qemu/block/vhdx.c
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   1/*
   2 * Block driver for Hyper-V VHDX Images
   3 *
   4 * Copyright (c) 2013 Red Hat, Inc.,
   5 *
   6 * Authors:
   7 *  Jeff Cody <jcody@redhat.com>
   8 *
   9 *  This is based on the "VHDX Format Specification v1.00", published 8/25/2012
  10 *  by Microsoft:
  11 *      https://www.microsoft.com/en-us/download/details.aspx?id=34750
  12 *
  13 * This work is licensed under the terms of the GNU LGPL, version 2 or later.
  14 * See the COPYING.LIB file in the top-level directory.
  15 *
  16 */
  17
  18#include "qemu/osdep.h"
  19#include "qapi/error.h"
  20#include "block/block_int.h"
  21#include "block/qdict.h"
  22#include "sysemu/block-backend.h"
  23#include "qemu/module.h"
  24#include "qemu/option.h"
  25#include "qemu/crc32c.h"
  26#include "qemu/bswap.h"
  27#include "qemu/error-report.h"
  28#include "vhdx.h"
  29#include "migration/blocker.h"
  30#include "qemu/uuid.h"
  31#include "qapi/qmp/qdict.h"
  32#include "qapi/qobject-input-visitor.h"
  33#include "qapi/qapi-visit-block-core.h"
  34
  35/* Options for VHDX creation */
  36
  37#define VHDX_BLOCK_OPT_LOG_SIZE   "log_size"
  38#define VHDX_BLOCK_OPT_BLOCK_SIZE "block_size"
  39#define VHDX_BLOCK_OPT_ZERO "block_state_zero"
  40
  41typedef enum VHDXImageType {
  42    VHDX_TYPE_DYNAMIC = 0,
  43    VHDX_TYPE_FIXED,
  44    VHDX_TYPE_DIFFERENCING,   /* Currently unsupported */
  45} VHDXImageType;
  46
  47static QemuOptsList vhdx_create_opts;
  48
  49/* Several metadata and region table data entries are identified by
  50 * guids in  a MS-specific GUID format. */
  51
  52
  53/* ------- Known Region Table GUIDs ---------------------- */
  54static const MSGUID bat_guid =      { .data1 = 0x2dc27766,
  55                                      .data2 = 0xf623,
  56                                      .data3 = 0x4200,
  57                                      .data4 = { 0x9d, 0x64, 0x11, 0x5e,
  58                                                 0x9b, 0xfd, 0x4a, 0x08} };
  59
  60static const MSGUID metadata_guid = { .data1 = 0x8b7ca206,
  61                                      .data2 = 0x4790,
  62                                      .data3 = 0x4b9a,
  63                                      .data4 = { 0xb8, 0xfe, 0x57, 0x5f,
  64                                                 0x05, 0x0f, 0x88, 0x6e} };
  65
  66
  67
  68/* ------- Known Metadata Entry GUIDs ---------------------- */
  69static const MSGUID file_param_guid =   { .data1 = 0xcaa16737,
  70                                          .data2 = 0xfa36,
  71                                          .data3 = 0x4d43,
  72                                          .data4 = { 0xb3, 0xb6, 0x33, 0xf0,
  73                                                     0xaa, 0x44, 0xe7, 0x6b} };
  74
  75static const MSGUID virtual_size_guid = { .data1 = 0x2FA54224,
  76                                          .data2 = 0xcd1b,
  77                                          .data3 = 0x4876,
  78                                          .data4 = { 0xb2, 0x11, 0x5d, 0xbe,
  79                                                     0xd8, 0x3b, 0xf4, 0xb8} };
  80
  81static const MSGUID page83_guid =       { .data1 = 0xbeca12ab,
  82                                          .data2 = 0xb2e6,
  83                                          .data3 = 0x4523,
  84                                          .data4 = { 0x93, 0xef, 0xc3, 0x09,
  85                                                     0xe0, 0x00, 0xc7, 0x46} };
  86
  87
  88static const MSGUID phys_sector_guid =  { .data1 = 0xcda348c7,
  89                                          .data2 = 0x445d,
  90                                          .data3 = 0x4471,
  91                                          .data4 = { 0x9c, 0xc9, 0xe9, 0x88,
  92                                                     0x52, 0x51, 0xc5, 0x56} };
  93
  94static const MSGUID parent_locator_guid = { .data1 = 0xa8d35f2d,
  95                                            .data2 = 0xb30b,
  96                                            .data3 = 0x454d,
  97                                            .data4 = { 0xab, 0xf7, 0xd3,
  98                                                       0xd8, 0x48, 0x34,
  99                                                       0xab, 0x0c} };
 100
 101static const MSGUID logical_sector_guid = { .data1 = 0x8141bf1d,
 102                                            .data2 = 0xa96f,
 103                                            .data3 = 0x4709,
 104                                            .data4 = { 0xba, 0x47, 0xf2,
 105                                                       0x33, 0xa8, 0xfa,
 106                                                       0xab, 0x5f} };
 107
 108/* Each parent type must have a valid GUID; this is for parent images
 109 * of type 'VHDX'.  If we were to allow e.g. a QCOW2 parent, we would
 110 * need to make up our own QCOW2 GUID type */
 111static const MSGUID parent_vhdx_guid __attribute__((unused))
 112                                     = { .data1 = 0xb04aefb7,
 113                                         .data2 = 0xd19e,
 114                                         .data3 = 0x4a81,
 115                                         .data4 = { 0xb7, 0x89, 0x25, 0xb8,
 116                                                    0xe9, 0x44, 0x59, 0x13} };
 117
 118
 119#define META_FILE_PARAMETER_PRESENT      0x01
 120#define META_VIRTUAL_DISK_SIZE_PRESENT   0x02
 121#define META_PAGE_83_PRESENT             0x04
 122#define META_LOGICAL_SECTOR_SIZE_PRESENT 0x08
 123#define META_PHYS_SECTOR_SIZE_PRESENT    0x10
 124#define META_PARENT_LOCATOR_PRESENT      0x20
 125
 126#define META_ALL_PRESENT    \
 127    (META_FILE_PARAMETER_PRESENT | META_VIRTUAL_DISK_SIZE_PRESENT | \
 128     META_PAGE_83_PRESENT | META_LOGICAL_SECTOR_SIZE_PRESENT | \
 129     META_PHYS_SECTOR_SIZE_PRESENT)
 130
 131
 132typedef struct VHDXSectorInfo {
 133    uint32_t bat_idx;       /* BAT entry index */
 134    uint32_t sectors_avail; /* sectors available in payload block */
 135    uint32_t bytes_left;    /* bytes left in the block after data to r/w */
 136    uint32_t bytes_avail;   /* bytes available in payload block */
 137    uint64_t file_offset;   /* absolute offset in bytes, in file */
 138    uint64_t block_offset;  /* block offset, in bytes */
 139} VHDXSectorInfo;
 140
 141/* Calculates new checksum.
 142 *
 143 * Zero is substituted during crc calculation for the original crc field
 144 * crc_offset: byte offset in buf of the buffer crc
 145 * buf: buffer pointer
 146 * size: size of buffer (must be > crc_offset+4)
 147 *
 148 * Note: The buffer should have all multi-byte data in little-endian format,
 149 *       and the resulting checksum is in little endian format.
 150 */
 151uint32_t vhdx_update_checksum(uint8_t *buf, size_t size, int crc_offset)
 152{
 153    uint32_t crc;
 154
 155    assert(buf != NULL);
 156    assert(size > (crc_offset + sizeof(crc)));
 157
 158    memset(buf + crc_offset, 0, sizeof(crc));
 159    crc =  crc32c(0xffffffff, buf, size);
 160    crc = cpu_to_le32(crc);
 161    memcpy(buf + crc_offset, &crc, sizeof(crc));
 162
 163    return crc;
 164}
 165
 166uint32_t vhdx_checksum_calc(uint32_t crc, uint8_t *buf, size_t size,
 167                            int crc_offset)
 168{
 169    uint32_t crc_new;
 170    uint32_t crc_orig;
 171    assert(buf != NULL);
 172
 173    if (crc_offset > 0) {
 174        memcpy(&crc_orig, buf + crc_offset, sizeof(crc_orig));
 175        memset(buf + crc_offset, 0, sizeof(crc_orig));
 176    }
 177
 178    crc_new = crc32c(crc, buf, size);
 179    if (crc_offset > 0) {
 180        memcpy(buf + crc_offset, &crc_orig, sizeof(crc_orig));
 181    }
 182
 183    return crc_new;
 184}
 185
 186/* Validates the checksum of the buffer, with an in-place CRC.
 187 *
 188 * Zero is substituted during crc calculation for the original crc field,
 189 * and the crc field is restored afterwards.  But the buffer will be modified
 190 * during the calculation, so this may not be not suitable for multi-threaded
 191 * use.
 192 *
 193 * crc_offset: byte offset in buf of the buffer crc
 194 * buf: buffer pointer
 195 * size: size of buffer (must be > crc_offset+4)
 196 *
 197 * returns true if checksum is valid, false otherwise
 198 */
 199bool vhdx_checksum_is_valid(uint8_t *buf, size_t size, int crc_offset)
 200{
 201    uint32_t crc_orig;
 202    uint32_t crc;
 203
 204    assert(buf != NULL);
 205    assert(size > (crc_offset + 4));
 206
 207    memcpy(&crc_orig, buf + crc_offset, sizeof(crc_orig));
 208    crc_orig = le32_to_cpu(crc_orig);
 209
 210    crc = vhdx_checksum_calc(0xffffffff, buf, size, crc_offset);
 211
 212    return crc == crc_orig;
 213}
 214
 215
 216/*
 217 * This generates a UUID that is compliant with the MS GUIDs used
 218 * in the VHDX spec (and elsewhere).
 219 */
 220void vhdx_guid_generate(MSGUID *guid)
 221{
 222    QemuUUID uuid;
 223    assert(guid != NULL);
 224
 225    qemu_uuid_generate(&uuid);
 226    memcpy(guid, &uuid, sizeof(MSGUID));
 227}
 228
 229/* Check for region overlaps inside the VHDX image */
 230static int vhdx_region_check(BDRVVHDXState *s, uint64_t start, uint64_t length)
 231{
 232    int ret = 0;
 233    uint64_t end;
 234    VHDXRegionEntry *r;
 235
 236    end = start + length;
 237    QLIST_FOREACH(r, &s->regions, entries) {
 238        if (!((start >= r->end) || (end <= r->start))) {
 239            error_report("VHDX region %" PRIu64 "-%" PRIu64 " overlaps with "
 240                         "region %" PRIu64 "-%." PRIu64, start, end, r->start,
 241                         r->end);
 242            ret = -EINVAL;
 243            goto exit;
 244        }
 245    }
 246
 247exit:
 248    return ret;
 249}
 250
 251/* Register a region for future checks */
 252static void vhdx_region_register(BDRVVHDXState *s,
 253                                 uint64_t start, uint64_t length)
 254{
 255    VHDXRegionEntry *r;
 256
 257    r = g_malloc0(sizeof(*r));
 258
 259    r->start = start;
 260    r->end = start + length;
 261
 262    QLIST_INSERT_HEAD(&s->regions, r, entries);
 263}
 264
 265/* Free all registered regions */
 266static void vhdx_region_unregister_all(BDRVVHDXState *s)
 267{
 268    VHDXRegionEntry *r, *r_next;
 269
 270    QLIST_FOREACH_SAFE(r, &s->regions, entries, r_next) {
 271        QLIST_REMOVE(r, entries);
 272        g_free(r);
 273    }
 274}
 275
 276static void vhdx_set_shift_bits(BDRVVHDXState *s)
 277{
 278    s->logical_sector_size_bits = ctz32(s->logical_sector_size);
 279    s->sectors_per_block_bits =   ctz32(s->sectors_per_block);
 280    s->chunk_ratio_bits =         ctz64(s->chunk_ratio);
 281    s->block_size_bits =          ctz32(s->block_size);
 282}
 283
 284/*
 285 * Per the MS VHDX Specification, for every VHDX file:
 286 *      - The header section is fixed size - 1 MB
 287 *      - The header section is always the first "object"
 288 *      - The first 64KB of the header is the File Identifier
 289 *      - The first uint64 (8 bytes) is the VHDX Signature ("vhdxfile")
 290 *      - The following 512 bytes constitute a UTF-16 string identifiying the
 291 *        software that created the file, and is optional and diagnostic only.
