1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
|
/*
* Copyright (c) 2019 Nutanix Inc. All rights reserved.
*
* Authors: Mike Cui <cui@nutanix.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of Nutanix nor the names of its contributors may be
* used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <stdio.h>
#include <sys/param.h>
#include <stddef.h>
#include <stdbool.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include "dma.h"
#include "private.h"
static inline ssize_t
fd_get_blocksize(int fd)
{
struct stat st;
if (fstat(fd, &st) != 0)
return -1;
return st.st_blksize;
}
/* Returns true if 2 fds refer to the same file.
If any fd is invalid, return false. */
static inline bool
fds_are_same_file(int fd1, int fd2)
{
struct stat st1, st2;
if (fd1 == fd2) {
return true;
}
return (fstat(fd1, &st1) == 0 && fstat(fd2, &st2) == 0 &&
st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino);
}
dma_controller_t *
dma_controller_create(vfu_ctx_t *vfu_ctx, int max_regions)
{
dma_controller_t *dma;
dma = malloc(offsetof(dma_controller_t, regions) +
max_regions * sizeof(dma->regions[0]));
if (dma == NULL) {
return dma;
}
dma->vfu_ctx = vfu_ctx;
dma->max_regions = max_regions;
dma->nregions = 0;
memset(dma->regions, 0, max_regions * sizeof(dma->regions[0]));
dma->dirty_pgsize = 0;
return dma;
}
void
MOCK_DEFINE(dma_controller_unmap_region)(dma_controller_t *dma,
dma_memory_region_t *region)
{
int err;
assert(dma != NULL);
assert(region != NULL);
err = munmap(region->info.mapping.iov_base, region->info.mapping.iov_len);
if (err != 0) {
vfu_log(dma->vfu_ctx, LOG_DEBUG, "failed to unmap fd=%d "
"mapping=[%p, %p): %m",
region->fd, region->info.mapping.iov_base,
iov_end(®ion->info.mapping));
}
assert(region->fd != -1);
if (close(region->fd) == -1) {
vfu_log(dma->vfu_ctx, LOG_WARNING, "failed to close fd %d: %m",
region->fd);
}
}
static void
array_remove(void *array, size_t elem_size, size_t index, int *nr_elemsp)
{
void *dest;
void *src;
size_t nr;
assert((size_t)*nr_elemsp > index);
nr = *nr_elemsp - (index + 1);
dest = (char *)array + (index * elem_size);
src = (char *)array + ((index + 1) * elem_size);
memmove(dest, src, nr * elem_size);
(*nr_elemsp)--;
}
/* FIXME not thread safe */
int
MOCK_DEFINE(dma_controller_remove_region)(dma_controller_t *dma,
vfu_dma_addr_t dma_addr, size_t size,
vfu_dma_unregister_cb_t *dma_unregister,
void *data)
{
int idx;
dma_memory_region_t *region;
int err;
assert(dma != NULL);
for (idx = 0; idx < dma->nregions; idx++) {
region = &dma->regions[idx];
if (region->info.iova.iov_base != dma_addr ||
region->info.iova.iov_len != size) {
continue;
}
err = dma_unregister(data, ®ion->info);
if (err != 0) {
vfu_log(dma->vfu_ctx, LOG_ERR,
"failed to dma_unregister() DMA region [%p, %p): %s",
region->info.iova.iov_base, iov_end(®ion->info.iova),
strerror(err));
return -err;
}
assert(region->refcnt == 0);
if (region->info.vaddr != NULL) {
dma_controller_unmap_region(dma, region);
} else {
assert(region->fd == -1);
}
array_remove(&dma->regions, sizeof (*region), idx, &dma->nregions);
return 0;
}
return -ENOENT;
}
void
dma_controller_remove_regions(dma_controller_t *dma)
{
int i;
assert(dma != NULL);
for (i = 0; i < dma->nregions; i++) {
dma_memory_region_t *region = &dma->regions[i];
vfu_log(dma->vfu_ctx, LOG_DEBUG, "removing DMA region "
"iova=[%p, %p) vaddr=%p mapping=[%p, %p)",
region->info.iova.iov_base, iov_end(®ion->info.iova),
region->info.vaddr,
region->info.mapping.iov_base, iov_end(®ion->info.mapping));
if (region->info.vaddr != NULL) {
dma_controller_unmap_region(dma, region);
} else {
assert(region->fd == -1);
}
}
memset(dma->regions, 0, dma->max_regions * sizeof(dma->regions[0]));
dma->nregions = 0;
}
void
dma_controller_destroy(dma_controller_t *dma)
{
if (dma == NULL) {
return;
}
dma_controller_remove_regions(dma);
free(dma);
}
static int
dma_map_region(dma_controller_t *dma, dma_memory_region_t *region)
{
void *mmap_base;
size_t mmap_len;
off_t offset;
offset = ROUND_DOWN(region->offset, region->info.page_size);
mmap_len = ROUND_UP(region->info.iova.iov_len, region->info.page_size);
mmap_base = mmap(NULL, mmap_len, region->info.prot, MAP_SHARED,
region->fd, offset);
if (mmap_base == MAP_FAILED) {
return -errno;
}
// Do not dump.
