xref: /qemu/block/vpc.c (revision 5ec4d682)
1019d6b8fSAnthony Liguori /*
2019d6b8fSAnthony Liguori  * Block driver for Conectix/Microsoft Virtual PC images
3019d6b8fSAnthony Liguori  *
4019d6b8fSAnthony Liguori  * Copyright (c) 2005 Alex Beregszaszi
5019d6b8fSAnthony Liguori  * Copyright (c) 2009 Kevin Wolf <kwolf@suse.de>
6019d6b8fSAnthony Liguori  *
7019d6b8fSAnthony Liguori  * Permission is hereby granted, free of charge, to any person obtaining a copy
8019d6b8fSAnthony Liguori  * of this software and associated documentation files (the "Software"), to deal
9019d6b8fSAnthony Liguori  * in the Software without restriction, including without limitation the rights
10019d6b8fSAnthony Liguori  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
11019d6b8fSAnthony Liguori  * copies of the Software, and to permit persons to whom the Software is
12019d6b8fSAnthony Liguori  * furnished to do so, subject to the following conditions:
13019d6b8fSAnthony Liguori  *
14019d6b8fSAnthony Liguori  * The above copyright notice and this permission notice shall be included in
15019d6b8fSAnthony Liguori  * all copies or substantial portions of the Software.
16019d6b8fSAnthony Liguori  *
17019d6b8fSAnthony Liguori  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18019d6b8fSAnthony Liguori  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19019d6b8fSAnthony Liguori  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
20019d6b8fSAnthony Liguori  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21019d6b8fSAnthony Liguori  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22019d6b8fSAnthony Liguori  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
23019d6b8fSAnthony Liguori  * THE SOFTWARE.
24019d6b8fSAnthony Liguori  */
25019d6b8fSAnthony Liguori #include "qemu-common.h"
26019d6b8fSAnthony Liguori #include "block_int.h"
27019d6b8fSAnthony Liguori #include "module.h"
28019d6b8fSAnthony Liguori 
29019d6b8fSAnthony Liguori /**************************************************************/
30019d6b8fSAnthony Liguori 
31019d6b8fSAnthony Liguori #define HEADER_SIZE 512
32019d6b8fSAnthony Liguori 
33019d6b8fSAnthony Liguori //#define CACHE
34019d6b8fSAnthony Liguori 
35019d6b8fSAnthony Liguori enum vhd_type {
36019d6b8fSAnthony Liguori     VHD_FIXED           = 2,
37019d6b8fSAnthony Liguori     VHD_DYNAMIC         = 3,
38019d6b8fSAnthony Liguori     VHD_DIFFERENCING    = 4,
39019d6b8fSAnthony Liguori };
40019d6b8fSAnthony Liguori 
41019d6b8fSAnthony Liguori // Seconds since Jan 1, 2000 0:00:00 (UTC)
42019d6b8fSAnthony Liguori #define VHD_TIMESTAMP_BASE 946684800
43019d6b8fSAnthony Liguori 
44019d6b8fSAnthony Liguori // always big-endian
45019d6b8fSAnthony Liguori struct vhd_footer {
46019d6b8fSAnthony Liguori     char        creator[8]; // "conectix"
47019d6b8fSAnthony Liguori     uint32_t    features;
48019d6b8fSAnthony Liguori     uint32_t    version;
49019d6b8fSAnthony Liguori 
50019d6b8fSAnthony Liguori     // Offset of next header structure, 0xFFFFFFFF if none
51019d6b8fSAnthony Liguori     uint64_t    data_offset;
52019d6b8fSAnthony Liguori 
53019d6b8fSAnthony Liguori     // Seconds since Jan 1, 2000 0:00:00 (UTC)
54019d6b8fSAnthony Liguori     uint32_t    timestamp;
55019d6b8fSAnthony Liguori 
56019d6b8fSAnthony Liguori     char        creator_app[4]; // "vpc "
57019d6b8fSAnthony Liguori     uint16_t    major;
58019d6b8fSAnthony Liguori     uint16_t    minor;
59019d6b8fSAnthony Liguori     char        creator_os[4]; // "Wi2k"
60019d6b8fSAnthony Liguori 
61019d6b8fSAnthony Liguori     uint64_t    orig_size;
62019d6b8fSAnthony Liguori     uint64_t    size;
63019d6b8fSAnthony Liguori 
64019d6b8fSAnthony Liguori     uint16_t    cyls;
65019d6b8fSAnthony Liguori     uint8_t     heads;
66019d6b8fSAnthony Liguori     uint8_t     secs_per_cyl;
67019d6b8fSAnthony Liguori 
68019d6b8fSAnthony Liguori     uint32_t    type;
69019d6b8fSAnthony Liguori 
70019d6b8fSAnthony Liguori     // Checksum of the Hard Disk Footer ("one's complement of the sum of all
71019d6b8fSAnthony Liguori     // the bytes in the footer without the checksum field")
72019d6b8fSAnthony Liguori     uint32_t    checksum;
73019d6b8fSAnthony Liguori 
74019d6b8fSAnthony Liguori     // UUID used to identify a parent hard disk (backing file)
75019d6b8fSAnthony Liguori     uint8_t     uuid[16];
76019d6b8fSAnthony Liguori 
