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UBUNTU: Ubuntu-5.15.0-39.42
[mirror_ubuntu-jammy-kernel.git] / drivers / xen / gntdev.c
1 /******************************************************************************
2 * gntdev.c
3 *
4 * Device for accessing (in user-space) pages that have been granted by other
5 * domains.
6 *
7 * Copyright (c) 2006-2007, D G Murray.
8 * (c) 2009 Gerd Hoffmann <kraxel@redhat.com>
9 * (c) 2018 Oleksandr Andrushchenko, EPAM Systems Inc.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 */
20
21 #undef DEBUG
22
23 #define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
24
25 #include <linux/dma-mapping.h>
26 #include <linux/module.h>
27 #include <linux/kernel.h>
28 #include <linux/init.h>
29 #include <linux/miscdevice.h>
30 #include <linux/fs.h>
31 #include <linux/uaccess.h>
32 #include <linux/sched.h>
33 #include <linux/sched/mm.h>
34 #include <linux/spinlock.h>
35 #include <linux/slab.h>
36 #include <linux/highmem.h>
37 #include <linux/refcount.h>
38
39 #include <xen/xen.h>
40 #include <xen/grant_table.h>
41 #include <xen/balloon.h>
42 #include <xen/gntdev.h>
43 #include <xen/events.h>
44 #include <xen/page.h>
45 #include <asm/xen/hypervisor.h>
46 #include <asm/xen/hypercall.h>
47
48 #include "gntdev-common.h"
49 #ifdef CONFIG_XEN_GNTDEV_DMABUF
50 #include "gntdev-dmabuf.h"
51 #endif
52
53 MODULE_LICENSE("GPL");
54 MODULE_AUTHOR("Derek G. Murray <Derek.Murray@cl.cam.ac.uk>, "
55 "Gerd Hoffmann <kraxel@redhat.com>");
56 MODULE_DESCRIPTION("User-space granted page access driver");
57
58 static unsigned int limit = 64*1024;
59 module_param(limit, uint, 0644);
60 MODULE_PARM_DESC(limit,
61 "Maximum number of grants that may be mapped by one mapping request");
62
63 static int use_ptemod;
64
65 static int unmap_grant_pages(struct gntdev_grant_map *map,
66 int offset, int pages);
67
68 static struct miscdevice gntdev_miscdev;
69
70 /* ------------------------------------------------------------------ */
71
72 bool gntdev_test_page_count(unsigned int count)
73 {
74 return !count || count > limit;
75 }
76
77 static void gntdev_print_maps(struct gntdev_priv *priv,
78 char *text, int text_index)
79 {
80 #ifdef DEBUG
81 struct gntdev_grant_map *map;
82
83 pr_debug("%s: maps list (priv %p)\n", __func__, priv);
84 list_for_each_entry(map, &priv->maps, next)
85 pr_debug(" index %2d, count %2d %s\n",
86 map->index, map->count,
87 map->index == text_index && text ? text : "");
88 #endif
89 }
90
91 static void gntdev_free_map(struct gntdev_grant_map *map)
92 {
93 if (map == NULL)
94 return;
95
96 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC
97 if (map->dma_vaddr) {
98 struct gnttab_dma_alloc_args args;
99
100 args.dev = map->dma_dev;
101 args.coherent = !!(map->dma_flags & GNTDEV_DMA_FLAG_COHERENT);
102 args.nr_pages = map->count;
103 args.pages = map->pages;
104 args.frames = map->frames;
105 args.vaddr = map->dma_vaddr;
106 args.dev_bus_addr = map->dma_bus_addr;
107
108 gnttab_dma_free_pages(&args);
109 } else
110 #endif
111 if (map->pages)
112 gnttab_free_pages(map->count, map->pages);
113
114 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC
115 kvfree(map->frames);
116 #endif
117 kvfree(map->pages);
118 kvfree(map->grants);
119 kvfree(map->map_ops);
120 kvfree(map->unmap_ops);
121 kvfree(map->kmap_ops);
122 kvfree(map->kunmap_ops);
123 kfree(map);
124 }
125
126 struct gntdev_grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count,
127 int dma_flags)
128 {
129 struct gntdev_grant_map *add;
130 int i;
131
132 add = kzalloc(sizeof(*add), GFP_KERNEL);
133 if (NULL == add)
134 return NULL;
135
136 add->grants = kvmalloc_array(count, sizeof(add->grants[0]),
137 GFP_KERNEL);
138 add->map_ops = kvmalloc_array(count, sizeof(add->map_ops[0]),
139 GFP_KERNEL);
140 add->unmap_ops = kvmalloc_array(count, sizeof(add->unmap_ops[0]),
141 GFP_KERNEL);
142 add->pages = kvcalloc(count, sizeof(add->pages[0]), GFP_KERNEL);
143 if (NULL == add->grants ||
144 NULL == add->map_ops ||
145 NULL == add->unmap_ops ||
146 NULL == add->pages)
147 goto err;
148 if (use_ptemod) {
149 add->kmap_ops = kvmalloc_array(count, sizeof(add->kmap_ops[0]),
150 GFP_KERNEL);
151 add->kunmap_ops = kvmalloc_array(count, sizeof(add->kunmap_ops[0]),
152 GFP_KERNEL);
153 if (NULL == add->kmap_ops || NULL == add->kunmap_ops)
154 goto err;
155 }
156
157 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC
158 add->dma_flags = dma_flags;
159
160 /*
161 * Check if this mapping is requested to be backed
162 * by a DMA buffer.
