aboutsummaryrefslogtreecommitdiffstats
path: root/block/vpc.c
diff options
context:
space:
mode:
Diffstat (limited to 'block/vpc.c')
-rw-r--r--block/vpc.c1255
1 files changed, 1255 insertions, 0 deletions
diff --git a/block/vpc.c b/block/vpc.c
new file mode 100644
index 000000000..297a26262
--- /dev/null
+++ b/block/vpc.c
@@ -0,0 +1,1255 @@
+/*
+ * Block driver for Connectix / Microsoft Virtual PC images
+ *
+ * Copyright (c) 2005 Alex Beregszaszi
+ * Copyright (c) 2009 Kevin Wolf <kwolf@suse.de>
+ *
+ * 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/osdep.h"
+#include "qapi/error.h"
+#include "block/block_int.h"
+#include "block/qdict.h"
+#include "sysemu/block-backend.h"
+#include "qemu/module.h"
+#include "qemu/option.h"
+#include "migration/blocker.h"
+#include "qemu/bswap.h"
+#include "qemu/uuid.h"
+#include "qapi/qmp/qdict.h"
+#include "qapi/qobject-input-visitor.h"
+#include "qapi/qapi-visit-block-core.h"
+
+/**************************************************************/
+
+//#define CACHE
+
+enum vhd_type {
+ VHD_FIXED = 2,
+ VHD_DYNAMIC = 3,
+ VHD_DIFFERENCING = 4,
+};
+
+/* Seconds since Jan 1, 2000 0:00:00 (UTC) */
+#define VHD_TIMESTAMP_BASE 946684800
+
+#define VHD_CHS_MAX_C 65535LL
+#define VHD_CHS_MAX_H 16
+#define VHD_CHS_MAX_S 255
+
+#define VHD_MAX_SECTORS 0xff000000 /* 2040 GiB max image size */
+#define VHD_MAX_GEOMETRY (VHD_CHS_MAX_C * VHD_CHS_MAX_H * VHD_CHS_MAX_S)
+
+#define VPC_OPT_FORCE_SIZE "force_size"
+
+/* always big-endian */
+typedef struct vhd_footer {
+ char creator[8]; /* "conectix" */
+ uint32_t features;
+ uint32_t version;
+
+ /* Offset of next header structure, 0xFFFFFFFF if none */
+ uint64_t data_offset;
+
+ /* Seconds since Jan 1, 2000 0:00:00 (UTC) */
+ uint32_t timestamp;
+
+ char creator_app[4]; /* e.g., "vpc " */
+ uint16_t major;
+ uint16_t minor;
+ char creator_os[4]; /* "Wi2k" */
+
+ uint64_t orig_size;
+ uint64_t current_size;
+
+ uint16_t cyls;
+ uint8_t heads;
+ uint8_t secs_per_cyl;
+
+ uint32_t type;
+
+ /* Checksum of the Hard Disk Footer ("one's complement of the sum of all
+ the bytes in the footer without the checksum field") */
+ uint32_t checksum;
+
+ /* UUID used to identify a parent hard disk (backing file) */
+ QemuUUID uuid;
+
+ uint8_t in_saved_state;
+ uint8_t reserved[427];
+} QEMU_PACKED VHDFooter;
+
+QEMU_BUILD_BUG_ON(sizeof(VHDFooter) != 512);
+
+typedef struct vhd_dyndisk_header {
+ char magic[8]; /* "cxsparse" */
+
+ /* Offset of next header structure, 0xFFFFFFFF if none */
+ uint64_t data_offset;
+
+ /* Offset of the Block Allocation Table (BAT) */
+ uint64_t table_offset;
+
+ uint32_t version;
+ uint32_t max_table_entries; /* 32bit/entry */
+
+ /* 2 MB by default, must be a power of two */
+ uint32_t block_size;
+
+ uint32_t checksum;
+ uint8_t parent_uuid[16];
+ uint32_t parent_timestamp;
+ uint32_t reserved;
+
+ /* Backing file name (in UTF-16) */
+ uint8_t parent_name[512];
+
+ struct {
+ uint32_t platform;
+ uint32_t data_space;
+ uint32_t data_length;
+ uint32_t reserved;
+ uint64_t data_offset;
+ } parent_locator[8];
+ uint8_t reserved2[256];
+} QEMU_PACKED VHDDynDiskHeader;
+
+QEMU_BUILD_BUG_ON(sizeof(VHDDynDiskHeader) != 1024);
+
+typedef struct BDRVVPCState {
+ CoMutex lock;
+ VHDFooter footer;
+ uint64_t free_data_block_offset;
+ int max_table_entries;
+ uint32_t *pagetable;
+ uint64_t bat_offset;
+ uint64_t last_bitmap_offset;
+
+ uint32_t block_size;
+ uint32_t bitmap_size;
+ bool force_use_chs;
+ bool force_use_sz;
+
+#ifdef CACHE
+ uint8_t *pageentry_u8;
+ uint32_t *pageentry_u32;
+ uint16_t *pageentry_u16;
+
+ uint64_t last_bitmap;
+#endif
+
+ Error *migration_blocker;
+} BDRVVPCState;
+
+#define VPC_OPT_SIZE_CALC "force_size_calc"
+static QemuOptsList vpc_runtime_opts = {
+ .name = "vpc-runtime-opts",
+ .head = QTAILQ_HEAD_INITIALIZER(vpc_runtime_opts.head),
+ .desc = {
+ {
+ .name = VPC_OPT_SIZE_CALC,
+ .type = QEMU_OPT_STRING,
+ .help = "Force disk size calculation to use either CHS geometry, "
+ "or use the disk current_size specified in the VHD footer. "
+ "{chs, current_size}"
+ },
+ { /* end of list */ }
+ }
+};
+
+static QemuOptsList vpc_create_opts;
+
+static uint32_t vpc_checksum(void *p, size_t size)