 292 *
 293 *  Therefore, we probe by looking for the vhdxfile signature "vhdxfile"
 294 */
 295static int vhdx_probe(const uint8_t *buf, int buf_size, const char *filename)
 296{
 297    if (buf_size >= 8 && !memcmp(buf, "vhdxfile", 8)) {
 298        return 100;
 299    }
 300    return 0;
 301}
 302
 303/*
 304 * Writes the header to the specified offset.
 305 *
 306 * This will optionally read in buffer data from disk (otherwise zero-fill),
 307 * and then update the header checksum.  Header is converted to proper
 308 * endianness before being written to the specified file offset
 309 */
 310static int vhdx_write_header(BdrvChild *file, VHDXHeader *hdr,
 311                             uint64_t offset, bool read)
 312{
 313    BlockDriverState *bs_file = file->bs;
 314    uint8_t *buffer = NULL;
 315    int ret;
 316    VHDXHeader *header_le;
 317
 318    assert(bs_file != NULL);
 319    assert(hdr != NULL);
 320
 321    /* the header checksum is not over just the packed size of VHDXHeader,
 322     * but rather over the entire 'reserved' range for the header, which is
 323     * 4KB (VHDX_HEADER_SIZE). */
 324
 325    buffer = qemu_blockalign(bs_file, VHDX_HEADER_SIZE);
 326    if (read) {
 327        /* if true, we can't assume the extra reserved bytes are 0 */
 328        ret = bdrv_pread(file, offset, buffer, VHDX_HEADER_SIZE);
 329        if (ret < 0) {
 330            goto exit;
 331        }
 332    } else {
 333        memset(buffer, 0, VHDX_HEADER_SIZE);
 334    }
 335
 336    /* overwrite the actual VHDXHeader portion */
 337    header_le = (VHDXHeader *)buffer;
 338    memcpy(header_le, hdr, sizeof(VHDXHeader));
 339    vhdx_header_le_export(hdr, header_le);
 340    vhdx_update_checksum(buffer, VHDX_HEADER_SIZE,
 341                         offsetof(VHDXHeader, checksum));
 342    ret = bdrv_pwrite_sync(file, offset, header_le, sizeof(VHDXHeader));
 343
 344exit:
 345    qemu_vfree(buffer);
 346    return ret;
 347}
 348
 349/* Update the VHDX headers
 350 *
 351 * This follows the VHDX spec procedures for header updates.
 352 *
 353 *  - non-current header is updated with largest sequence number
 354 */
 355static int vhdx_update_header(BlockDriverState *bs, BDRVVHDXState *s,
 356                              bool generate_data_write_guid, MSGUID *log_guid)
 357{
 358    int ret = 0;
 359    int hdr_idx = 0;
 360    uint64_t header_offset = VHDX_HEADER1_OFFSET;
 361
 362    VHDXHeader *active_header;
 363    VHDXHeader *inactive_header;
 364
 365    /* operate on the non-current header */
 366    if (s->curr_header == 0) {
 367        hdr_idx = 1;
 368        header_offset = VHDX_HEADER2_OFFSET;
 369    }
 370
 371    active_header   = s->headers[s->curr_header];
 372    inactive_header = s->headers[hdr_idx];
 373
 374    inactive_header->sequence_number = active_header->sequence_number + 1;
 375
 376    /* a new file guid must be generated before any file write, including
 377     * headers */
 378    inactive_header->file_write_guid = s->session_guid;
 379
 380    /* a new data guid only needs to be generated before any guest-visible
 381     * writes (i.e. something observable via virtual disk read) */
 382    if (generate_data_write_guid) {
 383        vhdx_guid_generate(&inactive_header->data_write_guid);
 384    }
 385
 386    /* update the log guid if present */
 387    if (log_guid) {
 388        inactive_header->log_guid = *log_guid;
 389    }
 390
 391    ret = vhdx_write_header(bs->file, inactive_header, header_offset, true);
 392    if (ret < 0) {
 393        goto exit;
 394    }
 395    s->curr_header = hdr_idx;
 396
 397exit:
 398    return ret;
 399}
 400
 401/*
 402 * The VHDX spec calls for header updates to be performed twice, so that both
 403 * the current and non-current header have valid info
 404 */
 405int vhdx_update_headers(BlockDriverState *bs, BDRVVHDXState *s,
 406                        bool generate_data_write_guid, MSGUID *log_guid)
 407{
 408    int ret;
 409
 410    ret = vhdx_update_header(bs, s, generate_data_write_guid, log_guid);
 411    if (ret < 0) {
 412        return ret;
 413    }
 414    ret = vhdx_update_header(bs, s, generate_data_write_guid, log_guid);
 415    return ret;
 416}
 417
 418/* opens the specified header block from the VHDX file header section */
 419static void vhdx_parse_header(BlockDriverState *bs, BDRVVHDXState *s,
 420                              Error **errp)
 421{
 422    int ret;
 423    VHDXHeader *header1;
 424    VHDXHeader *header2;
 425    bool h1_valid = false;
 426    bool h2_valid = false;
 427    uint64_t h1_seq = 0;
 428    uint64_t h2_seq = 0;
 429    uint8_t *buffer;
 430
 431    /* header1 & header2 are freed in vhdx_close() */
 432    header1 = qemu_blockalign(bs, sizeof(VHDXHeader));
 433    header2 = qemu_blockalign(bs, sizeof(VHDXHeader));
 434
 435    buffer = qemu_blockalign(bs, VHDX_HEADER_SIZE);
 436
 437    s->headers[0] = header1;
 438    s->headers[1] = header2;
 439
 440    /* We have to read the whole VHDX_HEADER_SIZE instead of
 441     * sizeof(VHDXHeader), because the checksum is over the whole
 442     * region */
 443    ret = bdrv_pread(bs->file, VHDX_HEADER1_OFFSET, buffer,
 444                     VHDX_HEADER_SIZE);
 445    if (ret < 0) {
 446        goto fail;
 447    }
 448    /* copy over just the relevant portion that we need */
 449    memcpy(header1, buffer, sizeof(VHDXHeader));
 450
 451    if (vhdx_checksum_is_valid(buffer, VHDX_HEADER_SIZE, 4)) {
 452        vhdx_header_le_import(header1);
 453        if (header1->signature == VHDX_HEADER_SIGNATURE &&
 454            header1->version == 1) {
 455            h1_seq = header1->sequence_number;
 456            h1_valid = true;
 457        }
 458    }
 459
 460    ret = bdrv_pread(bs->file, VHDX_HEADER2_OFFSET, buffer,
 461                     VHDX_HEADER_SIZE);
 462    if (ret < 0) {
 463        goto fail;
 464    }
 465    /* copy over just the relevant portion that we need */
 466    memcpy(header2, buffer, sizeof(VHDXHeader));
 467
 468    if (vhdx_checksum_is_valid(buffer, VHDX_HEADER_SIZE, 4)) {
 469        vhdx_header_le_import(header2);
 470        if (header2->signature == VHDX_HEADER_SIGNATURE &&
 471            header2->version == 1) {
 472            h2_seq = header2->sequence_number;
 473            h2_valid = true;
 474        }
 475    }
 476
 477    /* If there is only 1 valid header (or no valid headers), we
 478     * don't care what the sequence numbers are */
 479    if (h1_valid && !h2_valid) {
 480        s->curr_header = 0;
 481    } else if (!h1_valid && h2_valid) {
 482        s->curr_header = 1;
 483    } else if (!h1_valid && !h2_valid) {
 484        goto fail;
 485    } else {
 486        /* If both headers are valid, then we choose the active one by the
 487         * highest sequence number.  If the sequence numbers are equal, that is
 488         * invalid */
 489        if (h1_seq > h2_seq) {
 490            s->curr_header = 0;
 491        } else if (h2_seq > h1_seq) {
 492            s->curr_header = 1;
 493        } else {
 494            /* The Microsoft Disk2VHD tool will create 2 identical
 495             * headers, with identical sequence numbers.  If the headers are
 496             * identical, don't consider the file corrupt */
 497            if (!memcmp(header1, header2, sizeof(VHDXHeader))) {
 498                s->curr_header = 0;
 499            } else {
 500                goto fail;
 501            }
 502        }
 503    }
 504
 505    vhdx_region_register(s, s->headers[s->curr_header]->log_offset,
 506                            s->headers[s->curr_header]->log_length);
 507    goto exit;
 508
 509fail:
 510    error_setg_errno(errp, -ret, "No valid VHDX header found");
 511    qemu_vfree(header1);
 512    qemu_vfree(header2);
 513    s->headers[0] = NULL;
 514    s->headers[1] = NULL;
 515exit:
 516    qemu_vfree(buffer);
 517}
 518
 519
 520static int vhdx_open_region_tables(BlockDriverState *bs, BDRVVHDXState *s)
 521{
 522    int ret = 0;
 523    uint8_t *buffer;
 524    int offset = 0;
 525    VHDXRegionTableEntry rt_entry;
 526    uint32_t i;
 527    bool bat_rt_found = false;
 528    bool metadata_rt_found = false;
 529
 530    /* We have to read the whole 64KB block, because the crc32 is over the
 531     * whole block */
 532    buffer = qemu_blockalign(bs, VHDX_HEADER_BLOCK_SIZE);
 533
 534    ret = bdrv_pread(bs->file, VHDX_REGION_TABLE_OFFSET, buffer,
 535                     VHDX_HEADER_BLOCK_SIZE);
 536    if (ret < 0) {
 537        goto fail;
 538    }
 539    memcpy(&s->rt, buffer, sizeof(s->rt));
 540    offset += sizeof(s->rt);
 541
 542    if (!vhdx_checksum_is_valid(buffer, VHDX_HEADER_BLOCK_SIZE, 4)) {
 543        ret = -EINVAL;
 544        goto fail;
 545    }
 546
 547    vhdx_region_header_le_import(&s->rt);
 548
 549    if (s->rt.signature != VHDX_REGION_SIGNATURE) {
 550        ret = -EINVAL;
 551        goto fail;
 552    }
 553
 554
 555    /* Per spec, maximum region table entry count is 2047 */
 556    if (s->rt.entry_count > 2047) {
 557        ret = -EINVAL;
 558        goto fail;
 559    }
 560
 561    for (i = 0; i < s->rt.entry_count; i++) {
 562        memcpy(&rt_entry, buffer + offset, sizeof(rt_entry));
 563        offset += sizeof(rt_entry);
 564
 565        vhdx_region_entry_le_import(&rt_entry);
 566
 567        /* check for region overlap between these entries, and any
 568         * other memory regions in the file */
 569        ret = vhdx_region_check(s, rt_entry.file_offset, rt_entry.length);
 570        if (ret < 0) {
 571            goto fail;
 572        }
 573
 574        vhdx_region_register(s, rt_entry.file_offset, rt_entry.length);
 575
 576        /* see if we recognize the entry */
 577        if (guid_eq(rt_entry.guid, bat_guid)) {
 578            /* must be unique; if we have already found it this is invalid */
 579            if (bat_rt_found) {
 580                ret = -EINVAL;
 581                goto fail;
 582            }
 583            bat_rt_found = true;
 584            s->bat_rt = rt_entry;
 585            continue;
 586        }
 587
 588        if (guid_eq(rt_entry.guid, metadata_guid)) {
 589            /* must be unique; if we have already found it this is invalid */
 590            if (metadata_rt_found) {
 591                ret = -EINVAL;
 592                goto fail;
 593            }
 594            metadata_rt_found = true;
 595            s->metadata_rt = rt_entry;
 596            continue;
 597        }
 598
 599        if (rt_entry.data_bits & VHDX_REGION_ENTRY_REQUIRED) {
 600            /* cannot read vhdx file - required region table entry that
 601             * we do not understand.  per spec, we must fail to open */
 602            ret = -ENOTSUP;
 603            goto fail;
 604        }
 605    }
 606
 607    if (!bat_rt_found || !metadata_rt_found) {
 608        ret = -EINVAL;
 609        goto fail;
 610    }
 611
 612    ret = 0;
 613
 614fail:
 615    qemu_vfree(buffer);
 616    return ret;
 617}
 618
 619
 620
 621/* Metadata initial parser
 622 *
 623 * This loads all the metadata entry fields.  This may cause additional
 624 * fields to be processed (e.g. parent locator, etc..).
