xref: /openbmc/qemu/block/vhdx.c (revision 14a650ec)
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-common.h"
19 #include "block/block_int.h"
20 #include "qemu/module.h"
21 #include "qemu/crc32c.h"
22 #include "block/vhdx.h"
23 #include "migration/migration.h"
24 
25 #include <uuid/uuid.h>
26 #include <glib.h>
27 
28 /* Options for VHDX creation */
29 
30 #define VHDX_BLOCK_OPT_LOG_SIZE   "log_size"
31 #define VHDX_BLOCK_OPT_BLOCK_SIZE "block_size"
32 #define VHDX_BLOCK_OPT_ZERO "block_state_zero"
33 
34 typedef enum VHDXImageType {
35     VHDX_TYPE_DYNAMIC = 0,
36     VHDX_TYPE_FIXED,
37     VHDX_TYPE_DIFFERENCING,   /* Currently unsupported */
38 } VHDXImageType;
39 
40 /* Several metadata and region table data entries are identified by
41  * guids in  a MS-specific GUID format. */
42 
43 
44 /* ------- Known Region Table GUIDs ---------------------- */
45 static const MSGUID bat_guid =      { .data1 = 0x2dc27766,
46                                       .data2 = 0xf623,
47                                       .data3 = 0x4200,
48                                       .data4 = { 0x9d, 0x64, 0x11, 0x5e,
49                                                  0x9b, 0xfd, 0x4a, 0x08} };
50 
51 static const MSGUID metadata_guid = { .data1 = 0x8b7ca206,
52                                       .data2 = 0x4790,
53                                       .data3 = 0x4b9a,
54                                       .data4 = { 0xb8, 0xfe, 0x57, 0x5f,
55                                                  0x05, 0x0f, 0x88, 0x6e} };
56 
57 
58 
59 /* ------- Known Metadata Entry GUIDs ---------------------- */
60 static const MSGUID file_param_guid =   { .data1 = 0xcaa16737,
61                                           .data2 = 0xfa36,
62                                           .data3 = 0x4d43,
63                                           .data4 = { 0xb3, 0xb6, 0x33, 0xf0,
64                                                      0xaa, 0x44, 0xe7, 0x6b} };
65 
66 static const MSGUID virtual_size_guid = { .data1 = 0x2FA54224,
67                                           .data2 = 0xcd1b,
68                                           .data3 = 0x4876,
69                                           .data4 = { 0xb2, 0x11, 0x5d, 0xbe,
70                                                      0xd8, 0x3b, 0xf4, 0xb8} };
71 
72 static const MSGUID page83_guid =       { .data1 = 0xbeca12ab,
73                                           .data2 = 0xb2e6,
74                                           .data3 = 0x4523,
75                                           .data4 = { 0x93, 0xef, 0xc3, 0x09,
76                                                      0xe0, 0x00, 0xc7, 0x46} };
77 
78 
79 static const MSGUID phys_sector_guid =  { .data1 = 0xcda348c7,
80                                           .data2 = 0x445d,
81                                           .data3 = 0x4471,
82                                           .data4 = { 0x9c, 0xc9, 0xe9, 0x88,
83                                                      0x52, 0x51, 0xc5, 0x56} };
84 
85 static const MSGUID parent_locator_guid = { .data1 = 0xa8d35f2d,
86                                             .data2 = 0xb30b,
87                                             .data3 = 0x454d,
88                                             .data4 = { 0xab, 0xf7, 0xd3,
89                                                        0xd8, 0x48, 0x34,
90                                                        0xab, 0x0c} };
91 
92 static const MSGUID logical_sector_guid = { .data1 = 0x8141bf1d,
93                                             .data2 = 0xa96f,
94                                             .data3 = 0x4709,
95                                             .data4 = { 0xba, 0x47, 0xf2,
96                                                        0x33, 0xa8, 0xfa,
97                                                        0xab, 0x5f} };
98 
99 /* Each parent type must have a valid GUID; this is for parent images
100  * of type 'VHDX'.  If we were to allow e.g. a QCOW2 parent, we would
101  * need to make up our own QCOW2 GUID type */
102 static const MSGUID parent_vhdx_guid = { .data1 = 0xb04aefb7,
103                                          .data2 = 0xd19e,
104                                          .data3 = 0x4a81,
105                                          .data4 = { 0xb7, 0x89, 0x25, 0xb8,
106                                                     0xe9, 0x44, 0x59, 0x13} };
107 
108 
109 #define META_FILE_PARAMETER_PRESENT      0x01
110 #define META_VIRTUAL_DISK_SIZE_PRESENT   0x02
111 #define META_PAGE_83_PRESENT             0x04
112 #define META_LOGICAL_SECTOR_SIZE_PRESENT 0x08
113 #define META_PHYS_SECTOR_SIZE_PRESENT    0x10
114 #define META_PARENT_LOCATOR_PRESENT      0x20
115 
116 #define META_ALL_PRESENT    \
117     (META_FILE_PARAMETER_PRESENT | META_VIRTUAL_DISK_SIZE_PRESENT | \
118      META_PAGE_83_PRESENT | META_LOGICAL_SECTOR_SIZE_PRESENT | \
119      META_PHYS_SECTOR_SIZE_PRESENT)
120 
121 
122 typedef struct VHDXSectorInfo {
123     uint32_t bat_idx;       /* BAT entry index */
124     uint32_t sectors_avail; /* sectors available in payload block */
125     uint32_t bytes_left;    /* bytes left in the block after data to r/w */
126     uint32_t bytes_avail;   /* bytes available in payload block */
127     uint64_t file_offset;   /* absolute offset in bytes, in file */
128     uint64_t block_offset;  /* block offset, in bytes */
129 } VHDXSectorInfo;
130 
131 /* Calculates new checksum.
132  *
133  * Zero is substituted during crc calculation for the original crc field
134  * crc_offset: byte offset in buf of the buffer crc
135  * buf: buffer pointer
136  * size: size of buffer (must be > crc_offset+4)
137  *
138  * Note: The resulting checksum is in the CPU endianness, not necessarily
139  *       in the file format endianness (LE).  Any header export to disk should
140  *       make sure that vhdx_header_le_export() is used to convert to the
141  *       correct endianness
142  */
143 uint32_t vhdx_update_checksum(uint8_t *buf, size_t size, int crc_offset)
144 {
145     uint32_t crc;
146 
147     assert(buf != NULL);
148     assert(size > (crc_offset + sizeof(crc)));
149 
150     memset(buf + crc_offset, 0, sizeof(crc));
151     crc =  crc32c(0xffffffff, buf, size);
152     memcpy(buf + crc_offset, &crc, sizeof(crc));
153 
154     return crc;
155 }
156 
157 uint32_t vhdx_checksum_calc(uint32_t crc, uint8_t *buf, size_t size,
158                             int crc_offset)
159 {
160     uint32_t crc_new;
161     uint32_t crc_orig;
162     assert(buf != NULL);
163 
164     if (crc_offset > 0) {
165         memcpy(&crc_orig, buf + crc_offset, sizeof(crc_orig));
166         memset(buf + crc_offset, 0, sizeof(crc_orig));
167     }
168 
169     crc_new = crc32c(crc, buf, size);
170     if (crc_offset > 0) {
171         memcpy(buf + crc_offset, &crc_orig, sizeof(crc_orig));
172     }
173 
174     return crc_new;
175 }
176 
177 /* Validates the checksum of the buffer, with an in-place CRC.
178  *
179  * Zero is substituted during crc calculation for the original crc field,
180  * and the crc field is restored afterwards.  But the buffer will be modifed
181  * during the calculation, so this may not be not suitable for multi-threaded
182  * use.
183  *
184  * crc_offset: byte offset in buf of the buffer crc
185  * buf: buffer pointer
186  * size: size of buffer (must be > crc_offset+4)
187  *
188  * returns true if checksum is valid, false otherwise
189  */
190 bool vhdx_checksum_is_valid(uint8_t *buf, size_t size, int crc_offset)
191 {
192     uint32_t crc_orig;
193     uint32_t crc;
194 
195     assert(buf != NULL);
196     assert(size > (crc_offset + 4));
197 
198     memcpy(&crc_orig, buf + crc_offset, sizeof(crc_orig));
199     crc_orig = le32_to_cpu(crc_orig);
200 
201     crc = vhdx_checksum_calc(0xffffffff, buf, size, crc_offset);
202 
203     return crc == crc_orig;
204 }
205 
206 
207 /*
208  * This generates a UUID that is compliant with the MS GUIDs used
209  * in the VHDX spec (and elsewhere).
