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treewide: remove redundant IS_ERR() before error code check
[linux/fpc-iii.git] / drivers / xen / gntdev.c
blob4fc83e3f5ad3d3ee838f7c03749db1855868a947
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 = kvcalloc(count, sizeof(add->grants[0]), GFP_KERNEL);
137 add->map_ops = kvcalloc(count, sizeof(add->map_ops[0]), GFP_KERNEL);
138 add->unmap_ops = kvcalloc(count, sizeof(add->unmap_ops[0]), GFP_KERNEL);
139 add->kmap_ops = kvcalloc(count, sizeof(add->kmap_ops[0]), GFP_KERNEL);
140 add->kunmap_ops = kvcalloc(count,
141 sizeof(add->kunmap_ops[0]), 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->kmap_ops ||
147 NULL == add->kunmap_ops ||
148 NULL == add->pages)
149 goto err;
150
151 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC
152 add->dma_flags = dma_flags;
153
154 /*
155 * Check if this mapping is requested to be backed
156 * by a DMA buffer.
157 */
158 if (dma_flags & (GNTDEV_DMA_FLAG_WC | GNTDEV_DMA_FLAG_COHERENT)) {
159 struct gnttab_dma_alloc_args args;
160
161 add->frames = kvcalloc(count, sizeof(add->frames[0]),
162 GFP_KERNEL);
163 if (!add->frames)
164 goto err;
165
166 /* Remember the device, so we can free DMA memory. */
167 add->dma_dev = priv->dma_dev;
168
169 args.dev = priv->dma_dev;
170 args.coherent = !!(dma_flags & GNTDEV_DMA_FLAG_COHERENT);
171 args.nr_pages = count;
172 args.pages = add->pages;
173 args.frames = add->frames;
174
175 if (gnttab_dma_alloc_pages(&args))
176 goto err;
177
178 add->dma_vaddr = args.vaddr;
179 add->dma_bus_addr = args.dev_bus_addr;
180 } else
181 #endif
182 if (gnttab_alloc_pages(count, add->pages))
183 goto err;
184
185 for (i = 0; i < count; i++) {
186 add->map_ops[i].handle = -1;
187 add->unmap_ops[i].handle = -1;
188 add->kmap_ops[i].handle = -1;
189 add->kunmap_ops[i].handle = -1;
190 }
191
192 add->index = 0;
193 add->count = count;
194 refcount_set(&add->users, 1);
195
196 return add;
197
198 err:
199 gntdev_free_map(add);
200 return NULL;
201 }
202
203 void gntdev_add_map(struct gntdev_priv *priv, struct gntdev_grant_map *add)
204 {
205 struct gntdev_grant_map *map;
206
207 list_for_each_entry(map, &priv->maps, next) {
208 if (add->index + add->count < map->index) {
209 list_add_tail(&add->next, &map->next);
210 goto done;
211 }
212 add->index = map->index + map->count;
213 }
214 list_add_tail(&add->next, &priv->maps);
215
216 done:
217 gntdev_print_maps(priv, "[new]", add->index);
218 }
219
220 static struct gntdev_grant_map *gntdev_find_map_index(struct gntdev_priv *priv,
221 int index, int count)
222 {
223 struct gntdev_grant_map *map;
224
225 list_for_each_entry(map, &priv->maps, next) {
226 if (map->index != index)
227 continue;
228 if (count && map->count != count)
229 continue;
230 return map;
231 }
232 return NULL;
233 }
234
235 void gntdev_put_map(struct gntdev_priv *priv, struct gntdev_grant_map *map)
236 {
237 if (!map)
238 return;
239
240 if (!refcount_dec_and_test(&map->users))
241 return;
242
243 if (map->notify.flags & UNMAP_NOTIFY_SEND_EVENT) {
244 notify_remote_via_evtchn(map->notify.event);
245 evtchn_put(map->notify.event);
246 }
247
248 if (map->pages && !use_ptemod)
249 unmap_grant_pages(map, 0, map->count);
250 gntdev_free_map(map);
251 }
252
253 /* ------------------------------------------------------------------ */
254
255 static int find_grant_ptes(pte_t *pte, unsigned long addr, void *data)
256 {
257 struct gntdev_grant_map *map = data;
258 unsigned int pgnr = (addr - map->vma->vm_start) >> PAGE_SHIFT;
259 int flags = map->flags | GNTMAP_application_map | GNTMAP_contains_pte;
260 u64 pte_maddr;
261
262 BUG_ON(pgnr >= map->count);
263 pte_maddr = arbitrary_virt_to_machine(pte).maddr;
264
265 /*
266 * Set the PTE as special to force get_user_pages_fast() fall
267 * back to the slow path. If this is not supported as part of
268 * the grant map, it will be done afterwards.
