xref: /openbmc/qemu/block/vhdx.c (revision ad6ef0a42e314a8c6ac6c96d5f6e607a1e5644b5)
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 "qemu/memalign.h"
29  #include "vhdx.h"
30  #include "migration/blocker.h"
31  #include "qemu/uuid.h"
32  #include "qapi/qmp/qdict.h"
33  #include "qapi/qobject-input-visitor.h"
34  #include "qapi/qapi-visit-block-core.h"
35  
36  /* Options for VHDX creation */
37  
38  #define VHDX_BLOCK_OPT_LOG_SIZE   "log_size"
39  #define VHDX_BLOCK_OPT_BLOCK_SIZE "block_size"
40  #define VHDX_BLOCK_OPT_ZERO "block_state_zero"
41  
42  typedef enum VHDXImageType {
43      VHDX_TYPE_DYNAMIC = 0,
44      VHDX_TYPE_FIXED,
45      VHDX_TYPE_DIFFERENCING,   /* Currently unsupported */
46  } VHDXImageType;
47  
48  static QemuOptsList vhdx_create_opts;
49  
50  /* Several metadata and region table data entries are identified by
51   * guids in  a MS-specific GUID format. */
52  
53  
54  /* ------- Known Region Table GUIDs ---------------------- */
55  static const MSGUID bat_guid =      { .data1 = 0x2dc27766,
56                                        .data2 = 0xf623,
57                                        .data3 = 0x4200,
58                                        .data4 = { 0x9d, 0x64, 0x11, 0x5e,
59                                                   0x9b, 0xfd, 0x4a, 0x08} };
60  
61  static const MSGUID metadata_guid = { .data1 = 0x8b7ca206,
62                                        .data2 = 0x4790,
63                                        .data3 = 0x4b9a,
64                                        .data4 = { 0xb8, 0xfe, 0x57, 0x5f,
65                                                   0x05, 0x0f, 0x88, 0x6e} };
66  
67  
68  
69  /* ------- Known Metadata Entry GUIDs ---------------------- */
70  static const MSGUID file_param_guid =   { .data1 = 0xcaa16737,
71                                            .data2 = 0xfa36,
72                                            .data3 = 0x4d43,
73                                            .data4 = { 0xb3, 0xb6, 0x33, 0xf0,
74                                                       0xaa, 0x44, 0xe7, 0x6b} };
75  
76  static const MSGUID virtual_size_guid = { .data1 = 0x2FA54224,
77                                            .data2 = 0xcd1b,
78                                            .data3 = 0x4876,
79                                            .data4 = { 0xb2, 0x11, 0x5d, 0xbe,
80                                                       0xd8, 0x3b, 0xf4, 0xb8} };
81  
82  static const MSGUID page83_guid =       { .data1 = 0xbeca12ab,
83                                            .data2 = 0xb2e6,
84                                            .data3 = 0x4523,
85                                            .data4 = { 0x93, 0xef, 0xc3, 0x09,
86                                                       0xe0, 0x00, 0xc7, 0x46} };
87  
88  
89  static const MSGUID phys_sector_guid =  { .data1 = 0xcda348c7,
90                                            .data2 = 0x445d,
91                                            .data3 = 0x4471,
92                                            .data4 = { 0x9c, 0xc9, 0xe9, 0x88,
93                                                       0x52, 0x51, 0xc5, 0x56} };
94  
95  static const MSGUID parent_locator_guid = { .data1 = 0xa8d35f2d,
96                                              .data2 = 0xb30b,
97                                              .data3 = 0x454d,
98                                              .data4 = { 0xab, 0xf7, 0xd3,
99                                                         0xd8, 0x48, 0x34,
100                                                         0xab, 0x0c} };
101  
102  static const MSGUID logical_sector_guid = { .data1 = 0x8141bf1d,
103                                              .data2 = 0xa96f,
104                                              .data3 = 0x4709,
105                                              .data4 = { 0xba, 0x47, 0xf2,
106                                                         0x33, 0xa8, 0xfa,
107                                                         0xab, 0x5f} };
108  
109  /* Each parent type must have a valid GUID; this is for parent images
110   * of type 'VHDX'.  If we were to allow e.g. a QCOW2 parent, we would
111   * need to make up our own QCOW2 GUID type */
112  static const MSGUID parent_vhdx_guid __attribute__((unused))
113                                       = { .data1 = 0xb04aefb7,
114                                           .data2 = 0xd19e,
115                                           .data3 = 0x4a81,
116                                           .data4 = { 0xb7, 0x89, 0x25, 0xb8,
117                                                      0xe9, 0x44, 0x59, 0x13} };
118  
119  
120  #define META_FILE_PARAMETER_PRESENT      0x01
121  #define META_VIRTUAL_DISK_SIZE_PRESENT   0x02
122  #define META_PAGE_83_PRESENT             0x04
123  #define META_LOGICAL_SECTOR_SIZE_PRESENT 0x08
124  #define META_PHYS_SECTOR_SIZE_PRESENT    0x10
125  #define META_PARENT_LOCATOR_PRESENT      0x20
126  
127  #define META_ALL_PRESENT    \
128      (META_FILE_PARAMETER_PRESENT | META_VIRTUAL_DISK_SIZE_PRESENT | \
129       META_PAGE_83_PRESENT | META_LOGICAL_SECTOR_SIZE_PRESENT | \
130       META_PHYS_SECTOR_SIZE_PRESENT)
131  
132  
133  typedef struct VHDXSectorInfo {
134      uint32_t bat_idx;       /* BAT entry index */
135      uint32_t sectors_avail; /* sectors available in payload block */
136      uint32_t bytes_left;    /* bytes left in the block after data to r/w */
137      uint32_t bytes_avail;   /* bytes available in payload block */
138      uint64_t file_offset;   /* absolute offset in bytes, in file */
139      uint64_t block_offset;  /* block offset, in bytes */
140  } VHDXSectorInfo;
141  
142  /* Calculates new checksum.
143   *
144   * Zero is substituted during crc calculation for the original crc field
145   * crc_offset: byte offset in buf of the buffer crc
146   * buf: buffer pointer
147   * size: size of buffer (must be > crc_offset+4)
148   *
149   * Note: The buffer should have all multi-byte data in little-endian format,
150   *       and the resulting checksum is in little endian format.
151   */
vhdx_update_checksum(uint8_t * buf,size_t size,int crc_offset)152  uint32_t vhdx_update_checksum(uint8_t *buf, size_t size, int crc_offset)
153  {
154      uint32_t crc;
155  
156      assert(buf != NULL);
157      assert(size > (crc_offset + sizeof(crc)));
158  
159      memset(buf + crc_offset, 0, sizeof(crc));
160      crc =  crc32c(0xffffffff, buf, size);
161      crc = cpu_to_le32(crc);
162      memcpy(buf + crc_offset, &crc, sizeof(crc));
163  
164      return crc;
165  }
166  
vhdx_checksum_calc(uint32_t crc,uint8_t * buf,size_t size,int crc_offset)167  uint32_t vhdx_checksum_calc(uint32_t crc, uint8_t *buf, size_t size,
168                              int crc_offset)
169  {
170      uint32_t crc_new;
171      uint32_t crc_orig;
172      assert(buf != NULL);
173  
174      if (crc_offset > 0) {
175          memcpy(&crc_orig, buf + crc_offset, sizeof(crc_orig));
176          memset(buf + crc_offset, 0, sizeof(crc_orig));
177      }
178  
179      crc_new = crc32c(crc, buf, size);
180      if (crc_offset > 0) {
181          memcpy(buf + crc_offset, &crc_orig, sizeof(crc_orig));
182      }
183  
184      return crc_new;
185  }
186  
187  /* Validates the checksum of the buffer, with an in-place CRC.
188   *
189   * Zero is substituted during crc calculation for the original crc field,
190   * and the crc field is restored afterwards.  But the buffer will be modified
191   * during the calculation, so this may not be not suitable for multi-threaded
192   * use.
193   *
194   * crc_offset: byte offset in buf of the buffer crc
195   * buf: buffer pointer
196   * size: size of buffer (must be > crc_offset+4)
197   *
198   * returns true if checksum is valid, false otherwise
199   */
vhdx_checksum_is_valid(uint8_t * buf,size_t size,int crc_offset)200  bool vhdx_checksum_is_valid(uint8_t *buf, size_t size, int crc_offset)
201  {
202      uint32_t crc_orig;
203      uint32_t crc;
204  
205      assert(buf != NULL);
206      assert(size > (crc_offset + 4));
207  
208      memcpy(&crc_orig, buf + crc_offset, sizeof(crc_orig));
209      crc_orig = le32_to_cpu(crc_orig);
210  
211      crc = vhdx_checksum_calc(0xffffffff, buf, size, crc_offset);
212  
213      return crc == crc_orig;
214  }
215  
216  
217  /*
218   * This generates a UUID that is compliant with the MS GUIDs used
219   * in the VHDX spec (and elsewhere).
220   */
vhdx_guid_generate(MSGUID * guid)221  void vhdx_guid_generate(MSGUID *guid)
222  {
223      QemuUUID uuid;
224      assert(guid != NULL);
225  
226      qemu_uuid_generate(&uuid);
227      memcpy(guid, &uuid, sizeof(MSGUID));
228  }
229  
230  /* Check for region overlaps inside the VHDX image */
vhdx_region_check(BDRVVHDXState * s,uint64_t start,uint64_t length)231  static int vhdx_region_check(BDRVVHDXState *s, uint64_t start, uint64_t length)
232  {
233      int ret = 0;
234      uint64_t end;
235      VHDXRegionEntry *r;
236  
237      end = start + length;
238      QLIST_FOREACH(r, &s->regions, entries) {
239          if (!((start >= r->end) || (end <= r->start))) {
240              error_report("VHDX region %" PRIu64 "-%" PRIu64 " overlaps with "
241                           "region %" PRIu64 "-%." PRIu64, start, end, r->start,
242                           r->end);
243              ret = -EINVAL;
244              goto exit;
245          }
246      }
247  
248  exit:
249      return ret;
250  }
251  
252  /* Register a region for future checks */
vhdx_region_register(BDRVVHDXState * s,uint64_t start,uint64_t length)253  static void vhdx_region_register(BDRVVHDXState *s,
254                                   uint64_t start, uint64_t length)
255  {
256      VHDXRegionEntry *r;
257  
258      r = g_malloc0(sizeof(*r));
259  
260      r->start = start;
261      r->end = start + length;
262  
263      QLIST_INSERT_HEAD(&s->regions, r, entries);
264  }
265  
266  /* Free all registered regions */
vhdx_region_unregister_all(BDRVVHDXState * s)267  static void vhdx_region_unregister_all(BDRVVHDXState *s)
268  {
269      VHDXRegionEntry *r, *r_next;
270  
271      QLIST_FOREACH_SAFE(r, &s->regions, entries, r_next) {
272          QLIST_REMOVE(r, entries);
273          g_free(r);
274      }
275  }
276  
vhdx_set_shift_bits(BDRVVHDXState * s)277  static void vhdx_set_shift_bits(BDRVVHDXState *s)
278  {
279      s->logical_sector_size_bits = ctz32(s->logical_sector_size);
280      s->sectors_per_block_bits =   ctz32(s->sectors_per_block);
281      s->chunk_ratio_bits =         ctz64(s->chunk_ratio);
282      s->block_size_bits =          ctz32(s->block_size);
283  }
284  
285  /*
286   * Per the MS VHDX Specification, for every VHDX file:
287   *      - The header section is fixed size - 1 MB
288   *      - The header section is always the first "object"
289   *      - The first 64KB of the header is the File Identifier
290   *      - The first uint64 (8 bytes) is the VHDX Signature ("vhdxfile")
291   *      - The following 512 bytes constitute a UTF-16 string identifiying the
292   *        software that created the file, and is optional and diagnostic only.
