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x86/mm/pat: Don't report PAT on CPUs that don't support it
[linux/fpc-iii.git] / drivers / xen / gntdev.c
blobf3bf8f4e2d6cef09101b53aa9f1a69563b206287
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 #define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
23
24 #include <linux/module.h>
25 #include <linux/kernel.h>
26 #include <linux/init.h>
27 #include <linux/miscdevice.h>
28 #include <linux/fs.h>
29 #include <linux/mm.h>
30 #include <linux/mman.h>
31 #include <linux/mmu_notifier.h>
32 #include <linux/types.h>
33 #include <linux/uaccess.h>
34 #include <linux/sched.h>
35 #include <linux/sched/mm.h>
36 #include <linux/spinlock.h>
37 #include <linux/slab.h>
38 #include <linux/highmem.h>
39 #include <linux/refcount.h>
40
41 #include <xen/xen.h>
42 #include <xen/grant_table.h>
43 #include <xen/balloon.h>
44 #include <xen/gntdev.h>
45 #include <xen/events.h>
46 #include <xen/page.h>
47 #include <asm/xen/hypervisor.h>
48 #include <asm/xen/hypercall.h>
49
50 MODULE_LICENSE("GPL");
51 MODULE_AUTHOR("Derek G. Murray <Derek.Murray@cl.cam.ac.uk>, "
52 "Gerd Hoffmann <kraxel@redhat.com>");
53 MODULE_DESCRIPTION("User-space granted page access driver");
54
55 static int limit = 1024*1024;
56 module_param(limit, int, 0644);
57 MODULE_PARM_DESC(limit, "Maximum number of grants that may be mapped by "
58 "the gntdev device");
59
60 static atomic_t pages_mapped = ATOMIC_INIT(0);
61
62 static int use_ptemod;
63 #define populate_freeable_maps use_ptemod
64
65 struct gntdev_priv {
66 /* maps with visible offsets in the file descriptor */
67 struct list_head maps;
68 /* maps that are not visible; will be freed on munmap.
69 * Only populated if populate_freeable_maps == 1 */
70 struct list_head freeable_maps;
71 /* lock protects maps and freeable_maps */
72 struct mutex lock;
73 struct mm_struct *mm;
74 struct mmu_notifier mn;
75 };
76
77 struct unmap_notify {
78 int flags;
79 /* Address relative to the start of the grant_map */
80 int addr;
81 int event;
82 };
83
84 struct grant_map {
85 struct list_head next;
86 struct vm_area_struct *vma;
87 int index;
88 int count;
89 int flags;
90 refcount_t users;
91 struct unmap_notify notify;
92 struct ioctl_gntdev_grant_ref *grants;
93 struct gnttab_map_grant_ref *map_ops;
94 struct gnttab_unmap_grant_ref *unmap_ops;
95 struct gnttab_map_grant_ref *kmap_ops;
96 struct gnttab_unmap_grant_ref *kunmap_ops;
97 struct page **pages;
98 unsigned long pages_vm_start;
99 };
100
101 static int unmap_grant_pages(struct grant_map *map, int offset, int pages);
102
103 /* ------------------------------------------------------------------ */
104
105 static void gntdev_print_maps(struct gntdev_priv *priv,
106 char *text, int text_index)
107 {
108 #ifdef DEBUG
109 struct grant_map *map;
110
111 pr_debug("%s: maps list (priv %p)\n", __func__, priv);
112 list_for_each_entry(map, &priv->maps, next)
113 pr_debug(" index %2d, count %2d %s\n",
114 map->index, map->count,
115 map->index == text_index && text ? text : "");
116 #endif
117 }
118
119 static void gntdev_free_map(struct grant_map *map)
120 {
121 if (map == NULL)
122 return;
123
124 if (map->pages)
125 gnttab_free_pages(map->count, map->pages);
126 kfree(map->pages);
127 kfree(map->grants);
128 kfree(map->map_ops);
129 kfree(map->unmap_ops);
130 kfree(map->kmap_ops);
131 kfree(map->kunmap_ops);
132 kfree(map);
133 }
134
135 static struct grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count)
136 {
137 struct grant_map *add;
138 int i;
139
140 add = kzalloc(sizeof(struct grant_map), GFP_KERNEL);
141 if (NULL == add)
142 return NULL;
143
144 add->grants = kcalloc(count, sizeof(add->grants[0]), GFP_KERNEL);
145 add->map_ops = kcalloc(count, sizeof(add->map_ops[0]), GFP_KERNEL);
146 add->unmap_ops = kcalloc(count, sizeof(add->unmap_ops[0]), GFP_KERNEL);
147 add->kmap_ops = kcalloc(count, sizeof(add->kmap_ops[0]), GFP_KERNEL);
148 add->kunmap_ops = kcalloc(count, sizeof(add->kunmap_ops[0]), GFP_KERNEL);