 625 *
 626 * There are 5 Metadata items that are always required:
 627 *      - File Parameters (block size, has a parent)
 628 *      - Virtual Disk Size (size, in bytes, of the virtual drive)
 629 *      - Page 83 Data (scsi page 83 guid)
 630 *      - Logical Sector Size (logical sector size in bytes, either 512 or
 631 *                             4096.  We only support 512 currently)
 632 *      - Physical Sector Size (512 or 4096)
 633 *
 634 * Also, if the File Parameters indicate this is a differencing file,
 635 * we must also look for the Parent Locator metadata item.
 636 */
 637static int vhdx_parse_metadata(BlockDriverState *bs, BDRVVHDXState *s)
 638{
 639    int ret = 0;
 640    uint8_t *buffer;
 641    int offset = 0;
 642    uint32_t i = 0;
 643    VHDXMetadataTableEntry md_entry;
 644
 645    buffer = qemu_blockalign(bs, VHDX_METADATA_TABLE_MAX_SIZE);
 646
 647    ret = bdrv_pread(bs->file, s->metadata_rt.file_offset, buffer,
 648                     VHDX_METADATA_TABLE_MAX_SIZE);
 649    if (ret < 0) {
 650        goto exit;
 651    }
 652    memcpy(&s->metadata_hdr, buffer, sizeof(s->metadata_hdr));
 653    offset += sizeof(s->metadata_hdr);
 654
 655    vhdx_metadata_header_le_import(&s->metadata_hdr);
 656
 657    if (s->metadata_hdr.signature != VHDX_METADATA_SIGNATURE) {
 658        ret = -EINVAL;
 659        goto exit;
 660    }
 661
 662    s->metadata_entries.present = 0;
 663
 664    if ((s->metadata_hdr.entry_count * sizeof(md_entry)) >
 665        (VHDX_METADATA_TABLE_MAX_SIZE - offset)) {
 666        ret = -EINVAL;
 667        goto exit;
 668    }
 669
 670    for (i = 0; i < s->metadata_hdr.entry_count; i++) {
 671        memcpy(&md_entry, buffer + offset, sizeof(md_entry));
 672        offset += sizeof(md_entry);
 673
 674        vhdx_metadata_entry_le_import(&md_entry);
 675
 676        if (guid_eq(md_entry.item_id, file_param_guid)) {
 677            if (s->metadata_entries.present & META_FILE_PARAMETER_PRESENT) {
 678                ret = -EINVAL;
 679                goto exit;
 680            }
 681            s->metadata_entries.file_parameters_entry = md_entry;
 682            s->metadata_entries.present |= META_FILE_PARAMETER_PRESENT;
 683            continue;
 684        }
 685
 686        if (guid_eq(md_entry.item_id, virtual_size_guid)) {
 687            if (s->metadata_entries.present & META_VIRTUAL_DISK_SIZE_PRESENT) {
 688                ret = -EINVAL;
 689                goto exit;
 690            }
 691            s->metadata_entries.virtual_disk_size_entry = md_entry;
 692            s->metadata_entries.present |= META_VIRTUAL_DISK_SIZE_PRESENT;
 693            continue;
 694        }
 695
 696        if (guid_eq(md_entry.item_id, page83_guid)) {
 697            if (s->metadata_entries.present & META_PAGE_83_PRESENT) {
 698                ret = -EINVAL;
 699                goto exit;
 700            }
 701            s->metadata_entries.page83_data_entry = md_entry;
 702            s->metadata_entries.present |= META_PAGE_83_PRESENT;
 703            continue;
 704        }
 705
 706        if (guid_eq(md_entry.item_id, logical_sector_guid)) {
 707            if (s->metadata_entries.present &
 708                META_LOGICAL_SECTOR_SIZE_PRESENT) {
 709                ret = -EINVAL;
 710                goto exit;
 711            }
 712            s->metadata_entries.logical_sector_size_entry = md_entry;
 713            s->metadata_entries.present |= META_LOGICAL_SECTOR_SIZE_PRESENT;
 714            continue;
 715        }
 716
 717        if (guid_eq(md_entry.item_id, phys_sector_guid)) {
 718            if (s->metadata_entries.present & META_PHYS_SECTOR_SIZE_PRESENT) {
 719                ret = -EINVAL;
 720                goto exit;
 721            }
 722            s->metadata_entries.phys_sector_size_entry = md_entry;
 723            s->metadata_entries.present |= META_PHYS_SECTOR_SIZE_PRESENT;
 724            continue;
 725        }
 726
 727        if (guid_eq(md_entry.item_id, parent_locator_guid)) {
 728            if (s->metadata_entries.present & META_PARENT_LOCATOR_PRESENT) {
 729                ret = -EINVAL;
 730                goto exit;
 731            }
 732            s->metadata_entries.parent_locator_entry = md_entry;
 733            s->metadata_entries.present |= META_PARENT_LOCATOR_PRESENT;
 734            continue;
 735        }
 736
 737        if (md_entry.data_bits & VHDX_META_FLAGS_IS_REQUIRED) {
 738            /* cannot read vhdx file - required region table entry that
 739             * we do not understand.  per spec, we must fail to open */
 740            ret = -ENOTSUP;
 741            goto exit;
 742        }
 743    }
 744
 745    if (s->metadata_entries.present != META_ALL_PRESENT) {
 746        ret = -ENOTSUP;
 747        goto exit;
 748    }
 749
 750    ret = bdrv_pread(bs->file,
 751                     s->metadata_entries.file_parameters_entry.offset
 752                                         + s->metadata_rt.file_offset,
 753                     &s->params,
 754                     sizeof(s->params));
 755
 756    if (ret < 0) {
 757        goto exit;
 758    }
 759
 760    s->params.block_size = le32_to_cpu(s->params.block_size);
 761    s->params.data_bits = le32_to_cpu(s->params.data_bits);
 762
 763
 764    /* We now have the file parameters, so we can tell if this is a
 765     * differencing file (i.e.. has_parent), is dynamic or fixed
 766     * sized (leave_blocks_allocated), and the block size */
 767
 768    /* The parent locator required iff the file parameters has_parent set */
 769    if (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) {
 770        if (s->metadata_entries.present & META_PARENT_LOCATOR_PRESENT) {
 771            /* TODO: parse  parent locator fields */
 772            ret = -ENOTSUP; /* temp, until differencing files are supported */
 773            goto exit;
 774        } else {
 775            /* if has_parent is set, but there is not parent locator present,
 776             * then that is an invalid combination */
 777            ret = -EINVAL;
 778            goto exit;
 779        }
 780    }
 781
 782    /* determine virtual disk size, logical sector size,
 783     * and phys sector size */
 784
 785    ret = bdrv_pread(bs->file,
 786                     s->metadata_entries.virtual_disk_size_entry.offset
 787                                           + s->metadata_rt.file_offset,
 788                     &s->virtual_disk_size,
 789                     sizeof(uint64_t));
 790    if (ret < 0) {
 791        goto exit;
 792    }
 793    ret = bdrv_pread(bs->file,
 794                     s->metadata_entries.logical_sector_size_entry.offset
 795                                             + s->metadata_rt.file_offset,
 796                     &s->logical_sector_size,
 797                     sizeof(uint32_t));
 798    if (ret < 0) {
 799        goto exit;
 800    }
 801    ret = bdrv_pread(bs->file,
 802                     s->metadata_entries.phys_sector_size_entry.offset
 803                                          + s->metadata_rt.file_offset,
 804                     &s->physical_sector_size,
 805                     sizeof(uint32_t));
 806    if (ret < 0) {
 807        goto exit;
 808    }
 809
 810    s->virtual_disk_size = le64_to_cpu(s->virtual_disk_size);
 811    s->logical_sector_size = le32_to_cpu(s->logical_sector_size);
 812    s->physical_sector_size = le32_to_cpu(s->physical_sector_size);
 813
 814    if (s->params.block_size < VHDX_BLOCK_SIZE_MIN ||
 815        s->params.block_size > VHDX_BLOCK_SIZE_MAX) {
 816        ret = -EINVAL;
 817        goto exit;
 818    }
 819
 820    /* only 2 supported sector sizes */
 821    if (s->logical_sector_size != 512 && s->logical_sector_size != 4096) {
 822        ret = -EINVAL;
 823        goto exit;
 824    }
 825
 826    /* Both block_size and sector_size are guaranteed powers of 2, below.
 827       Due to range checks above, s->sectors_per_block can never be < 256 */
 828    s->sectors_per_block = s->params.block_size / s->logical_sector_size;
 829    s->chunk_ratio = (VHDX_MAX_SECTORS_PER_BLOCK) *
 830                     (uint64_t)s->logical_sector_size /
 831                     (uint64_t)s->params.block_size;
 832
 833    /* These values are ones we will want to use for division / multiplication
 834     * later on, and they are all guaranteed (per the spec) to be powers of 2,
 835     * so we can take advantage of that for shift operations during
 836     * reads/writes */
 837    if (s->logical_sector_size & (s->logical_sector_size - 1)) {
 838        ret = -EINVAL;
 839        goto exit;
 840    }
 841    if (s->sectors_per_block & (s->sectors_per_block - 1)) {
 842        ret = -EINVAL;
 843        goto exit;
 844    }
 845    if (s->chunk_ratio & (s->chunk_ratio - 1)) {
 846        ret = -EINVAL;
 847        goto exit;
 848    }
 849    s->block_size = s->params.block_size;
 850    if (s->block_size & (s->block_size - 1)) {
 851        ret = -EINVAL;
 852        goto exit;
 853    }
 854
 855    vhdx_set_shift_bits(s);
 856
 857    ret = 0;
 858
 859exit:
 860    qemu_vfree(buffer);
 861    return ret;
 862}
 863
 864/*
 865 * Calculate the number of BAT entries, including sector
 866 * bitmap entries.
