Commit | Line | Data |
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ab31523c GH |
1 | /****************************************************************************** |
2 | * gntdev.c | |
3 | * | |
4 | * Device for accessing (in user-space) pages that have been granted by other | |
5 | * domains. | |
6 | * | |
7 | * Copyright (c) 2006-2007, D G Murray. | |
8 | * (c) 2009 Gerd Hoffmann <kraxel@redhat.com> | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License | |
16 | * along with this program; if not, write to the Free Software | |
17 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
18 | */ | |
19 | ||
20 | #undef DEBUG | |
21 | ||
283c0972 JP |
22 | #define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt |
23 | ||
ab31523c GH |
24 | #include <linux/module.h> |
25 | #include <linux/kernel.h> | |
26 | #include <linux/init.h> | |
27 | #include <linux/miscdevice.h> | |
28 | #include <linux/fs.h> | |
29 | #include <linux/mm.h> | |
30 | #include <linux/mman.h> | |
31 | #include <linux/mmu_notifier.h> | |
32 | #include <linux/types.h> | |
33 | #include <linux/uaccess.h> | |
34 | #include <linux/sched.h> | |
35 | #include <linux/spinlock.h> | |
36 | #include <linux/slab.h> | |
aab8f11a | 37 | #include <linux/highmem.h> |
ab31523c GH |
38 | |
39 | #include <xen/xen.h> | |
40 | #include <xen/grant_table.h> | |
ca47ceaa | 41 | #include <xen/balloon.h> |
ab31523c | 42 | #include <xen/gntdev.h> |
bdc612dc | 43 | #include <xen/events.h> |
ab31523c GH |
44 | #include <asm/xen/hypervisor.h> |
45 | #include <asm/xen/hypercall.h> | |
46 | #include <asm/xen/page.h> | |
47 | ||
48 | MODULE_LICENSE("GPL"); | |
49 | MODULE_AUTHOR("Derek G. Murray <Derek.Murray@cl.cam.ac.uk>, " | |
50 | "Gerd Hoffmann <kraxel@redhat.com>"); | |
51 | MODULE_DESCRIPTION("User-space granted page access driver"); | |
52 | ||
ef91082e | 53 | static int limit = 1024*1024; |
ab31523c | 54 | module_param(limit, int, 0644); |
ef91082e DDG |
55 | MODULE_PARM_DESC(limit, "Maximum number of grants that may be mapped by " |
56 | "the gntdev device"); | |
57 | ||
58 | static atomic_t pages_mapped = ATOMIC_INIT(0); | |
ab31523c | 59 | |
aab8f11a | 60 | static int use_ptemod; |
16a1d022 | 61 | #define populate_freeable_maps use_ptemod |
aab8f11a | 62 | |
ab31523c | 63 | struct gntdev_priv { |
16a1d022 | 64 | /* maps with visible offsets in the file descriptor */ |
ab31523c | 65 | struct list_head maps; |
16a1d022 DDG |
66 | /* maps that are not visible; will be freed on munmap. |
67 | * Only populated if populate_freeable_maps == 1 */ | |
68 | struct list_head freeable_maps; | |
69 | /* lock protects maps and freeable_maps */ | |
1401c00e | 70 | struct mutex lock; |
ab31523c GH |
71 | struct mm_struct *mm; |
72 | struct mmu_notifier mn; | |
73 | }; | |
74 | ||
bdc612dc DDG |
75 | struct unmap_notify { |
76 | int flags; | |
77 | /* Address relative to the start of the grant_map */ | |
78 | int addr; | |
79 | int event; | |
80 | }; | |
81 | ||
ab31523c GH |
82 | struct grant_map { |
83 | struct list_head next; | |
ab31523c GH |
84 | struct vm_area_struct *vma; |
85 | int index; | |
86 | int count; | |
87 | int flags; | |
68b025c8 | 88 | atomic_t users; |
bdc612dc | 89 | struct unmap_notify notify; |
ab31523c GH |
90 | struct ioctl_gntdev_grant_ref *grants; |
91 | struct gnttab_map_grant_ref *map_ops; | |
