Root/
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 | #define populate_freeable_maps use_ptemod |
60 | |
61 | struct gntdev_priv { |
62 | /* maps with visible offsets in the file descriptor */ |
63 | struct list_head maps; |
64 | /* maps that are not visible; will be freed on munmap. |
65 | * Only populated if populate_freeable_maps == 1 */ |
66 | struct list_head freeable_maps; |
67 | /* lock protects maps and freeable_maps */ |
68 | spinlock_t lock; |
69 | struct mm_struct *mm; |
70 | struct mmu_notifier mn; |
71 | }; |
72 | |
73 | struct unmap_notify { |
74 | int flags; |
75 | /* Address relative to the start of the grant_map */ |
76 | int addr; |
77 | int event; |
78 | }; |
79 | |
80 | struct grant_map { |
81 | struct list_head next; |
82 | struct vm_area_struct *vma; |
83 | int index; |
84 | int count; |
85 | int flags; |
86 | atomic_t users; |
87 | struct unmap_notify notify; |
88 | struct ioctl_gntdev_grant_ref *grants; |
89 | struct gnttab_map_grant_ref *map_ops; |
90 | struct gnttab_unmap_grant_ref *unmap_ops; |
91 | struct gnttab_map_grant_ref *kmap_ops; |
92 | struct page **pages; |
93 | }; |
94 | |
95 | static int unmap_grant_pages(struct grant_map *map, int offset, int pages); |
96 | |
97 | /* ------------------------------------------------------------------ */ |
98 | |
99 | static void gntdev_print_maps(struct gntdev_priv *priv, |
100 | char *text, int text_index) |
101 | { |
102 | #ifdef DEBUG |
103 | struct grant_map *map; |
104 | |
105 | pr_debug("%s: maps list (priv %p)\n", __func__, priv); |
106 | list_for_each_entry(map, &priv->maps, next) |
107 | pr_debug(" index %2d, count %2d %s\n", |
108 | map->index, map->count, |
109 | map->index == text_index && text ? text : ""); |
110 | #endif |
111 | } |
112 | |
113 | static void gntdev_free_map(struct grant_map *map) |
114 | { |
115 | if (map == NULL) |
116 | return; |
117 | |
118 | if (map->pages) |
119 | free_xenballooned_pages(map->count, map->pages); |
120 | kfree(map->pages); |
121 | kfree(map->grants); |
122 | kfree(map->map_ops); |
123 | kfree(map->unmap_ops); |
124 | kfree(map->kmap_ops); |
125 | kfree(map); |
126 | } |
127 | |
128 | static struct grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count) |
129 | { |
130 | struct grant_map *add; |
131 | int i; |
132 | |
133 | add = kzalloc(sizeof(struct grant_map), GFP_KERNEL); |
134 | if (NULL == add) |
135 | return NULL; |
136 | |
137 | add->grants = kcalloc(count, sizeof(add->grants[0]), GFP_KERNEL); |
138 | add->map_ops = kcalloc(count, sizeof(add->map_ops[0]), GFP_KERNEL); |
139 | add->unmap_ops = kcalloc(count, sizeof(add->unmap_ops[0]), GFP_KERNEL); |
140 | add->kmap_ops = kcalloc(count, sizeof(add->kmap_ops[0]), GFP_KERNEL); |
141 | add->pages = kcalloc(count, sizeof(add->pages[0]), GFP_KERNEL); |
142 | if (NULL == add->grants || |
143 | NULL == add->map_ops || |
144 | NULL == add->unmap_ops || |
145 | NULL == add->kmap_ops || |
146 | NULL == add->pages) |
147 | goto err; |
148 | |
149 | if (alloc_xenballooned_pages(count, add->pages, false /* lowmem */)) |
150 | goto err; |
151 | |
152 | for (i = 0; i < count; i++) { |
153 | add->map_ops[i].handle = -1; |
154 | add->unmap_ops[i].handle = -1; |