 867 */
 868static void vhdx_calc_bat_entries(BDRVVHDXState *s)
 869{
 870    uint32_t data_blocks_cnt, bitmap_blocks_cnt;
 871
 872    data_blocks_cnt = DIV_ROUND_UP(s->virtual_disk_size, s->block_size);
 873    bitmap_blocks_cnt = DIV_ROUND_UP(data_blocks_cnt, s->chunk_ratio);
 874
 875    if (s->parent_entries) {
 876        s->bat_entries = bitmap_blocks_cnt * (s->chunk_ratio + 1);
 877    } else {
 878        s->bat_entries = data_blocks_cnt +
 879                         ((data_blocks_cnt - 1) >> s->chunk_ratio_bits);
 880    }
 881
 882}
 883
 884static int vhdx_check_bat_entries(BlockDriverState *bs, int *errcnt)
 885{
 886    BDRVVHDXState *s = bs->opaque;
 887    int64_t image_file_size = bdrv_getlength(bs->file->bs);
 888    uint64_t payblocks = s->chunk_ratio;
 889    uint64_t i;
 890    int ret = 0;
 891
 892    if (image_file_size < 0) {
 893        error_report("Could not determinate VHDX image file size.");
 894        return image_file_size;
 895    }
 896
 897    for (i = 0; i < s->bat_entries; i++) {
 898        if ((s->bat[i] & VHDX_BAT_STATE_BIT_MASK) ==
 899            PAYLOAD_BLOCK_FULLY_PRESENT) {
 900            uint64_t offset = s->bat[i] & VHDX_BAT_FILE_OFF_MASK;
 901            /*
 902             * Allow that the last block exists only partially. The VHDX spec
 903             * states that the image file can only grow in blocksize increments,
 904             * but QEMU created images with partial last blocks in the past.
 905             */
 906            uint32_t block_length = MIN(s->block_size,
 907                bs->total_sectors * BDRV_SECTOR_SIZE - i * s->block_size);
 908            /*
 909             * Check for BAT entry overflow.
 910             */
 911            if (offset > INT64_MAX - s->block_size) {
 912                error_report("VHDX BAT entry %" PRIu64 " offset overflow.", i);
 913                ret = -EINVAL;
 914                if (!errcnt) {
 915                    break;
 916                }
 917                (*errcnt)++;
 918            }
 919            /*
 920             * Check if fully allocated BAT entries do not reside after
 921             * end of the image file.
 922             */
 923            if (offset >= image_file_size) {
 924                error_report("VHDX BAT entry %" PRIu64 " start offset %" PRIu64
 925                             " points after end of file (%" PRIi64 "). Image"
 926                             " has probably been truncated.",
 927                             i, offset, image_file_size);
 928                ret = -EINVAL;
 929                if (!errcnt) {
 930                    break;
 931                }
 932                (*errcnt)++;
 933            } else if (offset + block_length > image_file_size) {
 934                error_report("VHDX BAT entry %" PRIu64 " end offset %" PRIu64
 935                             " points after end of file (%" PRIi64 "). Image"
 936                             " has probably been truncated.",
 937                             i, offset + block_length - 1, image_file_size);
 938                ret = -EINVAL;
 939                if (!errcnt) {
 940                    break;
 941                }
 942                (*errcnt)++;
 943            }
 944
 945            /*
 946             * verify populated BAT field file offsets against
 947             * region table and log entries
 948             */
 949            if (payblocks--) {
 950                /* payload bat entries */
 951                int ret2;
 952                ret2 = vhdx_region_check(s, offset, s->block_size);
 953                if (ret2 < 0) {
 954                    ret = -EINVAL;
 955                    if (!errcnt) {
 956                        break;
 957                    }
 958                    (*errcnt)++;
 959                }
 960            } else {
 961                payblocks = s->chunk_ratio;
 962                /*
 963                 * Once differencing files are supported, verify sector bitmap
 964                 * blocks here
 965                 */
 966            }
 967        }
 968    }
 969
 970    return ret;
 971}
 972
 973static void vhdx_close(BlockDriverState *bs)
 974{
 975    BDRVVHDXState *s = bs->opaque;
 976    qemu_vfree(s->headers[0]);
 977    s->headers[0] = NULL;
 978    qemu_vfree(s->headers[1]);
 979    s->headers[1] = NULL;
 980    qemu_vfree(s->bat);
 981    s->bat = NULL;
 982    qemu_vfree(s->parent_entries);
 983    s->parent_entries = NULL;
 984    migrate_del_blocker(s->migration_blocker);
 985    error_free(s->migration_blocker);
 986    qemu_vfree(s->log.hdr);
 987    s->log.hdr = NULL;
 988    vhdx_region_unregister_all(s);
 989}
 990
 991static int vhdx_open(BlockDriverState *bs, QDict *options, int flags,
 992                     Error **errp)
 993{
 994    BDRVVHDXState *s = bs->opaque;
 995    int ret = 0;
 996    uint32_t i;
 997    uint64_t signature;
 998    Error *local_err = NULL;
 999
1000    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
1001                               false, errp);
1002    if (!bs->file) {
1003        return -EINVAL;
1004    }
1005
1006    s->bat = NULL;
1007    s->first_visible_write = true;
1008
1009    qemu_co_mutex_init(&s->lock);
1010    QLIST_INIT(&s->regions);
1011
1012    /* validate the file signature */
1013    ret = bdrv_pread(bs->file, 0, &signature, sizeof(uint64_t));
1014    if (ret < 0) {
1015        goto fail;
1016    }
1017    if (memcmp(&signature, "vhdxfile", 8)) {
1018        ret = -EINVAL;
1019        goto fail;
1020    }
1021
1022    /* This is used for any header updates, for the file_write_guid.
1023     * The spec dictates that a new value should be used for the first
1024     * header update */
1025    vhdx_guid_generate(&s->session_guid);
1026
1027    vhdx_parse_header(bs, s, &local_err);
1028    if (local_err != NULL) {
1029        error_propagate(errp, local_err);
1030        ret = -EINVAL;
1031        goto fail;
1032    }
1033
1034    ret = vhdx_parse_log(bs, s, &s->log_replayed_on_open, errp);
1035    if (ret < 0) {
1036        goto fail;
1037    }
1038
1039    ret = vhdx_open_region_tables(bs, s);
1040    if (ret < 0) {
1041        goto fail;
1042    }
1043
1044    ret = vhdx_parse_metadata(bs, s);
1045    if (ret < 0) {
1046        goto fail;
1047    }
1048
1049    s->block_size = s->params.block_size;
1050
1051    /* the VHDX spec dictates that virtual_disk_size is always a multiple of
1052     * logical_sector_size */
1053    bs->total_sectors = s->virtual_disk_size >> s->logical_sector_size_bits;
1054
1055    vhdx_calc_bat_entries(s);
1056
1057    s->bat_offset = s->bat_rt.file_offset;
1058
1059    if (s->bat_entries > s->bat_rt.length / sizeof(VHDXBatEntry)) {
1060        /* BAT allocation is not large enough for all entries */
1061        ret = -EINVAL;
1062        goto fail;
1063    }
1064
1065    /* s->bat is freed in vhdx_close() */
1066    s->bat = qemu_try_blockalign(bs->file->bs, s->bat_rt.length);
1067    if (s->bat == NULL) {
1068        ret = -ENOMEM;
1069        goto fail;
1070    }
1071
1072    ret = bdrv_pread(bs->file, s->bat_offset, s->bat, s->bat_rt.length);
1073    if (ret < 0) {
1074        goto fail;
1075    }
1076
1077    /* endian convert populated BAT field entires */
1078    for (i = 0; i < s->bat_entries; i++) {
1079        s->bat[i] = le64_to_cpu(s->bat[i]);
1080    }
1081
1082    if (!(flags & BDRV_O_CHECK)) {
1083        ret = vhdx_check_bat_entries(bs, NULL);
1084        if (ret < 0) {
1085            goto fail;
1086        }
1087    }
1088
1089    /* Disable migration when VHDX images are used */
1090    error_setg(&s->migration_blocker, "The vhdx format used by node '%s' "
1091               "does not support live migration",
1092               bdrv_get_device_or_node_name(bs));
1093    ret = migrate_add_blocker(s->migration_blocker, &local_err);
1094    if (local_err) {
1095        error_propagate(errp, local_err);
1096        error_free(s->migration_blocker);
1097        goto fail;
1098    }
1099
1100    /* TODO: differencing files */
1101
1102    return 0;
1103fail:
1104    vhdx_close(bs);
1105    return ret;
1106}
1107
1108static int vhdx_reopen_prepare(BDRVReopenState *state,
1109                               BlockReopenQueue *queue, Error **errp)
1110{
1111    return 0;
1112}
1113
1114
1115/*
1116 * Perform sector to block offset translations, to get various
1117 * sector and file offsets into the image.  See VHDXSectorInfo
1118 */
1119static void vhdx_block_translate(BDRVVHDXState *s, int64_t sector_num,
1120                                 int nb_sectors, VHDXSectorInfo *sinfo)
1121{
1122    uint32_t block_offset;
1123
1124    sinfo->bat_idx = sector_num >> s->sectors_per_block_bits;
1125    /* effectively a modulo - this gives us the offset into the block
1126     * (in sector sizes) for our sector number */
1127    block_offset = sector_num - (sinfo->bat_idx << s->sectors_per_block_bits);
1128    /* the chunk ratio gives us the interleaving of the sector
1129     * bitmaps, so we need to advance our page block index by the
1130     * sector bitmaps entry number */
1131    sinfo->bat_idx += sinfo->bat_idx >> s->chunk_ratio_bits;
1132
1133    /* the number of sectors we can read/write in this cycle */
1134    sinfo->sectors_avail = s->sectors_per_block - block_offset;
1135
1136    sinfo->bytes_left = sinfo->sectors_avail << s->logical_sector_size_bits;
1137
1138    if (sinfo->sectors_avail > nb_sectors) {
1139        sinfo->sectors_avail = nb_sectors;
1140    }
1141
1142    sinfo->bytes_avail = sinfo->sectors_avail << s->logical_sector_size_bits;
1143
1144    sinfo->file_offset = s->bat[sinfo->bat_idx] & VHDX_BAT_FILE_OFF_MASK;
1145
1146    sinfo->block_offset = block_offset << s->logical_sector_size_bits;
1147
1148    /* The file offset must be past the header section, so must be > 0 */
1149    if (sinfo->file_offset == 0) {
1150        return;
1151    }
1152
1153    /* block offset is the offset in vhdx logical sectors, in
1154     * the payload data block. Convert that to a byte offset
1155     * in the block, and add in the payload data block offset
1156     * in the file, in bytes, to get the final read address */
1157
1158    sinfo->file_offset += sinfo->block_offset;
1159}
1160
1161
1162static int vhdx_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
1163{
1164    BDRVVHDXState *s = bs->opaque;
1165
1166    bdi->cluster_size = s->block_size;
1167
1168    bdi->unallocated_blocks_are_zero =
1169        (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) == 0;
1170
1171    return 0;
1172}
1173
1174
1175static coroutine_fn int vhdx_co_readv(BlockDriverState *bs, int64_t sector_num,
1176                                      int nb_sectors, QEMUIOVector *qiov)
1177{
1178    BDRVVHDXState *s = bs->opaque;
1179    int ret = 0;
1180    VHDXSectorInfo sinfo;
1181    uint64_t bytes_done = 0;
1182    QEMUIOVector hd_qiov;
1183
1184    qemu_iovec_init(&hd_qiov, qiov->niov);
1185
1186    qemu_co_mutex_lock(&s->lock);
1187
1188    while (nb_sectors > 0) {
1189        /* We are a differencing file, so we need to inspect the sector bitmap
1190         * to see if we have the data or not */
1191        if (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) {
1192            /* not supported yet */
1193            ret = -ENOTSUP;
1194            goto exit;
1195        } else {
1196            vhdx_block_translate(s, sector_num, nb_sectors, &sinfo);
1197
1198            qemu_iovec_reset(&hd_qiov);
1199            qemu_iovec_concat(&hd_qiov, qiov,  bytes_done, sinfo.bytes_avail);
1200
1201            /* check the payload block state */
1202            switch (s->bat[sinfo.bat_idx] & VHDX_BAT_STATE_BIT_MASK) {
1203            case PAYLOAD_BLOCK_NOT_PRESENT: /* fall through */
1204            case PAYLOAD_BLOCK_UNDEFINED:
1205            case PAYLOAD_BLOCK_UNMAPPED:
1206            case PAYLOAD_BLOCK_UNMAPPED_v095:
1207            case PAYLOAD_BLOCK_ZERO:
1208                /* return zero */
1209                qemu_iovec_memset(&hd_qiov, 0, 0, sinfo.bytes_avail);
1210                break;
1211            case PAYLOAD_BLOCK_FULLY_PRESENT:
1212                qemu_co_mutex_unlock(&s->lock);
1213                ret = bdrv_co_preadv(bs->file, sinfo.file_offset,
1214                                     sinfo.sectors_avail * BDRV_SECTOR_SIZE,
1215                                     &hd_qiov, 0);
1216                qemu_co_mutex_lock(&s->lock);
1217                if (ret < 0) {
1218                    goto exit;
1219                }
1220                break;
1221            case PAYLOAD_BLOCK_PARTIALLY_PRESENT:
1222                /* we don't yet support difference files, fall through
1223                 * to error */
1224            default:
1225                ret = -EIO;
1226                goto exit;
1227                break;
1228            }
1229            nb_sectors -= sinfo.sectors_avail;
1230            sector_num += sinfo.sectors_avail;
1231            bytes_done += sinfo.bytes_avail;
1232        }
1233    }
1234    ret = 0;
1235exit:
1236    qemu_co_mutex_unlock(&s->lock);
1237    qemu_iovec_destroy(&hd_qiov);
1238    return ret;
1239}
1240
1241/*
1242 * Allocate a new payload block at the end of the file.