163 */
164 if (dma_flags & (GNTDEV_DMA_FLAG_WC | GNTDEV_DMA_FLAG_COHERENT)) {
165 struct gnttab_dma_alloc_args args;
166
167 add->frames = kvcalloc(count, sizeof(add->frames[0]),
168 GFP_KERNEL);
169 if (!add->frames)
170 goto err;
171
172 /* Remember the device, so we can free DMA memory. */
173 add->dma_dev = priv->dma_dev;
174
175 args.dev = priv->dma_dev;
176 args.coherent = !!(dma_flags & GNTDEV_DMA_FLAG_COHERENT);
177 args.nr_pages = count;
178 args.pages = add->pages;
179 args.frames = add->frames;
180
181 if (gnttab_dma_alloc_pages(&args))
182 goto err;
183
184 add->dma_vaddr = args.vaddr;
185 add->dma_bus_addr = args.dev_bus_addr;
186 } else
187 #endif
188 if (gnttab_alloc_pages(count, add->pages))
189 goto err;
190
191 for (i = 0; i < count; i++) {
192 add->grants[i].domid = DOMID_INVALID;
193 add->grants[i].ref = INVALID_GRANT_REF;
194 add->map_ops[i].handle = INVALID_GRANT_HANDLE;
195 add->unmap_ops[i].handle = INVALID_GRANT_HANDLE;
196 if (use_ptemod) {
197 add->kmap_ops[i].handle = INVALID_GRANT_HANDLE;
198 add->kunmap_ops[i].handle = INVALID_GRANT_HANDLE;
199 }
200 }
201
202 add->index = 0;
203 add->count = count;
204 refcount_set(&add->users, 1);
205
206 return add;
207
208 err:
209 gntdev_free_map(add);
210 return NULL;
211 }
212
213 void gntdev_add_map(struct gntdev_priv *priv, struct gntdev_grant_map *add)
214 {
215 struct gntdev_grant_map *map;
216
217 list_for_each_entry(map, &priv->maps, next) {
218 if (add->index + add->count < map->index) {
219 list_add_tail(&add->next, &map->next);
220 goto done;
221 }
222 add->index = map->index + map->count;
223 }
224 list_add_tail(&add->next, &priv->maps);
225
226 done:
227 gntdev_print_maps(priv, "[new]", add->index);
228 }
229
230 static struct gntdev_grant_map *gntdev_find_map_index(struct gntdev_priv *priv,
231 int index, int count)
232 {
233 struct gntdev_grant_map *map;
234
235 list_for_each_entry(map, &priv->maps, next) {
236 if (map->index != index)
237 continue;
238 if (count && map->count != count)
239 continue;
240 return map;
241 }
242 return NULL;
243 }
244
245 void gntdev_put_map(struct gntdev_priv *priv, struct gntdev_grant_map *map)
246 {
247 if (!map)
248 return;
249
250 if (!refcount_dec_and_test(&map->users))
251 return;
252
253 if (map->pages && !use_ptemod)
254 unmap_grant_pages(map, 0, map->count);
255
256 if (map->notify.flags & UNMAP_NOTIFY_SEND_EVENT) {
257 notify_remote_via_evtchn(map->notify.event);
258 evtchn_put(map->notify.event);
259 }
260 gntdev_free_map(map);
261 }
262
263 /* ------------------------------------------------------------------ */
264
265 static int find_grant_ptes(pte_t *pte, unsigned long addr, void *data)
266 {
267 struct gntdev_grant_map *map = data;
268 unsigned int pgnr = (addr - map->vma->vm_start) >> PAGE_SHIFT;
269 int flags = map->flags | GNTMAP_application_map | GNTMAP_contains_pte |
270 (1 << _GNTMAP_guest_avail0);
271 u64 pte_maddr;
272
273 BUG_ON(pgnr >= map->count);
274 pte_maddr = arbitrary_virt_to_machine(pte).maddr;
275
276 gnttab_set_map_op(&map->map_ops[pgnr], pte_maddr, flags,
277 map->grants[pgnr].ref,
278 map->grants[pgnr].domid);
279 gnttab_set_unmap_op(&map->unmap_ops[pgnr], pte_maddr, flags,
280 INVALID_GRANT_HANDLE);
281 return 0;
282 }
283
284 int gntdev_map_grant_pages(struct gntdev_grant_map *map)
285 {
286 int i, err = 0;
287
288 if (!use_ptemod) {
289 /* Note: it could already be mapped */
290 if (map->map_ops[0].handle != INVALID_GRANT_HANDLE)
291 return 0;
292 for (i = 0; i < map->count; i++) {
293 unsigned long addr = (unsigned long)
294 pfn_to_kaddr(page_to_pfn(map->pages[i]));
295 gnttab_set_map_op(&map->map_ops[i], addr, map->flags,
296 map->grants[i].ref,
297 map->grants[i].domid);
298 gnttab_set_unmap_op(&map->unmap_ops[i], addr,
299 map->flags, INVALID_GRANT_HANDLE);
300 }
301 } else {
302 /*
303 * Setup the map_ops corresponding to the pte entries pointing
304 * to the kernel linear addresses of the struct pages.