269 */
270 if (xen_feature(XENFEAT_gnttab_map_avail_bits))
271 flags |= (1 << _GNTMAP_guest_avail0);
272
273 gnttab_set_map_op(&map->map_ops[pgnr], pte_maddr, flags,
274 map->grants[pgnr].ref,
275 map->grants[pgnr].domid);
276 gnttab_set_unmap_op(&map->unmap_ops[pgnr], pte_maddr, flags,
277 -1 /* handle */);
278 return 0;
279 }
280
281 #ifdef CONFIG_X86
282 static int set_grant_ptes_as_special(pte_t *pte, unsigned long addr, void *data)
283 {
284 set_pte_at(current->mm, addr, pte, pte_mkspecial(*pte));
285 return 0;
286 }
287 #endif
288
289 int gntdev_map_grant_pages(struct gntdev_grant_map *map)
290 {
291 int i, err = 0;
292
293 if (!use_ptemod) {
294 /* Note: it could already be mapped */
295 if (map->map_ops[0].handle != -1)
296 return 0;
297 for (i = 0; i < map->count; i++) {
298 unsigned long addr = (unsigned long)
299 pfn_to_kaddr(page_to_pfn(map->pages[i]));
300 gnttab_set_map_op(&map->map_ops[i], addr, map->flags,
301 map->grants[i].ref,
302 map->grants[i].domid);
303 gnttab_set_unmap_op(&map->unmap_ops[i], addr,
304 map->flags, -1 /* handle */);
305 }
306 } else {
307 /*
308 * Setup the map_ops corresponding to the pte entries pointing
309 * to the kernel linear addresses of the struct pages.
310 * These ptes are completely different from the user ptes dealt
311 * with find_grant_ptes.
312 */
313 for (i = 0; i < map->count; i++) {
314 unsigned long address = (unsigned long)
315 pfn_to_kaddr(page_to_pfn(map->pages[i]));
316 BUG_ON(PageHighMem(map->pages[i]));
317
318 gnttab_set_map_op(&map->kmap_ops[i], address,
319 map->flags | GNTMAP_host_map,
320 map->grants[i].ref,
321 map->grants[i].domid);
322 gnttab_set_unmap_op(&map->kunmap_ops[i], address,
323 map->flags | GNTMAP_host_map, -1);
324 }
325 }
326
327 pr_debug("map %d+%d\n", map->index, map->count);
328 err = gnttab_map_refs(map->map_ops, use_ptemod ? map->kmap_ops : NULL,
329 map->pages, map->count);
330 if (err)
331 return err;
332
333 for (i = 0; i < map->count; i++) {
334 if (map->map_ops[i].status) {
335 err = -EINVAL;
336 continue;
337 }
338
339 map->unmap_ops[i].handle = map->map_ops[i].handle;
340 if (use_ptemod)
341 map->kunmap_ops[i].handle = map->kmap_ops[i].handle;
342 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC
343 else if (map->dma_vaddr) {
344 unsigned long bfn;
345
346 bfn = pfn_to_bfn(page_to_pfn(map->pages[i]));
347 map->unmap_ops[i].dev_bus_addr = __pfn_to_phys(bfn);
348 }
349 #endif
350 }
351 return err;
352 }
353
354 static int __unmap_grant_pages(struct gntdev_grant_map *map, int offset,
355 int pages)
356 {
357 int i, err = 0;
358 struct gntab_unmap_queue_data unmap_data;
359
360 if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) {
361 int pgno = (map->notify.addr >> PAGE_SHIFT);
362 if (pgno >= offset && pgno < offset + pages) {
363 /* No need for kmap, pages are in lowmem */
364 uint8_t *tmp = pfn_to_kaddr(page_to_pfn(map->pages[pgno]));
365 tmp[map->notify.addr & (PAGE_SIZE-1)] = 0;
366 map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE;
367 }
368 }
369
370 unmap_data.unmap_ops = map->unmap_ops + offset;
371 unmap_data.kunmap_ops = use_ptemod ? map->kunmap_ops + offset : NULL;
372 unmap_data.pages = map->pages + offset;
373 unmap_data.count = pages;
374
375 err = gnttab_unmap_refs_sync(&unmap_data);
376 if (err)
377 return err;
378
379 for (i = 0; i < pages; i++) {
380 if (map->unmap_ops[offset+i].status)
381 err = -EINVAL;
382 pr_debug("unmap handle=%d st=%d\n",
383 map->unmap_ops[offset+i].handle,
384 map->unmap_ops[offset+i].status);
385 map->unmap_ops[offset+i].handle = -1;
386 }
387 return err;
388 }
389
390 static int unmap_grant_pages(struct gntdev_grant_map *map, int offset,
391 int pages)
392 {
393 int range, err = 0;
394
395 pr_debug("unmap %d+%d [%d+%d]\n", map->index, map->count, offset, pages);
396
397 /* It is possible the requested range will have a "hole" where we
398 * already unmapped some of the grants. Only unmap valid ranges.