149 add->pages = kcalloc(count, sizeof(add->pages[0]), GFP_KERNEL);
150 if (NULL == add->grants ||
151 NULL == add->map_ops ||
152 NULL == add->unmap_ops ||
153 NULL == add->kmap_ops ||
154 NULL == add->kunmap_ops ||
155 NULL == add->pages)
156 goto err;
157
158 if (gnttab_alloc_pages(count, add->pages))
159 goto err;
160
161 for (i = 0; i < count; i++) {
162 add->map_ops[i].handle = -1;
163 add->unmap_ops[i].handle = -1;
164 add->kmap_ops[i].handle = -1;
165 add->kunmap_ops[i].handle = -1;
166 }
167
168 add->index = 0;
169 add->count = count;
170 refcount_set(&add->users, 1);
171
172 return add;
173
174 err:
175 gntdev_free_map(add);
176 return NULL;
177 }
178
179 static void gntdev_add_map(struct gntdev_priv *priv, struct grant_map *add)
180 {
181 struct grant_map *map;
182
183 list_for_each_entry(map, &priv->maps, next) {
184 if (add->index + add->count < map->index) {
185 list_add_tail(&add->next, &map->next);
186 goto done;
187 }
188 add->index = map->index + map->count;
189 }
190 list_add_tail(&add->next, &priv->maps);
191
192 done:
193 gntdev_print_maps(priv, "[new]", add->index);
194 }
195
196 static struct grant_map *gntdev_find_map_index(struct gntdev_priv *priv,
197 int index, int count)
198 {
199 struct grant_map *map;
200
201 list_for_each_entry(map, &priv->maps, next) {
202 if (map->index != index)
203 continue;
204 if (count && map->count != count)
205 continue;
206 return map;
207 }
208 return NULL;
209 }
210
211 static void gntdev_put_map(struct gntdev_priv *priv, struct grant_map *map)
212 {
213 if (!map)
214 return;
215
216 if (!refcount_dec_and_test(&map->users))
217 return;
218
219 atomic_sub(map->count, &pages_mapped);
220
221 if (map->notify.flags & UNMAP_NOTIFY_SEND_EVENT) {
222 notify_remote_via_evtchn(map->notify.event);
223 evtchn_put(map->notify.event);
224 }
225
226 if (populate_freeable_maps && priv) {
227 mutex_lock(&priv->lock);
228 list_del(&map->next);
229 mutex_unlock(&priv->lock);
230 }
231
232 if (map->pages && !use_ptemod)
233 unmap_grant_pages(map, 0, map->count);
234 gntdev_free_map(map);
235 }
236
237 /* ------------------------------------------------------------------ */
238
239 static int find_grant_ptes(pte_t *pte, pgtable_t token,
240 unsigned long addr, void *data)
241 {
242 struct grant_map *map = data;
243 unsigned int pgnr = (addr - map->vma->vm_start) >> PAGE_SHIFT;
244 int flags = map->flags | GNTMAP_application_map | GNTMAP_contains_pte;
245 u64 pte_maddr;
246
247 BUG_ON(pgnr >= map->count);
248 pte_maddr = arbitrary_virt_to_machine(pte).maddr;
249
250 /*
251 * Set the PTE as special to force get_user_pages_fast() fall
252 * back to the slow path. If this is not supported as part of
253 * the grant map, it will be done afterwards.
254 */
255 if (xen_feature(XENFEAT_gnttab_map_avail_bits))
256 flags |= (1 << _GNTMAP_guest_avail0);
257
258 gnttab_set_map_op(&map->map_ops[pgnr], pte_maddr, flags,
259 map->grants[pgnr].ref,
260 map->grants[pgnr].domid);
261 gnttab_set_unmap_op(&map->unmap_ops[pgnr], pte_maddr, flags,
262 -1 /* handle */);
263 return 0;
264 }
265
266 #ifdef CONFIG_X86
267 static int set_grant_ptes_as_special(pte_t *pte, pgtable_t token,
268 unsigned long addr, void *data)
269 {
270 set_pte_at(current->mm, addr, pte, pte_mkspecial(*pte));
271 return 0;
272 }
273 #endif
274
275 static int map_grant_pages(struct grant_map *map)
276 {
277 int i, err = 0;
278
279 if (!use_ptemod) {
280 /* Note: it could already be mapped */
281 if (map->map_ops[0].handle != -1)
282 return 0;
283 for (i = 0; i < map->count; i++) {
284 unsigned long addr = (unsigned long)
285 pfn_to_kaddr(page_to_pfn(map->pages[i]));
286 gnttab_set_map_op(&map->map_ops[i], addr, map->flags,
287 map->grants[i].ref,
288 map->grants[i].domid);
289 gnttab_set_unmap_op(&map->unmap_ops[i], addr,
290 map->flags, -1 /* handle */);
291 }
292 } else {
293 /*
294 * Setup the map_ops corresponding to the pte entries pointing
295 * to the kernel linear addresses of the struct pages.