1243 *
1244 * Allocation will happen at 1MB alignment inside the file
1245 *
1246 * Returns the file offset start of the new payload block
1247 */
1248static int vhdx_allocate_block(BlockDriverState *bs, BDRVVHDXState *s,
1249                                    uint64_t *new_offset)
1250{
1251    int64_t current_len;
1252
1253    current_len = bdrv_getlength(bs->file->bs);
1254    if (current_len < 0) {
1255        return current_len;
1256    }
1257
1258    *new_offset = current_len;
1259
1260    /* per the spec, the address for a block is in units of 1MB */
1261    *new_offset = ROUND_UP(*new_offset, 1 * MiB);
1262    if (*new_offset > INT64_MAX) {
1263        return -EINVAL;
1264    }
1265
1266    return bdrv_truncate(bs->file, *new_offset + s->block_size, false,
1267                         PREALLOC_MODE_OFF, NULL);
1268}
1269
1270/*
1271 * Update the BAT table entry with the new file offset, and the new entry
1272 * state */
1273static void vhdx_update_bat_table_entry(BlockDriverState *bs, BDRVVHDXState *s,
1274                                       VHDXSectorInfo *sinfo,
1275                                       uint64_t *bat_entry_le,
1276                                       uint64_t *bat_offset, int state)
1277{
1278    /* The BAT entry is a uint64, with 44 bits for the file offset in units of
1279     * 1MB, and 3 bits for the block state. */
1280    if ((state == PAYLOAD_BLOCK_ZERO)        ||
1281        (state == PAYLOAD_BLOCK_UNDEFINED)   ||
1282        (state == PAYLOAD_BLOCK_NOT_PRESENT) ||
1283        (state == PAYLOAD_BLOCK_UNMAPPED)) {
1284        s->bat[sinfo->bat_idx]  = 0;  /* For PAYLOAD_BLOCK_ZERO, the
1285                                         FileOffsetMB field is denoted as
1286                                         'reserved' in the v1.0 spec.  If it is
1287                                         non-zero, MS Hyper-V will fail to read
1288                                         the disk image */
1289    } else {
1290        s->bat[sinfo->bat_idx]  = sinfo->file_offset;
1291    }
1292
1293    s->bat[sinfo->bat_idx] |= state & VHDX_BAT_STATE_BIT_MASK;
1294
1295    *bat_entry_le = cpu_to_le64(s->bat[sinfo->bat_idx]);
1296    *bat_offset = s->bat_offset + sinfo->bat_idx * sizeof(VHDXBatEntry);
1297
1298}
1299
1300/* Per the spec, on the first write of guest-visible data to the file the
1301 * data write guid must be updated in the header */
1302int vhdx_user_visible_write(BlockDriverState *bs, BDRVVHDXState *s)
1303{
1304    int ret = 0;
1305    if (s->first_visible_write) {
1306        s->first_visible_write = false;
1307        ret = vhdx_update_headers(bs, s, true, NULL);
1308    }
1309    return ret;
1310}
1311
1312static coroutine_fn int vhdx_co_writev(BlockDriverState *bs, int64_t sector_num,
1313                                       int nb_sectors, QEMUIOVector *qiov,
1314                                       int flags)
1315{
1316    int ret = -ENOTSUP;
1317    BDRVVHDXState *s = bs->opaque;
1318    VHDXSectorInfo sinfo;
1319    uint64_t bytes_done = 0;
1320    uint64_t bat_entry = 0;
1321    uint64_t bat_entry_offset = 0;
1322    QEMUIOVector hd_qiov;
1323    struct iovec iov1 = { 0 };
1324    struct iovec iov2 = { 0 };
1325    int sectors_to_write;
1326    int bat_state;
1327    uint64_t bat_prior_offset = 0;
1328    bool bat_update = false;
1329
1330    assert(!flags);
1331    qemu_iovec_init(&hd_qiov, qiov->niov);
1332
1333    qemu_co_mutex_lock(&s->lock);
1334
1335    ret = vhdx_user_visible_write(bs, s);
1336    if (ret < 0) {
1337        goto exit;
1338    }
1339
1340    while (nb_sectors > 0) {
1341        bool use_zero_buffers = false;
1342        bat_update = false;
1343        if (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) {
1344            /* not supported yet */
1345            ret = -ENOTSUP;
1346            goto exit;
1347        } else {
1348            vhdx_block_translate(s, sector_num, nb_sectors, &sinfo);
1349            sectors_to_write = sinfo.sectors_avail;
1350
1351            qemu_iovec_reset(&hd_qiov);
1352            /* check the payload block state */
1353            bat_state = s->bat[sinfo.bat_idx] & VHDX_BAT_STATE_BIT_MASK;
1354            switch (bat_state) {
1355            case PAYLOAD_BLOCK_ZERO:
1356                /* in this case, we need to preserve zero writes for
1357                 * data that is not part of this write, so we must pad
1358                 * the rest of the buffer to zeroes */
1359
1360                /* if we are on a posix system with ftruncate() that extends
1361                 * a file, then it is zero-filled for us.  On Win32, the raw
1362                 * layer uses SetFilePointer and SetFileEnd, which does not
1363                 * zero fill AFAIK */
1364
1365                /* Queue another write of zero buffers if the underlying file
1366                 * does not zero-fill on file extension */
1367
1368                if (bdrv_has_zero_init_truncate(bs->file->bs) == 0) {
1369                    use_zero_buffers = true;
1370
1371                    /* zero fill the front, if any */
1372                    if (sinfo.block_offset) {
1373                        iov1.iov_len = sinfo.block_offset;
1374                        iov1.iov_base = qemu_blockalign(bs, iov1.iov_len);
1375                        memset(iov1.iov_base, 0, iov1.iov_len);
1376                        qemu_iovec_concat_iov(&hd_qiov, &iov1, 1, 0,
1377                                              iov1.iov_len);
1378                        sectors_to_write += iov1.iov_len >> BDRV_SECTOR_BITS;
1379                    }
1380
1381                    /* our actual data */
1382                    qemu_iovec_concat(&hd_qiov, qiov,  bytes_done,
1383                                      sinfo.bytes_avail);
1384
1385                    /* zero fill the back, if any */
1386                    if ((sinfo.bytes_avail - sinfo.block_offset) <
1387                         s->block_size) {
1388                        iov2.iov_len = s->block_size -
1389                                      (sinfo.bytes_avail + sinfo.block_offset);
1390                        iov2.iov_base = qemu_blockalign(bs, iov2.iov_len);
1391                        memset(iov2.iov_base, 0, iov2.iov_len);
1392                        qemu_iovec_concat_iov(&hd_qiov, &iov2, 1, 0,
1393                                              iov2.iov_len);
1394                        sectors_to_write += iov2.iov_len >> BDRV_SECTOR_BITS;
1395                    }
1396                }
1397                /* fall through */
1398            case PAYLOAD_BLOCK_NOT_PRESENT: /* fall through */
1399            case PAYLOAD_BLOCK_UNMAPPED:
1400            case PAYLOAD_BLOCK_UNMAPPED_v095:
1401            case PAYLOAD_BLOCK_UNDEFINED:
1402                bat_prior_offset = sinfo.file_offset;
1403                ret = vhdx_allocate_block(bs, s, &sinfo.file_offset);
1404                if (ret < 0) {
1405                    goto exit;
1406                }
1407                /* once we support differencing files, this may also be
1408                 * partially present */
1409                /* update block state to the newly specified state */
1410                vhdx_update_bat_table_entry(bs, s, &sinfo, &bat_entry,
1411                                            &bat_entry_offset,
1412                                            PAYLOAD_BLOCK_FULLY_PRESENT);
1413                bat_update = true;
1414                /* since we just allocated a block, file_offset is the
1415                 * beginning of the payload block. It needs to be the
1416                 * write address, which includes the offset into the block */
1417                if (!use_zero_buffers) {
1418                    sinfo.file_offset += sinfo.block_offset;
1419                }
1420                /* fall through */
1421            case PAYLOAD_BLOCK_FULLY_PRESENT:
1422                /* if the file offset address is in the header zone,
1423                 * there is a problem */
1424                if (sinfo.file_offset < (1 * MiB)) {
1425                    ret = -EFAULT;
1426                    goto error_bat_restore;
1427                }
1428
1429                if (!use_zero_buffers) {
1430                    qemu_iovec_concat(&hd_qiov, qiov,  bytes_done,
1431                                      sinfo.bytes_avail);
1432                }
1433                /* block exists, so we can just overwrite it */
1434                qemu_co_mutex_unlock(&s->lock);
1435                ret = bdrv_co_pwritev(bs->file, sinfo.file_offset,
1436                                      sectors_to_write * BDRV_SECTOR_SIZE,
1437                                      &hd_qiov, 0);
1438                qemu_co_mutex_lock(&s->lock);
1439                if (ret < 0) {
1440                    goto error_bat_restore;
1441                }
1442                break;
1443            case PAYLOAD_BLOCK_PARTIALLY_PRESENT:
1444                /* we don't yet support difference files, fall through
1445                 * to error */
1446            default:
1447                ret = -EIO;
1448                goto exit;
1449                break;
1450            }
1451
1452            if (bat_update) {
1453                /* this will update the BAT entry into the log journal, and
1454                 * then flush the log journal out to disk */
1455                ret =  vhdx_log_write_and_flush(bs, s, &bat_entry,
1456                                                sizeof(VHDXBatEntry),
1457                                                bat_entry_offset);
1458                if (ret < 0) {
1459                    goto exit;
1460                }
1461            }
1462
1463            nb_sectors -= sinfo.sectors_avail;
1464            sector_num += sinfo.sectors_avail;
1465            bytes_done += sinfo.bytes_avail;
1466
1467        }
1468    }
1469
1470    goto exit;
1471
1472error_bat_restore:
1473    if (bat_update) {
1474        /* keep metadata in sync, and restore the bat entry state
1475         * if error. */
1476        sinfo.file_offset = bat_prior_offset;
1477        vhdx_update_bat_table_entry(bs, s, &sinfo, &bat_entry,
1478                                    &bat_entry_offset, bat_state);
1479    }
1480exit:
1481    qemu_vfree(iov1.iov_base);
1482    qemu_vfree(iov2.iov_base);
1483    qemu_co_mutex_unlock(&s->lock);
1484    qemu_iovec_destroy(&hd_qiov);
1485    return ret;
1486}
1487
1488
1489
1490/*
1491 * Create VHDX Headers
1492 *
1493 * There are 2 headers, and the highest sequence number will represent
1494 * the active header
1495 */
1496static int vhdx_create_new_headers(BlockBackend *blk, uint64_t image_size,
1497                                   uint32_t log_size)
1498{
1499    BlockDriverState *bs = blk_bs(blk);
1500    BdrvChild *child;
1501    int ret = 0;
1502    VHDXHeader *hdr = NULL;
1503
1504    hdr = g_new0(VHDXHeader, 1);
1505
1506    hdr->signature       = VHDX_HEADER_SIGNATURE;
1507    hdr->sequence_number = g_random_int();
1508    hdr->log_version     = 0;
1509    hdr->version         = 1;
1510    hdr->log_length      = log_size;
1511    hdr->log_offset      = VHDX_HEADER_SECTION_END;
1512    vhdx_guid_generate(&hdr->file_write_guid);
1513    vhdx_guid_generate(&hdr->data_write_guid);
1514
1515    /* XXX Ugly way to get blk->root, but that's a feature, not a bug. This
1516     * hack makes it obvious that vhdx_write_header() bypasses the BlockBackend
1517     * here, which it really shouldn't be doing. */
1518    child = QLIST_FIRST(&bs->parents);
1519    assert(!QLIST_NEXT(child, next_parent));
1520
1521    ret = vhdx_write_header(child, hdr, VHDX_HEADER1_OFFSET, false);
1522    if (ret < 0) {
1523        goto exit;
1524    }
1525    hdr->sequence_number++;
1526    ret = vhdx_write_header(child, hdr, VHDX_HEADER2_OFFSET, false);
1527    if (ret < 0) {
1528        goto exit;
1529    }
1530
1531exit:
1532    g_free(hdr);
1533    return ret;
1534}
1535
1536#define VHDX_METADATA_ENTRY_BUFFER_SIZE \
1537                                    (sizeof(VHDXFileParameters)               +\
1538                                     sizeof(VHDXVirtualDiskSize)              +\
1539                                     sizeof(VHDXPage83Data)                   +\
1540                                     sizeof(VHDXVirtualDiskLogicalSectorSize) +\
1541                                     sizeof(VHDXVirtualDiskPhysicalSectorSize))
1542
1543/*
1544 * Create the Metadata entries.
1545 *
1546 * For more details on the entries, see section 3.5 (pg 29) in the
1547 * VHDX 1.00 specification.
1548 *
1549 * We support 5 metadata entries (all required by spec):
1550 *          File Parameters,
1551 *          Virtual Disk Size,
1552 *          Page 83 Data,
1553 *          Logical Sector Size,
1554 *          Physical Sector Size
1555 *
1556 * The first 64KB of the Metadata section is reserved for the metadata
1557 * header and entries; beyond that, the metadata items themselves reside.
1558 */
1559static int vhdx_create_new_metadata(BlockBackend *blk,
1560                                    uint64_t image_size,
1561                                    uint32_t block_size,
1562                                    uint32_t sector_size,
1563                                    uint64_t metadata_offset,
1564                                    VHDXImageType type)
1565{
1566    int ret = 0;
1567    uint32_t offset = 0;
1568    void *buffer = NULL;
1569    void *entry_buffer;
1570    VHDXMetadataTableHeader *md_table;
1571    VHDXMetadataTableEntry  *md_table_entry;
1572
1573    /* Metadata entries */
1574    VHDXFileParameters     *mt_file_params;
1575    VHDXVirtualDiskSize    *mt_virtual_size;
1576    VHDXPage83Data         *mt_page83;
1577    VHDXVirtualDiskLogicalSectorSize  *mt_log_sector_size;
1578    VHDXVirtualDiskPhysicalSectorSize *mt_phys_sector_size;
1579
1580    entry_buffer = g_malloc0(VHDX_METADATA_ENTRY_BUFFER_SIZE);
1581
1582    mt_file_params = entry_buffer;
1583    offset += sizeof(VHDXFileParameters);
1584    mt_virtual_size = entry_buffer + offset;
1585    offset += sizeof(VHDXVirtualDiskSize);
1586    mt_page83 = entry_buffer + offset;
1587    offset += sizeof(VHDXPage83Data);
1588    mt_log_sector_size = entry_buffer + offset;
1589    offset += sizeof(VHDXVirtualDiskLogicalSectorSize);
1590    mt_phys_sector_size = entry_buffer + offset;
1591
1592    mt_file_params->block_size = cpu_to_le32(block_size);
1593    if (type == VHDX_TYPE_FIXED) {
1594        mt_file_params->data_bits |= VHDX_PARAMS_LEAVE_BLOCKS_ALLOCED;
1595        mt_file_params->data_bits = cpu_to_le32(mt_file_params->data_bits);
1596    }
1597
1598    vhdx_guid_generate(&mt_page83->page_83_data);
1599    cpu_to_leguids(&mt_page83->page_83_data);
1600    mt_virtual_size->virtual_disk_size        = cpu_to_le64(image_size);
1601    mt_log_sector_size->logical_sector_size   = cpu_to_le32(sector_size);
1602    mt_phys_sector_size->physical_sector_size = cpu_to_le32(sector_size);
1603
1604    buffer = g_malloc0(VHDX_HEADER_BLOCK_SIZE);
1605    md_table = buffer;
1606
1607    md_table->signature   = VHDX_METADATA_SIGNATURE;
1608    md_table->entry_count = 5;
1609    vhdx_metadata_header_le_export(md_table);
1610
1611
1612    /* This will reference beyond the reserved table portion */
1613    offset = 64 * KiB;
1614
1615    md_table_entry = buffer + sizeof(VHDXMetadataTableHeader);
1616
1617    md_table_entry[0].item_id = file_param_guid;
1618    md_table_entry[0].offset  = offset;
1619    md_table_entry[0].length  = sizeof(VHDXFileParameters);
1620    md_table_entry[0].data_bits |= VHDX_META_FLAGS_IS_REQUIRED;
1621    offset += md_table_entry[0].length;
1622    vhdx_metadata_entry_le_export(&md_table_entry[0]);
1623
1624    md_table_entry[1].item_id = virtual_size_guid;
1625    md_table_entry[1].offset  = offset;
1626    md_table_entry[1].length  = sizeof(VHDXVirtualDiskSize);
1627    md_table_entry[1].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
1628                                   VHDX_META_FLAGS_IS_VIRTUAL_DISK;
1629    offset += md_table_entry[1].length;
1630    vhdx_metadata_entry_le_export(&md_table_entry[1]);
1631
1632    md_table_entry[2].item_id = page83_guid;
1633    md_table_entry[2].offset  = offset;
1634    md_table_entry[2].length  = sizeof(VHDXPage83Data);
1635    md_table_entry[2].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
1636                                   VHDX_META_FLAGS_IS_VIRTUAL_DISK;
1637    offset += md_table_entry[2].length;
1638    vhdx_metadata_entry_le_export(&md_table_entry[2]);
1639
1640    md_table_entry[3].item_id = logical_sector_guid;
1641    md_table_entry[3].offset  = offset;
1642    md_table_entry[3].length  = sizeof(VHDXVirtualDiskLogicalSectorSize);
1643    md_table_entry[3].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
1644                                   VHDX_META_FLAGS_IS_VIRTUAL_DISK;
1645    offset += md_table_entry[3].length;
1646    vhdx_metadata_entry_le_export(&md_table_entry[3]);
1647
1648    md_table_entry[4].item_id = phys_sector_guid;
1649    md_table_entry[4].offset  = offset;
1650    md_table_entry[4].length  = sizeof(VHDXVirtualDiskPhysicalSectorSize);
1651    md_table_entry[4].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
1652                                   VHDX_META_FLAGS_IS_VIRTUAL_DISK;
1653    vhdx_metadata_entry_le_export(&md_table_entry[4]);
1654
1655    ret = blk_pwrite(blk, metadata_offset, buffer, VHDX_HEADER_BLOCK_SIZE, 0);
1656    if (ret < 0) {
1657        goto exit;
1658    }
1659
1660    ret = blk_pwrite(blk, metadata_offset + (64 * KiB), entry_buffer,
1661                     VHDX_METADATA_ENTRY_BUFFER_SIZE, 0);
1662    if (ret < 0) {
1663        goto exit;
1664    }
1665
1666
1667exit:
1668    g_free(buffer);
1669    g_free(entry_buffer);
1670    return ret;
1671}
1672
1673/* This create the actual BAT itself.  We currently only support
1674 * 'Dynamic' and 'Fixed' image types.
1675 *
1676 *  Dynamic images: default state of the BAT is all zeroes.
1677 *
1678 *  Fixed images: default state of the BAT is fully populated, with
1679 *                file offsets and state PAYLOAD_BLOCK_FULLY_PRESENT.