155 | add->kmap_ops[i].handle = -1; |
156 | } |
157 | |
158 | add->index = 0; |
159 | add->count = count; |
160 | atomic_set(&add->users, 1); |
161 | |
162 | return add; |
163 | |
164 | err: |
165 | gntdev_free_map(add); |
166 | return NULL; |
167 | } |
168 | |
169 | static void gntdev_add_map(struct gntdev_priv *priv, struct grant_map *add) |
170 | { |
171 | struct grant_map *map; |
172 | |
173 | list_for_each_entry(map, &priv->maps, next) { |
174 | if (add->index + add->count < map->index) { |
175 | list_add_tail(&add->next, &map->next); |
176 | goto done; |
177 | } |
178 | add->index = map->index + map->count; |
179 | } |
180 | list_add_tail(&add->next, &priv->maps); |
181 | |
182 | done: |
183 | gntdev_print_maps(priv, "[new]", add->index); |
184 | } |
185 | |
186 | static struct grant_map *gntdev_find_map_index(struct gntdev_priv *priv, |
187 | int index, int count) |
188 | { |
189 | struct grant_map *map; |
190 | |
191 | list_for_each_entry(map, &priv->maps, next) { |
192 | if (map->index != index) |
193 | continue; |
194 | if (count && map->count != count) |
195 | continue; |
196 | return map; |
197 | } |
198 | return NULL; |
199 | } |
200 | |
201 | static void gntdev_put_map(struct gntdev_priv *priv, struct grant_map *map) |
202 | { |
203 | if (!map) |
204 | return; |
205 | |
206 | if (!atomic_dec_and_test(&map->users)) |
207 | return; |
208 | |
209 | atomic_sub(map->count, &pages_mapped); |
210 | |
211 | if (map->notify.flags & UNMAP_NOTIFY_SEND_EVENT) { |
212 | notify_remote_via_evtchn(map->notify.event); |
213 | evtchn_put(map->notify.event); |
214 | } |
215 | |
216 | if (populate_freeable_maps && priv) { |
217 | spin_lock(&priv->lock); |
218 | list_del(&map->next); |
219 | spin_unlock(&priv->lock); |
220 | } |
221 | |
222 | if (map->pages && !use_ptemod) |
223 | unmap_grant_pages(map, 0, map->count); |
224 | gntdev_free_map(map); |
225 | } |
226 | |
227 | /* ------------------------------------------------------------------ */ |
228 | |
229 | static 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 | int flags = map->flags | GNTMAP_application_map | GNTMAP_contains_pte; |
235 | u64 pte_maddr; |
236 | |
237 | BUG_ON(pgnr >= map->count); |
238 | pte_maddr = arbitrary_virt_to_machine(pte).maddr; |
239 | |
240 | gnttab_set_map_op(&map->map_ops[pgnr], pte_maddr, flags, |
241 | map->grants[pgnr].ref, |
242 | map->grants[pgnr].domid); |
243 | gnttab_set_unmap_op(&map->unmap_ops[pgnr], pte_maddr, flags, |
244 | -1 /* handle */); |
245 | return 0; |
246 | } |
247 | |
248 | static int map_grant_pages(struct grant_map *map) |
249 | { |
250 | int i, err = 0; |
251 | |
252 | if (!use_ptemod) { |
253 | /* Note: it could already be mapped */ |
254 | if (map->map_ops[0].handle != -1) |
255 | return 0; |
256 | for (i = 0; i < map->count; i++) { |
257 | unsigned long addr = (unsigned long) |
258 | pfn_to_kaddr(page_to_pfn(map->pages[i])); |
259 | gnttab_set_map_op(&map->map_ops[i], addr, map->flags, |
260 | map->grants[i].ref, |
261 | map->grants[i].domid); |
262 | gnttab_set_unmap_op(&map->unmap_ops[i], addr, |
263 | map->flags, -1 /* handle */); |
264 | } |
265 | } else { |
266 | /* |
