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 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 */
19
20 #undef DEBUG
21
22 #include <linux/module.h>
23 #include <linux/kernel.h>
24 #include <linux/init.h>
25 #include <linux/miscdevice.h>
26 #include <linux/fs.h>
27 #include <linux/mm.h>
28 #include <linux/mman.h>
29 #include <linux/mmu_notifier.h>
30 #include <linux/types.h>
31 #include <linux/uaccess.h>
32 #include <linux/sched.h>
33 #include <linux/spinlock.h>
34 #include <linux/slab.h>
35 #include <linux/highmem.h>
36
37 #include <xen/xen.h>
38 #include <xen/grant_table.h>
39 #include <xen/balloon.h>
40 #include <xen/gntdev.h>
41 #include <xen/events.h>
42 #include <asm/xen/hypervisor.h>
43 #include <asm/xen/hypercall.h>
44 #include <asm/xen/page.h>
45
46 MODULE_LICENSE("GPL");
47 MODULE_AUTHOR("Derek G. Murray <Derek.Murray@cl.cam.ac.uk>, "
48 "Gerd Hoffmann <kraxel@redhat.com>");
49 MODULE_DESCRIPTION("User-space granted page access driver");
50
51 static int limit = 1024*1024;
52 module_param(limit, int, 0644);
53 MODULE_PARM_DESC(limit, "Maximum number of grants that may be mapped by "
54 "the gntdev device");
55
56 static atomic_t pages_mapped = ATOMIC_INIT(0);
57
58 static int use_ptemod;
59
60 struct gntdev_priv {
61 struct list_head maps;
62 /* lock protects maps from concurrent changes */
63 spinlock_t lock;
64 struct mm_struct *mm;
65 struct mmu_notifier mn;
66 };
67
68 struct unmap_notify {
69 int flags;
70 /* Address relative to the start of the grant_map */
71 int addr;
72 int event;
73 };
74
75 struct grant_map {
76 struct list_head next;
77 struct vm_area_struct *vma;
78 int index;
79 int count;
80 int flags;
81 atomic_t users;
82 struct unmap_notify notify;
83 struct ioctl_gntdev_grant_ref *grants;
84 struct gnttab_map_grant_ref *map_ops;
85 struct gnttab_unmap_grant_ref *unmap_ops;
86 struct gnttab_map_grant_ref *kmap_ops;
87 struct page **pages;
88 };
89
90 static int unmap_grant_pages(struct grant_map *map, int offset, int pages);
91
92 /* ------------------------------------------------------------------ */
93
gntdev_print_maps(struct gntdev_priv * priv,char * text,int text_index)94 static void gntdev_print_maps(struct gntdev_priv *priv,
95 char *text, int text_index)
96 {
97 #ifdef DEBUG
98 struct grant_map *map;
99
100 pr_debug("%s: maps list (priv %p)\n", __func__, priv);
101 list_for_each_entry(map, &priv->maps, next)
102 pr_debug(" index %2d, count %2d %s\n",
103 map->index, map->count,
104 map->index == text_index && text ? text : "");
105 #endif
106 }
107
gntdev_free_map(struct grant_map * map)108 static void gntdev_free_map(struct grant_map *map)
109 {
110 if (map == NULL)
111 return;
112
113 if (map->pages)
114 free_xenballooned_pages(map->count, map->pages);
115 kfree(map->pages);
116 kfree(map->grants);
117 kfree(map->map_ops);
118 kfree(map->unmap_ops);
119 kfree(map->kmap_ops);
120 kfree(map);
121 }
122
gntdev_alloc_map(struct gntdev_priv * priv,int count)123 static struct grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count)
124 {
125 struct grant_map *add;
126 int i;
127
128 add = kzalloc(sizeof(struct grant_map), GFP_KERNEL);
129 if (NULL == add)
130 return NULL;
131
132 add->grants = kcalloc(count, sizeof(add->grants[0]), GFP_KERNEL);
133 add->map_ops = kcalloc(count, sizeof(add->map_ops[0]), GFP_KERNEL);
134 add->unmap_ops = kcalloc(count, sizeof(add->unmap_ops[0]), GFP_KERNEL);
135 add->kmap_ops = kcalloc(count, sizeof(add->kmap_ops[0]), GFP_KERNEL);