305 * These ptes are completely different from the user ptes dealt
306 * with find_grant_ptes.
307 * Note that GNTMAP_device_map isn't needed here: The
308 * dev_bus_addr output field gets consumed only from ->map_ops,
309 * and by not requesting it when mapping we also avoid needing
310 * to mirror dev_bus_addr into ->unmap_ops (and holding an extra
311 * reference to the page in the hypervisor).
312 */
313 unsigned int flags = (map->flags & ~GNTMAP_device_map) |
314 GNTMAP_host_map;
315
316 for (i = 0; i < map->count; i++) {
317 unsigned long address = (unsigned long)
318 pfn_to_kaddr(page_to_pfn(map->pages[i]));
319 BUG_ON(PageHighMem(map->pages[i]));
320
321 gnttab_set_map_op(&map->kmap_ops[i], address, flags,
322 map->grants[i].ref,
323 map->grants[i].domid);
324 gnttab_set_unmap_op(&map->kunmap_ops[i], address,
325 flags, INVALID_GRANT_HANDLE);
326 }
327 }
328
329 pr_debug("map %d+%d\n", map->index, map->count);
330 err = gnttab_map_refs(map->map_ops, map->kmap_ops, map->pages,
331 map->count);
332
333 for (i = 0; i < map->count; i++) {
334 if (map->map_ops[i].status == GNTST_okay)
335 map->unmap_ops[i].handle = map->map_ops[i].handle;
336 else if (!err)
337 err = -EINVAL;
338
339 if (map->flags & GNTMAP_device_map)
340 map->unmap_ops[i].dev_bus_addr = map->map_ops[i].dev_bus_addr;
341
342 if (use_ptemod) {
343 if (map->kmap_ops[i].status == GNTST_okay)
344 map->kunmap_ops[i].handle = map->kmap_ops[i].handle;
345 else if (!err)
346 err = -EINVAL;
347 }
348 }
349 return err;
350 }
351
352 static int __unmap_grant_pages(struct gntdev_grant_map *map, int offset,
353 int pages)
354 {
355 int i, err = 0;
356 struct gntab_unmap_queue_data unmap_data;
357
358 if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) {
359 int pgno = (map->notify.addr >> PAGE_SHIFT);
360 if (pgno >= offset && pgno < offset + pages) {
361 /* No need for kmap, pages are in lowmem */
362 uint8_t *tmp = pfn_to_kaddr(page_to_pfn(map->pages[pgno]));
363 tmp[map->notify.addr & (PAGE_SIZE-1)] = 0;
364 map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE;
365 }
366 }
367
368 unmap_data.unmap_ops = map->unmap_ops + offset;
369 unmap_data.kunmap_ops = use_ptemod ? map->kunmap_ops + offset : NULL;
370 unmap_data.pages = map->pages + offset;
371 unmap_data.count = pages;
372
373 err = gnttab_unmap_refs_sync(&unmap_data);
374 if (err)
375 return err;
376
377 for (i = 0; i < pages; i++) {
378 if (map->unmap_ops[offset+i].status)
379 err = -EINVAL;
380 pr_debug("unmap handle=%d st=%d\n",
381 map->unmap_ops[offset+i].handle,
382 map->unmap_ops[offset+i].status);
383 map->unmap_ops[offset+i].handle = INVALID_GRANT_HANDLE;
384 if (use_ptemod) {
385 if (map->kunmap_ops[offset+i].status)
386 err = -EINVAL;
387 pr_debug("kunmap handle=%u st=%d\n",
388 map->kunmap_ops[offset+i].handle,
389 map->kunmap_ops[offset+i].status);
390 map->kunmap_ops[offset+i].handle = INVALID_GRANT_HANDLE;
391 }
392 }
393 return err;
394 }
395
396 static int unmap_grant_pages(struct gntdev_grant_map *map, int offset,
397 int pages)
398 {
399 int range, err = 0;
400
401 pr_debug("unmap %d+%d [%d+%d]\n", map->index, map->count, offset, pages);
402
403 /* It is possible the requested range will have a "hole" where we
404 * already unmapped some of the grants. Only unmap valid ranges.