293   *
294   *  Therefore, we probe by looking for the vhdxfile signature "vhdxfile"
295   */
vhdx_probe(const uint8_t * buf,int buf_size,const char * filename)296  static int vhdx_probe(const uint8_t *buf, int buf_size, const char *filename)
297  {
298      if (buf_size >= 8 && !memcmp(buf, "vhdxfile", 8)) {
299          return 100;
300      }
301      return 0;
302  }
303  
304  /*
305   * Writes the header to the specified offset.
306   *
307   * This will optionally read in buffer data from disk (otherwise zero-fill),
308   * and then update the header checksum.  Header is converted to proper
309   * endianness before being written to the specified file offset
310   */
vhdx_write_header(BdrvChild * file,VHDXHeader * hdr,uint64_t offset,bool read)311  static int vhdx_write_header(BdrvChild *file, VHDXHeader *hdr,
312                               uint64_t offset, bool read)
313  {
314      BlockDriverState *bs_file = file->bs;
315      uint8_t *buffer = NULL;
316      int ret;
317      VHDXHeader *header_le;
318  
319      assert(bs_file != NULL);
320      assert(hdr != NULL);
321  
322      /* the header checksum is not over just the packed size of VHDXHeader,
323       * but rather over the entire 'reserved' range for the header, which is
324       * 4KB (VHDX_HEADER_SIZE). */
325  
326      buffer = qemu_blockalign(bs_file, VHDX_HEADER_SIZE);
327      if (read) {
328          /* if true, we can't assume the extra reserved bytes are 0 */
329          ret = bdrv_pread(file, offset, VHDX_HEADER_SIZE, buffer, 0);
330          if (ret < 0) {
331              goto exit;
332          }
333      } else {
334          memset(buffer, 0, VHDX_HEADER_SIZE);
335      }
336  
337      /* overwrite the actual VHDXHeader portion */
338      header_le = (VHDXHeader *)buffer;
339      memcpy(header_le, hdr, sizeof(VHDXHeader));
340      vhdx_header_le_export(hdr, header_le);
341      vhdx_update_checksum(buffer, VHDX_HEADER_SIZE,
342                           offsetof(VHDXHeader, checksum));
343      ret = bdrv_pwrite_sync(file, offset, sizeof(VHDXHeader), header_le, 0);
344  
345  exit:
346      qemu_vfree(buffer);
347      return ret;
348  }
349  
350  /* Update the VHDX headers
351   *
352   * This follows the VHDX spec procedures for header updates.
353   *
354   *  - non-current header is updated with largest sequence number
355   */
356  static int GRAPH_RDLOCK
vhdx_update_header(BlockDriverState * bs,BDRVVHDXState * s,bool generate_data_write_guid,MSGUID * log_guid)357  vhdx_update_header(BlockDriverState *bs, BDRVVHDXState *s,
358                     bool generate_data_write_guid, MSGUID *log_guid)
359  {
360      int ret = 0;
361      int hdr_idx = 0;
362      uint64_t header_offset = VHDX_HEADER1_OFFSET;
363  
364      VHDXHeader *active_header;
365      VHDXHeader *inactive_header;
366  
367      /* operate on the non-current header */
368      if (s->curr_header == 0) {
369          hdr_idx = 1;
370          header_offset = VHDX_HEADER2_OFFSET;
371      }
372  
373      active_header   = s->headers[s->curr_header];
374      inactive_header = s->headers[hdr_idx];
375  
376      inactive_header->sequence_number = active_header->sequence_number + 1;
377  
378      /* a new file guid must be generated before any file write, including
379       * headers */
380      inactive_header->file_write_guid = s->session_guid;
381  
382      /* a new data guid only needs to be generated before any guest-visible
383       * writes (i.e. something observable via virtual disk read) */
384      if (generate_data_write_guid) {
385          vhdx_guid_generate(&inactive_header->data_write_guid);
386      }
387  
388      /* update the log guid if present */
389      if (log_guid) {
390          inactive_header->log_guid = *log_guid;
391      }
392  
393      ret = vhdx_write_header(bs->file, inactive_header, header_offset, true);
394      if (ret < 0) {
395          goto exit;
396      }
397      s->curr_header = hdr_idx;
398  
399  exit:
400      return ret;
401  }
402  
403  /*
404   * The VHDX spec calls for header updates to be performed twice, so that both
405   * the current and non-current header have valid info
406   */
vhdx_update_headers(BlockDriverState * bs,BDRVVHDXState * s,bool generate_data_write_guid,MSGUID * log_guid)407  int vhdx_update_headers(BlockDriverState *bs, BDRVVHDXState *s,
408                          bool generate_data_write_guid, MSGUID *log_guid)
409  {
410      int ret;
411  
412      ret = vhdx_update_header(bs, s, generate_data_write_guid, log_guid);
413      if (ret < 0) {
414          return ret;
415      }
416      return vhdx_update_header(bs, s, generate_data_write_guid, log_guid);
417  }
418  
419  /* opens the specified header block from the VHDX file header section */
420  static void GRAPH_RDLOCK
vhdx_parse_header(BlockDriverState * bs,BDRVVHDXState * s,Error ** errp)421  vhdx_parse_header(BlockDriverState *bs, BDRVVHDXState *s, Error **errp)
422  {
423      int ret;
424      VHDXHeader *header1;
425      VHDXHeader *header2;
426      bool h1_valid = false;
427      bool h2_valid = false;
428      uint64_t h1_seq = 0;
429      uint64_t h2_seq = 0;
430      uint8_t *buffer;
431  
432      /* header1 & header2 are freed in vhdx_close() */
433      header1 = qemu_blockalign(bs, sizeof(VHDXHeader));
434      header2 = qemu_blockalign(bs, sizeof(VHDXHeader));
435  
436      buffer = qemu_blockalign(bs, VHDX_HEADER_SIZE);
437  
438      s->headers[0] = header1;
439      s->headers[1] = header2;
440  
441      /* We have to read the whole VHDX_HEADER_SIZE instead of
442       * sizeof(VHDXHeader), because the checksum is over the whole
443       * region */
444      ret = bdrv_pread(bs->file, VHDX_HEADER1_OFFSET, VHDX_HEADER_SIZE, buffer,
445                       0);
446      if (ret < 0) {
447          goto fail;
448      }
449      /* copy over just the relevant portion that we need */
450      memcpy(header1, buffer, sizeof(VHDXHeader));
451  
452      if (vhdx_checksum_is_valid(buffer, VHDX_HEADER_SIZE, 4)) {
453          vhdx_header_le_import(header1);
454          if (header1->signature == VHDX_HEADER_SIGNATURE &&
455              header1->version == 1) {
456              h1_seq = header1->sequence_number;
457              h1_valid = true;
458          }
459      }
460  
461      ret = bdrv_pread(bs->file, VHDX_HEADER2_OFFSET, VHDX_HEADER_SIZE, buffer,
462                       0);
463      if (ret < 0) {
464          goto fail;
465      }
466      /* copy over just the relevant portion that we need */
467      memcpy(header2, buffer, sizeof(VHDXHeader));
468  
469      if (vhdx_checksum_is_valid(buffer, VHDX_HEADER_SIZE, 4)) {
470          vhdx_header_le_import(header2);
471          if (header2->signature == VHDX_HEADER_SIGNATURE &&
472              header2->version == 1) {
473              h2_seq = header2->sequence_number;
474              h2_valid = true;
475          }
476      }
477  
478      /* If there is only 1 valid header (or no valid headers), we
479       * don't care what the sequence numbers are */
480      if (h1_valid && !h2_valid) {
481          s->curr_header = 0;
482      } else if (!h1_valid && h2_valid) {
483          s->curr_header = 1;
484      } else if (!h1_valid && !h2_valid) {
485          goto fail;
486      } else {
487          /* If both headers are valid, then we choose the active one by the
488           * highest sequence number.  If the sequence numbers are equal, that is
489           * invalid */
490          if (h1_seq > h2_seq) {
491              s->curr_header = 0;
492          } else if (h2_seq > h1_seq) {
493              s->curr_header = 1;
494          } else {
495              /* The Microsoft Disk2VHD tool will create 2 identical
496               * headers, with identical sequence numbers.  If the headers are
497               * identical, don't consider the file corrupt */
498              if (!memcmp(header1, header2, sizeof(VHDXHeader))) {
499                  s->curr_header = 0;
500              } else {
501                  goto fail;
502              }
503          }
504      }
505  
506      vhdx_region_register(s, s->headers[s->curr_header]->log_offset,
507                              s->headers[s->curr_header]->log_length);
508      goto exit;
509  
510  fail:
511      error_setg_errno(errp, -ret, "No valid VHDX header found");
512      qemu_vfree(header1);
513      qemu_vfree(header2);
514      s->headers[0] = NULL;
515      s->headers[1] = NULL;
516  exit:
517      qemu_vfree(buffer);
518  }
519  
520  
521  static int GRAPH_RDLOCK
vhdx_open_region_tables(BlockDriverState * bs,BDRVVHDXState * s)522  vhdx_open_region_tables(BlockDriverState *bs, BDRVVHDXState *s)
523  {
524      int ret = 0;
525      uint8_t *buffer;
526      int offset = 0;
527      VHDXRegionTableEntry rt_entry;
528      uint32_t i;
529      bool bat_rt_found = false;
530      bool metadata_rt_found = false;
531  
532      /* We have to read the whole 64KB block, because the crc32 is over the
533       * whole block */
534      buffer = qemu_blockalign(bs, VHDX_HEADER_BLOCK_SIZE);
535  
536      ret = bdrv_pread(bs->file, VHDX_REGION_TABLE_OFFSET,
537                       VHDX_HEADER_BLOCK_SIZE, buffer, 0);
538      if (ret < 0) {
539          goto fail;
540      }
541      memcpy(&s->rt, buffer, sizeof(s->rt));
542      offset += sizeof(s->rt);
543  
544      if (!vhdx_checksum_is_valid(buffer, VHDX_HEADER_BLOCK_SIZE, 4)) {
545          ret = -EINVAL;
546          goto fail;
547      }
548  
549      vhdx_region_header_le_import(&s->rt);
550  
551      if (s->rt.signature != VHDX_REGION_SIGNATURE) {
552          ret = -EINVAL;
553          goto fail;
554      }
555  
556  
557      /* Per spec, maximum region table entry count is 2047 */
558      if (s->rt.entry_count > 2047) {
559          ret = -EINVAL;
560          goto fail;
561      }
562  
563      for (i = 0; i < s->rt.entry_count; i++) {
564          memcpy(&rt_entry, buffer + offset, sizeof(rt_entry));
565          offset += sizeof(rt_entry);
566  
567          vhdx_region_entry_le_import(&rt_entry);
568  
569          /* check for region overlap between these entries, and any
570           * other memory regions in the file */
571          ret = vhdx_region_check(s, rt_entry.file_offset, rt_entry.length);
572          if (ret < 0) {
573              goto fail;
574          }
575  
576          vhdx_region_register(s, rt_entry.file_offset, rt_entry.length);
577  
578          /* see if we recognize the entry */
579          if (guid_eq(rt_entry.guid, bat_guid)) {
580              /* must be unique; if we have already found it this is invalid */
581              if (bat_rt_found) {
582                  ret = -EINVAL;
583                  goto fail;
584              }
585              bat_rt_found = true;
586              s->bat_rt = rt_entry;
587              continue;
588          }
589  
590          if (guid_eq(rt_entry.guid, metadata_guid)) {
591              /* must be unique; if we have already found it this is invalid */
592              if (metadata_rt_found) {
593                  ret = -EINVAL;
594                  goto fail;
595              }
596              metadata_rt_found = true;
597              s->metadata_rt = rt_entry;
598              continue;
599          }
600  
601          if (rt_entry.data_bits & VHDX_REGION_ENTRY_REQUIRED) {
602              /* cannot read vhdx file - required region table entry that
603               * we do not understand.  per spec, we must fail to open */
604              ret = -ENOTSUP;
605              goto fail;
606          }
607      }
608  
609      if (!bat_rt_found || !metadata_rt_found) {
610          ret = -EINVAL;
611          goto fail;
612      }
613  
614      ret = 0;
615  
616  fail:
617      qemu_vfree(buffer);
618      return ret;
619  }
620  
621  
622  
623  /* Metadata initial parser
624   *
625   * This loads all the metadata entry fields.  This may cause additional
626   * fields to be processed (e.g. parent locator, etc..).