296 * These ptes are completely different from the user ptes dealt
297 * with find_grant_ptes.
298 */
299 for (i = 0; i < map->count; i++) {
300 unsigned long address = (unsigned long)
301 pfn_to_kaddr(page_to_pfn(map->pages[i]));
302 BUG_ON(PageHighMem(map->pages[i]));
303
304 gnttab_set_map_op(&map->kmap_ops[i], address,
305 map->flags | GNTMAP_host_map,
306 map->grants[i].ref,
307 map->grants[i].domid);
308 gnttab_set_unmap_op(&map->kunmap_ops[i], address,
309 map->flags | GNTMAP_host_map, -1);
310 }
311 }
312
313 pr_debug("map %d+%d\n", map->index, map->count);
314 err = gnttab_map_refs(map->map_ops, use_ptemod ? map->kmap_ops : NULL,
315 map->pages, map->count);
316 if (err)
317 return err;
318
319 for (i = 0; i < map->count; i++) {
320 if (map->map_ops[i].status) {
321 err = -EINVAL;
322 continue;
323 }
324
325 map->unmap_ops[i].handle = map->map_ops[i].handle;
326 if (use_ptemod)
327 map->kunmap_ops[i].handle = map->kmap_ops[i].handle;
328 }
329 return err;
330 }
331
332 static int __unmap_grant_pages(struct grant_map *map, int offset, int pages)
333 {
334 int i, err = 0;
335 struct gntab_unmap_queue_data unmap_data;
336
337 if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) {
338 int pgno = (map->notify.addr >> PAGE_SHIFT);
339 if (pgno >= offset && pgno < offset + pages) {
340 /* No need for kmap, pages are in lowmem */
341 uint8_t *tmp = pfn_to_kaddr(page_to_pfn(map->pages[pgno]));
342 tmp[map->notify.addr & (PAGE_SIZE-1)] = 0;
343 map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE;
344 }
345 }
346
347 unmap_data.unmap_ops = map->unmap_ops + offset;
348 unmap_data.kunmap_ops = use_ptemod ? map->kunmap_ops + offset : NULL;
349 unmap_data.pages = map->pages + offset;
350 unmap_data.count = pages;
351
352 err = gnttab_unmap_refs_sync(&unmap_data);
353 if (err)
354 return err;
355
356 for (i = 0; i < pages; i++) {
357 if (map->unmap_ops[offset+i].status)
358 err = -EINVAL;
359 pr_debug("unmap handle=%d st=%d\n",
360 map->unmap_ops[offset+i].handle,
361 map->unmap_ops[offset+i].status);
362 map->unmap_ops[offset+i].handle = -1;
363 }
364 return err;
365 }
366
367 static int unmap_grant_pages(struct grant_map *map, int offset, int pages)
368 {
369 int range, err = 0;
370
371 pr_debug("unmap %d+%d [%d+%d]\n", map->index, map->count, offset, pages);
372
373 /* It is possible the requested range will have a "hole" where we
374 * already unmapped some of the grants. Only unmap valid ranges.
375 */
376 while (pages && !err) {
377 while (pages && map->unmap_ops[offset].handle == -1) {
378 offset++;
379 pages--;
380 }
381 range = 0;
382 while (range < pages) {
383 if (map->unmap_ops[offset+range].handle == -1) {
384 range--;
385 break;
386 }
387 range++;
388 }
389 err = __unmap_grant_pages(map, offset, range);
390 offset += range;
391 pages -= range;
392 }
393
394 return err;
395 }
396
397 /* ------------------------------------------------------------------ */
398
399 static void gntdev_vma_open(struct vm_area_struct *vma)
400 {
401 struct grant_map *map = vma->vm_private_data;
402
403 pr_debug("gntdev_vma_open %p\n", vma);
404 refcount_inc(&map->users);
405 }
406
407 static void gntdev_vma_close(struct vm_area_struct *vma)
408 {
409 struct grant_map *map = vma->vm_private_data;
410 struct file *file = vma->vm_file;
411 struct gntdev_priv *priv = file->private_data;
412
413 pr_debug("gntdev_vma_close %p\n", vma);
414 if (use_ptemod) {
415 /* It is possible that an mmu notifier could be running
416 * concurrently, so take priv->lock to ensure that the vma won't
417 * vanishing during the unmap_grant_pages call, since we will
418 * spin here until that completes. Such a concurrent call will
419 * not do any unmapping, since that has been done prior to
420 * closing the vma, but it may still iterate the unmap_ops list.