405 */
406 while (pages && !err) {
407 while (pages &&
408 map->unmap_ops[offset].handle == INVALID_GRANT_HANDLE) {
409 offset++;
410 pages--;
411 }
412 range = 0;
413 while (range < pages) {
414 if (map->unmap_ops[offset + range].handle ==
415 INVALID_GRANT_HANDLE)
416 break;
417 range++;
418 }
419 err = __unmap_grant_pages(map, offset, range);
420 offset += range;
421 pages -= range;
422 }
423
424 return err;
425 }
426
427 /* ------------------------------------------------------------------ */
428
429 static void gntdev_vma_open(struct vm_area_struct *vma)
430 {
431 struct gntdev_grant_map *map = vma->vm_private_data;
432
433 pr_debug("gntdev_vma_open %p\n", vma);
434 refcount_inc(&map->users);
435 }
436
437 static void gntdev_vma_close(struct vm_area_struct *vma)
438 {
439 struct gntdev_grant_map *map = vma->vm_private_data;
440 struct file *file = vma->vm_file;
441 struct gntdev_priv *priv = file->private_data;
442
443 pr_debug("gntdev_vma_close %p\n", vma);
444 if (use_ptemod) {
445 WARN_ON(map->vma != vma);
446 mmu_interval_notifier_remove(&map->notifier);
447 map->vma = NULL;
448 }
449 vma->vm_private_data = NULL;
450 gntdev_put_map(priv, map);
451 }
452
453 static struct page *gntdev_vma_find_special_page(struct vm_area_struct *vma,
454 unsigned long addr)
455 {
456 struct gntdev_grant_map *map = vma->vm_private_data;
457
458 return map->pages[(addr - map->pages_vm_start) >> PAGE_SHIFT];
459 }
460
461 static const struct vm_operations_struct gntdev_vmops = {
462 .open = gntdev_vma_open,
463 .close = gntdev_vma_close,
464 .find_special_page = gntdev_vma_find_special_page,
465 };
466
467 /* ------------------------------------------------------------------ */
468
469 static bool gntdev_invalidate(struct mmu_interval_notifier *mn,
470 const struct mmu_notifier_range *range,
471 unsigned long cur_seq)
472 {
473 struct gntdev_grant_map *map =
474 container_of(mn, struct gntdev_grant_map, notifier);
475 unsigned long mstart, mend;
476 int err;
477
478 if (!mmu_notifier_range_blockable(range))
479 return false;
480
481 /*
482 * If the VMA is split or otherwise changed the notifier is not
483 * updated, but we don't want to process VA's outside the modified
484 * VMA. FIXME: It would be much more understandable to just prevent
485 * modifying the VMA in the first place.
486 */
487 if (map->vma->vm_start >= range->end ||
488 map->vma->vm_end <= range->start)
489 return true;
490
491 mstart = max(range->start, map->vma->vm_start);
492 mend = min(range->end, map->vma->vm_end);
493 pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n",
494 map->index, map->count,
495 map->vma->vm_start, map->vma->vm_end,
496 range->start, range->end, mstart, mend);
497 err = unmap_grant_pages(map,
498 (mstart - map->vma->vm_start) >> PAGE_SHIFT,
499 (mend - mstart) >> PAGE_SHIFT);
500 WARN_ON(err);
501
502 return true;
503 }
504
505 static const struct mmu_interval_notifier_ops gntdev_mmu_ops = {
506 .invalidate = gntdev_invalidate,
507 };
508
509 /* ------------------------------------------------------------------ */
510
511 static int gntdev_open(struct inode *inode, struct file *flip)
512 {
513 struct gntdev_priv *priv;
514
515 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
516 if (!priv)
517 return -ENOMEM;
518
519 INIT_LIST_HEAD(&priv->maps);
520 mutex_init(&priv->lock);
521
522 #ifdef CONFIG_XEN_GNTDEV_DMABUF
523 priv->dmabuf_priv = gntdev_dmabuf_init(flip);
524 if (IS_ERR(priv->dmabuf_priv)) {
525 int ret = PTR_ERR(priv->dmabuf_priv);
526
527 kfree(priv);
528 return ret;
529 }
530 #endif
531
532 flip->private_data = priv;
533 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC
534 priv->dma_dev = gntdev_miscdev.this_device;
535 dma_coerce_mask_and_coherent(priv->dma_dev, DMA_BIT_MASK(64));
536 #endif
537 pr_debug("priv %p\n", priv);
538
539 return 0;
540 }
541