92 | struct gnttab_unmap_grant_ref *unmap_ops; | |
0930bba6 | 93 | struct gnttab_map_grant_ref *kmap_ops; |
853d0289 | 94 | struct gnttab_unmap_grant_ref *kunmap_ops; |
a12b4eb3 | 95 | struct page **pages; |
dab069c6 | 96 | unsigned long pages_vm_start; |
ab31523c GH |
97 | }; |
98 | ||
aab8f11a DDG |
99 | static int unmap_grant_pages(struct grant_map *map, int offset, int pages); |
100 | ||
ab31523c GH |
101 | /* ------------------------------------------------------------------ */ |
102 | ||
103 | static void gntdev_print_maps(struct gntdev_priv *priv, | |
104 | char *text, int text_index) | |
105 | { | |
106 | #ifdef DEBUG | |
107 | struct grant_map *map; | |
108 | ||
ef91082e | 109 | pr_debug("%s: maps list (priv %p)\n", __func__, priv); |
ab31523c GH |
110 | list_for_each_entry(map, &priv->maps, next) |
111 | pr_debug(" index %2d, count %2d %s\n", | |
112 | map->index, map->count, | |
113 | map->index == text_index && text ? text : ""); | |
114 | #endif | |
115 | } | |
116 | ||
a67baeb7 DV |
117 | static void gntdev_free_map(struct grant_map *map) |
118 | { | |
119 | if (map == NULL) | |
120 | return; | |
121 | ||
122 | if (map->pages) | |
ff4b156f | 123 | gnttab_free_pages(map->count, map->pages); |
a67baeb7 DV |
124 | kfree(map->pages); |
125 | kfree(map->grants); | |
126 | kfree(map->map_ops); | |
127 | kfree(map->unmap_ops); | |
128 | kfree(map->kmap_ops); | |
853d0289 | 129 | kfree(map->kunmap_ops); |
a67baeb7 DV |
130 | kfree(map); |
131 | } | |
132 | ||
ab31523c GH |
133 | static struct grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count) |
134 | { | |
135 | struct grant_map *add; | |
a12b4eb3 | 136 | int i; |
ab31523c GH |
137 | |
138 | add = kzalloc(sizeof(struct grant_map), GFP_KERNEL); | |
139 | if (NULL == add) | |
140 | return NULL; | |
141 | ||
fc6e0c3b DC |
142 | add->grants = kcalloc(count, sizeof(add->grants[0]), GFP_KERNEL); |
143 | add->map_ops = kcalloc(count, sizeof(add->map_ops[0]), GFP_KERNEL); | |
144 | add->unmap_ops = kcalloc(count, sizeof(add->unmap_ops[0]), GFP_KERNEL); | |
145 | add->kmap_ops = kcalloc(count, sizeof(add->kmap_ops[0]), GFP_KERNEL); | |
853d0289 | 146 | add->kunmap_ops = kcalloc(count, sizeof(add->kunmap_ops[0]), GFP_KERNEL); |
fc6e0c3b | 147 | add->pages = kcalloc(count, sizeof(add->pages[0]), GFP_KERNEL); |
a12b4eb3 SS |
148 | if (NULL == add->grants || |
149 | NULL == add->map_ops || | |
150 | NULL == add->unmap_ops || | |
0930bba6 | 151 | NULL == add->kmap_ops || |
853d0289 | 152 | NULL == add->kunmap_ops || |
a12b4eb3 | 153 | NULL == add->pages) |
ab31523c GH |
154 | goto err; |
155 | ||
ff4b156f | 156 | if (gnttab_alloc_pages(count, add->pages)) |
ca47ceaa DDG |
157 | goto err; |
158 | ||
a12b4eb3 | 159 | for (i = 0; i < count; i++) { |
77c35acb DDG |
160 | add->map_ops[i].handle = -1; |
161 | add->unmap_ops[i].handle = -1; | |
0930bba6 | 162 | add->kmap_ops[i].handle = -1; |
853d0289 | 163 | add->kunmap_ops[i].handle = -1; |
a12b4eb3 SS |
164 | } |
165 | ||
ab31523c GH |
166 | add->index = 0; |
167 | add->count = count; | |
68b025c8 | 168 | atomic_set(&add->users, 1); |
ab31523c | 169 | |
ab31523c GH |
170 | return add; |
171 | ||
172 | err: | |
a67baeb7 | 173 | gntdev_free_map(add); |
ab31523c GH |
174 | return NULL; |
175 | } | |
176 | ||
177 | static void gntdev_add_map(struct gntdev_priv *priv, struct grant_map *add) | |
