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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 * (c) 2018 Oleksandr Andrushchenko, EPAM Systems Inc.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 */
20
21#undef DEBUG
22
23#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
24
25#include <linux/dma-mapping.h>
26#include <linux/module.h>
27#include <linux/kernel.h>
28#include <linux/init.h>
29#include <linux/miscdevice.h>
30#include <linux/fs.h>
31#include <linux/uaccess.h>
32#include <linux/sched.h>
33#include <linux/sched/mm.h>
34#include <linux/spinlock.h>
35#include <linux/slab.h>
36#include <linux/highmem.h>
37#include <linux/refcount.h>
38
39#include <xen/xen.h>
40#include <xen/grant_table.h>
41#include <xen/balloon.h>
42#include <xen/gntdev.h>
43#include <xen/events.h>
44#include <xen/page.h>
45#include <asm/xen/hypervisor.h>
46#include <asm/xen/hypercall.h>
47
48#include "gntdev-common.h"
49#ifdef CONFIG_XEN_GNTDEV_DMABUF
50#include "gntdev-dmabuf.h"
51#endif
52
53MODULE_LICENSE("GPL");
54MODULE_AUTHOR("Derek G. Murray <Derek.Murray@cl.cam.ac.uk>, "
55 "Gerd Hoffmann <kraxel@redhat.com>");
56MODULE_DESCRIPTION("User-space granted page access driver");
57
58static int limit = 1024*1024;
59module_param(limit, int, 0644);
60MODULE_PARM_DESC(limit, "Maximum number of grants that may be mapped by "
61 "the gntdev device");
62
63static atomic_t pages_mapped = ATOMIC_INIT(0);
64
65static int use_ptemod;
66#define populate_freeable_maps use_ptemod
67
68static int unmap_grant_pages(struct gntdev_grant_map *map,
69 int offset, int pages);
70
71static struct miscdevice gntdev_miscdev;
72
73/* ------------------------------------------------------------------ */
74
75bool gntdev_account_mapped_pages(int count)
76{
77 return atomic_add_return(count, &pages_mapped) > limit;
78}
79
80static void gntdev_print_maps(struct gntdev_priv *priv,
81 char *text, int text_index)
82{
83#ifdef DEBUG
84 struct gntdev_grant_map *map;
85
86 pr_debug("%s: maps list (priv %p)\n", __func__, priv);
87 list_for_each_entry(map, &priv->maps, next)
88 pr_debug(" index %2d, count %2d %s\n",
89 map->index, map->count,
90 map->index == text_index && text ? text : "");
91#endif
92}
93
94static void gntdev_free_map(struct gntdev_grant_map *map)
95{
96 if (map == NULL)
97 return;
98
99#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
100 if (map->dma_vaddr) {
101 struct gnttab_dma_alloc_args args;
102
103 args.dev = map->dma_dev;
104 args.coherent = !!(map->dma_flags & GNTDEV_DMA_FLAG_COHERENT);
105 args.nr_pages = map->count;
106 args.pages = map->pages;
107 args.frames = map->frames;
108 args.vaddr = map->dma_vaddr;
109 args.dev_bus_addr = map->dma_bus_addr;
110
111 gnttab_dma_free_pages(&args);
112 } else
113#endif
114 if (map->pages)
115 gnttab_free_pages(map->count, map->pages);
116
117#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
118 kfree(map->frames);
119#endif
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->kunmap_ops);
126 kfree(map);
127}
128
129struct gntdev_grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count,
130 int dma_flags)
131{
132 struct gntdev_grant_map *add;
133 int i;
134
135 add = kzalloc(sizeof(*add), GFP_KERNEL);
136 if (NULL == add)
137 return NULL;
138
139 add->grants = kcalloc(count, sizeof(add->grants[0]), GFP_KERNEL);
140 add->map_ops = kcalloc(count, sizeof(add->map_ops[0]), GFP_KERNEL);
141 add->unmap_ops = kcalloc(count, sizeof(add->unmap_ops[0]), GFP_KERNEL);
142 add->kmap_ops = kcalloc(count, sizeof(add->kmap_ops[0]), GFP_KERNEL);
143 add->kunmap_ops = kcalloc(count, sizeof(add->kunmap_ops[0]), GFP_KERNEL);
144 add->pages = kcalloc(count, sizeof(add->pages[0]), GFP_KERNEL);
145 if (NULL == add->grants ||
146 NULL == add->map_ops ||
147 NULL == add->unmap_ops ||
148 NULL == add->kmap_ops ||
149 NULL == add->kunmap_ops ||
150 NULL == add->pages)
151 goto err;
152
153#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
154 add->dma_flags = dma_flags;
155
156 /*
157 * Check if this mapping is requested to be backed
158 * by a DMA buffer.
159 */
160 if (dma_flags & (GNTDEV_DMA_FLAG_WC | GNTDEV_DMA_FLAG_COHERENT)) {
161 struct gnttab_dma_alloc_args args;
162
163 add->frames = kcalloc(count, sizeof(add->frames[0]),
164 GFP_KERNEL);
165 if (!add->frames)
166 goto err;
167
168 /* Remember the device, so we can free DMA memory. */
169 add->dma_dev = priv->dma_dev;
170
171 args.dev = priv->dma_dev;
172 args.coherent = !!(dma_flags & GNTDEV_DMA_FLAG_COHERENT);
173 args.nr_pages = count;
174 args.pages = add->pages;
175 args.frames = add->frames;
176
177 if (gnttab_dma_alloc_pages(&args))
178 goto err;
179
180 add->dma_vaddr = args.vaddr;
181 add->dma_bus_addr = args.dev_bus_addr;
182 } else
183#endif
184 if (gnttab_alloc_pages(count, add->pages))
185 goto err;
186
187 for (i = 0; i < count; i++) {
188 add->map_ops[i].handle = -1;
189 add->unmap_ops[i].handle = -1;
190 add->kmap_ops[i].handle = -1;
191 add->kunmap_ops[i].handle = -1;
192 }
193
194 add->index = 0;
195 add->count = count;
196 refcount_set(&add->users, 1);
197
198 return add;
199
200err:
201 gntdev_free_map(add);
202 return NULL;
203}
204
205void gntdev_add_map(struct gntdev_priv *priv, struct gntdev_grant_map *add)
206{
207 struct gntdev_grant_map *map;
208
209 list_for_each_entry(map, &priv->maps, next) {
210 if (add->index + add->count < map->index) {
211 list_add_tail(&add->next, &map->next);
212 goto done;
213 }
214 add->index = map->index + map->count;
215 }
216 list_add_tail(&add->next, &priv->maps);
217
218done:
219 gntdev_print_maps(priv, "[new]", add->index);
220}
221
222static struct gntdev_grant_map *gntdev_find_map_index(struct gntdev_priv *priv,
223 int index, int count)
224{
225 struct gntdev_grant_map *map;
226
227 list_for_each_entry(map, &priv->maps, next) {
228 if (map->index != index)
229 continue;
230 if (count && map->count != count)
231 continue;
232 return map;
233 }
234 return NULL;
235}
236
237void gntdev_put_map(struct gntdev_priv *priv, struct gntdev_grant_map *map)
238{
239 if (!map)
240 return;
241
242 if (!refcount_dec_and_test(&map->users))
243 return;
244
245 atomic_sub(map->count, &pages_mapped);
246
247 if (map->notify.flags & UNMAP_NOTIFY_SEND_EVENT) {
248 notify_remote_via_evtchn(map->notify.event);
249 evtchn_put(map->notify.event);
250 }
251
252 if (populate_freeable_maps && priv) {
253 mutex_lock(&priv->lock);
254 list_del(&map->next);
255 mutex_unlock(&priv->lock);
256 }
257
258 if (map->pages && !use_ptemod)
259 unmap_grant_pages(map, 0, map->count);
260 gntdev_free_map(map);
261}
262
263/* ------------------------------------------------------------------ */
264
265static int find_grant_ptes(pte_t *pte, unsigned long addr, void *data)
266{
267 struct gntdev_grant_map *map = data;
268 unsigned int pgnr = (addr - map->vma->vm_start) >> PAGE_SHIFT;
269 int flags = map->flags | GNTMAP_application_map | GNTMAP_contains_pte;
270 u64 pte_maddr;
271
272 BUG_ON(pgnr >= map->count);
273 pte_maddr = arbitrary_virt_to_machine(pte).maddr;
274
275 /*
276 * Set the PTE as special to force get_user_pages_fast() fall
277 * back to the slow path. If this is not supported as part of
278 * the grant map, it will be done afterwards.
279 */
280 if (xen_feature(XENFEAT_gnttab_map_avail_bits))
281 flags |= (1 << _GNTMAP_guest_avail0);
282
283 gnttab_set_map_op(&map->map_ops[pgnr], pte_maddr, flags,
284 map->grants[pgnr].ref,
285 map->grants[pgnr].domid);
286 gnttab_set_unmap_op(&map->unmap_ops[pgnr], pte_maddr, flags,
287 -1 /* handle */);
288 return 0;
289}
290
291#ifdef CONFIG_X86
292static int set_grant_ptes_as_special(pte_t *pte, unsigned long addr, void *data)
293{
294 set_pte_at(current->mm, addr, pte, pte_mkspecial(*pte));
295 return 0;
296}
297#endif
298
299int gntdev_map_grant_pages(struct gntdev_grant_map *map)
300{
301 int i, err = 0;
302
303 if (!use_ptemod) {
304 /* Note: it could already be mapped */
305 if (map->map_ops[0].handle != -1)
306 return 0;
307 for (i = 0; i < map->count; i++) {
308 unsigned long addr = (unsigned long)
309 pfn_to_kaddr(page_to_pfn(map->pages[i]));
310 gnttab_set_map_op(&map->map_ops[i], addr, map->flags,
311 map->grants[i].ref,
312 map->grants[i].domid);
313 gnttab_set_unmap_op(&map->unmap_ops[i], addr,
314 map->flags, -1 /* handle */);
315 }
316 } else {
317 /*
318 * Setup the map_ops corresponding to the pte entries pointing
319 * to the kernel linear addresses of the struct pages.