210  */
211 void vhdx_guid_generate(MSGUID *guid)
212 {
213     uuid_t uuid;
214     assert(guid != NULL);
215 
216     uuid_generate(uuid);
217     memcpy(guid, uuid, sizeof(MSGUID));
218 }
219 
220 /* Check for region overlaps inside the VHDX image */
221 static int vhdx_region_check(BDRVVHDXState *s, uint64_t start, uint64_t length)
222 {
223     int ret = 0;
224     uint64_t end;
225     VHDXRegionEntry *r;
226 
227     end = start + length;
228     QLIST_FOREACH(r, &s->regions, entries) {
229         if (!((start >= r->end) || (end <= r->start))) {
230             ret = -EINVAL;
231             goto exit;
232         }
233     }
234 
235 exit:
236     return ret;
237 }
238 
239 /* Register a region for future checks */
240 static void vhdx_region_register(BDRVVHDXState *s,
241                                  uint64_t start, uint64_t length)
242 {
243     VHDXRegionEntry *r;
244 
245     r = g_malloc0(sizeof(*r));
246 
247     r->start = start;
248     r->end = start + length;
249 
250     QLIST_INSERT_HEAD(&s->regions, r, entries);
251 }
252 
253 /* Free all registered regions */
254 static void vhdx_region_unregister_all(BDRVVHDXState *s)
255 {
256     VHDXRegionEntry *r, *r_next;
257 
258     QLIST_FOREACH_SAFE(r, &s->regions, entries, r_next) {
259         QLIST_REMOVE(r, entries);
260         g_free(r);
261     }
262 }
263 
264 static void vhdx_set_shift_bits(BDRVVHDXState *s)
265 {
266     s->logical_sector_size_bits = 31 - clz32(s->logical_sector_size);
267     s->sectors_per_block_bits =   31 - clz32(s->sectors_per_block);
268     s->chunk_ratio_bits =         63 - clz64(s->chunk_ratio);
269     s->block_size_bits =          31 - clz32(s->block_size);
270 }
271 
272 /*
273  * Per the MS VHDX Specification, for every VHDX file:
274  *      - The header section is fixed size - 1 MB
275  *      - The header section is always the first "object"
276  *      - The first 64KB of the header is the File Identifier
277  *      - The first uint64 (8 bytes) is the VHDX Signature ("vhdxfile")
278  *      - The following 512 bytes constitute a UTF-16 string identifiying the
279  *        software that created the file, and is optional and diagnostic only.
280  *
281  *  Therefore, we probe by looking for the vhdxfile signature "vhdxfile"
282  */
283 static int vhdx_probe(const uint8_t *buf, int buf_size, const char *filename)
284 {
285     if (buf_size >= 8 && !memcmp(buf, "vhdxfile", 8)) {
286         return 100;
287     }
288     return 0;
289 }
290 
291 /*
292  * Writes the header to the specified offset.
293  *
294  * This will optionally read in buffer data from disk (otherwise zero-fill),
295  * and then update the header checksum.  Header is converted to proper
296  * endianness before being written to the specified file offset
297  */
298 static int vhdx_write_header(BlockDriverState *bs_file, VHDXHeader *hdr,
299                              uint64_t offset, bool read)
300 {
301     uint8_t *buffer = NULL;
302     int ret;
303     VHDXHeader header_le;
304 
305     assert(bs_file != NULL);
306     assert(hdr != NULL);
307 
308     /* the header checksum is not over just the packed size of VHDXHeader,
309      * but rather over the entire 'reserved' range for the header, which is
310      * 4KB (VHDX_HEADER_SIZE). */
311 
312     buffer = qemu_blockalign(bs_file, VHDX_HEADER_SIZE);
313     if (read) {
314         /* if true, we can't assume the extra reserved bytes are 0 */
315         ret = bdrv_pread(bs_file, offset, buffer, VHDX_HEADER_SIZE);
316         if (ret < 0) {
317             goto exit;
318         }
319     } else {
320         memset(buffer, 0, VHDX_HEADER_SIZE);
321     }
322 
323     /* overwrite the actual VHDXHeader portion */
324     memcpy(buffer, hdr, sizeof(VHDXHeader));
325     hdr->checksum = vhdx_update_checksum(buffer, VHDX_HEADER_SIZE,
326                                          offsetof(VHDXHeader, checksum));
327     vhdx_header_le_export(hdr, &header_le);
328     ret = bdrv_pwrite_sync(bs_file, offset, &header_le, sizeof(VHDXHeader));
329 
330 exit:
331     qemu_vfree(buffer);
332     return ret;
333 }
334 
335 /* Update the VHDX headers
336  *
337  * This follows the VHDX spec procedures for header updates.
338  *
339  *  - non-current header is updated with largest sequence number
340  */
341 static int vhdx_update_header(BlockDriverState *bs, BDRVVHDXState *s,
342                               bool generate_data_write_guid, MSGUID *log_guid)
343 {
344     int ret = 0;
345     int hdr_idx = 0;
346     uint64_t header_offset = VHDX_HEADER1_OFFSET;
347 
348     VHDXHeader *active_header;
349     VHDXHeader *inactive_header;
350 
351     /* operate on the non-current header */
352     if (s->curr_header == 0) {
353         hdr_idx = 1;
354         header_offset = VHDX_HEADER2_OFFSET;
355     }
356 
357     active_header   = s->headers[s->curr_header];
358     inactive_header = s->headers[hdr_idx];
359 
360     inactive_header->sequence_number = active_header->sequence_number + 1;
361 
362     /* a new file guid must be generated before any file write, including
363      * headers */
364     inactive_header->file_write_guid = s->session_guid;
365 
366     /* a new data guid only needs to be generated before any guest-visible
367      * writes (i.e. something observable via virtual disk read) */
368     if (generate_data_write_guid) {
369         vhdx_guid_generate(&inactive_header->data_write_guid);
370     }
371 
372     /* update the log guid if present */
373     if (log_guid) {
374         inactive_header->log_guid = *log_guid;
375     }
376 
377     vhdx_write_header(bs->file, inactive_header, header_offset, true);
378     if (ret < 0) {
379         goto exit;
380     }
381     s->curr_header = hdr_idx;
382 
383 exit:
384     return ret;
385 }
386 
387 /*
388  * The VHDX spec calls for header updates to be performed twice, so that both
389  * the current and non-current header have valid info
390  */
391 int vhdx_update_headers(BlockDriverState *bs, BDRVVHDXState *s,
392                         bool generate_data_write_guid, MSGUID *log_guid)
393 {
394     int ret;
395 
396     ret = vhdx_update_header(bs, s, generate_data_write_guid, log_guid);
397     if (ret < 0) {
398         return ret;
399     }
400     ret = vhdx_update_header(bs, s, generate_data_write_guid, log_guid);
401     return ret;
402 }
403 
404 /* opens the specified header block from the VHDX file header section */
405 static int vhdx_parse_header(BlockDriverState *bs, BDRVVHDXState *s)
406 {
407     int ret = 0;
408     VHDXHeader *header1;
409     VHDXHeader *header2;
410     bool h1_valid = false;
411     bool h2_valid = false;
412     uint64_t h1_seq = 0;
413     uint64_t h2_seq = 0;
414     uint8_t *buffer;
415 
416     /* header1 & header2 are freed in vhdx_close() */
417     header1 = qemu_blockalign(bs, sizeof(VHDXHeader));
418     header2 = qemu_blockalign(bs, sizeof(VHDXHeader));
419 
420     buffer = qemu_blockalign(bs, VHDX_HEADER_SIZE);
421 
422     s->headers[0] = header1;
423     s->headers[1] = header2;
424 
425     /* We have to read the whole VHDX_HEADER_SIZE instead of
426      * sizeof(VHDXHeader), because the checksum is over the whole
427      * region */
428     ret = bdrv_pread(bs->file, VHDX_HEADER1_OFFSET, buffer, VHDX_HEADER_SIZE);
429     if (ret < 0) {
430         goto fail;
431     }
432     /* copy over just the relevant portion that we need */
433     memcpy(header1, buffer, sizeof(VHDXHeader));
434     vhdx_header_le_import(header1);
435 
436     if (vhdx_checksum_is_valid(buffer, VHDX_HEADER_SIZE, 4) &&
437         !memcmp(&header1->signature, "head", 4)             &&
438         header1->version == 1) {
439         h1_seq = header1->sequence_number;
440         h1_valid = true;
441     }
442 
443     ret = bdrv_pread(bs->file, VHDX_HEADER2_OFFSET, buffer, VHDX_HEADER_SIZE);
444     if (ret < 0) {
445         goto fail;
446     }
447     /* copy over just the relevant portion that we need */
448     memcpy(header2, buffer, sizeof(VHDXHeader));
449     vhdx_header_le_import(header2);
450 
451     if (vhdx_checksum_is_valid(buffer, VHDX_HEADER_SIZE, 4) &&
452         !memcmp(&header2->signature, "head", 4)             &&
453         header2->version == 1) {
454         h2_seq = header2->sequence_number;
455         h2_valid = true;
456     }
457 
458     /* If there is only 1 valid header (or no valid headers), we
459      * don't care what the sequence numbers are */
460     if (h1_valid && !h2_valid) {
461         s->curr_header = 0;
462     } else if (!h1_valid && h2_valid) {
463         s->curr_header = 1;
464     } else if (!h1_valid && !h2_valid) {
465         ret = -EINVAL;
466         goto fail;
467     } else {
468         /* If both headers are valid, then we choose the active one by the
469          * highest sequence number.  If the sequence numbers are equal, that is
470          * invalid */
471         if (h1_seq > h2_seq) {
472             s->curr_header = 0;
473         } else if (h2_seq > h1_seq) {
474             s->curr_header = 1;
475         } else {
476             ret = -EINVAL;
477             goto fail;
478         }
479     }
480 
481     vhdx_region_register(s, s->headers[s->curr_header]->log_offset,