267 | * Setup the map_ops corresponding to the pte entries pointing |
268 | * to the kernel linear addresses of the struct pages. |
269 | * These ptes are completely different from the user ptes dealt |
270 | * with find_grant_ptes. |
271 | */ |
272 | for (i = 0; i < map->count; i++) { |
273 | unsigned level; |
274 | unsigned long address = (unsigned long) |
275 | pfn_to_kaddr(page_to_pfn(map->pages[i])); |
276 | pte_t *ptep; |
277 | u64 pte_maddr = 0; |
278 | BUG_ON(PageHighMem(map->pages[i])); |
279 | |
280 | ptep = lookup_address(address, &level); |
281 | pte_maddr = arbitrary_virt_to_machine(ptep).maddr; |
282 | gnttab_set_map_op(&map->kmap_ops[i], pte_maddr, |
283 | map->flags | |
284 | GNTMAP_host_map | |
285 | GNTMAP_contains_pte, |
286 | map->grants[i].ref, |
287 | map->grants[i].domid); |
288 | } |
289 | } |
290 | |
291 | pr_debug("map %d+%d\n", map->index, map->count); |
292 | err = gnttab_map_refs(map->map_ops, use_ptemod ? map->kmap_ops : NULL, |
293 | map->pages, map->count); |
294 | if (err) |
295 | return err; |
296 | |
297 | for (i = 0; i < map->count; i++) { |
298 | if (map->map_ops[i].status) |
299 | err = -EINVAL; |
300 | else { |
301 | BUG_ON(map->map_ops[i].handle == -1); |
302 | map->unmap_ops[i].handle = map->map_ops[i].handle; |
303 | pr_debug("map handle=%d\n", map->map_ops[i].handle); |
304 | } |
305 | } |
306 | return err; |
307 | } |
308 | |
309 | static int __unmap_grant_pages(struct grant_map *map, int offset, int pages) |
310 | { |
311 | int i, err = 0; |
312 | |
313 | if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) { |
314 | int pgno = (map->notify.addr >> PAGE_SHIFT); |
315 | if (pgno >= offset && pgno < offset + pages) { |
316 | /* No need for kmap, pages are in lowmem */ |
317 | uint8_t *tmp = pfn_to_kaddr(page_to_pfn(map->pages[pgno])); |
318 | tmp[map->notify.addr & (PAGE_SIZE-1)] = 0; |
319 | map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE; |
320 | } |
321 | } |
322 | |
323 | err = gnttab_unmap_refs(map->unmap_ops + offset, |
324 | use_ptemod ? map->kmap_ops + offset : NULL, map->pages + offset, |
325 | pages); |
326 | if (err) |
327 | return err; |
328 | |
329 | for (i = 0; i < pages; i++) { |
330 | if (map->unmap_ops[offset+i].status) |
331 | err = -EINVAL; |
332 | pr_debug("unmap handle=%d st=%d\n", |
333 | map->unmap_ops[offset+i].handle, |
334 | map->unmap_ops[offset+i].status); |
335 | map->unmap_ops[offset+i].handle = -1; |
336 | } |
337 | return err; |
338 | } |
339 | |
340 | static int unmap_grant_pages(struct grant_map *map, int offset, int pages) |
341 | { |
342 | int range, err = 0; |
343 | |
344 | pr_debug("unmap %d+%d [%d+%d]\n", map->index, map->count, offset, pages); |
345 | |
346 | /* It is possible the requested range will have a "hole" where we |
347 | * already unmapped some of the grants. Only unmap valid ranges. |
348 | */ |
349 | while (pages && !err) { |
350 | while (pages && map->unmap_ops[offset].handle == -1) { |
351 | offset++; |
352 | pages--; |
353 | } |
354 | range = 0; |
355 | while (range < pages) { |
356 | if (map->unmap_ops[offset+range].handle == -1) { |
357 | range--; |
358 | break; |
359 | } |
360 | range++; |
361 | } |
362 | err = __unmap_grant_pages(map, offset, range); |
