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/*
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* Block driver for Conectix/Microsoft Virtual PC images
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*
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* Copyright (c) 2005 Alex Beregszaszi
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* Copyright (c) 2009 Kevin Wolf <kwolf@suse.de>
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "qemu-common.h" |
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#include "block_int.h" |
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#include "module.h" |
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|
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/**************************************************************/
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|
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#define HEADER_SIZE 512 |
32 |
|
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//#define CACHE
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|
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enum vhd_type {
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VHD_FIXED = 2,
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VHD_DYNAMIC = 3,
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VHD_DIFFERENCING = 4,
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}; |
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|
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// Seconds since Jan 1, 2000 0:00:00 (UTC)
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#define VHD_TIMESTAMP_BASE 946684800 |
43 |
|
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// always big-endian
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struct vhd_footer {
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char creator[8]; // "conectix" |
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uint32_t features; |
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uint32_t version; |
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|
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// Offset of next header structure, 0xFFFFFFFF if none
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uint64_t data_offset; |
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|
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// Seconds since Jan 1, 2000 0:00:00 (UTC)
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uint32_t timestamp; |
55 |
|
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char creator_app[4]; // "vpc " |
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uint16_t major; |
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uint16_t minor; |
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char creator_os[4]; // "Wi2k" |
60 |
|
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uint64_t orig_size; |
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uint64_t size; |
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|
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uint16_t cyls; |
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uint8_t heads; |
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uint8_t secs_per_cyl; |
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|
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uint32_t type; |
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|
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// Checksum of the Hard Disk Footer ("one's complement of the sum of all
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// the bytes in the footer without the checksum field")
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uint32_t checksum; |
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|
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// UUID used to identify a parent hard disk (backing file)
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uint8_t uuid[16];
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|
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uint8_t in_saved_state; |
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}; |
79 |
|
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struct vhd_dyndisk_header {
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char magic[8]; // "cxsparse" |
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|
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// Offset of next header structure, 0xFFFFFFFF if none
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uint64_t data_offset; |
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|
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// Offset of the Block Allocation Table (BAT)
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uint64_t table_offset; |
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|
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uint32_t version; |
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uint32_t max_table_entries; // 32bit/entry
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|
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// 2 MB by default, must be a power of two
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uint32_t block_size; |
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|
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uint32_t checksum; |
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uint8_t parent_uuid[16];
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uint32_t parent_timestamp; |
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uint32_t reserved; |
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|
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// Backing file name (in UTF-16)
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uint8_t parent_name[512];
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|
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struct {
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uint32_t platform; |
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uint32_t data_space; |
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uint32_t data_length; |
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uint32_t reserved; |
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uint64_t data_offset; |
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} parent_locator[8];
|
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}; |
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|
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typedef struct BDRVVPCState { |
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BlockDriverState *hd; |
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|
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uint8_t footer_buf[HEADER_SIZE]; |
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uint64_t free_data_block_offset; |
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int max_table_entries;
|
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uint32_t *pagetable; |
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uint64_t bat_offset; |
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uint64_t last_bitmap_offset; |
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|
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uint32_t block_size; |
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uint32_t bitmap_size; |
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|
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#ifdef CACHE
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uint8_t *pageentry_u8; |
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uint32_t *pageentry_u32; |
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uint16_t *pageentry_u16; |
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|
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uint64_t last_bitmap; |
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#endif
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} BDRVVPCState; |
133 |
|
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static uint32_t vpc_checksum(uint8_t* buf, size_t size)
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{ |
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uint32_t res = 0;
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int i;
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for (i = 0; i < size; i++) |
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res += buf[i]; |
141 |
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return ~res;
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} |
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|
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static int vpc_probe(const uint8_t *buf, int buf_size, const char *filename) |
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{ |