77019d6b8fSAnthony Liguori     uint8_t     in_saved_state;
78019d6b8fSAnthony Liguori };
79019d6b8fSAnthony Liguori 
80019d6b8fSAnthony Liguori struct vhd_dyndisk_header {
81019d6b8fSAnthony Liguori     char        magic[8]; // "cxsparse"
82019d6b8fSAnthony Liguori 
83019d6b8fSAnthony Liguori     // Offset of next header structure, 0xFFFFFFFF if none
84019d6b8fSAnthony Liguori     uint64_t    data_offset;
85019d6b8fSAnthony Liguori 
86019d6b8fSAnthony Liguori     // Offset of the Block Allocation Table (BAT)
87019d6b8fSAnthony Liguori     uint64_t    table_offset;
88019d6b8fSAnthony Liguori 
89019d6b8fSAnthony Liguori     uint32_t    version;
90019d6b8fSAnthony Liguori     uint32_t    max_table_entries; // 32bit/entry
91019d6b8fSAnthony Liguori 
92019d6b8fSAnthony Liguori     // 2 MB by default, must be a power of two
93019d6b8fSAnthony Liguori     uint32_t    block_size;
94019d6b8fSAnthony Liguori 
95019d6b8fSAnthony Liguori     uint32_t    checksum;
96019d6b8fSAnthony Liguori     uint8_t     parent_uuid[16];
97019d6b8fSAnthony Liguori     uint32_t    parent_timestamp;
98019d6b8fSAnthony Liguori     uint32_t    reserved;
99019d6b8fSAnthony Liguori 
100019d6b8fSAnthony Liguori     // Backing file name (in UTF-16)
101019d6b8fSAnthony Liguori     uint8_t     parent_name[512];
102019d6b8fSAnthony Liguori 
103019d6b8fSAnthony Liguori     struct {
104019d6b8fSAnthony Liguori         uint32_t    platform;
105019d6b8fSAnthony Liguori         uint32_t    data_space;
106019d6b8fSAnthony Liguori         uint32_t    data_length;
107019d6b8fSAnthony Liguori         uint32_t    reserved;
108019d6b8fSAnthony Liguori         uint64_t    data_offset;
109019d6b8fSAnthony Liguori     } parent_locator[8];
110019d6b8fSAnthony Liguori };
111019d6b8fSAnthony Liguori 
112019d6b8fSAnthony Liguori typedef struct BDRVVPCState {
113019d6b8fSAnthony Liguori     BlockDriverState *hd;
114019d6b8fSAnthony Liguori 
115019d6b8fSAnthony Liguori     uint8_t footer_buf[HEADER_SIZE];
116019d6b8fSAnthony Liguori     uint64_t free_data_block_offset;
117019d6b8fSAnthony Liguori     int max_table_entries;
118019d6b8fSAnthony Liguori     uint32_t *pagetable;
119019d6b8fSAnthony Liguori     uint64_t bat_offset;
120019d6b8fSAnthony Liguori     uint64_t last_bitmap_offset;
121019d6b8fSAnthony Liguori 
122019d6b8fSAnthony Liguori     uint32_t block_size;
123019d6b8fSAnthony Liguori     uint32_t bitmap_size;
124019d6b8fSAnthony Liguori 
125019d6b8fSAnthony Liguori #ifdef CACHE
126019d6b8fSAnthony Liguori     uint8_t *pageentry_u8;
127019d6b8fSAnthony Liguori     uint32_t *pageentry_u32;
128019d6b8fSAnthony Liguori     uint16_t *pageentry_u16;
129019d6b8fSAnthony Liguori 
130019d6b8fSAnthony Liguori     uint64_t last_bitmap;
131019d6b8fSAnthony Liguori #endif
132019d6b8fSAnthony Liguori } BDRVVPCState;
133019d6b8fSAnthony Liguori 
134019d6b8fSAnthony Liguori static uint32_t vpc_checksum(uint8_t* buf, size_t size)
135019d6b8fSAnthony Liguori {
136019d6b8fSAnthony Liguori     uint32_t res = 0;
137019d6b8fSAnthony Liguori     int i;
138019d6b8fSAnthony Liguori 
139019d6b8fSAnthony Liguori     for (i = 0; i < size; i++)
140019d6b8fSAnthony Liguori         res += buf[i];
141019d6b8fSAnthony Liguori 
142019d6b8fSAnthony Liguori     return ~res;
143019d6b8fSAnthony Liguori }
144019d6b8fSAnthony Liguori 
145019d6b8fSAnthony Liguori 
146019d6b8fSAnthony Liguori static int vpc_probe(const uint8_t *buf, int buf_size, const char *filename)
147019d6b8fSAnthony Liguori {
148019d6b8fSAnthony Liguori     if (buf_size >= 8 && !strncmp((char *)buf, "conectix", 8))
149019d6b8fSAnthony Liguori 	return 100;
150019d6b8fSAnthony Liguori     return 0;
151019d6b8fSAnthony Liguori }
152019d6b8fSAnthony Liguori 
153019d6b8fSAnthony Liguori static int vpc_open(BlockDriverState *bs, const char *filename, int flags)
154019d6b8fSAnthony Liguori {
155019d6b8fSAnthony Liguori     BDRVVPCState *s = bs->opaque;
156019d6b8fSAnthony Liguori     int ret, i;
157019d6b8fSAnthony Liguori     struct vhd_footer* footer;
158019d6b8fSAnthony Liguori     struct vhd_dyndisk_header* dyndisk_header;
159019d6b8fSAnthony Liguori     uint8_t buf[HEADER_SIZE];
160019d6b8fSAnthony Liguori     uint32_t checksum;
161019d6b8fSAnthony Liguori 
162019d6b8fSAnthony Liguori     ret = bdrv_file_open(&s->hd, filename, flags);
163019d6b8fSAnthony Liguori     if (ret < 0)
164019d6b8fSAnthony Liguori         return ret;