482                             s->headers[s->curr_header]->log_length);
483 
484     ret = 0;
485 
486     goto exit;
487 
488 fail:
489     qerror_report(ERROR_CLASS_GENERIC_ERROR, "No valid VHDX header found");
490     qemu_vfree(header1);
491     qemu_vfree(header2);
492     s->headers[0] = NULL;
493     s->headers[1] = NULL;
494 exit:
495     qemu_vfree(buffer);
496     return ret;
497 }
498 
499 
500 static int vhdx_open_region_tables(BlockDriverState *bs, BDRVVHDXState *s)
501 {
502     int ret = 0;
503     uint8_t *buffer;
504     int offset = 0;
505     VHDXRegionTableEntry rt_entry;
506     uint32_t i;
507     bool bat_rt_found = false;
508     bool metadata_rt_found = false;
509 
510     /* We have to read the whole 64KB block, because the crc32 is over the
511      * whole block */
512     buffer = qemu_blockalign(bs, VHDX_HEADER_BLOCK_SIZE);
513 
514     ret = bdrv_pread(bs->file, VHDX_REGION_TABLE_OFFSET, buffer,
515                      VHDX_HEADER_BLOCK_SIZE);
516     if (ret < 0) {
517         goto fail;
518     }
519     memcpy(&s->rt, buffer, sizeof(s->rt));
520     vhdx_region_header_le_import(&s->rt);
521     offset += sizeof(s->rt);
522 
523     if (!vhdx_checksum_is_valid(buffer, VHDX_HEADER_BLOCK_SIZE, 4) ||
524         memcmp(&s->rt.signature, "regi", 4)) {
525         ret = -EINVAL;
526         goto fail;
527     }
528 
529     /* Per spec, maximum region table entry count is 2047 */
530     if (s->rt.entry_count > 2047) {
531         ret = -EINVAL;
532         goto fail;
533     }
534 
535     for (i = 0; i < s->rt.entry_count; i++) {
536         memcpy(&rt_entry, buffer + offset, sizeof(rt_entry));
537         offset += sizeof(rt_entry);
538 
539         vhdx_region_entry_le_import(&rt_entry);
540 
541         /* check for region overlap between these entries, and any
542          * other memory regions in the file */
543         ret = vhdx_region_check(s, rt_entry.file_offset, rt_entry.length);
544         if (ret < 0) {
545             goto fail;
546         }
547 
548         vhdx_region_register(s, rt_entry.file_offset, rt_entry.length);
549 
550         /* see if we recognize the entry */
551         if (guid_eq(rt_entry.guid, bat_guid)) {
552             /* must be unique; if we have already found it this is invalid */
553             if (bat_rt_found) {
554                 ret = -EINVAL;
555                 goto fail;
556             }
557             bat_rt_found = true;
558             s->bat_rt = rt_entry;
559             continue;
560         }
561 
562         if (guid_eq(rt_entry.guid, metadata_guid)) {
563             /* must be unique; if we have already found it this is invalid */
564             if (metadata_rt_found) {
565                 ret = -EINVAL;
566                 goto fail;
567             }
568             metadata_rt_found = true;
569             s->metadata_rt = rt_entry;
570             continue;
571         }
572 
573         if (rt_entry.data_bits & VHDX_REGION_ENTRY_REQUIRED) {
574             /* cannot read vhdx file - required region table entry that
575              * we do not understand.  per spec, we must fail to open */
576             ret = -ENOTSUP;
577             goto fail;
578         }
579     }
580 
581     if (!bat_rt_found || !metadata_rt_found) {
582         ret = -EINVAL;
583         goto fail;
584     }
585 
586     ret = 0;
587 
588 fail:
589     qemu_vfree(buffer);
590     return ret;
591 }
592 
593 
594 
595 /* Metadata initial parser
596  *
597  * This loads all the metadata entry fields.  This may cause additional
598  * fields to be processed (e.g. parent locator, etc..).
599  *
600  * There are 5 Metadata items that are always required:
601  *      - File Parameters (block size, has a parent)
602  *      - Virtual Disk Size (size, in bytes, of the virtual drive)
603  *      - Page 83 Data (scsi page 83 guid)
604  *      - Logical Sector Size (logical sector size in bytes, either 512 or
605  *                             4096.  We only support 512 currently)
606  *      - Physical Sector Size (512 or 4096)
607  *
608  * Also, if the File Parameters indicate this is a differencing file,
609  * we must also look for the Parent Locator metadata item.
610  */
611 static int vhdx_parse_metadata(BlockDriverState *bs, BDRVVHDXState *s)
612 {
613     int ret = 0;
614     uint8_t *buffer;
615     int offset = 0;
616     uint32_t i = 0;
617     VHDXMetadataTableEntry md_entry;
618 
619     buffer = qemu_blockalign(bs, VHDX_METADATA_TABLE_MAX_SIZE);
620 
621     ret = bdrv_pread(bs->file, s->metadata_rt.file_offset, buffer,
622                      VHDX_METADATA_TABLE_MAX_SIZE);
623     if (ret < 0) {
624         goto exit;
625     }
626     memcpy(&s->metadata_hdr, buffer, sizeof(s->metadata_hdr));
627     offset += sizeof(s->metadata_hdr);
628 
629     vhdx_metadata_header_le_import(&s->metadata_hdr);
630 
631     if (memcmp(&s->metadata_hdr.signature, "metadata", 8)) {
632         ret = -EINVAL;
633         goto exit;
634     }
635 
636     s->metadata_entries.present = 0;
637 
638     if ((s->metadata_hdr.entry_count * sizeof(md_entry)) >
639         (VHDX_METADATA_TABLE_MAX_SIZE - offset)) {
640         ret = -EINVAL;
641         goto exit;
642     }
643 
644     for (i = 0; i < s->metadata_hdr.entry_count; i++) {
645         memcpy(&md_entry, buffer + offset, sizeof(md_entry));
646         offset += sizeof(md_entry);
647 
648         vhdx_metadata_entry_le_import(&md_entry);
649 
650         if (guid_eq(md_entry.item_id, file_param_guid)) {
651             if (s->metadata_entries.present & META_FILE_PARAMETER_PRESENT) {
652                 ret = -EINVAL;
653                 goto exit;
654             }
655             s->metadata_entries.file_parameters_entry = md_entry;
656             s->metadata_entries.present |= META_FILE_PARAMETER_PRESENT;
657             continue;
658         }
659 
660         if (guid_eq(md_entry.item_id, virtual_size_guid)) {
661             if (s->metadata_entries.present & META_VIRTUAL_DISK_SIZE_PRESENT) {
662                 ret = -EINVAL;
663                 goto exit;
664             }
665             s->metadata_entries.virtual_disk_size_entry = md_entry;
666             s->metadata_entries.present |= META_VIRTUAL_DISK_SIZE_PRESENT;
667             continue;
668         }
669 
670         if (guid_eq(md_entry.item_id, page83_guid)) {
671             if (s->metadata_entries.present & META_PAGE_83_PRESENT) {
672                 ret = -EINVAL;
673                 goto exit;
674             }
675             s->metadata_entries.page83_data_entry = md_entry;
676             s->metadata_entries.present |= META_PAGE_83_PRESENT;
677             continue;
678         }
679 
680         if (guid_eq(md_entry.item_id, logical_sector_guid)) {
681             if (s->metadata_entries.present &
682                 META_LOGICAL_SECTOR_SIZE_PRESENT) {
683                 ret = -EINVAL;
684                 goto exit;
685             }
686             s->metadata_entries.logical_sector_size_entry = md_entry;
687             s->metadata_entries.present |= META_LOGICAL_SECTOR_SIZE_PRESENT;
688             continue;
689         }
690 
691         if (guid_eq(md_entry.item_id, phys_sector_guid)) {
692             if (s->metadata_entries.present & META_PHYS_SECTOR_SIZE_PRESENT) {
693                 ret = -EINVAL;
694                 goto exit;
695             }
696             s->metadata_entries.phys_sector_size_entry = md_entry;
697             s->metadata_entries.present |= META_PHYS_SECTOR_SIZE_PRESENT;
698             continue;
699         }
700 
701         if (guid_eq(md_entry.item_id, parent_locator_guid)) {
702             if (s->metadata_entries.present & META_PARENT_LOCATOR_PRESENT) {
703                 ret = -EINVAL;
704                 goto exit;
705             }
706             s->metadata_entries.parent_locator_entry = md_entry;
707             s->metadata_entries.present |= META_PARENT_LOCATOR_PRESENT;
708             continue;
709         }
710 
711         if (md_entry.data_bits & VHDX_META_FLAGS_IS_REQUIRED) {
712             /* cannot read vhdx file - required region table entry that
713              * we do not understand.  per spec, we must fail to open */
714             ret = -ENOTSUP;
715             goto exit;
716         }
717     }
718 
719     if (s->metadata_entries.present != META_ALL_PRESENT) {
720         ret = -ENOTSUP;
721         goto exit;
722     }
723 
724     ret = bdrv_pread(bs->file,
725                      s->metadata_entries.file_parameters_entry.offset
726                                          + s->metadata_rt.file_offset,
727                      &s->params,
728                      sizeof(s->params));
729 
730     if (ret < 0) {
731         goto exit;
732     }
733 
734     le32_to_cpus(&s->params.block_size);
735     le32_to_cpus(&s->params.data_bits);
736 
737 
738     /* We now have the file parameters, so we can tell if this is a
739      * differencing file (i.e.. has_parent), is dynamic or fixed
740      * sized (leave_blocks_allocated), and the block size */
741 
742     /* The parent locator required iff the file parameters has_parent set */
743     if (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) {