627   *
628   * There are 5 Metadata items that are always required:
629   *      - File Parameters (block size, has a parent)
630   *      - Virtual Disk Size (size, in bytes, of the virtual drive)
631   *      - Page 83 Data (scsi page 83 guid)
632   *      - Logical Sector Size (logical sector size in bytes, either 512 or
633   *                             4096.  We only support 512 currently)
634   *      - Physical Sector Size (512 or 4096)
635   *
636   * Also, if the File Parameters indicate this is a differencing file,
637   * we must also look for the Parent Locator metadata item.
638   */
639  static int GRAPH_RDLOCK
vhdx_parse_metadata(BlockDriverState * bs,BDRVVHDXState * s)640  vhdx_parse_metadata(BlockDriverState *bs, BDRVVHDXState *s)
641  {
642      int ret = 0;
643      uint8_t *buffer;
644      int offset = 0;
645      uint32_t i = 0;
646      VHDXMetadataTableEntry md_entry;
647  
648      buffer = qemu_blockalign(bs, VHDX_METADATA_TABLE_MAX_SIZE);
649  
650      ret = bdrv_pread(bs->file, s->metadata_rt.file_offset,
651                       VHDX_METADATA_TABLE_MAX_SIZE, buffer, 0);
652      if (ret < 0) {
653          goto exit;
654      }
655      memcpy(&s->metadata_hdr, buffer, sizeof(s->metadata_hdr));
656      offset += sizeof(s->metadata_hdr);
657  
658      vhdx_metadata_header_le_import(&s->metadata_hdr);
659  
660      if (s->metadata_hdr.signature != VHDX_METADATA_SIGNATURE) {
661          ret = -EINVAL;
662          goto exit;
663      }
664  
665      s->metadata_entries.present = 0;
666  
667      if ((s->metadata_hdr.entry_count * sizeof(md_entry)) >
668          (VHDX_METADATA_TABLE_MAX_SIZE - offset)) {
669          ret = -EINVAL;
670          goto exit;
671      }
672  
673      for (i = 0; i < s->metadata_hdr.entry_count; i++) {
674          memcpy(&md_entry, buffer + offset, sizeof(md_entry));
675          offset += sizeof(md_entry);
676  
677          vhdx_metadata_entry_le_import(&md_entry);
678  
679          if (guid_eq(md_entry.item_id, file_param_guid)) {
680              if (s->metadata_entries.present & META_FILE_PARAMETER_PRESENT) {
681                  ret = -EINVAL;
682                  goto exit;
683              }
684              s->metadata_entries.file_parameters_entry = md_entry;
685              s->metadata_entries.present |= META_FILE_PARAMETER_PRESENT;
686              continue;
687          }
688  
689          if (guid_eq(md_entry.item_id, virtual_size_guid)) {
690              if (s->metadata_entries.present & META_VIRTUAL_DISK_SIZE_PRESENT) {
691                  ret = -EINVAL;
692                  goto exit;
693              }
694              s->metadata_entries.virtual_disk_size_entry = md_entry;
695              s->metadata_entries.present |= META_VIRTUAL_DISK_SIZE_PRESENT;
696              continue;
697          }
698  
699          if (guid_eq(md_entry.item_id, page83_guid)) {
700              if (s->metadata_entries.present & META_PAGE_83_PRESENT) {
701                  ret = -EINVAL;
702                  goto exit;
703              }
704              s->metadata_entries.page83_data_entry = md_entry;
705              s->metadata_entries.present |= META_PAGE_83_PRESENT;
706              continue;
707          }
708  
709          if (guid_eq(md_entry.item_id, logical_sector_guid)) {
710              if (s->metadata_entries.present &
711                  META_LOGICAL_SECTOR_SIZE_PRESENT) {
712                  ret = -EINVAL;
713                  goto exit;
714              }
715              s->metadata_entries.logical_sector_size_entry = md_entry;
716              s->metadata_entries.present |= META_LOGICAL_SECTOR_SIZE_PRESENT;
717              continue;
718          }
719  
720          if (guid_eq(md_entry.item_id, phys_sector_guid)) {
721              if (s->metadata_entries.present & META_PHYS_SECTOR_SIZE_PRESENT) {
722                  ret = -EINVAL;
723                  goto exit;
724              }
725              s->metadata_entries.phys_sector_size_entry = md_entry;
726              s->metadata_entries.present |= META_PHYS_SECTOR_SIZE_PRESENT;
727              continue;
728          }
729  
730          if (guid_eq(md_entry.item_id, parent_locator_guid)) {
731              if (s->metadata_entries.present & META_PARENT_LOCATOR_PRESENT) {
732                  ret = -EINVAL;
733                  goto exit;
734              }
735              s->metadata_entries.parent_locator_entry = md_entry;
736              s->metadata_entries.present |= META_PARENT_LOCATOR_PRESENT;
737              continue;
738          }
739  
740          if (md_entry.data_bits & VHDX_META_FLAGS_IS_REQUIRED) {
741              /* cannot read vhdx file - required region table entry that
742               * we do not understand.  per spec, we must fail to open */
743              ret = -ENOTSUP;
744              goto exit;
745          }
746      }
747  
748      if (s->metadata_entries.present != META_ALL_PRESENT) {
749          ret = -ENOTSUP;
750          goto exit;
751      }
752  
753      ret = bdrv_pread(bs->file,
754                       s->metadata_entries.file_parameters_entry.offset
755                                           + s->metadata_rt.file_offset,
756                       sizeof(s->params),
757                       &s->params,
758                       0);
759  
760      if (ret < 0) {
761          goto exit;
762      }
763  
764      s->params.block_size = le32_to_cpu(s->params.block_size);
765      s->params.data_bits = le32_to_cpu(s->params.data_bits);
766  
767  
768      /* We now have the file parameters, so we can tell if this is a
769       * differencing file (i.e.. has_parent), is dynamic or fixed
770       * sized (leave_blocks_allocated), and the block size */
771  
772      /* The parent locator required iff the file parameters has_parent set */
773      if (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) {
774          if (s->metadata_entries.present & META_PARENT_LOCATOR_PRESENT) {
775              /* TODO: parse  parent locator fields */
776              ret = -ENOTSUP; /* temp, until differencing files are supported */
777              goto exit;
778          } else {
779              /* if has_parent is set, but there is not parent locator present,
780               * then that is an invalid combination */
781              ret = -EINVAL;
782              goto exit;
783          }
784      }
785  
786      /* determine virtual disk size, logical sector size,
787       * and phys sector size */
788  
789      ret = bdrv_pread(bs->file,
790                       s->metadata_entries.virtual_disk_size_entry.offset
791                                             + s->metadata_rt.file_offset,
792                       sizeof(uint64_t),
793                       &s->virtual_disk_size,
794                       0);
795      if (ret < 0) {
796          goto exit;
797      }
798      ret = bdrv_pread(bs->file,
799                       s->metadata_entries.logical_sector_size_entry.offset
800                                               + s->metadata_rt.file_offset,
801                       sizeof(uint32_t),
802                       &s->logical_sector_size,
803                       0);
804      if (ret < 0) {
805          goto exit;
806      }
807      ret = bdrv_pread(bs->file,
808                       s->metadata_entries.phys_sector_size_entry.offset
809                                            + s->metadata_rt.file_offset,
810                       sizeof(uint32_t),
811                       &s->physical_sector_size,
812                       0);
813      if (ret < 0) {
814          goto exit;
815      }
816  
817      s->virtual_disk_size = le64_to_cpu(s->virtual_disk_size);
818      s->logical_sector_size = le32_to_cpu(s->logical_sector_size);
819      s->physical_sector_size = le32_to_cpu(s->physical_sector_size);
820  
821      if (s->params.block_size < VHDX_BLOCK_SIZE_MIN ||
822          s->params.block_size > VHDX_BLOCK_SIZE_MAX) {
823          ret = -EINVAL;
824          goto exit;
825      }
826  
827      /* Currently we only support 512 */
828      if (s->logical_sector_size != 512) {
829          ret = -ENOTSUP;
830          goto exit;
831      }
832  
833      /* Both block_size and sector_size are guaranteed powers of 2, below.
834         Due to range checks above, s->sectors_per_block can never be < 256 */
835      s->sectors_per_block = s->params.block_size / s->logical_sector_size;
836      s->chunk_ratio = (VHDX_MAX_SECTORS_PER_BLOCK) *
837                       (uint64_t)s->logical_sector_size /
838                       (uint64_t)s->params.block_size;
839  
840      /* These values are ones we will want to use for division / multiplication
841       * later on, and they are all guaranteed (per the spec) to be powers of 2,
842       * so we can take advantage of that for shift operations during
843       * reads/writes */
844      if (s->logical_sector_size & (s->logical_sector_size - 1)) {
845          ret = -EINVAL;
846          goto exit;
847      }
848      if (s->sectors_per_block & (s->sectors_per_block - 1)) {
849          ret = -EINVAL;
850          goto exit;
851      }
852      if (s->chunk_ratio & (s->chunk_ratio - 1)) {
853          ret = -EINVAL;
854          goto exit;
855      }
856      s->block_size = s->params.block_size;
857      if (s->block_size & (s->block_size - 1)) {
858          ret = -EINVAL;
859          goto exit;
860      }
861  
862      vhdx_set_shift_bits(s);
863  
864      ret = 0;
865  
866  exit:
867      qemu_vfree(buffer);
868      return ret;
869  }
870  
871  /*
872   * Calculate the number of BAT entries, including sector
873   * bitmap entries.
874   */
vhdx_calc_bat_entries(BDRVVHDXState * s)875  static void vhdx_calc_bat_entries(BDRVVHDXState *s)
876  {
877      uint32_t data_blocks_cnt, bitmap_blocks_cnt;
878  
879      data_blocks_cnt = DIV_ROUND_UP(s->virtual_disk_size, s->block_size);
880      bitmap_blocks_cnt = DIV_ROUND_UP(data_blocks_cnt, s->chunk_ratio);
881  
882      if (s->parent_entries) {
883          s->bat_entries = bitmap_blocks_cnt * (s->chunk_ratio + 1);
884      } else {
885          s->bat_entries = data_blocks_cnt +
886                           ((data_blocks_cnt - 1) >> s->chunk_ratio_bits);
887      }
888  
889  }
890  
891  static int coroutine_mixed_fn GRAPH_RDLOCK
vhdx_check_bat_entries(BlockDriverState * bs,int * errcnt)892  vhdx_check_bat_entries(BlockDriverState *bs, int *errcnt)
893  {
894      BDRVVHDXState *s = bs->opaque;
895      int64_t image_file_size = bdrv_getlength(bs->file->bs);
896      uint64_t payblocks = s->chunk_ratio;
897      uint64_t i;
898      int ret = 0;
899  
900      if (image_file_size < 0) {
901          error_report("Could not determinate VHDX image file size.");
902          return image_file_size;
903      }
904  
905      for (i = 0; i < s->bat_entries; i++) {
906          if ((s->bat[i] & VHDX_BAT_STATE_BIT_MASK) ==
907              PAYLOAD_BLOCK_FULLY_PRESENT) {
908              uint64_t offset = s->bat[i] & VHDX_BAT_FILE_OFF_MASK;
909              /*
910               * Allow that the last block exists only partially. The VHDX spec
911               * states that the image file can only grow in blocksize increments,
912               * but QEMU created images with partial last blocks in the past.
