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