399 */
400 while (pages && !err) {
401 while (pages && map->unmap_ops[offset].handle == -1) {
402 offset++;
403 pages--;
404 }
405 range = 0;
406 while (range < pages) {
407 if (map->unmap_ops[offset+range].handle == -1)
408 break;
409 range++;
410 }
411 err = __unmap_grant_pages(map, offset, range);
412 offset += range;
413 pages -= range;
414 }
415
416 return err;
417 }
418
419 /* ------------------------------------------------------------------ */
420
421 static void gntdev_vma_open(struct vm_area_struct *vma)
422 {
423 struct gntdev_grant_map *map = vma->vm_private_data;
424
425 pr_debug("gntdev_vma_open %p\n", vma);
426 refcount_inc(&map->users);
427 }
428
429 static void gntdev_vma_close(struct vm_area_struct *vma)
430 {
431 struct gntdev_grant_map *map = vma->vm_private_data;
432 struct file *file = vma->vm_file;
433 struct gntdev_priv *priv = file->private_data;
434
435 pr_debug("gntdev_vma_close %p\n", vma);
436 if (use_ptemod) {
437 WARN_ON(map->vma != vma);
438 mmu_interval_notifier_remove(&map->notifier);
439 map->vma = NULL;
440 }
441 vma->vm_private_data = NULL;
442 gntdev_put_map(priv, map);
443 }
444
445 static struct page *gntdev_vma_find_special_page(struct vm_area_struct *vma,
446 unsigned long addr)
447 {
448 struct gntdev_grant_map *map = vma->vm_private_data;
449
450 return map->pages[(addr - map->pages_vm_start) >> PAGE_SHIFT];
451 }
452
453 static const struct vm_operations_struct gntdev_vmops = {
454 .open = gntdev_vma_open,
455 .close = gntdev_vma_close,
456 .find_special_page = gntdev_vma_find_special_page,
457 };
458
459 /* ------------------------------------------------------------------ */
460
461 static bool gntdev_invalidate(struct mmu_interval_notifier *mn,
462 const struct mmu_notifier_range *range,
463 unsigned long cur_seq)
464 {
465 struct gntdev_grant_map *map =
466 container_of(mn, struct gntdev_grant_map, notifier);
467 unsigned long mstart, mend;
468 int err;
469
470 if (!mmu_notifier_range_blockable(range))
471 return false;
472
473 /*
474 * If the VMA is split or otherwise changed the notifier is not
475 * updated, but we don't want to process VA's outside the modified
476 * VMA. FIXME: It would be much more understandable to just prevent
477 * modifying the VMA in the first place.
