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/module.h> |
26 | #include <linux/kernel.h> |
27 | #include <linux/init.h> |
28 | #include <linux/miscdevice.h> |
29 | #include <linux/fs.h> |
30 | #include <linux/uaccess.h> |
31 | #include <linux/sched.h> |
32 | #include <linux/sched/mm.h> |
33 | #include <linux/spinlock.h> |
34 | #include <linux/slab.h> |
35 | #include <linux/highmem.h> |
36 | #include <linux/refcount.h> |
37 | #ifdef CONFIG_XEN_GRANT_DMA_ALLOC |
38 | #include <linux/of_device.h> |
39 | #endif |
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 | #include "gntdev-common.h" |
51 | #ifdef CONFIG_XEN_GNTDEV_DMABUF |
52 | #include "gntdev-dmabuf.h" |
53 | #endif |
54 | |
55 | MODULE_LICENSE("GPL" ); |
56 | MODULE_AUTHOR("Derek G. Murray <Derek.Murray@cl.cam.ac.uk>, " |
57 | "Gerd Hoffmann <kraxel@redhat.com>" ); |
58 | MODULE_DESCRIPTION("User-space granted page access driver" ); |
59 | |
60 | static int limit = 1024*1024; |
61 | module_param(limit, int, 0644); |
62 | MODULE_PARM_DESC(limit, "Maximum number of grants that may be mapped by " |
63 | "the gntdev device" ); |
64 | |
65 | static atomic_t pages_mapped = ATOMIC_INIT(0); |
66 | |
67 | static int use_ptemod; |
68 | #define populate_freeable_maps use_ptemod |
69 | |
70 | static int unmap_grant_pages(struct gntdev_grant_map *map, |
71 | int offset, int pages); |
72 | |
73 | static struct miscdevice gntdev_miscdev; |
74 | |
75 | /* ------------------------------------------------------------------ */ |
76 | |
77 | bool gntdev_account_mapped_pages(int count) |
78 | { |
79 | return atomic_add_return(count, &pages_mapped) > limit; |
80 | } |
81 | |
82 | static void gntdev_print_maps(struct gntdev_priv *priv, |
83 | char *text, int text_index) |
84 | { |
85 | #ifdef DEBUG |
86 | struct gntdev_grant_map *map; |
87 | |
88 | pr_debug("%s: maps list (priv %p)\n" , __func__, priv); |
89 | list_for_each_entry(map, &priv->maps, next) |
90 | pr_debug(" index %2d, count %2d %s\n" , |
91 | map->index, map->count, |
92 | map->index == text_index && text ? text : "" ); |
93 | #endif |
94 | } |
95 | |
96 | static void gntdev_free_map(struct gntdev_grant_map *map) |
97 | { |
98 | if (map == NULL) |
99 | return; |
100 | |
101 | #ifdef CONFIG_XEN_GRANT_DMA_ALLOC |
102 | if (map->dma_vaddr) { |
103 | struct gnttab_dma_alloc_args args; |
104 | |
105 | args.dev = map->dma_dev; |
106 | args.coherent = !!(map->dma_flags & GNTDEV_DMA_FLAG_COHERENT); |
107 | args.nr_pages = map->count; |
108 | args.pages = map->pages; |
109 | args.frames = map->frames; |
110 | args.vaddr = map->dma_vaddr; |
111 | args.dev_bus_addr = map->dma_bus_addr; |
112 | |
113 | gnttab_dma_free_pages(&args); |
114 | } else |
115 | #endif |
116 | if (map->pages) |
117 | gnttab_free_pages(map->count, map->pages); |
118 | |
119 | #ifdef CONFIG_XEN_GRANT_DMA_ALLOC |
120 | kfree(map->frames); |
121 | #endif |
122 | kfree(map->pages); |
123 | kfree(map->grants); |
124 | kfree(map->map_ops); |
125 | kfree(map->unmap_ops); |
126 | kfree(map->kmap_ops); |
127 | kfree(map->kunmap_ops); |
128 | kfree(map); |
129 | } |
130 | |
131 | struct gntdev_grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count, |
132 | int dma_flags) |
133 | { |
134 | struct gntdev_grant_map *add; |
135 | int i; |
136 | |
137 | add = kzalloc(sizeof(*add), GFP_KERNEL); |
138 | if (NULL == add) |
139 | return NULL; |
140 | |
141 | add->grants = kcalloc(count, sizeof(add->grants[0]), GFP_KERNEL); |
142 | add->map_ops = kcalloc(count, sizeof(add->map_ops[0]), GFP_KERNEL); |
143 | add->unmap_ops = kcalloc(count, sizeof(add->unmap_ops[0]), GFP_KERNEL); |
144 | add->kmap_ops = kcalloc(count, sizeof(add->kmap_ops[0]), GFP_KERNEL); |
145 | add->kunmap_ops = kcalloc(count, sizeof(add->kunmap_ops[0]), GFP_KERNEL); |
146 | add->pages = kcalloc(count, sizeof(add->pages[0]), GFP_KERNEL); |
147 | if (NULL == add->grants || |
148 | NULL == add->map_ops || |
149 | NULL == add->unmap_ops || |
150 | NULL == add->kmap_ops || |
151 | NULL == add->kunmap_ops || |
152 | NULL == add->pages) |
153 | goto err; |
154 | |
155 | #ifdef CONFIG_XEN_GRANT_DMA_ALLOC |
156 | add->dma_flags = dma_flags; |
157 | |
158 | /* |
159 | * Check if this mapping is requested to be backed |
160 | * by a DMA buffer. |
161 | */ |
162 | if (dma_flags & (GNTDEV_DMA_FLAG_WC | GNTDEV_DMA_FLAG_COHERENT)) { |
163 | struct gnttab_dma_alloc_args args; |
164 | |
165 | add->frames = kcalloc(count, sizeof(add->frames[0]), |
166 | GFP_KERNEL); |
167 | if (!add->frames) |
168 | goto err; |
169 | |
170 | /* Remember the device, so we can free DMA memory. */ |
171 | add->dma_dev = priv->dma_dev; |
172 | |
173 | args.dev = priv->dma_dev; |