178 | { | |
179 | struct grant_map *map; | |
180 | ||
181 | list_for_each_entry(map, &priv->maps, next) { | |
182 | if (add->index + add->count < map->index) { | |
183 | list_add_tail(&add->next, &map->next); | |
184 | goto done; | |
185 | } | |
186 | add->index = map->index + map->count; | |
187 | } | |
188 | list_add_tail(&add->next, &priv->maps); | |
189 | ||
190 | done: | |
ab31523c GH |
191 | gntdev_print_maps(priv, "[new]", add->index); |
192 | } | |
193 | ||
194 | static struct grant_map *gntdev_find_map_index(struct gntdev_priv *priv, | |
195 | int index, int count) | |
196 | { | |
197 | struct grant_map *map; | |
198 | ||
199 | list_for_each_entry(map, &priv->maps, next) { | |
200 | if (map->index != index) | |
201 | continue; | |
bdc612dc | 202 | if (count && map->count != count) |
ab31523c GH |
203 | continue; |
204 | return map; | |
205 | } | |
206 | return NULL; | |
207 | } | |
208 | ||
16a1d022 | 209 | static void gntdev_put_map(struct gntdev_priv *priv, struct grant_map *map) |
ab31523c GH |
210 | { |
211 | if (!map) | |
212 | return; | |
a12b4eb3 | 213 | |
68b025c8 DDG |
214 | if (!atomic_dec_and_test(&map->users)) |
215 | return; | |
216 | ||
217 | atomic_sub(map->count, &pages_mapped); | |
218 | ||
0cc678f8 | 219 | if (map->notify.flags & UNMAP_NOTIFY_SEND_EVENT) { |
bdc612dc | 220 | notify_remote_via_evtchn(map->notify.event); |
0cc678f8 DDG |
221 | evtchn_put(map->notify.event); |
222 | } | |
bdc612dc | 223 | |
16a1d022 | 224 | if (populate_freeable_maps && priv) { |
1401c00e | 225 | mutex_lock(&priv->lock); |
16a1d022 | 226 | list_del(&map->next); |
1401c00e | 227 | mutex_unlock(&priv->lock); |
16a1d022 DDG |
228 | } |
229 | ||
a67baeb7 DV |
230 | if (map->pages && !use_ptemod) |
231 | unmap_grant_pages(map, 0, map->count); | |
232 | gntdev_free_map(map); | |
ab31523c GH |
233 | } |
234 | ||
235 | /* ------------------------------------------------------------------ */ | |
236 | ||
237 | static int find_grant_ptes(pte_t *pte, pgtable_t token, | |
238 | unsigned long addr, void *data) | |
239 | { | |
240 | struct grant_map *map = data; | |
241 | unsigned int pgnr = (addr - map->vma->vm_start) >> PAGE_SHIFT; | |
aab8f11a | 242 | int flags = map->flags | GNTMAP_application_map | GNTMAP_contains_pte; |
ab31523c GH |
243 | u64 pte_maddr; |
244 | ||
245 | BUG_ON(pgnr >= map->count); | |
ba5d1012 JF |
246 | pte_maddr = arbitrary_virt_to_machine(pte).maddr; |
247 | ||
923b2919 DV |
248 | /* |
249 | * Set the PTE as special to force get_user_pages_fast() fall | |
250 | * back to the slow path. If this is not supported as part of | |
251 | * the grant map, it will be done afterwards. | |
252 | */ | |
253 | if (xen_feature(XENFEAT_gnttab_map_avail_bits)) | |
254 | flags |= (1 << _GNTMAP_guest_avail0); | |
255 | ||
aab8f11a | 256 | gnttab_set_map_op(&map->map_ops[pgnr], pte_maddr, flags, |
ab31523c GH |
257 | map->grants[pgnr].ref, |
258 | map->grants[pgnr].domid); | |
aab8f11a | 259 | gnttab_set_unmap_op(&map->unmap_ops[pgnr], pte_maddr, flags, |
77c35acb | 260 | -1 /* handle */); |
ab31523c GH |
261 | return 0; |
262 | } | |
263 | ||
923b2919 DV |
264 | #ifdef CONFIG_X86 |
265 | static int set_grant_ptes_as_special(pte_t *pte, pgtable_t token, | |
266 | unsigned long addr, void *data) | |
267 | { | |
