--- /dev/null
+/*
+ * Block driver for the various disk image formats used by Bochs
+ * Currently only for "growing" type in read-only mode
+ *
+ * Copyright (c) 2005 Alex Beregszaszi
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#include "qemu-common.h"
+#include "block/block_int.h"
+#include "qemu/module.h"
+
+/**************************************************************/
+
+#define HEADER_MAGIC "Bochs Virtual HD Image"
+#define HEADER_VERSION 0x00020000
+#define HEADER_V1 0x00010000
+#define HEADER_SIZE 512
+
+#define REDOLOG_TYPE "Redolog"
+#define GROWING_TYPE "Growing"
+
+// not allocated: 0xffffffff
+
+// always little-endian
+struct bochs_header {
+ char magic[32]; /* "Bochs Virtual HD Image" */
+ char type[16]; /* "Redolog" */
+ char subtype[16]; /* "Undoable" / "Volatile" / "Growing" */
+ uint32_t version;
+ uint32_t header; /* size of header */
+
+ uint32_t catalog; /* num of entries */
+ uint32_t bitmap; /* bitmap size */
+ uint32_t extent; /* extent size */
+
+ union {
+ struct {
+ uint32_t reserved; /* for ??? */
+ uint64_t disk; /* disk size */
+ char padding[HEADER_SIZE - 64 - 20 - 12];
+ } QEMU_PACKED redolog;
+ struct {
+ uint64_t disk; /* disk size */
+ char padding[HEADER_SIZE - 64 - 20 - 8];
+ } QEMU_PACKED redolog_v1;
+ char padding[HEADER_SIZE - 64 - 20];
+ } extra;
+} QEMU_PACKED;
+
+typedef struct BDRVBochsState {
+ CoMutex lock;
+ uint32_t *catalog_bitmap;
+ uint32_t catalog_size;
+
+ uint32_t data_offset;
+
+ uint32_t bitmap_blocks;
+ uint32_t extent_blocks;
+ uint32_t extent_size;
+} BDRVBochsState;
+
+static int bochs_probe(const uint8_t *buf, int buf_size, const char *filename)
+{
+ const struct bochs_header *bochs = (const void *)buf;
+
+ if (buf_size < HEADER_SIZE)
+ return 0;
+
+ if (!strcmp(bochs->magic, HEADER_MAGIC) &&
+ !strcmp(bochs->type, REDOLOG_TYPE) &&
+ !strcmp(bochs->subtype, GROWING_TYPE) &&
+ ((le32_to_cpu(bochs->version) == HEADER_VERSION) ||
+ (le32_to_cpu(bochs->version) == HEADER_V1)))
+ return 100;
+
+ return 0;
+}
+
+static int bochs_open(BlockDriverState *bs, QDict *options, int flags,
+ Error **errp)
+{
+ BDRVBochsState *s = bs->opaque;
+ uint32_t i;
+ struct bochs_header bochs;
+ int ret;
+
+ bs->read_only = 1; // no write support yet
+
+ ret = bdrv_pread(bs->file, 0, &bochs, sizeof(bochs));
+ if (ret < 0) {
+ return ret;
+ }
+
+ if (strcmp(bochs.magic, HEADER_MAGIC) ||
+ strcmp(bochs.type, REDOLOG_TYPE) ||
+ strcmp(bochs.subtype, GROWING_TYPE) ||
+ ((le32_to_cpu(bochs.version) != HEADER_VERSION) &&
+ (le32_to_cpu(bochs.version) != HEADER_V1))) {
+ error_setg(errp, "Image not in Bochs format");
+ return -EINVAL;
+ }
+
+ if (le32_to_cpu(bochs.version) == HEADER_V1) {
+ bs->total_sectors = le64_to_cpu(bochs.extra.redolog_v1.disk) / 512;
+ } else {
+ bs->total_sectors = le64_to_cpu(bochs.extra.redolog.disk) / 512;
+ }
+
+ /* Limit to 1M entries to avoid unbounded allocation. This is what is
+ * needed for the largest image that bximage can create (~8 TB). */
+ s->catalog_size = le32_to_cpu(bochs.catalog);
+ if (s->catalog_size > 0x100000) {
+ error_setg(errp, "Catalog size is too large");
+ return -EFBIG;
+ }
+
+ s->catalog_bitmap = g_try_new(uint32_t, s->catalog_size);
+ if (s->catalog_size && s->catalog_bitmap == NULL) {
+ error_setg(errp, "Could not allocate memory for catalog");
+ return -ENOMEM;
+ }
+
+ ret = bdrv_pread(bs->file, le32_to_cpu(bochs.header), s->catalog_bitmap,