478 */
479 if (map->vma->vm_start >= range->end ||
480 map->vma->vm_end <= range->start)
481 return true;
482
483 mstart = max(range->start, map->vma->vm_start);
484 mend = min(range->end, map->vma->vm_end);
485 pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n",
486 map->index, map->count,
487 map->vma->vm_start, map->vma->vm_end,
488 range->start, range->end, mstart, mend);
489 err = unmap_grant_pages(map,
490 (mstart - map->vma->vm_start) >> PAGE_SHIFT,
491 (mend - mstart) >> PAGE_SHIFT);
492 WARN_ON(err);
493
494 return true;
495 }
496
497 static const struct mmu_interval_notifier_ops gntdev_mmu_ops = {
498 .invalidate = gntdev_invalidate,
499 };
500
501 /* ------------------------------------------------------------------ */
502
503 static int gntdev_open(struct inode *inode, struct file *flip)
504 {
505 struct gntdev_priv *priv;
506
507 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
508 if (!priv)
509 return -ENOMEM;
510
511 INIT_LIST_HEAD(&priv->maps);
512 mutex_init(&priv->lock);
513
514 #ifdef CONFIG_XEN_GNTDEV_DMABUF
515 priv->dmabuf_priv = gntdev_dmabuf_init(flip);
516 if (IS_ERR(priv->dmabuf_priv)) {
517 int ret = PTR_ERR(priv->dmabuf_priv);
518
519 kfree(priv);
520 return ret;
521 }
522 #endif
523
524 flip->private_data = priv;
525 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC
526 priv->dma_dev = gntdev_miscdev.this_device;
527 dma_coerce_mask_and_coherent(priv->dma_dev, DMA_BIT_MASK(64));
528 #endif
529 pr_debug("priv %p\n", priv);
530
531 return 0;
532 }
533
534 static int gntdev_release(struct inode *inode, struct file *flip)
535 {
536 struct gntdev_priv *priv = flip->private_data;
537 struct gntdev_grant_map *map;
538
539 pr_debug("priv %p\n", priv);
540
541 mutex_lock(&priv->lock);
542 while (!list_empty(&priv->maps)) {
543 map = list_entry(priv->maps.next,
544 struct gntdev_grant_map, next);
545 list_del(&map->next);
546 gntdev_put_map(NULL /* already removed */, map);
547 }
548 mutex_unlock(&priv->lock);
549
550 #ifdef CONFIG_XEN_GNTDEV_DMABUF
551 gntdev_dmabuf_fini(priv->dmabuf_priv);
552 #endif
553
554 kfree(priv);
555 return 0;
556 }
557
558 static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv,
559 struct ioctl_gntdev_map_grant_ref __user *u)
560 {
561 struct ioctl_gntdev_map_grant_ref op;
562 struct gntdev_grant_map *map;
563 int err;
564
565 if (copy_from_user(&op, u, sizeof(op)) != 0)
566 return -EFAULT;
567 pr_debug("priv %p, add %d\n", priv, op.count);
568 if (unlikely(gntdev_test_page_count(op.count)))
569 return -EINVAL;
570
571 err = -ENOMEM;
572 map = gntdev_alloc_map(priv, op.count, 0 /* This is not a dma-buf. */);
573 if (!map)
574 return err;
575
576 if (copy_from_user(map->grants, &u->refs,
577 sizeof(map->grants[0]) * op.count) != 0) {
578 gntdev_put_map(NULL, map);
579 return -EFAULT;
580 }
581
582 mutex_lock(&priv->lock);
583 gntdev_add_map(priv, map);
584 op.index = map->index << PAGE_SHIFT;
585 mutex_unlock(&priv->lock);
586
587 if (copy_to_user(u, &op, sizeof(op)) != 0)
588 return -EFAULT;
589
590 return 0;
591 }
592
593 static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv *priv,
594 struct ioctl_gntdev_unmap_grant_ref __user *u)
595 {
596 struct ioctl_gntdev_unmap_grant_ref op;
597 struct gntdev_grant_map *map;
598 int err = -ENOENT;
599
600 if (copy_from_user(&op, u, sizeof(op)) != 0)
601 return -EFAULT;
602 pr_debug("priv %p, del %d+%d\n", priv, (int)op.index, (int)op.count);
603
604 mutex_lock(&priv->lock);
605 map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count);
606 if (map) {
607 list_del(&map->next);
608 err = 0;
609 }
610 mutex_unlock(&priv->lock);
611 if (map)
612 gntdev_put_map(priv, map);
613 return err;
614 }
615
616 static long gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv *priv,
617 struct ioctl_gntdev_get_offset_for_vaddr __user *u)
618 {
619 struct ioctl_gntdev_get_offset_for_vaddr op;
620 struct vm_area_struct *vma;