744         if (s->metadata_entries.present & META_PARENT_LOCATOR_PRESENT) {
745             /* TODO: parse  parent locator fields */
746             ret = -ENOTSUP; /* temp, until differencing files are supported */
747             goto exit;
748         } else {
749             /* if has_parent is set, but there is not parent locator present,
750              * then that is an invalid combination */
751             ret = -EINVAL;
752             goto exit;
753         }
754     }
755 
756     /* determine virtual disk size, logical sector size,
757      * and phys sector size */
758 
759     ret = bdrv_pread(bs->file,
760                      s->metadata_entries.virtual_disk_size_entry.offset
761                                            + s->metadata_rt.file_offset,
762                      &s->virtual_disk_size,
763                      sizeof(uint64_t));
764     if (ret < 0) {
765         goto exit;
766     }
767     ret = bdrv_pread(bs->file,
768                      s->metadata_entries.logical_sector_size_entry.offset
769                                              + s->metadata_rt.file_offset,
770                      &s->logical_sector_size,
771                      sizeof(uint32_t));
772     if (ret < 0) {
773         goto exit;
774     }
775     ret = bdrv_pread(bs->file,
776                      s->metadata_entries.phys_sector_size_entry.offset
777                                           + s->metadata_rt.file_offset,
778                      &s->physical_sector_size,
779                      sizeof(uint32_t));
780     if (ret < 0) {
781         goto exit;
782     }
783 
784     le64_to_cpus(&s->virtual_disk_size);
785     le32_to_cpus(&s->logical_sector_size);
786     le32_to_cpus(&s->physical_sector_size);
787 
788     if (s->logical_sector_size == 0 || s->params.block_size == 0) {
789         ret = -EINVAL;
790         goto exit;
791     }
792 
793     /* both block_size and sector_size are guaranteed powers of 2 */
794     s->sectors_per_block = s->params.block_size / s->logical_sector_size;
795     s->chunk_ratio = (VHDX_MAX_SECTORS_PER_BLOCK) *
796                      (uint64_t)s->logical_sector_size /
797                      (uint64_t)s->params.block_size;
798 
799     /* These values are ones we will want to use for division / multiplication
800      * later on, and they are all guaranteed (per the spec) to be powers of 2,
801      * so we can take advantage of that for shift operations during
802      * reads/writes */
803     if (s->logical_sector_size & (s->logical_sector_size - 1)) {
804         ret = -EINVAL;
805         goto exit;
806     }
807     if (s->sectors_per_block & (s->sectors_per_block - 1)) {
808         ret = -EINVAL;
809         goto exit;
810     }
811     if (s->chunk_ratio & (s->chunk_ratio - 1)) {
812         ret = -EINVAL;
813         goto exit;
814     }
815     s->block_size = s->params.block_size;
816     if (s->block_size & (s->block_size - 1)) {
817         ret = -EINVAL;
818         goto exit;
819     }
820 
821     vhdx_set_shift_bits(s);
822 
823     ret = 0;
824 
825 exit:
826     qemu_vfree(buffer);
827     return ret;
828 }
829 
830 /*
831  * Calculate the number of BAT entries, including sector
832  * bitmap entries.
833  */
834 static void vhdx_calc_bat_entries(BDRVVHDXState *s)
835 {
836     uint32_t data_blocks_cnt, bitmap_blocks_cnt;
837 
838     data_blocks_cnt = s->virtual_disk_size >> s->block_size_bits;
839     if (s->virtual_disk_size - (data_blocks_cnt << s->block_size_bits)) {
840         data_blocks_cnt++;
841     }
842     bitmap_blocks_cnt = data_blocks_cnt >> s->chunk_ratio_bits;
843     if (data_blocks_cnt - (bitmap_blocks_cnt << s->chunk_ratio_bits)) {
844         bitmap_blocks_cnt++;
845     }
846 
847     if (s->parent_entries) {
848         s->bat_entries = bitmap_blocks_cnt * (s->chunk_ratio + 1);
849     } else {
850         s->bat_entries = data_blocks_cnt +
851                          ((data_blocks_cnt - 1) >> s->chunk_ratio_bits);
852     }
853 
854 }
855 
856 static void vhdx_close(BlockDriverState *bs)
857 {
858     BDRVVHDXState *s = bs->opaque;
859     qemu_vfree(s->headers[0]);
860     s->headers[0] = NULL;
861     qemu_vfree(s->headers[1]);
862     s->headers[1] = NULL;
863     qemu_vfree(s->bat);
864     s->bat = NULL;
865     qemu_vfree(s->parent_entries);
866     s->parent_entries = NULL;
867     migrate_del_blocker(s->migration_blocker);
868     error_free(s->migration_blocker);
869     qemu_vfree(s->log.hdr);
870     s->log.hdr = NULL;
871     vhdx_region_unregister_all(s);
872 }
873 
874 static int vhdx_open(BlockDriverState *bs, QDict *options, int flags,
875                      Error **errp)
876 {
877     BDRVVHDXState *s = bs->opaque;
878     int ret = 0;
879     uint32_t i;
880     uint64_t signature;
881     bool log_flushed = false;
882 
883 
884     s->bat = NULL;
885     s->first_visible_write = true;
886 
887     qemu_co_mutex_init(&s->lock);
888     QLIST_INIT(&s->regions);
889 
890     /* validate the file signature */
891     ret = bdrv_pread(bs->file, 0, &signature, sizeof(uint64_t));
892     if (ret < 0) {
893         goto fail;
894     }
895     if (memcmp(&signature, "vhdxfile", 8)) {
896         ret = -EINVAL;
897         goto fail;
898     }
899 
900     /* This is used for any header updates, for the file_write_guid.
901      * The spec dictates that a new value should be used for the first
902      * header update */
903     vhdx_guid_generate(&s->session_guid);
904 
905     ret = vhdx_parse_header(bs, s);
906     if (ret < 0) {
907         goto fail;
908     }
909 
910     ret = vhdx_parse_log(bs, s, &log_flushed);
911     if (ret < 0) {
912         goto fail;
913     }
914 
915     ret = vhdx_open_region_tables(bs, s);
916     if (ret < 0) {
917         goto fail;
918     }
919 
920     ret = vhdx_parse_metadata(bs, s);
921     if (ret < 0) {
922         goto fail;
923     }
924 
925     s->block_size = s->params.block_size;
926 
927     /* the VHDX spec dictates that virtual_disk_size is always a multiple of
928      * logical_sector_size */
929     bs->total_sectors = s->virtual_disk_size >> s->logical_sector_size_bits;
930 
931     vhdx_calc_bat_entries(s);
932 
933     s->bat_offset = s->bat_rt.file_offset;
934 
935     if (s->bat_entries > s->bat_rt.length / sizeof(VHDXBatEntry)) {
936         /* BAT allocation is not large enough for all entries */
937         ret = -EINVAL;
938         goto fail;
939     }
940 
941     /* s->bat is freed in vhdx_close() */
942     s->bat = qemu_blockalign(bs, s->bat_rt.length);
943 
944     ret = bdrv_pread(bs->file, s->bat_offset, s->bat, s->bat_rt.length);
945     if (ret < 0) {
946         goto fail;
947     }
948 
949     uint64_t payblocks = s->chunk_ratio;
950     /* endian convert, and verify populated BAT field file offsets against
951      * region table and log entries */
952     for (i = 0; i < s->bat_entries; i++) {
953         le64_to_cpus(&s->bat[i]);
954         if (payblocks--) {
955             /* payload bat entries */
956             if ((s->bat[i] & VHDX_BAT_STATE_BIT_MASK) ==
957                     PAYLOAD_BLOCK_FULLY_PRESENT) {
958                 ret = vhdx_region_check(s, s->bat[i] & VHDX_BAT_FILE_OFF_MASK,
959                                         s->block_size);
960                 if (ret < 0) {
961                     goto fail;
962                 }
963             }
964         } else {
965             payblocks = s->chunk_ratio;
966             /* Once differencing files are supported, verify sector bitmap
967              * blocks here */
968         }
969     }
970 
971     if (flags & BDRV_O_RDWR) {
972         ret = vhdx_update_headers(bs, s, false, NULL);
973         if (ret < 0) {
974             goto fail;
975         }
976     }
977 
978     /* TODO: differencing files */
979 
980     /* Disable migration when VHDX images are used */
981     error_set(&s->migration_blocker,
982             QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
983             "vhdx", bs->device_name, "live migration");
984     migrate_add_blocker(s->migration_blocker);
985 
986     return 0;
987 fail:
988     vhdx_close(bs);
989     return ret;
990 }
991 
992 static int vhdx_reopen_prepare(BDRVReopenState *state,
993                                BlockReopenQueue *queue, Error **errp)
994 {
995     return 0;
996 }
997 
998 
999 /*
1000  * Perform sector to block offset translations, to get various
1001  * sector and file offsets into the image.  See VHDXSectorInfo
1002  */
1003 static void vhdx_block_translate(BDRVVHDXState *s, int64_t sector_num,
1004                                  int nb_sectors, VHDXSectorInfo *sinfo)
1005 {
1006     uint32_t block_offset;
1007 
1008     sinfo->bat_idx = sector_num >> s->sectors_per_block_bits;
1009     /* effectively a modulo - this gives us the offset into the block
1010      * (in sector sizes) for our sector number */
1011     block_offset = sector_num - (sinfo->bat_idx << s->sectors_per_block_bits);
1012     /* the chunk ratio gives us the interleaving of the sector
1013      * bitmaps, so we need to advance our page block index by the
1014      * sector bitmaps entry number */
1015     sinfo->bat_idx += sinfo->bat_idx >> s->chunk_ratio_bits;
1016 