268 | set_pte_at(current->mm, addr, pte, pte_mkspecial(*pte)); | |
269 | return 0; | |
270 | } | |
271 | #endif | |
272 | ||
ab31523c GH |
273 | static int map_grant_pages(struct grant_map *map) |
274 | { | |
275 | int i, err = 0; | |
aab8f11a DDG |
276 | |
277 | if (!use_ptemod) { | |
12996fc3 | 278 | /* Note: it could already be mapped */ |
77c35acb | 279 | if (map->map_ops[0].handle != -1) |
12996fc3 | 280 | return 0; |
aab8f11a | 281 | for (i = 0; i < map->count; i++) { |
38eaeb0f | 282 | unsigned long addr = (unsigned long) |
aab8f11a DDG |
283 | pfn_to_kaddr(page_to_pfn(map->pages[i])); |
284 | gnttab_set_map_op(&map->map_ops[i], addr, map->flags, | |
285 | map->grants[i].ref, | |
286 | map->grants[i].domid); | |
287 | gnttab_set_unmap_op(&map->unmap_ops[i], addr, | |
77c35acb | 288 | map->flags, -1 /* handle */); |
aab8f11a | 289 | } |
0930bba6 SS |
290 | } else { |
291 | /* | |
292 | * Setup the map_ops corresponding to the pte entries pointing | |
293 | * to the kernel linear addresses of the struct pages. | |
294 | * These ptes are completely different from the user ptes dealt | |
295 | * with find_grant_ptes. | |
296 | */ | |
297 | for (i = 0; i < map->count; i++) { | |
0930bba6 SS |
298 | unsigned long address = (unsigned long) |
299 | pfn_to_kaddr(page_to_pfn(map->pages[i])); | |
0930bba6 SS |
300 | BUG_ON(PageHighMem(map->pages[i])); |
301 | ||
ee072640 SS |
302 | gnttab_set_map_op(&map->kmap_ops[i], address, |
303 | map->flags | GNTMAP_host_map, | |
0930bba6 SS |
304 | map->grants[i].ref, |
305 | map->grants[i].domid); | |
853d0289 DV |
306 | gnttab_set_unmap_op(&map->kunmap_ops[i], address, |
307 | map->flags | GNTMAP_host_map, -1); | |
0930bba6 | 308 | } |
aab8f11a | 309 | } |
ab31523c GH |
310 | |
311 | pr_debug("map %d+%d\n", map->index, map->count); | |
e85fc980 KRW |
312 | err = gnttab_map_refs(map->map_ops, use_ptemod ? map->kmap_ops : NULL, |
313 | map->pages, map->count); | |
ab31523c GH |
314 | if (err) |
315 | return err; | |
316 | ||
317 | for (i = 0; i < map->count; i++) { | |
853d0289 | 318 | if (map->map_ops[i].status) { |
ab31523c | 319 | err = -EINVAL; |
853d0289 | 320 | continue; |
77c35acb | 321 | } |
853d0289 DV |
322 | |
323 | map->unmap_ops[i].handle = map->map_ops[i].handle; | |
324 | if (use_ptemod) | |
325 | map->kunmap_ops[i].handle = map->kmap_ops[i].handle; | |
ab31523c GH |
326 | } |
327 | return err; | |
328 | } | |
329 | ||
74528225 JH |
330 | struct unmap_grant_pages_callback_data |
331 | { | |
332 | struct completion completion; | |
333 | int result; | |
334 | }; | |
335 | ||
336 | static void unmap_grant_callback(int result, | |
337 | struct gntab_unmap_queue_data *data) | |
338 | { | |
339 | struct unmap_grant_pages_callback_data* d = data->data; | |
340 | ||
341 | d->result = result; | |
342 | complete(&d->completion); | |
343 | } | |
344 | ||
b57c1869 | 345 | static int __unmap_grant_pages(struct grant_map *map, int offset, int pages) |
ab31523c GH |
346 | { |
347 | int i, err = 0; | |
74528225 JH |
348 | struct gntab_unmap_queue_data unmap_data; |
349 | struct unmap_grant_pages_callback_data data; | |
350 | ||
351 | init_completion(&data.completion); | |
352 | unmap_data.data = &data; | |
353 | unmap_data.done= &unmap_grant_callback; | |
ab31523c | 354 | |
bdc612dc DDG |
355 | if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) { |
