blob: 1e31cdcdae1e1f088a03b766f938787bee5cc241 [file] [log] [blame]
Gerd Hoffmannab315232010-12-14 18:40:46 +00001/******************************************************************************
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
36#include <xen/xen.h>
37#include <xen/grant_table.h>
38#include <xen/gntdev.h>
39#include <asm/xen/hypervisor.h>
40#include <asm/xen/hypercall.h>
41#include <asm/xen/page.h>
42
43MODULE_LICENSE("GPL");
44MODULE_AUTHOR("Derek G. Murray <Derek.Murray@cl.cam.ac.uk>, "
45 "Gerd Hoffmann <kraxel@redhat.com>");
46MODULE_DESCRIPTION("User-space granted page access driver");
47
48static int limit = 1024;
49module_param(limit, int, 0644);
50MODULE_PARM_DESC(limit, "Maximum number of grants that may be mapped at "
51 "once by a gntdev instance");
52
53struct gntdev_priv {
54 struct list_head maps;
55 uint32_t used;
56 uint32_t limit;
57 /* lock protects maps from concurrent changes */
58 spinlock_t lock;
59 struct mm_struct *mm;
60 struct mmu_notifier mn;
61};
62
63struct grant_map {
64 struct list_head next;
65 struct gntdev_priv *priv;
66 struct vm_area_struct *vma;
67 int index;
68 int count;
69 int flags;
70 int is_mapped;
71 struct ioctl_gntdev_grant_ref *grants;
72 struct gnttab_map_grant_ref *map_ops;
73 struct gnttab_unmap_grant_ref *unmap_ops;
Stefano Stabellinia12b4eb2010-12-10 14:56:42 +000074 struct page **pages;
Gerd Hoffmannab315232010-12-14 18:40:46 +000075};
76
77/* ------------------------------------------------------------------ */
78
79static void gntdev_print_maps(struct gntdev_priv *priv,
80 char *text, int text_index)
81{
82#ifdef DEBUG
83 struct grant_map *map;
84
85 pr_debug("maps list (priv %p, usage %d/%d)\n",
86 priv, priv->used, priv->limit);
87
88 list_for_each_entry(map, &priv->maps, next)
89 pr_debug(" index %2d, count %2d %s\n",
90 map->index, map->count,
91 map->index == text_index && text ? text : "");
92#endif
93}
94
95static struct grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count)
96{
97 struct grant_map *add;
Stefano Stabellinia12b4eb2010-12-10 14:56:42 +000098 int i;
Gerd Hoffmannab315232010-12-14 18:40:46 +000099
100 add = kzalloc(sizeof(struct grant_map), GFP_KERNEL);
101 if (NULL == add)
102 return NULL;
103
104 add->grants = kzalloc(sizeof(add->grants[0]) * count, GFP_KERNEL);
105 add->map_ops = kzalloc(sizeof(add->map_ops[0]) * count, GFP_KERNEL);
106 add->unmap_ops = kzalloc(sizeof(add->unmap_ops[0]) * count, GFP_KERNEL);
Stefano Stabellinia12b4eb2010-12-10 14:56:42 +0000107 add->pages = kzalloc(sizeof(add->pages[0]) * count, GFP_KERNEL);
108 if (NULL == add->grants ||
109 NULL == add->map_ops ||
110 NULL == add->unmap_ops ||
111 NULL == add->pages)
Gerd Hoffmannab315232010-12-14 18:40:46 +0000112 goto err;
113
Stefano Stabellinia12b4eb2010-12-10 14:56:42 +0000114 for (i = 0; i < count; i++) {
115 add->pages[i] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
116 if (add->pages[i] == NULL)
117 goto err;
118 }
119
Gerd Hoffmannab315232010-12-14 18:40:46 +0000120 add->index = 0;
121 add->count = count;
122 add->priv = priv;
123
124 if (add->count + priv->used > priv->limit)
125 goto err;
126
127 return add;
128
129err:
Stefano Stabellinia12b4eb2010-12-10 14:56:42 +0000130 if (add->pages)
131 for (i = 0; i < count; i++) {
132 if (add->pages[i])
133 __free_page(add->pages[i]);
134 }
135 kfree(add->pages);
Gerd Hoffmannab315232010-12-14 18:40:46 +0000136 kfree(add->grants);
137 kfree(add->map_ops);
138 kfree(add->unmap_ops);
139 kfree(add);
140 return NULL;
141}
142
143static void gntdev_add_map(struct gntdev_priv *priv, struct grant_map *add)
144{