1017     /* the number of sectors we can read/write in this cycle */
1018     sinfo->sectors_avail = s->sectors_per_block - block_offset;
1019 
1020     sinfo->bytes_left = sinfo->sectors_avail << s->logical_sector_size_bits;
1021 
1022     if (sinfo->sectors_avail > nb_sectors) {
1023         sinfo->sectors_avail = nb_sectors;
1024     }
1025 
1026     sinfo->bytes_avail = sinfo->sectors_avail << s->logical_sector_size_bits;
1027 
1028     sinfo->file_offset = s->bat[sinfo->bat_idx] & VHDX_BAT_FILE_OFF_MASK;
1029 
1030     sinfo->block_offset = block_offset << s->logical_sector_size_bits;
1031 
1032     /* The file offset must be past the header section, so must be > 0 */
1033     if (sinfo->file_offset == 0) {
1034         return;
1035     }
1036 
1037     /* block offset is the offset in vhdx logical sectors, in
1038      * the payload data block. Convert that to a byte offset
1039      * in the block, and add in the payload data block offset
1040      * in the file, in bytes, to get the final read address */
1041 
1042     sinfo->file_offset += sinfo->block_offset;
1043 }
1044 
1045 
1046 
1047 static coroutine_fn int vhdx_co_readv(BlockDriverState *bs, int64_t sector_num,
1048                                       int nb_sectors, QEMUIOVector *qiov)
1049 {
1050     BDRVVHDXState *s = bs->opaque;
1051     int ret = 0;
1052     VHDXSectorInfo sinfo;
1053     uint64_t bytes_done = 0;
1054     QEMUIOVector hd_qiov;
1055 
1056     qemu_iovec_init(&hd_qiov, qiov->niov);
1057 
1058     qemu_co_mutex_lock(&s->lock);
1059 
1060     while (nb_sectors > 0) {
1061         /* We are a differencing file, so we need to inspect the sector bitmap
1062          * to see if we have the data or not */
1063         if (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) {
1064             /* not supported yet */
1065             ret = -ENOTSUP;
1066             goto exit;
1067         } else {
1068             vhdx_block_translate(s, sector_num, nb_sectors, &sinfo);
1069 
1070             qemu_iovec_reset(&hd_qiov);
1071             qemu_iovec_concat(&hd_qiov, qiov,  bytes_done, sinfo.bytes_avail);
1072 
1073             /* check the payload block state */
1074             switch (s->bat[sinfo.bat_idx] & VHDX_BAT_STATE_BIT_MASK) {
1075             case PAYLOAD_BLOCK_NOT_PRESENT: /* fall through */
1076             case PAYLOAD_BLOCK_UNDEFINED:   /* fall through */
1077             case PAYLOAD_BLOCK_UNMAPPED:    /* fall through */
1078             case PAYLOAD_BLOCK_ZERO:
1079                 /* return zero */
1080                 qemu_iovec_memset(&hd_qiov, 0, 0, sinfo.bytes_avail);
1081                 break;
1082             case PAYLOAD_BLOCK_FULLY_PRESENT:
1083                 qemu_co_mutex_unlock(&s->lock);
1084                 ret = bdrv_co_readv(bs->file,
1085                                     sinfo.file_offset >> BDRV_SECTOR_BITS,
1086                                     sinfo.sectors_avail, &hd_qiov);
1087                 qemu_co_mutex_lock(&s->lock);
1088                 if (ret < 0) {
1089                     goto exit;
1090                 }
1091                 break;
1092             case PAYLOAD_BLOCK_PARTIALLY_PRESENT:
1093                 /* we don't yet support difference files, fall through
1094                  * to error */
1095             default:
1096                 ret = -EIO;
1097                 goto exit;
1098                 break;
1099             }
1100             nb_sectors -= sinfo.sectors_avail;
1101             sector_num += sinfo.sectors_avail;
1102             bytes_done += sinfo.bytes_avail;
1103         }
1104     }
1105     ret = 0;
1106 exit:
1107     qemu_co_mutex_unlock(&s->lock);
1108     qemu_iovec_destroy(&hd_qiov);
1109     return ret;
1110 }
1111 
1112 /*
1113  * Allocate a new payload block at the end of the file.
1114  *
1115  * Allocation will happen at 1MB alignment inside the file
1116  *
1117  * Returns the file offset start of the new payload block
1118  */
1119 static int vhdx_allocate_block(BlockDriverState *bs, BDRVVHDXState *s,
1120                                     uint64_t *new_offset)
1121 {
1122     *new_offset = bdrv_getlength(bs->file);
1123 
1124     /* per the spec, the address for a block is in units of 1MB */
1125     *new_offset = ROUND_UP(*new_offset, 1024 * 1024);
1126 
1127     return bdrv_truncate(bs->file, *new_offset + s->block_size);
1128 }
1129 
1130 /*
1131  * Update the BAT table entry with the new file offset, and the new entry
1132  * state */
1133 static void vhdx_update_bat_table_entry(BlockDriverState *bs, BDRVVHDXState *s,
1134                                        VHDXSectorInfo *sinfo,
1135                                        uint64_t *bat_entry_le,
1136                                        uint64_t *bat_offset, int state)
1137 {
1138     /* The BAT entry is a uint64, with 44 bits for the file offset in units of
1139      * 1MB, and 3 bits for the block state. */
1140     s->bat[sinfo->bat_idx]  = sinfo->file_offset;
1141 
1142     s->bat[sinfo->bat_idx] |= state & VHDX_BAT_STATE_BIT_MASK;
1143 
1144     *bat_entry_le = cpu_to_le64(s->bat[sinfo->bat_idx]);
1145     *bat_offset = s->bat_offset + sinfo->bat_idx * sizeof(VHDXBatEntry);
1146 
1147 }
1148 
1149 /* Per the spec, on the first write of guest-visible data to the file the
1150  * data write guid must be updated in the header */
1151 int vhdx_user_visible_write(BlockDriverState *bs, BDRVVHDXState *s)
1152 {
1153     int ret = 0;
1154     if (s->first_visible_write) {
1155         s->first_visible_write = false;
1156         ret = vhdx_update_headers(bs, s, true, NULL);
1157     }
1158     return ret;
1159 }
1160 
1161 static coroutine_fn int vhdx_co_writev(BlockDriverState *bs, int64_t sector_num,
1162                                       int nb_sectors, QEMUIOVector *qiov)
1163 {
1164     int ret = -ENOTSUP;
1165     BDRVVHDXState *s = bs->opaque;
1166     VHDXSectorInfo sinfo;
1167     uint64_t bytes_done = 0;
1168     uint64_t bat_entry = 0;
1169     uint64_t bat_entry_offset = 0;
1170     QEMUIOVector hd_qiov;
1171     struct iovec iov1 = { 0 };
1172     struct iovec iov2 = { 0 };
1173     int sectors_to_write;
1174     int bat_state;
1175     uint64_t bat_prior_offset = 0;
1176     bool bat_update = false;
1177 
1178     qemu_iovec_init(&hd_qiov, qiov->niov);
1179 
1180     qemu_co_mutex_lock(&s->lock);
1181 
1182     ret = vhdx_user_visible_write(bs, s);
1183     if (ret < 0) {
1184         goto exit;
1185     }
1186 
1187     while (nb_sectors > 0) {
1188         bool use_zero_buffers = false;
1189         bat_update = false;
1190         if (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) {
1191             /* not supported yet */
1192             ret = -ENOTSUP;
1193             goto exit;
1194         } else {
1195             vhdx_block_translate(s, sector_num, nb_sectors, &sinfo);
1196             sectors_to_write = sinfo.sectors_avail;
1197 
1198             qemu_iovec_reset(&hd_qiov);
1199             /* check the payload block state */
1200             bat_state = s->bat[sinfo.bat_idx] & VHDX_BAT_STATE_BIT_MASK;
1201             switch (bat_state) {
1202             case PAYLOAD_BLOCK_ZERO:
1203                 /* in this case, we need to preserve zero writes for
1204                  * data that is not part of this write, so we must pad
1205                  * the rest of the buffer to zeroes */
1206 
1207                 /* if we are on a posix system with ftruncate() that extends
1208                  * a file, then it is zero-filled for us.  On Win32, the raw
1209                  * layer uses SetFilePointer and SetFileEnd, which does not
1210                  * zero fill AFAIK */
1211 
1212                 /* Queue another write of zero buffers if the underlying file
1213                  * does not zero-fill on file extension */
1214 
1215                 if (bdrv_has_zero_init(bs->file) == 0) {
1216                     use_zero_buffers = true;
1217 
1218                     /* zero fill the front, if any */
1219                     if (sinfo.block_offset) {
1220                         iov1.iov_len = sinfo.block_offset;
1221                         iov1.iov_base = qemu_blockalign(bs, iov1.iov_len);
1222                         memset(iov1.iov_base, 0, iov1.iov_len);
1223                         qemu_iovec_concat_iov(&hd_qiov, &iov1, 1, 0,
1224                                               sinfo.block_offset);
1225                         sectors_to_write += iov1.iov_len >> BDRV_SECTOR_BITS;
1226                     }
1227 
1228                     /* our actual data */
1229                     qemu_iovec_concat(&hd_qiov, qiov,  bytes_done,
1230                                       sinfo.bytes_avail);
1231 
1232                     /* zero fill the back, if any */
1233                     if ((sinfo.bytes_avail - sinfo.block_offset) <
1234                          s->block_size) {
1235                         iov2.iov_len = s->block_size -
1236                                       (sinfo.bytes_avail + sinfo.block_offset);
1237                         iov2.iov_base = qemu_blockalign(bs, iov2.iov_len);
1238                         memset(iov2.iov_base, 0, iov2.iov_len);
1239                         qemu_iovec_concat_iov(&hd_qiov, &iov2, 1, 0,