+ s->catalog_size * 4);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ for (i = 0; i < s->catalog_size; i++)
+ le32_to_cpus(&s->catalog_bitmap[i]);
+
+ s->data_offset = le32_to_cpu(bochs.header) + (s->catalog_size * 4);
+
+ s->bitmap_blocks = 1 + (le32_to_cpu(bochs.bitmap) - 1) / 512;
+ s->extent_blocks = 1 + (le32_to_cpu(bochs.extent) - 1) / 512;
+
+ s->extent_size = le32_to_cpu(bochs.extent);
+ if (s->extent_size < BDRV_SECTOR_SIZE) {
+ /* bximage actually never creates extents smaller than 4k */
+ error_setg(errp, "Extent size must be at least 512");
+ ret = -EINVAL;
+ goto fail;
+ } else if (!is_power_of_2(s->extent_size)) {
+ error_setg(errp, "Extent size %" PRIu32 " is not a power of two",
+ s->extent_size);
+ ret = -EINVAL;
+ goto fail;
+ } else if (s->extent_size > 0x800000) {
+ error_setg(errp, "Extent size %" PRIu32 " is too large",
+ s->extent_size);
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ if (s->catalog_size < DIV_ROUND_UP(bs->total_sectors,
+ s->extent_size / BDRV_SECTOR_SIZE))
+ {
+ error_setg(errp, "Catalog size is too small for this disk size");
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ qemu_co_mutex_init(&s->lock);
+ return 0;
+
+fail:
+ g_free(s->catalog_bitmap);
+ return ret;
+}
+
+static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num)
+{
+ BDRVBochsState *s = bs->opaque;
+ uint64_t offset = sector_num * 512;
+ uint64_t extent_index, extent_offset, bitmap_offset;
+ char bitmap_entry;
+ int ret;
+
+ // seek to sector
+ extent_index = offset / s->extent_size;
+ extent_offset = (offset % s->extent_size) / 512;
+
+ if (s->catalog_bitmap[extent_index] == 0xffffffff) {
+ return 0; /* not allocated */
+ }
+
+ bitmap_offset = s->data_offset +
+ (512 * (uint64_t) s->catalog_bitmap[extent_index] *
+ (s->extent_blocks + s->bitmap_blocks));
+
+ /* read in bitmap for current extent */
+ ret = bdrv_pread(bs->file, bitmap_offset + (extent_offset / 8),
+ &bitmap_entry, 1);
+ if (ret < 0) {
+ return ret;
+ }
+
+ if (!((bitmap_entry >> (extent_offset % 8)) & 1)) {
+ return 0; /* not allocated */
+ }
+
+ return bitmap_offset + (512 * (s->bitmap_blocks + extent_offset));
+}
+
+static int bochs_read(BlockDriverState *bs, int64_t sector_num,
+ uint8_t *buf, int nb_sectors)
+{
+ int ret;
+
+ while (nb_sectors > 0) {
+ int64_t block_offset = seek_to_sector(bs, sector_num);
+ if (block_offset < 0) {
+ return block_offset;
+ } else if (block_offset > 0) {
+ ret = bdrv_pread(bs->file, block_offset, buf, 512);
+ if (ret < 0) {
+ return ret;
+ }
+ } else {
+ memset(buf, 0, 512);
+ }
+ nb_sectors--;
+ sector_num++;
+ buf += 512;
+ }
+ return 0;
+}
+
+static coroutine_fn int bochs_co_read(BlockDriverState *bs, int64_t sector_num,
+ uint8_t *buf, int nb_sectors)
+{
+ int ret;
+ BDRVBochsState *s = bs->opaque;
+ qemu_co_mutex_lock(&s->lock);
+ ret = bochs_read(bs, sector_num, buf, nb_sectors);
+ qemu_co_mutex_unlock(&s->lock);
+ return ret;
+}
+
+static void bochs_close(BlockDriverState *bs)
+{
+ BDRVBochsState *s = bs->opaque;
+ g_free(s->catalog_bitmap);
+}
+
+static BlockDriver bdrv_bochs = {
+ .format_name = "bochs",
+ .instance_size = sizeof(BDRVBochsState),
+ .bdrv_probe = bochs_probe,
+ .bdrv_open = bochs_open,
+ .bdrv_read = bochs_co_read,
+ .bdrv_close = bochs_close,
+};
+
+static void bdrv_bochs_init(void)
+{
+ bdrv_register(&bdrv_bochs);
+}
+
+block_init(bdrv_bochs_init);
Code Review / kvmfornfv.git / blobdiff