421 */
422 mutex_lock(&priv->lock);
423 map->vma = NULL;
424 mutex_unlock(&priv->lock);
425 }
426 vma->vm_private_data = NULL;
427 gntdev_put_map(priv, map);
428 }
429
430 static struct page *gntdev_vma_find_special_page(struct vm_area_struct *vma,
431 unsigned long addr)
432 {
433 struct grant_map *map = vma->vm_private_data;
434
435 return map->pages[(addr - map->pages_vm_start) >> PAGE_SHIFT];
436 }
437
438 static const struct vm_operations_struct gntdev_vmops = {
439 .open = gntdev_vma_open,
440 .close = gntdev_vma_close,
441 .find_special_page = gntdev_vma_find_special_page,
442 };
443
444 /* ------------------------------------------------------------------ */
445
446 static void unmap_if_in_range(struct grant_map *map,
447 unsigned long start, unsigned long end)
448 {
449 unsigned long mstart, mend;
450 int err;
451
452 if (!map->vma)
453 return;
454 if (map->vma->vm_start >= end)
455 return;
456 if (map->vma->vm_end <= start)
457 return;
458 mstart = max(start, map->vma->vm_start);
459 mend = min(end, map->vma->vm_end);
460 pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n",
461 map->index, map->count,
462 map->vma->vm_start, map->vma->vm_end,
463 start, end, mstart, mend);
464 err = unmap_grant_pages(map,
465 (mstart - map->vma->vm_start) >> PAGE_SHIFT,
466 (mend - mstart) >> PAGE_SHIFT);
467 WARN_ON(err);
468 }
469
470 static void mn_invl_range_start(struct mmu_notifier *mn,
471 struct mm_struct *mm,
472 unsigned long start, unsigned long end)
473 {
474 struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn);
475 struct grant_map *map;
476
477 mutex_lock(&priv->lock);
478 list_for_each_entry(map, &priv->maps, next) {
479 unmap_if_in_range(map, start, end);
480 }
481 list_for_each_entry(map, &priv->freeable_maps, next) {
482 unmap_if_in_range(map, start, end);
483 }
484 mutex_unlock(&priv->lock);
485 }
486
487 static void mn_invl_page(struct mmu_notifier *mn,
488 struct mm_struct *mm,
489 unsigned long address)
490 {
491 mn_invl_range_start(mn, mm, address, address + PAGE_SIZE);
492 }
493
494 static void mn_release(struct mmu_notifier *mn,
495 struct mm_struct *mm)
496 {
497 struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn);
498 struct grant_map *map;
499 int err;
500
501 mutex_lock(&priv->lock);
502 list_for_each_entry(map, &priv->maps, next) {
503 if (!map->vma)
504 continue;
505 pr_debug("map %d+%d (%lx %lx)\n",
506 map->index, map->count,
507 map->vma->vm_start, map->vma->vm_end);
508 err = unmap_grant_pages(map, /* offset */ 0, map->count);
509 WARN_ON(err);
510 }
511 list_for_each_entry(map, &priv->freeable_maps, next) {
512 if (!map->vma)
513 continue;
514 pr_debug("map %d+%d (%lx %lx)\n",
515 map->index, map->count,
516 map->vma->vm_start, map->vma->vm_end);
517 err = unmap_grant_pages(map, /* offset */ 0, map->count);
518 WARN_ON(err);
519 }
520 mutex_unlock(&priv->lock);
521 }
522
523 static const struct mmu_notifier_ops gntdev_mmu_ops = {
524 .release = mn_release,
525 .invalidate_page = mn_invl_page,
526 .invalidate_range_start = mn_invl_range_start,
527 };
528
529 /* ------------------------------------------------------------------ */
530
531 static int gntdev_open(struct inode *inode, struct file *flip)
532 {
533 struct gntdev_priv *priv;
534 int ret = 0;
535
536 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
537 if (!priv)
538 return -ENOMEM;
539
540 INIT_LIST_HEAD(&priv->maps);
541 INIT_LIST_HEAD(&priv->freeable_maps);
542 mutex_init(&priv->lock);
543
544 if (use_ptemod) {
545 priv->mm = get_task_mm(current);
546 if (!priv->mm) {
547 kfree(priv);
548 return -ENOMEM;
549 }
550 priv->mn.ops = &gntdev_mmu_ops;
551 ret = mmu_notifier_register(&priv->mn, priv->mm);
552 mmput(priv->mm);
553 }
554
555 if (ret) {
556 kfree(priv);
557 return ret;
558 }
559
560 flip->private_data = priv;
561 pr_debug("priv %p\n", priv);
562
563 return 0;
564 }
565
566 static int gntdev_release(struct inode *inode, struct file *flip)
567 {