320 * These ptes are completely different from the user ptes dealt
321 * with find_grant_ptes.
322 */
323 for (i = 0; i < map->count; i++) {
324 unsigned long address = (unsigned long)
325 pfn_to_kaddr(page_to_pfn(map->pages[i]));
326 BUG_ON(PageHighMem(map->pages[i]));
327
328 gnttab_set_map_op(&map->kmap_ops[i], address,
329 map->flags | GNTMAP_host_map,
330 map->grants[i].ref,
331 map->grants[i].domid);
332 gnttab_set_unmap_op(&map->kunmap_ops[i], address,
333 map->flags | GNTMAP_host_map, -1);
334 }
335 }
336
337 pr_debug("map %d+%d\n", map->index, map->count);
338 err = gnttab_map_refs(map->map_ops, use_ptemod ? map->kmap_ops : NULL,
339 map->pages, map->count);
340 if (err)
341 return err;
342
343 for (i = 0; i < map->count; i++) {
344 if (map->map_ops[i].status) {
345 err = -EINVAL;
346 continue;
347 }
348
349 map->unmap_ops[i].handle = map->map_ops[i].handle;
350 if (use_ptemod)
351 map->kunmap_ops[i].handle = map->kmap_ops[i].handle;
352#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
353 else if (map->dma_vaddr) {
354 unsigned long bfn;
355
356 bfn = pfn_to_bfn(page_to_pfn(map->pages[i]));
357 map->unmap_ops[i].dev_bus_addr = __pfn_to_phys(bfn);
358 }
359#endif
360 }
361 return err;
362}
363
364static int __unmap_grant_pages(struct gntdev_grant_map *map, int offset,
365 int pages)
366{
367 int i, err = 0;
368 struct gntab_unmap_queue_data unmap_data;
369
370 if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) {
371 int pgno = (map->notify.addr >> PAGE_SHIFT);
372 if (pgno >= offset && pgno < offset + pages) {
373 /* No need for kmap, pages are in lowmem */
374 uint8_t *tmp = pfn_to_kaddr(page_to_pfn(map->pages[pgno]));
375 tmp[map->notify.addr & (PAGE_SIZE-1)] = 0;
376 map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE;
377 }
378 }
379
380 unmap_data.unmap_ops = map->unmap_ops + offset;
381 unmap_data.kunmap_ops = use_ptemod ? map->kunmap_ops + offset : NULL;
382 unmap_data.pages = map->pages + offset;
383 unmap_data.count = pages;
384
385 err = gnttab_unmap_refs_sync(&unmap_data);
386 if (err)
387 return err;
388
389 for (i = 0; i < pages; i++) {
390 if (map->unmap_ops[offset+i].status)
391 err = -EINVAL;
392 pr_debug("unmap handle=%d st=%d\n",
393 map->unmap_ops[offset+i].handle,
394 map->unmap_ops[offset+i].status);
395 map->unmap_ops[offset+i].handle = -1;
396 }
397 return err;
398}
399
400static int unmap_grant_pages(struct gntdev_grant_map *map, int offset,
401 int pages)
402{
403 int range, err = 0;
404
405 pr_debug("unmap %d+%d [%d+%d]\n", map->index, map->count, offset, pages);
406
407 /* It is possible the requested range will have a "hole" where we
408 * already unmapped some of the grants. Only unmap valid ranges.
409 */
410 while (pages && !err) {
411 while (pages && map->unmap_ops[offset].handle == -1) {
412 offset++;
413 pages--;
414 }
415 range = 0;
416 while (range < pages) {
417 if (map->unmap_ops[offset+range].handle == -1)
418 break;
419 range++;
420 }
421 err = __unmap_grant_pages(map, offset, range);
422 offset += range;
423 pages -= range;
424 }
425
426 return err;
427}
428
429/* ------------------------------------------------------------------ */
430
431static void gntdev_vma_open(struct vm_area_struct *vma)
432{
433 struct gntdev_grant_map *map = vma->vm_private_data;
434
435 pr_debug("gntdev_vma_open %p\n", vma);
436 refcount_inc(&map->users);
437}
438
439static void gntdev_vma_close(struct vm_area_struct *vma)
440{
441 struct gntdev_grant_map *map = vma->vm_private_data;
442 struct file *file = vma->vm_file;
443 struct gntdev_priv *priv = file->private_data;
444
445 pr_debug("gntdev_vma_close %p\n", vma);
446 if (use_ptemod) {
447 /* It is possible that an mmu notifier could be running
448 * concurrently, so take priv->lock to ensure that the vma won't
449 * vanishing during the unmap_grant_pages call, since we will
450 * spin here until that completes. Such a concurrent call will
451 * not do any unmapping, since that has been done prior to
452 * closing the vma, but it may still iterate the unmap_ops list.
453 */
454 mutex_lock(&priv->lock);
455 map->vma = NULL;
456 mutex_unlock(&priv->lock);
457 }
458 vma->vm_private_data = NULL;
459 gntdev_put_map(priv, map);
460}
461
462static struct page *gntdev_vma_find_special_page(struct vm_area_struct *vma,
463 unsigned long addr)
464{
465 struct gntdev_grant_map *map = vma->vm_private_data;
466
467 return map->pages[(addr - map->pages_vm_start) >> PAGE_SHIFT];
468}
469
470static const struct vm_operations_struct gntdev_vmops = {
471 .open = gntdev_vma_open,
472 .close = gntdev_vma_close,
473 .find_special_page = gntdev_vma_find_special_page,
474};
475
476/* ------------------------------------------------------------------ */
477
478static bool in_range(struct gntdev_grant_map *map,
479 unsigned long start, unsigned long end)
480{
481 if (!map->vma)
482 return false;
483 if (map->vma->vm_start >= end)
484 return false;
485 if (map->vma->vm_end <= start)
486 return false;
487
488 return true;
489}
490
491static int unmap_if_in_range(struct gntdev_grant_map *map,
492 unsigned long start, unsigned long end,
493 bool blockable)
494{
495 unsigned long mstart, mend;
496 int err;
497
498 if (!in_range(map, start, end))
499 return 0;
500
501 if (!blockable)
502 return -EAGAIN;
503
504 mstart = max(start, map->vma->vm_start);
505 mend = min(end, map->vma->vm_end);
506 pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n",
507 map->index, map->count,
508 map->vma->vm_start, map->vma->vm_end,
509 start, end, mstart, mend);
510 err = unmap_grant_pages(map,
511 (mstart - map->vma->vm_start) >> PAGE_SHIFT,
512 (mend - mstart) >> PAGE_SHIFT);
513 WARN_ON(err);
514
515 return 0;
516}
517
518static int mn_invl_range_start(struct mmu_notifier *mn,
519 const struct mmu_notifier_range *range)
520{
521 struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn);
522 struct gntdev_grant_map *map;
523 int ret = 0;
524
525 if (mmu_notifier_range_blockable(range))
526 mutex_lock(&priv->lock);
527 else if (!mutex_trylock(&priv->lock))
528 return -EAGAIN;
529
530 list_for_each_entry(map, &priv->maps, next) {
531 ret = unmap_if_in_range(map, range->start, range->end,
532 mmu_notifier_range_blockable(range));
533 if (ret)
534 goto out_unlock;
535 }
536 list_for_each_entry(map, &priv->freeable_maps, next) {
537 ret = unmap_if_in_range(map, range->start, range->end,
538 mmu_notifier_range_blockable(range));
539 if (ret)
540 goto out_unlock;
541 }
542
543out_unlock:
544 mutex_unlock(&priv->lock);
545
546 return ret;
547}
548
549static void mn_release(struct mmu_notifier *mn,
550 struct mm_struct *mm)
551{
552 struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn);
553 struct gntdev_grant_map *map;
554 int err;
555
556 mutex_lock(&priv->lock);
557 list_for_each_entry(map, &priv->maps, next) {
558 if (!map->vma)
559 continue;
560 pr_debug("map %d+%d (%lx %lx)\n",
561 map->index, map->count,
562 map->vma->vm_start, map->vma->vm_end);
563 err = unmap_grant_pages(map, /* offset */ 0, map->count);
564 WARN_ON(err);
565 }
566 list_for_each_entry(map, &priv->freeable_maps, next) {
567 if (!map->vma)
568 continue;
569 pr_debug("map %d+%d (%lx %lx)\n",
570 map->index, map->count,
571 map->vma->vm_start, map->vma->vm_end);
572 err = unmap_grant_pages(map, /* offset */ 0, map->count);
573 WARN_ON(err);
574 }
575 mutex_unlock(&priv->lock);
576}
577
578static const struct mmu_notifier_ops gntdev_mmu_ops = {
579 .release = mn_release,
580 .invalidate_range_start = mn_invl_range_start,
581};
582
583/* ------------------------------------------------------------------ */
584
585static int gntdev_open(struct inode *inode, struct file *flip)
586{
587 struct gntdev_priv *priv;
588 int ret = 0;
589
590 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
591 if (!priv)
592 return -ENOMEM;
593
594 INIT_LIST_HEAD(&priv->maps);
595 INIT_LIST_HEAD(&priv->freeable_maps);
596 mutex_init(&priv->lock);
597
598#ifdef CONFIG_XEN_GNTDEV_DMABUF
599 priv->dmabuf_priv = gntdev_dmabuf_init(flip);