542 static int gntdev_release(struct inode *inode, struct file *flip)
543 {
544 struct gntdev_priv *priv = flip->private_data;
545 struct gntdev_grant_map *map;
546
547 pr_debug("priv %p\n", priv);
548
549 mutex_lock(&priv->lock);
550 while (!list_empty(&priv->maps)) {
551 map = list_entry(priv->maps.next,
552 struct gntdev_grant_map, next);
553 list_del(&map->next);
554 gntdev_put_map(NULL /* already removed */, map);
555 }
556 mutex_unlock(&priv->lock);
557
558 #ifdef CONFIG_XEN_GNTDEV_DMABUF
559 gntdev_dmabuf_fini(priv->dmabuf_priv);
560 #endif
561
562 kfree(priv);
563 return 0;
564 }
565
566 static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv,
567 struct ioctl_gntdev_map_grant_ref __user *u)
568 {
569 struct ioctl_gntdev_map_grant_ref op;
570 struct gntdev_grant_map *map;
571 int err;
572
573 if (copy_from_user(&op, u, sizeof(op)) != 0)
574 return -EFAULT;
575 pr_debug("priv %p, add %d\n", priv, op.count);
576 if (unlikely(gntdev_test_page_count(op.count)))
577 return -EINVAL;
578
579 err = -ENOMEM;
580 map = gntdev_alloc_map(priv, op.count, 0 /* This is not a dma-buf. */);
581 if (!map)
582 return err;
583
584 if (copy_from_user(map->grants, &u->refs,
585 sizeof(map->grants[0]) * op.count) != 0) {
586 gntdev_put_map(NULL, map);
587 return -EFAULT;
588 }
589
590 mutex_lock(&priv->lock);
591 gntdev_add_map(priv, map);
592 op.index = map->index << PAGE_SHIFT;
593 mutex_unlock(&priv->lock);
594
595 if (copy_to_user(u, &op, sizeof(op)) != 0)
596 return -EFAULT;
597
598 return 0;
599 }
600
601 static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv *priv,
602 struct ioctl_gntdev_unmap_grant_ref __user *u)
603 {
604 struct ioctl_gntdev_unmap_grant_ref op;
605 struct gntdev_grant_map *map;
606 int err = -ENOENT;
607
608 if (copy_from_user(&op, u, sizeof(op)) != 0)
609 return -EFAULT;
610 pr_debug("priv %p, del %d+%d\n", priv, (int)op.index, (int)op.count);
611
612 mutex_lock(&priv->lock);
613 map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count);
614 if (map) {
615 list_del(&map->next);
616 err = 0;
617 }
618 mutex_unlock(&priv->lock);
619 if (map)
620 gntdev_put_map(priv, map);
621 return err;
622 }
623
624 static long gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv *priv,
625 struct ioctl_gntdev_get_offset_for_vaddr __user *u)
626 {
627 struct ioctl_gntdev_get_offset_for_vaddr op;
628 struct vm_area_struct *vma;
629 struct gntdev_grant_map *map;
630 int rv = -EINVAL;
631
632 if (copy_from_user(&op, u, sizeof(op)) != 0)
633 return -EFAULT;
634 pr_debug("priv %p, offset for vaddr %lx\n", priv, (unsigned long)op.vaddr);
635
636 mmap_read_lock(current->mm);
637 vma = find_vma(current->mm, op.vaddr);
638 if (!vma || vma->vm_ops != &gntdev_vmops)
639 goto out_unlock;
640
641 map = vma->vm_private_data;
642 if (!map)
643 goto out_unlock;
644
645 op.offset = map->index << PAGE_SHIFT;
646 op.count = map->count;
647 rv = 0;
648
649 out_unlock:
650 mmap_read_unlock(current->mm);
651
652 if (rv == 0 && copy_to_user(u, &op, sizeof(op)) != 0)
653 return -EFAULT;
654 return rv;
655 }
656
657 static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u)
658 {
659 struct ioctl_gntdev_unmap_notify op;
660 struct gntdev_grant_map *map;
661 int rc;
662 int out_flags;
663 evtchn_port_t out_event;
664
665 if (copy_from_user(&op, u, sizeof(op)))
666 return -EFAULT;
667
668 if (op.action & ~(UNMAP_NOTIFY_CLEAR_BYTE|UNMAP_NOTIFY_SEND_EVENT))
669 return -EINVAL;
670
671 /* We need to grab a reference to the event channel we are going to use
672 * to send the notify before releasing the reference we may already have
673 * (if someone has called this ioctl twice). This is required so that
674 * it is possible to change the clear_byte part of the notification
675 * without disturbing the event channel part, which may now be the last
676 * reference to that event channel.