174 | args.coherent = !!(dma_flags & GNTDEV_DMA_FLAG_COHERENT); |
175 | args.nr_pages = count; |
176 | args.pages = add->pages; |
177 | args.frames = add->frames; |
178 | |
179 | if (gnttab_dma_alloc_pages(&args)) |
180 | goto err; |
181 | |
182 | add->dma_vaddr = args.vaddr; |
183 | add->dma_bus_addr = args.dev_bus_addr; |
184 | } else |
185 | #endif |
186 | if (gnttab_alloc_pages(count, add->pages)) |
187 | goto err; |
188 | |
189 | for (i = 0; i < count; i++) { |
190 | add->map_ops[i].handle = -1; |
191 | add->unmap_ops[i].handle = -1; |
192 | add->kmap_ops[i].handle = -1; |
193 | add->kunmap_ops[i].handle = -1; |
194 | } |
195 | |
196 | add->index = 0; |
197 | add->count = count; |
198 | refcount_set(&add->users, 1); |
199 | |
200 | return add; |
201 | |
202 | err: |
203 | gntdev_free_map(add); |
204 | return NULL; |
205 | } |
206 | |
207 | void gntdev_add_map(struct gntdev_priv *priv, struct gntdev_grant_map *add) |
208 | { |
209 | struct gntdev_grant_map *map; |
210 | |
211 | list_for_each_entry(map, &priv->maps, next) { |
212 | if (add->index + add->count < map->index) { |
213 | list_add_tail(&add->next, &map->next); |
214 | goto done; |
215 | } |
216 | add->index = map->index + map->count; |
217 | } |
218 | list_add_tail(&add->next, &priv->maps); |
219 | |
220 | done: |
221 | gntdev_print_maps(priv, "[new]" , add->index); |
222 | } |
223 | |
224 | static struct gntdev_grant_map *gntdev_find_map_index(struct gntdev_priv *priv, |
225 | int index, int count) |
226 | { |
227 | struct gntdev_grant_map *map; |
228 | |
229 | list_for_each_entry(map, &priv->maps, next) { |
230 | if (map->index != index) |
231 | continue; |
232 | if (count && map->count != count) |
233 | continue; |
234 | return map; |
235 | } |
236 | return NULL; |
237 | } |
238 | |
239 | void gntdev_put_map(struct gntdev_priv *priv, struct gntdev_grant_map *map) |
240 | { |
241 | if (!map) |
242 | return; |
243 | |
244 | if (!refcount_dec_and_test(&map->users)) |
245 | return; |
246 | |
247 | atomic_sub(map->count, &pages_mapped); |
248 | |
249 | if (map->notify.flags & UNMAP_NOTIFY_SEND_EVENT) { |
250 | notify_remote_via_evtchn(map->notify.event); |
251 | evtchn_put(map->notify.event); |
252 | } |
253 | |
254 | if (populate_freeable_maps && priv) { |
255 | mutex_lock(&priv->lock); |
256 | list_del(&map->next); |
257 | mutex_unlock(&priv->lock); |
258 | } |
259 | |
260 | if (map->pages && !use_ptemod) |
261 | unmap_grant_pages(map, 0, map->count); |
262 | gntdev_free_map(map); |
263 | } |
264 | |
265 | /* ------------------------------------------------------------------ */ |
266 | |
267 | static int find_grant_ptes(pte_t *pte, pgtable_t token, |
268 | unsigned long addr, void *data) |
269 | { |
270 | struct gntdev_grant_map *map = data; |
271 | unsigned int pgnr = (addr - map->vma->vm_start) >> PAGE_SHIFT; |
272 | int flags = map->flags | GNTMAP_application_map | GNTMAP_contains_pte; |
273 | u64 pte_maddr; |
274 | |
275 | BUG_ON(pgnr >= map->count); |
276 | pte_maddr = arbitrary_virt_to_machine(pte).maddr; |
277 | |
278 | /* |
279 | * Set the PTE as special to force get_user_pages_fast() fall |
280 | * back to the slow path. If this is not supported as part of |
281 | * the grant map, it will be done afterwards. |
282 | */ |
283 | if (xen_feature(XENFEAT_gnttab_map_avail_bits)) |
284 | flags |= (1 << _GNTMAP_guest_avail0); |
285 | |
286 | gnttab_set_map_op(&map->map_ops[pgnr], pte_maddr, flags, |
287 | map->grants[pgnr].ref, |
288 | map->grants[pgnr].domid); |
289 | gnttab_set_unmap_op(&map->unmap_ops[pgnr], pte_maddr, flags, |
290 | -1 /* handle */); |
291 | return 0; |
292 | } |
293 | |
294 | #ifdef CONFIG_X86 |
295 | static int set_grant_ptes_as_special(pte_t *pte, pgtable_t token, |
296 | unsigned long addr, void *data) |
297 | { |
298 | set_pte_at(current->mm, addr, pte, pte_mkspecial(*pte)); |
299 | return 0; |
300 | } |
301 | #endif |
302 | |
303 | int gntdev_map_grant_pages(struct gntdev_grant_map *map) |
304 | { |
305 | int i, err = 0; |
306 | |
307 | if (!use_ptemod) { |
308 | /* Note: it could already be mapped */ |
309 | if (map->map_ops[0].handle != -1) |
310 | return 0; |
311 | for (i = 0; i < map->count; i++) { |
312 | unsigned long addr = (unsigned long) |
313 | pfn_to_kaddr(page_to_pfn(map->pages[i])); |
314 | gnttab_set_map_op(&map->map_ops[i], addr, map->flags, |
315 | map->grants[i].ref, |
316 | map->grants[i].domid); |
317 | gnttab_set_unmap_op(&map->unmap_ops[i], addr, |
318 | map->flags, -1 /* handle */); |
319 | } |
320 | } else { |
321 | /* |
322 | * Setup the map_ops corresponding to the pte entries pointing |
323 | * to the kernel linear addresses of the struct pages. |