136 add->pages = kcalloc(count, sizeof(add->pages[0]), GFP_KERNEL);
137 if (NULL == add->grants ||
138 NULL == add->map_ops ||
139 NULL == add->unmap_ops ||
140 NULL == add->kmap_ops ||
141 NULL == add->pages)
142 goto err;
143
144 if (alloc_xenballooned_pages(count, add->pages, false /* lowmem */))
145 goto err;
146
147 for (i = 0; i < count; i++) {
148 add->map_ops[i].handle = -1;
149 add->unmap_ops[i].handle = -1;
150 add->kmap_ops[i].handle = -1;
151 }
152
153 add->index = 0;
154 add->count = count;
155 atomic_set(&add->users, 1);
156
157 return add;
158
159 err:
160 gntdev_free_map(add);
161 return NULL;
162 }
163
gntdev_add_map(struct gntdev_priv * priv,struct grant_map * add)164 static void gntdev_add_map(struct gntdev_priv *priv, struct grant_map *add)
165 {
166 struct grant_map *map;
167
168 list_for_each_entry(map, &priv->maps, next) {
169 if (add->index + add->count < map->index) {
170 list_add_tail(&add->next, &map->next);
171 goto done;
172 }
173 add->index = map->index + map->count;
174 }
175 list_add_tail(&add->next, &priv->maps);
176
177 done:
178 gntdev_print_maps(priv, "[new]", add->index);
179 }
180
gntdev_find_map_index(struct gntdev_priv * priv,int index,int count)181 static struct grant_map *gntdev_find_map_index(struct gntdev_priv *priv,
182 int index, int count)
183 {
184 struct grant_map *map;
185
186 list_for_each_entry(map, &priv->maps, next) {
187 if (map->index != index)
188 continue;
189 if (count && map->count != count)
190 continue;
191 return map;
192 }
193 return NULL;
194 }
195
gntdev_put_map(struct grant_map * map)196 static void gntdev_put_map(struct grant_map *map)
197 {
198 if (!map)
199 return;
200
201 if (!atomic_dec_and_test(&map->users))
202 return;
203
204 atomic_sub(map->count, &pages_mapped);
205
206 if (map->notify.flags & UNMAP_NOTIFY_SEND_EVENT) {
207 notify_remote_via_evtchn(map->notify.event);
208 evtchn_put(map->notify.event);
209 }
210
211 if (map->pages && !use_ptemod)
212 unmap_grant_pages(map, 0, map->count);
213 gntdev_free_map(map);
214 }
215
216 /* ------------------------------------------------------------------ */
217
find_grant_ptes(pte_t * pte,pgtable_t token,unsigned long addr,void * data)218 static int find_grant_ptes(pte_t *pte, pgtable_t token,
219 unsigned long addr, void *data)
220 {
221 struct grant_map *map = data;
222 unsigned int pgnr = (addr - map->vma->vm_start) >> PAGE_SHIFT;
223 int flags = map->flags | GNTMAP_application_map | GNTMAP_contains_pte;
224 u64 pte_maddr;
225
226 BUG_ON(pgnr >= map->count);
227 pte_maddr = arbitrary_virt_to_machine(pte).maddr;
228
229 gnttab_set_map_op(&map->map_ops[pgnr], pte_maddr, flags,
230 map->grants[pgnr].ref,
231 map->grants[pgnr].domid);
232 gnttab_set_unmap_op(&map->unmap_ops[pgnr], pte_maddr, flags,
233 -1 /* handle */);
234 return 0;
235 }
236
map_grant_pages(struct grant_map * map)237 static int map_grant_pages(struct grant_map *map)
238 {
239 int i, err = 0;
240
241 if (!use_ptemod) {
242 /* Note: it could already be mapped */
243 if (map->map_ops[0].handle != -1)
244 return 0;
245 for (i = 0; i < map->count; i++) {
246 unsigned long addr = (unsigned long)
247 pfn_to_kaddr(page_to_pfn(map->pages[i]));
248 gnttab_set_map_op(&map->map_ops[i], addr, map->flags,
249 map->grants[i].ref,
250 map->grants[i].domid);
251 gnttab_set_unmap_op(&map->unmap_ops[i], addr,
252 map->flags, -1 /* handle */);
253 }
254 } else {
255 /*
256 * Setup the map_ops corresponding to the pte entries pointing
257 * to the kernel linear addresses of the struct pages.