165019d6b8fSAnthony Liguori 
166019d6b8fSAnthony Liguori     if (bdrv_pread(s->hd, 0, s->footer_buf, HEADER_SIZE) != HEADER_SIZE)
167019d6b8fSAnthony Liguori         goto fail;
168019d6b8fSAnthony Liguori 
169019d6b8fSAnthony Liguori     footer = (struct vhd_footer*) s->footer_buf;
170019d6b8fSAnthony Liguori     if (strncmp(footer->creator, "conectix", 8))
171019d6b8fSAnthony Liguori         goto fail;
172019d6b8fSAnthony Liguori 
173019d6b8fSAnthony Liguori     checksum = be32_to_cpu(footer->checksum);
174019d6b8fSAnthony Liguori     footer->checksum = 0;
175019d6b8fSAnthony Liguori     if (vpc_checksum(s->footer_buf, HEADER_SIZE) != checksum)
176019d6b8fSAnthony Liguori         fprintf(stderr, "block-vpc: The header checksum of '%s' is "
177019d6b8fSAnthony Liguori             "incorrect.\n", filename);
178019d6b8fSAnthony Liguori 
179019d6b8fSAnthony Liguori     // The visible size of a image in Virtual PC depends on the geometry
180019d6b8fSAnthony Liguori     // rather than on the size stored in the footer (the size in the footer
181019d6b8fSAnthony Liguori     // is too large usually)
182019d6b8fSAnthony Liguori     bs->total_sectors = (int64_t)
183019d6b8fSAnthony Liguori         be16_to_cpu(footer->cyls) * footer->heads * footer->secs_per_cyl;
184019d6b8fSAnthony Liguori 
185019d6b8fSAnthony Liguori     if (bdrv_pread(s->hd, be64_to_cpu(footer->data_offset), buf, HEADER_SIZE)
186019d6b8fSAnthony Liguori             != HEADER_SIZE)
187019d6b8fSAnthony Liguori         goto fail;
188019d6b8fSAnthony Liguori 
189019d6b8fSAnthony Liguori     dyndisk_header = (struct vhd_dyndisk_header*) buf;
190019d6b8fSAnthony Liguori 
191019d6b8fSAnthony Liguori     if (strncmp(dyndisk_header->magic, "cxsparse", 8))
192019d6b8fSAnthony Liguori         goto fail;
193019d6b8fSAnthony Liguori 
194019d6b8fSAnthony Liguori 
195019d6b8fSAnthony Liguori     s->block_size = be32_to_cpu(dyndisk_header->block_size);
196019d6b8fSAnthony Liguori     s->bitmap_size = ((s->block_size / (8 * 512)) + 511) & ~511;
197019d6b8fSAnthony Liguori 
198019d6b8fSAnthony Liguori     s->max_table_entries = be32_to_cpu(dyndisk_header->max_table_entries);
199019d6b8fSAnthony Liguori     s->pagetable = qemu_malloc(s->max_table_entries * 4);
200019d6b8fSAnthony Liguori 
201019d6b8fSAnthony Liguori     s->bat_offset = be64_to_cpu(dyndisk_header->table_offset);
202019d6b8fSAnthony Liguori     if (bdrv_pread(s->hd, s->bat_offset, s->pagetable,
203019d6b8fSAnthony Liguori             s->max_table_entries * 4) != s->max_table_entries * 4)
204019d6b8fSAnthony Liguori 	    goto fail;
205019d6b8fSAnthony Liguori 
206019d6b8fSAnthony Liguori     s->free_data_block_offset =
207019d6b8fSAnthony Liguori         (s->bat_offset + (s->max_table_entries * 4) + 511) & ~511;
208019d6b8fSAnthony Liguori 
209019d6b8fSAnthony Liguori     for (i = 0; i < s->max_table_entries; i++) {
210019d6b8fSAnthony Liguori         be32_to_cpus(&s->pagetable[i]);
211019d6b8fSAnthony Liguori         if (s->pagetable[i] != 0xFFFFFFFF) {
212019d6b8fSAnthony Liguori             int64_t next = (512 * (int64_t) s->pagetable[i]) +
213019d6b8fSAnthony Liguori                 s->bitmap_size + s->block_size;
214019d6b8fSAnthony Liguori 
215019d6b8fSAnthony Liguori             if (next> s->free_data_block_offset)
216019d6b8fSAnthony Liguori                 s->free_data_block_offset = next;
217019d6b8fSAnthony Liguori         }
218019d6b8fSAnthony Liguori     }
219019d6b8fSAnthony Liguori 
220019d6b8fSAnthony Liguori     s->last_bitmap_offset = (int64_t) -1;
221019d6b8fSAnthony Liguori 
222019d6b8fSAnthony Liguori #ifdef CACHE
223019d6b8fSAnthony Liguori     s->pageentry_u8 = qemu_malloc(512);
224019d6b8fSAnthony Liguori     s->pageentry_u32 = s->pageentry_u8;
225019d6b8fSAnthony Liguori     s->pageentry_u16 = s->pageentry_u8;
226019d6b8fSAnthony Liguori     s->last_pagetable = -1;
227019d6b8fSAnthony Liguori #endif
228019d6b8fSAnthony Liguori 
229019d6b8fSAnthony Liguori     return 0;
230019d6b8fSAnthony Liguori  fail:
231019d6b8fSAnthony Liguori     bdrv_delete(s->hd);
232019d6b8fSAnthony Liguori     return -1;
233019d6b8fSAnthony Liguori }
234019d6b8fSAnthony Liguori 
235019d6b8fSAnthony Liguori /*
236019d6b8fSAnthony Liguori  * Returns the absolute byte offset of the given sector in the image file.
237019d6b8fSAnthony Liguori  * If the sector is not allocated, -1 is returned instead.