324 | * These ptes are completely different from the user ptes dealt |
325 | * with find_grant_ptes. |
326 | */ |
327 | for (i = 0; i < map->count; i++) { |
328 | unsigned long address = (unsigned long) |
329 | pfn_to_kaddr(page_to_pfn(map->pages[i])); |
330 | BUG_ON(PageHighMem(map->pages[i])); |
331 | |
332 | gnttab_set_map_op(&map->kmap_ops[i], address, |
333 | map->flags | GNTMAP_host_map, |
334 | map->grants[i].ref, |
335 | map->grants[i].domid); |
336 | gnttab_set_unmap_op(&map->kunmap_ops[i], address, |
337 | map->flags | GNTMAP_host_map, -1); |
338 | } |
339 | } |
340 | |
341 | pr_debug("map %d+%d\n" , map->index, map->count); |
342 | err = gnttab_map_refs(map->map_ops, use_ptemod ? map->kmap_ops : NULL, |
343 | map->pages, map->count); |
344 | if (err) |
345 | return err; |
346 | |
347 | for (i = 0; i < map->count; i++) { |
348 | if (map->map_ops[i].status) { |
349 | err = -EINVAL; |
350 | continue; |
351 | } |
352 | |
353 | map->unmap_ops[i].handle = map->map_ops[i].handle; |
354 | if (use_ptemod) |
355 | map->kunmap_ops[i].handle = map->kmap_ops[i].handle; |
356 | #ifdef CONFIG_XEN_GRANT_DMA_ALLOC |
357 | else if (map->dma_vaddr) { |
358 | unsigned long bfn; |
359 | |
360 | bfn = pfn_to_bfn(page_to_pfn(map->pages[i])); |
361 | map->unmap_ops[i].dev_bus_addr = __pfn_to_phys(bfn); |
362 | } |
363 | #endif |
364 | } |
365 | return err; |
366 | } |
367 | |
368 | static int __unmap_grant_pages(struct gntdev_grant_map *map, int offset, |
369 | int pages) |
370 | { |
371 | int i, err = 0; |
372 | struct gntab_unmap_queue_data unmap_data; |
373 | |
374 | if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) { |
375 | int pgno = (map->notify.addr >> PAGE_SHIFT); |
376 | if (pgno >= offset && pgno < offset + pages) { |
377 | /* No need for kmap, pages are in lowmem */ |
378 | uint8_t *tmp = pfn_to_kaddr(page_to_pfn(map->pages[pgno])); |
379 | tmp[map->notify.addr & (PAGE_SIZE-1)] = 0; |
380 | map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE; |
381 | } |
382 | } |
383 | |
384 | unmap_data.unmap_ops = map->unmap_ops + offset; |
385 | unmap_data.kunmap_ops = use_ptemod ? map->kunmap_ops + offset : NULL; |
386 | unmap_data.pages = map->pages + offset; |
387 | unmap_data.count = pages; |
388 | |
389 | err = gnttab_unmap_refs_sync(&unmap_data); |
390 | if (err) |
391 | return err; |
392 | |
393 | for (i = 0; i < pages; i++) { |
394 | if (map->unmap_ops[offset+i].status) |
395 | err = -EINVAL; |
396 | pr_debug("unmap handle=%d st=%d\n" , |
397 | map->unmap_ops[offset+i].handle, |
398 | map->unmap_ops[offset+i].status); |
399 | map->unmap_ops[offset+i].handle = -1; |
400 | } |
401 | return err; |
402 | } |
403 | |
404 | static int unmap_grant_pages(struct gntdev_grant_map *map, int offset, |
405 | int pages) |
406 | { |
407 | int range, err = 0; |
408 | |
409 | pr_debug("unmap %d+%d [%d+%d]\n" , map->index, map->count, offset, pages); |
410 | |
411 | /* It is possible the requested range will have a "hole" where we |
412 | * already unmapped some of the grants. Only unmap valid ranges. |
413 | */ |
414 | while (pages && !err) { |
415 | while (pages && map->unmap_ops[offset].handle == -1) { |
416 | offset++; |
417 | pages--; |
418 | } |
419 | range = 0; |
420 | while (range < pages) { |
421 | if (map->unmap_ops[offset+range].handle == -1) |
422 | break; |
423 | range++; |
424 | } |
425 | err = __unmap_grant_pages(map, offset, range); |
426 | offset += range; |
427 | pages -= range; |
428 | } |
429 | |
430 | return err; |
431 | } |
432 | |
433 | /* ------------------------------------------------------------------ */ |
434 | |
435 | static void gntdev_vma_open(struct vm_area_struct *vma) |
436 | { |
437 | struct gntdev_grant_map *map = vma->vm_private_data; |
438 | |
439 | pr_debug("gntdev_vma_open %p\n" , vma); |
440 | refcount_inc(&map->users); |
441 | } |
442 | |
443 | static void gntdev_vma_close(struct vm_area_struct *vma) |
444 | { |
445 | struct gntdev_grant_map *map = vma->vm_private_data; |
446 | struct file *file = vma->vm_file; |
447 | struct gntdev_priv *priv = file->private_data; |
448 | |
449 | pr_debug("gntdev_vma_close %p\n" , vma); |
450 | if (use_ptemod) { |
451 | /* It is possible that an mmu notifier could be running |
452 | * concurrently, so take priv->lock to ensure that the vma won't |
453 | * vanishing during the unmap_grant_pages call, since we will |
454 | * spin here until that completes. Such a concurrent call will |
455 | * not do any unmapping, since that has been done prior to |
456 | * closing the vma, but it may still iterate the unmap_ops list. |
457 | */ |
458 | mutex_lock(&priv->lock); |
459 | map->vma = NULL; |
460 | mutex_unlock(&priv->lock); |