258 * These ptes are completely different from the user ptes dealt
259 * with find_grant_ptes.
260 */
261 for (i = 0; i < map->count; i++) {
262 unsigned level;
263 unsigned long address = (unsigned long)
264 pfn_to_kaddr(page_to_pfn(map->pages[i]));
265 pte_t *ptep;
266 u64 pte_maddr = 0;
267 BUG_ON(PageHighMem(map->pages[i]));
268
269 ptep = lookup_address(address, &level);
270 pte_maddr = arbitrary_virt_to_machine(ptep).maddr;
271 gnttab_set_map_op(&map->kmap_ops[i], pte_maddr,
272 map->flags |
273 GNTMAP_host_map |
274 GNTMAP_contains_pte,
275 map->grants[i].ref,
276 map->grants[i].domid);
277 }
278 }
279
280 pr_debug("map %d+%d\n", map->index, map->count);
281 err = gnttab_map_refs(map->map_ops, use_ptemod ? map->kmap_ops : NULL,
282 map->pages, map->count);
283 if (err)
284 return err;
285
286 for (i = 0; i < map->count; i++) {
287 if (map->map_ops[i].status)
288 err = -EINVAL;
289 else {
290 BUG_ON(map->map_ops[i].handle == -1);
291 map->unmap_ops[i].handle = map->map_ops[i].handle;
292 pr_debug("map handle=%d\n", map->map_ops[i].handle);
293 }
294 }
295 return err;
296 }
297
__unmap_grant_pages(struct grant_map * map,int offset,int pages)298 static int __unmap_grant_pages(struct grant_map *map, int offset, int pages)
299 {
300 int i, err = 0;
301
302 if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) {
303 int pgno = (map->notify.addr >> PAGE_SHIFT);
304 if (pgno >= offset && pgno < offset + pages && use_ptemod) {
305 void __user *tmp = (void __user *)
306 map->vma->vm_start + map->notify.addr;
307 err = copy_to_user(tmp, &err, 1);
308 if (err)
309 return -EFAULT;
310 map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE;
311 } else if (pgno >= offset && pgno < offset + pages) {
312 uint8_t *tmp = kmap(map->pages[pgno]);
313 tmp[map->notify.addr & (PAGE_SIZE-1)] = 0;
314 kunmap(map->pages[pgno]);
315 map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE;
316 }
317 }
318
319 err = gnttab_unmap_refs(map->unmap_ops + offset,
320 use_ptemod ? map->kmap_ops + offset : NULL, map->pages + offset,
321 pages);
322 if (err)
323 return err;
324
325 for (i = 0; i < pages; i++) {
326 if (map->unmap_ops[offset+i].status)
327 err = -EINVAL;
328 pr_debug("unmap handle=%d st=%d\n",
329 map->unmap_ops[offset+i].handle,
330 map->unmap_ops[offset+i].status);
331 map->unmap_ops[offset+i].handle = -1;
332 }
333 return err;
334 }
335
unmap_grant_pages(struct grant_map * map,int offset,int pages)336 static int unmap_grant_pages(struct grant_map *map, int offset, int pages)
337 {
338 int range, err = 0;
339
340 pr_debug("unmap %d+%d [%d+%d]\n", map->index, map->count, offset, pages);
341
342 /* It is possible the requested range will have a "hole" where we
343 * already unmapped some of the grants. Only unmap valid ranges.