356 | int pgno = (map->notify.addr >> PAGE_SHIFT); | |
1affa98d DDG |
357 | if (pgno >= offset && pgno < offset + pages) { |
358 | /* No need for kmap, pages are in lowmem */ | |
359 | uint8_t *tmp = pfn_to_kaddr(page_to_pfn(map->pages[pgno])); | |
bdc612dc | 360 | tmp[map->notify.addr & (PAGE_SIZE-1)] = 0; |
bdc612dc DDG |
361 | map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE; |
362 | } | |
363 | } | |
364 | ||
74528225 JH |
365 | unmap_data.unmap_ops = map->unmap_ops + offset; |
366 | unmap_data.kunmap_ops = use_ptemod ? map->kunmap_ops + offset : NULL; | |
367 | unmap_data.pages = map->pages + offset; | |
368 | unmap_data.count = pages; | |
369 | ||
370 | gnttab_unmap_refs_async(&unmap_data); | |
371 | ||
372 | wait_for_completion(&data.completion); | |
373 | if (data.result) | |
374 | return data.result; | |
ab31523c GH |
375 | |
376 | for (i = 0; i < pages; i++) { | |
377 | if (map->unmap_ops[offset+i].status) | |
378 | err = -EINVAL; | |
77c35acb DDG |
379 | pr_debug("unmap handle=%d st=%d\n", |
380 | map->unmap_ops[offset+i].handle, | |
381 | map->unmap_ops[offset+i].status); | |
382 | map->unmap_ops[offset+i].handle = -1; | |
ab31523c GH |
383 | } |
384 | return err; | |
385 | } | |
386 | ||
b57c1869 DDG |
387 | static int unmap_grant_pages(struct grant_map *map, int offset, int pages) |
388 | { | |
389 | int range, err = 0; | |
390 | ||
391 | pr_debug("unmap %d+%d [%d+%d]\n", map->index, map->count, offset, pages); | |
392 | ||
393 | /* It is possible the requested range will have a "hole" where we | |
394 | * already unmapped some of the grants. Only unmap valid ranges. | |
395 | */ | |
396 | while (pages && !err) { | |
77c35acb | 397 | while (pages && map->unmap_ops[offset].handle == -1) { |
b57c1869 DDG |
398 | offset++; |
399 | pages--; | |
400 | } | |
401 | range = 0; | |
402 | while (range < pages) { | |
77c35acb | 403 | if (map->unmap_ops[offset+range].handle == -1) { |
b57c1869 DDG |
404 | range--; |
405 | break; | |
406 | } | |
407 | range++; | |
408 | } | |
409 | err = __unmap_grant_pages(map, offset, range); | |
410 | offset += range; | |
411 | pages -= range; | |
412 | } | |
413 | ||
414 | return err; | |
415 | } | |
416 | ||
ab31523c GH |
417 | /* ------------------------------------------------------------------ */ |
418 | ||
d79647ae DDG |
419 | static void gntdev_vma_open(struct vm_area_struct *vma) |
420 | { | |
421 | struct grant_map *map = vma->vm_private_data; | |
422 | ||
423 | pr_debug("gntdev_vma_open %p\n", vma); | |
424 | atomic_inc(&map->users); | |
425 | } | |
426 | ||
ab31523c GH |
427 | static void gntdev_vma_close(struct vm_area_struct *vma) |
428 | { | |
429 | struct grant_map *map = vma->vm_private_data; | |
16a1d022 DDG |
430 | struct file *file = vma->vm_file; |
431 | struct gntdev_priv *priv = file->private_data; | |
ab31523c | 432 | |
d79647ae | 433 | pr_debug("gntdev_vma_close %p\n", vma); |
2512f298 | 434 | if (use_ptemod) { |
2512f298 DDG |
435 | /* It is possible that an mmu notifier could be running |
436 | * concurrently, so take priv->lock to ensure that the vma won't | |
437 | * vanishing during the unmap_grant_pages call, since we will | |
438 | * spin here until that completes. Such a concurrent call will | |
439 | * not do any unmapping, since that has been done prior to | |