461 | } |
462 | vma->vm_private_data = NULL; |
463 | gntdev_put_map(priv, map); |
464 | } |
465 | |
466 | static struct page *gntdev_vma_find_special_page(struct vm_area_struct *vma, |
467 | unsigned long addr) |
468 | { |
469 | struct gntdev_grant_map *map = vma->vm_private_data; |
470 | |
471 | return map->pages[(addr - map->pages_vm_start) >> PAGE_SHIFT]; |
472 | } |
473 | |
474 | static const struct vm_operations_struct gntdev_vmops = { |
475 | .open = gntdev_vma_open, |
476 | .close = gntdev_vma_close, |
477 | .find_special_page = gntdev_vma_find_special_page, |
478 | }; |
479 | |
480 | /* ------------------------------------------------------------------ */ |
481 | |
482 | static bool in_range(struct gntdev_grant_map *map, |
483 | unsigned long start, unsigned long end) |
484 | { |
485 | if (!map->vma) |
486 | return false; |
487 | if (map->vma->vm_start >= end) |
488 | return false; |
489 | if (map->vma->vm_end <= start) |
490 | return false; |
491 | |
492 | return true; |
493 | } |
494 | |
495 | static int unmap_if_in_range(struct gntdev_grant_map *map, |
496 | unsigned long start, unsigned long end, |
497 | bool blockable) |
498 | { |
499 | unsigned long mstart, mend; |
500 | int err; |
501 | |
502 | if (!in_range(map, start, end)) |
503 | return 0; |
504 | |
505 | if (!blockable) |
506 | return -EAGAIN; |
507 | |
508 | mstart = max(start, map->vma->vm_start); |
509 | mend = min(end, map->vma->vm_end); |
510 | pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n" , |
511 | map->index, map->count, |
512 | map->vma->vm_start, map->vma->vm_end, |
513 | start, end, mstart, mend); |
514 | err = unmap_grant_pages(map, |
515 | (mstart - map->vma->vm_start) >> PAGE_SHIFT, |
516 | (mend - mstart) >> PAGE_SHIFT); |
517 | WARN_ON(err); |
518 | |
519 | return 0; |
520 | } |
521 | |
522 | static int mn_invl_range_start(struct mmu_notifier *mn, |
523 | const struct mmu_notifier_range *range) |
524 | { |
525 | struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn); |
526 | struct gntdev_grant_map *map; |
527 | int ret = 0; |
528 | |
529 | if (range->blockable) |
530 | mutex_lock(&priv->lock); |
531 | else if (!mutex_trylock(&priv->lock)) |
532 | return -EAGAIN; |
533 | |
534 | list_for_each_entry(map, &priv->maps, next) { |
535 | ret = unmap_if_in_range(map, range->start, range->end, |
536 | range->blockable); |
537 | if (ret) |
538 | goto out_unlock; |
539 | } |
540 | list_for_each_entry(map, &priv->freeable_maps, next) { |
541 | ret = unmap_if_in_range(map, range->start, range->end, |
542 | range->blockable); |
543 | if (ret) |
544 | goto out_unlock; |
545 | } |
546 | |
547 | out_unlock: |
548 | mutex_unlock(&priv->lock); |
549 | |
550 | return ret; |
551 | } |
552 | |
553 | static void mn_release(struct mmu_notifier *mn, |
554 | struct mm_struct *mm) |
555 | { |
556 | struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn); |
557 | struct gntdev_grant_map *map; |
558 | int err; |
559 | |
560 | mutex_lock(&priv->lock); |
561 | list_for_each_entry(map, &priv->maps, next) { |
562 | if (!map->vma) |
563 | continue; |
564 | pr_debug("map %d+%d (%lx %lx)\n" , |
565 | map->index, map->count, |
566 | map->vma->vm_start, map->vma->vm_end); |
567 | err = unmap_grant_pages(map, /* offset */ 0, map->count); |
568 | WARN_ON(err); |
569 | } |
570 | list_for_each_entry(map, &priv->freeable_maps, next) { |
571 | if (!map->vma) |
572 | continue; |
573 | pr_debug("map %d+%d (%lx %lx)\n" , |
574 | map->index, map->count, |
575 | map->vma->vm_start, map->vma->vm_end); |
576 | err = unmap_grant_pages(map, /* offset */ 0, map->count); |
577 | WARN_ON(err); |
578 | } |
579 | mutex_unlock(&priv->lock); |
580 | } |
581 | |
582 | static const struct mmu_notifier_ops gntdev_mmu_ops = { |
583 | .release = mn_release, |
584 | .invalidate_range_start = mn_invl_range_start, |
585 | }; |
586 | |
587 | /* ------------------------------------------------------------------ */ |
588 | |
589 | static int gntdev_open(struct inode *inode, struct file *flip) |
590 | { |
591 | struct gntdev_priv *priv; |
592 | int ret = 0; |
593 | |
594 | priv = kzalloc(sizeof(*priv), GFP_KERNEL); |
595 | if (!priv) |
596 | return -ENOMEM; |
597 | |
598 | INIT_LIST_HEAD(&priv->maps); |
599 | INIT_LIST_HEAD(&priv->freeable_maps); |
600 | mutex_init(&priv->lock); |
601 | |
602 | #ifdef CONFIG_XEN_GNTDEV_DMABUF |
603 | priv->dmabuf_priv = gntdev_dmabuf_init(flip); |
604 | if (IS_ERR(priv->dmabuf_priv)) { |
605 | ret = PTR_ERR(priv->dmabuf_priv); |
606 | kfree(priv); |
607 | return ret; |
608 | } |
609 | #endif |
610 | |
611 | if (use_ptemod) { |
612 | priv->mm = get_task_mm(current); |
613 | if (!priv->mm) { |