1680 */
1681static int vhdx_create_bat(BlockBackend *blk, BDRVVHDXState *s,
1682                           uint64_t image_size, VHDXImageType type,
1683                           bool use_zero_blocks, uint64_t file_offset,
1684                           uint32_t length, Error **errp)
1685{
1686    int ret = 0;
1687    uint64_t data_file_offset;
1688    uint64_t total_sectors = 0;
1689    uint64_t sector_num = 0;
1690    uint64_t unused;
1691    int block_state;
1692    VHDXSectorInfo sinfo;
1693
1694    assert(s->bat == NULL);
1695
1696    /* this gives a data start after BAT/bitmap entries, and well
1697     * past any metadata entries (with a 4 MB buffer for future
1698     * expansion */
1699    data_file_offset = file_offset + length + 5 * MiB;
1700    total_sectors = image_size >> s->logical_sector_size_bits;
1701
1702    if (type == VHDX_TYPE_DYNAMIC) {
1703        /* All zeroes, so we can just extend the file - the end of the BAT
1704         * is the furthest thing we have written yet */
1705        ret = blk_truncate(blk, data_file_offset, false, PREALLOC_MODE_OFF,
1706                           errp);
1707        if (ret < 0) {
1708            goto exit;
1709        }
1710    } else if (type == VHDX_TYPE_FIXED) {
1711        ret = blk_truncate(blk, data_file_offset + image_size, false,
1712                           PREALLOC_MODE_OFF, errp);
1713        if (ret < 0) {
1714            goto exit;
1715        }
1716    } else {
1717        error_setg(errp, "Unsupported image type");
1718        ret = -ENOTSUP;
1719        goto exit;
1720    }
1721
1722    if (type == VHDX_TYPE_FIXED ||
1723                use_zero_blocks ||
1724                bdrv_has_zero_init(blk_bs(blk)) == 0) {
1725        /* for a fixed file, the default BAT entry is not zero */
1726        s->bat = g_try_malloc0(length);
1727        if (length && s->bat == NULL) {
1728            error_setg(errp, "Failed to allocate memory for the BAT");
1729            ret = -ENOMEM;
1730            goto exit;
1731        }
1732        block_state = type == VHDX_TYPE_FIXED ? PAYLOAD_BLOCK_FULLY_PRESENT :
1733                                                PAYLOAD_BLOCK_NOT_PRESENT;
1734        block_state = use_zero_blocks ? PAYLOAD_BLOCK_ZERO : block_state;
1735        /* fill the BAT by emulating sector writes of sectors_per_block size */
1736        while (sector_num < total_sectors) {
1737            vhdx_block_translate(s, sector_num, s->sectors_per_block, &sinfo);
1738            sinfo.file_offset = data_file_offset +
1739                                (sector_num << s->logical_sector_size_bits);
1740            sinfo.file_offset = ROUND_UP(sinfo.file_offset, MiB);
1741            vhdx_update_bat_table_entry(blk_bs(blk), s, &sinfo, &unused, &unused,
1742                                        block_state);
1743            s->bat[sinfo.bat_idx] = cpu_to_le64(s->bat[sinfo.bat_idx]);
1744            sector_num += s->sectors_per_block;
1745        }
1746        ret = blk_pwrite(blk, file_offset, s->bat, length, 0);
1747        if (ret < 0) {
1748            error_setg_errno(errp, -ret, "Failed to write the BAT");
1749            goto exit;
1750        }
1751    }
1752
1753
1754
1755exit:
1756    g_free(s->bat);
1757    return ret;
1758}
1759
1760/* Creates the region table header, and region table entries.
1761 * There are 2 supported region table entries: BAT, and Metadata/
1762 *
1763 * As the calculations for the BAT region table are also needed
1764 * to create the BAT itself, we will also cause the BAT to be
1765 * created.
1766 */
1767static int vhdx_create_new_region_table(BlockBackend *blk,
1768                                        uint64_t image_size,
1769                                        uint32_t block_size,
1770                                        uint32_t sector_size,
1771                                        uint32_t log_size,
1772                                        bool use_zero_blocks,
1773                                        VHDXImageType type,
1774                                        uint64_t *metadata_offset,
1775                                        Error **errp)
1776{
1777    int ret = 0;
1778    uint32_t offset = 0;
1779    void *buffer = NULL;
1780    uint64_t bat_file_offset;
1781    uint32_t bat_length;
1782    BDRVVHDXState *s = NULL;
1783    VHDXRegionTableHeader *region_table;
1784    VHDXRegionTableEntry *rt_bat;
1785    VHDXRegionTableEntry *rt_metadata;
1786
1787    assert(metadata_offset != NULL);
1788
1789    /* Populate enough of the BDRVVHDXState to be able to use the
1790     * pre-existing BAT calculation, translation, and update functions */
1791    s = g_new0(BDRVVHDXState, 1);
1792
1793    s->chunk_ratio = (VHDX_MAX_SECTORS_PER_BLOCK) *
1794                     (uint64_t) sector_size / (uint64_t) block_size;
1795
1796    s->sectors_per_block = block_size / sector_size;
1797    s->virtual_disk_size = image_size;
1798    s->block_size = block_size;
1799    s->logical_sector_size = sector_size;
1800
1801    vhdx_set_shift_bits(s);
1802
1803    vhdx_calc_bat_entries(s);
1804
1805    /* At this point the VHDX state is populated enough for creation */
1806
1807    /* a single buffer is used so we can calculate the checksum over the
1808     * entire 64KB block */
1809    buffer = g_malloc0(VHDX_HEADER_BLOCK_SIZE);
1810    region_table = buffer;
1811    offset += sizeof(VHDXRegionTableHeader);
1812    rt_bat = buffer + offset;
1813    offset += sizeof(VHDXRegionTableEntry);
1814    rt_metadata  = buffer + offset;
1815
1816    region_table->signature = VHDX_REGION_SIGNATURE;
1817    region_table->entry_count = 2;   /* BAT and Metadata */
1818
1819    rt_bat->guid        = bat_guid;
1820    rt_bat->length      = ROUND_UP(s->bat_entries * sizeof(VHDXBatEntry), MiB);
1821    rt_bat->file_offset = ROUND_UP(VHDX_HEADER_SECTION_END + log_size, MiB);
1822    s->bat_offset = rt_bat->file_offset;
1823
1824    rt_metadata->guid        = metadata_guid;
1825    rt_metadata->file_offset = ROUND_UP(rt_bat->file_offset + rt_bat->length,
1826                                        MiB);
1827    rt_metadata->length      = 1 * MiB; /* min size, and more than enough */
1828    *metadata_offset = rt_metadata->file_offset;
1829
1830    bat_file_offset = rt_bat->file_offset;
1831    bat_length = rt_bat->length;
1832
1833    vhdx_region_header_le_export(region_table);
1834    vhdx_region_entry_le_export(rt_bat);
1835    vhdx_region_entry_le_export(rt_metadata);
1836
1837    vhdx_update_checksum(buffer, VHDX_HEADER_BLOCK_SIZE,
1838                         offsetof(VHDXRegionTableHeader, checksum));
1839
1840
1841    /* The region table gives us the data we need to create the BAT,
1842     * so do that now */
1843    ret = vhdx_create_bat(blk, s, image_size, type, use_zero_blocks,
1844                          bat_file_offset, bat_length, errp);
1845    if (ret < 0) {
1846        goto exit;
1847    }
1848
1849    /* Now write out the region headers to disk */
1850    ret = blk_pwrite(blk, VHDX_REGION_TABLE_OFFSET, buffer,
1851                     VHDX_HEADER_BLOCK_SIZE, 0);
1852    if (ret < 0) {
1853        error_setg_errno(errp, -ret, "Failed to write first region table");
1854        goto exit;
1855    }
1856
1857    ret = blk_pwrite(blk, VHDX_REGION_TABLE2_OFFSET, buffer,
1858                     VHDX_HEADER_BLOCK_SIZE, 0);
1859    if (ret < 0) {
1860        error_setg_errno(errp, -ret, "Failed to write second region table");
1861        goto exit;
1862    }
1863
1864exit:
1865    g_free(s);
1866    g_free(buffer);
1867    return ret;
1868}
1869
1870/* We need to create the following elements:
1871 *
1872 *    .-----------------------------------------------------------------.
1873 *    |   (A)    |   (B)    |    (C)    |     (D)       |     (E)       |
1874 *    |  File ID |  Header1 |  Header 2 |  Region Tbl 1 |  Region Tbl 2 |
1875 *    |          |          |           |               |               |
1876 *    .-----------------------------------------------------------------.
1877 *    0         64KB      128KB       192KB           256KB           320KB
1878 *
1879 *
1880 *    .---- ~ ----------- ~ ------------ ~ ---------------- ~ -----------.
1881 *    |     (F)     |     (G)       |    (H)    |                        |
1882 *    | Journal Log |  BAT / Bitmap |  Metadata |  .... data ......      |
1883 *    |             |               |           |                        |
1884 *    .---- ~ ----------- ~ ------------ ~ ---------------- ~ -----------.