145 struct grant_map *map;
146
147 list_for_each_entry(map, &priv->maps, next) {
148 if (add->index + add->count < map->index) {
149 list_add_tail(&add->next, &map->next);
150 goto done;
151 }
152 add->index = map->index + map->count;
153 }
154 list_add_tail(&add->next, &priv->maps);
155
156done:
157 priv->used += add->count;
158 gntdev_print_maps(priv, "[new]", add->index);
159}
160
161static struct grant_map *gntdev_find_map_index(struct gntdev_priv *priv,
162 int index, int count)
163{
164 struct grant_map *map;
165
166 list_for_each_entry(map, &priv->maps, next) {
167 if (map->index != index)
168 continue;
169 if (map->count != count)
170 continue;
171 return map;
172 }
173 return NULL;
174}
175
176static struct grant_map *gntdev_find_map_vaddr(struct gntdev_priv *priv,
177 unsigned long vaddr)
178{
179 struct grant_map *map;
180
181 list_for_each_entry(map, &priv->maps, next) {
182 if (!map->vma)
183 continue;
184 if (vaddr < map->vma->vm_start)
185 continue;
186 if (vaddr >= map->vma->vm_end)
187 continue;
188 return map;
189 }
190 return NULL;
191}
192
193static int gntdev_del_map(struct grant_map *map)
194{
195 int i;
196
197 if (map->vma)
198 return -EBUSY;
199 for (i = 0; i < map->count; i++)
200 if (map->unmap_ops[i].handle)
201 return -EBUSY;
202
203 map->priv->used -= map->count;
204 list_del(&map->next);
205 return 0;
206}
207
208static void gntdev_free_map(struct grant_map *map)
209{
Stefano Stabellinia12b4eb2010-12-10 14:56:42 +0000210 int i;
211
Gerd Hoffmannab315232010-12-14 18:40:46 +0000212 if (!map)
213 return;
Stefano Stabellinia12b4eb2010-12-10 14:56:42 +0000214
215 if (map->pages)
216 for (i = 0; i < map->count; i++) {
217 if (map->pages[i])
218 __free_page(map->pages[i]);
219 }
220 kfree(map->pages);
Gerd Hoffmannab315232010-12-14 18:40:46 +0000221 kfree(map->grants);
222 kfree(map->map_ops);
223 kfree(map->unmap_ops);
224 kfree(map);
225}
226
227/* ------------------------------------------------------------------ */
228
229static int find_grant_ptes(pte_t *pte, pgtable_t token,
230 unsigned long addr, void *data)
231{
232 struct grant_map *map = data;
233 unsigned int pgnr = (addr - map->vma->vm_start) >> PAGE_SHIFT;
234 u64 pte_maddr;
235
236 BUG_ON(pgnr >= map->count);
Jeremy Fitzhardingeba5d1012010-12-08 10:54:32 -0800237 pte_maddr = arbitrary_virt_to_machine(pte).maddr;
238
Ian Campbell9329e762010-12-08 11:57:40 +0000239 gnttab_set_map_op(&map->map_ops[pgnr], pte_maddr,
240 GNTMAP_contains_pte | map->flags,
Gerd Hoffmannab315232010-12-14 18:40:46 +0000241 map->grants[pgnr].ref,
242 map->grants[pgnr].domid);
Ian Campbell9329e762010-12-08 11:57:40 +0000243 gnttab_set_unmap_op(&map->unmap_ops[pgnr], pte_maddr,
244 GNTMAP_contains_pte | map->flags,
Gerd Hoffmannab315232010-12-14 18:40:46 +0000245 0 /* handle */);
246 return 0;
247}
248
249static int map_grant_pages(struct grant_map *map)
250{
251 int i, err = 0;
252
253 pr_debug("map %d+%d\n", map->index, map->count);
Stefano Stabellinia12b4eb2010-12-10 14:56:42 +0000254 err = gnttab_map_refs(map->map_ops, map->pages, map->count);
Gerd Hoffmannab315232010-12-14 18:40:46 +0000255 if (err)
256 return err;
257
258 for (i = 0; i < map->count; i++) {
259 if (map->map_ops[i].status)
260 err = -EINVAL;
261 map->unmap_ops[i].handle = map->map_ops[i].handle;
262 }
263 return err;
264}
265
266static int unmap_grant_pages(struct grant_map *map, int offset, int pages)
267{
268 int i, err = 0;
269
270 pr_debug("map %d+%d [%d+%d]\n", map->index, map->count, offset, pages);
Stefano Stabellinia12b4eb2010-12-10 14:56:42 +0000271 err = gnttab_unmap_refs(map->unmap_ops + offset, map->pages, pages);