568 struct gntdev_priv *priv = flip->private_data;
569 struct grant_map *map;
570
571 pr_debug("priv %p\n", priv);
572
573 mutex_lock(&priv->lock);
574 while (!list_empty(&priv->maps)) {
575 map = list_entry(priv->maps.next, struct grant_map, next);
576 list_del(&map->next);
577 gntdev_put_map(NULL /* already removed */, map);
578 }
579 WARN_ON(!list_empty(&priv->freeable_maps));
580 mutex_unlock(&priv->lock);
581
582 if (use_ptemod)
583 mmu_notifier_unregister(&priv->mn, priv->mm);
584 kfree(priv);
585 return 0;
586 }
587
588 static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv,
589 struct ioctl_gntdev_map_grant_ref __user *u)
590 {
591 struct ioctl_gntdev_map_grant_ref op;
592 struct grant_map *map;
593 int err;
594
595 if (copy_from_user(&op, u, sizeof(op)) != 0)
596 return -EFAULT;
597 pr_debug("priv %p, add %d\n", priv, op.count);
598 if (unlikely(op.count <= 0))
599 return -EINVAL;
600
601 err = -ENOMEM;
602 map = gntdev_alloc_map(priv, op.count);
603 if (!map)
604 return err;
605
606 if (unlikely(atomic_add_return(op.count, &pages_mapped) > limit)) {
607 pr_debug("can't map: over limit\n");
608 gntdev_put_map(NULL, map);
609 return err;
610 }
611
612 if (copy_from_user(map->grants, &u->refs,
613 sizeof(map->grants[0]) * op.count) != 0) {
614 gntdev_put_map(NULL, map);
615 return -EFAULT;
616 }
617
618 mutex_lock(&priv->lock);
619 gntdev_add_map(priv, map);
620 op.index = map->index << PAGE_SHIFT;
621 mutex_unlock(&priv->lock);
622
623 if (copy_to_user(u, &op, sizeof(op)) != 0)
624 return -EFAULT;
625
626 return 0;
627 }
628
629 static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv *priv,
630 struct ioctl_gntdev_unmap_grant_ref __user *u)
631 {
632 struct ioctl_gntdev_unmap_grant_ref op;
633 struct grant_map *map;
634 int err = -ENOENT;
635
636 if (copy_from_user(&op, u, sizeof(op)) != 0)
637 return -EFAULT;
638 pr_debug("priv %p, del %d+%d\n", priv, (int)op.index, (int)op.count);
639
640 mutex_lock(&priv->lock);
641 map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count);
642 if (map) {
643 list_del(&map->next);
644 if (populate_freeable_maps)
645 list_add_tail(&map->next, &priv->freeable_maps);
646 err = 0;
647 }
648 mutex_unlock(&priv->lock);
649 if (map)
650 gntdev_put_map(priv, map);
651 return err;
652 }
653
654 static long gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv *priv,
655 struct ioctl_gntdev_get_offset_for_vaddr __user *u)
656 {
657 struct ioctl_gntdev_get_offset_for_vaddr op;
658 struct vm_area_struct *vma;
659 struct grant_map *map;
660 int rv = -EINVAL;
661
662 if (copy_from_user(&op, u, sizeof(op)) != 0)
663 return -EFAULT;
664 pr_debug("priv %p, offset for vaddr %lx\n", priv, (unsigned long)op.vaddr);
665
666 down_read(&current->mm->mmap_sem);
667 vma = find_vma(current->mm, op.vaddr);
668 if (!vma || vma->vm_ops != &gntdev_vmops)
669 goto out_unlock;
670
671 map = vma->vm_private_data;
672 if (!map)
673 goto out_unlock;
674
675 op.offset = map->index << PAGE_SHIFT;
676 op.count = map->count;
677 rv = 0;
678
679 out_unlock:
680 up_read(&current->mm->mmap_sem);
681
682 if (rv == 0 && copy_to_user(u, &op, sizeof(op)) != 0)
683 return -EFAULT;
684 return rv;
685 }
686
687 static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u)
688 {
689 struct ioctl_gntdev_unmap_notify op;
690 struct grant_map *map;
691 int rc;
692 int out_flags;
693 unsigned int out_event;
694
695 if (copy_from_user(&op, u, sizeof(op)))
696 return -EFAULT;
697
698 if (op.action & ~(UNMAP_NOTIFY_CLEAR_BYTE|UNMAP_NOTIFY_SEND_EVENT))
699 return -EINVAL;
700
701 /* We need to grab a reference to the event channel we are going to use
702 * to send the notify before releasing the reference we may already have
703 * (if someone has called this ioctl twice). This is required so that
704 * it is possible to change the clear_byte part of the notification
705 * without disturbing the event channel part, which may now be the last
706 * reference to that event channel.