238019d6b8fSAnthony Liguori  *
239019d6b8fSAnthony Liguori  * The parameter write must be 1 if the offset will be used for a write
240019d6b8fSAnthony Liguori  * operation (the block bitmaps is updated then), 0 otherwise.
241019d6b8fSAnthony Liguori  */
242019d6b8fSAnthony Liguori static inline int64_t get_sector_offset(BlockDriverState *bs,
243019d6b8fSAnthony Liguori     int64_t sector_num, int write)
244019d6b8fSAnthony Liguori {
245019d6b8fSAnthony Liguori     BDRVVPCState *s = bs->opaque;
246019d6b8fSAnthony Liguori     uint64_t offset = sector_num * 512;
247019d6b8fSAnthony Liguori     uint64_t bitmap_offset, block_offset;
248019d6b8fSAnthony Liguori     uint32_t pagetable_index, pageentry_index;
249019d6b8fSAnthony Liguori 
250019d6b8fSAnthony Liguori     pagetable_index = offset / s->block_size;
251019d6b8fSAnthony Liguori     pageentry_index = (offset % s->block_size) / 512;
252019d6b8fSAnthony Liguori 
253019d6b8fSAnthony Liguori     if (pagetable_index >= s->max_table_entries || s->pagetable[pagetable_index] == 0xffffffff)
254019d6b8fSAnthony Liguori         return -1; // not allocated
255019d6b8fSAnthony Liguori 
256019d6b8fSAnthony Liguori     bitmap_offset = 512 * (uint64_t) s->pagetable[pagetable_index];
257019d6b8fSAnthony Liguori     block_offset = bitmap_offset + s->bitmap_size + (512 * pageentry_index);
258019d6b8fSAnthony Liguori 
259019d6b8fSAnthony Liguori     // We must ensure that we don't write to any sectors which are marked as
260019d6b8fSAnthony Liguori     // unused in the bitmap. We get away with setting all bits in the block
261019d6b8fSAnthony Liguori     // bitmap each time we write to a new block. This might cause Virtual PC to
262019d6b8fSAnthony Liguori     // miss sparse read optimization, but it's not a problem in terms of
263019d6b8fSAnthony Liguori     // correctness.
264019d6b8fSAnthony Liguori     if (write && (s->last_bitmap_offset != bitmap_offset)) {
265019d6b8fSAnthony Liguori         uint8_t bitmap[s->bitmap_size];
266019d6b8fSAnthony Liguori 
267019d6b8fSAnthony Liguori         s->last_bitmap_offset = bitmap_offset;
268019d6b8fSAnthony Liguori         memset(bitmap, 0xff, s->bitmap_size);
269019d6b8fSAnthony Liguori         bdrv_pwrite(s->hd, bitmap_offset, bitmap, s->bitmap_size);
270019d6b8fSAnthony Liguori     }
271019d6b8fSAnthony Liguori 
272019d6b8fSAnthony Liguori //    printf("sector: %" PRIx64 ", index: %x, offset: %x, bioff: %" PRIx64 ", bloff: %" PRIx64 "\n",
273019d6b8fSAnthony Liguori //	sector_num, pagetable_index, pageentry_index,
274019d6b8fSAnthony Liguori //	bitmap_offset, block_offset);
275019d6b8fSAnthony Liguori 
276019d6b8fSAnthony Liguori // disabled by reason
277019d6b8fSAnthony Liguori #if 0
278019d6b8fSAnthony Liguori #ifdef CACHE
279019d6b8fSAnthony Liguori     if (bitmap_offset != s->last_bitmap)
280019d6b8fSAnthony Liguori     {
281019d6b8fSAnthony Liguori 	lseek(s->fd, bitmap_offset, SEEK_SET);
282019d6b8fSAnthony Liguori 
283019d6b8fSAnthony Liguori 	s->last_bitmap = bitmap_offset;
284019d6b8fSAnthony Liguori 
285019d6b8fSAnthony Liguori 	// Scary! Bitmap is stored as big endian 32bit entries,
286019d6b8fSAnthony Liguori 	// while we used to look it up byte by byte
287019d6b8fSAnthony Liguori 	read(s->fd, s->pageentry_u8, 512);
288019d6b8fSAnthony Liguori 	for (i = 0; i < 128; i++)
289019d6b8fSAnthony Liguori 	    be32_to_cpus(&s->pageentry_u32[i]);
290019d6b8fSAnthony Liguori     }
291019d6b8fSAnthony Liguori 
292019d6b8fSAnthony Liguori     if ((s->pageentry_u8[pageentry_index / 8] >> (pageentry_index % 8)) & 1)
293019d6b8fSAnthony Liguori 	return -1;
294019d6b8fSAnthony Liguori #else
295019d6b8fSAnthony Liguori     lseek(s->fd, bitmap_offset + (pageentry_index / 8), SEEK_SET);
296019d6b8fSAnthony Liguori 
297019d6b8fSAnthony Liguori     read(s->fd, &bitmap_entry, 1);
298019d6b8fSAnthony Liguori 
299019d6b8fSAnthony Liguori     if ((bitmap_entry >> (pageentry_index % 8)) & 1)
300019d6b8fSAnthony Liguori 	return -1; // not allocated
301019d6b8fSAnthony Liguori #endif
302019d6b8fSAnthony Liguori #endif
303019d6b8fSAnthony Liguori 
304019d6b8fSAnthony Liguori     return block_offset;
305019d6b8fSAnthony Liguori }
306019d6b8fSAnthony Liguori 
307019d6b8fSAnthony Liguori /*
308019d6b8fSAnthony Liguori  * Writes the footer to the end of the image file. This is needed when the