Gerd Hoffmannab315232010-12-14 18:40:46 +0000272 if (err)
273 return err;
274
275 for (i = 0; i < pages; i++) {
276 if (map->unmap_ops[offset+i].status)
277 err = -EINVAL;
278 map->unmap_ops[offset+i].handle = 0;
279 }
280 return err;
281}
282
283/* ------------------------------------------------------------------ */
284
285static void gntdev_vma_close(struct vm_area_struct *vma)
286{
287 struct grant_map *map = vma->vm_private_data;
288
289 pr_debug("close %p\n", vma);
290 map->is_mapped = 0;
291 map->vma = NULL;
292 vma->vm_private_data = NULL;
293}
294
295static int gntdev_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
296{
297 pr_debug("vaddr %p, pgoff %ld (shouldn't happen)\n",
298 vmf->virtual_address, vmf->pgoff);
299 vmf->flags = VM_FAULT_ERROR;
300 return 0;
301}
302
303static struct vm_operations_struct gntdev_vmops = {
304 .close = gntdev_vma_close,
305 .fault = gntdev_vma_fault,
306};
307
308/* ------------------------------------------------------------------ */
309
310static void mn_invl_range_start(struct mmu_notifier *mn,
311 struct mm_struct *mm,
312 unsigned long start, unsigned long end)
313{
314 struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn);
315 struct grant_map *map;
316 unsigned long mstart, mend;
317 int err;
318
319 spin_lock(&priv->lock);
320 list_for_each_entry(map, &priv->maps, next) {
321 if (!map->vma)
322 continue;
323 if (!map->is_mapped)
324 continue;
325 if (map->vma->vm_start >= end)
326 continue;
327 if (map->vma->vm_end <= start)
328 continue;
329 mstart = max(start, map->vma->vm_start);
330 mend = min(end, map->vma->vm_end);
331 pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n",
332 map->index, map->count,
333 map->vma->vm_start, map->vma->vm_end,
334 start, end, mstart, mend);
335 err = unmap_grant_pages(map,
336 (mstart - map->vma->vm_start) >> PAGE_SHIFT,
337 (mend - mstart) >> PAGE_SHIFT);
338 WARN_ON(err);
339 }
340 spin_unlock(&priv->lock);
341}
342
343static void mn_invl_page(struct mmu_notifier *mn,
344 struct mm_struct *mm,
345 unsigned long address)
346{
347 mn_invl_range_start(mn, mm, address, address + PAGE_SIZE);
348}
349
350static void mn_release(struct mmu_notifier *mn,
351 struct mm_struct *mm)
352{
353 struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn);
354 struct grant_map *map;
355 int err;
356
357 spin_lock(&priv->lock);
358 list_for_each_entry(map, &priv->maps, next) {
359 if (!map->vma)
360 continue;
361 pr_debug("map %d+%d (%lx %lx)\n",
362 map->index, map->count,
363 map->vma->vm_start, map->vma->vm_end);
364 err = unmap_grant_pages(map, /* offset */ 0, map->count);
365 WARN_ON(err);
366 }
367 spin_unlock(&priv->lock);
368}
369
370struct mmu_notifier_ops gntdev_mmu_ops = {
371 .release = mn_release,
372 .invalidate_page = mn_invl_page,
373 .invalidate_range_start = mn_invl_range_start,
374};
375
376/* ------------------------------------------------------------------ */
377
378static int gntdev_open(struct inode *inode, struct file *flip)
379{
380 struct gntdev_priv *priv;
381 int ret = 0;
382
383 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
384 if (!priv)
385 return -ENOMEM;
386
387 INIT_LIST_HEAD(&priv->maps);
388 spin_lock_init(&priv->lock);
389 priv->limit = limit;
390
391 priv->mm = get_task_mm(current);
392 if (!priv->mm) {
393 kfree(priv);
394 return -ENOMEM;
395 }
396 priv->mn.ops = &gntdev_mmu_ops;
397 ret = mmu_notifier_register(&priv->mn, priv->mm);
398 mmput(priv->mm);
399
400 if (ret) {
401 kfree(priv);
402 return ret;
403 }
404
405 flip->private_data = priv;
406 pr_debug("priv %p\n", priv);
407
408 return 0;
409}
410