600 if (IS_ERR(priv->dmabuf_priv)) {
601 ret = PTR_ERR(priv->dmabuf_priv);
602 kfree(priv);
603 return ret;
604 }
605#endif
606
607 if (use_ptemod) {
608 priv->mm = get_task_mm(current);
609 if (!priv->mm) {
610 kfree(priv);
611 return -ENOMEM;
612 }
613 priv->mn.ops = &gntdev_mmu_ops;
614 ret = mmu_notifier_register(&priv->mn, priv->mm);
615 mmput(priv->mm);
616 }
617
618 if (ret) {
619 kfree(priv);
620 return ret;
621 }
622
623 flip->private_data = priv;
624#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
625 priv->dma_dev = gntdev_miscdev.this_device;
626 dma_coerce_mask_and_coherent(priv->dma_dev, DMA_BIT_MASK(64));
627#endif
628 pr_debug("priv %p\n", priv);
629
630 return 0;
631}
632
633static int gntdev_release(struct inode *inode, struct file *flip)
634{
635 struct gntdev_priv *priv = flip->private_data;
636 struct gntdev_grant_map *map;
637
638 pr_debug("priv %p\n", priv);
639
640 mutex_lock(&priv->lock);
641 while (!list_empty(&priv->maps)) {
642 map = list_entry(priv->maps.next,
643 struct gntdev_grant_map, next);
644 list_del(&map->next);
645 gntdev_put_map(NULL /* already removed */, map);
646 }
647 WARN_ON(!list_empty(&priv->freeable_maps));
648 mutex_unlock(&priv->lock);
649
650#ifdef CONFIG_XEN_GNTDEV_DMABUF
651 gntdev_dmabuf_fini(priv->dmabuf_priv);
652#endif
653
654 if (use_ptemod)
655 mmu_notifier_unregister(&priv->mn, priv->mm);
656
657 kfree(priv);
658 return 0;
659}
660
661static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv,
662 struct ioctl_gntdev_map_grant_ref __user *u)
663{
664 struct ioctl_gntdev_map_grant_ref op;
665 struct gntdev_grant_map *map;
666 int err;
667
668 if (copy_from_user(&op, u, sizeof(op)) != 0)
669 return -EFAULT;
670 pr_debug("priv %p, add %d\n", priv, op.count);
671 if (unlikely(op.count <= 0))
672 return -EINVAL;
673
674 err = -ENOMEM;
675 map = gntdev_alloc_map(priv, op.count, 0 /* This is not a dma-buf. */);
676 if (!map)
677 return err;
678
679 if (unlikely(gntdev_account_mapped_pages(op.count))) {
680 pr_debug("can't map: over limit\n");
681 gntdev_put_map(NULL, map);
682 return err;
683 }
684
685 if (copy_from_user(map->grants, &u->refs,
686 sizeof(map->grants[0]) * op.count) != 0) {
687 gntdev_put_map(NULL, map);
688 return -EFAULT;
689 }
690
691 mutex_lock(&priv->lock);
692 gntdev_add_map(priv, map);
693 op.index = map->index << PAGE_SHIFT;
694 mutex_unlock(&priv->lock);
695
696 if (copy_to_user(u, &op, sizeof(op)) != 0)
697 return -EFAULT;
698
699 return 0;
700}
701
702static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv *priv,
703 struct ioctl_gntdev_unmap_grant_ref __user *u)
704{
705 struct ioctl_gntdev_unmap_grant_ref op;
706 struct gntdev_grant_map *map;
707 int err = -ENOENT;
708
709 if (copy_from_user(&op, u, sizeof(op)) != 0)
710 return -EFAULT;
711 pr_debug("priv %p, del %d+%d\n", priv, (int)op.index, (int)op.count);
712
713 mutex_lock(&priv->lock);
714 map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count);
715 if (map) {
716 list_del(&map->next);
717 if (populate_freeable_maps)
718 list_add_tail(&map->next, &priv->freeable_maps);
719 err = 0;
720 }
721 mutex_unlock(&priv->lock);
722 if (map)
723 gntdev_put_map(priv, map);
724 return err;
725}
726
727static long gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv *priv,
728 struct ioctl_gntdev_get_offset_for_vaddr __user *u)
729{
730 struct ioctl_gntdev_get_offset_for_vaddr op;
731 struct vm_area_struct *vma;
732 struct gntdev_grant_map *map;
733 int rv = -EINVAL;
734
735 if (copy_from_user(&op, u, sizeof(op)) != 0)
736 return -EFAULT;
737 pr_debug("priv %p, offset for vaddr %lx\n", priv, (unsigned long)op.vaddr);
738
739 down_read(¤t->mm->mmap_sem);
740 vma = find_vma(current->mm, op.vaddr);
741 if (!vma || vma->vm_ops != &gntdev_vmops)
742 goto out_unlock;
743
744 map = vma->vm_private_data;
745 if (!map)
746 goto out_unlock;
747
748 op.offset = map->index << PAGE_SHIFT;
749 op.count = map->count;
750 rv = 0;
751
752 out_unlock:
753 up_read(¤t->mm->mmap_sem);
754
755 if (rv == 0 && copy_to_user(u, &op, sizeof(op)) != 0)
756 return -EFAULT;
757 return rv;
758}
759
760static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u)
761{
762 struct ioctl_gntdev_unmap_notify op;
763 struct gntdev_grant_map *map;
764 int rc;
765 int out_flags;
766 unsigned int out_event;
767
768 if (copy_from_user(&op, u, sizeof(op)))
769 return -EFAULT;
770
771 if (op.action & ~(UNMAP_NOTIFY_CLEAR_BYTE|UNMAP_NOTIFY_SEND_EVENT))
772 return -EINVAL;
773
774 /* We need to grab a reference to the event channel we are going to use
775 * to send the notify before releasing the reference we may already have
776 * (if someone has called this ioctl twice). This is required so that
777 * it is possible to change the clear_byte part of the notification
778 * without disturbing the event channel part, which may now be the last
779 * reference to that event channel.
780 */
781 if (op.action & UNMAP_NOTIFY_SEND_EVENT) {
782 if (evtchn_get(op.event_channel_port))
783 return -EINVAL;
784 }
785
786 out_flags = op.action;
787 out_event = op.event_channel_port;
788
789 mutex_lock(&priv->lock);
790
791 list_for_each_entry(map, &priv->maps, next) {
792 uint64_t begin = map->index << PAGE_SHIFT;
793 uint64_t end = (map->index + map->count) << PAGE_SHIFT;
794 if (op.index >= begin && op.index < end)
795 goto found;
796 }
797 rc = -ENOENT;
798 goto unlock_out;
799
800 found:
801 if ((op.action & UNMAP_NOTIFY_CLEAR_BYTE) &&
802 (map->flags & GNTMAP_readonly)) {
803 rc = -EINVAL;
804 goto unlock_out;
805 }
806
807 out_flags = map->notify.flags;
808 out_event = map->notify.event;
809
810 map->notify.flags = op.action;
811 map->notify.addr = op.index - (map->index << PAGE_SHIFT);
812 map->notify.event = op.event_channel_port;
813
814 rc = 0;
815
816 unlock_out:
817 mutex_unlock(&priv->lock);
818
819 /* Drop the reference to the event channel we did not save in the map */
820 if (out_flags & UNMAP_NOTIFY_SEND_EVENT)
821 evtchn_put(out_event);
822
823 return rc;
824}
825
826#define GNTDEV_COPY_BATCH 16
827
828struct gntdev_copy_batch {
829 struct gnttab_copy ops[GNTDEV_COPY_BATCH];
830 struct page *pages[GNTDEV_COPY_BATCH];
831 s16 __user *status[GNTDEV_COPY_BATCH];
832 unsigned int nr_ops;
833 unsigned int nr_pages;
834};
835
836static int gntdev_get_page(struct gntdev_copy_batch *batch, void __user *virt,
837 bool writeable, unsigned long *gfn)
838{
839 unsigned long addr = (unsigned long)virt;
840 struct page *page;
841 unsigned long xen_pfn;
842 int ret;
843
844 ret = get_user_pages_fast(addr, 1, writeable ? FOLL_WRITE : 0, &page);
845 if (ret < 0)
846 return ret;
847
848 batch->pages[batch->nr_pages++] = page;
849
850 xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(addr & ~PAGE_MASK);
851 *gfn = pfn_to_gfn(xen_pfn);
852
853 return 0;
854}
855
856static void gntdev_put_pages(struct gntdev_copy_batch *batch)
857{
858 unsigned int i;
859
860 for (i = 0; i < batch->nr_pages; i++)
861 put_page(batch->pages[i]);
862 batch->nr_pages = 0;
863}
864
865static int gntdev_copy(struct gntdev_copy_batch *batch)
866{
867 unsigned int i;
868
869 gnttab_batch_copy(batch->ops, batch->nr_ops);
870 gntdev_put_pages(batch);
871
872 /*
873 * For each completed op, update the status if the op failed
874 * and all previous ops for the segment were successful.
875 */
876 for (i = 0; i < batch->nr_ops; i++) {
877 s16 status = batch->ops[i].status;
878 s16 old_status;
879
880 if (status == GNTST_okay)
881 continue;
882
883 if (__get_user(old_status, batch->status[i]))
884 return -EFAULT;
885
886 if (old_status != GNTST_okay)
887 continue;
888
889 if (__put_user(status, batch->status[i]))
890 return -EFAULT;
891 }
892
893 batch->nr_ops = 0;
894 return 0;
895}
896
897static int gntdev_grant_copy_seg(struct gntdev_copy_batch *batch,
898 struct gntdev_grant_copy_segment *seg,
899 s16 __user *status)
900{
901 uint16_t copied = 0;
902
903 /*
904 * Disallow local -> local copies since there is only space in
905 * batch->pages for one page per-op and this would be a very
906 * expensive memcpy().