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if (buf_size >= 8 && !strncmp((char *)buf, "conectix", 8)) |
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return 100; |
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return 0; |
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} |
152 |
|
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static int vpc_open(BlockDriverState *bs, const char *filename, int flags) |
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{ |
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BDRVVPCState *s = bs->opaque; |
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int ret, i;
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struct vhd_footer* footer;
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struct vhd_dyndisk_header* dyndisk_header;
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uint8_t buf[HEADER_SIZE]; |
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uint32_t checksum; |
161 |
|
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ret = bdrv_file_open(&s->hd, filename, flags); |
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if (ret < 0) |
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return ret;
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|
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if (bdrv_pread(s->hd, 0, s->footer_buf, HEADER_SIZE) != HEADER_SIZE) |
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goto fail;
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footer = (struct vhd_footer*) s->footer_buf;
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if (strncmp(footer->creator, "conectix", 8)) |
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goto fail;
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|
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checksum = be32_to_cpu(footer->checksum); |
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footer->checksum = 0;
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if (vpc_checksum(s->footer_buf, HEADER_SIZE) != checksum)
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fprintf(stderr, "block-vpc: The header checksum of '%s' is "
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"incorrect.\n", filename);
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// The visible size of a image in Virtual PC depends on the geometry
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// rather than on the size stored in the footer (the size in the footer
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// is too large usually)
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bs->total_sectors = (int64_t) |
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be16_to_cpu(footer->cyls) * footer->heads * footer->secs_per_cyl; |
184 |
|
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if (bdrv_pread(s->hd, be64_to_cpu(footer->data_offset), buf, HEADER_SIZE)
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!= HEADER_SIZE) |
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goto fail;
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dyndisk_header = (struct vhd_dyndisk_header*) buf;
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|
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if (strncmp(dyndisk_header->magic, "cxsparse", 8)) |
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goto fail;
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|
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|
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s->block_size = be32_to_cpu(dyndisk_header->block_size); |
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s->bitmap_size = ((s->block_size / (8 * 512)) + 511) & ~511; |
197 |
|
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s->max_table_entries = be32_to_cpu(dyndisk_header->max_table_entries); |
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s->pagetable = qemu_malloc(s->max_table_entries * 4);
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s->bat_offset = be64_to_cpu(dyndisk_header->table_offset); |
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if (bdrv_pread(s->hd, s->bat_offset, s->pagetable,
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s->max_table_entries * 4) != s->max_table_entries * 4) |
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goto fail;
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205 |
|
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s->free_data_block_offset = |
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(s->bat_offset + (s->max_table_entries * 4) + 511) & ~511; |
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|
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for (i = 0; i < s->max_table_entries; i++) { |
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be32_to_cpus(&s->pagetable[i]); |
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if (s->pagetable[i] != 0xFFFFFFFF) { |
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int64_t next = (512 * (int64_t) s->pagetable[i]) +
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s->bitmap_size + s->block_size; |
214 |
|
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if (next> s->free_data_block_offset)
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s->free_data_block_offset = next; |
217 |
} |
218 |
} |
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s->last_bitmap_offset = (int64_t) -1;
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|
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#ifdef CACHE
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s->pageentry_u8 = qemu_malloc(512);
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s->pageentry_u32 = s->pageentry_u8; |
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s->pageentry_u16 = s->pageentry_u8; |
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s->last_pagetable = -1;
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#endif
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return 0; |
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fail:
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bdrv_delete(s->hd); |
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return -1; |
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} |
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|
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/*
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* Returns the absolute byte offset of the given sector in the image file.
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* If the sector is not allocated, -1 is returned instead.
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*
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* The parameter write must be 1 if the offset will be used for a write
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* operation (the block bitmaps is updated then), 0 otherwise.
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*/
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static inline int64_t get_sector_offset(BlockDriverState *bs, |
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int64_t sector_num, int write)
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{ |
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BDRVVPCState *s = bs->opaque; |
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uint64_t offset = sector_num * 512;
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uint64_t bitmap_offset, block_offset; |
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uint32_t pagetable_index, pageentry_index; |
249 |
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pagetable_index = offset / s->block_size; |
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pageentry_index = (offset % s->block_size) / 512;
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|
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if (pagetable_index >= s->max_table_entries || s->pagetable[pagetable_index] == 0xffffffff) |
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return -1; // not allocated |
255 |
|
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bitmap_offset = 512 * (uint64_t) s->pagetable[pagetable_index];
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block_offset = bitmap_offset + s->bitmap_size + (512 * pageentry_index);
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|
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// We must ensure that we don't write to any sectors which are marked as
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// unused in the bitmap. We get away with setting all bits in the block
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// bitmap each time we write to a new block. This might cause Virtual PC to
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// miss sparse read optimization, but it's not a problem in terms of
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// correctness.