madvise(mmap_base, mmap_len, MADV_DONTDUMP);
region->info.mapping.iov_base = mmap_base;
region->info.mapping.iov_len = mmap_len;
region->info.vaddr = mmap_base + (region->offset - offset);
vfu_log(dma->vfu_ctx, LOG_DEBUG, "mapped DMA region iova=[%p, %p) "
"vaddr=%p page_size=%#lx mapping=[%p, %p)",
region->info.iova.iov_base, iov_end(®ion->info.iova),
region->info.vaddr, region->info.page_size,
region->info.mapping.iov_base, iov_end(®ion->info.mapping));
return 0;
}
int
MOCK_DEFINE(dma_controller_add_region)(dma_controller_t *dma,
vfu_dma_addr_t dma_addr, size_t size,
int fd, off_t offset, uint32_t prot)
{
dma_memory_region_t *region;
int page_size = 0;
char rstr[1024];
int idx;
int ret;
assert(dma != NULL);
snprintf(rstr, sizeof(rstr), "[%p, %p) fd=%d offset=%#lx prot=%#x",
dma_addr, (char *)dma_addr + size, fd, offset, prot);
for (idx = 0; idx < dma->nregions; idx++) {
region = &dma->regions[idx];
/* First check if this is the same exact region. */
if (region->info.iova.iov_base == dma_addr &&
region->info.iova.iov_len == size) {
if (offset != region->offset) {
vfu_log(dma->vfu_ctx, LOG_ERR, "bad offset for new DMA region "
"%s; existing=%#lx", rstr, region->offset);
ret = -EINVAL;
goto out;
}
if (!fds_are_same_file(region->fd, fd)) {
/*
* Printing the file descriptors here doesn't really make
* sense as they can be different but actually pointing to
* the same file, however in the majority of cases we'll be
* using a single fd.
*/
vfu_log(dma->vfu_ctx, LOG_ERR, "bad fd for new DMA region %s; "
"existing=%d", rstr, region->fd);
ret = -EINVAL;
goto out;
}
if (region->info.prot != prot) {
vfu_log(dma->vfu_ctx, LOG_ERR, "bad prot for new DMA region "
"%s; existing=%#x", rstr, region->info.prot);
ret = -EINVAL;
goto out;
}
return idx;
}
/* Check for overlap, i.e. start of one region is within another. */
if ((dma_addr >= region->info.iova.iov_base &&
dma_addr < iov_end(®ion->info.iova)) ||
(region->info.iova.iov_base >= dma_addr &&
region->info.iova.iov_base < dma_addr + size)) {
vfu_log(dma->vfu_ctx, LOG_INFO, "new DMA region %s overlaps with "
"DMA region [%p, %p)", rstr, region->info.iova.iov_base,
iov_end(®ion->info.iova));
ret = -EINVAL;
goto out;
}
}
if (dma->nregions == dma->max_regions) {
vfu_log(dma->vfu_ctx, LOG_ERR, "hit max regions %d", dma->max_regions);
ret = -EINVAL;
goto out;
}
idx = dma->nregions;
region = &dma->regions[idx];
if (fd != -1) {
page_size = fd_get_blocksize(fd);
if (page_size < 0) {
vfu_log(dma->vfu_ctx, LOG_ERR, "bad page size %d", page_size);
ret = -EINVAL;
goto out;
}
}
page_size = MAX(page_size, getpagesize());
memset(region, 0, sizeof (*region));
region->info.iova.iov_base = (void *)dma_addr;
region->info.iova.iov_len = size;
region->info.page_size = page_size;
region->info.prot = prot;
region->offset = offset;
region->fd = fd;
if (fd != -1) {
ret = dma_map_region(dma, region);
if (ret != 0) {
vfu_log(dma->vfu_ctx, LOG_ERR,
"failed to memory map DMA region %s: %s", rstr,
strerror(-ret));
if (close(region->fd) == -1) {
vfu_log(dma->vfu_ctx, LOG_WARNING,
"failed to close fd %d: %m", region->fd);
}
goto out;
}
}
ret = idx;
dma->nregions++;
out:
return ret;
}
int
_dma_addr_sg_split(const dma_controller_t *dma,
vfu_dma_addr_t dma_addr, uint32_t len,
dma_sg_t *sg, int max_sg, int prot)
{
int idx;
int cnt = 0, ret;
bool found = true; // Whether the current region is found.