907 */
908 if (!(seg->flags & (GNTCOPY_source_gref | GNTCOPY_dest_gref)))
909 return -EINVAL;
910
911 /* Can't cross page if source/dest is a grant ref. */
912 if (seg->flags & GNTCOPY_source_gref) {
913 if (seg->source.foreign.offset + seg->len > XEN_PAGE_SIZE)
914 return -EINVAL;
915 }
916 if (seg->flags & GNTCOPY_dest_gref) {
917 if (seg->dest.foreign.offset + seg->len > XEN_PAGE_SIZE)
918 return -EINVAL;
919 }
920
921 if (put_user(GNTST_okay, status))
922 return -EFAULT;
923
924 while (copied < seg->len) {
925 struct gnttab_copy *op;
926 void __user *virt;
927 size_t len, off;
928 unsigned long gfn;
929 int ret;
930
931 if (batch->nr_ops >= GNTDEV_COPY_BATCH) {
932 ret = gntdev_copy(batch);
933 if (ret < 0)
934 return ret;
935 }
936
937 len = seg->len - copied;
938
939 op = &batch->ops[batch->nr_ops];
940 op->flags = 0;
941
942 if (seg->flags & GNTCOPY_source_gref) {
943 op->source.u.ref = seg->source.foreign.ref;
944 op->source.domid = seg->source.foreign.domid;
945 op->source.offset = seg->source.foreign.offset + copied;
946 op->flags |= GNTCOPY_source_gref;
947 } else {
948 virt = seg->source.virt + copied;
949 off = (unsigned long)virt & ~XEN_PAGE_MASK;
950 len = min(len, (size_t)XEN_PAGE_SIZE - off);
951
952 ret = gntdev_get_page(batch, virt, false, &gfn);
953 if (ret < 0)
954 return ret;
955
956 op->source.u.gmfn = gfn;
957 op->source.domid = DOMID_SELF;
958 op->source.offset = off;
959 }
960
961 if (seg->flags & GNTCOPY_dest_gref) {
962 op->dest.u.ref = seg->dest.foreign.ref;
963 op->dest.domid = seg->dest.foreign.domid;
964 op->dest.offset = seg->dest.foreign.offset + copied;
965 op->flags |= GNTCOPY_dest_gref;
966 } else {
967 virt = seg->dest.virt + copied;
968 off = (unsigned long)virt & ~XEN_PAGE_MASK;
969 len = min(len, (size_t)XEN_PAGE_SIZE - off);
970
971 ret = gntdev_get_page(batch, virt, true, &gfn);
972 if (ret < 0)
973 return ret;
974
975 op->dest.u.gmfn = gfn;
976 op->dest.domid = DOMID_SELF;
977 op->dest.offset = off;
978 }
979
980 op->len = len;
981 copied += len;
982
983 batch->status[batch->nr_ops] = status;
984 batch->nr_ops++;
985 }
986
987 return 0;
988}
989
990static long gntdev_ioctl_grant_copy(struct gntdev_priv *priv, void __user *u)
991{
992 struct ioctl_gntdev_grant_copy copy;
993 struct gntdev_copy_batch batch;
994 unsigned int i;
995 int ret = 0;
996
997 if (copy_from_user(©, u, sizeof(copy)))
998 return -EFAULT;
999
1000 batch.nr_ops = 0;
1001 batch.nr_pages = 0;
1002
1003 for (i = 0; i < copy.count; i++) {
1004 struct gntdev_grant_copy_segment seg;
1005
1006 if (copy_from_user(&seg, ©.segments[i], sizeof(seg))) {
1007 ret = -EFAULT;
1008 goto out;
1009 }
1010
1011 ret = gntdev_grant_copy_seg(&batch, &seg, ©.segments[i].status);
1012 if (ret < 0)
1013 goto out;
1014
1015 cond_resched();
1016 }
1017 if (batch.nr_ops)
1018 ret = gntdev_copy(&batch);
1019 return ret;
1020
1021 out:
1022 gntdev_put_pages(&batch);
1023 return ret;
1024}
1025
1026static long gntdev_ioctl(struct file *flip,
1027 unsigned int cmd, unsigned long arg)
1028{
1029 struct gntdev_priv *priv = flip->private_data;
1030 void __user *ptr = (void __user *)arg;
1031
1032 switch (cmd) {
1033 case IOCTL_GNTDEV_MAP_GRANT_REF:
1034 return gntdev_ioctl_map_grant_ref(priv, ptr);
1035
1036 case IOCTL_GNTDEV_UNMAP_GRANT_REF:
1037 return gntdev_ioctl_unmap_grant_ref(priv, ptr);
1038
1039 case IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR:
1040 return gntdev_ioctl_get_offset_for_vaddr(priv, ptr);
1041
1042 case IOCTL_GNTDEV_SET_UNMAP_NOTIFY:
1043 return gntdev_ioctl_notify(priv, ptr);
1044
1045 case IOCTL_GNTDEV_GRANT_COPY:
1046 return gntdev_ioctl_grant_copy(priv, ptr);
1047
1048#ifdef CONFIG_XEN_GNTDEV_DMABUF
1049 case IOCTL_GNTDEV_DMABUF_EXP_FROM_REFS:
1050 return gntdev_ioctl_dmabuf_exp_from_refs(priv, use_ptemod, ptr);
1051
1052 case IOCTL_GNTDEV_DMABUF_EXP_WAIT_RELEASED:
1053 return gntdev_ioctl_dmabuf_exp_wait_released(priv, ptr);
1054
1055 case IOCTL_GNTDEV_DMABUF_IMP_TO_REFS:
1056 return gntdev_ioctl_dmabuf_imp_to_refs(priv, ptr);
1057
1058 case IOCTL_GNTDEV_DMABUF_IMP_RELEASE:
1059 return gntdev_ioctl_dmabuf_imp_release(priv, ptr);
1060#endif
1061
1062 default:
1063 pr_debug("priv %p, unknown cmd %x\n", priv, cmd);
1064 return -ENOIOCTLCMD;
1065 }
1066
1067 return 0;
1068}
1069
1070static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
1071{
1072 struct gntdev_priv *priv = flip->private_data;
1073 int index = vma->vm_pgoff;
1074 int count = vma_pages(vma);
1075 struct gntdev_grant_map *map;
1076 int err = -EINVAL;
1077
1078 if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED))
1079 return -EINVAL;
1080
1081 pr_debug("map %d+%d at %lx (pgoff %lx)\n",
1082 index, count, vma->vm_start, vma->vm_pgoff);
1083
1084 mutex_lock(&priv->lock);
1085 map = gntdev_find_map_index(priv, index, count);
1086 if (!map)
1087 goto unlock_out;
1088 if (use_ptemod && map->vma)
1089 goto unlock_out;
1090 if (use_ptemod && priv->mm != vma->vm_mm) {
1091 pr_warn("Huh? Other mm?\n");
1092 goto unlock_out;
1093 }
1094
1095 refcount_inc(&map->users);
1096
1097 vma->vm_ops = &gntdev_vmops;
1098
1099 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP | VM_MIXEDMAP;
1100
1101 if (use_ptemod)
1102 vma->vm_flags |= VM_DONTCOPY;
1103
1104 vma->vm_private_data = map;
1105
1106 if (use_ptemod)
1107 map->vma = vma;
1108
1109 if (map->flags) {
1110 if ((vma->vm_flags & VM_WRITE) &&
1111 (map->flags & GNTMAP_readonly))
1112 goto out_unlock_put;
1113 } else {
1114 map->flags = GNTMAP_host_map;
1115 if (!(vma->vm_flags & VM_WRITE))
1116 map->flags |= GNTMAP_readonly;
1117 }
1118
1119 mutex_unlock(&priv->lock);
1120
1121 if (use_ptemod) {
1122 map->pages_vm_start = vma->vm_start;
1123 err = apply_to_page_range(vma->vm_mm, vma->vm_start,
1124 vma->vm_end - vma->vm_start,
1125 find_grant_ptes, map);
1126 if (err) {
1127 pr_warn("find_grant_ptes() failure.\n");
1128 goto out_put_map;
1129 }
1130 }
1131
1132 err = gntdev_map_grant_pages(map);
1133 if (err)
1134 goto out_put_map;
1135
1136 if (!use_ptemod) {
1137 err = vm_map_pages_zero(vma, map->pages, map->count);
1138 if (err)
1139 goto out_put_map;
1140 } else {
1141#ifdef CONFIG_X86
1142 /*
1143 * If the PTEs were not made special by the grant map
1144 * hypercall, do so here.
1145 *
1146 * This is racy since the mapping is already visible
1147 * to userspace but userspace should be well-behaved
1148 * enough to not touch it until the mmap() call
1149 * returns.