+{
+ uint8_t *buf = p;
+ uint32_t res = 0;
+ int i;
+
+ for (i = 0; i < size; i++)
+ res += buf[i];
+
+ return ~res;
+}
+
+
+static int vpc_probe(const uint8_t *buf, int buf_size, const char *filename)
+{
+ if (buf_size >= 8 && !strncmp((char *)buf, "conectix", 8))
+ return 100;
+ return 0;
+}
+
+static void vpc_parse_options(BlockDriverState *bs, QemuOpts *opts,
+ Error **errp)
+{
+ BDRVVPCState *s = bs->opaque;
+ const char *size_calc;
+
+ size_calc = qemu_opt_get(opts, VPC_OPT_SIZE_CALC);
+
+ if (!size_calc) {
+ /* no override, use autodetect only */
+ } else if (!strcmp(size_calc, "current_size")) {
+ s->force_use_sz = true;
+ } else if (!strcmp(size_calc, "chs")) {
+ s->force_use_chs = true;
+ } else {
+ error_setg(errp, "Invalid size calculation mode: '%s'", size_calc);
+ }
+}
+
+static int vpc_open(BlockDriverState *bs, QDict *options, int flags,
+ Error **errp)
+{
+ BDRVVPCState *s = bs->opaque;
+ int i;
+ VHDFooter *footer;
+ QemuOpts *opts = NULL;
+ Error *local_err = NULL;
+ bool use_chs;
+ VHDDynDiskHeader dyndisk_header;
+ uint32_t checksum;
+ uint64_t computed_size;
+ uint64_t pagetable_size;
+ int disk_type = VHD_DYNAMIC;
+ int ret;
+ int64_t bs_size;
+
+ bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
+ BDRV_CHILD_IMAGE, false, errp);
+ if (!bs->file) {
+ return -EINVAL;
+ }
+
+ opts = qemu_opts_create(&vpc_runtime_opts, NULL, 0, &error_abort);
+ if (!qemu_opts_absorb_qdict(opts, options, errp)) {
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ vpc_parse_options(bs, opts, &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ ret = bdrv_pread(bs->file, 0, &s->footer, sizeof(s->footer));
+ if (ret < 0) {
+ error_setg(errp, "Unable to read VHD header");
+ goto fail;
+ }
+
+ footer = &s->footer;
+ if (strncmp(footer->creator, "conectix", 8)) {
+ int64_t offset = bdrv_getlength(bs->file->bs);
+ if (offset < 0) {
+ ret = offset;
+ error_setg(errp, "Invalid file size");
+ goto fail;
+ } else if (offset < sizeof(*footer)) {
+ ret = -EINVAL;
+ error_setg(errp, "File too small for a VHD header");
+ goto fail;
+ }
+
+ /* If a fixed disk, the footer is found only at the end of the file */
+ ret = bdrv_pread(bs->file, offset - sizeof(*footer),
+ footer, sizeof(*footer));
+ if (ret < 0) {
+ goto fail;
+ }
+ if (strncmp(footer->creator, "conectix", 8) ||
+ be32_to_cpu(footer->type) != VHD_FIXED) {
+ error_setg(errp, "invalid VPC image");
+ ret = -EINVAL;
+ goto fail;
+ }
+ disk_type = VHD_FIXED;
+ }
+
+ checksum = be32_to_cpu(footer->checksum);
+ footer->checksum = 0;
+ if (vpc_checksum(footer, sizeof(*footer)) != checksum) {
+ error_setg(errp, "Incorrect header checksum");
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ /* Write 'checksum' back to footer, or else will leave it with zero. */
+ footer->checksum = cpu_to_be32(checksum);
+
+ /* The visible size of a image in Virtual PC depends on the geometry
+ rather than on the size stored in the footer (the size in the footer
+ is too large usually) */
+ bs->total_sectors = (int64_t)
+ be16_to_cpu(footer->cyls) * footer->heads * footer->secs_per_cyl;
+
+ /* Microsoft Virtual PC and Microsoft Hyper-V produce and read
+ * VHD image sizes differently. VPC will rely on CHS geometry,
+ * while Hyper-V and disk2vhd use the size specified in the footer.
+ *
+ * We use a couple of approaches to try and determine the correct method:
+ * look at the Creator App field, and look for images that have CHS
+ * geometry that is the maximum value.
+ *
+ * If the CHS geometry is the maximum CHS geometry, then we assume that
+ * the size is the footer->current_size to avoid truncation. Otherwise,
+ * we follow the table based on footer->creator_app:
+ *
+ * Known creator apps:
+ * 'vpc ' : CHS Virtual PC (uses disk geometry)
+ * 'qemu' : CHS QEMU (uses disk geometry)
+ * 'qem2' : current_size QEMU (uses current_size)
+ * 'win ' : current_size Hyper-V
+ * 'd2v ' : current_size Disk2vhd
+ * 'tap\0' : current_size XenServer
+ * 'CTXS' : current_size XenConverter
+ *
+ * The user can override the table values via drive options, however
+ * even with an override we will still use current_size for images
+ * that have CHS geometry of the maximum size.