411static int gntdev_release(struct inode *inode, struct file *flip)
412{
413 struct gntdev_priv *priv = flip->private_data;
414 struct grant_map *map;
415 int err;
416
417 pr_debug("priv %p\n", priv);
418
419 spin_lock(&priv->lock);
420 while (!list_empty(&priv->maps)) {
421 map = list_entry(priv->maps.next, struct grant_map, next);
422 err = gntdev_del_map(map);
423 if (WARN_ON(err))
424 gntdev_free_map(map);
425
426 }
427 spin_unlock(&priv->lock);
428
429 mmu_notifier_unregister(&priv->mn, priv->mm);
430 kfree(priv);
431 return 0;
432}
433
434static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv,
435 struct ioctl_gntdev_map_grant_ref __user *u)
436{
437 struct ioctl_gntdev_map_grant_ref op;
438 struct grant_map *map;
439 int err;
440
441 if (copy_from_user(&op, u, sizeof(op)) != 0)
442 return -EFAULT;
443 pr_debug("priv %p, add %d\n", priv, op.count);
444 if (unlikely(op.count <= 0))
445 return -EINVAL;
446 if (unlikely(op.count > priv->limit))
447 return -EINVAL;
448
449 err = -ENOMEM;
450 map = gntdev_alloc_map(priv, op.count);
451 if (!map)
452 return err;
453 if (copy_from_user(map->grants, &u->refs,
454 sizeof(map->grants[0]) * op.count) != 0) {
455 gntdev_free_map(map);
456 return err;
457 }
458
459 spin_lock(&priv->lock);
460 gntdev_add_map(priv, map);
461 op.index = map->index << PAGE_SHIFT;
462 spin_unlock(&priv->lock);
463
464 if (copy_to_user(u, &op, sizeof(op)) != 0) {
465 spin_lock(&priv->lock);
466 gntdev_del_map(map);
467 spin_unlock(&priv->lock);
468 gntdev_free_map(map);
469 return err;
470 }
471 return 0;
472}
473
474static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv *priv,
475 struct ioctl_gntdev_unmap_grant_ref __user *u)
476{
477 struct ioctl_gntdev_unmap_grant_ref op;
478 struct grant_map *map;
479 int err = -ENOENT;
480
481 if (copy_from_user(&op, u, sizeof(op)) != 0)
482 return -EFAULT;
483 pr_debug("priv %p, del %d+%d\n", priv, (int)op.index, (int)op.count);
484
485 spin_lock(&priv->lock);
486 map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count);
487 if (map)
488 err = gntdev_del_map(map);
489 spin_unlock(&priv->lock);
490 if (!err)
491 gntdev_free_map(map);
492 return err;
493}
494
495static long gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv *priv,
496 struct ioctl_gntdev_get_offset_for_vaddr __user *u)
497{
498 struct ioctl_gntdev_get_offset_for_vaddr op;
499 struct grant_map *map;
500
501 if (copy_from_user(&op, u, sizeof(op)) != 0)
502 return -EFAULT;
503 pr_debug("priv %p, offset for vaddr %lx\n", priv, (unsigned long)op.vaddr);
504
505 spin_lock(&priv->lock);
506 map = gntdev_find_map_vaddr(priv, op.vaddr);
507 if (map == NULL ||
508 map->vma->vm_start != op.vaddr) {
509 spin_unlock(&priv->lock);
510 return -EINVAL;
511 }
512 op.offset = map->index << PAGE_SHIFT;
513 op.count = map->count;
514 spin_unlock(&priv->lock);
515
516 if (copy_to_user(u, &op, sizeof(op)) != 0)
517 return -EFAULT;
518 return 0;
519}
520
521static long gntdev_ioctl_set_max_grants(struct gntdev_priv *priv,
522 struct ioctl_gntdev_set_max_grants __user *u)
523{
524 struct ioctl_gntdev_set_max_grants op;
525
526 if (copy_from_user(&op, u, sizeof(op)) != 0)
527 return -EFAULT;
528 pr_debug("priv %p, limit %d\n", priv, op.count);
529 if (op.count > limit)
530 return -E2BIG;
531
532 spin_lock(&priv->lock);
533 priv->limit = op.count;
534 spin_unlock(&priv->lock);
535 return 0;
536}
537
538static long gntdev_ioctl(struct file *flip,
539 unsigned int cmd, unsigned long arg)
540{
541 struct gntdev_priv *priv = flip->private_data;
542 void __user *ptr = (void __user *)arg;
543
544 switch (cmd) {