1150 */
1151 if (!xen_feature(XENFEAT_gnttab_map_avail_bits)) {
1152 apply_to_page_range(vma->vm_mm, vma->vm_start,
1153 vma->vm_end - vma->vm_start,
1154 set_grant_ptes_as_special, NULL);
1155 }
1156#endif
1157 }
1158
1159 return 0;
1160
1161unlock_out:
1162 mutex_unlock(&priv->lock);
1163 return err;
1164
1165out_unlock_put:
1166 mutex_unlock(&priv->lock);
1167out_put_map:
1168 if (use_ptemod) {
1169 map->vma = NULL;
1170 unmap_grant_pages(map, 0, map->count);
1171 }
1172 gntdev_put_map(priv, map);
1173 return err;
1174}
1175
1176static const struct file_operations gntdev_fops = {
1177 .owner = THIS_MODULE,
1178 .open = gntdev_open,
1179 .release = gntdev_release,
1180 .mmap = gntdev_mmap,
1181 .unlocked_ioctl = gntdev_ioctl
1182};
1183
1184static struct miscdevice gntdev_miscdev = {
1185 .minor = MISC_DYNAMIC_MINOR,
1186 .name = "xen/gntdev",
1187 .fops = &gntdev_fops,
1188};
1189
1190/* ------------------------------------------------------------------ */
1191
1192static int __init gntdev_init(void)
1193{
1194 int err;
1195
1196 if (!xen_domain())
1197 return -ENODEV;
1198
1199 use_ptemod = !xen_feature(XENFEAT_auto_translated_physmap);
1200
1201 err = misc_register(&gntdev_miscdev);
1202 if (err != 0) {
1203 pr_err("Could not register gntdev device\n");
1204 return err;
1205 }
1206 return 0;
1207}
1208
1209static void __exit gntdev_exit(void)
1210{
1211 misc_deregister(&gntdev_miscdev);
1212}
1213
1214module_init(gntdev_init);
1215module_exit(gntdev_exit);
1216
1217/* ------------------------------------------------------------------ */
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 * (c) 2018 Oleksandr Andrushchenko, EPAM Systems Inc.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 */
20
21#undef DEBUG
22
23#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
24
25#include <linux/dma-mapping.h>
26#include <linux/module.h>
27#include <linux/kernel.h>
28#include <linux/init.h>
29#include <linux/miscdevice.h>
30#include <linux/fs.h>
31#include <linux/uaccess.h>
32#include <linux/sched.h>
33#include <linux/sched/mm.h>
34#include <linux/spinlock.h>
35#include <linux/slab.h>
36#include <linux/highmem.h>
37#include <linux/refcount.h>
38
39#include <xen/xen.h>
40#include <xen/grant_table.h>
41#include <xen/balloon.h>
42#include <xen/gntdev.h>
43#include <xen/events.h>
44#include <xen/page.h>
45#include <asm/xen/hypervisor.h>
46#include <asm/xen/hypercall.h>
47
48#include "gntdev-common.h"
49#ifdef CONFIG_XEN_GNTDEV_DMABUF
50#include "gntdev-dmabuf.h"
51#endif
52
53MODULE_LICENSE("GPL");
54MODULE_AUTHOR("Derek G. Murray <Derek.Murray@cl.cam.ac.uk>, "
55 "Gerd Hoffmann <kraxel@redhat.com>");
56MODULE_DESCRIPTION("User-space granted page access driver");
57
58static unsigned int limit = 64*1024;
59module_param(limit, uint, 0644);
60MODULE_PARM_DESC(limit,
61 "Maximum number of grants that may be mapped by one mapping request");
62
63static int use_ptemod;
64
65static int unmap_grant_pages(struct gntdev_grant_map *map,
66 int offset, int pages);
67
68static struct miscdevice gntdev_miscdev;
69
70/* ------------------------------------------------------------------ */
71
72bool gntdev_test_page_count(unsigned int count)
73{
74 return !count || count > limit;
75}
76
77static void gntdev_print_maps(struct gntdev_priv *priv,
78 char *text, int text_index)
79{
80#ifdef DEBUG
81 struct gntdev_grant_map *map;
82
83 pr_debug("%s: maps list (priv %p)\n", __func__, priv);
84 list_for_each_entry(map, &priv->maps, next)
85 pr_debug(" index %2d, count %2d %s\n",
86 map->index, map->count,
87 map->index == text_index && text ? text : "");
88#endif
89}
90
91static void gntdev_free_map(struct gntdev_grant_map *map)
92{
93 if (map == NULL)
94 return;
95
96#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
97 if (map->dma_vaddr) {
98 struct gnttab_dma_alloc_args args;
99
100 args.dev = map->dma_dev;
101 args.coherent = !!(map->dma_flags & GNTDEV_DMA_FLAG_COHERENT);
102 args.nr_pages = map->count;
103 args.pages = map->pages;
104 args.frames = map->frames;
105 args.vaddr = map->dma_vaddr;
106 args.dev_bus_addr = map->dma_bus_addr;
107
108 gnttab_dma_free_pages(&args);
109 } else
110#endif
111 if (map->pages)
112 gnttab_free_pages(map->count, map->pages);
113
114#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
115 kvfree(map->frames);
116#endif
117 kvfree(map->pages);
118 kvfree(map->grants);
119 kvfree(map->map_ops);
120 kvfree(map->unmap_ops);
121 kvfree(map->kmap_ops);
122 kvfree(map->kunmap_ops);
123 kfree(map);
124}
125
126struct gntdev_grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count,
127 int dma_flags)
128{
129 struct gntdev_grant_map *add;
130 int i;
131
132 add = kzalloc(sizeof(*add), GFP_KERNEL);
133 if (NULL == add)
134 return NULL;
135
136 add->grants = kvmalloc_array(count, sizeof(add->grants[0]),
137 GFP_KERNEL);
138 add->map_ops = kvmalloc_array(count, sizeof(add->map_ops[0]),
139 GFP_KERNEL);
140 add->unmap_ops = kvmalloc_array(count, sizeof(add->unmap_ops[0]),
141 GFP_KERNEL);
142 add->pages = kvcalloc(count, sizeof(add->pages[0]), GFP_KERNEL);
143 if (NULL == add->grants ||
144 NULL == add->map_ops ||
145 NULL == add->unmap_ops ||
146 NULL == add->pages)
147 goto err;
148 if (use_ptemod) {
149 add->kmap_ops = kvmalloc_array(count, sizeof(add->kmap_ops[0]),
150 GFP_KERNEL);
151 add->kunmap_ops = kvmalloc_array(count, sizeof(add->kunmap_ops[0]),
152 GFP_KERNEL);
153 if (NULL == add->kmap_ops || NULL == add->kunmap_ops)
154 goto err;
155 }
156
157#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
158 add->dma_flags = dma_flags;
159
160 /*
161 * Check if this mapping is requested to be backed
162 * by a DMA buffer.
163 */
164 if (dma_flags & (GNTDEV_DMA_FLAG_WC | GNTDEV_DMA_FLAG_COHERENT)) {
165 struct gnttab_dma_alloc_args args;
166
167 add->frames = kvcalloc(count, sizeof(add->frames[0]),
168 GFP_KERNEL);
169 if (!add->frames)
170 goto err;
171
172 /* Remember the device, so we can free DMA memory. */
173 add->dma_dev = priv->dma_dev;
174
175 args.dev = priv->dma_dev;
176 args.coherent = !!(dma_flags & GNTDEV_DMA_FLAG_COHERENT);
177 args.nr_pages = count;
178 args.pages = add->pages;
179 args.frames = add->frames;
180
181 if (gnttab_dma_alloc_pages(&args))
182 goto err;
183
184 add->dma_vaddr = args.vaddr;
185 add->dma_bus_addr = args.dev_bus_addr;
186 } else
187#endif
188 if (gnttab_alloc_pages(count, add->pages))
189 goto err;
190
191 for (i = 0; i < count; i++) {
192 add->grants[i].domid = DOMID_INVALID;
193 add->grants[i].ref = INVALID_GRANT_REF;
194 add->map_ops[i].handle = INVALID_GRANT_HANDLE;
195 add->unmap_ops[i].handle = INVALID_GRANT_HANDLE;
196 if (use_ptemod) {
197 add->kmap_ops[i].handle = INVALID_GRANT_HANDLE;
198 add->kunmap_ops[i].handle = INVALID_GRANT_HANDLE;
199 }
200 }
201
202 add->index = 0;
203 add->count = count;
204 refcount_set(&add->users, 1);
205
206 return add;
207
208err:
209 gntdev_free_map(add);
210 return NULL;
211}
212
213void gntdev_add_map(struct gntdev_priv *priv, struct gntdev_grant_map *add)
214{
215 struct gntdev_grant_map *map;
216
217 list_for_each_entry(map, &priv->maps, next) {
218 if (add->index + add->count < map->index) {
219 list_add_tail(&add->next, &map->next);
220 goto done;
221 }
222 add->index = map->index + map->count;
223 }
224 list_add_tail(&add->next, &priv->maps);
225
226done:
227 gntdev_print_maps(priv, "[new]", add->index);
228}
229
230static struct gntdev_grant_map *gntdev_find_map_index(struct gntdev_priv *priv,
231 int index, int count)
232{
233 struct gntdev_grant_map *map;
234
235 list_for_each_entry(map, &priv->maps, next) {
236 if (map->index != index)
237 continue;
238 if (count && map->count != count)
239 continue;
240 return map;
241 }
242 return NULL;
243}
244
245void gntdev_put_map(struct gntdev_priv *priv, struct gntdev_grant_map *map)
246{
247 if (!map)
248 return;
249
250 if (!refcount_dec_and_test(&map->users))
251 return;
252
253 if (map->notify.flags & UNMAP_NOTIFY_SEND_EVENT) {
254 notify_remote_via_evtchn(map->notify.event);
255 evtchn_put(map->notify.event);
256 }
257
258 if (map->pages && !use_ptemod)
259 unmap_grant_pages(map, 0, map->count);
260 gntdev_free_map(map);
261}
262
263/* ------------------------------------------------------------------ */
264
265static int find_grant_ptes(pte_t *pte, unsigned long addr, void *data)
266{
267 struct gntdev_grant_map *map = data;
268 unsigned int pgnr = (addr - map->vma->vm_start) >> PAGE_SHIFT;
269 int flags = map->flags | GNTMAP_application_map | GNTMAP_contains_pte;
270 u64 pte_maddr;
271
272 BUG_ON(pgnr >= map->count);
273 pte_maddr = arbitrary_virt_to_machine(pte).maddr;
274
275 /*
276 * Set the PTE as special to force get_user_pages_fast() fall
277 * back to the slow path. If this is not supported as part of
278 * the grant map, it will be done afterwards.