+ */
+ use_chs = (!!strncmp(footer->creator_app, "win ", 4) &&
+ !!strncmp(footer->creator_app, "qem2", 4) &&
+ !!strncmp(footer->creator_app, "d2v ", 4) &&
+ !!strncmp(footer->creator_app, "CTXS", 4) &&
+ !!memcmp(footer->creator_app, "tap", 4)) || s->force_use_chs;
+
+ if (!use_chs || bs->total_sectors == VHD_MAX_GEOMETRY || s->force_use_sz) {
+ bs->total_sectors = be64_to_cpu(footer->current_size) /
+ BDRV_SECTOR_SIZE;
+ }
+
+ /* Allow a maximum disk size of 2040 GiB */
+ if (bs->total_sectors > VHD_MAX_SECTORS) {
+ ret = -EFBIG;
+ goto fail;
+ }
+
+ if (disk_type == VHD_DYNAMIC) {
+ ret = bdrv_pread(bs->file, be64_to_cpu(footer->data_offset),
+ &dyndisk_header, sizeof(dyndisk_header));
+ if (ret < 0) {
+ error_setg(errp, "Error reading dynamic VHD header");
+ goto fail;
+ }
+
+ if (strncmp(dyndisk_header.magic, "cxsparse", 8)) {
+ error_setg(errp, "Invalid header magic");
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ s->block_size = be32_to_cpu(dyndisk_header.block_size);
+ if (!is_power_of_2(s->block_size) || s->block_size < BDRV_SECTOR_SIZE) {
+ error_setg(errp, "Invalid block size %" PRIu32, s->block_size);
+ ret = -EINVAL;
+ goto fail;
+ }
+ s->bitmap_size = ((s->block_size / (8 * 512)) + 511) & ~511;
+
+ s->max_table_entries = be32_to_cpu(dyndisk_header.max_table_entries);
+
+ if ((bs->total_sectors * 512) / s->block_size > 0xffffffffU) {
+ error_setg(errp, "Too many blocks");
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ computed_size = (uint64_t) s->max_table_entries * s->block_size;
+ if (computed_size < bs->total_sectors * 512) {
+ error_setg(errp, "Page table too small");
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ if (s->max_table_entries > SIZE_MAX / 4 ||
+ s->max_table_entries > (int) INT_MAX / 4) {
+ error_setg(errp, "Max Table Entries too large (%" PRId32 ")",
+ s->max_table_entries);
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ pagetable_size = (uint64_t) s->max_table_entries * 4;
+
+ s->pagetable = qemu_try_blockalign(bs->file->bs, pagetable_size);
+ if (s->pagetable == NULL) {
+ error_setg(errp, "Unable to allocate memory for page table");
+ ret = -ENOMEM;
+ goto fail;
+ }
+
+ s->bat_offset = be64_to_cpu(dyndisk_header.table_offset);
+
+ ret = bdrv_pread(bs->file, s->bat_offset, s->pagetable,
+ pagetable_size);
+ if (ret < 0) {
+ error_setg(errp, "Error reading pagetable");
+ goto fail;
+ }
+
+ s->free_data_block_offset =
+ ROUND_UP(s->bat_offset + pagetable_size, 512);
+
+ for (i = 0; i < s->max_table_entries; i++) {
+ be32_to_cpus(&s->pagetable[i]);
+ if (s->pagetable[i] != 0xFFFFFFFF) {
+ int64_t next = (512 * (int64_t) s->pagetable[i]) +
+ s->bitmap_size + s->block_size;
+
+ if (next > s->free_data_block_offset) {
+ s->free_data_block_offset = next;
+ }
+ }
+ }
+
+ bs_size = bdrv_getlength(bs->file->bs);
+ if (bs_size < 0) {
+ error_setg_errno(errp, -bs_size, "Unable to learn image size");
+ ret = bs_size;
+ goto fail;
+ }
+ if (s->free_data_block_offset > bs_size) {
+ error_setg(errp, "block-vpc: free_data_block_offset points after "
+ "the end of file. The image has been truncated.");
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ s->last_bitmap_offset = (int64_t) -1;
+
+#ifdef CACHE
+ s->pageentry_u8 = g_malloc(512);
+ s->pageentry_u32 = s->pageentry_u8;
+ s->pageentry_u16 = s->pageentry_u8;
+ s->last_pagetable = -1;
+#endif
+ }
+
+ /* Disable migration when VHD images are used */
+ error_setg(&s->migration_blocker, "The vpc format used by node '%s' "
+ "does not support live migration",
+ bdrv_get_device_or_node_name(bs));
+ ret = migrate_add_blocker(s->migration_blocker, errp);
+ if (ret < 0) {
+ error_free(s->migration_blocker);
+ goto fail;
+ }
+
+ qemu_co_mutex_init(&s->lock);
+ qemu_opts_del(opts);
+
+ return 0;
+
+fail:
+ qemu_opts_del(opts);
+ qemu_vfree(s->pagetable);
+#ifdef CACHE
+ g_free(s->pageentry_u8);
+#endif
+ return ret;
+}
+
+static int vpc_reopen_prepare(BDRVReopenState *state,
+ BlockReopenQueue *queue, Error **errp)
+{
+ return 0;
+}
+
+/*
+ * Returns the absolute byte offset of the given sector in the image file.