707 */
708 if (op.action & UNMAP_NOTIFY_SEND_EVENT) {
709 if (evtchn_get(op.event_channel_port))
710 return -EINVAL;
711 }
712
713 out_flags = op.action;
714 out_event = op.event_channel_port;
715
716 mutex_lock(&priv->lock);
717
718 list_for_each_entry(map, &priv->maps, next) {
719 uint64_t begin = map->index << PAGE_SHIFT;
720 uint64_t end = (map->index + map->count) << PAGE_SHIFT;
721 if (op.index >= begin && op.index < end)
722 goto found;
723 }
724 rc = -ENOENT;
725 goto unlock_out;
726
727 found:
728 if ((op.action & UNMAP_NOTIFY_CLEAR_BYTE) &&
729 (map->flags & GNTMAP_readonly)) {
730 rc = -EINVAL;
731 goto unlock_out;
732 }
733
734 out_flags = map->notify.flags;
735 out_event = map->notify.event;
736
737 map->notify.flags = op.action;
738 map->notify.addr = op.index - (map->index << PAGE_SHIFT);
739 map->notify.event = op.event_channel_port;
740
741 rc = 0;
742
743 unlock_out:
744 mutex_unlock(&priv->lock);
745
746 /* Drop the reference to the event channel we did not save in the map */
747 if (out_flags & UNMAP_NOTIFY_SEND_EVENT)
748 evtchn_put(out_event);
749
750 return rc;
751 }
752
753 #define GNTDEV_COPY_BATCH 16
754
755 struct gntdev_copy_batch {
756 struct gnttab_copy ops[GNTDEV_COPY_BATCH];
757 struct page *pages[GNTDEV_COPY_BATCH];
758 s16 __user *status[GNTDEV_COPY_BATCH];
759 unsigned int nr_ops;
760 unsigned int nr_pages;
761 };
762
763 static int gntdev_get_page(struct gntdev_copy_batch *batch, void __user *virt,
764 bool writeable, unsigned long *gfn)
765 {
766 unsigned long addr = (unsigned long)virt;
767 struct page *page;
768 unsigned long xen_pfn;
769 int ret;
770
771 ret = get_user_pages_fast(addr, 1, writeable, &page);
772 if (ret < 0)
773 return ret;
774
775 batch->pages[batch->nr_pages++] = page;
776
777 xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(addr & ~PAGE_MASK);
778 *gfn = pfn_to_gfn(xen_pfn);
779
780 return 0;
781 }
782
783 static void gntdev_put_pages(struct gntdev_copy_batch *batch)
784 {
785 unsigned int i;
786
787 for (i = 0; i < batch->nr_pages; i++)
788 put_page(batch->pages[i]);
789 batch->nr_pages = 0;
790 }
791
792 static int gntdev_copy(struct gntdev_copy_batch *batch)
793 {
794 unsigned int i;
795
796 gnttab_batch_copy(batch->ops, batch->nr_ops);
797 gntdev_put_pages(batch);
798
799 /*
800 * For each completed op, update the status if the op failed
801 * and all previous ops for the segment were successful.
802 */
803 for (i = 0; i < batch->nr_ops; i++) {
804 s16 status = batch->ops[i].status;
805 s16 old_status;
806
807 if (status == GNTST_okay)
808 continue;
809
810 if (__get_user(old_status, batch->status[i]))
811 return -EFAULT;
812
813 if (old_status != GNTST_okay)
814 continue;
815
816 if (__put_user(status, batch->status[i]))
817 return -EFAULT;
818 }
819
820 batch->nr_ops = 0;
821 return 0;
822 }
823
824 static int gntdev_grant_copy_seg(struct gntdev_copy_batch *batch,
825 struct gntdev_grant_copy_segment *seg,
826 s16 __user *status)
827 {
828 uint16_t copied = 0;
829
830 /*
831 * Disallow local -> local copies since there is only space in
832 * batch->pages for one page per-op and this would be a very
833 * expensive memcpy().