309019d6b8fSAnthony Liguori  * file grows as it overwrites the old footer
310019d6b8fSAnthony Liguori  *
311019d6b8fSAnthony Liguori  * Returns 0 on success and < 0 on error
312019d6b8fSAnthony Liguori  */
313019d6b8fSAnthony Liguori static int rewrite_footer(BlockDriverState* bs)
314019d6b8fSAnthony Liguori {
315019d6b8fSAnthony Liguori     int ret;
316019d6b8fSAnthony Liguori     BDRVVPCState *s = bs->opaque;
317019d6b8fSAnthony Liguori     int64_t offset = s->free_data_block_offset;
318019d6b8fSAnthony Liguori 
319019d6b8fSAnthony Liguori     ret = bdrv_pwrite(s->hd, offset, s->footer_buf, HEADER_SIZE);
320019d6b8fSAnthony Liguori     if (ret < 0)
321019d6b8fSAnthony Liguori         return ret;
322019d6b8fSAnthony Liguori 
323019d6b8fSAnthony Liguori     return 0;
324019d6b8fSAnthony Liguori }
325019d6b8fSAnthony Liguori 
326019d6b8fSAnthony Liguori /*
327019d6b8fSAnthony Liguori  * Allocates a new block. This involves writing a new footer and updating
328019d6b8fSAnthony Liguori  * the Block Allocation Table to use the space at the old end of the image
329019d6b8fSAnthony Liguori  * file (overwriting the old footer)
330019d6b8fSAnthony Liguori  *
331019d6b8fSAnthony Liguori  * Returns the sectors' offset in the image file on success and < 0 on error
332019d6b8fSAnthony Liguori  */
333019d6b8fSAnthony Liguori static int64_t alloc_block(BlockDriverState* bs, int64_t sector_num)
334019d6b8fSAnthony Liguori {
335019d6b8fSAnthony Liguori     BDRVVPCState *s = bs->opaque;
336019d6b8fSAnthony Liguori     int64_t bat_offset;
337019d6b8fSAnthony Liguori     uint32_t index, bat_value;
338019d6b8fSAnthony Liguori     int ret;
339019d6b8fSAnthony Liguori     uint8_t bitmap[s->bitmap_size];
340019d6b8fSAnthony Liguori 
341019d6b8fSAnthony Liguori     // Check if sector_num is valid
342019d6b8fSAnthony Liguori     if ((sector_num < 0) || (sector_num > bs->total_sectors))
343019d6b8fSAnthony Liguori         return -1;
344019d6b8fSAnthony Liguori 
345019d6b8fSAnthony Liguori     // Write entry into in-memory BAT
346019d6b8fSAnthony Liguori     index = (sector_num * 512) / s->block_size;
347019d6b8fSAnthony Liguori     if (s->pagetable[index] != 0xFFFFFFFF)
348019d6b8fSAnthony Liguori         return -1;
349019d6b8fSAnthony Liguori 
350019d6b8fSAnthony Liguori     s->pagetable[index] = s->free_data_block_offset / 512;
351019d6b8fSAnthony Liguori 
352019d6b8fSAnthony Liguori     // Initialize the block's bitmap
353019d6b8fSAnthony Liguori     memset(bitmap, 0xff, s->bitmap_size);
354019d6b8fSAnthony Liguori     bdrv_pwrite(s->hd, s->free_data_block_offset, bitmap, s->bitmap_size);
355019d6b8fSAnthony Liguori 
356019d6b8fSAnthony Liguori     // Write new footer (the old one will be overwritten)
357019d6b8fSAnthony Liguori     s->free_data_block_offset += s->block_size + s->bitmap_size;
358019d6b8fSAnthony Liguori     ret = rewrite_footer(bs);
359019d6b8fSAnthony Liguori     if (ret < 0)
360019d6b8fSAnthony Liguori         goto fail;
361019d6b8fSAnthony Liguori 
362019d6b8fSAnthony Liguori     // Write BAT entry to disk
363019d6b8fSAnthony Liguori     bat_offset = s->bat_offset + (4 * index);
364019d6b8fSAnthony Liguori     bat_value = be32_to_cpu(s->pagetable[index]);
365019d6b8fSAnthony Liguori     ret = bdrv_pwrite(s->hd, bat_offset, &bat_value, 4);
366019d6b8fSAnthony Liguori     if (ret < 0)
367019d6b8fSAnthony Liguori         goto fail;
368019d6b8fSAnthony Liguori 
369019d6b8fSAnthony Liguori     return get_sector_offset(bs, sector_num, 0);
370019d6b8fSAnthony Liguori 
371019d6b8fSAnthony Liguori fail:
372019d6b8fSAnthony Liguori     s->free_data_block_offset -= (s->block_size + s->bitmap_size);
373019d6b8fSAnthony Liguori     return -1;
374019d6b8fSAnthony Liguori }
375019d6b8fSAnthony Liguori 
376019d6b8fSAnthony Liguori static int vpc_read(BlockDriverState *bs, int64_t sector_num,
377019d6b8fSAnthony Liguori                     uint8_t *buf, int nb_sectors)
378019d6b8fSAnthony Liguori {
379019d6b8fSAnthony Liguori     BDRVVPCState *s = bs->opaque;
380019d6b8fSAnthony Liguori     int ret;
381019d6b8fSAnthony Liguori     int64_t offset;
382019d6b8fSAnthony Liguori 
383019d6b8fSAnthony Liguori     while (nb_sectors > 0) {
384019d6b8fSAnthony Liguori         offset = get_sector_offset(bs, sector_num, 0);