+ * If the sector is not allocated, -1 is returned instead.
+ * If an error occurred trying to write an updated block bitmap back to
+ * the file, -2 is returned, and the error value is written to *err.
+ * This can only happen for a write operation.
+ *
+ * The parameter write must be 1 if the offset will be used for a write
+ * operation (the block bitmaps is updated then), 0 otherwise.
+ * If write is true then err must not be NULL.
+ */
+static inline int64_t get_image_offset(BlockDriverState *bs, uint64_t offset,
+ bool write, int *err)
+{
+ BDRVVPCState *s = bs->opaque;
+ uint64_t bitmap_offset, block_offset;
+ uint32_t pagetable_index, offset_in_block;
+
+ assert(!(write && err == NULL));
+
+ pagetable_index = offset / s->block_size;
+ offset_in_block = offset % s->block_size;
+
+ if (pagetable_index >= s->max_table_entries || s->pagetable[pagetable_index] == 0xffffffff)
+ return -1; /* not allocated */
+
+ bitmap_offset = 512 * (uint64_t) s->pagetable[pagetable_index];
+ block_offset = bitmap_offset + s->bitmap_size + offset_in_block;
+
+ /* We must ensure that we don't write to any sectors which are marked as
+ unused in the bitmap. We get away with setting all bits in the block
+ bitmap each time we write to a new block. This might cause Virtual PC to
+ miss sparse read optimization, but it's not a problem in terms of
+ correctness. */
+ if (write && (s->last_bitmap_offset != bitmap_offset)) {
+ uint8_t bitmap[s->bitmap_size];
+ int r;
+
+ s->last_bitmap_offset = bitmap_offset;
+ memset(bitmap, 0xff, s->bitmap_size);
+ r = bdrv_pwrite_sync(bs->file, bitmap_offset, bitmap, s->bitmap_size);
+ if (r < 0) {
+ *err = r;
+ return -2;
+ }
+ }
+
+ return block_offset;
+}
+
+/*
+ * Writes the footer to the end of the image file. This is needed when the
+ * file grows as it overwrites the old footer
+ *
+ * Returns 0 on success and < 0 on error
+ */
+static int rewrite_footer(BlockDriverState *bs)
+{
+ int ret;
+ BDRVVPCState *s = bs->opaque;
+ int64_t offset = s->free_data_block_offset;
+
+ ret = bdrv_pwrite_sync(bs->file, offset, &s->footer, sizeof(s->footer));
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
+
+/*
+ * Allocates a new block. This involves writing a new footer and updating
+ * the Block Allocation Table to use the space at the old end of the image
+ * file (overwriting the old footer)
+ *
+ * Returns the sectors' offset in the image file on success and < 0 on error
+ */
+static int64_t alloc_block(BlockDriverState *bs, int64_t offset)
+{
+ BDRVVPCState *s = bs->opaque;
+ int64_t bat_offset;
+ uint32_t index, bat_value;
+ int ret;
+ uint8_t bitmap[s->bitmap_size];
+
+ /* Check if sector_num is valid */
+ if ((offset < 0) || (offset > bs->total_sectors * BDRV_SECTOR_SIZE)) {
+ return -EINVAL;
+ }
+
+ /* Write entry into in-memory BAT */
+ index = offset / s->block_size;
+ assert(s->pagetable[index] == 0xFFFFFFFF);
+ s->pagetable[index] = s->free_data_block_offset / 512;
+
+ /* Initialize the block's bitmap */
+ memset(bitmap, 0xff, s->bitmap_size);
+ ret = bdrv_pwrite_sync(bs->file, s->free_data_block_offset, bitmap,
+ s->bitmap_size);
+ if (ret < 0) {
+ return ret;
+ }
+
+ /* Write new footer (the old one will be overwritten) */
+ s->free_data_block_offset += s->block_size + s->bitmap_size;
+ ret = rewrite_footer(bs);
+ if (ret < 0)
+ goto fail;
+
+ /* Write BAT entry to disk */
+ bat_offset = s->bat_offset + (4 * index);
+ bat_value = cpu_to_be32(s->pagetable[index]);
+ ret = bdrv_pwrite_sync(bs->file, bat_offset, &bat_value, 4);
+ if (ret < 0)
+ goto fail;
+
+ return get_image_offset(bs, offset, false, NULL);
+
+fail:
+ s->free_data_block_offset -= (s->block_size + s->bitmap_size);
+ return ret;
+}
+
+static int vpc_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
+{
+ BDRVVPCState *s = (BDRVVPCState *)bs->opaque;
+
+ if (be32_to_cpu(s->footer.type) != VHD_FIXED) {
+ bdi->cluster_size = s->block_size;
+ }
+
+ return 0;
+}
+
+static int coroutine_fn
+vpc_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
+ QEMUIOVector *qiov, BdrvRequestFlags flags)
+{
+ BDRVVPCState *s = bs->opaque;
+ int ret;