363 | offset += range; |
364 | pages -= range; |
365 | } |
366 | |
367 | return err; |
368 | } |
369 | |
370 | /* ------------------------------------------------------------------ */ |
371 | |
372 | static void gntdev_vma_open(struct vm_area_struct *vma) |
373 | { |
374 | struct grant_map *map = vma->vm_private_data; |
375 | |
376 | pr_debug("gntdev_vma_open %p\n", vma); |
377 | atomic_inc(&map->users); |
378 | } |
379 | |
380 | static void gntdev_vma_close(struct vm_area_struct *vma) |
381 | { |
382 | struct grant_map *map = vma->vm_private_data; |
383 | struct file *file = vma->vm_file; |
384 | struct gntdev_priv *priv = file->private_data; |
385 | |
386 | pr_debug("gntdev_vma_close %p\n", vma); |
387 | if (use_ptemod) { |
388 | /* It is possible that an mmu notifier could be running |
389 | * concurrently, so take priv->lock to ensure that the vma won't |
390 | * vanishing during the unmap_grant_pages call, since we will |
391 | * spin here until that completes. Such a concurrent call will |
392 | * not do any unmapping, since that has been done prior to |
393 | * closing the vma, but it may still iterate the unmap_ops list. |
394 | */ |
395 | spin_lock(&priv->lock); |
396 | map->vma = NULL; |
397 | spin_unlock(&priv->lock); |
398 | } |
399 | vma->vm_private_data = NULL; |
400 | gntdev_put_map(priv, map); |
401 | } |
402 | |
403 | static struct vm_operations_struct gntdev_vmops = { |
404 | .open = gntdev_vma_open, |
405 | .close = gntdev_vma_close, |
406 | }; |
407 | |
408 | /* ------------------------------------------------------------------ */ |
409 | |
410 | static void unmap_if_in_range(struct grant_map *map, |
411 | unsigned long start, unsigned long end) |
412 | { |
413 | unsigned long mstart, mend; |
414 | int err; |
415 | |
416 | if (!map->vma) |
417 | return; |
418 | if (map->vma->vm_start >= end) |
419 | return; |
420 | if (map->vma->vm_end <= start) |
421 | return; |
422 | mstart = max(start, map->vma->vm_start); |
423 | mend = min(end, map->vma->vm_end); |
424 | pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n", |
425 | map->index, map->count, |
426 | map->vma->vm_start, map->vma->vm_end, |
427 | start, end, mstart, mend); |
428 | err = unmap_grant_pages(map, |
429 | (mstart - map->vma->vm_start) >> PAGE_SHIFT, |
430 | (mend - mstart) >> PAGE_SHIFT); |
431 | WARN_ON(err); |
432 | } |
433 | |
434 | static void mn_invl_range_start(struct mmu_notifier *mn, |
435 | struct mm_struct *mm, |
436 | unsigned long start, unsigned long end) |
437 | { |
438 | struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn); |
439 | struct grant_map *map; |
440 | |
441 | spin_lock(&priv->lock); |
442 | list_for_each_entry(map, &priv->maps, next) { |
443 | unmap_if_in_range(map, start, end); |
444 | } |
445 | list_for_each_entry(map, &priv->freeable_maps, next) { |
446 | unmap_if_in_range(map, start, end); |
447 | } |
448 | spin_unlock(&priv->lock); |
449 | } |
450 | |
451 | static void mn_invl_page(struct mmu_notifier *mn, |
452 | struct mm_struct *mm, |
453 | unsigned long address) |
454 | { |
455 | mn_invl_range_start(mn, mm, address, address + PAGE_SIZE); |
456 | } |
457 | |