677 */
678 if (op.action & UNMAP_NOTIFY_SEND_EVENT) {
679 if (evtchn_get(op.event_channel_port))
680 return -EINVAL;
681 }
682
683 out_flags = op.action;
684 out_event = op.event_channel_port;
685
686 mutex_lock(&priv->lock);
687
688 list_for_each_entry(map, &priv->maps, next) {
689 uint64_t begin = map->index << PAGE_SHIFT;
690 uint64_t end = (map->index + map->count) << PAGE_SHIFT;
691 if (op.index >= begin && op.index < end)
692 goto found;
693 }
694 rc = -ENOENT;
695 goto unlock_out;
696
697 found:
698 if ((op.action & UNMAP_NOTIFY_CLEAR_BYTE) &&
699 (map->flags & GNTMAP_readonly)) {
700 rc = -EINVAL;
701 goto unlock_out;
702 }
703
704 out_flags = map->notify.flags;
705 out_event = map->notify.event;
706
707 map->notify.flags = op.action;
708 map->notify.addr = op.index - (map->index << PAGE_SHIFT);
709 map->notify.event = op.event_channel_port;
710
711 rc = 0;
712
713 unlock_out:
714 mutex_unlock(&priv->lock);
715
716 /* Drop the reference to the event channel we did not save in the map */
717 if (out_flags & UNMAP_NOTIFY_SEND_EVENT)
718 evtchn_put(out_event);
719
720 return rc;
721 }
722
723 #define GNTDEV_COPY_BATCH 16
724
725 struct gntdev_copy_batch {
726 struct gnttab_copy ops[GNTDEV_COPY_BATCH];
727 struct page *pages[GNTDEV_COPY_BATCH];
728 s16 __user *status[GNTDEV_COPY_BATCH];
729 unsigned int nr_ops;
730 unsigned int nr_pages;
731 bool writeable;
732 };
733
734 static int gntdev_get_page(struct gntdev_copy_batch *batch, void __user *virt,
735 unsigned long *gfn)
736 {
737 unsigned long addr = (unsigned long)virt;
738 struct page *page;
739 unsigned long xen_pfn;
740 int ret;
741
742 ret = pin_user_pages_fast(addr, 1, batch->writeable ? FOLL_WRITE : 0, &page);
743 if (ret < 0)
744 return ret;
745
746 batch->pages[batch->nr_pages++] = page;
747
748 xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(addr & ~PAGE_MASK);
749 *gfn = pfn_to_gfn(xen_pfn);
750
751 return 0;
752 }
753
754 static void gntdev_put_pages(struct gntdev_copy_batch *batch)
755 {
756 unpin_user_pages_dirty_lock(batch->pages, batch->nr_pages, batch->writeable);
757 batch->nr_pages = 0;
758 batch->writeable = false;
759 }
760
761 static int gntdev_copy(struct gntdev_copy_batch *batch)
762 {
763 unsigned int i;
764
765 gnttab_batch_copy(batch->ops, batch->nr_ops);
766 gntdev_put_pages(batch);
767
768 /*
769 * For each completed op, update the status if the op failed
770 * and all previous ops for the segment were successful.
771 */
772 for (i = 0; i < batch->nr_ops; i++) {
773 s16 status = batch->ops[i].status;
774 s16 old_status;
775
776 if (status == GNTST_okay)
777 continue;
778
779 if (__get_user(old_status, batch->status[i]))
780 return -EFAULT;
781
782 if (old_status != GNTST_okay)
783 continue;
784
785 if (__put_user(status, batch->status[i]))
786 return -EFAULT;
787 }
788
789 batch->nr_ops = 0;
790 return 0;
791 }
792
793 static int gntdev_grant_copy_seg(struct gntdev_copy_batch *batch,
794 struct gntdev_grant_copy_segment *seg,
795 s16 __user *status)
796 {
797 uint16_t copied = 0;
798
799 /*
800 * Disallow local -> local copies since there is only space in
801 * batch->pages for one page per-op and this would be a very
802 * expensive memcpy().