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if (write && (s->last_bitmap_offset != bitmap_offset)) {
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uint8_t bitmap[s->bitmap_size]; |
266 |
|
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s->last_bitmap_offset = bitmap_offset; |
268 |
memset(bitmap, 0xff, s->bitmap_size);
|
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bdrv_pwrite(s->hd, bitmap_offset, bitmap, s->bitmap_size); |
270 |
} |
271 |
|
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// printf("sector: %" PRIx64 ", index: %x, offset: %x, bioff: %" PRIx64 ", bloff: %" PRIx64 "\n",
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// sector_num, pagetable_index, pageentry_index,
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// bitmap_offset, block_offset);
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275 |
|
276 |
// disabled by reason
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277 |
#if 0
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#ifdef CACHE
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if (bitmap_offset != s->last_bitmap)
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{
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lseek(s->fd, bitmap_offset, SEEK_SET);
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282 |
|
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s->last_bitmap = bitmap_offset;
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|
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// Scary! Bitmap is stored as big endian 32bit entries,
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286 |
// while we used to look it up byte by byte
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287 |
read(s->fd, s->pageentry_u8, 512);
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288 |
for (i = 0; i < 128; i++)
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be32_to_cpus(&s->pageentry_u32[i]);
|
290 |
}
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291 |
|
292 |
if ((s->pageentry_u8[pageentry_index / 8] >> (pageentry_index % 8)) & 1)
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return -1;
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294 |
#else
|
295 |
lseek(s->fd, bitmap_offset + (pageentry_index / 8), SEEK_SET);
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296 |
|
297 |
read(s->fd, &bitmap_entry, 1);
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298 |
|
299 |
if ((bitmap_entry >> (pageentry_index % 8)) & 1) |
300 |
return -1; // not allocated |
301 |
#endif
|
302 |
#endif
|
303 |
|
304 |
return block_offset;
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305 |
} |
306 |
|
307 |
/*
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308 |
* Writes the footer to the end of the image file. This is needed when the
|
309 |
* file grows as it overwrites the old footer
|
310 |
*
|
311 |
* Returns 0 on success and < 0 on error
|
312 |
*/
|
313 |
static int rewrite_footer(BlockDriverState* bs) |
314 |
{ |
315 |
int ret;
|
316 |
BDRVVPCState *s = bs->opaque; |
317 |
int64_t offset = s->free_data_block_offset; |
318 |
|
319 |
ret = bdrv_pwrite(s->hd, offset, s->footer_buf, HEADER_SIZE); |
320 |
if (ret < 0) |
321 |
return ret;
|
322 |
|
323 |
return 0; |
324 |
} |
325 |
|
326 |
/*
|
327 |
* Allocates a new block. This involves writing a new footer and updating