621 struct gntdev_grant_map *map;
622 int rv = -EINVAL;
623
624 if (copy_from_user(&op, u, sizeof(op)) != 0)
625 return -EFAULT;
626 pr_debug("priv %p, offset for vaddr %lx\n", priv, (unsigned long)op.vaddr);
627
628 down_read(&current->mm->mmap_sem);
629 vma = find_vma(current->mm, op.vaddr);
630 if (!vma || vma->vm_ops != &gntdev_vmops)
631 goto out_unlock;
632
633 map = vma->vm_private_data;
634 if (!map)
635 goto out_unlock;
636
637 op.offset = map->index << PAGE_SHIFT;
638 op.count = map->count;
639 rv = 0;
640
641 out_unlock:
642 up_read(&current->mm->mmap_sem);
643
644 if (rv == 0 && copy_to_user(u, &op, sizeof(op)) != 0)
645 return -EFAULT;
646 return rv;
647 }
648
649 static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u)
650 {
651 struct ioctl_gntdev_unmap_notify op;
652 struct gntdev_grant_map *map;
653 int rc;
654 int out_flags;
655 unsigned int out_event;
656
657 if (copy_from_user(&op, u, sizeof(op)))
658 return -EFAULT;
659
660 if (op.action & ~(UNMAP_NOTIFY_CLEAR_BYTE|UNMAP_NOTIFY_SEND_EVENT))
661 return -EINVAL;
662
663 /* We need to grab a reference to the event channel we are going to use
664 * to send the notify before releasing the reference we may already have
665 * (if someone has called this ioctl twice). This is required so that
666 * it is possible to change the clear_byte part of the notification
667 * without disturbing the event channel part, which may now be the last
668 * reference to that event channel.
669 */
670 if (op.action & UNMAP_NOTIFY_SEND_EVENT) {
671 if (evtchn_get(op.event_channel_port))
672 return -EINVAL;
673 }
674
675 out_flags = op.action;
676 out_event = op.event_channel_port;
677
678 mutex_lock(&priv->lock);
679
680 list_for_each_entry(map, &priv->maps, next) {
681 uint64_t begin = map->index << PAGE_SHIFT;
682 uint64_t end = (map->index + map->count) << PAGE_SHIFT;
683 if (op.index >= begin && op.index < end)
684 goto found;
685 }
686 rc = -ENOENT;
687 goto unlock_out;
688
689 found:
690 if ((op.action & UNMAP_NOTIFY_CLEAR_BYTE) &&
691 (map->flags & GNTMAP_readonly)) {
692 rc = -EINVAL;
693 goto unlock_out;
694 }
695
696 out_flags = map->notify.flags;
697 out_event = map->notify.event;
698
699 map->notify.flags = op.action;
700 map->notify.addr = op.index - (map->index << PAGE_SHIFT);
701 map->notify.event = op.event_channel_port;
702
703 rc = 0;
704
705 unlock_out:
706 mutex_unlock(&priv->lock);
707
708 /* Drop the reference to the event channel we did not save in the map */
709 if (out_flags & UNMAP_NOTIFY_SEND_EVENT)
710 evtchn_put(out_event);
711
712 return rc;
713 }
714
715 #define GNTDEV_COPY_BATCH 16
716
717 struct gntdev_copy_batch {
718 struct gnttab_copy ops[GNTDEV_COPY_BATCH];
719 struct page *pages[GNTDEV_COPY_BATCH];
720 s16 __user *status[GNTDEV_COPY_BATCH];
721 unsigned int nr_ops;
722 unsigned int nr_pages;
723 };
724
725 static int gntdev_get_page(struct gntdev_copy_batch *batch, void __user *virt,
726 bool writeable, unsigned long *gfn)
727 {
728 unsigned long addr = (unsigned long)virt;
729 struct page *page;
730 unsigned long xen_pfn;
731 int ret;
732
733 ret = get_user_pages_fast(addr, 1, writeable ? FOLL_WRITE : 0, &page);
734 if (ret < 0)
735 return ret;
736
737 batch->pages[batch->nr_pages++] = page;
738
739 xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(addr & ~PAGE_MASK);
740 *gfn = pfn_to_gfn(xen_pfn);
741
742 return 0;
743 }
744
745 static void gntdev_put_pages(struct gntdev_copy_batch *batch)
746 {
747 unsigned int i;
748
749 for (i = 0; i < batch->nr_pages; i++)
750 put_page(batch->pages[i]);
751 batch->nr_pages = 0;
752 }
753
754 static int gntdev_copy(struct gntdev_copy_batch *batch)
755 {
756 unsigned int i;
757
758 gnttab_batch_copy(batch->ops, batch->nr_ops);
759 gntdev_put_pages(batch);
760
761 /*
762 * For each completed op, update the status if the op failed
763 * and all previous ops for the segment were successful.