385019d6b8fSAnthony Liguori 
386019d6b8fSAnthony Liguori         if (offset == -1) {
387019d6b8fSAnthony Liguori             memset(buf, 0, 512);
388019d6b8fSAnthony Liguori         } else {
389019d6b8fSAnthony Liguori             ret = bdrv_pread(s->hd, offset, buf, 512);
390019d6b8fSAnthony Liguori             if (ret != 512)
391019d6b8fSAnthony Liguori                 return -1;
392019d6b8fSAnthony Liguori         }
393019d6b8fSAnthony Liguori 
394019d6b8fSAnthony Liguori         nb_sectors--;
395019d6b8fSAnthony Liguori         sector_num++;
396019d6b8fSAnthony Liguori         buf += 512;
397019d6b8fSAnthony Liguori     }
398019d6b8fSAnthony Liguori     return 0;
399019d6b8fSAnthony Liguori }
400019d6b8fSAnthony Liguori 
401019d6b8fSAnthony Liguori static int vpc_write(BlockDriverState *bs, int64_t sector_num,
402019d6b8fSAnthony Liguori     const uint8_t *buf, int nb_sectors)
403019d6b8fSAnthony Liguori {
404019d6b8fSAnthony Liguori     BDRVVPCState *s = bs->opaque;
405019d6b8fSAnthony Liguori     int64_t offset;
406019d6b8fSAnthony Liguori     int ret;
407019d6b8fSAnthony Liguori 
408019d6b8fSAnthony Liguori     while (nb_sectors > 0) {
409019d6b8fSAnthony Liguori         offset = get_sector_offset(bs, sector_num, 1);
410019d6b8fSAnthony Liguori 
411019d6b8fSAnthony Liguori         if (offset == -1) {
412019d6b8fSAnthony Liguori             offset = alloc_block(bs, sector_num);
413019d6b8fSAnthony Liguori             if (offset < 0)
414019d6b8fSAnthony Liguori                 return -1;
415019d6b8fSAnthony Liguori         }
416019d6b8fSAnthony Liguori 
417019d6b8fSAnthony Liguori         ret = bdrv_pwrite(s->hd, offset, buf, 512);
418019d6b8fSAnthony Liguori         if (ret != 512)
419019d6b8fSAnthony Liguori             return -1;
420019d6b8fSAnthony Liguori 
421019d6b8fSAnthony Liguori         nb_sectors--;
422019d6b8fSAnthony Liguori         sector_num++;
423019d6b8fSAnthony Liguori         buf += 512;
424019d6b8fSAnthony Liguori     }
425019d6b8fSAnthony Liguori 
426019d6b8fSAnthony Liguori     return 0;
427019d6b8fSAnthony Liguori }
428019d6b8fSAnthony Liguori 
429019d6b8fSAnthony Liguori 
430019d6b8fSAnthony Liguori /*
431019d6b8fSAnthony Liguori  * Calculates the number of cylinders, heads and sectors per cylinder
432019d6b8fSAnthony Liguori  * based on a given number of sectors. This is the algorithm described
433019d6b8fSAnthony Liguori  * in the VHD specification.
434019d6b8fSAnthony Liguori  *
435019d6b8fSAnthony Liguori  * Note that the geometry doesn't always exactly match total_sectors but
436019d6b8fSAnthony Liguori  * may round it down.
437019d6b8fSAnthony Liguori  *
438019d6b8fSAnthony Liguori  * Returns 0 on success, -EFBIG if the size is larger than 127 GB
439019d6b8fSAnthony Liguori  */
440019d6b8fSAnthony Liguori static int calculate_geometry(int64_t total_sectors, uint16_t* cyls,
441019d6b8fSAnthony Liguori     uint8_t* heads, uint8_t* secs_per_cyl)
442019d6b8fSAnthony Liguori {
443019d6b8fSAnthony Liguori     uint32_t cyls_times_heads;
444019d6b8fSAnthony Liguori 
445019d6b8fSAnthony Liguori     if (total_sectors > 65535 * 16 * 255)
446019d6b8fSAnthony Liguori         return -EFBIG;
447019d6b8fSAnthony Liguori 
448019d6b8fSAnthony Liguori     if (total_sectors > 65535 * 16 * 63) {
449019d6b8fSAnthony Liguori         *secs_per_cyl = 255;
450019d6b8fSAnthony Liguori         *heads = 16;
451019d6b8fSAnthony Liguori         cyls_times_heads = total_sectors / *secs_per_cyl;
452019d6b8fSAnthony Liguori     } else {
453019d6b8fSAnthony Liguori         *secs_per_cyl = 17;
454019d6b8fSAnthony Liguori         cyls_times_heads = total_sectors / *secs_per_cyl;
455019d6b8fSAnthony Liguori         *heads = (cyls_times_heads + 1023) / 1024;
456019d6b8fSAnthony Liguori 
457019d6b8fSAnthony Liguori         if (*heads < 4)
458019d6b8fSAnthony Liguori             *heads = 4;
459019d6b8fSAnthony Liguori 
460019d6b8fSAnthony Liguori         if (cyls_times_heads >= (*heads * 1024) || *heads > 16) {
461019d6b8fSAnthony Liguori             *secs_per_cyl = 31;
462019d6b8fSAnthony Liguori             *heads = 16;
463019d6b8fSAnthony Liguori             cyls_times_heads = total_sectors / *secs_per_cyl;
464019d6b8fSAnthony Liguori         }
465019d6b8fSAnthony Liguori 
466019d6b8fSAnthony Liguori         if (cyls_times_heads >= (*heads * 1024)) {