614 | kfree(priv); |
615 | return -ENOMEM; |
616 | } |
617 | priv->mn.ops = &gntdev_mmu_ops; |
618 | ret = mmu_notifier_register(&priv->mn, priv->mm); |
619 | mmput(priv->mm); |
620 | } |
621 | |
622 | if (ret) { |
623 | kfree(priv); |
624 | return ret; |
625 | } |
626 | |
627 | flip->private_data = priv; |
628 | #ifdef CONFIG_XEN_GRANT_DMA_ALLOC |
629 | priv->dma_dev = gntdev_miscdev.this_device; |
630 | |
631 | /* |
632 | * The device is not spawn from a device tree, so arch_setup_dma_ops |
633 | * is not called, thus leaving the device with dummy DMA ops. |
634 | * Fix this by calling of_dma_configure() with a NULL node to set |
635 | * default DMA ops. |
636 | */ |
637 | of_dma_configure(priv->dma_dev, NULL, true); |
638 | #endif |
639 | pr_debug("priv %p\n" , priv); |
640 | |
641 | return 0; |
642 | } |
643 | |
644 | static int gntdev_release(struct inode *inode, struct file *flip) |
645 | { |
646 | struct gntdev_priv *priv = flip->private_data; |
647 | struct gntdev_grant_map *map; |
648 | |
649 | pr_debug("priv %p\n" , priv); |
650 | |
651 | mutex_lock(&priv->lock); |
652 | while (!list_empty(&priv->maps)) { |
653 | map = list_entry(priv->maps.next, |
654 | struct gntdev_grant_map, next); |
655 | list_del(&map->next); |
656 | gntdev_put_map(NULL /* already removed */, map); |
657 | } |
658 | WARN_ON(!list_empty(&priv->freeable_maps)); |
659 | mutex_unlock(&priv->lock); |
660 | |
661 | #ifdef CONFIG_XEN_GNTDEV_DMABUF |
662 | gntdev_dmabuf_fini(priv->dmabuf_priv); |
663 | #endif |
664 | |
665 | if (use_ptemod) |
666 | mmu_notifier_unregister(&priv->mn, priv->mm); |
667 | |
668 | kfree(priv); |
669 | return 0; |
670 | } |
671 | |
672 | static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv, |
673 | struct ioctl_gntdev_map_grant_ref __user *u) |
674 | { |
675 | struct ioctl_gntdev_map_grant_ref op; |
676 | struct gntdev_grant_map *map; |
677 | int err; |
678 | |
679 | if (copy_from_user(&op, u, sizeof(op)) != 0) |
680 | return -EFAULT; |
681 | pr_debug("priv %p, add %d\n" , priv, op.count); |
682 | if (unlikely(op.count <= 0)) |
683 | return -EINVAL; |
684 | |
685 | err = -ENOMEM; |
686 | map = gntdev_alloc_map(priv, op.count, 0 /* This is not a dma-buf. */); |
687 | if (!map) |
688 | return err; |
689 | |
690 | if (unlikely(gntdev_account_mapped_pages(op.count))) { |
691 | pr_debug("can't map: over limit\n" ); |
692 | gntdev_put_map(NULL, map); |
693 | return err; |
694 | } |
695 | |
696 | if (copy_from_user(map->grants, &u->refs, |
697 | sizeof(map->grants[0]) * op.count) != 0) { |
698 | gntdev_put_map(NULL, map); |
699 | return -EFAULT; |
700 | } |
701 | |
702 | mutex_lock(&priv->lock); |
703 | gntdev_add_map(priv, map); |
704 | op.index = map->index << PAGE_SHIFT; |
705 | mutex_unlock(&priv->lock); |
706 | |
707 | if (copy_to_user(u, &op, sizeof(op)) != 0) |
708 | return -EFAULT; |
709 | |
710 | return 0; |
711 | } |
712 | |
713 | static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv *priv, |
714 | struct ioctl_gntdev_unmap_grant_ref __user *u) |
715 | { |
716 | struct ioctl_gntdev_unmap_grant_ref op; |
717 | struct gntdev_grant_map *map; |
718 | int err = -ENOENT; |
719 | |
720 | if (copy_from_user(&op, u, sizeof(op)) != 0) |
721 | return -EFAULT; |
722 | pr_debug("priv %p, del %d+%d\n" , priv, (int)op.index, (int)op.count); |
723 | |
724 | mutex_lock(&priv->lock); |
725 | map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count); |
726 | if (map) { |
727 | list_del(&map->next); |
728 | if (populate_freeable_maps) |
729 | list_add_tail(&map->next, &priv->freeable_maps); |
730 | err = 0; |
731 | } |
732 | mutex_unlock(&priv->lock); |
733 | if (map) |
734 | gntdev_put_map(priv, map); |
735 | return err; |
736 | } |
737 | |
738 | static long gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv *priv, |
739 | struct ioctl_gntdev_get_offset_for_vaddr __user *u) |
740 | { |
741 | struct ioctl_gntdev_get_offset_for_vaddr op; |
742 | struct vm_area_struct *vma; |
743 | struct gntdev_grant_map *map; |
744 | int rv = -EINVAL; |
745 | |
746 | if (copy_from_user(&op, u, sizeof(op)) != 0) |
747 | return -EFAULT; |
748 | pr_debug("priv %p, offset for vaddr %lx\n" , priv, (unsigned long)op.vaddr); |
749 | |
750 | down_read(¤t->mm->mmap_sem); |
751 | vma = find_vma(current->mm, op.vaddr); |
752 | if (!vma || vma->vm_ops != &gntdev_vmops) |
753 | goto out_unlock; |
754 | |
755 | map = vma->vm_private_data; |
756 | if (!map) |
757 | goto out_unlock; |
758 | |
759 | op.offset = map->index << PAGE_SHIFT; |
760 | op.count = map->count; |
761 | rv = 0; |
762 | |
763 | out_unlock: |
764 | up_read(¤t->mm->mmap_sem); |
765 | |
766 | if (rv == 0 && copy_to_user(u, &op, sizeof(op)) != 0) |