764 */
765 for (i = 0; i < batch->nr_ops; i++) {
766 s16 status = batch->ops[i].status;
767 s16 old_status;
768
769 if (status == GNTST_okay)
770 continue;
771
772 if (__get_user(old_status, batch->status[i]))
773 return -EFAULT;
774
775 if (old_status != GNTST_okay)
776 continue;
777
778 if (__put_user(status, batch->status[i]))
779 return -EFAULT;
780 }
781
782 batch->nr_ops = 0;
783 return 0;
784 }
785
786 static int gntdev_grant_copy_seg(struct gntdev_copy_batch *batch,
787 struct gntdev_grant_copy_segment *seg,
788 s16 __user *status)
789 {
790 uint16_t copied = 0;
791
792 /*
793 * Disallow local -> local copies since there is only space in
794 * batch->pages for one page per-op and this would be a very
795 * expensive memcpy().
796 */
797 if (!(seg->flags & (GNTCOPY_source_gref | GNTCOPY_dest_gref)))
798 return -EINVAL;
799
800 /* Can't cross page if source/dest is a grant ref. */
801 if (seg->flags & GNTCOPY_source_gref) {
802 if (seg->source.foreign.offset + seg->len > XEN_PAGE_SIZE)
803 return -EINVAL;
804 }
805 if (seg->flags & GNTCOPY_dest_gref) {
806 if (seg->dest.foreign.offset + seg->len > XEN_PAGE_SIZE)
807 return -EINVAL;
808 }
809
810 if (put_user(GNTST_okay, status))
811 return -EFAULT;
812
813 while (copied < seg->len) {
814 struct gnttab_copy *op;
815 void __user *virt;
816 size_t len, off;
817 unsigned long gfn;
818 int ret;
819
820 if (batch->nr_ops >= GNTDEV_COPY_BATCH) {
821 ret = gntdev_copy(batch);
822 if (ret < 0)
823 return ret;
824 }
825
826 len = seg->len - copied;
827
828 op = &batch->ops[batch->nr_ops];
829 op->flags = 0;
830
831 if (seg->flags & GNTCOPY_source_gref) {
832 op->source.u.ref = seg->source.foreign.ref;
833 op->source.domid = seg->source.foreign.domid;
834 op->source.offset = seg->source.foreign.offset + copied;
835 op->flags |= GNTCOPY_source_gref;
836 } else {
837 virt = seg->source.virt + copied;
838 off = (unsigned long)virt & ~XEN_PAGE_MASK;
839 len = min(len, (size_t)XEN_PAGE_SIZE - off);
840
841 ret = gntdev_get_page(batch, virt, false, &gfn);
842 if (ret < 0)
843 return ret;
844
845 op->source.u.gmfn = gfn;
846 op->source.domid = DOMID_SELF;
847 op->source.offset = off;
848 }
849
850 if (seg->flags & GNTCOPY_dest_gref) {
851 op->dest.u.ref = seg->dest.foreign.ref;
852 op->dest.domid = seg->dest.foreign.domid;
853 op->dest.offset = seg->dest.foreign.offset + copied;
854 op->flags |= GNTCOPY_dest_gref;
855 } else {
856 virt = seg->dest.virt + copied;
857 off = (unsigned long)virt & ~XEN_PAGE_MASK;
858 len = min(len, (size_t)XEN_PAGE_SIZE - off);
859
860 ret = gntdev_get_page(batch, virt, true, &gfn);
861 if (ret < 0)
862 return ret;
863
864 op->dest.u.gmfn = gfn;
865 op->dest.domid = DOMID_SELF;
866 op->dest.offset = off;
867 }
868
869 op->len = len;
870 copied += len;
871
872 batch->status[batch->nr_ops] = status;
873 batch->nr_ops++;
874 }
875
876 return 0;
877 }
878
879 static long gntdev_ioctl_grant_copy(struct gntdev_priv *priv, void __user *u)
880 {
881 struct ioctl_gntdev_grant_copy copy;
882 struct gntdev_copy_batch batch;
883 unsigned int i;
884 int ret = 0;
885
886 if (copy_from_user(&copy, u, sizeof(copy)))
887 return -EFAULT;
888
889 batch.nr_ops = 0;
890 batch.nr_pages = 0;
891
892 for (i = 0; i < copy.count; i++) {
893 struct gntdev_grant_copy_segment seg;
894