+ int64_t image_offset;
+ int64_t n_bytes;
+ int64_t bytes_done = 0;
+ QEMUIOVector local_qiov;
+
+ if (be32_to_cpu(s->footer.type) == VHD_FIXED) {
+ return bdrv_co_preadv(bs->file, offset, bytes, qiov, 0);
+ }
+
+ qemu_co_mutex_lock(&s->lock);
+ qemu_iovec_init(&local_qiov, qiov->niov);
+
+ while (bytes > 0) {
+ image_offset = get_image_offset(bs, offset, false, NULL);
+ n_bytes = MIN(bytes, s->block_size - (offset % s->block_size));
+
+ if (image_offset == -1) {
+ qemu_iovec_memset(qiov, bytes_done, 0, n_bytes);
+ } else {
+ qemu_iovec_reset(&local_qiov);
+ qemu_iovec_concat(&local_qiov, qiov, bytes_done, n_bytes);
+
+ qemu_co_mutex_unlock(&s->lock);
+ ret = bdrv_co_preadv(bs->file, image_offset, n_bytes,
+ &local_qiov, 0);
+ qemu_co_mutex_lock(&s->lock);
+ if (ret < 0) {
+ goto fail;
+ }
+ }
+
+ bytes -= n_bytes;
+ offset += n_bytes;
+ bytes_done += n_bytes;
+ }
+
+ ret = 0;
+fail:
+ qemu_iovec_destroy(&local_qiov);
+ qemu_co_mutex_unlock(&s->lock);
+
+ return ret;
+}
+
+static int coroutine_fn
+vpc_co_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes,
+ QEMUIOVector *qiov, BdrvRequestFlags flags)
+{
+ BDRVVPCState *s = bs->opaque;
+ int64_t image_offset;
+ int64_t n_bytes;
+ int64_t bytes_done = 0;
+ int ret = 0;
+ QEMUIOVector local_qiov;
+
+ if (be32_to_cpu(s->footer.type) == VHD_FIXED) {
+ return bdrv_co_pwritev(bs->file, offset, bytes, qiov, 0);
+ }
+
+ qemu_co_mutex_lock(&s->lock);
+ qemu_iovec_init(&local_qiov, qiov->niov);
+
+ while (bytes > 0) {
+ image_offset = get_image_offset(bs, offset, true, &ret);
+ if (image_offset == -2) {
+ /* Failed to write block bitmap: can't proceed with write */
+ goto fail;
+ }
+ n_bytes = MIN(bytes, s->block_size - (offset % s->block_size));
+
+ if (image_offset == -1) {
+ image_offset = alloc_block(bs, offset);
+ if (image_offset < 0) {
+ ret = image_offset;
+ goto fail;
+ }
+ }
+
+ qemu_iovec_reset(&local_qiov);
+ qemu_iovec_concat(&local_qiov, qiov, bytes_done, n_bytes);
+
+ qemu_co_mutex_unlock(&s->lock);
+ ret = bdrv_co_pwritev(bs->file, image_offset, n_bytes,
+ &local_qiov, 0);
+ qemu_co_mutex_lock(&s->lock);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ bytes -= n_bytes;
+ offset += n_bytes;
+ bytes_done += n_bytes;
+ }
+
+ ret = 0;
+fail:
+ qemu_iovec_destroy(&local_qiov);
+ qemu_co_mutex_unlock(&s->lock);
+
+ return ret;
+}
+
+static int coroutine_fn vpc_co_block_status(BlockDriverState *bs,
+ bool want_zero,
+ int64_t offset, int64_t bytes,
+ int64_t *pnum, int64_t *map,
+ BlockDriverState **file)
+{
+ BDRVVPCState *s = bs->opaque;
+ int64_t image_offset;
+ bool allocated;
+ int ret;
+ int64_t n;
+
+ if (be32_to_cpu(s->footer.type) == VHD_FIXED) {
+ *pnum = bytes;
+ *map = offset;
+ *file = bs->file->bs;
+ return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | BDRV_BLOCK_RECURSE;
+ }
+
+ qemu_co_mutex_lock(&s->lock);
+
+ image_offset = get_image_offset(bs, offset, false, NULL);
+ allocated = (image_offset != -1);
+ *pnum = 0;
+ ret = BDRV_BLOCK_ZERO;
+
+ do {
+ /* All sectors in a block are contiguous (without using the bitmap) */
+ n = ROUND_UP(offset + 1, s->block_size) - offset;
+ n = MIN(n, bytes);
+
+ *pnum += n;
+ offset += n;
+ bytes -= n;
+ /* *pnum can't be greater than one block for allocated
+ * sectors since there is always a bitmap in between. */
+ if (allocated) {
+ *file = bs->file->bs;
+ *map = image_offset;
+ ret = BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID;
+ break;
+ }
+ if (bytes == 0) {
+ break;
+ }
+ image_offset = get_image_offset(bs, offset, false, NULL);
+ } while (image_offset == -1);
+
+ qemu_co_mutex_unlock(&s->lock);
+ return ret;
+}
+
+/*
+ * Calculates the number of cylinders, heads and sectors per cylinder
+ * based on a given number of sectors. This is the algorithm described
+ * in the VHD specification.
+ *
+ * Note that the geometry doesn't always exactly match total_sectors but
+ * may round it down.
+ *
+ * Returns 0 on success, -EFBIG if the size is larger than 2040 GiB. Override
+ * the hardware EIDE and ATA-2 limit of 16 heads (max disk size of 127 GB)
+ * and instead allow up to 255 heads.
