root / block-vpc.c @ f97572e5
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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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*
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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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/**************************************************************/
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#define HEADER_SIZE 512 |
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//#define CACHE
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// always big-endian
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struct vpc_subheader {
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char magic[8]; // "conectix" / "cxsparse" |
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union {
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struct {
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uint32_t unk1[2];
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uint32_t unk2; // always zero?
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uint32_t subheader_offset; |
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uint32_t unk3; // some size?
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char creator[4]; // "vpc " |
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uint16_t major; |
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uint16_t minor; |
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char guest[4]; // "Wi2k" |
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uint32_t unk4[7];
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uint8_t vnet_id[16]; // virtual network id, purpose unknown |
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// next 16 longs are used, but dunno the purpose
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// next 6 longs unknown, following 7 long maybe a serial
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char padding[HEADER_SIZE - 84]; |
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} main; |
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struct {
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uint32_t unk1[2]; // all bits set |
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uint32_t unk2; // always zero?
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uint32_t pagetable_offset; |
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uint32_t unk3; |
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uint32_t pagetable_entries; // 32bit/entry
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uint32_t pageentry_size; // 512*8*512
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uint32_t nb_sectors; |
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char padding[HEADER_SIZE - 40]; |
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} sparse; |
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char padding[HEADER_SIZE - 8]; |
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} type; |
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}; |
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typedef struct BDRVVPCState { |
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int fd;
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int pagetable_entries;
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uint32_t *pagetable; |
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uint32_t pageentry_size; |
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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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uint64_t last_bitmap; |
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#endif
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} BDRVVPCState; |
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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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} |
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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 fd, i;
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struct vpc_subheader header;
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fd = open(filename, O_RDONLY | O_BINARY); |
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if (fd < 0) |
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return -1; |
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bs->read_only = 1; // no write support yet |
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s->fd = fd; |
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if (read(fd, &header, HEADER_SIZE) != HEADER_SIZE)
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goto fail;
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if (strncmp(header.magic, "conectix", 8)) |
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goto fail;
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lseek(s->fd, be32_to_cpu(header.type.main.subheader_offset), SEEK_SET); |
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if (read(fd, &header, HEADER_SIZE) != HEADER_SIZE)
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goto fail;
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if (strncmp(header.magic, "cxsparse", 8)) |
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goto fail;
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bs->total_sectors = ((uint64_t)be32_to_cpu(header.type.sparse.pagetable_entries) * |
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be32_to_cpu(header.type.sparse.pageentry_size)) / 512;
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lseek(s->fd, be32_to_cpu(header.type.sparse.pagetable_offset), SEEK_SET); |
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s->pagetable_entries = be32_to_cpu(header.type.sparse.pagetable_entries); |
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s->pagetable = qemu_malloc(s->pagetable_entries * 4);
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if (!s->pagetable)
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goto fail;
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if (read(s->fd, s->pagetable, s->pagetable_entries * 4) != |
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s->pagetable_entries * 4)
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goto fail;
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for (i = 0; i < s->pagetable_entries; i++) |
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be32_to_cpus(&s->pagetable[i]); |
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s->pageentry_size = be32_to_cpu(header.type.sparse.pageentry_size); |
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#ifdef CACHE
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s->pageentry_u8 = qemu_malloc(512);
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if (!s->pageentry_u8)
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goto fail;
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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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close(fd); |
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return -1; |
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} |
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static inline int seek_to_sector(BlockDriverState *bs, int64_t sector_num) |
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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; |
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pagetable_index = offset / s->pageentry_size; |
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pageentry_index = (offset % s->pageentry_size) / 512;
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if (pagetable_index > s->pagetable_entries || s->pagetable[pagetable_index] == 0xffffffff) |
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return -1; // not allocated |
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bitmap_offset = 512 * s->pagetable[pagetable_index];
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block_offset = bitmap_offset + 512 + (512 * pageentry_index); |
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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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// disabled by reason
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#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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s->last_bitmap = bitmap_offset;
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// Scary! Bitmap is stored as big endian 32bit entries,
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// while we used to look it up byte by byte
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read(s->fd, s->pageentry_u8, 512);
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for (i = 0; i < 128; i++)
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be32_to_cpus(&s->pageentry_u32[i]);
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}
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if ((s->pageentry_u8[pageentry_index / 8] >> (pageentry_index % 8)) & 1)
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return -1;
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#else
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lseek(s->fd, bitmap_offset + (pageentry_index / 8), SEEK_SET);
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read(s->fd, &bitmap_entry, 1);
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if ((bitmap_entry >> (pageentry_index % 8)) & 1) |
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return -1; // not allocated |
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#endif
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#endif
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lseek(s->fd, block_offset, SEEK_SET); |
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return 0; |
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} |
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static int vpc_read(BlockDriverState *bs, int64_t sector_num, |
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uint8_t *buf, int nb_sectors)
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{ |
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BDRVVPCState *s = bs->opaque; |
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int ret;
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while (nb_sectors > 0) { |
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if (!seek_to_sector(bs, sector_num))
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{ |
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ret = read(s->fd, buf, 512);
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if (ret != 512) |
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return -1; |
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} |
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else
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memset(buf, 0, 512); |
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nb_sectors--; |
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sector_num++; |
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buf += 512;
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} |
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return 0; |
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} |
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static void vpc_close(BlockDriverState *bs) |
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{ |
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BDRVVPCState *s = bs->opaque; |
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qemu_free(s->pagetable); |
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#ifdef CACHE
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qemu_free(s->pageentry_u8); |
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#endif
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close(s->fd); |
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} |
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BlockDriver bdrv_vpc = { |
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"vpc",
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sizeof(BDRVVPCState),
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vpc_probe, |
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vpc_open, |
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vpc_read, |
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NULL,
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vpc_close, |
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}; |