344 */
345 while (pages && !err) {
346 while (pages && map->unmap_ops[offset].handle == -1) {
347 offset++;
348 pages--;
349 }
350 range = 0;
351 while (range < pages) {
352 if (map->unmap_ops[offset+range].handle == -1) {
353 range--;
354 break;
355 }
356 range++;
357 }
358 err = __unmap_grant_pages(map, offset, range);
359 offset += range;
360 pages -= range;
361 }
362
363 return err;
364 }
365
366 /* ------------------------------------------------------------------ */
367
gntdev_vma_open(struct vm_area_struct * vma)368 static void gntdev_vma_open(struct vm_area_struct *vma)
369 {
370 struct grant_map *map = vma->vm_private_data;
371
372 pr_debug("gntdev_vma_open %p\n", vma);
373 atomic_inc(&map->users);
374 }
375
gntdev_vma_close(struct vm_area_struct * vma)376 static void gntdev_vma_close(struct vm_area_struct *vma)
377 {
378 struct grant_map *map = vma->vm_private_data;
379
380 pr_debug("gntdev_vma_close %p\n", vma);
381 map->vma = NULL;
382 vma->vm_private_data = NULL;
383 gntdev_put_map(map);
384 }
385
386 static struct vm_operations_struct gntdev_vmops = {
387 .open = gntdev_vma_open,
388 .close = gntdev_vma_close,
389 };
390
391 /* ------------------------------------------------------------------ */
392
mn_invl_range_start(struct mmu_notifier * mn,struct mm_struct * mm,unsigned long start,unsigned long end)393 static void mn_invl_range_start(struct mmu_notifier *mn,
394 struct mm_struct *mm,
395 unsigned long start, unsigned long end)
396 {
397 struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn);
398 struct grant_map *map;
399 unsigned long mstart, mend;
400 int err;
401
402 spin_lock(&priv->lock);
403 list_for_each_entry(map, &priv->maps, next) {
404 if (!map->vma)
405 continue;
406 if (map->vma->vm_start >= end)
407 continue;
408 if (map->vma->vm_end <= start)
409 continue;
410 mstart = max(start, map->vma->vm_start);
411 mend = min(end, map->vma->vm_end);
412 pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n",
413 map->index, map->count,
414 map->vma->vm_start, map->vma->vm_end,
415 start, end, mstart, mend);
416 err = unmap_grant_pages(map,
417 (mstart - map->vma->vm_start) >> PAGE_SHIFT,
418 (mend - mstart) >> PAGE_SHIFT);
419 WARN_ON(err);
420 }
421 spin_unlock(&priv->lock);
422 }
423
mn_invl_page(struct mmu_notifier * mn,struct mm_struct * mm,unsigned long address)424 static void mn_invl_page(struct mmu_notifier *mn,
425 struct mm_struct *mm,
426 unsigned long address)
427 {
428 mn_invl_range_start(mn, mm, address, address + PAGE_SIZE);
429 }
430
mn_release(struct mmu_notifier * mn,struct mm_struct * mm)431 static void mn_release(struct mmu_notifier *mn,
432 struct mm_struct *mm)
433 {
434 struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn);
435 struct grant_map *map;
436 int err;
437
438 spin_lock(&priv->lock);
439 list_for_each_entry(map, &priv->maps, next) {
440 if (!map->vma)
441 continue;
442 pr_debug("map %d+%d (%lx %lx)\n",
443 map->index, map->count,
444 map->vma->vm_start, map->vma->vm_end);
445 err = unmap_grant_pages(map, /* offset */ 0, map->count);
446 WARN_ON(err);
447 }
448 spin_unlock(&priv->lock);
449 }
450
451 struct mmu_notifier_ops gntdev_mmu_ops = {
452 .release = mn_release,
453 .invalidate_page = mn_invl_page,
454 .invalidate_range_start = mn_invl_range_start,
455 };
456