|
328 |
* the Block Allocation Table to use the space at the old end of the image
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329 |
* file (overwriting the old footer)
|
330 |
*
|
331 |
* Returns the sectors' offset in the image file on success and < 0 on error
|
332 |
*/
|
333 |
static int64_t alloc_block(BlockDriverState* bs, int64_t sector_num)
|
334 |
{ |
335 |
BDRVVPCState *s = bs->opaque; |
336 |
int64_t bat_offset; |
337 |
uint32_t index, bat_value; |
338 |
int ret;
|
339 |
uint8_t bitmap[s->bitmap_size]; |
340 |
|
341 |
// Check if sector_num is valid
|
342 |
if ((sector_num < 0) || (sector_num > bs->total_sectors)) |
343 |
return -1; |
344 |
|
345 |
// Write entry into in-memory BAT
|
346 |
index = (sector_num * 512) / s->block_size;
|
347 |
if (s->pagetable[index] != 0xFFFFFFFF) |
348 |
return -1; |
349 |
|
350 |
s->pagetable[index] = s->free_data_block_offset / 512;
|
351 |
|
352 |
// Initialize the block's bitmap
|
353 |
memset(bitmap, 0xff, s->bitmap_size);
|
354 |
bdrv_pwrite(s->hd, s->free_data_block_offset, bitmap, s->bitmap_size); |
355 |
|
356 |
// Write new footer (the old one will be overwritten)
|
357 |
s->free_data_block_offset += s->block_size + s->bitmap_size; |
358 |
ret = rewrite_footer(bs); |
359 |
if (ret < 0) |
360 |
goto fail;
|
361 |
|
362 |
// Write BAT entry to disk
|
363 |
bat_offset = s->bat_offset + (4 * index);
|
364 |
bat_value = be32_to_cpu(s->pagetable[index]); |
365 |
ret = bdrv_pwrite(s->hd, bat_offset, &bat_value, 4);
|
366 |
if (ret < 0) |
367 |
goto fail;
|
368 |
|
369 |
return get_sector_offset(bs, sector_num, 0); |
370 |
|
371 |
fail:
|
372 |
s->free_data_block_offset -= (s->block_size + s->bitmap_size); |
373 |
return -1; |
374 |
} |
375 |
|
376 |
static int vpc_read(BlockDriverState *bs, int64_t sector_num, |
377 |
uint8_t *buf, int nb_sectors)
|
378 |
{ |
379 |
BDRVVPCState *s = bs->opaque; |
380 |
int ret;
|
381 |
int64_t offset; |
382 |
|
383 |
while (nb_sectors > 0) { |
384 |
offset = get_sector_offset(bs, sector_num, 0);
|
385 |
|
386 |
if (offset == -1) { |
387 |
memset(buf, 0, 512); |
388 |
} else {
|
389 |
ret = bdrv_pread(s->hd, offset, buf, 512);
|
390 |
if (ret != 512) |
391 |
return -1; |
392 |
} |
393 |
|
394 |
nb_sectors--; |
395 |
sector_num++; |
396 |
buf += 512;
|
397 |
} |
398 |
return 0; |
399 |
} |
400 |
|
401 |
static int vpc_write(BlockDriverState *bs, int64_t sector_num, |
402 |
const uint8_t *buf, int nb_sectors) |
403 |
{ |
404 |
BDRVVPCState *s = bs->opaque; |
405 |
int64_t offset; |
406 |
int ret;
|
407 |
|
408 |
while (nb_sectors > 0) { |
409 |
offset = get_sector_offset(bs, sector_num, 1);
|
410 |
|
411 |
if (offset == -1) { |
412 |
offset = alloc_block(bs, sector_num); |
413 |
if (offset < 0) |
414 |
return -1; |
415 |
} |
416 |
|
417 |
ret = bdrv_pwrite(s->hd, offset, buf, 512);
|
418 |
if (ret != 512) |
419 |
return -1; |
420 |
|
421 |
nb_sectors--; |
422 |
sector_num++; |
423 |
buf += 512;
|
424 |
} |
425 |
|
426 |
return 0; |
427 |
} |
428 |
|
429 |
|
430 |
/*
|
431 |
* Calculates the number of cylinders, heads and sectors per cylinder
|
432 |
* based on a given number of sectors. This is the algorithm described
|
433 |
* in the VHD specification.
|
434 |
*
|
435 |
* Note that the geometry doesn't always exactly match total_sectors but
|
436 |
* may round it down.