+ */
+static int calculate_geometry(int64_t total_sectors, uint16_t *cyls,
+ uint8_t *heads, uint8_t *secs_per_cyl)
+{
+ uint32_t cyls_times_heads;
+
+ total_sectors = MIN(total_sectors, VHD_MAX_GEOMETRY);
+
+ if (total_sectors >= 65535LL * 16 * 63) {
+ *secs_per_cyl = 255;
+ *heads = 16;
+ cyls_times_heads = total_sectors / *secs_per_cyl;
+ } else {
+ *secs_per_cyl = 17;
+ cyls_times_heads = total_sectors / *secs_per_cyl;
+ *heads = DIV_ROUND_UP(cyls_times_heads, 1024);
+
+ if (*heads < 4) {
+ *heads = 4;
+ }
+
+ if (cyls_times_heads >= (*heads * 1024) || *heads > 16) {
+ *secs_per_cyl = 31;
+ *heads = 16;
+ cyls_times_heads = total_sectors / *secs_per_cyl;
+ }
+
+ if (cyls_times_heads >= (*heads * 1024)) {
+ *secs_per_cyl = 63;
+ *heads = 16;
+ cyls_times_heads = total_sectors / *secs_per_cyl;
+ }
+ }
+
+ *cyls = cyls_times_heads / *heads;
+
+ return 0;
+}
+
+static int create_dynamic_disk(BlockBackend *blk, VHDFooter *footer,
+ int64_t total_sectors)
+{
+ VHDDynDiskHeader dyndisk_header;
+ uint8_t bat_sector[512];
+ size_t block_size, num_bat_entries;
+ int i;
+ int ret;
+ int64_t offset = 0;
+
+ /* Write the footer (twice: at the beginning and at the end) */
+ block_size = 0x200000;
+ num_bat_entries = DIV_ROUND_UP(total_sectors, block_size / 512);
+
+ ret = blk_pwrite(blk, offset, footer, sizeof(*footer), 0);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ offset = 1536 + ((num_bat_entries * 4 + 511) & ~511);
+ ret = blk_pwrite(blk, offset, footer, sizeof(*footer), 0);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ /* Write the initial BAT */
+ offset = 3 * 512;
+
+ memset(bat_sector, 0xFF, 512);
+ for (i = 0; i < DIV_ROUND_UP(num_bat_entries * 4, 512); i++) {
+ ret = blk_pwrite(blk, offset, bat_sector, 512, 0);
+ if (ret < 0) {
+ goto fail;
+ }
+ offset += 512;
+ }
+
+ /* Prepare the Dynamic Disk Header */
+ memset(&dyndisk_header, 0, sizeof(dyndisk_header));
+
+ memcpy(dyndisk_header.magic, "cxsparse", 8);
+
+ /*
+ * Note: The spec is actually wrong here for data_offset, it says
+ * 0xFFFFFFFF, but MS tools expect all 64 bits to be set.
+ */
+ dyndisk_header.data_offset = cpu_to_be64(0xFFFFFFFFFFFFFFFFULL);
+ dyndisk_header.table_offset = cpu_to_be64(3 * 512);
+ dyndisk_header.version = cpu_to_be32(0x00010000);
+ dyndisk_header.block_size = cpu_to_be32(block_size);
+ dyndisk_header.max_table_entries = cpu_to_be32(num_bat_entries);
+
+ dyndisk_header.checksum = cpu_to_be32(
+ vpc_checksum(&dyndisk_header, sizeof(dyndisk_header)));
+
+ /* Write the header */
+ offset = 512;
+
+ ret = blk_pwrite(blk, offset, &dyndisk_header, sizeof(dyndisk_header), 0);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ ret = 0;
+ fail:
+ return ret;
+}
+
+static int create_fixed_disk(BlockBackend *blk, VHDFooter *footer,
+ int64_t total_size, Error **errp)
+{
+ int ret;
+
+ /* Add footer to total size */
+ total_size += sizeof(*footer);
+
+ ret = blk_truncate(blk, total_size, false, PREALLOC_MODE_OFF, 0, errp);
+ if (ret < 0) {
+ return ret;
+ }
+
+ ret = blk_pwrite(blk, total_size - sizeof(*footer),
+ footer, sizeof(*footer), 0);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "Unable to write VHD header");
+ return ret;
+ }
+
+ return 0;
+}
+
+static int calculate_rounded_image_size(BlockdevCreateOptionsVpc *vpc_opts,
+ uint16_t *out_cyls,
+ uint8_t *out_heads,
+ uint8_t *out_secs_per_cyl,
+ int64_t *out_total_sectors,
+ Error **errp)
+{
+ int64_t total_size = vpc_opts->size;
+ uint16_t cyls = 0;
+ uint8_t heads = 0;
+ uint8_t secs_per_cyl = 0;
+ int64_t total_sectors;
+ int i;
+
+ /*
+ * Calculate matching total_size and geometry. Increase the number of
+ * sectors requested until we get enough (or fail). This ensures that
+ * qemu-img convert doesn't truncate images, but rather rounds up.
+ *
+ * If the image size can't be represented by a spec conformant CHS geometry,
+ * we set the geometry to 65535 x 16 x 255 (CxHxS) sectors and use
+ * the image size from the VHD footer to calculate total_sectors.