467019d6b8fSAnthony Liguori             *secs_per_cyl = 63;
468019d6b8fSAnthony Liguori             *heads = 16;
469019d6b8fSAnthony Liguori             cyls_times_heads = total_sectors / *secs_per_cyl;
470019d6b8fSAnthony Liguori         }
471019d6b8fSAnthony Liguori     }
472019d6b8fSAnthony Liguori 
473019d6b8fSAnthony Liguori     // Note: Rounding up deviates from the Virtual PC behaviour
474019d6b8fSAnthony Liguori     // However, we need this to avoid truncating images in qemu-img convert
475019d6b8fSAnthony Liguori     *cyls = (cyls_times_heads + *heads - 1) / *heads;
476019d6b8fSAnthony Liguori 
477019d6b8fSAnthony Liguori     return 0;
478019d6b8fSAnthony Liguori }
479019d6b8fSAnthony Liguori 
4800e7e1989SKevin Wolf static int vpc_create(const char *filename, QEMUOptionParameter *options)
481019d6b8fSAnthony Liguori {
482019d6b8fSAnthony Liguori     uint8_t buf[1024];
483019d6b8fSAnthony Liguori     struct vhd_footer* footer = (struct vhd_footer*) buf;
484019d6b8fSAnthony Liguori     struct vhd_dyndisk_header* dyndisk_header =
485019d6b8fSAnthony Liguori         (struct vhd_dyndisk_header*) buf;
486019d6b8fSAnthony Liguori     int fd, i;
487019d6b8fSAnthony Liguori     uint16_t cyls;
488019d6b8fSAnthony Liguori     uint8_t heads;
489019d6b8fSAnthony Liguori     uint8_t secs_per_cyl;
490019d6b8fSAnthony Liguori     size_t block_size, num_bat_entries;
4910e7e1989SKevin Wolf     int64_t total_sectors = 0;
492019d6b8fSAnthony Liguori 
4930e7e1989SKevin Wolf     // Read out options
4940e7e1989SKevin Wolf     while (options && options->name) {
4950e7e1989SKevin Wolf         if (!strcmp(options->name, "size")) {
4960e7e1989SKevin Wolf             total_sectors = options->value.n / 512;
4970e7e1989SKevin Wolf         }
4980e7e1989SKevin Wolf         options++;
4990e7e1989SKevin Wolf     }
500019d6b8fSAnthony Liguori 
5010e7e1989SKevin Wolf     // Create the file
502019d6b8fSAnthony Liguori     fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
503019d6b8fSAnthony Liguori     if (fd < 0)
504019d6b8fSAnthony Liguori         return -EIO;
505019d6b8fSAnthony Liguori 
506019d6b8fSAnthony Liguori     // Calculate matching total_size and geometry
507019d6b8fSAnthony Liguori     if (calculate_geometry(total_sectors, &cyls, &heads, &secs_per_cyl))
508019d6b8fSAnthony Liguori         return -EFBIG;
509019d6b8fSAnthony Liguori     total_sectors = (int64_t) cyls * heads * secs_per_cyl;
510019d6b8fSAnthony Liguori 
511019d6b8fSAnthony Liguori     // Prepare the Hard Disk Footer
512019d6b8fSAnthony Liguori     memset(buf, 0, 1024);
513019d6b8fSAnthony Liguori 
514*5ec4d682SNathan Froyd     memcpy(footer->creator, "conectix", 8);
515019d6b8fSAnthony Liguori     // TODO Check if "qemu" creator_app is ok for VPC
516*5ec4d682SNathan Froyd     memcpy(footer->creator_app, "qemu", 4);
517*5ec4d682SNathan Froyd     memcpy(footer->creator_os, "Wi2k", 4);
518019d6b8fSAnthony Liguori 
519019d6b8fSAnthony Liguori     footer->features = be32_to_cpu(0x02);
520019d6b8fSAnthony Liguori     footer->version = be32_to_cpu(0x00010000);
521019d6b8fSAnthony Liguori     footer->data_offset = be64_to_cpu(HEADER_SIZE);
522019d6b8fSAnthony Liguori     footer->timestamp = be32_to_cpu(time(NULL) - VHD_TIMESTAMP_BASE);
523019d6b8fSAnthony Liguori 
524019d6b8fSAnthony Liguori     // Version of Virtual PC 2007
525019d6b8fSAnthony Liguori     footer->major = be16_to_cpu(0x0005);
526019d6b8fSAnthony Liguori     footer->minor =be16_to_cpu(0x0003);
527019d6b8fSAnthony Liguori 
528019d6b8fSAnthony Liguori     footer->orig_size = be64_to_cpu(total_sectors * 512);
529019d6b8fSAnthony Liguori     footer->size = be64_to_cpu(total_sectors * 512);
530019d6b8fSAnthony Liguori 
531019d6b8fSAnthony Liguori     footer->cyls = be16_to_cpu(cyls);
532019d6b8fSAnthony Liguori     footer->heads = heads;
533019d6b8fSAnthony Liguori     footer->secs_per_cyl = secs_per_cyl;
534019d6b8fSAnthony Liguori 
535019d6b8fSAnthony Liguori     footer->type = be32_to_cpu(VHD_DYNAMIC);
536019d6b8fSAnthony Liguori 
537019d6b8fSAnthony Liguori     // TODO uuid is missing
538019d6b8fSAnthony Liguori 
539019d6b8fSAnthony Liguori     footer->checksum = be32_to_cpu(vpc_checksum(buf, HEADER_SIZE));
540019d6b8fSAnthony Liguori 
541019d6b8fSAnthony Liguori     // Write the footer (twice: at the beginning and at the end)