895 if (copy_from_user(&seg, &copy.segments[i], sizeof(seg))) {
896 ret = -EFAULT;
897 goto out;
898 }
899
900 ret = gntdev_grant_copy_seg(&batch, &seg, &copy.segments[i].status);
901 if (ret < 0)
902 goto out;
903
904 cond_resched();
905 }
906 if (batch.nr_ops)
907 ret = gntdev_copy(&batch);
908 return ret;
909
910 out:
911 gntdev_put_pages(&batch);
912 return ret;
913 }
914
915 static long gntdev_ioctl(struct file *flip,
916 unsigned int cmd, unsigned long arg)
917 {
918 struct gntdev_priv *priv = flip->private_data;
919 void __user *ptr = (void __user *)arg;
920
921 switch (cmd) {
922 case IOCTL_GNTDEV_MAP_GRANT_REF:
923 return gntdev_ioctl_map_grant_ref(priv, ptr);
924
925 case IOCTL_GNTDEV_UNMAP_GRANT_REF:
926 return gntdev_ioctl_unmap_grant_ref(priv, ptr);
927
928 case IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR:
929 return gntdev_ioctl_get_offset_for_vaddr(priv, ptr);
930
931 case IOCTL_GNTDEV_SET_UNMAP_NOTIFY:
932 return gntdev_ioctl_notify(priv, ptr);
933
934 case IOCTL_GNTDEV_GRANT_COPY:
935 return gntdev_ioctl_grant_copy(priv, ptr);
936
937 #ifdef CONFIG_XEN_GNTDEV_DMABUF
938 case IOCTL_GNTDEV_DMABUF_EXP_FROM_REFS:
939 return gntdev_ioctl_dmabuf_exp_from_refs(priv, use_ptemod, ptr);
940
941 case IOCTL_GNTDEV_DMABUF_EXP_WAIT_RELEASED:
942 return gntdev_ioctl_dmabuf_exp_wait_released(priv, ptr);
943
944 case IOCTL_GNTDEV_DMABUF_IMP_TO_REFS:
945 return gntdev_ioctl_dmabuf_imp_to_refs(priv, ptr);
946
947 case IOCTL_GNTDEV_DMABUF_IMP_RELEASE:
948 return gntdev_ioctl_dmabuf_imp_release(priv, ptr);
949 #endif
950
951 default:
952 pr_debug("priv %p, unknown cmd %x\n", priv, cmd);
953 return -ENOIOCTLCMD;
954 }
955
956 return 0;
957 }
958
959 static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
960 {
961 struct gntdev_priv *priv = flip->private_data;
962 int index = vma->vm_pgoff;
963 int count = vma_pages(vma);
964 struct gntdev_grant_map *map;
965 int err = -EINVAL;
966
967 if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED))
968 return -EINVAL;
969
970 pr_debug("map %d+%d at %lx (pgoff %lx)\n",
971 index, count, vma->vm_start, vma->vm_pgoff);
972
973 mutex_lock(&priv->lock);
974 map = gntdev_find_map_index(priv, index, count);
975 if (!map)
976 goto unlock_out;
977 if (use_ptemod && map->vma)
978 goto unlock_out;
979 refcount_inc(&map->users);
980
981 vma->vm_ops = &gntdev_vmops;
982
983 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP | VM_MIXEDMAP;
984
985 if (use_ptemod)
986 vma->vm_flags |= VM_DONTCOPY;
987
988 vma->vm_private_data = map;
989 if (map->flags) {
990 if ((vma->vm_flags & VM_WRITE) &&
991 (map->flags & GNTMAP_readonly))
992 goto out_unlock_put;
993 } else {
994 map->flags = GNTMAP_host_map;
995 if (!(vma->vm_flags & VM_WRITE))
996 map->flags |= GNTMAP_readonly;
997 }
998
999 if (use_ptemod) {
1000 map->vma = vma;
1001 err = mmu_interval_notifier_insert_locked(
1002 &map->notifier, vma->vm_mm, vma->vm_start,
1003 vma->vm_end - vma->vm_start, &gntdev_mmu_ops);
1004 if (err)
1005 goto out_unlock_put;
1006 }
1007 mutex_unlock(&priv->lock);
1008
1009 /*
1010 * gntdev takes the address of the PTE in find_grant_ptes() and passes
1011 * it to the hypervisor in gntdev_map_grant_pages(). The purpose of
1012 * the notifier is to prevent the hypervisor pointer to the PTE from
1013 * going stale.