1885 *   1MB
1886 */
1887static int coroutine_fn vhdx_co_create(BlockdevCreateOptions *opts,
1888                                       Error **errp)
1889{
1890    BlockdevCreateOptionsVhdx *vhdx_opts;
1891    BlockBackend *blk = NULL;
1892    BlockDriverState *bs = NULL;
1893
1894    int ret = 0;
1895    uint64_t image_size;
1896    uint32_t log_size;
1897    uint32_t block_size;
1898    uint64_t signature;
1899    uint64_t metadata_offset;
1900    bool use_zero_blocks = false;
1901
1902    gunichar2 *creator = NULL;
1903    glong creator_items;
1904    VHDXImageType image_type;
1905
1906    assert(opts->driver == BLOCKDEV_DRIVER_VHDX);
1907    vhdx_opts = &opts->u.vhdx;
1908
1909    /* Validate options and set default values */
1910    image_size = vhdx_opts->size;
1911    if (image_size > VHDX_MAX_IMAGE_SIZE) {
1912        error_setg(errp, "Image size too large; max of 64TB");
1913        return -EINVAL;
1914    }
1915
1916    if (!vhdx_opts->has_log_size) {
1917        log_size = DEFAULT_LOG_SIZE;
1918    } else {
1919        if (vhdx_opts->log_size > UINT32_MAX) {
1920            error_setg(errp, "Log size must be smaller than 4 GB");
1921            return -EINVAL;
1922        }
1923        log_size = vhdx_opts->log_size;
1924    }
1925    if (log_size < MiB || (log_size % MiB) != 0) {
1926        error_setg(errp, "Log size must be a multiple of 1 MB");
1927        return -EINVAL;
1928    }
1929
1930    if (!vhdx_opts->has_block_state_zero) {
1931        use_zero_blocks = true;
1932    } else {
1933        use_zero_blocks = vhdx_opts->block_state_zero;
1934    }
1935
1936    if (!vhdx_opts->has_subformat) {
1937        vhdx_opts->subformat = BLOCKDEV_VHDX_SUBFORMAT_DYNAMIC;
1938    }
1939
1940    switch (vhdx_opts->subformat) {
1941    case BLOCKDEV_VHDX_SUBFORMAT_DYNAMIC:
1942        image_type = VHDX_TYPE_DYNAMIC;
1943        break;
1944    case BLOCKDEV_VHDX_SUBFORMAT_FIXED:
1945        image_type = VHDX_TYPE_FIXED;
1946        break;
1947    default:
1948        g_assert_not_reached();
1949    }
1950
1951    /* These are pretty arbitrary, and mainly designed to keep the BAT
1952     * size reasonable to load into RAM */
1953    if (vhdx_opts->has_block_size) {
1954        block_size = vhdx_opts->block_size;
1955    } else {
1956        if (image_size > 32 * TiB) {
1957            block_size = 64 * MiB;
1958        } else if (image_size > (uint64_t) 100 * GiB) {
1959            block_size = 32 * MiB;
1960        } else if (image_size > 1 * GiB) {
1961            block_size = 16 * MiB;
1962        } else {
1963            block_size = 8 * MiB;
1964        }
1965    }
1966
1967    if (block_size < MiB || (block_size % MiB) != 0) {
1968        error_setg(errp, "Block size must be a multiple of 1 MB");
1969        return -EINVAL;
1970    }
1971    if (!is_power_of_2(block_size)) {
1972        error_setg(errp, "Block size must be a power of two");
1973        return -EINVAL;
1974    }
1975    if (block_size > VHDX_BLOCK_SIZE_MAX) {
1976        error_setg(errp, "Block size must not exceed %" PRId64,
1977                   VHDX_BLOCK_SIZE_MAX);
1978        return -EINVAL;
1979    }
1980
1981    /* Create BlockBackend to write to the image */
1982    bs = bdrv_open_blockdev_ref(vhdx_opts->file, errp);
1983    if (bs == NULL) {
1984        return -EIO;
1985    }
1986
1987    blk = blk_new(bdrv_get_aio_context(bs),
1988                  BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL);
1989    ret = blk_insert_bs(blk, bs, errp);
1990    if (ret < 0) {
1991        goto delete_and_exit;
1992    }
1993    blk_set_allow_write_beyond_eof(blk, true);
1994
1995    /* Create (A) */
1996
1997    /* The creator field is optional, but may be useful for
1998     * debugging / diagnostics */
1999    creator = g_utf8_to_utf16("QEMU v" QEMU_VERSION, -1, NULL,
2000                              &creator_items, NULL);
2001    signature = cpu_to_le64(VHDX_FILE_SIGNATURE);
2002    ret = blk_pwrite(blk, VHDX_FILE_ID_OFFSET, &signature, sizeof(signature),
2003                     0);
2004    if (ret < 0) {
2005        error_setg_errno(errp, -ret, "Failed to write file signature");
2006        goto delete_and_exit;
2007    }
2008    if (creator) {
2009        ret = blk_pwrite(blk, VHDX_FILE_ID_OFFSET + sizeof(signature),
2010                         creator, creator_items * sizeof(gunichar2), 0);
2011        if (ret < 0) {
2012            error_setg_errno(errp, -ret, "Failed to write creator field");
2013            goto delete_and_exit;
2014        }
2015    }
2016
2017
2018    /* Creates (B),(C) */
2019    ret = vhdx_create_new_headers(blk, image_size, log_size);
2020    if (ret < 0) {
2021        error_setg_errno(errp, -ret, "Failed to write image headers");
2022        goto delete_and_exit;
2023    }
2024
2025    /* Creates (D),(E),(G) explicitly. (F) created as by-product */
2026    ret = vhdx_create_new_region_table(blk, image_size, block_size, 512,
2027                                       log_size, use_zero_blocks, image_type,
2028                                       &metadata_offset, errp);
2029    if (ret < 0) {
2030        goto delete_and_exit;
2031    }
2032
2033    /* Creates (H) */
2034    ret = vhdx_create_new_metadata(blk, image_size, block_size, 512,
2035                                   metadata_offset, image_type);
2036    if (ret < 0) {
2037        error_setg_errno(errp, -ret, "Failed to initialize metadata");
2038        goto delete_and_exit;
2039    }
2040
2041    ret = 0;
2042delete_and_exit:
2043    blk_unref(blk);
2044    bdrv_unref(bs);
2045    g_free(creator);
2046    return ret;
2047}
2048
2049static int coroutine_fn vhdx_co_create_opts(BlockDriver *drv,
2050                                            const char *filename,
2051                                            QemuOpts *opts,
2052                                            Error **errp)
2053{
2054    BlockdevCreateOptions *create_options = NULL;
2055    QDict *qdict;
2056    Visitor *v;
2057    BlockDriverState *bs = NULL;
2058    Error *local_err = NULL;
2059    int ret;
2060
2061    static const QDictRenames opt_renames[] = {
2062        { VHDX_BLOCK_OPT_LOG_SIZE,      "log-size" },
2063        { VHDX_BLOCK_OPT_BLOCK_SIZE,    "block-size" },
2064        { VHDX_BLOCK_OPT_ZERO,          "block-state-zero" },
2065        { NULL, NULL },
2066    };
2067
2068    /* Parse options and convert legacy syntax */
2069    qdict = qemu_opts_to_qdict_filtered(opts, NULL, &vhdx_create_opts, true);
2070
2071    if (!qdict_rename_keys(qdict, opt_renames, errp)) {
2072        ret = -EINVAL;
2073        goto fail;
2074    }
2075
2076    /* Create and open the file (protocol layer) */
2077    ret = bdrv_create_file(filename, opts, &local_err);
2078    if (ret < 0) {
2079        error_propagate(errp, local_err);
2080        goto fail;
2081    }
2082
2083    bs = bdrv_open(filename, NULL, NULL,
2084                   BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp);
2085    if (bs == NULL) {
2086        ret = -EIO;
2087        goto fail;
2088    }
2089
2090    /* Now get the QAPI type BlockdevCreateOptions */
2091    qdict_put_str(qdict, "driver", "vhdx");
2092    qdict_put_str(qdict, "file", bs->node_name);
2093
2094    v = qobject_input_visitor_new_flat_confused(qdict, errp);
2095    if (!v) {
2096        ret = -EINVAL;
2097        goto fail;
2098    }
2099
2100    visit_type_BlockdevCreateOptions(v, NULL, &create_options, &local_err);
2101    visit_free(v);
2102
2103    if (local_err) {
2104        error_propagate(errp, local_err);
2105        ret = -EINVAL;
2106        goto fail;
2107    }
2108
2109    /* Silently round up sizes:
2110     * The image size is rounded to 512 bytes. Make the block and log size
2111     * close to what was specified, but must be at least 1MB, and a multiple of
2112     * 1 MB. Also respect VHDX_BLOCK_SIZE_MAX for block sizes. block_size = 0
2113     * means auto, which is represented by a missing key in QAPI. */
2114    assert(create_options->driver == BLOCKDEV_DRIVER_VHDX);
2115    create_options->u.vhdx.size =
2116        ROUND_UP(create_options->u.vhdx.size, BDRV_SECTOR_SIZE);
2117
2118    if (create_options->u.vhdx.has_log_size) {
2119        create_options->u.vhdx.log_size =
2120            ROUND_UP(create_options->u.vhdx.log_size, MiB);
2121    }
2122    if (create_options->u.vhdx.has_block_size) {
2123        create_options->u.vhdx.block_size =
2124            ROUND_UP(create_options->u.vhdx.block_size, MiB);
2125
2126        if (create_options->u.vhdx.block_size == 0) {
2127            create_options->u.vhdx.has_block_size = false;
2128        }
2129        if (create_options->u.vhdx.block_size > VHDX_BLOCK_SIZE_MAX) {
2130            create_options->u.vhdx.block_size = VHDX_BLOCK_SIZE_MAX;
2131        }
2132    }
2133
2134    /* Create the vhdx image (format layer) */
2135    ret = vhdx_co_create(create_options, errp);
2136
2137fail:
2138    qobject_unref(qdict);
2139    bdrv_unref(bs);
2140    qapi_free_BlockdevCreateOptions(create_options);
2141    return ret;
2142}
2143
2144/* If opened r/w, the VHDX driver will automatically replay the log,
2145 * if one is present, inside the vhdx_open() call.
2146 *
2147 * If qemu-img check -r all is called, the image is automatically opened
2148 * r/w and any log has already been replayed, so there is nothing (currently)
2149 * for us to do here
2150 */
2151static int coroutine_fn vhdx_co_check(BlockDriverState *bs,
2152                                      BdrvCheckResult *result,
2153                                      BdrvCheckMode fix)
2154{
2155    BDRVVHDXState *s = bs->opaque;
2156
2157    if (s->log_replayed_on_open) {
2158        result->corruptions_fixed++;
2159    }
2160
2161    vhdx_check_bat_entries(bs, &result->corruptions);
2162
2163    return 0;
2164}
2165
2166static int vhdx_has_zero_init(BlockDriverState *bs)
2167{
2168    BDRVVHDXState *s = bs->opaque;
2169    int state;
2170
2171    /*
2172     * Check the subformat: Fixed images have all BAT entries present,
2173     * dynamic images have none (right after creation).  It is
2174     * therefore enough to check the first BAT entry.
2175     */
2176    if (!s->bat_entries) {
2177        return 1;
2178    }
2179
2180    state = s->bat[0] & VHDX_BAT_STATE_BIT_MASK;
2181    if (state == PAYLOAD_BLOCK_FULLY_PRESENT) {
2182        /* Fixed subformat */
2183        return bdrv_has_zero_init(bs->file->bs);
2184    }
2185
2186    /* Dynamic subformat */
2187    return 1;
2188}
2189
2190static QemuOptsList vhdx_create_opts = {
2191    .name = "vhdx-create-opts",
2192    .head = QTAILQ_HEAD_INITIALIZER(vhdx_create_opts.head),
2193    .desc = {
2194        {
2195           .name = BLOCK_OPT_SIZE,
2196           .type = QEMU_OPT_SIZE,
2197           .help = "Virtual disk size; max of 64TB."
2198       },
2199       {
2200           .name = VHDX_BLOCK_OPT_LOG_SIZE,
2201           .type = QEMU_OPT_SIZE,
2202           .def_value_str = stringify(DEFAULT_LOG_SIZE),
2203           .help = "Log size; min 1MB."
2204       },
2205       {
2206           .name = VHDX_BLOCK_OPT_BLOCK_SIZE,
2207           .type = QEMU_OPT_SIZE,
2208           .def_value_str = stringify(0),
2209           .help = "Block Size; min 1MB, max 256MB. " \
2210                   "0 means auto-calculate based on image size."
2211       },
2212       {
2213           .name = BLOCK_OPT_SUBFMT,
2214           .type = QEMU_OPT_STRING,
2215           .help = "VHDX format type, can be either 'dynamic' or 'fixed'. "\
2216                   "Default is 'dynamic'."
2217       },
2218       {
2219           .name = VHDX_BLOCK_OPT_ZERO,
2220           .type = QEMU_OPT_BOOL,
2221           .help = "Force use of payload blocks of type 'ZERO'. "\
2222                   "Non-standard, but default.  Do not set to 'off' when "\
2223                   "using 'qemu-img convert' with subformat=dynamic."
2224       },
2225       { NULL }
2226    }
2227};
2228
2229static BlockDriver bdrv_vhdx = {
2230    .format_name            = "vhdx",
2231    .instance_size          = sizeof(BDRVVHDXState),
2232    .bdrv_probe             = vhdx_probe,
2233    .bdrv_open              = vhdx_open,
2234    .bdrv_close             = vhdx_close,
2235    .bdrv_reopen_prepare    = vhdx_reopen_prepare,
2236    .bdrv_child_perm        = bdrv_format_default_perms,
2237    .bdrv_co_readv          = vhdx_co_readv,
2238    .bdrv_co_writev         = vhdx_co_writev,
2239    .bdrv_co_create         = vhdx_co_create,
2240    .bdrv_co_create_opts    = vhdx_co_create_opts,
2241    .bdrv_get_info          = vhdx_get_info,
2242    .bdrv_co_check          = vhdx_co_check,
2243    .bdrv_has_zero_init     = vhdx_has_zero_init,
2244
2245    .create_opts            = &vhdx_create_opts,
2246};
2247
2248static void bdrv_vhdx_init(void)
2249{
2250    bdrv_register(&bdrv_vhdx);
2251}
2252
2253block_init(bdrv_vhdx_init);
2254