913               */
914              uint32_t block_length = MIN(s->block_size,
915                  bs->total_sectors * BDRV_SECTOR_SIZE - i * s->block_size);
916              /*
917               * Check for BAT entry overflow.
918               */
919              if (offset > INT64_MAX - s->block_size) {
920                  error_report("VHDX BAT entry %" PRIu64 " offset overflow.", i);
921                  ret = -EINVAL;
922                  if (!errcnt) {
923                      break;
924                  }
925                  (*errcnt)++;
926              }
927              /*
928               * Check if fully allocated BAT entries do not reside after
929               * end of the image file.
930               */
931              if (offset >= image_file_size) {
932                  error_report("VHDX BAT entry %" PRIu64 " start offset %" PRIu64
933                               " points after end of file (%" PRIi64 "). Image"
934                               " has probably been truncated.",
935                               i, offset, image_file_size);
936                  ret = -EINVAL;
937                  if (!errcnt) {
938                      break;
939                  }
940                  (*errcnt)++;
941              } else if (offset + block_length > image_file_size) {
942                  error_report("VHDX BAT entry %" PRIu64 " end offset %" PRIu64
943                               " points after end of file (%" PRIi64 "). Image"
944                               " has probably been truncated.",
945                               i, offset + block_length - 1, image_file_size);
946                  ret = -EINVAL;
947                  if (!errcnt) {
948                      break;
949                  }
950                  (*errcnt)++;
951              }
952  
953              /*
954               * verify populated BAT field file offsets against
955               * region table and log entries
956               */
957              if (payblocks--) {
958                  /* payload bat entries */
959                  int ret2;
960                  ret2 = vhdx_region_check(s, offset, s->block_size);
961                  if (ret2 < 0) {
962                      ret = -EINVAL;
963                      if (!errcnt) {
964                          break;
965                      }
966                      (*errcnt)++;
967                  }
968              } else {
969                  payblocks = s->chunk_ratio;
970                  /*
971                   * Once differencing files are supported, verify sector bitmap
972                   * blocks here
973                   */
974              }
975          }
976      }
977  
978      return ret;
979  }
980  
vhdx_close(BlockDriverState * bs)981  static void vhdx_close(BlockDriverState *bs)
982  {
983      BDRVVHDXState *s = bs->opaque;
984      qemu_vfree(s->headers[0]);
985      s->headers[0] = NULL;
986      qemu_vfree(s->headers[1]);
987      s->headers[1] = NULL;
988      qemu_vfree(s->bat);
989      s->bat = NULL;
990      qemu_vfree(s->parent_entries);
991      s->parent_entries = NULL;
992      migrate_del_blocker(&s->migration_blocker);
993      qemu_vfree(s->log.hdr);
994      s->log.hdr = NULL;
995      vhdx_region_unregister_all(s);
996  }
997  
vhdx_open(BlockDriverState * bs,QDict * options,int flags,Error ** errp)998  static int vhdx_open(BlockDriverState *bs, QDict *options, int flags,
999                       Error **errp)
1000  {
1001      BDRVVHDXState *s = bs->opaque;
1002      int ret = 0;
1003      uint32_t i;
1004      uint64_t signature;
1005      Error *local_err = NULL;
1006  
1007      GLOBAL_STATE_CODE();
1008  
1009      ret = bdrv_open_file_child(NULL, options, "file", bs, errp);
1010      if (ret < 0) {
1011          return ret;
1012      }
1013  
1014      GRAPH_RDLOCK_GUARD_MAINLOOP();
1015  
1016      s->bat = NULL;
1017      s->first_visible_write = true;
1018  
1019      qemu_co_mutex_init(&s->lock);
1020      QLIST_INIT(&s->regions);
1021  
1022      /* validate the file signature */
1023      ret = bdrv_pread(bs->file, 0, sizeof(uint64_t), &signature, 0);
1024      if (ret < 0) {
1025          goto fail;
1026      }
1027      if (memcmp(&signature, "vhdxfile", 8)) {
1028          ret = -EINVAL;
1029          goto fail;
1030      }
1031  
1032      /* This is used for any header updates, for the file_write_guid.
1033       * The spec dictates that a new value should be used for the first
1034       * header update */
1035      vhdx_guid_generate(&s->session_guid);
1036  
1037      vhdx_parse_header(bs, s, &local_err);
1038      if (local_err != NULL) {
1039          error_propagate(errp, local_err);
1040          ret = -EINVAL;
1041          goto fail;
1042      }
1043  
1044      ret = vhdx_parse_log(bs, s, &s->log_replayed_on_open, errp);
1045      if (ret < 0) {
1046          goto fail;
1047      }
1048  
1049      ret = vhdx_open_region_tables(bs, s);
1050      if (ret < 0) {
1051          goto fail;
1052      }
1053  
1054      ret = vhdx_parse_metadata(bs, s);
1055      if (ret < 0) {
1056          goto fail;
1057      }
1058  
1059      s->block_size = s->params.block_size;
1060  
1061      /* the VHDX spec dictates that virtual_disk_size is always a multiple of
1062       * logical_sector_size */
1063      bs->total_sectors = s->virtual_disk_size >> s->logical_sector_size_bits;
1064  
1065      vhdx_calc_bat_entries(s);
1066  
1067      s->bat_offset = s->bat_rt.file_offset;
1068  
1069      if (s->bat_entries > s->bat_rt.length / sizeof(VHDXBatEntry)) {
1070          /* BAT allocation is not large enough for all entries */
1071          ret = -EINVAL;
1072          goto fail;
1073      }
1074  
1075      /* s->bat is freed in vhdx_close() */
1076      s->bat = qemu_try_blockalign(bs->file->bs, s->bat_rt.length);
1077      if (s->bat == NULL) {
1078          ret = -ENOMEM;
1079          goto fail;
1080      }
1081  
1082      ret = bdrv_pread(bs->file, s->bat_offset, s->bat_rt.length, s->bat, 0);
1083      if (ret < 0) {
1084          goto fail;
1085      }
1086  
1087      /* endian convert populated BAT field entries */
1088      for (i = 0; i < s->bat_entries; i++) {
1089          s->bat[i] = le64_to_cpu(s->bat[i]);
1090      }
1091  
1092      if (!(flags & BDRV_O_CHECK)) {
1093          ret = vhdx_check_bat_entries(bs, NULL);
1094          if (ret < 0) {
1095              goto fail;
1096          }
1097      }
1098  
1099      /* Disable migration when VHDX images are used */
1100      error_setg(&s->migration_blocker, "The vhdx format used by node '%s' "
1101                 "does not support live migration",
1102                 bdrv_get_device_or_node_name(bs));
1103      ret = migrate_add_blocker_normal(&s->migration_blocker, errp);
1104      if (ret < 0) {
1105          goto fail;
1106      }
1107  
1108      /* TODO: differencing files */
1109  
1110      return 0;
1111  fail:
1112      vhdx_close(bs);
1113      return ret;
1114  }
1115  
vhdx_reopen_prepare(BDRVReopenState * state,BlockReopenQueue * queue,Error ** errp)1116  static int vhdx_reopen_prepare(BDRVReopenState *state,
1117                                 BlockReopenQueue *queue, Error **errp)
1118  {
1119      return 0;
1120  }
1121  
1122  
1123  /*
1124   * Perform sector to block offset translations, to get various
1125   * sector and file offsets into the image.  See VHDXSectorInfo
1126   */
vhdx_block_translate(BDRVVHDXState * s,int64_t sector_num,int nb_sectors,VHDXSectorInfo * sinfo)1127  static void vhdx_block_translate(BDRVVHDXState *s, int64_t sector_num,
1128                                   int nb_sectors, VHDXSectorInfo *sinfo)
1129  {
1130      uint32_t block_offset;
1131  
1132      sinfo->bat_idx = sector_num >> s->sectors_per_block_bits;
1133      /* effectively a modulo - this gives us the offset into the block
1134       * (in sector sizes) for our sector number */
1135      block_offset = sector_num - (sinfo->bat_idx << s->sectors_per_block_bits);
1136      /* the chunk ratio gives us the interleaving of the sector
1137       * bitmaps, so we need to advance our page block index by the
1138       * sector bitmaps entry number */
1139      sinfo->bat_idx += sinfo->bat_idx >> s->chunk_ratio_bits;
1140  
1141      /* the number of sectors we can read/write in this cycle */
1142      sinfo->sectors_avail = s->sectors_per_block - block_offset;
1143  
1144      sinfo->bytes_left = sinfo->sectors_avail << s->logical_sector_size_bits;
1145  
1146      if (sinfo->sectors_avail > nb_sectors) {
1147          sinfo->sectors_avail = nb_sectors;
1148      }
1149  
1150      sinfo->bytes_avail = sinfo->sectors_avail << s->logical_sector_size_bits;
1151  
1152      sinfo->file_offset = s->bat[sinfo->bat_idx] & VHDX_BAT_FILE_OFF_MASK;
1153  
1154      sinfo->block_offset = block_offset << s->logical_sector_size_bits;
1155  
1156      /* The file offset must be past the header section, so must be > 0 */
1157      if (sinfo->file_offset == 0) {
1158          return;
1159      }
1160  
1161      /* block offset is the offset in vhdx logical sectors, in
1162       * the payload data block. Convert that to a byte offset
1163       * in the block, and add in the payload data block offset
1164       * in the file, in bytes, to get the final read address */
1165  
1166      sinfo->file_offset += sinfo->block_offset;
1167  }
1168  
1169  
1170  static int coroutine_fn
vhdx_co_get_info(BlockDriverState * bs,BlockDriverInfo * bdi)1171  vhdx_co_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
1172  {
1173      BDRVVHDXState *s = bs->opaque;
1174  
1175      bdi->cluster_size = s->block_size;
1176  
1177      return 0;
1178  }
1179  
1180  
1181  static int coroutine_fn GRAPH_RDLOCK
vhdx_co_readv(BlockDriverState * bs,int64_t sector_num,int nb_sectors,QEMUIOVector * qiov)1182  vhdx_co_readv(BlockDriverState *bs, int64_t sector_num, int nb_sectors,
1183                QEMUIOVector *qiov)
1184  {
1185      BDRVVHDXState *s = bs->opaque;
1186      int ret = 0;
1187      VHDXSectorInfo sinfo;
1188      uint64_t bytes_done = 0;
1189      QEMUIOVector hd_qiov;
1190  
1191      qemu_iovec_init(&hd_qiov, qiov->niov);
1192  
1193      qemu_co_mutex_lock(&s->lock);
1194  
1195      while (nb_sectors > 0) {
1196          /* We are a differencing file, so we need to inspect the sector bitmap
1197           * to see if we have the data or not */
1198          if (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) {
1199              /* not supported yet */
1200              ret = -ENOTSUP;
1201              goto exit;
1202          } else {
1203              vhdx_block_translate(s, sector_num, nb_sectors, &sinfo);
1204  
1205              qemu_iovec_reset(&hd_qiov);
1206              qemu_iovec_concat(&hd_qiov, qiov,  bytes_done, sinfo.bytes_avail);
1207  
1208              /* check the payload block state */
1209              switch (s->bat[sinfo.bat_idx] & VHDX_BAT_STATE_BIT_MASK) {
1210              case PAYLOAD_BLOCK_NOT_PRESENT: /* fall through */
1211              case PAYLOAD_BLOCK_UNDEFINED:
1212              case PAYLOAD_BLOCK_UNMAPPED:
1213              case PAYLOAD_BLOCK_UNMAPPED_v095:
1214              case PAYLOAD_BLOCK_ZERO:
1215                  /* return zero */
1216                  qemu_iovec_memset(&hd_qiov, 0, 0, sinfo.bytes_avail);
1217                  break;
1218              case PAYLOAD_BLOCK_FULLY_PRESENT:
1219                  qemu_co_mutex_unlock(&s->lock);
1220                  ret = bdrv_co_preadv(bs->file, sinfo.file_offset,
1221                                       sinfo.sectors_avail * BDRV_SECTOR_SIZE,
1222                                       &hd_qiov, 0);
1223                  qemu_co_mutex_lock(&s->lock);
1224                  if (ret < 0) {
1225                      goto exit;
1226                  }
1227                  break;
1228              case PAYLOAD_BLOCK_PARTIALLY_PRESENT:
1229                  /* we don't yet support difference files, fall through
1230                   * to error */
1231              default:
1232                  ret = -EIO;
1233                  goto exit;
1234                  break;
1235              }
1236              nb_sectors -= sinfo.sectors_avail;
1237              sector_num += sinfo.sectors_avail;
1238              bytes_done += sinfo.bytes_avail;
1239          }
1240      }
1241      ret = 0;
1242  exit:
1243      qemu_co_mutex_unlock(&s->lock);
1244      qemu_iovec_destroy(&hd_qiov);
1245      return ret;
1246  }
1247  
1248  /*
1249   * Allocate a new payload block at the end of the file.
