313 lines
9.2 KiB
C
313 lines
9.2 KiB
C
/*
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* Block driver for the various disk image formats used by Bochs
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* Currently only for "growing" type in read-only mode
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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/osdep.h"
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#include "qapi/error.h"
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#include "qemu-common.h"
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#include "block/block_int.h"
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#include "qemu/module.h"
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#include "qemu/bswap.h"
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#include "qemu/error-report.h"
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/**************************************************************/
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#define HEADER_MAGIC "Bochs Virtual HD Image"
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#define HEADER_VERSION 0x00020000
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#define HEADER_V1 0x00010000
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#define HEADER_SIZE 512
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#define REDOLOG_TYPE "Redolog"
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#define GROWING_TYPE "Growing"
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// not allocated: 0xffffffff
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// always little-endian
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struct bochs_header {
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char magic[32]; /* "Bochs Virtual HD Image" */
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char type[16]; /* "Redolog" */
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char subtype[16]; /* "Undoable" / "Volatile" / "Growing" */
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uint32_t version;
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uint32_t header; /* size of header */
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uint32_t catalog; /* num of entries */
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uint32_t bitmap; /* bitmap size */
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uint32_t extent; /* extent size */
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union {
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struct {
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uint32_t reserved; /* for ??? */
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uint64_t disk; /* disk size */
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char padding[HEADER_SIZE - 64 - 20 - 12];
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} QEMU_PACKED redolog;
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struct {
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uint64_t disk; /* disk size */
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char padding[HEADER_SIZE - 64 - 20 - 8];
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} QEMU_PACKED redolog_v1;
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char padding[HEADER_SIZE - 64 - 20];
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} extra;
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} QEMU_PACKED;
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typedef struct BDRVBochsState {
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CoMutex lock;
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uint32_t *catalog_bitmap;
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uint32_t catalog_size;
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uint32_t data_offset;
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uint32_t bitmap_blocks;
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uint32_t extent_blocks;
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uint32_t extent_size;
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} BDRVBochsState;
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static int bochs_probe(const uint8_t *buf, int buf_size, const char *filename)
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{
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const struct bochs_header *bochs = (const void *)buf;
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if (buf_size < HEADER_SIZE)
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return 0;
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if (!strcmp(bochs->magic, HEADER_MAGIC) &&
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!strcmp(bochs->type, REDOLOG_TYPE) &&
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!strcmp(bochs->subtype, GROWING_TYPE) &&
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((le32_to_cpu(bochs->version) == HEADER_VERSION) ||
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(le32_to_cpu(bochs->version) == HEADER_V1)))
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return 100;
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return 0;
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}
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static int bochs_open(BlockDriverState *bs, QDict *options, int flags,
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Error **errp)
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{
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BDRVBochsState *s = bs->opaque;
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uint32_t i;
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struct bochs_header bochs;
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int ret;
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/* No write support yet */
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ret = bdrv_apply_auto_read_only(bs, NULL, errp);
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if (ret < 0) {
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return ret;
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}
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bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
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false, errp);
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if (!bs->file) {
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return -EINVAL;
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}
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ret = bdrv_pread(bs->file, 0, &bochs, sizeof(bochs));
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if (ret < 0) {
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return ret;
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}
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if (strcmp(bochs.magic, HEADER_MAGIC) ||
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strcmp(bochs.type, REDOLOG_TYPE) ||
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strcmp(bochs.subtype, GROWING_TYPE) ||
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((le32_to_cpu(bochs.version) != HEADER_VERSION) &&
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(le32_to_cpu(bochs.version) != HEADER_V1))) {
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error_setg(errp, "Image not in Bochs format");
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return -EINVAL;
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}
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if (le32_to_cpu(bochs.version) == HEADER_V1) {
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bs->total_sectors = le64_to_cpu(bochs.extra.redolog_v1.disk) / 512;
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} else {
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bs->total_sectors = le64_to_cpu(bochs.extra.redolog.disk) / 512;
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}
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/* Limit to 1M entries to avoid unbounded allocation. This is what is
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* needed for the largest image that bximage can create (~8 TB). */
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s->catalog_size = le32_to_cpu(bochs.catalog);
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if (s->catalog_size > 0x100000) {
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error_setg(errp, "Catalog size is too large");
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return -EFBIG;
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}
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s->catalog_bitmap = g_try_new(uint32_t, s->catalog_size);
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if (s->catalog_size && s->catalog_bitmap == NULL) {
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error_setg(errp, "Could not allocate memory for catalog");
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return -ENOMEM;
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}
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ret = bdrv_pread(bs->file, le32_to_cpu(bochs.header), s->catalog_bitmap,
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s->catalog_size * 4);
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if (ret < 0) {
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goto fail;
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}
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for (i = 0; i < s->catalog_size; i++)
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le32_to_cpus(&s->catalog_bitmap[i]);
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s->data_offset = le32_to_cpu(bochs.header) + (s->catalog_size * 4);
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s->bitmap_blocks = 1 + (le32_to_cpu(bochs.bitmap) - 1) / 512;