457 /* ------------------------------------------------------------------ */
458
gntdev_open(struct inode * inode,struct file * flip)459 static int gntdev_open(struct inode *inode, struct file *flip)
460 {
461 struct gntdev_priv *priv;
462 int ret = 0;
463
464 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
465 if (!priv)
466 return -ENOMEM;
467
468 INIT_LIST_HEAD(&priv->maps);
469 spin_lock_init(&priv->lock);
470
471 if (use_ptemod) {
472 priv->mm = get_task_mm(current);
473 if (!priv->mm) {
474 kfree(priv);
475 return -ENOMEM;
476 }
477 priv->mn.ops = &gntdev_mmu_ops;
478 ret = mmu_notifier_register(&priv->mn, priv->mm);
479 mmput(priv->mm);
480 }
481
482 if (ret) {
483 kfree(priv);
484 return ret;
485 }
486
487 flip->private_data = priv;
488 pr_debug("priv %p\n", priv);
489
490 return 0;
491 }
492
gntdev_release(struct inode * inode,struct file * flip)493 static int gntdev_release(struct inode *inode, struct file *flip)
494 {
495 struct gntdev_priv *priv = flip->private_data;
496 struct grant_map *map;
497
498 pr_debug("priv %p\n", priv);
499
500 while (!list_empty(&priv->maps)) {
501 map = list_entry(priv->maps.next, struct grant_map, next);
502 list_del(&map->next);
503 gntdev_put_map(map);
504 }
505
506 if (use_ptemod)
507 mmu_notifier_unregister(&priv->mn, priv->mm);
508 kfree(priv);
509 return 0;
510 }
511
gntdev_ioctl_map_grant_ref(struct gntdev_priv * priv,struct ioctl_gntdev_map_grant_ref __user * u)512 static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv,
513 struct ioctl_gntdev_map_grant_ref __user *u)
514 {
515 struct ioctl_gntdev_map_grant_ref op;
516 struct grant_map *map;
517 int err;
518
519 if (copy_from_user(&op, u, sizeof(op)) != 0)
520 return -EFAULT;
521 pr_debug("priv %p, add %d\n", priv, op.count);
522 if (unlikely(op.count <= 0))
523 return -EINVAL;
524
525 err = -ENOMEM;
526 map = gntdev_alloc_map(priv, op.count);
527 if (!map)
528 return err;
529
530 if (unlikely(atomic_add_return(op.count, &pages_mapped) > limit)) {
531 pr_debug("can't map: over limit\n");
532 gntdev_put_map(map);
533 return err;
534 }
535
536 if (copy_from_user(map->grants, &u->refs,
537 sizeof(map->grants[0]) * op.count) != 0) {
538 gntdev_put_map(map);
539 return err;
540 }
541
542 spin_lock(&priv->lock);
543 gntdev_add_map(priv, map);
544 op.index = map->index << PAGE_SHIFT;
545 spin_unlock(&priv->lock);
546
547 if (copy_to_user(u, &op, sizeof(op)) != 0)
548 return -EFAULT;
549
550 return 0;
551 }
552
gntdev_ioctl_unmap_grant_ref(struct gntdev_priv * priv,struct ioctl_gntdev_unmap_grant_ref __user * u)553 static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv *priv,
554 struct ioctl_gntdev_unmap_grant_ref __user *u)
555 {
556 struct ioctl_gntdev_unmap_grant_ref op;
557 struct grant_map *map;
558 int err = -ENOENT;
559
560 if (copy_from_user(&op, u, sizeof(op)) != 0)
561 return -EFAULT;
562 pr_debug("priv %p, del %d+%d\n", priv, (int)op.index, (int)op.count);
563
564 spin_lock(&priv->lock);
565 map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count);
566 if (map) {
567 list_del(&map->next);
568 err = 0;
569 }
570 spin_unlock(&priv->lock);
571 if (map)
572 gntdev_put_map(map);
573 return err;
574 }
575
gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv * priv,struct ioctl_gntdev_get_offset_for_vaddr __user * u)576 static long gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv *priv,