1250   *
1251   * Allocation will happen at 1MB alignment inside the file.
1252   *
1253   * If @need_zero is set on entry but not cleared on return, then truncation
1254   * could not guarantee that the new portion reads as zero, and the caller
1255   * will take care of it instead.
1256   *
1257   * Returns the file offset start of the new payload block
1258   */
1259  static int coroutine_fn GRAPH_RDLOCK
vhdx_allocate_block(BlockDriverState * bs,BDRVVHDXState * s,uint64_t * new_offset,bool * need_zero)1260  vhdx_allocate_block(BlockDriverState *bs, BDRVVHDXState *s,
1261                      uint64_t *new_offset, bool *need_zero)
1262  {
1263      int64_t current_len;
1264  
1265      current_len = bdrv_co_getlength(bs->file->bs);
1266      if (current_len < 0) {
1267          return current_len;
1268      }
1269  
1270      *new_offset = current_len;
1271  
1272      /* per the spec, the address for a block is in units of 1MB */
1273      *new_offset = ROUND_UP(*new_offset, 1 * MiB);
1274      if (*new_offset > INT64_MAX) {
1275          return -EINVAL;
1276      }
1277  
1278      if (*need_zero) {
1279          int ret;
1280  
1281          ret = bdrv_co_truncate(bs->file, *new_offset + s->block_size, false,
1282                                 PREALLOC_MODE_OFF, BDRV_REQ_ZERO_WRITE, NULL);
1283          if (ret != -ENOTSUP) {
1284              *need_zero = false;
1285              return ret;
1286          }
1287      }
1288  
1289      return bdrv_co_truncate(bs->file, *new_offset + s->block_size, false,
1290                              PREALLOC_MODE_OFF, 0, NULL);
1291  }
1292  
1293  /*
1294   * Update the BAT table entry with the new file offset, and the new entry
1295   * state */
vhdx_update_bat_table_entry(BlockDriverState * bs,BDRVVHDXState * s,VHDXSectorInfo * sinfo,uint64_t * bat_entry_le,uint64_t * bat_offset,int state)1296  static void vhdx_update_bat_table_entry(BlockDriverState *bs, BDRVVHDXState *s,
1297                                         VHDXSectorInfo *sinfo,
1298                                         uint64_t *bat_entry_le,
1299                                         uint64_t *bat_offset, int state)
1300  {
1301      /* The BAT entry is a uint64, with 44 bits for the file offset in units of
1302       * 1MB, and 3 bits for the block state. */
1303      if ((state == PAYLOAD_BLOCK_ZERO)        ||
1304          (state == PAYLOAD_BLOCK_UNDEFINED)   ||
1305          (state == PAYLOAD_BLOCK_NOT_PRESENT) ||
1306          (state == PAYLOAD_BLOCK_UNMAPPED)) {
1307          s->bat[sinfo->bat_idx]  = 0;  /* For PAYLOAD_BLOCK_ZERO, the
1308                                           FileOffsetMB field is denoted as
1309                                           'reserved' in the v1.0 spec.  If it is
1310                                           non-zero, MS Hyper-V will fail to read
1311                                           the disk image */
1312      } else {
1313          s->bat[sinfo->bat_idx]  = sinfo->file_offset;
1314      }
1315  
1316      s->bat[sinfo->bat_idx] |= state & VHDX_BAT_STATE_BIT_MASK;
1317  
1318      *bat_entry_le = cpu_to_le64(s->bat[sinfo->bat_idx]);
1319      *bat_offset = s->bat_offset + sinfo->bat_idx * sizeof(VHDXBatEntry);
1320  
1321  }
1322  
1323  /* Per the spec, on the first write of guest-visible data to the file the
1324   * data write guid must be updated in the header */
vhdx_user_visible_write(BlockDriverState * bs,BDRVVHDXState * s)1325  int vhdx_user_visible_write(BlockDriverState *bs, BDRVVHDXState *s)
1326  {
1327      int ret = 0;
1328      if (s->first_visible_write) {
1329          s->first_visible_write = false;
1330          ret = vhdx_update_headers(bs, s, true, NULL);
1331      }
1332      return ret;
1333  }
1334  
1335  static int coroutine_fn GRAPH_RDLOCK
vhdx_co_writev(BlockDriverState * bs,int64_t sector_num,int nb_sectors,QEMUIOVector * qiov,int flags)1336  vhdx_co_writev(BlockDriverState *bs, int64_t sector_num, int nb_sectors,
1337                 QEMUIOVector *qiov, int flags)
1338  {
1339      int ret = -ENOTSUP;
1340      BDRVVHDXState *s = bs->opaque;
1341      VHDXSectorInfo sinfo;
1342      uint64_t bytes_done = 0;
1343      uint64_t bat_entry = 0;
1344      uint64_t bat_entry_offset = 0;
1345      QEMUIOVector hd_qiov;
1346      struct iovec iov1 = { 0 };
1347      struct iovec iov2 = { 0 };
1348      int sectors_to_write;
1349      int bat_state;
1350      uint64_t bat_prior_offset = 0;
1351      bool bat_update = false;
1352  
1353      qemu_iovec_init(&hd_qiov, qiov->niov);
1354  
1355      qemu_co_mutex_lock(&s->lock);
1356  
1357      ret = vhdx_user_visible_write(bs, s);
1358      if (ret < 0) {
1359          goto exit;
1360      }
1361  
1362      while (nb_sectors > 0) {
1363          bool use_zero_buffers = false;
1364          bat_update = false;
1365          if (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) {
1366              /* not supported yet */
1367              ret = -ENOTSUP;
1368              goto exit;
1369          } else {
1370              vhdx_block_translate(s, sector_num, nb_sectors, &sinfo);
1371              sectors_to_write = sinfo.sectors_avail;
1372  
1373              qemu_iovec_reset(&hd_qiov);
1374              /* check the payload block state */
1375              bat_state = s->bat[sinfo.bat_idx] & VHDX_BAT_STATE_BIT_MASK;
1376              switch (bat_state) {
1377              case PAYLOAD_BLOCK_ZERO:
1378                  /* in this case, we need to preserve zero writes for
1379                   * data that is not part of this write, so we must pad
1380                   * the rest of the buffer to zeroes */
1381                  use_zero_buffers = true;
1382                  /* fall through */
1383              case PAYLOAD_BLOCK_NOT_PRESENT: /* fall through */
1384              case PAYLOAD_BLOCK_UNMAPPED:
1385              case PAYLOAD_BLOCK_UNMAPPED_v095:
1386              case PAYLOAD_BLOCK_UNDEFINED:
1387                  bat_prior_offset = sinfo.file_offset;
1388                  ret = vhdx_allocate_block(bs, s, &sinfo.file_offset,
1389                                            &use_zero_buffers);
1390                  if (ret < 0) {
1391                      goto exit;
1392                  }
1393                  /*
1394                   * once we support differencing files, this may also be
1395                   * partially present
1396                   */
1397                  /* update block state to the newly specified state */
1398                  vhdx_update_bat_table_entry(bs, s, &sinfo, &bat_entry,
1399                                              &bat_entry_offset,
1400                                              PAYLOAD_BLOCK_FULLY_PRESENT);
1401                  bat_update = true;
1402                  /*
1403                   * Since we just allocated a block, file_offset is the
1404                   * beginning of the payload block. It needs to be the
1405                   * write address, which includes the offset into the
1406                   * block, unless the entire block needs to read as
1407                   * zeroes but truncation was not able to provide them,
1408                   * in which case we need to fill in the rest.