1240                                               sinfo.block_offset);
1241                         sectors_to_write += iov2.iov_len >> BDRV_SECTOR_BITS;
1242                     }
1243                 }
1244 
1245                 /* fall through */
1246             case PAYLOAD_BLOCK_NOT_PRESENT: /* fall through */
1247             case PAYLOAD_BLOCK_UNMAPPED:    /* fall through */
1248             case PAYLOAD_BLOCK_UNDEFINED:   /* fall through */
1249                 bat_prior_offset = sinfo.file_offset;
1250                 ret = vhdx_allocate_block(bs, s, &sinfo.file_offset);
1251                 if (ret < 0) {
1252                     goto exit;
1253                 }
1254                 /* once we support differencing files, this may also be
1255                  * partially present */
1256                 /* update block state to the newly specified state */
1257                 vhdx_update_bat_table_entry(bs, s, &sinfo, &bat_entry,
1258                                             &bat_entry_offset,
1259                                             PAYLOAD_BLOCK_FULLY_PRESENT);
1260                 bat_update = true;
1261                 /* since we just allocated a block, file_offset is the
1262                  * beginning of the payload block. It needs to be the
1263                  * write address, which includes the offset into the block */
1264                 if (!use_zero_buffers) {
1265                     sinfo.file_offset += sinfo.block_offset;
1266                 }
1267                 /* fall through */
1268             case PAYLOAD_BLOCK_FULLY_PRESENT:
1269                 /* if the file offset address is in the header zone,
1270                  * there is a problem */
1271                 if (sinfo.file_offset < (1024 * 1024)) {
1272                     ret = -EFAULT;
1273                     goto error_bat_restore;
1274                 }
1275 
1276                 if (!use_zero_buffers) {
1277                     qemu_iovec_concat(&hd_qiov, qiov,  bytes_done,
1278                                       sinfo.bytes_avail);
1279                 }
1280                 /* block exists, so we can just overwrite it */
1281                 qemu_co_mutex_unlock(&s->lock);
1282                 ret = bdrv_co_writev(bs->file,
1283                                     sinfo.file_offset >> BDRV_SECTOR_BITS,
1284                                     sectors_to_write, &hd_qiov);
1285                 qemu_co_mutex_lock(&s->lock);
1286                 if (ret < 0) {
1287                     goto error_bat_restore;
1288                 }
1289                 break;
1290             case PAYLOAD_BLOCK_PARTIALLY_PRESENT:
1291                 /* we don't yet support difference files, fall through
1292                  * to error */
1293             default:
1294                 ret = -EIO;
1295                 goto exit;
1296                 break;
1297             }
1298 
1299             if (bat_update) {
1300                 /* this will update the BAT entry into the log journal, and
1301                  * then flush the log journal out to disk */
1302                 ret =  vhdx_log_write_and_flush(bs, s, &bat_entry,
1303                                                 sizeof(VHDXBatEntry),
1304                                                 bat_entry_offset);
1305                 if (ret < 0) {
1306                     goto exit;
1307                 }
1308             }
1309 
1310             nb_sectors -= sinfo.sectors_avail;
1311             sector_num += sinfo.sectors_avail;
1312             bytes_done += sinfo.bytes_avail;
1313 
1314         }
1315     }
1316 
1317     goto exit;
1318 
1319 error_bat_restore:
1320     if (bat_update) {
1321         /* keep metadata in sync, and restore the bat entry state
1322          * if error. */
1323         sinfo.file_offset = bat_prior_offset;
1324         vhdx_update_bat_table_entry(bs, s, &sinfo, &bat_entry,
1325                                     &bat_entry_offset, bat_state);
1326     }
1327 exit:
1328     qemu_vfree(iov1.iov_base);
1329     qemu_vfree(iov2.iov_base);
1330     qemu_co_mutex_unlock(&s->lock);
1331     qemu_iovec_destroy(&hd_qiov);
1332     return ret;
1333 }
1334 
1335 
1336 
1337 /*
1338  * Create VHDX Headers
1339  *
1340  * There are 2 headers, and the highest sequence number will represent
1341  * the active header
1342  */
1343 static int vhdx_create_new_headers(BlockDriverState *bs, uint64_t image_size,
1344                                    uint32_t log_size)
1345 {
1346     int ret = 0;
1347     VHDXHeader *hdr = NULL;
1348 
1349     hdr = g_malloc0(sizeof(VHDXHeader));
1350 
1351     hdr->signature       = VHDX_HEADER_SIGNATURE;
1352     hdr->sequence_number = g_random_int();
1353     hdr->log_version     = 0;
1354     hdr->version         = 1;
1355     hdr->log_length      = log_size;
1356     hdr->log_offset      = VHDX_HEADER_SECTION_END;
1357     vhdx_guid_generate(&hdr->file_write_guid);
1358     vhdx_guid_generate(&hdr->data_write_guid);
1359 
1360     ret = vhdx_write_header(bs, hdr, VHDX_HEADER1_OFFSET, false);
1361     if (ret < 0) {
1362         goto exit;
1363     }
1364     hdr->sequence_number++;
1365     ret = vhdx_write_header(bs, hdr, VHDX_HEADER2_OFFSET, false);
1366     if (ret < 0) {
1367         goto exit;
1368     }
1369 
1370 exit:
1371     g_free(hdr);
1372     return ret;
1373 }
1374 
1375 
1376 /*
1377  * Create the Metadata entries.
1378  *
1379  * For more details on the entries, see section 3.5 (pg 29) in the
1380  * VHDX 1.00 specification.
1381  *
1382  * We support 5 metadata entries (all required by spec):
1383  *          File Parameters,
1384  *          Virtual Disk Size,
1385  *          Page 83 Data,
1386  *          Logical Sector Size,
1387  *          Physical Sector Size
1388  *
1389  * The first 64KB of the Metadata section is reserved for the metadata
1390  * header and entries; beyond that, the metadata items themselves reside.
1391  */
1392 static int vhdx_create_new_metadata(BlockDriverState *bs,
1393                                     uint64_t image_size,
1394                                     uint32_t block_size,
1395                                     uint32_t sector_size,
1396                                     uint64_t metadata_offset,
1397                                     VHDXImageType type)
1398 {
1399     int ret = 0;
1400     uint32_t offset = 0;
1401     void *buffer = NULL;
1402     void *entry_buffer;
1403     VHDXMetadataTableHeader *md_table;;
1404     VHDXMetadataTableEntry  *md_table_entry;
1405 
1406     /* Metadata entries */
1407     VHDXFileParameters     *mt_file_params;
1408     VHDXVirtualDiskSize    *mt_virtual_size;
1409     VHDXPage83Data         *mt_page83;
1410     VHDXVirtualDiskLogicalSectorSize  *mt_log_sector_size;
1411     VHDXVirtualDiskPhysicalSectorSize *mt_phys_sector_size;
1412 
1413     entry_buffer = g_malloc0(sizeof(VHDXFileParameters)               +
1414                              sizeof(VHDXVirtualDiskSize)              +
1415                              sizeof(VHDXPage83Data)                   +
1416                              sizeof(VHDXVirtualDiskLogicalSectorSize) +
1417                              sizeof(VHDXVirtualDiskPhysicalSectorSize));
1418 
1419     mt_file_params = entry_buffer;
1420     offset += sizeof(VHDXFileParameters);
1421     mt_virtual_size = entry_buffer + offset;
1422     offset += sizeof(VHDXVirtualDiskSize);
1423     mt_page83 = entry_buffer + offset;
1424     offset += sizeof(VHDXPage83Data);
1425     mt_log_sector_size = entry_buffer + offset;
1426     offset += sizeof(VHDXVirtualDiskLogicalSectorSize);
1427     mt_phys_sector_size = entry_buffer + offset;
1428 
1429     mt_file_params->block_size = cpu_to_le32(block_size);
1430     if (type == VHDX_TYPE_FIXED) {
1431         mt_file_params->data_bits |= VHDX_PARAMS_LEAVE_BLOCKS_ALLOCED;
1432         cpu_to_le32s(&mt_file_params->data_bits);
1433     }
1434 
1435     vhdx_guid_generate(&mt_page83->page_83_data);
1436     cpu_to_leguids(&mt_page83->page_83_data);
1437     mt_virtual_size->virtual_disk_size        = cpu_to_le64(image_size);
1438     mt_log_sector_size->logical_sector_size   = cpu_to_le32(sector_size);
1439     mt_phys_sector_size->physical_sector_size = cpu_to_le32(sector_size);
1440 
1441     buffer = g_malloc0(VHDX_HEADER_BLOCK_SIZE);
1442     md_table = buffer;
1443 
1444     md_table->signature   = VHDX_METADATA_SIGNATURE;
1445     md_table->entry_count = 5;
1446     vhdx_metadata_header_le_export(md_table);
1447 
1448 
1449     /* This will reference beyond the reserved table portion */
1450     offset = 64 * KiB;
1451 
1452     md_table_entry = buffer + sizeof(VHDXMetadataTableHeader);
1453 
1454     md_table_entry[0].item_id = file_param_guid;
1455     md_table_entry[0].offset  = offset;
1456     md_table_entry[0].length  = sizeof(VHDXFileParameters);
1457     md_table_entry[0].data_bits |= VHDX_META_FLAGS_IS_REQUIRED;
1458     offset += md_table_entry[0].length;
1459     vhdx_metadata_entry_le_export(&md_table_entry[0]);
1460 
1461     md_table_entry[1].item_id = virtual_size_guid;
1462     md_table_entry[1].offset  = offset;
1463     md_table_entry[1].length  = sizeof(VHDXVirtualDiskSize);
