *
224 (s->extent_blocks + s->bitmap_blocks));
225
226 /* read in bitmap for current extent */
227 ret = bdrv_pread(bs->file, bitmap_offset + (extent_offset / 8),
228 &bitmap_entry, 1);
229 if (ret < 0) {
230 return ret;
231 }
232
233 if (!((bitmap_entry >> (extent_offset % 8)) & 1)) {
234 return 0; /* not allocated */
235 }
236
237 return bitmap_offset + (512 * (s->bitmap_blocks + extent_offset));
238 }
239
240 static int coroutine_fn
241 bochs_co_preadv(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
242 QEMUIOVector *qiov, int flags)
243 {
244 BDRVBochsState *s = bs->opaque;
245 uint64_t sector_num = offset >> BDRV_SECTOR_BITS;
246 int nb_sectors = bytes >> BDRV_SECTOR_BITS;
247 uint64_t bytes_done = 0;
248 QEMUIOVector local_qiov;
249 int ret;
250
251 assert(QEMU_IS_ALIGNED(offset, BDRV_SECTOR_SIZE));
252 assert(QEMU_IS_ALIGNED(bytes, BDRV_SECTOR_SIZE));
253
254 qemu_iovec_init(&local_qiov, qiov->niov);
255 qemu_co_mutex_lock(&s->lock);
256
257 while (nb_sectors > 0) {
258 int64_t block_offset = seek_to_sector(bs, sector_num);
259 if (block_offset < 0) {
260 ret = block_offset;
261 goto fail;
262 }
263
264 qemu_iovec_reset(&local_qiov);
265 qemu_iovec_concat(&local_qiov, qiov, bytes_done, 512);
266
267 if (block_offset > 0) {
268 ret = bdrv_co_preadv(bs->file, block_offset, 512,
269 &local_qiov, 0);
270 if (ret < 0) {
271 goto fail;
272 }
273 } else {
274 qemu_iovec_memset(&local_qiov, 0, 0, 512);
275 }
276 nb_sectors--;
277 sector_num++;
278 bytes_done += 512;
279 }
280
281 ret = 0;
282 fail:
283 qemu_co_mutex_unlock(&s->lock);
284 qemu_iovec_destroy(&local_qiov);
285
286 return ret;
287 }
288
289 static void bochs_close(BlockDriverState *bs)
290 {
291 BDRVBochsState *s = bs->opaque;
292 g_free(s->catalog_bitmap);
293 }
294
295 static BlockDriver bdrv_bochs = {
296 .format_name = "bochs",
297 .instance_size = sizeof(BDRVBochsState),
298 .bdrv_probe = bochs_probe,
299 .bdrv_open = bochs_open,
300 .bdrv_child_perm = bdrv_default_perms,
301 .bdrv_refresh_limits = bochs_refresh_limits,
302 .bdrv_co_preadv = bochs_co_preadv,
303 .bdrv_close = bochs_close,
304 .is_format = true,
305 };
306
307 static void bdrv_bochs_init(void)
308 {
309 bdrv_register(&bdrv_bochs);
310 }
311
312 block_init(bdrv_bochs_init);