1409                   */
1410                  if (!use_zero_buffers) {
1411                      sinfo.file_offset += sinfo.block_offset;
1412                  } else {
1413                      /* zero fill the front, if any */
1414                      if (sinfo.block_offset) {
1415                          iov1.iov_len = sinfo.block_offset;
1416                          iov1.iov_base = qemu_blockalign(bs, iov1.iov_len);
1417                          memset(iov1.iov_base, 0, iov1.iov_len);
1418                          qemu_iovec_concat_iov(&hd_qiov, &iov1, 1, 0,
1419                                                iov1.iov_len);
1420                          sectors_to_write += iov1.iov_len >> BDRV_SECTOR_BITS;
1421                      }
1422  
1423                      /* our actual data */
1424                      qemu_iovec_concat(&hd_qiov, qiov, bytes_done,
1425                                        sinfo.bytes_avail);
1426  
1427                      /* zero fill the back, if any */
1428                      if ((sinfo.bytes_avail - sinfo.block_offset) <
1429                           s->block_size) {
1430                          iov2.iov_len = s->block_size -
1431                                        (sinfo.bytes_avail + sinfo.block_offset);
1432                          iov2.iov_base = qemu_blockalign(bs, iov2.iov_len);
1433                          memset(iov2.iov_base, 0, iov2.iov_len);
1434                          qemu_iovec_concat_iov(&hd_qiov, &iov2, 1, 0,
1435                                                iov2.iov_len);
1436                          sectors_to_write += iov2.iov_len >> BDRV_SECTOR_BITS;
1437                      }
1438                  }
1439  
1440                  /* fall through */
1441              case PAYLOAD_BLOCK_FULLY_PRESENT:
1442                  /* if the file offset address is in the header zone,
1443                   * there is a problem */
1444                  if (sinfo.file_offset < (1 * MiB)) {
1445                      ret = -EFAULT;
1446                      goto error_bat_restore;
1447                  }
1448  
1449                  if (!use_zero_buffers) {
1450                      qemu_iovec_concat(&hd_qiov, qiov,  bytes_done,
1451                                        sinfo.bytes_avail);
1452                  }
1453                  /* block exists, so we can just overwrite it */
1454                  qemu_co_mutex_unlock(&s->lock);
1455                  ret = bdrv_co_pwritev(bs->file, sinfo.file_offset,
1456                                        sectors_to_write * BDRV_SECTOR_SIZE,
1457                                        &hd_qiov, 0);
1458                  qemu_co_mutex_lock(&s->lock);
1459                  if (ret < 0) {
1460                      goto error_bat_restore;
1461                  }
1462                  break;
1463              case PAYLOAD_BLOCK_PARTIALLY_PRESENT:
1464                  /* we don't yet support difference files, fall through
1465                   * to error */
1466              default:
1467                  ret = -EIO;
1468                  goto exit;
1469                  break;
1470              }
1471  
1472              if (bat_update) {
1473                  /* this will update the BAT entry into the log journal, and
1474                   * then flush the log journal out to disk */
1475                  ret =  vhdx_log_write_and_flush(bs, s, &bat_entry,
1476                                                  sizeof(VHDXBatEntry),
1477                                                  bat_entry_offset);
1478                  if (ret < 0) {
1479                      goto exit;
1480                  }
1481              }
1482  
1483              nb_sectors -= sinfo.sectors_avail;
1484              sector_num += sinfo.sectors_avail;
1485              bytes_done += sinfo.bytes_avail;
1486  
1487          }
1488      }
1489  
1490      goto exit;
1491  
1492  error_bat_restore:
1493      if (bat_update) {
1494          /* keep metadata in sync, and restore the bat entry state
1495           * if error. */
1496          sinfo.file_offset = bat_prior_offset;
1497          vhdx_update_bat_table_entry(bs, s, &sinfo, &bat_entry,
1498                                      &bat_entry_offset, bat_state);
1499      }
1500  exit:
1501      qemu_vfree(iov1.iov_base);
1502      qemu_vfree(iov2.iov_base);
1503      qemu_co_mutex_unlock(&s->lock);
1504      qemu_iovec_destroy(&hd_qiov);
1505      return ret;
1506  }
1507  
1508  
1509  
1510  /*
1511   * Create VHDX Headers
1512   *
1513   * There are 2 headers, and the highest sequence number will represent
1514   * the active header
1515   */
1516  static int coroutine_fn GRAPH_UNLOCKED
vhdx_create_new_headers(BlockBackend * blk,uint64_t image_size,uint32_t log_size)1517  vhdx_create_new_headers(BlockBackend *blk, uint64_t image_size,
1518                          uint32_t log_size)
1519  {
1520      BlockDriverState *bs = blk_bs(blk);
1521      BdrvChild *child;
1522      int ret = 0;
1523      VHDXHeader *hdr = NULL;
1524  
1525      GRAPH_RDLOCK_GUARD();
1526  
1527      hdr = g_new0(VHDXHeader, 1);
1528  
1529      hdr->signature       = VHDX_HEADER_SIGNATURE;
1530      hdr->sequence_number = g_random_int();
1531      hdr->log_version     = 0;
1532      hdr->version         = 1;
1533      hdr->log_length      = log_size;
1534      hdr->log_offset      = VHDX_HEADER_SECTION_END;
1535      vhdx_guid_generate(&hdr->file_write_guid);
1536      vhdx_guid_generate(&hdr->data_write_guid);
1537  
1538      /* XXX Ugly way to get blk->root, but that's a feature, not a bug. This
1539       * hack makes it obvious that vhdx_write_header() bypasses the BlockBackend
1540       * here, which it really shouldn't be doing. */
1541      child = QLIST_FIRST(&bs->parents);
1542      assert(!QLIST_NEXT(child, next_parent));
1543  
1544      ret = vhdx_write_header(child, hdr, VHDX_HEADER1_OFFSET, false);
1545      if (ret < 0) {
1546          goto exit;
1547      }
1548      hdr->sequence_number++;
1549      ret = vhdx_write_header(child, hdr, VHDX_HEADER2_OFFSET, false);
1550      if (ret < 0) {
1551          goto exit;
1552      }
1553  
1554  exit:
1555      g_free(hdr);
1556      return ret;
1557  }
1558  
1559  #define VHDX_METADATA_ENTRY_BUFFER_SIZE \
1560                                      (sizeof(VHDXFileParameters)               +\
1561                                       sizeof(VHDXVirtualDiskSize)              +\
1562                                       sizeof(VHDXPage83Data)                   +\
1563                                       sizeof(VHDXVirtualDiskLogicalSectorSize) +\
1564                                       sizeof(VHDXVirtualDiskPhysicalSectorSize))
1565  
1566  /*
1567   * Create the Metadata entries.
1568   *
1569   * For more details on the entries, see section 3.5 (pg 29) in the
1570   * VHDX 1.00 specification.
1571   *
1572   * We support 5 metadata entries (all required by spec):
1573   *          File Parameters,
1574   *          Virtual Disk Size,
1575   *          Page 83 Data,
1576   *          Logical Sector Size,
1577   *          Physical Sector Size
1578   *
1579   * The first 64KB of the Metadata section is reserved for the metadata
1580   * header and entries; beyond that, the metadata items themselves reside.
1581   */
1582  static int coroutine_fn
vhdx_create_new_metadata(BlockBackend * blk,uint64_t image_size,uint32_t block_size,uint32_t sector_size,uint64_t metadata_offset,VHDXImageType type)1583  vhdx_create_new_metadata(BlockBackend *blk, uint64_t image_size,
1584                           uint32_t block_size, uint32_t sector_size,
1585                           uint64_t metadata_offset, VHDXImageType type)
1586  {
1587      int ret = 0;
1588      uint32_t offset = 0;
1589      void *buffer = NULL;
1590      void *entry_buffer;
1591      VHDXMetadataTableHeader *md_table;
1592      VHDXMetadataTableEntry  *md_table_entry;
1593  
1594      /* Metadata entries */
1595      VHDXFileParameters     *mt_file_params;
1596      VHDXVirtualDiskSize    *mt_virtual_size;
1597      VHDXPage83Data         *mt_page83;
1598      VHDXVirtualDiskLogicalSectorSize  *mt_log_sector_size;
1599      VHDXVirtualDiskPhysicalSectorSize *mt_phys_sector_size;
1600  
1601      entry_buffer = g_malloc0(VHDX_METADATA_ENTRY_BUFFER_SIZE);
1602  
1603      mt_file_params = entry_buffer;
1604      offset += sizeof(VHDXFileParameters);
1605      mt_virtual_size = entry_buffer + offset;
1606      offset += sizeof(VHDXVirtualDiskSize);
1607      mt_page83 = entry_buffer + offset;
1608      offset += sizeof(VHDXPage83Data);
1609      mt_log_sector_size = entry_buffer + offset;
1610      offset += sizeof(VHDXVirtualDiskLogicalSectorSize);
1611      mt_phys_sector_size = entry_buffer + offset;
1612  
1613      mt_file_params->block_size = cpu_to_le32(block_size);
1614      if (type == VHDX_TYPE_FIXED) {
1615          mt_file_params->data_bits |= VHDX_PARAMS_LEAVE_BLOCKS_ALLOCED;
1616          mt_file_params->data_bits = cpu_to_le32(mt_file_params->data_bits);
1617      }
1618  
1619      vhdx_guid_generate(&mt_page83->page_83_data);
1620      cpu_to_leguids(&mt_page83->page_83_data);
1621      mt_virtual_size->virtual_disk_size        = cpu_to_le64(image_size);
1622      mt_log_sector_size->logical_sector_size   = cpu_to_le32(sector_size);
1623      mt_phys_sector_size->physical_sector_size = cpu_to_le32(sector_size);
1624  
1625      buffer = g_malloc0(VHDX_HEADER_BLOCK_SIZE);
1626      md_table = buffer;
1627  
1628      md_table->signature   = VHDX_METADATA_SIGNATURE;
1629      md_table->entry_count = 5;
1630      vhdx_metadata_header_le_export(md_table);
1631  
1632  
1633      /* This will reference beyond the reserved table portion */
1634      offset = 64 * KiB;
1635  
1636      md_table_entry = buffer + sizeof(VHDXMetadataTableHeader);
1637  
1638      md_table_entry[0].item_id = file_param_guid;
1639      md_table_entry[0].offset  = offset;
1640      md_table_entry[0].length  = sizeof(VHDXFileParameters);
1641      md_table_entry[0].data_bits |= VHDX_META_FLAGS_IS_REQUIRED;
1642      offset += md_table_entry[0].length;
1643      vhdx_metadata_entry_le_export(&md_table_entry[0]);
1644  
1645      md_table_entry[1].item_id = virtual_size_guid;
1646      md_table_entry[1].offset  = offset;
1647      md_table_entry[1].length  = sizeof(VHDXVirtualDiskSize);
1648      md_table_entry[1].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
1649                                     VHDX_META_FLAGS_IS_VIRTUAL_DISK;
1650      offset += md_table_entry[1].length;
1651      vhdx_metadata_entry_le_export(&md_table_entry[1]);
1652  
1653      md_table_entry[2].item_id = page83_guid;
1654      md_table_entry[2].offset  = offset;
1655      md_table_entry[2].length  = sizeof(VHDXPage83Data);
1656      md_table_entry[2].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
1657                                     VHDX_META_FLAGS_IS_VIRTUAL_DISK;
1658      offset += md_table_entry[2].length;
1659      vhdx_metadata_entry_le_export(&md_table_entry[2]);
1660  
1661      md_table_entry[3].item_id = logical_sector_guid;
1662      md_table_entry[3].offset  = offset;
1663      md_table_entry[3].length  = sizeof(VHDXVirtualDiskLogicalSectorSize);
1664      md_table_entry[3].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
1665                                     VHDX_META_FLAGS_IS_VIRTUAL_DISK;
1666      offset += md_table_entry[3].length;
1667      vhdx_metadata_entry_le_export(&md_table_entry[3]);
1668  
1669      md_table_entry[4].item_id = phys_sector_guid;
1670      md_table_entry[4].offset  = offset;
1671      md_table_entry[4].length  = sizeof(VHDXVirtualDiskPhysicalSectorSize);
1672      md_table_entry[4].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
1673                                     VHDX_META_FLAGS_IS_VIRTUAL_DISK;
1674      vhdx_metadata_entry_le_export(&md_table_entry[4]);
1675  
1676      ret = blk_co_pwrite(blk, metadata_offset, VHDX_HEADER_BLOCK_SIZE, buffer, 0);
1677      if (ret < 0) {
1678          goto exit;
1679      }
1680  
1681      ret = blk_co_pwrite(blk, metadata_offset + (64 * KiB),
1682                          VHDX_METADATA_ENTRY_BUFFER_SIZE, entry_buffer, 0);
1683      if (ret < 0) {
1684          goto exit;
1685      }
1686  
1687  
1688  exit:
1689      g_free(buffer);
1690      g_free(entry_buffer);
1691      return ret;
1692  }
1693  
1694  /* This create the actual BAT itself.  We currently only support
1695   * 'Dynamic' and 'Fixed' image types.
1696   *
1697   *  Dynamic images: default state of the BAT is all zeroes.
1698   *
1699   *  Fixed images: default state of the BAT is fully populated, with
1700   *                file offsets and state PAYLOAD_BLOCK_FULLY_PRESENT.