458 | static void mn_release(struct mmu_notifier *mn, |
459 | struct mm_struct *mm) |
460 | { |
461 | struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn); |
462 | struct grant_map *map; |
463 | int err; |
464 | |
465 | spin_lock(&priv->lock); |
466 | list_for_each_entry(map, &priv->maps, next) { |
467 | if (!map->vma) |
468 | continue; |
469 | pr_debug("map %d+%d (%lx %lx)\n", |
470 | map->index, map->count, |
471 | map->vma->vm_start, map->vma->vm_end); |
472 | err = unmap_grant_pages(map, /* offset */ 0, map->count); |
473 | WARN_ON(err); |
474 | } |
475 | list_for_each_entry(map, &priv->freeable_maps, next) { |
476 | if (!map->vma) |
477 | continue; |
478 | pr_debug("map %d+%d (%lx %lx)\n", |
479 | map->index, map->count, |
480 | map->vma->vm_start, map->vma->vm_end); |
481 | err = unmap_grant_pages(map, /* offset */ 0, map->count); |
482 | WARN_ON(err); |
483 | } |
484 | spin_unlock(&priv->lock); |
485 | } |
486 | |
487 | static struct mmu_notifier_ops gntdev_mmu_ops = { |
488 | .release = mn_release, |
489 | .invalidate_page = mn_invl_page, |
490 | .invalidate_range_start = mn_invl_range_start, |
491 | }; |
492 | |
493 | /* ------------------------------------------------------------------ */ |
494 | |
495 | static int gntdev_open(struct inode *inode, struct file *flip) |
496 | { |
497 | struct gntdev_priv *priv; |
498 | int ret = 0; |
499 | |
500 | priv = kzalloc(sizeof(*priv), GFP_KERNEL); |
501 | if (!priv) |
502 | return -ENOMEM; |
503 | |
504 | INIT_LIST_HEAD(&priv->maps); |
505 | INIT_LIST_HEAD(&priv->freeable_maps); |
506 | spin_lock_init(&priv->lock); |
507 | |
508 | if (use_ptemod) { |
509 | priv->mm = get_task_mm(current); |
510 | if (!priv->mm) { |
511 | kfree(priv); |
512 | return -ENOMEM; |
513 | } |
514 | priv->mn.ops = &gntdev_mmu_ops; |
515 | ret = mmu_notifier_register(&priv->mn, priv->mm); |
516 | mmput(priv->mm); |
517 | } |
518 | |
519 | if (ret) { |
520 | kfree(priv); |
521 | return ret; |
522 | } |
523 | |
524 | flip->private_data = priv; |
525 | pr_debug("priv %p\n", priv); |
526 | |
527 | return 0; |
528 | } |
529 | |
530 | static int gntdev_release(struct inode *inode, struct file *flip) |
531 | { |
532 | struct gntdev_priv *priv = flip->private_data; |
533 | struct grant_map *map; |
534 | |
535 | pr_debug("priv %p\n", priv); |
536 | |
537 | while (!list_empty(&priv->maps)) { |
538 | map = list_entry(priv->maps.next, struct grant_map, next); |
539 | list_del(&map->next); |
540 | gntdev_put_map(NULL /* already removed */, map); |
541 | } |
542 | WARN_ON(!list_empty(&priv->freeable_maps)); |
543 | |
544 | if (use_ptemod) |
545 | mmu_notifier_unregister(&priv->mn, priv->mm); |
546 | kfree(priv); |
547 | return 0; |
548 | } |
549 | |
550 | static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv, |
551 | struct ioctl_gntdev_map_grant_ref __user *u) |
552 | { |
553 | struct ioctl_gntdev_map_grant_ref op; |
554 | struct grant_map *map; |
555 | int err; |
556 | |
557 | if (copy_from_user(&op, u, sizeof(op)) != 0) |
558 | return -EFAULT; |
559 | pr_debug("priv %p, add %d\n", priv, op.count); |
560 | if (unlikely(op.count <= 0)) |
561 | return -EINVAL; |
562 | |
563 | err = -ENOMEM; |
564 | map = gntdev_alloc_map(priv, op.count); |