767 | return -EFAULT; |
768 | return rv; |
769 | } |
770 | |
771 | static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u) |
772 | { |
773 | struct ioctl_gntdev_unmap_notify op; |
774 | struct gntdev_grant_map *map; |
775 | int rc; |
776 | int out_flags; |
777 | unsigned int out_event; |
778 | |
779 | if (copy_from_user(&op, u, sizeof(op))) |
780 | return -EFAULT; |
781 | |
782 | if (op.action & ~(UNMAP_NOTIFY_CLEAR_BYTE|UNMAP_NOTIFY_SEND_EVENT)) |
783 | return -EINVAL; |
784 | |
785 | /* We need to grab a reference to the event channel we are going to use |
786 | * to send the notify before releasing the reference we may already have |
787 | * (if someone has called this ioctl twice). This is required so that |
788 | * it is possible to change the clear_byte part of the notification |
789 | * without disturbing the event channel part, which may now be the last |
790 | * reference to that event channel. |
791 | */ |
792 | if (op.action & UNMAP_NOTIFY_SEND_EVENT) { |
793 | if (evtchn_get(op.event_channel_port)) |
794 | return -EINVAL; |
795 | } |
796 | |
797 | out_flags = op.action; |
798 | out_event = op.event_channel_port; |
799 | |
800 | mutex_lock(&priv->lock); |
801 | |
802 | list_for_each_entry(map, &priv->maps, next) { |
803 | uint64_t begin = map->index << PAGE_SHIFT; |
804 | uint64_t end = (map->index + map->count) << PAGE_SHIFT; |
805 | if (op.index >= begin && op.index < end) |
806 | goto found; |
807 | } |
808 | rc = -ENOENT; |
809 | goto unlock_out; |
810 | |
811 | found: |
812 | if ((op.action & UNMAP_NOTIFY_CLEAR_BYTE) && |
813 | (map->flags & GNTMAP_readonly)) { |
814 | rc = -EINVAL; |
815 | goto unlock_out; |
816 | } |
817 | |
818 | out_flags = map->notify.flags; |
819 | out_event = map->notify.event; |
820 | |
821 | map->notify.flags = op.action; |
822 | map->notify.addr = op.index - (map->index << PAGE_SHIFT); |
823 | map->notify.event = op.event_channel_port; |
824 | |
825 | rc = 0; |
826 | |
827 | unlock_out: |
828 | mutex_unlock(&priv->lock); |
829 | |
830 | /* Drop the reference to the event channel we did not save in the map */ |
831 | if (out_flags & UNMAP_NOTIFY_SEND_EVENT) |
832 | evtchn_put(out_event); |
833 | |
834 | return rc; |
835 | } |
836 | |
837 | #define GNTDEV_COPY_BATCH 16 |
838 | |
839 | struct gntdev_copy_batch { |
840 | struct gnttab_copy ops[GNTDEV_COPY_BATCH]; |
841 | struct page *pages[GNTDEV_COPY_BATCH]; |
842 | s16 __user *status[GNTDEV_COPY_BATCH]; |
843 | unsigned int nr_ops; |
844 | unsigned int nr_pages; |
845 | }; |
846 | |
847 | static int gntdev_get_page(struct gntdev_copy_batch *batch, void __user *virt, |
848 | bool writeable, unsigned long *gfn) |
849 | { |
850 | unsigned long addr = (unsigned long)virt; |
851 | struct page *page; |
852 | unsigned long xen_pfn; |
853 | int ret; |
854 | |
855 | ret = get_user_pages_fast(addr, 1, writeable, &page); |
856 | if (ret < 0) |
857 | return ret; |
858 | |
859 | batch->pages[batch->nr_pages++] = page; |
860 | |
861 | xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(addr & ~PAGE_MASK); |
862 | *gfn = pfn_to_gfn(xen_pfn); |
863 | |
864 | return 0; |
865 | } |
866 | |
867 | static void gntdev_put_pages(struct gntdev_copy_batch *batch) |
868 | { |
869 | unsigned int i; |
870 | |
871 | for (i = 0; i < batch->nr_pages; i++) |
872 | put_page(batch->pages[i]); |
873 | batch->nr_pages = 0; |
874 | } |
875 | |
876 | static int gntdev_copy(struct gntdev_copy_batch *batch) |
877 | { |
878 | unsigned int i; |
879 | |
880 | gnttab_batch_copy(batch->ops, batch->nr_ops); |
881 | gntdev_put_pages(batch); |
882 | |
883 | /* |
884 | * For each completed op, update the status if the op failed |
885 | * and all previous ops for the segment were successful. |
886 | */ |
887 | for (i = 0; i < batch->nr_ops; i++) { |
888 | s16 status = batch->ops[i].status; |
889 | s16 old_status; |
890 | |
891 | if (status == GNTST_okay) |
892 | continue; |
893 | |
894 | if (__get_user(old_status, batch->status[i])) |
895 | return -EFAULT; |
896 | |
897 | if (old_status != GNTST_okay) |
898 | continue; |
899 | |
900 | if (__put_user(status, batch->status[i])) |
901 | return -EFAULT; |
902 | } |
903 | |
904 | batch->nr_ops = 0; |
905 | return 0; |
906 | } |
907 | |
908 | static int gntdev_grant_copy_seg(struct gntdev_copy_batch *batch, |
909 | struct gntdev_grant_copy_segment *seg, |
910 | s16 __user *status) |
911 | { |
912 | uint16_t copied = 0; |
913 | |
914 | /* |
915 | * Disallow local -> local copies since there is only space in |
916 | * batch->pages for one page per-op and this would be a very |
917 | * expensive memcpy(). |
918 | */ |
919 | if (!(seg->flags & (GNTCOPY_source_gref | GNTCOPY_dest_gref))) |