1701   */
1702  static int coroutine_fn GRAPH_UNLOCKED
vhdx_create_bat(BlockBackend * blk,BDRVVHDXState * s,uint64_t image_size,VHDXImageType type,bool use_zero_blocks,uint64_t file_offset,uint32_t length,Error ** errp)1703  vhdx_create_bat(BlockBackend *blk, BDRVVHDXState *s,
1704                  uint64_t image_size, VHDXImageType type,
1705                  bool use_zero_blocks, uint64_t file_offset,
1706                  uint32_t length, Error **errp)
1707  {
1708      int ret = 0;
1709      uint64_t data_file_offset;
1710      uint64_t total_sectors = 0;
1711      uint64_t sector_num = 0;
1712      uint64_t unused;
1713      int block_state;
1714      VHDXSectorInfo sinfo;
1715      bool has_zero_init;
1716  
1717      assert(s->bat == NULL);
1718  
1719      /* this gives a data start after BAT/bitmap entries, and well
1720       * past any metadata entries (with a 4 MB buffer for future
1721       * expansion */
1722      data_file_offset = file_offset + length + 5 * MiB;
1723      total_sectors = image_size >> s->logical_sector_size_bits;
1724  
1725      if (type == VHDX_TYPE_DYNAMIC) {
1726          /* All zeroes, so we can just extend the file - the end of the BAT
1727           * is the furthest thing we have written yet */
1728          ret = blk_co_truncate(blk, data_file_offset, false, PREALLOC_MODE_OFF,
1729                                0, errp);
1730          if (ret < 0) {
1731              goto exit;
1732          }
1733      } else if (type == VHDX_TYPE_FIXED) {
1734          ret = blk_co_truncate(blk, data_file_offset + image_size, false,
1735                                PREALLOC_MODE_OFF, 0, errp);
1736          if (ret < 0) {
1737              goto exit;
1738          }
1739      } else {
1740          error_setg(errp, "Unsupported image type");
1741          ret = -ENOTSUP;
1742          goto exit;
1743      }
1744  
1745      bdrv_graph_co_rdlock();
1746      has_zero_init = bdrv_has_zero_init(blk_bs(blk));
1747      bdrv_graph_co_rdunlock();
1748  
1749      if (type == VHDX_TYPE_FIXED ||
1750                  use_zero_blocks ||
1751                  has_zero_init == 0) {
1752          /* for a fixed file, the default BAT entry is not zero */
1753          s->bat = g_try_malloc0(length);
1754          if (length && s->bat == NULL) {
1755              error_setg(errp, "Failed to allocate memory for the BAT");
1756              ret = -ENOMEM;
1757              goto exit;
1758          }
1759          block_state = type == VHDX_TYPE_FIXED ? PAYLOAD_BLOCK_FULLY_PRESENT :
1760                                                  PAYLOAD_BLOCK_NOT_PRESENT;
1761          block_state = use_zero_blocks ? PAYLOAD_BLOCK_ZERO : block_state;
1762          /* fill the BAT by emulating sector writes of sectors_per_block size */
1763          while (sector_num < total_sectors) {
1764              vhdx_block_translate(s, sector_num, s->sectors_per_block, &sinfo);
1765              sinfo.file_offset = data_file_offset +
1766                                  (sector_num << s->logical_sector_size_bits);
1767              sinfo.file_offset = ROUND_UP(sinfo.file_offset, MiB);
1768              vhdx_update_bat_table_entry(blk_bs(blk), s, &sinfo, &unused, &unused,
1769                                          block_state);
1770              s->bat[sinfo.bat_idx] = cpu_to_le64(s->bat[sinfo.bat_idx]);
1771              sector_num += s->sectors_per_block;
1772          }
1773          ret = blk_co_pwrite(blk, file_offset, length, s->bat, 0);
1774          if (ret < 0) {
1775              error_setg_errno(errp, -ret, "Failed to write the BAT");
1776              goto exit;
1777          }
1778      }
1779  
1780  
1781  
1782  exit:
1783      g_free(s->bat);
1784      return ret;
1785  }
1786  
1787  /* Creates the region table header, and region table entries.
1788   * There are 2 supported region table entries: BAT, and Metadata/
1789   *
1790   * As the calculations for the BAT region table are also needed
1791   * to create the BAT itself, we will also cause the BAT to be
1792   * created.
1793   */
1794  static int coroutine_fn GRAPH_UNLOCKED
vhdx_create_new_region_table(BlockBackend * blk,uint64_t image_size,uint32_t block_size,uint32_t sector_size,uint32_t log_size,bool use_zero_blocks,VHDXImageType type,uint64_t * metadata_offset,Error ** errp)1795  vhdx_create_new_region_table(BlockBackend *blk, uint64_t image_size,
1796                               uint32_t block_size, uint32_t sector_size,
1797                               uint32_t log_size, bool use_zero_blocks,
1798                               VHDXImageType type, uint64_t *metadata_offset,
1799                               Error **errp)
1800  {
1801      int ret = 0;
1802      uint32_t offset = 0;
1803      void *buffer = NULL;
1804      uint64_t bat_file_offset;
1805      uint32_t bat_length;
1806      BDRVVHDXState *s = NULL;
1807      VHDXRegionTableHeader *region_table;
1808      VHDXRegionTableEntry *rt_bat;
1809      VHDXRegionTableEntry *rt_metadata;
1810  
1811      assert(metadata_offset != NULL);
1812  
1813      /* Populate enough of the BDRVVHDXState to be able to use the
1814       * pre-existing BAT calculation, translation, and update functions */
1815      s = g_new0(BDRVVHDXState, 1);
1816  
1817      s->chunk_ratio = (VHDX_MAX_SECTORS_PER_BLOCK) *
1818                       (uint64_t) sector_size / (uint64_t) block_size;
1819  
1820      s->sectors_per_block = block_size / sector_size;
1821      s->virtual_disk_size = image_size;
1822      s->block_size = block_size;
1823      s->logical_sector_size = sector_size;
1824  
1825      vhdx_set_shift_bits(s);
1826  
1827      vhdx_calc_bat_entries(s);
1828  
1829      /* At this point the VHDX state is populated enough for creation */
1830  
1831      /* a single buffer is used so we can calculate the checksum over the
1832       * entire 64KB block */
1833      buffer = g_malloc0(VHDX_HEADER_BLOCK_SIZE);
1834      region_table = buffer;
1835      offset += sizeof(VHDXRegionTableHeader);
1836      rt_bat = buffer + offset;
1837      offset += sizeof(VHDXRegionTableEntry);
1838      rt_metadata  = buffer + offset;
1839  
1840      region_table->signature = VHDX_REGION_SIGNATURE;
1841      region_table->entry_count = 2;   /* BAT and Metadata */
1842  
1843      rt_bat->guid        = bat_guid;
1844      rt_bat->length      = ROUND_UP(s->bat_entries * sizeof(VHDXBatEntry), MiB);
1845      rt_bat->file_offset = ROUND_UP(VHDX_HEADER_SECTION_END + log_size, MiB);
1846      s->bat_offset = rt_bat->file_offset;
1847  
1848      rt_metadata->guid        = metadata_guid;
1849      rt_metadata->file_offset = ROUND_UP(rt_bat->file_offset + rt_bat->length,
1850                                          MiB);
1851      rt_metadata->length      = 1 * MiB; /* min size, and more than enough */
1852      *metadata_offset = rt_metadata->file_offset;
1853  
1854      bat_file_offset = rt_bat->file_offset;
1855      bat_length = rt_bat->length;
1856  
1857      vhdx_region_header_le_export(region_table);
1858      vhdx_region_entry_le_export(rt_bat);
1859      vhdx_region_entry_le_export(rt_metadata);
1860  
1861      vhdx_update_checksum(buffer, VHDX_HEADER_BLOCK_SIZE,
1862                           offsetof(VHDXRegionTableHeader, checksum));
1863  
1864  
1865      /* The region table gives us the data we need to create the BAT,
1866       * so do that now */
1867      ret = vhdx_create_bat(blk, s, image_size, type, use_zero_blocks,
1868                            bat_file_offset, bat_length, errp);
1869      if (ret < 0) {
1870          goto exit;
1871      }
1872  
1873      /* Now write out the region headers to disk */
1874      ret = blk_co_pwrite(blk, VHDX_REGION_TABLE_OFFSET, VHDX_HEADER_BLOCK_SIZE,
1875                          buffer, 0);
1876      if (ret < 0) {
1877          error_setg_errno(errp, -ret, "Failed to write first region table");
1878          goto exit;
1879      }
1880  
1881      ret = blk_co_pwrite(blk, VHDX_REGION_TABLE2_OFFSET, VHDX_HEADER_BLOCK_SIZE,
1882                          buffer, 0);
1883      if (ret < 0) {
1884          error_setg_errno(errp, -ret, "Failed to write second region table");
1885          goto exit;
1886      }
1887  
1888  exit:
1889      g_free(s);
1890      g_free(buffer);
1891      return ret;
1892  }
1893  
1894  /* We need to create the following elements:
1895   *
1896   *    .-----------------------------------------------------------------.
1897   *    |   (A)    |   (B)    |    (C)    |     (D)       |     (E)       |
1898   *    |  File ID |  Header1 |  Header 2 |  Region Tbl 1 |  Region Tbl 2 |
1899   *    |          |          |           |               |               |
1900   *    .-----------------------------------------------------------------.
1901   *    0         64KB      128KB       192KB           256KB           320KB
1902   *
1903   *
1904   *    .---- ~ ----------- ~ ------------ ~ ---------------- ~ -----------.
1905   *    |     (F)     |     (G)       |    (H)    |                        |
1906   *    | Journal Log |  BAT / Bitmap |  Metadata |  .... data ......      |
1907   *    |             |               |           |                        |
1908   *    .---- ~ ----------- ~ ------------ ~ ---------------- ~ -----------.