565 | if (!map) |
566 | return err; |
567 | |
568 | if (unlikely(atomic_add_return(op.count, &pages_mapped) > limit)) { |
569 | pr_debug("can't map: over limit\n"); |
570 | gntdev_put_map(NULL, map); |
571 | return err; |
572 | } |
573 | |
574 | if (copy_from_user(map->grants, &u->refs, |
575 | sizeof(map->grants[0]) * op.count) != 0) { |
576 | gntdev_put_map(NULL, map); |
577 | return -EFAULT; |
578 | } |
579 | |
580 | spin_lock(&priv->lock); |
581 | gntdev_add_map(priv, map); |
582 | op.index = map->index << PAGE_SHIFT; |
583 | spin_unlock(&priv->lock); |
584 | |
585 | if (copy_to_user(u, &op, sizeof(op)) != 0) |
586 | return -EFAULT; |
587 | |
588 | return 0; |
589 | } |
590 | |
591 | static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv *priv, |
592 | struct ioctl_gntdev_unmap_grant_ref __user *u) |
593 | { |
594 | struct ioctl_gntdev_unmap_grant_ref op; |
595 | struct grant_map *map; |
596 | int err = -ENOENT; |
597 | |
598 | if (copy_from_user(&op, u, sizeof(op)) != 0) |
599 | return -EFAULT; |
600 | pr_debug("priv %p, del %d+%d\n", priv, (int)op.index, (int)op.count); |
601 | |
602 | spin_lock(&priv->lock); |
603 | map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count); |
604 | if (map) { |
605 | list_del(&map->next); |
606 | if (populate_freeable_maps) |
607 | list_add_tail(&map->next, &priv->freeable_maps); |
608 | err = 0; |
609 | } |
610 | spin_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 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(¤t->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(¤t->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 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 | spin_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 | spin_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 | static long gntdev_ioctl(struct file *flip, |
716 | unsigned int cmd, unsigned long arg) |
717 | { |
718 | struct gntdev_priv *priv = flip->private_data; |
719 | void __user *ptr = (void __user *)arg; |
720 | |
721 | switch (cmd) { |
722 | case IOCTL_GNTDEV_MAP_GRANT_REF: |
723 | return gntdev_ioctl_map_grant_ref(priv, ptr); |
724 | |
725 | case IOCTL_GNTDEV_UNMAP_GRANT_REF: |
726 | return gntdev_ioctl_unmap_grant_ref(priv, ptr); |
727 | |
728 | case IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR: |
729 | return gntdev_ioctl_get_offset_for_vaddr(priv, ptr); |
730 | |
731 | case IOCTL_GNTDEV_SET_UNMAP_NOTIFY: |
732 | return gntdev_ioctl_notify(priv, ptr); |
733 | |
734 | default: |
735 | pr_debug("priv %p, unknown cmd %x\n", priv, cmd); |
736 | return -ENOIOCTLCMD; |
737 | } |
738 | |
739 | return 0; |
740 | } |
741 | |
742 | static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) |
743 | { |
744 | struct gntdev_priv *priv = flip->private_data; |
745 | int index = vma->vm_pgoff; |
746 | int count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; |
747 | struct grant_map *map; |
748 | int i, err = -EINVAL; |
749 | |
750 | if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED)) |
751 | return -EINVAL; |
752 | |
753 | pr_debug("map %d+%d at %lx (pgoff %lx)\n", |
754 | index, count, vma->vm_start, vma->vm_pgoff); |
755 | |