|
437 |
*
|
438 |
* Returns 0 on success, -EFBIG if the size is larger than 127 GB
|
439 |
*/
|
440 |
static int calculate_geometry(int64_t total_sectors, uint16_t* cyls, |
441 |
uint8_t* heads, uint8_t* secs_per_cyl) |
442 |
{ |
443 |
uint32_t cyls_times_heads; |
444 |
|
445 |
if (total_sectors > 65535 * 16 * 255) |
446 |
return -EFBIG;
|
447 |
|
448 |
if (total_sectors > 65535 * 16 * 63) { |
449 |
*secs_per_cyl = 255;
|
450 |
*heads = 16;
|
451 |
cyls_times_heads = total_sectors / *secs_per_cyl; |
452 |
} else {
|
453 |
*secs_per_cyl = 17;
|
454 |
cyls_times_heads = total_sectors / *secs_per_cyl; |
455 |
*heads = (cyls_times_heads + 1023) / 1024; |
456 |
|
457 |
if (*heads < 4) |
458 |
*heads = 4;
|
459 |
|
460 |
if (cyls_times_heads >= (*heads * 1024) || *heads > 16) { |
461 |
*secs_per_cyl = 31;
|
462 |
*heads = 16;
|
463 |
cyls_times_heads = total_sectors / *secs_per_cyl; |
464 |
} |
465 |
|
466 |
if (cyls_times_heads >= (*heads * 1024)) { |
467 |
*secs_per_cyl = 63;
|
468 |
*heads = 16;
|
469 |
cyls_times_heads = total_sectors / *secs_per_cyl; |
470 |
} |
471 |
} |
472 |
|
473 |
// Note: Rounding up deviates from the Virtual PC behaviour
|
474 |
// However, we need this to avoid truncating images in qemu-img convert
|
475 |
*cyls = (cyls_times_heads + *heads - 1) / *heads;
|
476 |
|
477 |
return 0; |
478 |
} |
479 |
|
480 |
static int vpc_create(const char *filename, QEMUOptionParameter *options) |
481 |
{ |
482 |
uint8_t buf[1024];
|
483 |
struct vhd_footer* footer = (struct vhd_footer*) buf; |
484 |
struct vhd_dyndisk_header* dyndisk_header =
|
485 |
(struct vhd_dyndisk_header*) buf;
|
486 |
int fd, i;
|
487 |
uint16_t cyls; |
488 |
uint8_t heads; |
489 |
uint8_t secs_per_cyl; |
490 |
size_t block_size, num_bat_entries; |
491 |
int64_t total_sectors = 0;
|
492 |
|
493 |
// Read out options
|
494 |
while (options && options->name) {
|
495 |
if (!strcmp(options->name, "size")) { |
496 |
total_sectors = options->value.n / 512;
|
497 |
} |
498 |
options++; |
499 |
} |
500 |
|
501 |
// Create the file
|
502 |
fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
|
503 |
if (fd < 0) |
504 |
return -EIO;
|
505 |
|
506 |
// Calculate matching total_size and geometry
|
507 |
if (calculate_geometry(total_sectors, &cyls, &heads, &secs_per_cyl))
|
508 |
return -EFBIG;
|
509 |
total_sectors = (int64_t) cyls * heads * secs_per_cyl; |
510 |
|
511 |
// Prepare the Hard Disk Footer
|
512 |
memset(buf, 0, 1024); |
513 |
|
514 |
memcpy(footer->creator, "conectix", 8); |
515 |
// TODO Check if "qemu" creator_app is ok for VPC
|
516 |
memcpy(footer->creator_app, "qemu", 4); |
517 |
memcpy(footer->creator_os, "Wi2k", 4); |
518 |
|
519 |
footer->features = be32_to_cpu(0x02);
|
520 |
footer->version = be32_to_cpu(0x00010000);
|
521 |
footer->data_offset = be64_to_cpu(HEADER_SIZE); |
522 |
footer->timestamp = be32_to_cpu(time(NULL) - VHD_TIMESTAMP_BASE);
|
523 |
|
524 |
// Version of Virtual PC 2007
|
525 |
footer->major = be16_to_cpu(0x0005);