+ */
+ if (vpc_opts->force_size) {
+ /* This will force the use of total_size for sector count, below */
+ cyls = VHD_CHS_MAX_C;
+ heads = VHD_CHS_MAX_H;
+ secs_per_cyl = VHD_CHS_MAX_S;
+ } else {
+ total_sectors = MIN(VHD_MAX_GEOMETRY, total_size / BDRV_SECTOR_SIZE);
+ for (i = 0; total_sectors > (int64_t)cyls * heads * secs_per_cyl; i++) {
+ calculate_geometry(total_sectors + i, &cyls, &heads, &secs_per_cyl);
+ }
+ }
+
+ if ((int64_t)cyls * heads * secs_per_cyl == VHD_MAX_GEOMETRY) {
+ total_sectors = total_size / BDRV_SECTOR_SIZE;
+ /* Allow a maximum disk size of 2040 GiB */
+ if (total_sectors > VHD_MAX_SECTORS) {
+ error_setg(errp, "Disk size is too large, max size is 2040 GiB");
+ return -EFBIG;
+ }
+ } else {
+ total_sectors = (int64_t) cyls * heads * secs_per_cyl;
+ }
+
+ *out_total_sectors = total_sectors;
+ if (out_cyls) {
+ *out_cyls = cyls;
+ *out_heads = heads;
+ *out_secs_per_cyl = secs_per_cyl;
+ }
+
+ return 0;
+}
+
+static int coroutine_fn vpc_co_create(BlockdevCreateOptions *opts,
+ Error **errp)
+{
+ BlockdevCreateOptionsVpc *vpc_opts;
+ BlockBackend *blk = NULL;
+ BlockDriverState *bs = NULL;
+
+ VHDFooter footer;
+ uint16_t cyls = 0;
+ uint8_t heads = 0;
+ uint8_t secs_per_cyl = 0;
+ int64_t total_sectors;
+ int64_t total_size;
+ int disk_type;
+ int ret = -EIO;
+ QemuUUID uuid;
+
+ assert(opts->driver == BLOCKDEV_DRIVER_VPC);
+ vpc_opts = &opts->u.vpc;
+
+ /* Validate options and set default values */
+ total_size = vpc_opts->size;
+
+ if (!vpc_opts->has_subformat) {
+ vpc_opts->subformat = BLOCKDEV_VPC_SUBFORMAT_DYNAMIC;
+ }
+ switch (vpc_opts->subformat) {
+ case BLOCKDEV_VPC_SUBFORMAT_DYNAMIC:
+ disk_type = VHD_DYNAMIC;
+ break;
+ case BLOCKDEV_VPC_SUBFORMAT_FIXED:
+ disk_type = VHD_FIXED;
+ break;
+ default:
+ g_assert_not_reached();
+ }
+
+ /* Create BlockBackend to write to the image */
+ bs = bdrv_open_blockdev_ref(vpc_opts->file, errp);
+ if (bs == NULL) {
+ return -EIO;
+ }
+
+ blk = blk_new_with_bs(bs, BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL,
+ errp);
+ if (!blk) {
+ ret = -EPERM;
+ goto out;
+ }
+ blk_set_allow_write_beyond_eof(blk, true);
+
+ /* Get geometry and check that it matches the image size*/
+ ret = calculate_rounded_image_size(vpc_opts, &cyls, &heads, &secs_per_cyl,
+ &total_sectors, errp);
+ if (ret < 0) {
+ goto out;
+ }
+
+ if (total_size != total_sectors * BDRV_SECTOR_SIZE) {
+ error_setg(errp, "The requested image size cannot be represented in "
+ "CHS geometry");
+ error_append_hint(errp, "Try size=%llu or force-size=on (the "
+ "latter makes the image incompatible with "
+ "Virtual PC)",
+ total_sectors * BDRV_SECTOR_SIZE);
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /* Prepare the Hard Disk Footer */
+ memset(&footer, 0, sizeof(footer));
+
+ memcpy(footer.creator, "conectix", 8);
+ if (vpc_opts->force_size) {
+ memcpy(footer.creator_app, "qem2", 4);
+ } else {
+ memcpy(footer.creator_app, "qemu", 4);
+ }
+ memcpy(footer.creator_os, "Wi2k", 4);
+
+ footer.features = cpu_to_be32(0x02);
+ footer.version = cpu_to_be32(0x00010000);
+ if (disk_type == VHD_DYNAMIC) {
+ footer.data_offset = cpu_to_be64(sizeof(footer));
+ } else {
+ footer.data_offset = cpu_to_be64(0xFFFFFFFFFFFFFFFFULL);
+ }
+ footer.timestamp = cpu_to_be32(time(NULL) - VHD_TIMESTAMP_BASE);
+
+ /* Version of Virtual PC 2007 */
+ footer.major = cpu_to_be16(0x0005);
+ footer.minor = cpu_to_be16(0x0003);
+ footer.orig_size = cpu_to_be64(total_size);
+ footer.current_size = cpu_to_be64(total_size);
+ footer.cyls = cpu_to_be16(cyls);
+ footer.heads = heads;
+ footer.secs_per_cyl = secs_per_cyl;
+
+ footer.type = cpu_to_be32(disk_type);
+
+ qemu_uuid_generate(&uuid);
+ footer.uuid = uuid;
+
+ footer.checksum = cpu_to_be32(vpc_checksum(&footer, sizeof(footer)));
+
+ if (disk_type == VHD_DYNAMIC) {
+ ret = create_dynamic_disk(blk, &footer, total_sectors);
+ if (ret < 0) {
+ error_setg(errp, "Unable to create or write VHD header");
+ }
+ } else {
+ ret = create_fixed_disk(blk, &footer, total_size, errp);