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s->extent_blocks = 1 + (le32_to_cpu(bochs.extent) - 1) / 512;
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s->extent_size = le32_to_cpu(bochs.extent);
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if (s->extent_size < BDRV_SECTOR_SIZE) {
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/* bximage actually never creates extents smaller than 4k */
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error_setg(errp, "Extent size must be at least 512");
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ret = -EINVAL;
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goto fail;
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} else if (!is_power_of_2(s->extent_size)) {
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error_setg(errp, "Extent size %" PRIu32 " is not a power of two",
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s->extent_size);
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ret = -EINVAL;
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goto fail;
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} else if (s->extent_size > 0x800000) {
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error_setg(errp, "Extent size %" PRIu32 " is too large",
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s->extent_size);
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ret = -EINVAL;
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goto fail;
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}
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if (s->catalog_size < DIV_ROUND_UP(bs->total_sectors,
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s->extent_size / BDRV_SECTOR_SIZE))
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{
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error_setg(errp, "Catalog size is too small for this disk size");
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ret = -EINVAL;
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goto fail;
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}
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qemu_co_mutex_init(&s->lock);
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return 0;
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fail:
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g_free(s->catalog_bitmap);
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return ret;
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}
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static void bochs_refresh_limits(BlockDriverState *bs, Error **errp)
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{
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bs->bl.request_alignment = BDRV_SECTOR_SIZE; /* No sub-sector I/O */
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}
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static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num)
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{
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BDRVBochsState *s = bs->opaque;
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uint64_t offset = sector_num * 512;
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uint64_t extent_index, extent_offset, bitmap_offset;
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char bitmap_entry;
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int ret;
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// seek to sector
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extent_index = offset / s->extent_size;
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extent_offset = (offset % s->extent_size) / 512;
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if (s->catalog_bitmap[extent_index] == 0xffffffff) {
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return 0; /* not allocated */
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}
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bitmap_offset = s->data_offset +
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(512 * (uint64_t) s->catalog_bitmap[extent_index] *
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(s->extent_blocks + s->bitmap_blocks));
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/* read in bitmap for current extent */
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ret = bdrv_pread(bs->file, bitmap_offset + (extent_offset / 8),
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&bitmap_entry, 1);
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if (ret < 0) {
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return ret;
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}
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if (!((bitmap_entry >> (extent_offset % 8)) & 1)) {
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return 0; /* not allocated */
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}
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return bitmap_offset + (512 * (s->bitmap_blocks + extent_offset));
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}
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static int coroutine_fn
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bochs_co_preadv(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
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QEMUIOVector *qiov, int flags)
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{
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BDRVBochsState *s = bs->opaque;
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uint64_t sector_num = offset >> BDRV_SECTOR_BITS;
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int nb_sectors = bytes >> BDRV_SECTOR_BITS;
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uint64_t bytes_done = 0;
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QEMUIOVector local_qiov;
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int ret;
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assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0);
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assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0);
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qemu_iovec_init(&local_qiov, qiov->niov);
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qemu_co_mutex_lock(&s->lock);
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while (nb_sectors > 0) {
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int64_t block_offset = seek_to_sector(bs, sector_num);
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if (block_offset < 0) {
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ret = block_offset;
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goto fail;
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}
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qemu_iovec_reset(&local_qiov);
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qemu_iovec_concat(&local_qiov, qiov, bytes_done, 512);
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if (block_offset > 0) {
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ret = bdrv_co_preadv(bs->file, block_offset, 512,
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&local_qiov, 0);
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if (ret < 0) {
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goto fail;
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}
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} else {
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qemu_iovec_memset(&local_qiov, 0, 0, 512);
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}
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nb_sectors--;
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sector_num++;
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bytes_done += 512;
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}
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ret = 0;
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fail:
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qemu_co_mutex_unlock(&s->lock);
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qemu_iovec_destroy(&local_qiov);
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return ret;
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}
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static void bochs_close(BlockDriverState *bs)
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{
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BDRVBochsState *s = bs->opaque;
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g_free(s->catalog_bitmap);
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}
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static BlockDriver bdrv_bochs = {
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.format_name = "bochs",
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.instance_size = sizeof(BDRVBochsState),
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.bdrv_probe = bochs_probe,
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.bdrv_open = bochs_open,
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.bdrv_child_perm = bdrv_format_default_perms,
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.bdrv_refresh_limits = bochs_refresh_limits,
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.bdrv_co_preadv = bochs_co_preadv,
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.bdrv_close = bochs_close,
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};
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static void bdrv_bochs_init(void)
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{
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bdrv_register(&bdrv_bochs);
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}
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block_init(bdrv_bochs_init);
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