834 */
835 if (!(seg->flags & (GNTCOPY_source_gref | GNTCOPY_dest_gref)))
836 return -EINVAL;
837
838 /* Can't cross page if source/dest is a grant ref. */
839 if (seg->flags & GNTCOPY_source_gref) {
840 if (seg->source.foreign.offset + seg->len > XEN_PAGE_SIZE)
841 return -EINVAL;
842 }
843 if (seg->flags & GNTCOPY_dest_gref) {
844 if (seg->dest.foreign.offset + seg->len > XEN_PAGE_SIZE)
845 return -EINVAL;
846 }
847
848 if (put_user(GNTST_okay, status))
849 return -EFAULT;
850
851 while (copied < seg->len) {
852 struct gnttab_copy *op;
853 void __user *virt;
854 size_t len, off;
855 unsigned long gfn;
856 int ret;
857
858 if (batch->nr_ops >= GNTDEV_COPY_BATCH) {
859 ret = gntdev_copy(batch);
860 if (ret < 0)
861 return ret;
862 }
863
864 len = seg->len - copied;
865
866 op = &batch->ops[batch->nr_ops];
867 op->flags = 0;
868
869 if (seg->flags & GNTCOPY_source_gref) {
870 op->source.u.ref = seg->source.foreign.ref;
871 op->source.domid = seg->source.foreign.domid;
872 op->source.offset = seg->source.foreign.offset + copied;
873 op->flags |= GNTCOPY_source_gref;
874 } else {
875 virt = seg->source.virt + copied;
876 off = (unsigned long)virt & ~XEN_PAGE_MASK;
877 len = min(len, (size_t)XEN_PAGE_SIZE - off);
878
879 ret = gntdev_get_page(batch, virt, false, &gfn);
880 if (ret < 0)
881 return ret;
882
883 op->source.u.gmfn = gfn;
884 op->source.domid = DOMID_SELF;
885 op->source.offset = off;
886 }
887
888 if (seg->flags & GNTCOPY_dest_gref) {
889 op->dest.u.ref = seg->dest.foreign.ref;
890 op->dest.domid = seg->dest.foreign.domid;
891 op->dest.offset = seg->dest.foreign.offset + copied;
892 op->flags |= GNTCOPY_dest_gref;
893 } else {
894 virt = seg->dest.virt + copied;
895 off = (unsigned long)virt & ~XEN_PAGE_MASK;
896 len = min(len, (size_t)XEN_PAGE_SIZE - off);
897
898 ret = gntdev_get_page(batch, virt, true, &gfn);
899 if (ret < 0)
900 return ret;
901
902 op->dest.u.gmfn = gfn;
903 op->dest.domid = DOMID_SELF;
904 op->dest.offset = off;
905 }
906
907 op->len = len;
908 copied += len;
909
910 batch->status[batch->nr_ops] = status;
911 batch->nr_ops++;
912 }
913
914 return 0;
915 }
916
917 static long gntdev_ioctl_grant_copy(struct gntdev_priv *priv, void __user *u)
918 {
919 struct ioctl_gntdev_grant_copy copy;
920 struct gntdev_copy_batch batch;
921 unsigned int i;
922 int ret = 0;
923
924 if (copy_from_user(&copy, u, sizeof(copy)))
925 return -EFAULT;
926
927 batch.nr_ops = 0;
928 batch.nr_pages = 0;
929
930 for (i = 0; i < copy.count; i++) {
931 struct gntdev_grant_copy_segment seg;
932
933 if (copy_from_user(&seg, &copy.segments[i], sizeof(seg))) {
934 ret = -EFAULT;
935 goto out;
936 }
937
938 ret = gntdev_grant_copy_seg(&batch, &seg, &copy.segments[i].status);
939 if (ret < 0)
940 goto out;
941
942 cond_resched();
943 }
944 if (batch.nr_ops)
945 ret = gntdev_copy(&batch);
946 return ret;
947
948 out:
949 gntdev_put_pages(&batch);
950 return ret;
951 }
952
953 static long gntdev_ioctl(struct file *flip,
954 unsigned int cmd, unsigned long arg)
955 {
956 struct gntdev_priv *priv = flip->private_data;
957 void __user *ptr = (void __user *)arg;
958
959 switch (cmd) {
960 case IOCTL_GNTDEV_MAP_GRANT_REF:
961 return gntdev_ioctl_map_grant_ref(priv, ptr);
962
963 case IOCTL_GNTDEV_UNMAP_GRANT_REF:
964 return gntdev_ioctl_unmap_grant_ref(priv, ptr);
965
966 case IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR:
967 return gntdev_ioctl_get_offset_for_vaddr(priv, ptr);
968
969 case IOCTL_GNTDEV_SET_UNMAP_NOTIFY:
970 return gntdev_ioctl_notify(priv, ptr);
971
972 case IOCTL_GNTDEV_GRANT_COPY:
973 return gntdev_ioctl_grant_copy(priv, ptr);
974
975 default:
976 pr_debug("priv %p, unknown cmd %x\n", priv, cmd);
977 return -ENOIOCTLCMD;
978 }
979
980 return 0;
981 }
982