545 case IOCTL_GNTDEV_MAP_GRANT_REF:
546 return gntdev_ioctl_map_grant_ref(priv, ptr);
547
548 case IOCTL_GNTDEV_UNMAP_GRANT_REF:
549 return gntdev_ioctl_unmap_grant_ref(priv, ptr);
550
551 case IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR:
552 return gntdev_ioctl_get_offset_for_vaddr(priv, ptr);
553
554 case IOCTL_GNTDEV_SET_MAX_GRANTS:
555 return gntdev_ioctl_set_max_grants(priv, ptr);
556
557 default:
558 pr_debug("priv %p, unknown cmd %x\n", priv, cmd);
559 return -ENOIOCTLCMD;
560 }
561
562 return 0;
563}
564
565static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
566{
567 struct gntdev_priv *priv = flip->private_data;
568 int index = vma->vm_pgoff;
569 int count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
570 struct grant_map *map;
571 int err = -EINVAL;
572
573 if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED))
574 return -EINVAL;
575
576 pr_debug("map %d+%d at %lx (pgoff %lx)\n",
577 index, count, vma->vm_start, vma->vm_pgoff);
578
579 spin_lock(&priv->lock);
580 map = gntdev_find_map_index(priv, index, count);
581 if (!map)
582 goto unlock_out;
583 if (map->vma)
584 goto unlock_out;
585 if (priv->mm != vma->vm_mm) {
586 printk(KERN_WARNING "Huh? Other mm?\n");
587 goto unlock_out;
588 }
589
590 vma->vm_ops = &gntdev_vmops;
591
Jeremy Fitzhardinge8d3eaea2010-11-11 14:39:12 -0800592 vma->vm_flags |= VM_RESERVED|VM_DONTCOPY|VM_DONTEXPAND|VM_PFNMAP;
Gerd Hoffmannab315232010-12-14 18:40:46 +0000593
594 vma->vm_private_data = map;
595 map->vma = vma;
596
Ian Campbell9329e762010-12-08 11:57:40 +0000597 map->flags = GNTMAP_host_map | GNTMAP_application_map;
Gerd Hoffmannab315232010-12-14 18:40:46 +0000598 if (!(vma->vm_flags & VM_WRITE))
599 map->flags |= GNTMAP_readonly;
600
Daniel De Graaff0a70c82011-01-07 11:51:47 +0000601 spin_unlock(&priv->lock);
602
Gerd Hoffmannab315232010-12-14 18:40:46 +0000603 err = apply_to_page_range(vma->vm_mm, vma->vm_start,
604 vma->vm_end - vma->vm_start,
605 find_grant_ptes, map);
606 if (err) {
607 printk(KERN_WARNING "find_grant_ptes() failure.\n");
Daniel De Graaff0a70c82011-01-07 11:51:47 +0000608 return err;
Gerd Hoffmannab315232010-12-14 18:40:46 +0000609 }
610
611 err = map_grant_pages(map);
612 if (err) {
613 printk(KERN_WARNING "map_grant_pages() failure.\n");
Daniel De Graaff0a70c82011-01-07 11:51:47 +0000614 return err;
Gerd Hoffmannab315232010-12-14 18:40:46 +0000615 }
Daniel De Graaff0a70c82011-01-07 11:51:47 +0000616
Gerd Hoffmannab315232010-12-14 18:40:46 +0000617 map->is_mapped = 1;
618
Daniel De Graaff0a70c82011-01-07 11:51:47 +0000619 return 0;
620
Gerd Hoffmannab315232010-12-14 18:40:46 +0000621unlock_out:
622 spin_unlock(&priv->lock);
623 return err;
624}
625
626static const struct file_operations gntdev_fops = {
627 .owner = THIS_MODULE,
628 .open = gntdev_open,
629 .release = gntdev_release,
630 .mmap = gntdev_mmap,
631 .unlocked_ioctl = gntdev_ioctl
632};
633
634static struct miscdevice gntdev_miscdev = {
635 .minor = MISC_DYNAMIC_MINOR,
636 .name = "xen/gntdev",
637 .fops = &gntdev_fops,
638};
639
640/* ------------------------------------------------------------------ */
641
642static int __init gntdev_init(void)
643{
644 int err;
645
646 if (!xen_domain())
647 return -ENODEV;
648
649 err = misc_register(&gntdev_miscdev);
650 if (err != 0) {
651 printk(KERN_ERR "Could not register gntdev device\n");
652 return err;
653 }
654 return 0;
655}
656
657static void __exit gntdev_exit(void)
658{
659 misc_deregister(&gntdev_miscdev);
660}
661
662module_init(gntdev_init);
663module_exit(gntdev_exit);
664
665/* ------------------------------------------------------------------ */