756 | spin_lock(&priv->lock); |
757 | map = gntdev_find_map_index(priv, index, count); |
758 | if (!map) |
759 | goto unlock_out; |
760 | if (use_ptemod && map->vma) |
761 | goto unlock_out; |
762 | if (use_ptemod && priv->mm != vma->vm_mm) { |
763 | printk(KERN_WARNING "Huh? Other mm?\n"); |
764 | goto unlock_out; |
765 | } |
766 | |
767 | atomic_inc(&map->users); |
768 | |
769 | vma->vm_ops = &gntdev_vmops; |
770 | |
771 | vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP; |
772 | |
773 | if (use_ptemod) |
774 | vma->vm_flags |= VM_DONTCOPY; |
775 | |
776 | vma->vm_private_data = map; |
777 | |
778 | if (use_ptemod) |
779 | map->vma = vma; |
780 | |
781 | if (map->flags) { |
782 | if ((vma->vm_flags & VM_WRITE) && |
783 | (map->flags & GNTMAP_readonly)) |
784 | goto out_unlock_put; |
785 | } else { |
786 | map->flags = GNTMAP_host_map; |
787 | if (!(vma->vm_flags & VM_WRITE)) |
788 | map->flags |= GNTMAP_readonly; |
789 | } |
790 | |
791 | spin_unlock(&priv->lock); |
792 | |
793 | if (use_ptemod) { |
794 | err = apply_to_page_range(vma->vm_mm, vma->vm_start, |
795 | vma->vm_end - vma->vm_start, |
796 | find_grant_ptes, map); |
797 | if (err) { |
798 | printk(KERN_WARNING "find_grant_ptes() failure.\n"); |
799 | goto out_put_map; |
800 | } |
801 | } |
802 | |
803 | err = map_grant_pages(map); |
804 | if (err) |
805 | goto out_put_map; |
806 | |
807 | if (!use_ptemod) { |
808 | for (i = 0; i < count; i++) { |
809 | err = vm_insert_page(vma, vma->vm_start + i*PAGE_SIZE, |
810 | map->pages[i]); |
811 | if (err) |
812 | goto out_put_map; |
813 | } |
814 | } |
815 | |
816 | return 0; |
817 | |
818 | unlock_out: |
819 | spin_unlock(&priv->lock); |
820 | return err; |
821 | |
822 | out_unlock_put: |
823 | spin_unlock(&priv->lock); |
824 | out_put_map: |
825 | if (use_ptemod) |
826 | map->vma = NULL; |
827 | gntdev_put_map(priv, map); |
828 | return err; |
829 | } |
830 | |
831 | static const struct file_operations gntdev_fops = { |
832 | .owner = THIS_MODULE, |
833 | .open = gntdev_open, |
834 | .release = gntdev_release, |
835 | .mmap = gntdev_mmap, |
836 | .unlocked_ioctl = gntdev_ioctl |
837 | }; |
838 | |
839 | static struct miscdevice gntdev_miscdev = { |
840 | .minor = MISC_DYNAMIC_MINOR, |
841 | .name = "xen/gntdev", |
842 | .fops = &gntdev_fops, |
843 | }; |
844 | |
845 | /* ------------------------------------------------------------------ */ |
846 | |
847 | static int __init gntdev_init(void) |
848 | { |
849 | int err; |
850 | |
851 | if (!xen_domain()) |
852 | return -ENODEV; |
853 | |
854 | use_ptemod = xen_pv_domain(); |
855 | |
856 | err = misc_register(&gntdev_miscdev); |
857 | if (err != 0) { |
858 | printk(KERN_ERR "Could not register gntdev device\n"); |
859 | return err; |
860 | } |
861 | return 0; |
862 | } |
863 | |
864 | static void __exit gntdev_exit(void) |
865 | { |
866 | misc_deregister(&gntdev_miscdev); |
867 | } |
868 | |
869 | module_init(gntdev_init); |
870 | module_exit(gntdev_exit); |
871 | |
872 | /* ------------------------------------------------------------------ */ |
873 |
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v2.6.34-rc5
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