279 */
280 if (xen_feature(XENFEAT_gnttab_map_avail_bits))
281 flags |= (1 << _GNTMAP_guest_avail0);
282
283 gnttab_set_map_op(&map->map_ops[pgnr], pte_maddr, flags,
284 map->grants[pgnr].ref,
285 map->grants[pgnr].domid);
286 gnttab_set_unmap_op(&map->unmap_ops[pgnr], pte_maddr, flags,
287 INVALID_GRANT_HANDLE);
288 return 0;
289}
290
291#ifdef CONFIG_X86
292static int set_grant_ptes_as_special(pte_t *pte, unsigned long addr, void *data)
293{
294 set_pte_at(current->mm, addr, pte, pte_mkspecial(*pte));
295 return 0;
296}
297#endif
298
299int gntdev_map_grant_pages(struct gntdev_grant_map *map)
300{
301 int i, err = 0;
302
303 if (!use_ptemod) {
304 /* Note: it could already be mapped */
305 if (map->map_ops[0].handle != INVALID_GRANT_HANDLE)
306 return 0;
307 for (i = 0; i < map->count; i++) {
308 unsigned long addr = (unsigned long)
309 pfn_to_kaddr(page_to_pfn(map->pages[i]));
310 gnttab_set_map_op(&map->map_ops[i], addr, map->flags,
311 map->grants[i].ref,
312 map->grants[i].domid);
313 gnttab_set_unmap_op(&map->unmap_ops[i], addr,
314 map->flags, INVALID_GRANT_HANDLE);
315 }
316 } else {
317 /*
318 * Setup the map_ops corresponding to the pte entries pointing
319 * to the kernel linear addresses of the struct pages.
320 * These ptes are completely different from the user ptes dealt
321 * with find_grant_ptes.
322 * Note that GNTMAP_device_map isn't needed here: The
323 * dev_bus_addr output field gets consumed only from ->map_ops,
324 * and by not requesting it when mapping we also avoid needing
325 * to mirror dev_bus_addr into ->unmap_ops (and holding an extra
326 * reference to the page in the hypervisor).
327 */
328 unsigned int flags = (map->flags & ~GNTMAP_device_map) |
329 GNTMAP_host_map;
330
331 for (i = 0; i < map->count; i++) {
332 unsigned long address = (unsigned long)
333 pfn_to_kaddr(page_to_pfn(map->pages[i]));
334 BUG_ON(PageHighMem(map->pages[i]));
335
336 gnttab_set_map_op(&map->kmap_ops[i], address, flags,
337 map->grants[i].ref,
338 map->grants[i].domid);
339 gnttab_set_unmap_op(&map->kunmap_ops[i], address,
340 flags, INVALID_GRANT_HANDLE);
341 }
342 }
343
344 pr_debug("map %d+%d\n", map->index, map->count);
345 err = gnttab_map_refs(map->map_ops, map->kmap_ops, map->pages,
346 map->count);
347
348 for (i = 0; i < map->count; i++) {
349 if (map->map_ops[i].status == GNTST_okay)
350 map->unmap_ops[i].handle = map->map_ops[i].handle;
351 else if (!err)
352 err = -EINVAL;
353
354 if (map->flags & GNTMAP_device_map)
355 map->unmap_ops[i].dev_bus_addr = map->map_ops[i].dev_bus_addr;
356
357 if (use_ptemod) {
358 if (map->kmap_ops[i].status == GNTST_okay)
359 map->kunmap_ops[i].handle = map->kmap_ops[i].handle;
360 else if (!err)
361 err = -EINVAL;
362 }
363 }
364 return err;
365}
366
367static int __unmap_grant_pages(struct gntdev_grant_map *map, int offset,
368 int pages)
369{
370 int i, err = 0;
371 struct gntab_unmap_queue_data unmap_data;
372
373 if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) {
374 int pgno = (map->notify.addr >> PAGE_SHIFT);
375 if (pgno >= offset && pgno < offset + pages) {
376 /* No need for kmap, pages are in lowmem */
377 uint8_t *tmp = pfn_to_kaddr(page_to_pfn(map->pages[pgno]));
378 tmp[map->notify.addr & (PAGE_SIZE-1)] = 0;
379 map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE;
380 }
381 }
382
383 unmap_data.unmap_ops = map->unmap_ops + offset;
384 unmap_data.kunmap_ops = use_ptemod ? map->kunmap_ops + offset : NULL;
385 unmap_data.pages = map->pages + offset;
386 unmap_data.count = pages;
387
388 err = gnttab_unmap_refs_sync(&unmap_data);
389 if (err)
390 return err;
391
392 for (i = 0; i < pages; i++) {
393 if (map->unmap_ops[offset+i].status)
394 err = -EINVAL;
395 pr_debug("unmap handle=%d st=%d\n",
396 map->unmap_ops[offset+i].handle,
397 map->unmap_ops[offset+i].status);
398 map->unmap_ops[offset+i].handle = INVALID_GRANT_HANDLE;
399 if (use_ptemod) {
400 if (map->kunmap_ops[offset+i].status)
401 err = -EINVAL;
402 pr_debug("kunmap handle=%u st=%d\n",
403 map->kunmap_ops[offset+i].handle,
404 map->kunmap_ops[offset+i].status);
405 map->kunmap_ops[offset+i].handle = INVALID_GRANT_HANDLE;
406 }
407 }
408 return err;
409}
410
411static int unmap_grant_pages(struct gntdev_grant_map *map, int offset,
412 int pages)
413{
414 int range, err = 0;
415
416 pr_debug("unmap %d+%d [%d+%d]\n", map->index, map->count, offset, pages);
417
418 /* It is possible the requested range will have a "hole" where we
419 * already unmapped some of the grants. Only unmap valid ranges.
420 */
421 while (pages && !err) {
422 while (pages &&
423 map->unmap_ops[offset].handle == INVALID_GRANT_HANDLE) {
424 offset++;
425 pages--;
426 }
427 range = 0;
428 while (range < pages) {
429 if (map->unmap_ops[offset + range].handle ==
430 INVALID_GRANT_HANDLE)
431 break;
432 range++;
433 }
434 err = __unmap_grant_pages(map, offset, range);
435 offset += range;
436 pages -= range;
437 }
438
439 return err;
440}
441
442/* ------------------------------------------------------------------ */
443
444static void gntdev_vma_open(struct vm_area_struct *vma)
445{
446 struct gntdev_grant_map *map = vma->vm_private_data;
447
448 pr_debug("gntdev_vma_open %p\n", vma);
449 refcount_inc(&map->users);
450}
451
452static void gntdev_vma_close(struct vm_area_struct *vma)
453{
454 struct gntdev_grant_map *map = vma->vm_private_data;
455 struct file *file = vma->vm_file;
456 struct gntdev_priv *priv = file->private_data;
457
458 pr_debug("gntdev_vma_close %p\n", vma);
459 if (use_ptemod) {
460 WARN_ON(map->vma != vma);
461 mmu_interval_notifier_remove(&map->notifier);
462 map->vma = NULL;
463 }
464 vma->vm_private_data = NULL;
465 gntdev_put_map(priv, map);
466}
467
468static struct page *gntdev_vma_find_special_page(struct vm_area_struct *vma,
469 unsigned long addr)
470{
471 struct gntdev_grant_map *map = vma->vm_private_data;
472
473 return map->pages[(addr - map->pages_vm_start) >> PAGE_SHIFT];
474}
475
476static const struct vm_operations_struct gntdev_vmops = {
477 .open = gntdev_vma_open,
478 .close = gntdev_vma_close,
479 .find_special_page = gntdev_vma_find_special_page,
480};
481
482/* ------------------------------------------------------------------ */
483
484static bool gntdev_invalidate(struct mmu_interval_notifier *mn,
485 const struct mmu_notifier_range *range,
486 unsigned long cur_seq)
487{
488 struct gntdev_grant_map *map =
489 container_of(mn, struct gntdev_grant_map, notifier);
490 unsigned long mstart, mend;
491 int err;
492
493 if (!mmu_notifier_range_blockable(range))
494 return false;
495
496 /*
497 * If the VMA is split or otherwise changed the notifier is not
498 * updated, but we don't want to process VA's outside the modified
499 * VMA. FIXME: It would be much more understandable to just prevent
500 * modifying the VMA in the first place.