983 static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
984 {
985 struct gntdev_priv *priv = flip->private_data;
986 int index = vma->vm_pgoff;
987 int count = vma_pages(vma);
988 struct grant_map *map;
989 int i, err = -EINVAL;
990
991 if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED))
992 return -EINVAL;
993
994 pr_debug("map %d+%d at %lx (pgoff %lx)\n",
995 index, count, vma->vm_start, vma->vm_pgoff);
996
997 mutex_lock(&priv->lock);
998 map = gntdev_find_map_index(priv, index, count);
999 if (!map)
1000 goto unlock_out;
1001 if (use_ptemod && map->vma)
1002 goto unlock_out;
1003 if (use_ptemod && priv->mm != vma->vm_mm) {
1004 pr_warn("Huh? Other mm?\n");
1005 goto unlock_out;
1006 }
1007
1008 refcount_inc(&map->users);
1009
1010 vma->vm_ops = &gntdev_vmops;
1011
1012 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP | VM_MIXEDMAP;
1013
1014 if (use_ptemod)
1015 vma->vm_flags |= VM_DONTCOPY;
1016
1017 vma->vm_private_data = map;
1018
1019 if (use_ptemod)
1020 map->vma = vma;
1021
1022 if (map->flags) {
1023 if ((vma->vm_flags & VM_WRITE) &&
1024 (map->flags & GNTMAP_readonly))
1025 goto out_unlock_put;
1026 } else {
1027 map->flags = GNTMAP_host_map;
1028 if (!(vma->vm_flags & VM_WRITE))
1029 map->flags |= GNTMAP_readonly;
1030 }
1031
1032 mutex_unlock(&priv->lock);
1033
1034 if (use_ptemod) {
1035 err = apply_to_page_range(vma->vm_mm, vma->vm_start,
1036 vma->vm_end - vma->vm_start,
1037 find_grant_ptes, map);
1038 if (err) {
1039 pr_warn("find_grant_ptes() failure.\n");
1040 goto out_put_map;
1041 }
1042 }
1043
1044 err = map_grant_pages(map);
1045 if (err)
1046 goto out_put_map;
1047
1048 if (!use_ptemod) {
1049 for (i = 0; i < count; i++) {
1050 err = vm_insert_page(vma, vma->vm_start + i*PAGE_SIZE,
1051 map->pages[i]);
1052 if (err)
1053 goto out_put_map;
1054 }
1055 } else {
1056 #ifdef CONFIG_X86
1057 /*
1058 * If the PTEs were not made special by the grant map
1059 * hypercall, do so here.
1060 *
1061 * This is racy since the mapping is already visible
1062 * to userspace but userspace should be well-behaved
1063 * enough to not touch it until the mmap() call
1064 * returns.
1065 */
1066 if (!xen_feature(XENFEAT_gnttab_map_avail_bits)) {
1067 apply_to_page_range(vma->vm_mm, vma->vm_start,
1068 vma->vm_end - vma->vm_start,
1069 set_grant_ptes_as_special, NULL);
1070 }
1071 #endif
1072 map->pages_vm_start = vma->vm_start;
1073 }
1074
1075 return 0;
1076
1077 unlock_out:
1078 mutex_unlock(&priv->lock);
1079 return err;
1080
1081 out_unlock_put:
1082 mutex_unlock(&priv->lock);
1083 out_put_map:
1084 if (use_ptemod)
1085 map->vma = NULL;
1086 gntdev_put_map(priv, map);
1087 return err;
1088 }
1089
1090 static const struct file_operations gntdev_fops = {
1091 .owner = THIS_MODULE,
1092 .open = gntdev_open,
1093 .release = gntdev_release,
1094 .mmap = gntdev_mmap,
1095 .unlocked_ioctl = gntdev_ioctl
1096 };
1097
1098 static struct miscdevice gntdev_miscdev = {
1099 .minor = MISC_DYNAMIC_MINOR,
1100 .name = "xen/gntdev",
1101 .fops = &gntdev_fops,
1102 };
1103
1104 /* ------------------------------------------------------------------ */
1105
1106 static int __init gntdev_init(void)
1107 {
1108 int err;
1109
1110 if (!xen_domain())
1111 return -ENODEV;
1112
1113 use_ptemod = !xen_feature(XENFEAT_auto_translated_physmap);
1114
1115 err = misc_register(&gntdev_miscdev);
1116 if (err != 0) {
1117 pr_err("Could not register gntdev device\n");
1118 return err;
1119 }
1120 return 0;
1121 }
1122
1123 static void __exit gntdev_exit(void)
1124 {
1125 misc_deregister(&gntdev_miscdev);
1126 }
1127
1128 module_init(gntdev_init);
1129 module_exit(gntdev_exit);
1130
1131 /* ------------------------------------------------------------------ */
Linux with added FPC-III support