1464     md_table_entry[1].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
1465                                    VHDX_META_FLAGS_IS_VIRTUAL_DISK;
1466     offset += md_table_entry[1].length;
1467     vhdx_metadata_entry_le_export(&md_table_entry[1]);
1468 
1469     md_table_entry[2].item_id = page83_guid;
1470     md_table_entry[2].offset  = offset;
1471     md_table_entry[2].length  = sizeof(VHDXPage83Data);
1472     md_table_entry[2].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
1473                                    VHDX_META_FLAGS_IS_VIRTUAL_DISK;
1474     offset += md_table_entry[2].length;
1475     vhdx_metadata_entry_le_export(&md_table_entry[2]);
1476 
1477     md_table_entry[3].item_id = logical_sector_guid;
1478     md_table_entry[3].offset  = offset;
1479     md_table_entry[3].length  = sizeof(VHDXVirtualDiskLogicalSectorSize);
1480     md_table_entry[3].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
1481                                    VHDX_META_FLAGS_IS_VIRTUAL_DISK;
1482     offset += md_table_entry[3].length;
1483     vhdx_metadata_entry_le_export(&md_table_entry[3]);
1484 
1485     md_table_entry[4].item_id = phys_sector_guid;
1486     md_table_entry[4].offset  = offset;
1487     md_table_entry[4].length  = sizeof(VHDXVirtualDiskPhysicalSectorSize);
1488     md_table_entry[4].data_bits |= VHDX_META_FLAGS_IS_REQUIRED |
1489                                    VHDX_META_FLAGS_IS_VIRTUAL_DISK;
1490     vhdx_metadata_entry_le_export(&md_table_entry[4]);
1491 
1492     ret = bdrv_pwrite(bs, metadata_offset, buffer, VHDX_HEADER_BLOCK_SIZE);
1493     if (ret < 0) {
1494         goto exit;
1495     }
1496 
1497     ret = bdrv_pwrite(bs, metadata_offset + (64 * KiB), entry_buffer,
1498                       VHDX_HEADER_BLOCK_SIZE);
1499     if (ret < 0) {
1500         goto exit;
1501     }
1502 
1503 
1504 exit:
1505     g_free(buffer);
1506     g_free(entry_buffer);
1507     return ret;
1508 }
1509 
1510 /* This create the actual BAT itself.  We currently only support
1511  * 'Dynamic' and 'Fixed' image types.
1512  *
1513  *  Dynamic images: default state of the BAT is all zeroes.
1514  *
1515  *  Fixed images: default state of the BAT is fully populated, with
1516  *                file offsets and state PAYLOAD_BLOCK_FULLY_PRESENT.
1517  */
1518 static int vhdx_create_bat(BlockDriverState *bs, BDRVVHDXState *s,
1519                            uint64_t image_size, VHDXImageType type,
1520                            bool use_zero_blocks, VHDXRegionTableEntry *rt_bat)
1521 {
1522     int ret = 0;
1523     uint64_t data_file_offset;
1524     uint64_t total_sectors = 0;
1525     uint64_t sector_num = 0;
1526     uint64_t unused;
1527     int block_state;
1528     VHDXSectorInfo sinfo;
1529 
1530     assert(s->bat == NULL);
1531 
1532     /* this gives a data start after BAT/bitmap entries, and well
1533      * past any metadata entries (with a 4 MB buffer for future
1534      * expansion */
1535     data_file_offset = rt_bat->file_offset + rt_bat->length + 5 * MiB;
1536     total_sectors = image_size >> s->logical_sector_size_bits;
1537 
1538     if (type == VHDX_TYPE_DYNAMIC) {
1539         /* All zeroes, so we can just extend the file - the end of the BAT
1540          * is the furthest thing we have written yet */
1541         ret = bdrv_truncate(bs, data_file_offset);
1542         if (ret < 0) {
1543             goto exit;
1544         }
1545     } else if (type == VHDX_TYPE_FIXED) {
1546         ret = bdrv_truncate(bs, data_file_offset + image_size);
1547         if (ret < 0) {
1548             goto exit;
1549         }
1550     } else {
1551         ret = -ENOTSUP;
1552         goto exit;
1553     }
1554 
1555     if (type == VHDX_TYPE_FIXED ||
1556                 use_zero_blocks ||
1557                 bdrv_has_zero_init(bs) == 0) {
1558         /* for a fixed file, the default BAT entry is not zero */
1559         s->bat = g_malloc0(rt_bat->length);
1560         block_state = type == VHDX_TYPE_FIXED ? PAYLOAD_BLOCK_FULLY_PRESENT :
1561                                                 PAYLOAD_BLOCK_NOT_PRESENT;
1562         block_state = use_zero_blocks ? PAYLOAD_BLOCK_ZERO : block_state;
1563         /* fill the BAT by emulating sector writes of sectors_per_block size */
1564         while (sector_num < total_sectors) {
1565             vhdx_block_translate(s, sector_num, s->sectors_per_block, &sinfo);
1566             sinfo.file_offset = data_file_offset +
1567                                 (sector_num << s->logical_sector_size_bits);
1568             sinfo.file_offset = ROUND_UP(sinfo.file_offset, MiB);
1569             vhdx_update_bat_table_entry(bs, s, &sinfo, &unused, &unused,
1570                                         block_state);
1571             cpu_to_le64s(&s->bat[sinfo.bat_idx]);
1572             sector_num += s->sectors_per_block;
1573         }
1574         ret = bdrv_pwrite(bs, rt_bat->file_offset, s->bat, rt_bat->length);
1575         if (ret < 0) {
1576             goto exit;
1577         }
1578     }
1579 
1580 
1581 
1582 exit:
1583     g_free(s->bat);
1584     return ret;
1585 }
1586 
1587 /* Creates the region table header, and region table entries.
1588  * There are 2 supported region table entries: BAT, and Metadata/
1589  *
1590  * As the calculations for the BAT region table are also needed
1591  * to create the BAT itself, we will also cause the BAT to be
1592  * created.
1593  */
1594 static int vhdx_create_new_region_table(BlockDriverState *bs,
1595                                         uint64_t image_size,
1596                                         uint32_t block_size,
1597                                         uint32_t sector_size,
1598                                         uint32_t log_size,
1599                                         bool use_zero_blocks,
1600                                         VHDXImageType type,
1601                                         uint64_t *metadata_offset)
1602 {
1603     int ret = 0;
1604     uint32_t offset = 0;
1605     void *buffer = NULL;
1606     BDRVVHDXState *s = NULL;
1607     VHDXRegionTableHeader *region_table;
1608     VHDXRegionTableEntry *rt_bat;
1609     VHDXRegionTableEntry *rt_metadata;
1610 
1611     assert(metadata_offset != NULL);
1612 
1613     /* Populate enough of the BDRVVHDXState to be able to use the
1614      * pre-existing BAT calculation, translation, and update functions */
1615     s = g_malloc0(sizeof(BDRVVHDXState));
1616 
1617     s->chunk_ratio = (VHDX_MAX_SECTORS_PER_BLOCK) *
1618                      (uint64_t) sector_size / (uint64_t) block_size;
1619 
1620     s->sectors_per_block = block_size / sector_size;
1621     s->virtual_disk_size = image_size;
1622     s->block_size = block_size;
1623     s->logical_sector_size = sector_size;
1624 
1625     vhdx_set_shift_bits(s);
1626 
1627     vhdx_calc_bat_entries(s);
1628 
1629     /* At this point the VHDX state is populated enough for creation */
1630 
1631     /* a single buffer is used so we can calculate the checksum over the
1632      * entire 64KB block */
1633     buffer = g_malloc0(VHDX_HEADER_BLOCK_SIZE);
1634     region_table = buffer;
1635     offset += sizeof(VHDXRegionTableHeader);
1636     rt_bat = buffer + offset;
1637     offset += sizeof(VHDXRegionTableEntry);
1638     rt_metadata  = buffer + offset;
1639 
1640     region_table->signature = VHDX_REGION_SIGNATURE;
1641     region_table->entry_count = 2;   /* BAT and Metadata */
1642 
1643     rt_bat->guid        = bat_guid;
1644     rt_bat->length      = ROUND_UP(s->bat_entries * sizeof(VHDXBatEntry), MiB);
1645     rt_bat->file_offset = ROUND_UP(VHDX_HEADER_SECTION_END + log_size, MiB);
1646     s->bat_offset = rt_bat->file_offset;
1647 
1648     rt_metadata->guid        = metadata_guid;
1649     rt_metadata->file_offset = ROUND_UP(rt_bat->file_offset + rt_bat->length,
1650                                         MiB);
1651     rt_metadata->length      = 1 * MiB; /* min size, and more than enough */
1652     *metadata_offset = rt_metadata->file_offset;
1653 
1654     vhdx_update_checksum(buffer, VHDX_HEADER_BLOCK_SIZE,
1655                          offsetof(VHDXRegionTableHeader, checksum));
1656 
1657 
1658     /* The region table gives us the data we need to create the BAT,
1659      * so do that now */
1660     ret = vhdx_create_bat(bs, s, image_size, type, use_zero_blocks, rt_bat);
1661 
1662     /* Now write out the region headers to disk */
1663     vhdx_region_header_le_export(region_table);
1664     vhdx_region_entry_le_export(rt_bat);
1665     vhdx_region_entry_le_export(rt_metadata);
1666 
1667     ret = bdrv_pwrite(bs, VHDX_REGION_TABLE_OFFSET, buffer,
1668                       VHDX_HEADER_BLOCK_SIZE);
1669     if (ret < 0) {
1670         goto exit;
1671     }
1672 
1673     ret = bdrv_pwrite(bs, VHDX_REGION_TABLE2_OFFSET, buffer,
1674                       VHDX_HEADER_BLOCK_SIZE);
1675     if (ret < 0) {
1676         goto exit;
1677     }
1678 
1679 
1680 exit:
1681     g_free(s);
1682     g_free(buffer);
1683     return ret;
1684 }
1685 
1686 /* We need to create the following elements:
1687  *
1688  *    .-----------------------------------------------------------------.