501 */
502 if (map->vma->vm_start >= range->end ||
503 map->vma->vm_end <= range->start)
504 return true;
505
506 mstart = max(range->start, map->vma->vm_start);
507 mend = min(range->end, map->vma->vm_end);
508 pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n",
509 map->index, map->count,
510 map->vma->vm_start, map->vma->vm_end,
511 range->start, range->end, mstart, mend);
512 err = unmap_grant_pages(map,
513 (mstart - map->vma->vm_start) >> PAGE_SHIFT,
514 (mend - mstart) >> PAGE_SHIFT);
515 WARN_ON(err);
516
517 return true;
518}
519
520static const struct mmu_interval_notifier_ops gntdev_mmu_ops = {
521 .invalidate = gntdev_invalidate,
522};
523
524/* ------------------------------------------------------------------ */
525
526static int gntdev_open(struct inode *inode, struct file *flip)
527{
528 struct gntdev_priv *priv;
529
530 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
531 if (!priv)
532 return -ENOMEM;
533
534 INIT_LIST_HEAD(&priv->maps);
535 mutex_init(&priv->lock);
536
537#ifdef CONFIG_XEN_GNTDEV_DMABUF
538 priv->dmabuf_priv = gntdev_dmabuf_init(flip);
539 if (IS_ERR(priv->dmabuf_priv)) {
540 int ret = PTR_ERR(priv->dmabuf_priv);
541
542 kfree(priv);
543 return ret;
544 }
545#endif
546
547 flip->private_data = priv;
548#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
549 priv->dma_dev = gntdev_miscdev.this_device;
550 dma_coerce_mask_and_coherent(priv->dma_dev, DMA_BIT_MASK(64));
551#endif
552 pr_debug("priv %p\n", priv);
553
554 return 0;
555}
556
557static int gntdev_release(struct inode *inode, struct file *flip)
558{
559 struct gntdev_priv *priv = flip->private_data;
560 struct gntdev_grant_map *map;
561
562 pr_debug("priv %p\n", priv);
563
564 mutex_lock(&priv->lock);
565 while (!list_empty(&priv->maps)) {
566 map = list_entry(priv->maps.next,
567 struct gntdev_grant_map, next);
568 list_del(&map->next);
569 gntdev_put_map(NULL /* already removed */, map);
570 }
571 mutex_unlock(&priv->lock);
572
573#ifdef CONFIG_XEN_GNTDEV_DMABUF
574 gntdev_dmabuf_fini(priv->dmabuf_priv);
575#endif
576
577 kfree(priv);
578 return 0;
579}
580
581static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv,
582 struct ioctl_gntdev_map_grant_ref __user *u)
583{
584 struct ioctl_gntdev_map_grant_ref op;
585 struct gntdev_grant_map *map;
586 int err;
587
588 if (copy_from_user(&op, u, sizeof(op)) != 0)
589 return -EFAULT;
590 pr_debug("priv %p, add %d\n", priv, op.count);
591 if (unlikely(gntdev_test_page_count(op.count)))
592 return -EINVAL;
593
594 err = -ENOMEM;
595 map = gntdev_alloc_map(priv, op.count, 0 /* This is not a dma-buf. */);
596 if (!map)
597 return err;
598
599 if (copy_from_user(map->grants, &u->refs,
600 sizeof(map->grants[0]) * op.count) != 0) {
601 gntdev_put_map(NULL, map);
602 return -EFAULT;
603 }
604
605 mutex_lock(&priv->lock);
606 gntdev_add_map(priv, map);
607 op.index = map->index << PAGE_SHIFT;
608 mutex_unlock(&priv->lock);
609
610 if (copy_to_user(u, &op, sizeof(op)) != 0)
611 return -EFAULT;
612
613 return 0;
614}
615
616static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv *priv,
617 struct ioctl_gntdev_unmap_grant_ref __user *u)
618{
619 struct ioctl_gntdev_unmap_grant_ref op;
620 struct gntdev_grant_map *map;
621 int err = -ENOENT;
622
623 if (copy_from_user(&op, u, sizeof(op)) != 0)
624 return -EFAULT;
625 pr_debug("priv %p, del %d+%d\n", priv, (int)op.index, (int)op.count);
626
627 mutex_lock(&priv->lock);
628 map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count);
629 if (map) {
630 list_del(&map->next);
631 err = 0;
632 }
633 mutex_unlock(&priv->lock);
634 if (map)
635 gntdev_put_map(priv, map);
636 return err;
637}
638
639static long gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv *priv,
640 struct ioctl_gntdev_get_offset_for_vaddr __user *u)
641{
642 struct ioctl_gntdev_get_offset_for_vaddr op;
643 struct vm_area_struct *vma;
644 struct gntdev_grant_map *map;
645 int rv = -EINVAL;
646
647 if (copy_from_user(&op, u, sizeof(op)) != 0)
648 return -EFAULT;
649 pr_debug("priv %p, offset for vaddr %lx\n", priv, (unsigned long)op.vaddr);
650
651 mmap_read_lock(current->mm);
652 vma = find_vma(current->mm, op.vaddr);
653 if (!vma || vma->vm_ops != &gntdev_vmops)
654 goto out_unlock;
655
656 map = vma->vm_private_data;
657 if (!map)
658 goto out_unlock;
659
660 op.offset = map->index << PAGE_SHIFT;
661 op.count = map->count;
662 rv = 0;
663
664 out_unlock:
665 mmap_read_unlock(current->mm);
666
667 if (rv == 0 && copy_to_user(u, &op, sizeof(op)) != 0)
668 return -EFAULT;
669 return rv;
670}
671
672static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u)
673{
674 struct ioctl_gntdev_unmap_notify op;
675 struct gntdev_grant_map *map;
676 int rc;
677 int out_flags;
678 evtchn_port_t out_event;
679
680 if (copy_from_user(&op, u, sizeof(op)))
681 return -EFAULT;
682
683 if (op.action & ~(UNMAP_NOTIFY_CLEAR_BYTE|UNMAP_NOTIFY_SEND_EVENT))
684 return -EINVAL;
685
686 /* We need to grab a reference to the event channel we are going to use
687 * to send the notify before releasing the reference we may already have
688 * (if someone has called this ioctl twice). This is required so that
689 * it is possible to change the clear_byte part of the notification
690 * without disturbing the event channel part, which may now be the last
691 * reference to that event channel.
692 */
693 if (op.action & UNMAP_NOTIFY_SEND_EVENT) {
694 if (evtchn_get(op.event_channel_port))
695 return -EINVAL;
696 }
697
698 out_flags = op.action;
699 out_event = op.event_channel_port;
700
701 mutex_lock(&priv->lock);
702
703 list_for_each_entry(map, &priv->maps, next) {
704 uint64_t begin = map->index << PAGE_SHIFT;
705 uint64_t end = (map->index + map->count) << PAGE_SHIFT;
706 if (op.index >= begin && op.index < end)
707 goto found;
708 }
709 rc = -ENOENT;
710 goto unlock_out;
711
712 found:
713 if ((op.action & UNMAP_NOTIFY_CLEAR_BYTE) &&
714 (map->flags & GNTMAP_readonly)) {
715 rc = -EINVAL;
716 goto unlock_out;
717 }
718
719 out_flags = map->notify.flags;
720 out_event = map->notify.event;
721
722 map->notify.flags = op.action;
723 map->notify.addr = op.index - (map->index << PAGE_SHIFT);
724 map->notify.event = op.event_channel_port;
725
726 rc = 0;
727
728 unlock_out:
729 mutex_unlock(&priv->lock);
730
731 /* Drop the reference to the event channel we did not save in the map */
732 if (out_flags & UNMAP_NOTIFY_SEND_EVENT)
733 evtchn_put(out_event);
734
735 return rc;
736}
737
738#define GNTDEV_COPY_BATCH 16
739
740struct gntdev_copy_batch {
741 struct gnttab_copy ops[GNTDEV_COPY_BATCH];
742 struct page *pages[GNTDEV_COPY_BATCH];
743 s16 __user *status[GNTDEV_COPY_BATCH];
744 unsigned int nr_ops;
745 unsigned int nr_pages;
746 bool writeable;
747};
748
749static int gntdev_get_page(struct gntdev_copy_batch *batch, void __user *virt,
750 unsigned long *gfn)
751{
752 unsigned long addr = (unsigned long)virt;
753 struct page *page;
754 unsigned long xen_pfn;
755 int ret;
756
757 ret = pin_user_pages_fast(addr, 1, batch->writeable ? FOLL_WRITE : 0, &page);
758 if (ret < 0)
759 return ret;
760
761 batch->pages[batch->nr_pages++] = page;
762
763 xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(addr & ~PAGE_MASK);
764 *gfn = pfn_to_gfn(xen_pfn);
765
766 return 0;
767}
768
769static void gntdev_put_pages(struct gntdev_copy_batch *batch)
770{
771 unpin_user_pages_dirty_lock(batch->pages, batch->nr_pages, batch->writeable);
772 batch->nr_pages = 0;
773 batch->writeable = false;
774}
775
776static int gntdev_copy(struct gntdev_copy_batch *batch)
777{
778 unsigned int i;
779
780 gnttab_batch_copy(batch->ops, batch->nr_ops);
781 gntdev_put_pages(batch);
782
783 /*
784 * For each completed op, update the status if the op failed
785 * and all previous ops for the segment were successful.
786 */
787 for (i = 0; i < batch->nr_ops; i++) {
788 s16 status = batch->ops[i].status;
789 s16 old_status;
790
791 if (status == GNTST_okay)
792 continue;
793
794 if (__get_user(old_status, batch->status[i]))
795 return -EFAULT;
796
797 if (old_status != GNTST_okay)
798 continue;
799
800 if (__put_user(status, batch->status[i]))
801 return -EFAULT;
802 }
803
804 batch->nr_ops = 0;
805 return 0;
806}
807
808static int gntdev_grant_copy_seg(struct gntdev_copy_batch *batch,
809 struct gntdev_grant_copy_segment *seg,
810 s16 __user *status)
811{
812 uint16_t copied = 0;
813
814 /*
815 * Disallow local -> local copies since there is only space in
816 * batch->pages for one page per-op and this would be a very
817 * expensive memcpy().