803 */
804 if (!(seg->flags & (GNTCOPY_source_gref | GNTCOPY_dest_gref)))
805 return -EINVAL;
806
807 /* Can't cross page if source/dest is a grant ref. */
808 if (seg->flags & GNTCOPY_source_gref) {
809 if (seg->source.foreign.offset + seg->len > XEN_PAGE_SIZE)
810 return -EINVAL;
811 }
812 if (seg->flags & GNTCOPY_dest_gref) {
813 if (seg->dest.foreign.offset + seg->len > XEN_PAGE_SIZE)
814 return -EINVAL;
815 }
816
817 if (put_user(GNTST_okay, status))
818 return -EFAULT;
819
820 while (copied < seg->len) {
821 struct gnttab_copy *op;
822 void __user *virt;
823 size_t len, off;
824 unsigned long gfn;
825 int ret;
826
827 if (batch->nr_ops >= GNTDEV_COPY_BATCH) {
828 ret = gntdev_copy(batch);
829 if (ret < 0)
830 return ret;
831 }
832
833 len = seg->len - copied;
834
835 op = &batch->ops[batch->nr_ops];
836 op->flags = 0;
837
838 if (seg->flags & GNTCOPY_source_gref) {
839 op->source.u.ref = seg->source.foreign.ref;
840 op->source.domid = seg->source.foreign.domid;
841 op->source.offset = seg->source.foreign.offset + copied;
842 op->flags |= GNTCOPY_source_gref;
843 } else {
844 virt = seg->source.virt + copied;
845 off = (unsigned long)virt & ~XEN_PAGE_MASK;
846 len = min(len, (size_t)XEN_PAGE_SIZE - off);
847 batch->writeable = false;
848
849 ret = gntdev_get_page(batch, virt, &gfn);
850 if (ret < 0)
851 return ret;
852
853 op->source.u.gmfn = gfn;
854 op->source.domid = DOMID_SELF;
855 op->source.offset = off;
856 }
857
858 if (seg->flags & GNTCOPY_dest_gref) {
859 op->dest.u.ref = seg->dest.foreign.ref;
860 op->dest.domid = seg->dest.foreign.domid;
861 op->dest.offset = seg->dest.foreign.offset + copied;
862 op->flags |= GNTCOPY_dest_gref;
863 } else {
864 virt = seg->dest.virt + copied;
865 off = (unsigned long)virt & ~XEN_PAGE_MASK;
866 len = min(len, (size_t)XEN_PAGE_SIZE - off);
867 batch->writeable = true;
868
869 ret = gntdev_get_page(batch, virt, &gfn);
870 if (ret < 0)
871 return ret;
872
873 op->dest.u.gmfn = gfn;
874 op->dest.domid = DOMID_SELF;
875 op->dest.offset = off;
876 }
877
878 op->len = len;
879 copied += len;
880
881 batch->status[batch->nr_ops] = status;
882 batch->nr_ops++;
883 }
884
885 return 0;
886 }
887
888 static long gntdev_ioctl_grant_copy(struct gntdev_priv *priv, void __user *u)
889 {
890 struct ioctl_gntdev_grant_copy copy;
891 struct gntdev_copy_batch batch;
892 unsigned int i;
893 int ret = 0;
894
895 if (copy_from_user(&copy, u, sizeof(copy)))
896 return -EFAULT;
897
898 batch.nr_ops = 0;
899 batch.nr_pages = 0;
900
901 for (i = 0; i < copy.count; i++) {
902 struct gntdev_grant_copy_segment seg;
903
904 if (copy_from_user(&seg, &copy.segments[i], sizeof(seg))) {
905 ret = -EFAULT;
906 goto out;
907 }
908
909 ret = gntdev_grant_copy_seg(&batch, &seg, &copy.segments[i].status);
910 if (ret < 0)
911 goto out;
912
913 cond_resched();
914 }
915 if (batch.nr_ops)
916 ret = gntdev_copy(&batch);
917 return ret;
918
919 out:
920 gntdev_put_pages(&batch);
921 return ret;
922 }
923
924 static long gntdev_ioctl(struct file *flip,
925 unsigned int cmd, unsigned long arg)
926 {
927 struct gntdev_priv *priv = flip->private_data;
928 void __user *ptr = (void __user *)arg;
929
930 switch (cmd) {
931 case IOCTL_GNTDEV_MAP_GRANT_REF:
932 return gntdev_ioctl_map_grant_ref(priv, ptr);
933
934 case IOCTL_GNTDEV_UNMAP_GRANT_REF:
935 return gntdev_ioctl_unmap_grant_ref(priv, ptr);
936
937 case IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR:
938 return gntdev_ioctl_get_offset_for_vaddr(priv, ptr);
939
940 case IOCTL_GNTDEV_SET_UNMAP_NOTIFY:
941 return gntdev_ioctl_notify(priv, ptr);
942
943 case IOCTL_GNTDEV_GRANT_COPY:
944 return gntdev_ioctl_grant_copy(priv, ptr);
945
946 #ifdef CONFIG_XEN_GNTDEV_DMABUF
947 case IOCTL_GNTDEV_DMABUF_EXP_FROM_REFS:
948 return gntdev_ioctl_dmabuf_exp_from_refs(priv, use_ptemod, ptr);
949
950 case IOCTL_GNTDEV_DMABUF_EXP_WAIT_RELEASED:
951 return gntdev_ioctl_dmabuf_exp_wait_released(priv, ptr);
952
953 case IOCTL_GNTDEV_DMABUF_IMP_TO_REFS:
954 return gntdev_ioctl_dmabuf_imp_to_refs(priv, ptr);
955
956 case IOCTL_GNTDEV_DMABUF_IMP_RELEASE:
957 return gntdev_ioctl_dmabuf_imp_release(priv, ptr);
958 #endif
959
960 default:
961 pr_debug("priv %p, unknown cmd %x\n", priv, cmd);
962 return -ENOIOCTLCMD;
963 }
964
965 return 0;
966 }
967
968 static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
969 {
970 struct gntdev_priv *priv = flip->private_data;
971 int index = vma->vm_pgoff;
972 int count = vma_pages(vma);
973 struct gntdev_grant_map *map;
974 int err = -EINVAL;
975
976 if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED))
977 return -EINVAL;
978
979 pr_debug("map %d+%d at %lx (pgoff %lx)\n",
980 index, count, vma->vm_start, vma->vm_pgoff);
981
982 mutex_lock(&priv->lock);
983 map = gntdev_find_map_index(priv, index, count);
984 if (!map)
985 goto unlock_out;
986 if (use_ptemod && map->vma)
987 goto unlock_out;
988 refcount_inc(&map->users);
989
990 vma->vm_ops = &gntdev_vmops;
991
992 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP | VM_MIXEDMAP;
993
994 if (use_ptemod)
995 vma->vm_flags |= VM_DONTCOPY;
996
997 vma->vm_private_data = map;
998 if (map->flags) {
999 if ((vma->vm_flags & VM_WRITE) &&
1000 (map->flags & GNTMAP_readonly))
1001 goto out_unlock_put;
1002 } else {
1003 map->flags = GNTMAP_host_map;
1004 if (!(vma->vm_flags & VM_WRITE))
1005 map->flags |= GNTMAP_readonly;
1006 }
1007
1008 if (use_ptemod) {
1009 map->vma = vma;
1010 err = mmu_interval_notifier_insert_locked(
1011 &map->notifier, vma->vm_mm, vma->vm_start,
1012 vma->vm_end - vma->vm_start, &gntdev_mmu_ops);
1013 if (err) {
1014 map->vma = NULL;
1015 goto out_unlock_put;
1016 }
1017 }
1018 mutex_unlock(&priv->lock);
1019
1020 if (use_ptemod) {
1021 /*
1022 * gntdev takes the address of the PTE in find_grant_ptes() and
1023 * passes it to the hypervisor in gntdev_map_grant_pages(). The
1024 * purpose of the notifier is to prevent the hypervisor pointer
1025 * to the PTE from going stale.
1026 *
1027 * Since this vma's mappings can't be touched without the
1028 * mmap_lock, and we are holding it now, there is no need for
1029 * the notifier_range locking pattern.
1030 */
1031 mmu_interval_read_begin(&map->notifier);
1032
1033 map->pages_vm_start = vma->vm_start;
1034 err = apply_to_page_range(vma->vm_mm, vma->vm_start,
1035 vma->vm_end - vma->vm_start,
1036 find_grant_ptes, map);
1037 if (err) {
1038 pr_warn("find_grant_ptes() failure.\n");
1039 goto out_put_map;
1040 }
1041 }
1042
1043 err = gntdev_map_grant_pages(map);
1044 if (err)
1045 goto out_put_map;
1046
1047 if (!use_ptemod) {
1048 err = vm_map_pages_zero(vma, map->pages, map->count);
1049 if (err)
1050 goto out_put_map;
1051 }
1052
1053 return 0;
1054
1055 unlock_out:
1056 mutex_unlock(&priv->lock);
1057 return err;
1058
1059 out_unlock_put:
1060 mutex_unlock(&priv->lock);
1061 out_put_map:
1062 if (use_ptemod) {
1063 unmap_grant_pages(map, 0, map->count);
1064 if (map->vma) {
1065 mmu_interval_notifier_remove(&map->notifier);
1066 map->vma = NULL;
1067 }
1068 }
1069 gntdev_put_map(priv, map);
1070 return err;
1071 }
1072
1073 static const struct file_operations gntdev_fops = {
1074 .owner = THIS_MODULE,
1075 .open = gntdev_open,
1076 .release = gntdev_release,
1077 .mmap = gntdev_mmap,
1078 .unlocked_ioctl = gntdev_ioctl
1079 };
1080
1081 static struct miscdevice gntdev_miscdev = {
1082 .minor = MISC_DYNAMIC_MINOR,
1083 .name = "xen/gntdev",
1084 .fops = &gntdev_fops,
1085 };
1086
1087 /* ------------------------------------------------------------------ */
1088
1089 static int __init gntdev_init(void)
1090 {
1091 int err;
1092
1093 if (!xen_domain())
1094 return -ENODEV;
1095
1096 use_ptemod = !xen_feature(XENFEAT_auto_translated_physmap);
1097
1098 err = misc_register(&gntdev_miscdev);
1099 if (err != 0) {
1100 pr_err("Could not register gntdev device\n");
1101 return err;
1102 }
1103 return 0;
1104 }
1105
1106 static void __exit gntdev_exit(void)
1107 {
1108 misc_deregister(&gntdev_miscdev);
1109 }
1110
1111 module_init(gntdev_init);
1112 module_exit(gntdev_exit);
1113
1114 /* ------------------------------------------------------------------ */
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