440 | * closing the vma, but it may still iterate the unmap_ops list. | |
441 | */ | |
1401c00e | 442 | mutex_lock(&priv->lock); |
2512f298 | 443 | map->vma = NULL; |
1401c00e | 444 | mutex_unlock(&priv->lock); |
2512f298 | 445 | } |
ab31523c | 446 | vma->vm_private_data = NULL; |
16a1d022 | 447 | gntdev_put_map(priv, map); |
ab31523c GH |
448 | } |
449 | ||
dab069c6 DV |
450 | static struct page *gntdev_vma_find_special_page(struct vm_area_struct *vma, |
451 | unsigned long addr) | |
452 | { | |
453 | struct grant_map *map = vma->vm_private_data; | |
454 | ||
455 | return map->pages[(addr - map->pages_vm_start) >> PAGE_SHIFT]; | |
456 | } | |
457 | ||
ab31523c | 458 | static struct vm_operations_struct gntdev_vmops = { |
d79647ae | 459 | .open = gntdev_vma_open, |
ab31523c | 460 | .close = gntdev_vma_close, |
dab069c6 | 461 | .find_special_page = gntdev_vma_find_special_page, |
ab31523c GH |
462 | }; |
463 | ||
464 | /* ------------------------------------------------------------------ */ | |
465 | ||
16a1d022 DDG |
466 | static void unmap_if_in_range(struct grant_map *map, |
467 | unsigned long start, unsigned long end) | |
468 | { | |
469 | unsigned long mstart, mend; | |
470 | int err; | |
471 | ||
472 | if (!map->vma) | |
473 | return; | |
474 | if (map->vma->vm_start >= end) | |
475 | return; | |
476 | if (map->vma->vm_end <= start) | |
477 | return; | |
478 | mstart = max(start, map->vma->vm_start); | |
479 | mend = min(end, map->vma->vm_end); | |
480 | pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n", | |
481 | map->index, map->count, | |
482 | map->vma->vm_start, map->vma->vm_end, | |
483 | start, end, mstart, mend); | |
484 | err = unmap_grant_pages(map, | |
485 | (mstart - map->vma->vm_start) >> PAGE_SHIFT, | |
486 | (mend - mstart) >> PAGE_SHIFT); | |
487 | WARN_ON(err); | |
488 | } | |
489 | ||
ab31523c GH |
490 | static void mn_invl_range_start(struct mmu_notifier *mn, |
491 | struct mm_struct *mm, | |
492 | unsigned long start, unsigned long end) | |
493 | { | |
494 | struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn); | |
495 | struct grant_map *map; | |
ab31523c | 496 | |
1401c00e | 497 | mutex_lock(&priv->lock); |
ab31523c | 498 | list_for_each_entry(map, &priv->maps, next) { |
16a1d022 DDG |
499 | unmap_if_in_range(map, start, end); |
500 | } | |
501 | list_for_each_entry(map, &priv->freeable_maps, next) { | |
502 | unmap_if_in_range(map, start, end); | |
ab31523c | 503 | } |
1401c00e | 504 | mutex_unlock(&priv->lock); |
ab31523c GH |
505 | } |
506 | ||
507 | static void mn_invl_page(struct mmu_notifier *mn, | |
508 | struct mm_struct *mm, | |
509 | unsigned long address) | |
510 | { | |
511 | mn_invl_range_start(mn, mm, address, address + PAGE_SIZE); | |
512 | } | |
513 | ||
514 | static void mn_release(struct mmu_notifier *mn, | |
515 | struct mm_struct *mm) | |
516 | { | |
517 | struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn); | |
518 | struct grant_map *map; | |
519 | int err; | |
520 | ||
1401c00e | 521 | mutex_lock(&priv->lock); |
ab31523c GH |
522 | list_for_each_entry(map, &priv->maps, next) { |
523 | if (!map->vma) | |
524 | continue; | |
525 | pr_debug("map %d+%d (%lx %lx)\n", | |
526 | map->index, map->count, | |
527 | map->vma->vm_start, map->vma->vm_end); | |
528 | err = unmap_grant_pages(map, /* offset */ 0, map->count); | |