1909   *   1MB
1910   */
1911  static int coroutine_fn GRAPH_UNLOCKED
vhdx_co_create(BlockdevCreateOptions * opts,Error ** errp)1912  vhdx_co_create(BlockdevCreateOptions *opts, Error **errp)
1913  {
1914      BlockdevCreateOptionsVhdx *vhdx_opts;
1915      BlockBackend *blk = NULL;
1916      BlockDriverState *bs = NULL;
1917  
1918      int ret = 0;
1919      uint64_t image_size;
1920      uint32_t log_size;
1921      uint32_t block_size;
1922      uint64_t signature;
1923      uint64_t metadata_offset;
1924      bool use_zero_blocks = false;
1925  
1926      gunichar2 *creator = NULL;
1927      glong creator_items;
1928      VHDXImageType image_type;
1929  
1930      assert(opts->driver == BLOCKDEV_DRIVER_VHDX);
1931      vhdx_opts = &opts->u.vhdx;
1932  
1933      /* Validate options and set default values */
1934      image_size = vhdx_opts->size;
1935      if (image_size > VHDX_MAX_IMAGE_SIZE) {
1936          error_setg(errp, "Image size too large; max of 64TB");
1937          return -EINVAL;
1938      }
1939  
1940      if (!vhdx_opts->has_log_size) {
1941          log_size = DEFAULT_LOG_SIZE;
1942      } else {
1943          if (vhdx_opts->log_size > UINT32_MAX) {
1944              error_setg(errp, "Log size must be smaller than 4 GB");
1945              return -EINVAL;
1946          }
1947          log_size = vhdx_opts->log_size;
1948      }
1949      if (log_size < MiB || (log_size % MiB) != 0) {
1950          error_setg(errp, "Log size must be a multiple of 1 MB");
1951          return -EINVAL;
1952      }
1953  
1954      if (!vhdx_opts->has_block_state_zero) {
1955          use_zero_blocks = true;
1956      } else {
1957          use_zero_blocks = vhdx_opts->block_state_zero;
1958      }
1959  
1960      if (!vhdx_opts->has_subformat) {
1961          vhdx_opts->subformat = BLOCKDEV_VHDX_SUBFORMAT_DYNAMIC;
1962      }
1963  
1964      switch (vhdx_opts->subformat) {
1965      case BLOCKDEV_VHDX_SUBFORMAT_DYNAMIC:
1966          image_type = VHDX_TYPE_DYNAMIC;
1967          break;
1968      case BLOCKDEV_VHDX_SUBFORMAT_FIXED:
1969          image_type = VHDX_TYPE_FIXED;
1970          break;
1971      default:
1972          g_assert_not_reached();
1973      }
1974  
1975      /* These are pretty arbitrary, and mainly designed to keep the BAT
1976       * size reasonable to load into RAM */
1977      if (vhdx_opts->has_block_size) {
1978          block_size = vhdx_opts->block_size;
1979      } else {
1980          if (image_size > 32 * TiB) {
1981              block_size = 64 * MiB;
1982          } else if (image_size > (uint64_t) 100 * GiB) {
1983              block_size = 32 * MiB;
1984          } else if (image_size > 1 * GiB) {
1985              block_size = 16 * MiB;
1986          } else {
1987              block_size = 8 * MiB;
1988          }
1989      }
1990  
1991      if (block_size < MiB || (block_size % MiB) != 0) {
1992          error_setg(errp, "Block size must be a multiple of 1 MB");
1993          return -EINVAL;
1994      }
1995      if (!is_power_of_2(block_size)) {
1996          error_setg(errp, "Block size must be a power of two");
1997          return -EINVAL;
1998      }
1999      if (block_size > VHDX_BLOCK_SIZE_MAX) {
2000          error_setg(errp, "Block size must not exceed %" PRId64,
2001                     VHDX_BLOCK_SIZE_MAX);
2002          return -EINVAL;
2003      }
2004  
2005      /* Create BlockBackend to write to the image */
2006      bs = bdrv_co_open_blockdev_ref(vhdx_opts->file, errp);
2007      if (bs == NULL) {
2008          return -EIO;
2009      }
2010  
2011      blk = blk_co_new_with_bs(bs, BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL,
2012                               errp);
2013      if (!blk) {
2014          ret = -EPERM;
2015          goto delete_and_exit;
2016      }
2017      blk_set_allow_write_beyond_eof(blk, true);
2018  
2019      /* Create (A) */
2020  
2021      /* The creator field is optional, but may be useful for
2022       * debugging / diagnostics */
2023      creator = g_utf8_to_utf16("QEMU v" QEMU_VERSION, -1, NULL,
2024                                &creator_items, NULL);
2025      signature = cpu_to_le64(VHDX_FILE_SIGNATURE);
2026      ret = blk_co_pwrite(blk, VHDX_FILE_ID_OFFSET, sizeof(signature), &signature,
2027                          0);
2028      if (ret < 0) {
2029          error_setg_errno(errp, -ret, "Failed to write file signature");
2030          goto delete_and_exit;
2031      }
2032      if (creator) {
2033          ret = blk_co_pwrite(blk, VHDX_FILE_ID_OFFSET + sizeof(signature),
2034                              creator_items * sizeof(gunichar2), creator, 0);
2035          if (ret < 0) {
2036              error_setg_errno(errp, -ret, "Failed to write creator field");
2037              goto delete_and_exit;
2038          }
2039      }
2040  
2041  
2042      /* Creates (B),(C) */
2043      ret = vhdx_create_new_headers(blk, image_size, log_size);
2044      if (ret < 0) {
2045          error_setg_errno(errp, -ret, "Failed to write image headers");
2046          goto delete_and_exit;
2047      }
2048  
2049      /* Creates (D),(E),(G) explicitly. (F) created as by-product */
2050      ret = vhdx_create_new_region_table(blk, image_size, block_size, 512,
2051                                         log_size, use_zero_blocks, image_type,
2052                                         &metadata_offset, errp);
2053      if (ret < 0) {
2054          goto delete_and_exit;
2055      }
2056  
2057      /* Creates (H) */
2058      ret = vhdx_create_new_metadata(blk, image_size, block_size, 512,
2059                                     metadata_offset, image_type);
2060      if (ret < 0) {
2061          error_setg_errno(errp, -ret, "Failed to initialize metadata");
2062          goto delete_and_exit;
2063      }
2064  
2065      ret = 0;
2066  delete_and_exit:
2067      blk_co_unref(blk);
2068      bdrv_co_unref(bs);
2069      g_free(creator);
2070      return ret;
2071  }
2072  
2073  static int coroutine_fn GRAPH_UNLOCKED
vhdx_co_create_opts(BlockDriver * drv,const char * filename,QemuOpts * opts,Error ** errp)2074  vhdx_co_create_opts(BlockDriver *drv, const char *filename,
2075                      QemuOpts *opts, Error **errp)
2076  {
2077      BlockdevCreateOptions *create_options = NULL;
2078      QDict *qdict;
2079      Visitor *v;
2080      BlockDriverState *bs = NULL;
2081      int ret;
2082  
2083      static const QDictRenames opt_renames[] = {
2084          { VHDX_BLOCK_OPT_LOG_SIZE,      "log-size" },
2085          { VHDX_BLOCK_OPT_BLOCK_SIZE,    "block-size" },
2086          { VHDX_BLOCK_OPT_ZERO,          "block-state-zero" },
2087          { NULL, NULL },
2088      };
2089  
2090      /* Parse options and convert legacy syntax */
2091      qdict = qemu_opts_to_qdict_filtered(opts, NULL, &vhdx_create_opts, true);
2092  
2093      if (!qdict_rename_keys(qdict, opt_renames, errp)) {
2094          ret = -EINVAL;
2095          goto fail;
2096      }
2097  
2098      /* Create and open the file (protocol layer) */
2099      ret = bdrv_co_create_file(filename, opts, errp);
2100      if (ret < 0) {
2101          goto fail;
2102      }
2103  
2104      bs = bdrv_co_open(filename, NULL, NULL,
2105                        BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp);
2106      if (bs == NULL) {
2107          ret = -EIO;
2108          goto fail;
2109      }
2110  
2111      /* Now get the QAPI type BlockdevCreateOptions */
2112      qdict_put_str(qdict, "driver", "vhdx");
2113      qdict_put_str(qdict, "file", bs->node_name);
2114  
2115      v = qobject_input_visitor_new_flat_confused(qdict, errp);
2116      if (!v) {
2117          ret = -EINVAL;
2118          goto fail;
2119      }
2120  
2121      visit_type_BlockdevCreateOptions(v, NULL, &create_options, errp);
2122      visit_free(v);
2123      if (!create_options) {
2124          ret = -EINVAL;
2125          goto fail;
2126      }
2127  
2128      /* Silently round up sizes:
2129       * The image size is rounded to 512 bytes. Make the block and log size
2130       * close to what was specified, but must be at least 1MB, and a multiple of
2131       * 1 MB. Also respect VHDX_BLOCK_SIZE_MAX for block sizes. block_size = 0
2132       * means auto, which is represented by a missing key in QAPI. */
2133      assert(create_options->driver == BLOCKDEV_DRIVER_VHDX);
2134      create_options->u.vhdx.size =
2135          ROUND_UP(create_options->u.vhdx.size, BDRV_SECTOR_SIZE);
2136  
2137      if (create_options->u.vhdx.has_log_size) {
2138          create_options->u.vhdx.log_size =
2139              ROUND_UP(create_options->u.vhdx.log_size, MiB);
2140      }
2141      if (create_options->u.vhdx.has_block_size) {
2142          create_options->u.vhdx.block_size =
2143              ROUND_UP(create_options->u.vhdx.block_size, MiB);
2144  
2145          if (create_options->u.vhdx.block_size == 0) {
2146              create_options->u.vhdx.has_block_size = false;
2147          }
2148          if (create_options->u.vhdx.block_size > VHDX_BLOCK_SIZE_MAX) {
2149              create_options->u.vhdx.block_size = VHDX_BLOCK_SIZE_MAX;
2150          }
2151      }
2152  
2153      /* Create the vhdx image (format layer) */
2154      ret = vhdx_co_create(create_options, errp);
2155  
2156  fail:
2157      qobject_unref(qdict);
2158      bdrv_co_unref(bs);
2159      qapi_free_BlockdevCreateOptions(create_options);
2160      return ret;
2161  }
2162  
2163  /* If opened r/w, the VHDX driver will automatically replay the log,
2164   * if one is present, inside the vhdx_open() call.
2165   *
2166   * If qemu-img check -r all is called, the image is automatically opened
2167   * r/w and any log has already been replayed, so there is nothing (currently)
2168   * for us to do here
2169   */
2170  static int coroutine_fn GRAPH_RDLOCK
vhdx_co_check(BlockDriverState * bs,BdrvCheckResult * result,BdrvCheckMode fix)2171  vhdx_co_check(BlockDriverState *bs, BdrvCheckResult *result,
2172                BdrvCheckMode fix)
2173  {
2174      BDRVVHDXState *s = bs->opaque;
2175  
2176      if (s->log_replayed_on_open) {
2177          result->corruptions_fixed++;
2178      }
2179  
2180      vhdx_check_bat_entries(bs, &result->corruptions);
2181  
2182      return 0;
2183  }
2184  
vhdx_has_zero_init(BlockDriverState * bs)2185  static int GRAPH_RDLOCK vhdx_has_zero_init(BlockDriverState *bs)
2186  {
2187      BDRVVHDXState *s = bs->opaque;
2188      int state;
2189  
2190      /*
2191       * Check the subformat: Fixed images have all BAT entries present,
2192       * dynamic images have none (right after creation).  It is
2193       * therefore enough to check the first BAT entry.
2194       */
2195      if (!s->bat_entries) {
2196          return 1;
2197      }
2198  
2199      state = s->bat[0] & VHDX_BAT_STATE_BIT_MASK;
2200      if (state == PAYLOAD_BLOCK_FULLY_PRESENT) {
2201          /* Fixed subformat */
2202          return bdrv_has_zero_init(bs->file->bs);
2203      }
2204  
2205      /* Dynamic subformat */
2206      return 1;
2207  }
2208  
2209  static QemuOptsList vhdx_create_opts = {
2210      .name = "vhdx-create-opts",
2211      .head = QTAILQ_HEAD_INITIALIZER(vhdx_create_opts.head),
2212      .desc = {
2213          {
2214             .name = BLOCK_OPT_SIZE,
2215             .type = QEMU_OPT_SIZE,
2216             .help = "Virtual disk size; max of 64TB."
2217         },
2218         {
2219             .name = VHDX_BLOCK_OPT_LOG_SIZE,
2220             .type = QEMU_OPT_SIZE,
2221             .def_value_str = stringify(DEFAULT_LOG_SIZE),
2222             .help = "Log size; min 1MB."
2223         },
2224         {
2225             .name = VHDX_BLOCK_OPT_BLOCK_SIZE,
2226             .type = QEMU_OPT_SIZE,
2227             .def_value_str = stringify(0),
2228             .help = "Block Size; min 1MB, max 256MB. "
2229                     "0 means auto-calculate based on image size."
2230         },
2231         {
2232             .name = BLOCK_OPT_SUBFMT,
2233             .type = QEMU_OPT_STRING,
2234             .help = "VHDX format type, can be either 'dynamic' or 'fixed'. "
2235                     "Default is 'dynamic'."
2236         },
2237         {
2238             .name = VHDX_BLOCK_OPT_ZERO,
2239             .type = QEMU_OPT_BOOL,
2240             .help = "Force use of payload blocks of type 'ZERO'. "
2241                     "Non-standard, but default.  Do not set to 'off' when "
2242                     "using 'qemu-img convert' with subformat=dynamic."
2243         },
2244         { NULL }
2245      }
2246  };
2247  
2248  static BlockDriver bdrv_vhdx = {
2249      .format_name            = "vhdx",
2250      .instance_size          = sizeof(BDRVVHDXState),
2251      .bdrv_probe             = vhdx_probe,
2252      .bdrv_open              = vhdx_open,
2253      .bdrv_close             = vhdx_close,
2254      .bdrv_reopen_prepare    = vhdx_reopen_prepare,
2255      .bdrv_child_perm        = bdrv_default_perms,
2256      .bdrv_co_readv          = vhdx_co_readv,
2257      .bdrv_co_writev         = vhdx_co_writev,
2258      .bdrv_co_create         = vhdx_co_create,
2259      .bdrv_co_create_opts    = vhdx_co_create_opts,
2260      .bdrv_co_get_info       = vhdx_co_get_info,
2261      .bdrv_co_check          = vhdx_co_check,
2262      .bdrv_has_zero_init     = vhdx_has_zero_init,
2263  
2264      .is_format              = true,
2265      .create_opts            = &vhdx_create_opts,
2266  };
2267  
bdrv_vhdx_init(void)2268  static void bdrv_vhdx_init(void)
2269  {
2270      bdrv_register(&bdrv_vhdx);
2271  }
2272  
2273  block_init(bdrv_vhdx_init);
2274