+ }
+
+out:
+ blk_unref(blk);
+ bdrv_unref(bs);
+ return ret;
+}
+
+static int coroutine_fn vpc_co_create_opts(BlockDriver *drv,
+ const char *filename,
+ QemuOpts *opts,
+ Error **errp)
+{
+ BlockdevCreateOptions *create_options = NULL;
+ QDict *qdict;
+ Visitor *v;
+ BlockDriverState *bs = NULL;
+ int ret;
+
+ static const QDictRenames opt_renames[] = {
+ { VPC_OPT_FORCE_SIZE, "force-size" },
+ { NULL, NULL },
+ };
+
+ /* Parse options and convert legacy syntax */
+ qdict = qemu_opts_to_qdict_filtered(opts, NULL, &vpc_create_opts, true);
+
+ if (!qdict_rename_keys(qdict, opt_renames, errp)) {
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ /* Create and open the file (protocol layer) */
+ ret = bdrv_create_file(filename, opts, errp);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ bs = bdrv_open(filename, NULL, NULL,
+ BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp);
+ if (bs == NULL) {
+ ret = -EIO;
+ goto fail;
+ }
+
+ /* Now get the QAPI type BlockdevCreateOptions */
+ qdict_put_str(qdict, "driver", "vpc");
+ qdict_put_str(qdict, "file", bs->node_name);
+
+ v = qobject_input_visitor_new_flat_confused(qdict, errp);
+ if (!v) {
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ visit_type_BlockdevCreateOptions(v, NULL, &create_options, errp);
+ visit_free(v);
+ if (!create_options) {
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ /* Silently round up size */
+ assert(create_options->driver == BLOCKDEV_DRIVER_VPC);
+ create_options->u.vpc.size =
+ ROUND_UP(create_options->u.vpc.size, BDRV_SECTOR_SIZE);
+
+ if (!create_options->u.vpc.force_size) {
+ int64_t total_sectors;
+ ret = calculate_rounded_image_size(&create_options->u.vpc, NULL, NULL,
+ NULL, &total_sectors, errp);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ create_options->u.vpc.size = total_sectors * BDRV_SECTOR_SIZE;
+ }
+
+
+ /* Create the vpc image (format layer) */
+ ret = vpc_co_create(create_options, errp);
+
+fail:
+ qobject_unref(qdict);
+ bdrv_unref(bs);
+ qapi_free_BlockdevCreateOptions(create_options);
+ return ret;
+}
+
+
+static int vpc_has_zero_init(BlockDriverState *bs)
+{
+ BDRVVPCState *s = bs->opaque;
+
+ if (be32_to_cpu(s->footer.type) == VHD_FIXED) {
+ return bdrv_has_zero_init(bs->file->bs);
+ } else {
+ return 1;
+ }
+}
+
+static void vpc_close(BlockDriverState *bs)
+{
+ BDRVVPCState *s = bs->opaque;
+ qemu_vfree(s->pagetable);
+#ifdef CACHE
+ g_free(s->pageentry_u8);
+#endif
+
+ migrate_del_blocker(s->migration_blocker);
+ error_free(s->migration_blocker);
+}
+
+static QemuOptsList vpc_create_opts = {
+ .name = "vpc-create-opts",
+ .head = QTAILQ_HEAD_INITIALIZER(vpc_create_opts.head),
+ .desc = {
+ {
+ .name = BLOCK_OPT_SIZE,
+ .type = QEMU_OPT_SIZE,
+ .help = "Virtual disk size"
+ },
+ {
+ .name = BLOCK_OPT_SUBFMT,
+ .type = QEMU_OPT_STRING,
+ .help =
+ "Type of virtual hard disk format. Supported formats are "
+ "{dynamic (default) | fixed} "
+ },
+ {
+ .name = VPC_OPT_FORCE_SIZE,
+ .type = QEMU_OPT_BOOL,
+ .help = "Force disk size calculation to use the actual size "
+ "specified, rather than using the nearest CHS-based "
+ "calculation"
+ },
+ { /* end of list */ }
+ }
+};
+
+static const char *const vpc_strong_runtime_opts[] = {
+ VPC_OPT_SIZE_CALC,
+
+ NULL
+};
+
+static BlockDriver bdrv_vpc = {
+ .format_name = "vpc",
+ .instance_size = sizeof(BDRVVPCState),
+
+ .bdrv_probe = vpc_probe,
+ .bdrv_open = vpc_open,
+ .bdrv_close = vpc_close,
+ .bdrv_reopen_prepare = vpc_reopen_prepare,
+ .bdrv_child_perm = bdrv_default_perms,
+ .bdrv_co_create = vpc_co_create,
+ .bdrv_co_create_opts = vpc_co_create_opts,
+
+ .bdrv_co_preadv = vpc_co_preadv,
+ .bdrv_co_pwritev = vpc_co_pwritev,
+ .bdrv_co_block_status = vpc_co_block_status,
+
+ .bdrv_get_info = vpc_get_info,
+
+ .is_format = true,
+ .create_opts = &vpc_create_opts,
+ .bdrv_has_zero_init = vpc_has_zero_init,
+ .strong_runtime_opts = vpc_strong_runtime_opts,
+};
+
+static void bdrv_vpc_init(void)
+{
+ bdrv_register(&bdrv_vpc);
+}
+
+block_init(bdrv_vpc_init);