818 */
819 if (!(seg->flags & (GNTCOPY_source_gref | GNTCOPY_dest_gref)))
820 return -EINVAL;
821
822 /* Can't cross page if source/dest is a grant ref. */
823 if (seg->flags & GNTCOPY_source_gref) {
824 if (seg->source.foreign.offset + seg->len > XEN_PAGE_SIZE)
825 return -EINVAL;
826 }
827 if (seg->flags & GNTCOPY_dest_gref) {
828 if (seg->dest.foreign.offset + seg->len > XEN_PAGE_SIZE)
829 return -EINVAL;
830 }
831
832 if (put_user(GNTST_okay, status))
833 return -EFAULT;
834
835 while (copied < seg->len) {
836 struct gnttab_copy *op;
837 void __user *virt;
838 size_t len, off;
839 unsigned long gfn;
840 int ret;
841
842 if (batch->nr_ops >= GNTDEV_COPY_BATCH) {
843 ret = gntdev_copy(batch);
844 if (ret < 0)
845 return ret;
846 }
847
848 len = seg->len - copied;
849
850 op = &batch->ops[batch->nr_ops];
851 op->flags = 0;
852
853 if (seg->flags & GNTCOPY_source_gref) {
854 op->source.u.ref = seg->source.foreign.ref;
855 op->source.domid = seg->source.foreign.domid;
856 op->source.offset = seg->source.foreign.offset + copied;
857 op->flags |= GNTCOPY_source_gref;
858 } else {
859 virt = seg->source.virt + copied;
860 off = (unsigned long)virt & ~XEN_PAGE_MASK;
861 len = min(len, (size_t)XEN_PAGE_SIZE - off);
862 batch->writeable = false;
863
864 ret = gntdev_get_page(batch, virt, &gfn);
865 if (ret < 0)
866 return ret;
867
868 op->source.u.gmfn = gfn;
869 op->source.domid = DOMID_SELF;
870 op->source.offset = off;
871 }
872
873 if (seg->flags & GNTCOPY_dest_gref) {
874 op->dest.u.ref = seg->dest.foreign.ref;
875 op->dest.domid = seg->dest.foreign.domid;
876 op->dest.offset = seg->dest.foreign.offset + copied;
877 op->flags |= GNTCOPY_dest_gref;
878 } else {
879 virt = seg->dest.virt + copied;
880 off = (unsigned long)virt & ~XEN_PAGE_MASK;
881 len = min(len, (size_t)XEN_PAGE_SIZE - off);
882 batch->writeable = true;
883
884 ret = gntdev_get_page(batch, virt, &gfn);
885 if (ret < 0)
886 return ret;
887
888 op->dest.u.gmfn = gfn;
889 op->dest.domid = DOMID_SELF;
890 op->dest.offset = off;
891 }
892
893 op->len = len;
894 copied += len;
895
896 batch->status[batch->nr_ops] = status;
897 batch->nr_ops++;
898 }
899
900 return 0;
901}
902
903static long gntdev_ioctl_grant_copy(struct gntdev_priv *priv, void __user *u)
904{
905 struct ioctl_gntdev_grant_copy copy;
906 struct gntdev_copy_batch batch;
907 unsigned int i;
908 int ret = 0;
909
910 if (copy_from_user(©, u, sizeof(copy)))
911 return -EFAULT;
912
913 batch.nr_ops = 0;
914 batch.nr_pages = 0;
915
916 for (i = 0; i < copy.count; i++) {
917 struct gntdev_grant_copy_segment seg;
918
919 if (copy_from_user(&seg, ©.segments[i], sizeof(seg))) {
920 ret = -EFAULT;
921 goto out;
922 }
923
924 ret = gntdev_grant_copy_seg(&batch, &seg, ©.segments[i].status);
925 if (ret < 0)
926 goto out;
927
928 cond_resched();
929 }
930 if (batch.nr_ops)
931 ret = gntdev_copy(&batch);
932 return ret;
933
934 out:
935 gntdev_put_pages(&batch);
936 return ret;
937}
938
939static long gntdev_ioctl(struct file *flip,
940 unsigned int cmd, unsigned long arg)
941{
942 struct gntdev_priv *priv = flip->private_data;
943 void __user *ptr = (void __user *)arg;
944
945 switch (cmd) {
946 case IOCTL_GNTDEV_MAP_GRANT_REF:
947 return gntdev_ioctl_map_grant_ref(priv, ptr);
948
949 case IOCTL_GNTDEV_UNMAP_GRANT_REF:
950 return gntdev_ioctl_unmap_grant_ref(priv, ptr);
951
952 case IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR:
953 return gntdev_ioctl_get_offset_for_vaddr(priv, ptr);
954
955 case IOCTL_GNTDEV_SET_UNMAP_NOTIFY:
956 return gntdev_ioctl_notify(priv, ptr);
957
958 case IOCTL_GNTDEV_GRANT_COPY:
959 return gntdev_ioctl_grant_copy(priv, ptr);
960
961#ifdef CONFIG_XEN_GNTDEV_DMABUF
962 case IOCTL_GNTDEV_DMABUF_EXP_FROM_REFS:
963 return gntdev_ioctl_dmabuf_exp_from_refs(priv, use_ptemod, ptr);
964
965 case IOCTL_GNTDEV_DMABUF_EXP_WAIT_RELEASED:
966 return gntdev_ioctl_dmabuf_exp_wait_released(priv, ptr);
967
968 case IOCTL_GNTDEV_DMABUF_IMP_TO_REFS:
969 return gntdev_ioctl_dmabuf_imp_to_refs(priv, ptr);
970
971 case IOCTL_GNTDEV_DMABUF_IMP_RELEASE:
972 return gntdev_ioctl_dmabuf_imp_release(priv, ptr);
973#endif
974
975 default:
976 pr_debug("priv %p, unknown cmd %x\n", priv, cmd);
977 return -ENOIOCTLCMD;
978 }
979
980 return 0;
981}
982
983static 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 gntdev_grant_map *map;
989 int 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 refcount_inc(&map->users);
1004
1005 vma->vm_ops = &gntdev_vmops;
1006
1007 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP | VM_MIXEDMAP;
1008
1009 if (use_ptemod)
1010 vma->vm_flags |= VM_DONTCOPY;
1011
1012 vma->vm_private_data = map;
1013 if (map->flags) {
1014 if ((vma->vm_flags & VM_WRITE) &&
1015 (map->flags & GNTMAP_readonly))
1016 goto out_unlock_put;
1017 } else {
1018 map->flags = GNTMAP_host_map;
1019 if (!(vma->vm_flags & VM_WRITE))
1020 map->flags |= GNTMAP_readonly;
1021 }
1022
1023 if (use_ptemod) {
1024 map->vma = vma;
1025 err = mmu_interval_notifier_insert_locked(
1026 &map->notifier, vma->vm_mm, vma->vm_start,
1027 vma->vm_end - vma->vm_start, &gntdev_mmu_ops);
1028 if (err) {
1029 map->vma = NULL;
1030 goto out_unlock_put;
1031 }
1032 }
1033 mutex_unlock(&priv->lock);
1034
1035 if (use_ptemod) {
1036 /*
1037 * gntdev takes the address of the PTE in find_grant_ptes() and
1038 * passes it to the hypervisor in gntdev_map_grant_pages(). The
1039 * purpose of the notifier is to prevent the hypervisor pointer
1040 * to the PTE from going stale.
1041 *
1042 * Since this vma's mappings can't be touched without the
1043 * mmap_lock, and we are holding it now, there is no need for
1044 * the notifier_range locking pattern.
1045 */
1046 mmu_interval_read_begin(&map->notifier);
1047
1048 map->pages_vm_start = vma->vm_start;
1049 err = apply_to_page_range(vma->vm_mm, vma->vm_start,
1050 vma->vm_end - vma->vm_start,
1051 find_grant_ptes, map);
1052 if (err) {
1053 pr_warn("find_grant_ptes() failure.\n");
1054 goto out_put_map;
1055 }
1056 }
1057
1058 err = gntdev_map_grant_pages(map);
1059 if (err)
1060 goto out_put_map;
1061
1062 if (!use_ptemod) {
1063 err = vm_map_pages_zero(vma, map->pages, map->count);
1064 if (err)
1065 goto out_put_map;
1066 } else {
1067#ifdef CONFIG_X86
1068 /*
1069 * If the PTEs were not made special by the grant map
1070 * hypercall, do so here.
1071 *
1072 * This is racy since the mapping is already visible
1073 * to userspace but userspace should be well-behaved
1074 * enough to not touch it until the mmap() call
1075 * returns.
1076 */
1077 if (!xen_feature(XENFEAT_gnttab_map_avail_bits)) {
1078 apply_to_page_range(vma->vm_mm, vma->vm_start,
1079 vma->vm_end - vma->vm_start,
1080 set_grant_ptes_as_special, NULL);
1081 }
1082#endif
1083 }
1084
1085 return 0;
1086
1087unlock_out:
1088 mutex_unlock(&priv->lock);
1089 return err;
1090
1091out_unlock_put:
1092 mutex_unlock(&priv->lock);
1093out_put_map:
1094 if (use_ptemod) {
1095 unmap_grant_pages(map, 0, map->count);
1096 if (map->vma) {
1097 mmu_interval_notifier_remove(&map->notifier);
1098 map->vma = NULL;
1099 }
1100 }
1101 gntdev_put_map(priv, map);
1102 return err;
1103}
1104
1105static const struct file_operations gntdev_fops = {
1106 .owner = THIS_MODULE,
1107 .open = gntdev_open,
1108 .release = gntdev_release,
1109 .mmap = gntdev_mmap,
1110 .unlocked_ioctl = gntdev_ioctl
1111};
1112
1113static struct miscdevice gntdev_miscdev = {
1114 .minor = MISC_DYNAMIC_MINOR,
1115 .name = "xen/gntdev",
1116 .fops = &gntdev_fops,
1117};
1118
1119/* ------------------------------------------------------------------ */
1120
1121static int __init gntdev_init(void)
1122{
1123 int err;
1124
1125 if (!xen_domain())
1126 return -ENODEV;
1127
1128 use_ptemod = !xen_feature(XENFEAT_auto_translated_physmap);
1129
1130 err = misc_register(&gntdev_miscdev);
1131 if (err != 0) {
1132 pr_err("Could not register gntdev device\n");
1133 return err;
1134 }
1135 return 0;
1136}
1137
1138static void __exit gntdev_exit(void)
1139{
1140 misc_deregister(&gntdev_miscdev);
1141}
1142
1143module_init(gntdev_init);
1144module_exit(gntdev_exit);
1145
1146/* ------------------------------------------------------------------ */