542019d6b8fSAnthony Liguori     block_size = 0x200000;
543019d6b8fSAnthony Liguori     num_bat_entries = (total_sectors + block_size / 512) / (block_size / 512);
544019d6b8fSAnthony Liguori 
545019d6b8fSAnthony Liguori     if (write(fd, buf, HEADER_SIZE) != HEADER_SIZE)
546019d6b8fSAnthony Liguori         return -EIO;
547019d6b8fSAnthony Liguori 
548019d6b8fSAnthony Liguori     if (lseek(fd, 1536 + ((num_bat_entries * 4 + 511) & ~511), SEEK_SET) < 0)
549019d6b8fSAnthony Liguori         return -EIO;
550019d6b8fSAnthony Liguori     if (write(fd, buf, HEADER_SIZE) != HEADER_SIZE)
551019d6b8fSAnthony Liguori         return -EIO;
552019d6b8fSAnthony Liguori 
553019d6b8fSAnthony Liguori     // Write the initial BAT
554019d6b8fSAnthony Liguori     if (lseek(fd, 3 * 512, SEEK_SET) < 0)
555019d6b8fSAnthony Liguori         return -EIO;
556019d6b8fSAnthony Liguori 
557019d6b8fSAnthony Liguori     memset(buf, 0xFF, 512);
558019d6b8fSAnthony Liguori     for (i = 0; i < (num_bat_entries * 4 + 511) / 512; i++)
559019d6b8fSAnthony Liguori         if (write(fd, buf, 512) != 512)
560019d6b8fSAnthony Liguori             return -EIO;
561019d6b8fSAnthony Liguori 
562019d6b8fSAnthony Liguori 
563019d6b8fSAnthony Liguori     // Prepare the Dynamic Disk Header
564019d6b8fSAnthony Liguori     memset(buf, 0, 1024);
565019d6b8fSAnthony Liguori 
566*5ec4d682SNathan Froyd     memcpy(dyndisk_header->magic, "cxsparse", 8);
567019d6b8fSAnthony Liguori 
568019d6b8fSAnthony Liguori     dyndisk_header->data_offset = be64_to_cpu(0xFFFFFFFF);
569019d6b8fSAnthony Liguori     dyndisk_header->table_offset = be64_to_cpu(3 * 512);
570019d6b8fSAnthony Liguori     dyndisk_header->version = be32_to_cpu(0x00010000);
571019d6b8fSAnthony Liguori     dyndisk_header->block_size = be32_to_cpu(block_size);
572019d6b8fSAnthony Liguori     dyndisk_header->max_table_entries = be32_to_cpu(num_bat_entries);
573019d6b8fSAnthony Liguori 
574019d6b8fSAnthony Liguori     dyndisk_header->checksum = be32_to_cpu(vpc_checksum(buf, 1024));
575019d6b8fSAnthony Liguori 
576019d6b8fSAnthony Liguori     // Write the header
577019d6b8fSAnthony Liguori     if (lseek(fd, 512, SEEK_SET) < 0)
578019d6b8fSAnthony Liguori         return -EIO;
579019d6b8fSAnthony Liguori     if (write(fd, buf, 1024) != 1024)
580019d6b8fSAnthony Liguori         return -EIO;
581019d6b8fSAnthony Liguori 
582019d6b8fSAnthony Liguori     close(fd);
583019d6b8fSAnthony Liguori     return 0;
584019d6b8fSAnthony Liguori }
585019d6b8fSAnthony Liguori 
586019d6b8fSAnthony Liguori static void vpc_close(BlockDriverState *bs)
587019d6b8fSAnthony Liguori {
588019d6b8fSAnthony Liguori     BDRVVPCState *s = bs->opaque;
589019d6b8fSAnthony Liguori     qemu_free(s->pagetable);
590019d6b8fSAnthony Liguori #ifdef CACHE
591019d6b8fSAnthony Liguori     qemu_free(s->pageentry_u8);
592019d6b8fSAnthony Liguori #endif
593019d6b8fSAnthony Liguori     bdrv_delete(s->hd);
594019d6b8fSAnthony Liguori }
595019d6b8fSAnthony Liguori 
5960e7e1989SKevin Wolf static QEMUOptionParameter vpc_create_options[] = {
597db08adf5SKevin Wolf     {
598db08adf5SKevin Wolf         .name = BLOCK_OPT_SIZE,
599db08adf5SKevin Wolf         .type = OPT_SIZE,
600db08adf5SKevin Wolf         .help = "Virtual disk size"
601db08adf5SKevin Wolf     },
6020e7e1989SKevin Wolf     { NULL }
6030e7e1989SKevin Wolf };
6040e7e1989SKevin Wolf 
605019d6b8fSAnthony Liguori static BlockDriver bdrv_vpc = {
606019d6b8fSAnthony Liguori     .format_name	= "vpc",
607019d6b8fSAnthony Liguori     .instance_size	= sizeof(BDRVVPCState),
608019d6b8fSAnthony Liguori     .bdrv_probe		= vpc_probe,
609019d6b8fSAnthony Liguori     .bdrv_open		= vpc_open,
610019d6b8fSAnthony Liguori     .bdrv_read		= vpc_read,
611019d6b8fSAnthony Liguori     .bdrv_write		= vpc_write,
612019d6b8fSAnthony Liguori     .bdrv_close		= vpc_close,
613019d6b8fSAnthony Liguori     .bdrv_create	= vpc_create,
6140e7e1989SKevin Wolf 
6150e7e1989SKevin Wolf     .create_options = vpc_create_options,
616019d6b8fSAnthony Liguori };
617019d6b8fSAnthony Liguori 
618019d6b8fSAnthony Liguori static void bdrv_vpc_init(void)
619019d6b8fSAnthony Liguori {
620019d6b8fSAnthony Liguori     bdrv_register(&bdrv_vpc);
621019d6b8fSAnthony Liguori }
622019d6b8fSAnthony Liguori 
623019d6b8fSAnthony Liguori block_init(bdrv_vpc_init);
624