while (found && len > 0) {
found = false;
for (idx = 0; idx < dma->nregions; idx++) {
const dma_memory_region_t *const region = &dma->regions[idx];
vfu_dma_addr_t region_start = region->info.iova.iov_base;
vfu_dma_addr_t region_end = iov_end(®ion->info.iova);
while (dma_addr >= region_start && dma_addr < region_end) {
size_t region_len = MIN(region_end - dma_addr, len);
if (cnt < max_sg) {
ret = dma_init_sg(dma, sg, dma_addr, region_len, prot, idx);
if (ret < 0) {
return ret;
}
}
cnt++;
// dma_addr found, may need to start from the top for the
// next dma_addr.
found = true;
dma_addr += region_len;
len -= region_len;
if (len == 0) {
goto out;
}
}
}
}
out:
if (!found) {
// There is still a region which was not found.
assert(len > 0);
errno = ENOENT;
return -1;
} else if (cnt > max_sg) {
cnt = -cnt - 1;
}
errno = 0;
return cnt;
}
static ssize_t
get_bitmap_size(size_t region_size, size_t pgsize)
{
if (pgsize == 0) {
return -EINVAL;
}
if (region_size < pgsize) {
return -EINVAL;
}
size_t nr_pages = (region_size / pgsize) + (region_size % pgsize != 0);
return (nr_pages / CHAR_BIT) + (nr_pages % CHAR_BIT != 0);
}
int dma_controller_dirty_page_logging_start(dma_controller_t *dma, size_t pgsize)
{
int i;
assert(dma != NULL);
if (pgsize == 0) {
return -EINVAL;
}
if (dma->dirty_pgsize > 0) {
if (dma->dirty_pgsize != pgsize) {
return -EINVAL;
}
return 0;
}
for (i = 0; i < dma->nregions; i++) {
dma_memory_region_t *region = &dma->regions[i];
ssize_t bitmap_size;
bitmap_size = get_bitmap_size(region->info.iova.iov_len, pgsize);
if (bitmap_size < 0) {
return bitmap_size;
}
region->dirty_bitmap = calloc(bitmap_size, sizeof(char));
if (region->dirty_bitmap == NULL) {
int j, ret = -errno;
for (j = 0; j < i; j++) {
region = &dma->regions[j];
free(region->dirty_bitmap);
region->dirty_bitmap = NULL;
}
return ret;
}
}
dma->dirty_pgsize = pgsize;
return 0;
}
int dma_controller_dirty_page_logging_stop(dma_controller_t *dma)
{
int i;
assert(dma != NULL);
if (dma->dirty_pgsize == 0) {
return 0;
}
for (i = 0; i < dma->nregions; i++) {
free(dma->regions[i].dirty_bitmap);
dma->regions[i].dirty_bitmap = NULL;
}
dma->dirty_pgsize = 0;
return 0;
}
int
dma_controller_dirty_page_get(dma_controller_t *dma, vfu_dma_addr_t addr,
int len, size_t pgsize, size_t size, char **data)
{
int ret;
ssize_t bitmap_size;
dma_sg_t sg;
dma_memory_region_t *region;
assert(dma != NULL);
assert(data != NULL);
/*
* FIXME for now we support IOVAs that match exactly the DMA region. This
* is purely for simplifying the implementation. We MUST allow arbitrary
* IOVAs.
*/
ret = dma_addr_to_sg(dma, addr, len, &sg, 1, PROT_NONE);
if (ret != 1 || sg.dma_addr != addr || sg.length != len) {
return -ENOTSUP;
}
if (pgsize != dma->dirty_pgsize) {
return -EINVAL;
}
bitmap_size = get_bitmap_size(len, pgsize);
if (bitmap_size < 0) {
return bitmap_size;
}
/*
* FIXME they must be equal because this is how much data the client
* expects to receive.
*/
if (size != (size_t)bitmap_size) {
return -EINVAL;
}
region = &dma->regions[sg.region];
*data = region->dirty_bitmap;
return 0;
}
/* ex: set tabstop=4 shiftwidth=4 softtabstop=4 expandtab: */
|