577 struct ioctl_gntdev_get_offset_for_vaddr __user *u)
578 {
579 struct ioctl_gntdev_get_offset_for_vaddr op;
580 struct vm_area_struct *vma;
581 struct grant_map *map;
582
583 if (copy_from_user(&op, u, sizeof(op)) != 0)
584 return -EFAULT;
585 pr_debug("priv %p, offset for vaddr %lx\n", priv, (unsigned long)op.vaddr);
586
587 vma = find_vma(current->mm, op.vaddr);
588 if (!vma || vma->vm_ops != &gntdev_vmops)
589 return -EINVAL;
590
591 map = vma->vm_private_data;
592 if (!map)
593 return -EINVAL;
594
595 op.offset = map->index << PAGE_SHIFT;
596 op.count = map->count;
597
598 if (copy_to_user(u, &op, sizeof(op)) != 0)
599 return -EFAULT;
600 return 0;
601 }
602
gntdev_ioctl_notify(struct gntdev_priv * priv,void __user * u)603 static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u)
604 {
605 struct ioctl_gntdev_unmap_notify op;
606 struct grant_map *map;
607 int rc;
608 int out_flags;
609 unsigned int out_event;
610
611 if (copy_from_user(&op, u, sizeof(op)))
612 return -EFAULT;
613
614 if (op.action & ~(UNMAP_NOTIFY_CLEAR_BYTE|UNMAP_NOTIFY_SEND_EVENT))
615 return -EINVAL;
616
617 /* We need to grab a reference to the event channel we are going to use
618 * to send the notify before releasing the reference we may already have
619 * (if someone has called this ioctl twice). This is required so that
620 * it is possible to change the clear_byte part of the notification
621 * without disturbing the event channel part, which may now be the last
622 * reference to that event channel.
623 */
624 if (op.action & UNMAP_NOTIFY_SEND_EVENT) {
625 if (evtchn_get(op.event_channel_port))
626 return -EINVAL;
627 }
628
629 out_flags = op.action;
630 out_event = op.event_channel_port;
631
632 spin_lock(&priv->lock);
633
634 list_for_each_entry(map, &priv->maps, next) {
635 uint64_t begin = map->index << PAGE_SHIFT;
636 uint64_t end = (map->index + map->count) << PAGE_SHIFT;
637 if (op.index >= begin && op.index < end)
638 goto found;
639 }
640 rc = -ENOENT;
641 goto unlock_out;
642
643 found:
644 if ((op.action & UNMAP_NOTIFY_CLEAR_BYTE) &&
645 (map->flags & GNTMAP_readonly)) {
646 rc = -EINVAL;
647 goto unlock_out;
648 }
649
650 out_flags = map->notify.flags;
651 out_event = map->notify.event;
652
653 map->notify.flags = op.action;
654 map->notify.addr = op.index - (map->index << PAGE_SHIFT);
655 map->notify.event = op.event_channel_port;
656
657 rc = 0;
658
659 unlock_out:
660 spin_unlock(&priv->lock);
661
662 /* Drop the reference to the event channel we did not save in the map */
663 if (out_flags & UNMAP_NOTIFY_SEND_EVENT)
664 evtchn_put(out_event);
665
666 return rc;
667 }
668
gntdev_ioctl(struct file * flip,unsigned int cmd,unsigned long arg)669 static long gntdev_ioctl(struct file *flip,
670 unsigned int cmd, unsigned long arg)
671 {
672 struct gntdev_priv *priv = flip->private_data;
673 void __user *ptr = (void __user *)arg;
674
675 switch (cmd) {
676 case IOCTL_GNTDEV_MAP_GRANT_REF:
677 return gntdev_ioctl_map_grant_ref(priv, ptr);
678
679 case IOCTL_GNTDEV_UNMAP_GRANT_REF:
680 return gntdev_ioctl_unmap_grant_ref(priv, ptr);
681
682 case IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR:
683 return gntdev_ioctl_get_offset_for_vaddr(priv, ptr);
684
685 case IOCTL_GNTDEV_SET_UNMAP_NOTIFY:
686 return gntdev_ioctl_notify(priv, ptr);
687
688 default:
689 pr_debug("priv %p, unknown cmd %x\n", priv, cmd);
690 return -ENOIOCTLCMD;
691 }
692
693 return 0;
694 }
695
gntdev_mmap(struct file * flip,struct vm_area_struct * vma)696 static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
697 {
698 struct gntdev_priv *priv = flip->private_data;
699 int index = vma->vm_pgoff;
700 int count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
701 struct grant_map *map;
702 int i, err = -EINVAL;
703
704 if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED))
705 return -EINVAL;
706
707 pr_debug("map %d+%d at %lx (pgoff %lx)\n",
708 index, count, vma->vm_start, vma->vm_pgoff);
709
710 spin_lock(&priv->lock);
711 map = gntdev_find_map_index(priv, index, count);
712 if (!map)
713 goto unlock_out;
714 if (use_ptemod && map->vma)
715 goto unlock_out;
716 if (use_ptemod && priv->mm != vma->vm_mm) {
717 printk(KERN_WARNING "Huh? Other mm?\n");
718 goto unlock_out;
719 }
720
721 atomic_inc(&map->users);
722
723 vma->vm_ops = &gntdev_vmops;
724
725 vma->vm_flags |= VM_RESERVED|VM_DONTEXPAND;
726
727 if (use_ptemod)
728 vma->vm_flags |= VM_DONTCOPY;
729
730 vma->vm_private_data = map;
731
732 if (use_ptemod)
733 map->vma = vma;
734
735 if (map->flags) {
736 if ((vma->vm_flags & VM_WRITE) &&
737 (map->flags & GNTMAP_readonly))
738 goto out_unlock_put;
739 } else {
740 map->flags = GNTMAP_host_map;
741 if (!(vma->vm_flags & VM_WRITE))
742 map->flags |= GNTMAP_readonly;
743 }
744
745 spin_unlock(&priv->lock);
746
747 if (use_ptemod) {
748 err = apply_to_page_range(vma->vm_mm, vma->vm_start,
749 vma->vm_end - vma->vm_start,
750 find_grant_ptes, map);
751 if (err) {
752 printk(KERN_WARNING "find_grant_ptes() failure.\n");
753 goto out_put_map;
754 }
755 }
756
757 err = map_grant_pages(map);
758 if (err)
759 goto out_put_map;
760
761 if (!use_ptemod) {
762 for (i = 0; i < count; i++) {
763 err = vm_insert_page(vma, vma->vm_start + i*PAGE_SIZE,
764 map->pages[i]);
765 if (err)
766 goto out_put_map;
767 }
768 }
769
770 return 0;
771
772 unlock_out:
773 spin_unlock(&priv->lock);
774 return err;
775
776 out_unlock_put:
777 spin_unlock(&priv->lock);
778 out_put_map:
779 if (use_ptemod)
780 map->vma = NULL;
781 gntdev_put_map(map);
782 return err;
783 }
784
785 static const struct file_operations gntdev_fops = {
786 .owner = THIS_MODULE,
787 .open = gntdev_open,
788 .release = gntdev_release,
789 .mmap = gntdev_mmap,
790 .unlocked_ioctl = gntdev_ioctl
791 };
792
793 static struct miscdevice gntdev_miscdev = {
794 .minor = MISC_DYNAMIC_MINOR,
795 .name = "xen/gntdev",
796 .fops = &gntdev_fops,
797 };
798
799 /* ------------------------------------------------------------------ */
800
gntdev_init(void)801 static int __init gntdev_init(void)
802 {
803 int err;
804
805 if (!xen_domain())
806 return -ENODEV;
807
808 use_ptemod = xen_pv_domain();
809
810 err = misc_register(&gntdev_miscdev);
811 if (err != 0) {
812 printk(KERN_ERR "Could not register gntdev device\n");
813 return err;
814 }
815 return 0;
816 }
817
gntdev_exit(void)818 static void __exit gntdev_exit(void)
819 {
820 misc_deregister(&gntdev_miscdev);
821 }
822
823 module_init(gntdev_init);
824 module_exit(gntdev_exit);
825
826 /* ------------------------------------------------------------------ */
827