1689  *    |   (A)    |   (B)    |    (C)    |     (D)       |     (E)       |
1690  *    |  File ID |  Header1 |  Header 2 |  Region Tbl 1 |  Region Tbl 2 |
1691  *    |          |          |           |               |               |
1692  *    .-----------------------------------------------------------------.
1693  *    0         64KB      128KB       192KB           256KB           320KB
1694  *
1695  *
1696  *    .---- ~ ----------- ~ ------------ ~ ---------------- ~ -----------.
1697  *    |     (F)     |     (G)       |    (H)    |                        |
1698  *    | Journal Log |  BAT / Bitmap |  Metadata |  .... data ......      |
1699  *    |             |               |           |                        |
1700  *    .---- ~ ----------- ~ ------------ ~ ---------------- ~ -----------.
1701  *   1MB
1702  */
1703 static int vhdx_create(const char *filename, QEMUOptionParameter *options,
1704                        Error **errp)
1705 {
1706     int ret = 0;
1707     uint64_t image_size = (uint64_t) 2 * GiB;
1708     uint32_t log_size   = 1 * MiB;
1709     uint32_t block_size = 0;
1710     uint64_t signature;
1711     uint64_t metadata_offset;
1712     bool use_zero_blocks = false;
1713 
1714     gunichar2 *creator = NULL;
1715     glong creator_items;
1716     BlockDriverState *bs;
1717     const char *type = NULL;
1718     VHDXImageType image_type;
1719     Error *local_err = NULL;
1720 
1721     while (options && options->name) {
1722         if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
1723             image_size = options->value.n;
1724         } else if (!strcmp(options->name, VHDX_BLOCK_OPT_LOG_SIZE)) {
1725             log_size = options->value.n;
1726         } else if (!strcmp(options->name, VHDX_BLOCK_OPT_BLOCK_SIZE)) {
1727             block_size = options->value.n;
1728         } else if (!strcmp(options->name, BLOCK_OPT_SUBFMT)) {
1729             type = options->value.s;
1730         } else if (!strcmp(options->name, VHDX_BLOCK_OPT_ZERO)) {
1731             use_zero_blocks = options->value.n != 0;
1732         }
1733         options++;
1734     }
1735 
1736     if (image_size > VHDX_MAX_IMAGE_SIZE) {
1737         error_setg_errno(errp, EINVAL, "Image size too large; max of 64TB");
1738         ret = -EINVAL;
1739         goto exit;
1740     }
1741 
1742     if (type == NULL) {
1743         type = "dynamic";
1744     }
1745 
1746     if (!strcmp(type, "dynamic")) {
1747         image_type = VHDX_TYPE_DYNAMIC;
1748     } else if (!strcmp(type, "fixed")) {
1749         image_type = VHDX_TYPE_FIXED;
1750     } else if (!strcmp(type, "differencing")) {
1751         error_setg_errno(errp, ENOTSUP,
1752                          "Differencing files not yet supported");
1753         ret = -ENOTSUP;
1754         goto exit;
1755     } else {
1756         ret = -EINVAL;
1757         goto exit;
1758     }
1759 
1760     /* These are pretty arbitrary, and mainly designed to keep the BAT
1761      * size reasonable to load into RAM */
1762     if (block_size == 0) {
1763         if (image_size > 32 * TiB) {
1764             block_size = 64 * MiB;
1765         } else if (image_size > (uint64_t) 100 * GiB) {
1766             block_size = 32 * MiB;
1767         } else if (image_size > 1 * GiB) {
1768             block_size = 16 * MiB;
1769         } else {
1770             block_size = 8 * MiB;
1771         }
1772     }
1773 
1774 
1775     /* make the log size close to what was specified, but must be
1776      * min 1MB, and multiple of 1MB */
1777     log_size = ROUND_UP(log_size, MiB);
1778 
1779     block_size = ROUND_UP(block_size, MiB);
1780     block_size = block_size > VHDX_BLOCK_SIZE_MAX ? VHDX_BLOCK_SIZE_MAX :
1781                                                     block_size;
1782 
1783     ret = bdrv_create_file(filename, options, &local_err);
1784     if (ret < 0) {
1785         error_propagate(errp, local_err);
1786         goto exit;
1787     }
1788 
1789     ret = bdrv_file_open(&bs, filename, NULL, BDRV_O_RDWR, &local_err);
1790     if (ret < 0) {
1791         error_propagate(errp, local_err);
1792         goto exit;
1793     }
1794 
1795     /* Create (A) */
1796 
1797     /* The creator field is optional, but may be useful for
1798      * debugging / diagnostics */
1799     creator = g_utf8_to_utf16("QEMU v" QEMU_VERSION, -1, NULL,
1800                               &creator_items, NULL);
1801     signature = cpu_to_le64(VHDX_FILE_SIGNATURE);
1802     bdrv_pwrite(bs, VHDX_FILE_ID_OFFSET, &signature, sizeof(signature));
1803     if (ret < 0) {
1804         goto delete_and_exit;
1805     }
1806     if (creator) {
1807         bdrv_pwrite(bs, VHDX_FILE_ID_OFFSET + sizeof(signature), creator,
1808                     creator_items * sizeof(gunichar2));
1809         if (ret < 0) {
1810             goto delete_and_exit;
1811         }
1812     }
1813 
1814 
1815     /* Creates (B),(C) */
1816     ret = vhdx_create_new_headers(bs, image_size, log_size);
1817     if (ret < 0) {
1818         goto delete_and_exit;
1819     }
1820 
1821     /* Creates (D),(E),(G) explicitly. (F) created as by-product */
1822     ret = vhdx_create_new_region_table(bs, image_size, block_size, 512,
1823                                        log_size, use_zero_blocks, image_type,
1824                                        &metadata_offset);
1825     if (ret < 0) {
1826         goto delete_and_exit;
1827     }
1828 
1829     /* Creates (H) */
1830     ret = vhdx_create_new_metadata(bs, image_size, block_size, 512,
1831                                    metadata_offset, image_type);
1832     if (ret < 0) {
1833         goto delete_and_exit;
1834     }
1835 
1836 
1837 
1838 delete_and_exit:
1839     bdrv_unref(bs);
1840 exit:
1841     g_free(creator);
1842     return ret;
1843 }
1844 
1845 static QEMUOptionParameter vhdx_create_options[] = {
1846     {
1847         .name = BLOCK_OPT_SIZE,
1848         .type = OPT_SIZE,
1849         .help = "Virtual disk size; max of 64TB."
1850     },
1851     {
1852         .name = VHDX_BLOCK_OPT_LOG_SIZE,
1853         .type = OPT_SIZE,
1854         .value.n = 1 * MiB,
1855         .help = "Log size; min 1MB."
1856     },
1857     {
1858         .name = VHDX_BLOCK_OPT_BLOCK_SIZE,
1859         .type = OPT_SIZE,
1860         .value.n = 0,
1861         .help = "Block Size; min 1MB, max 256MB. " \
1862                 "0 means auto-calculate based on image size."
1863     },
1864     {
1865         .name = BLOCK_OPT_SUBFMT,
1866         .type = OPT_STRING,
1867         .help = "VHDX format type, can be either 'dynamic' or 'fixed'. "\
1868                 "Default is 'dynamic'."
1869     },
1870     {
1871         .name = VHDX_BLOCK_OPT_ZERO,
1872         .type = OPT_FLAG,
1873         .help = "Force use of payload blocks of type 'ZERO'.  Non-standard."
1874     },
1875     { NULL }
1876 };
1877 
1878 static BlockDriver bdrv_vhdx = {
1879     .format_name            = "vhdx",
1880     .instance_size          = sizeof(BDRVVHDXState),
1881     .bdrv_probe             = vhdx_probe,
1882     .bdrv_open              = vhdx_open,
1883     .bdrv_close             = vhdx_close,
1884     .bdrv_reopen_prepare    = vhdx_reopen_prepare,
1885     .bdrv_co_readv          = vhdx_co_readv,
1886     .bdrv_co_writev         = vhdx_co_writev,
1887     .bdrv_create            = vhdx_create,
1888 
1889     .create_options         = vhdx_create_options,
1890 };
1891 
1892 static void bdrv_vhdx_init(void)
1893 {
1894     bdrv_register(&bdrv_vhdx);
1895 }
1896 
1897 block_init(bdrv_vhdx_init);
1898