920 | return -EINVAL; |
921 | |
922 | /* Can't cross page if source/dest is a grant ref. */ |
923 | if (seg->flags & GNTCOPY_source_gref) { |
924 | if (seg->source.foreign.offset + seg->len > XEN_PAGE_SIZE) |
925 | return -EINVAL; |
926 | } |
927 | if (seg->flags & GNTCOPY_dest_gref) { |
928 | if (seg->dest.foreign.offset + seg->len > XEN_PAGE_SIZE) |
929 | return -EINVAL; |
930 | } |
931 | |
932 | if (put_user(GNTST_okay, status)) |
933 | return -EFAULT; |
934 | |
935 | while (copied < seg->len) { |
936 | struct gnttab_copy *op; |
937 | void __user *virt; |
938 | size_t len, off; |
939 | unsigned long gfn; |
940 | int ret; |
941 | |
942 | if (batch->nr_ops >= GNTDEV_COPY_BATCH) { |
943 | ret = gntdev_copy(batch); |
944 | if (ret < 0) |
945 | return ret; |
946 | } |
947 | |
948 | len = seg->len - copied; |
949 | |
950 | op = &batch->ops[batch->nr_ops]; |
951 | op->flags = 0; |
952 | |
953 | if (seg->flags & GNTCOPY_source_gref) { |
954 | op->source.u.ref = seg->source.foreign.ref; |
955 | op->source.domid = seg->source.foreign.domid; |
956 | op->source.offset = seg->source.foreign.offset + copied; |
957 | op->flags |= GNTCOPY_source_gref; |
958 | } else { |
959 | virt = seg->source.virt + copied; |
960 | off = (unsigned long)virt & ~XEN_PAGE_MASK; |
961 | len = min(len, (size_t)XEN_PAGE_SIZE - off); |
962 | |
963 | ret = gntdev_get_page(batch, virt, false, &gfn); |
964 | if (ret < 0) |
965 | return ret; |
966 | |
967 | op->source.u.gmfn = gfn; |
968 | op->source.domid = DOMID_SELF; |
969 | op->source.offset = off; |
970 | } |
971 | |
972 | if (seg->flags & GNTCOPY_dest_gref) { |
973 | op->dest.u.ref = seg->dest.foreign.ref; |
974 | op->dest.domid = seg->dest.foreign.domid; |
975 | op->dest.offset = seg->dest.foreign.offset + copied; |
976 | op->flags |= GNTCOPY_dest_gref; |
977 | } else { |
978 | virt = seg->dest.virt + copied; |
979 | off = (unsigned long)virt & ~XEN_PAGE_MASK; |
980 | len = min(len, (size_t)XEN_PAGE_SIZE - off); |
981 | |
982 | ret = gntdev_get_page(batch, virt, true, &gfn); |
983 | if (ret < 0) |
984 | return ret; |
985 | |
986 | op->dest.u.gmfn = gfn; |
987 | op->dest.domid = DOMID_SELF; |
988 | op->dest.offset = off; |
989 | } |
990 | |
991 | op->len = len; |
992 | copied += len; |
993 | |
994 | batch->status[batch->nr_ops] = status; |
995 | batch->nr_ops++; |
996 | } |
997 | |
998 | return 0; |
999 | } |
1000 | |
1001 | static long gntdev_ioctl_grant_copy(struct gntdev_priv *priv, void __user *u) |
1002 | { |
1003 | struct ioctl_gntdev_grant_copy copy; |
1004 | struct gntdev_copy_batch batch; |
1005 | unsigned int i; |
1006 | int ret = 0; |
1007 | |
1008 | if (copy_from_user(©, u, sizeof(copy))) |
1009 | return -EFAULT; |
1010 | |
1011 | batch.nr_ops = 0; |
1012 | batch.nr_pages = 0; |
1013 | |
1014 | for (i = 0; i < copy.count; i++) { |
1015 | struct gntdev_grant_copy_segment seg; |
1016 | |
1017 | if (copy_from_user(&seg, ©.segments[i], sizeof(seg))) { |
1018 | ret = -EFAULT; |
1019 | goto out; |
1020 | } |
1021 | |
1022 | ret = gntdev_grant_copy_seg(&batch, &seg, ©.segments[i].status); |
1023 | if (ret < 0) |
1024 | goto out; |
1025 | |
1026 | cond_resched(); |
1027 | } |
1028 | if (batch.nr_ops) |
1029 | ret = gntdev_copy(&batch); |
1030 | return ret; |
1031 | |
1032 | out: |
1033 | gntdev_put_pages(&batch); |
1034 | return ret; |
1035 | } |
1036 | |
1037 | static long gntdev_ioctl(struct file *flip, |
1038 | unsigned int cmd, unsigned long arg) |
1039 | { |
1040 | struct gntdev_priv *priv = flip->private_data; |
1041 | void __user *ptr = (void __user *)arg; |
1042 | |
1043 | switch (cmd) { |
1044 | case IOCTL_GNTDEV_MAP_GRANT_REF: |
1045 | return gntdev_ioctl_map_grant_ref(priv, ptr); |
1046 | |
1047 | case IOCTL_GNTDEV_UNMAP_GRANT_REF: |
1048 | return gntdev_ioctl_unmap_grant_ref(priv, ptr); |
1049 | |
1050 | case IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR: |
1051 | return gntdev_ioctl_get_offset_for_vaddr(priv, ptr); |
1052 | |
1053 | case IOCTL_GNTDEV_SET_UNMAP_NOTIFY: |
1054 | return gntdev_ioctl_notify(priv, ptr); |
1055 | |
1056 | case IOCTL_GNTDEV_GRANT_COPY: |
1057 | return gntdev_ioctl_grant_copy(priv, ptr); |
1058 | |
1059 | #ifdef CONFIG_XEN_GNTDEV_DMABUF |
1060 | case IOCTL_GNTDEV_DMABUF_EXP_FROM_REFS: |
1061 | return gntdev_ioctl_dmabuf_exp_from_refs(priv, use_ptemod, ptr); |
1062 | |
1063 | case IOCTL_GNTDEV_DMABUF_EXP_WAIT_RELEASED: |
1064 | return gntdev_ioctl_dmabuf_exp_wait_released(priv, ptr); |
1065 | |
1066 | case IOCTL_GNTDEV_DMABUF_IMP_TO_REFS: |
1067 | return gntdev_ioctl_dmabuf_imp_to_refs(priv, ptr); |
1068 | |
1069 | case IOCTL_GNTDEV_DMABUF_IMP_RELEASE: |