|
526 |
footer->minor =be16_to_cpu(0x0003);
|
527 |
|
528 |
footer->orig_size = be64_to_cpu(total_sectors * 512);
|
529 |
footer->size = be64_to_cpu(total_sectors * 512);
|
530 |
|
531 |
footer->cyls = be16_to_cpu(cyls); |
532 |
footer->heads = heads; |
533 |
footer->secs_per_cyl = secs_per_cyl; |
534 |
|
535 |
footer->type = be32_to_cpu(VHD_DYNAMIC); |
536 |
|
537 |
// TODO uuid is missing
|
538 |
|
539 |
footer->checksum = be32_to_cpu(vpc_checksum(buf, HEADER_SIZE)); |
540 |
|
541 |
// Write the footer (twice: at the beginning and at the end)
|
542 |
block_size = 0x200000;
|
543 |
num_bat_entries = (total_sectors + block_size / 512) / (block_size / 512); |
544 |
|
545 |
if (write(fd, buf, HEADER_SIZE) != HEADER_SIZE)
|
546 |
return -EIO;
|
547 |
|
548 |
if (lseek(fd, 1536 + ((num_bat_entries * 4 + 511) & ~511), SEEK_SET) < 0) |
549 |
return -EIO;
|
550 |
if (write(fd, buf, HEADER_SIZE) != HEADER_SIZE)
|
551 |
return -EIO;
|
552 |
|
553 |
// Write the initial BAT
|
554 |
if (lseek(fd, 3 * 512, SEEK_SET) < 0) |
555 |
return -EIO;
|
556 |
|
557 |
memset(buf, 0xFF, 512); |
558 |
for (i = 0; i < (num_bat_entries * 4 + 511) / 512; i++) |
559 |
if (write(fd, buf, 512) != 512) |
560 |
return -EIO;
|
561 |
|
562 |
|
563 |
// Prepare the Dynamic Disk Header
|
564 |
memset(buf, 0, 1024); |
565 |
|
566 |
memcpy(dyndisk_header->magic, "cxsparse", 8); |
567 |
|
568 |
dyndisk_header->data_offset = be64_to_cpu(0xFFFFFFFF);
|
569 |
dyndisk_header->table_offset = be64_to_cpu(3 * 512); |
570 |
dyndisk_header->version = be32_to_cpu(0x00010000);
|
571 |
dyndisk_header->block_size = be32_to_cpu(block_size); |
572 |
dyndisk_header->max_table_entries = be32_to_cpu(num_bat_entries); |
573 |
|
574 |
dyndisk_header->checksum = be32_to_cpu(vpc_checksum(buf, 1024));
|
575 |
|
576 |
// Write the header
|
577 |
if (lseek(fd, 512, SEEK_SET) < 0) |
578 |
return -EIO;
|
579 |
if (write(fd, buf, 1024) != 1024) |
580 |
return -EIO;
|
581 |
|
582 |
close(fd); |
583 |
return 0; |
584 |
} |
585 |
|
586 |
static void vpc_close(BlockDriverState *bs) |
587 |
{ |
588 |
BDRVVPCState *s = bs->opaque; |
589 |
qemu_free(s->pagetable); |
590 |
#ifdef CACHE
|
591 |
qemu_free(s->pageentry_u8); |
592 |
#endif
|
593 |
bdrv_delete(s->hd); |
594 |
} |
595 |
|
596 |
static QEMUOptionParameter vpc_create_options[] = {
|
597 |
{ |
598 |
.name = BLOCK_OPT_SIZE, |
599 |
.type = OPT_SIZE, |
600 |
.help = "Virtual disk size"
|
601 |
}, |
602 |
{ NULL }
|
603 |
}; |
604 |
|
605 |
static BlockDriver bdrv_vpc = {
|
606 |
.format_name = "vpc",
|
607 |
.instance_size = sizeof(BDRVVPCState),
|
608 |
.bdrv_probe = vpc_probe, |
609 |
.bdrv_open = vpc_open, |
610 |
.bdrv_read = vpc_read, |
611 |
.bdrv_write = vpc_write, |
612 |
.bdrv_close = vpc_close, |
613 |
.bdrv_create = vpc_create, |
614 |
|
615 |
.create_options = vpc_create_options, |
616 |
}; |
617 |
|
618 |
static void bdrv_vpc_init(void) |
619 |
{ |
620 |
bdrv_register(&bdrv_vpc); |
621 |
} |
622 |
|
623 |
block_init(bdrv_vpc_init); |