1014 *
1015 * Since this vma's mappings can't be touched without the mmap_sem,
1016 * and we are holding it now, there is no need for the notifier_range
1017 * locking pattern.
1018 */
1019 mmu_interval_read_begin(&map->notifier);
1020
1021 if (use_ptemod) {
1022 map->pages_vm_start = vma->vm_start;
1023 err = apply_to_page_range(vma->vm_mm, vma->vm_start,
1024 vma->vm_end - vma->vm_start,
1025 find_grant_ptes, map);
1026 if (err) {
1027 pr_warn("find_grant_ptes() failure.\n");
1028 goto out_put_map;
1029 }
1030 }
1031
1032 err = gntdev_map_grant_pages(map);
1033 if (err)
1034 goto out_put_map;
1035
1036 if (!use_ptemod) {
1037 err = vm_map_pages_zero(vma, map->pages, map->count);
1038 if (err)
1039 goto out_put_map;
1040 } else {
1041 #ifdef CONFIG_X86
1042 /*
1043 * If the PTEs were not made special by the grant map
1044 * hypercall, do so here.
1045 *
1046 * This is racy since the mapping is already visible
1047 * to userspace but userspace should be well-behaved
1048 * enough to not touch it until the mmap() call
1049 * returns.
1050 */
1051 if (!xen_feature(XENFEAT_gnttab_map_avail_bits)) {
1052 apply_to_page_range(vma->vm_mm, vma->vm_start,
1053 vma->vm_end - vma->vm_start,
1054 set_grant_ptes_as_special, NULL);
1055 }
1056 #endif
1057 }
1058
1059 return 0;
1060
1061 unlock_out:
1062 mutex_unlock(&priv->lock);
1063 return err;
1064
1065 out_unlock_put:
1066 mutex_unlock(&priv->lock);
1067 out_put_map:
1068 if (use_ptemod) {
1069 unmap_grant_pages(map, 0, map->count);
1070 if (map->vma) {
1071 mmu_interval_notifier_remove(&map->notifier);
1072 map->vma = NULL;
1073 }
1074 }
1075 gntdev_put_map(priv, map);
1076 return err;
1077 }
1078
1079 static const struct file_operations gntdev_fops = {
1080 .owner = THIS_MODULE,
1081 .open = gntdev_open,
1082 .release = gntdev_release,
1083 .mmap = gntdev_mmap,
1084 .unlocked_ioctl = gntdev_ioctl
1085 };
1086
1087 static struct miscdevice gntdev_miscdev = {
1088 .minor = MISC_DYNAMIC_MINOR,
1089 .name = "xen/gntdev",
1090 .fops = &gntdev_fops,
1091 };
1092
1093 /* ------------------------------------------------------------------ */
1094
1095 static int __init gntdev_init(void)
1096 {
1097 int err;
1098
1099 if (!xen_domain())
1100 return -ENODEV;
1101
1102 use_ptemod = !xen_feature(XENFEAT_auto_translated_physmap);
1103
1104 err = misc_register(&gntdev_miscdev);
1105 if (err != 0) {
1106 pr_err("Could not register gntdev device\n");
1107 return err;
1108 }
1109 return 0;
1110 }
1111
1112 static void __exit gntdev_exit(void)
1113 {
1114 misc_deregister(&gntdev_miscdev);
1115 }
1116
1117 module_init(gntdev_init);
1118 module_exit(gntdev_exit);
1119
1120 /* ------------------------------------------------------------------ */
Linux with added FPC-III support