1070 | return gntdev_ioctl_dmabuf_imp_release(priv, ptr); |
1071 | #endif |
1072 | |
1073 | default: |
1074 | pr_debug("priv %p, unknown cmd %x\n" , priv, cmd); |
1075 | return -ENOIOCTLCMD; |
1076 | } |
1077 | |
1078 | return 0; |
1079 | } |
1080 | |
1081 | static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) |
1082 | { |
1083 | struct gntdev_priv *priv = flip->private_data; |
1084 | int index = vma->vm_pgoff; |
1085 | int count = vma_pages(vma); |
1086 | struct gntdev_grant_map *map; |
1087 | int i, err = -EINVAL; |
1088 | |
1089 | if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED)) |
1090 | return -EINVAL; |
1091 | |
1092 | pr_debug("map %d+%d at %lx (pgoff %lx)\n" , |
1093 | index, count, vma->vm_start, vma->vm_pgoff); |
1094 | |
1095 | mutex_lock(&priv->lock); |
1096 | map = gntdev_find_map_index(priv, index, count); |
1097 | if (!map) |
1098 | goto unlock_out; |
1099 | if (use_ptemod && map->vma) |
1100 | goto unlock_out; |
1101 | if (use_ptemod && priv->mm != vma->vm_mm) { |
1102 | pr_warn("Huh? Other mm?\n" ); |
1103 | goto unlock_out; |
1104 | } |
1105 | |
1106 | refcount_inc(&map->users); |
1107 | |
1108 | vma->vm_ops = &gntdev_vmops; |
1109 | |
1110 | vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP | VM_MIXEDMAP; |
1111 | |
1112 | if (use_ptemod) |
1113 | vma->vm_flags |= VM_DONTCOPY; |
1114 | |
1115 | vma->vm_private_data = map; |
1116 | |
1117 | if (use_ptemod) |
1118 | map->vma = vma; |
1119 | |
1120 | if (map->flags) { |
1121 | if ((vma->vm_flags & VM_WRITE) && |
1122 | (map->flags & GNTMAP_readonly)) |
1123 | goto out_unlock_put; |
1124 | } else { |
1125 | map->flags = GNTMAP_host_map; |
1126 | if (!(vma->vm_flags & VM_WRITE)) |
1127 | map->flags |= GNTMAP_readonly; |
1128 | } |
1129 | |
1130 | mutex_unlock(&priv->lock); |
1131 | |
1132 | if (use_ptemod) { |
1133 | map->pages_vm_start = vma->vm_start; |
1134 | err = apply_to_page_range(vma->vm_mm, vma->vm_start, |
1135 | vma->vm_end - vma->vm_start, |
1136 | find_grant_ptes, map); |
1137 | if (err) { |
1138 | pr_warn("find_grant_ptes() failure.\n" ); |
1139 | goto out_put_map; |
1140 | } |
1141 | } |
1142 | |
1143 | err = gntdev_map_grant_pages(map); |
1144 | if (err) |
1145 | goto out_put_map; |
1146 | |
1147 | if (!use_ptemod) { |
1148 | for (i = 0; i < count; i++) { |
1149 | err = vm_insert_page(vma, vma->vm_start + i*PAGE_SIZE, |
1150 | map->pages[i]); |
1151 | if (err) |
1152 | goto out_put_map; |
1153 | } |
1154 | } else { |
1155 | #ifdef CONFIG_X86 |
1156 | /* |
1157 | * If the PTEs were not made special by the grant map |
1158 | * hypercall, do so here. |
1159 | * |
1160 | * This is racy since the mapping is already visible |
1161 | * to userspace but userspace should be well-behaved |
1162 | * enough to not touch it until the mmap() call |
1163 | * returns. |
1164 | */ |
1165 | if (!xen_feature(XENFEAT_gnttab_map_avail_bits)) { |
1166 | apply_to_page_range(vma->vm_mm, vma->vm_start, |
1167 | vma->vm_end - vma->vm_start, |
1168 | set_grant_ptes_as_special, NULL); |
1169 | } |
1170 | #endif |
1171 | } |
1172 | |
1173 | return 0; |
1174 | |
1175 | unlock_out: |
1176 | mutex_unlock(&priv->lock); |
1177 | return err; |
1178 | |
1179 | out_unlock_put: |
1180 | mutex_unlock(&priv->lock); |
1181 | out_put_map: |
1182 | if (use_ptemod) { |
1183 | map->vma = NULL; |
1184 | unmap_grant_pages(map, 0, map->count); |
1185 | } |
1186 | gntdev_put_map(priv, map); |
1187 | return err; |
1188 | } |
1189 | |
1190 | static const struct file_operations gntdev_fops = { |
1191 | .owner = THIS_MODULE, |
1192 | .open = gntdev_open, |
1193 | .release = gntdev_release, |
1194 | .mmap = gntdev_mmap, |
1195 | .unlocked_ioctl = gntdev_ioctl |
1196 | }; |
1197 | |
1198 | static struct miscdevice gntdev_miscdev = { |
1199 | .minor = MISC_DYNAMIC_MINOR, |
1200 | .name = "xen/gntdev" , |
1201 | .fops = &gntdev_fops, |
1202 | }; |
1203 | |
1204 | /* ------------------------------------------------------------------ */ |
1205 | |
1206 | static int __init gntdev_init(void) |
1207 | { |
1208 | int err; |
1209 | |
1210 | if (!xen_domain()) |
1211 | return -ENODEV; |
1212 | |
1213 | use_ptemod = !xen_feature(XENFEAT_auto_translated_physmap); |
1214 | |
1215 | err = misc_register(&gntdev_miscdev); |
1216 | if (err != 0) { |
1217 | pr_err("Could not register gntdev device\n" ); |
1218 | return err; |
1219 | } |
1220 | return 0; |
1221 | } |
1222 | |
1223 | static void __exit gntdev_exit(void) |
1224 | { |
1225 | misc_deregister(&gntdev_miscdev); |
1226 | } |
1227 | |
1228 | module_init(gntdev_init); |
1229 | module_exit(gntdev_exit); |
1230 | |
1231 | /* ------------------------------------------------------------------ */ |
1232 | |