529 | WARN_ON(err); | |
530 | } | |
16a1d022 DDG |
531 | list_for_each_entry(map, &priv->freeable_maps, next) { |
532 | if (!map->vma) | |
533 | continue; | |
534 | pr_debug("map %d+%d (%lx %lx)\n", | |
535 | map->index, map->count, | |
536 | map->vma->vm_start, map->vma->vm_end); | |
537 | err = unmap_grant_pages(map, /* offset */ 0, map->count); | |
538 | WARN_ON(err); | |
539 | } | |
1401c00e | 540 | mutex_unlock(&priv->lock); |
ab31523c GH |
541 | } |
542 | ||
b8b0f559 | 543 | static struct mmu_notifier_ops gntdev_mmu_ops = { |
ab31523c GH |
544 | .release = mn_release, |
545 | .invalidate_page = mn_invl_page, | |
546 | .invalidate_range_start = mn_invl_range_start, | |
547 | }; | |
548 | ||
549 | /* ------------------------------------------------------------------ */ | |
550 | ||
551 | static int gntdev_open(struct inode *inode, struct file *flip) | |
552 | { | |
553 | struct gntdev_priv *priv; | |
554 | int ret = 0; | |
555 | ||
556 | priv = kzalloc(sizeof(*priv), GFP_KERNEL); | |
557 | if (!priv) | |
558 | return -ENOMEM; | |
559 | ||
560 | INIT_LIST_HEAD(&priv->maps); | |
16a1d022 | 561 | INIT_LIST_HEAD(&priv->freeable_maps); |
1401c00e | 562 | mutex_init(&priv->lock); |
ab31523c | 563 | |
aab8f11a DDG |
564 | if (use_ptemod) { |
565 | priv->mm = get_task_mm(current); | |
566 | if (!priv->mm) { | |
567 | kfree(priv); | |
568 | return -ENOMEM; | |
569 | } | |
570 | priv->mn.ops = &gntdev_mmu_ops; | |
571 | ret = mmu_notifier_register(&priv->mn, priv->mm); | |
572 | mmput(priv->mm); | |
ab31523c | 573 | } |
ab31523c GH |
574 | |
575 | if (ret) { | |
576 | kfree(priv); | |
577 | return ret; | |
578 | } | |
579 | ||
580 | flip->private_data = priv; | |
581 | pr_debug("priv %p\n", priv); | |
582 | ||
583 | return 0; | |
584 | } | |
585 | ||
586 | static int gntdev_release(struct inode *inode, struct file *flip) | |
587 | { | |
588 | struct gntdev_priv *priv = flip->private_data; | |
589 | struct grant_map *map; | |
ab31523c GH |
590 | |
591 | pr_debug("priv %p\n", priv); | |
592 | ||
ab31523c GH |
593 | while (!list_empty(&priv->maps)) { |
594 | map = list_entry(priv->maps.next, struct grant_map, next); | |
68b025c8 | 595 | list_del(&map->next); |
16a1d022 | 596 | gntdev_put_map(NULL /* already removed */, map); |
ab31523c | 597 | } |
16a1d022 | 598 | WARN_ON(!list_empty(&priv->freeable_maps)); |
ab31523c | 599 | |
aab8f11a DDG |
600 | if (use_ptemod) |
601 | mmu_notifier_unregister(&priv->mn, priv->mm); | |
ab31523c GH |
602 | kfree(priv); |
603 | return 0; | |
604 | } | |
605 | ||
606 | static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv, | |
607 | struct ioctl_gntdev_map_grant_ref __user *u) | |
608 | { | |
609 | struct ioctl_gntdev_map_grant_ref op; | |
610 | struct grant_map *map; | |
611 | int err; | |
612 | ||
613 | if (copy_from_user(&op, u, sizeof(op)) != 0) | |
614 | return -EFAULT; | |
615 | pr_debug("priv %p, add %d\n", priv, op.count); | |
616 | if (unlikely(op.count <= 0)) | |
617 | return -EINVAL; | |
ab31523c GH |
618 | |
619 | err = -ENOMEM; | |
620 | map = gntdev_alloc_map(priv, op.count); | |
621 | if (!map) | |
622 | return err; | |
ef91082e | 623 | |
68b025c8 DDG |
624 | if (unlikely(atomic_add_return(op.count, &pages_mapped) > limit)) { |
625 | pr_debug("can't map: over limit\n"); | |
16a1d022 | 626 | gntdev_put_map(NULL, map); |
ab31523c GH |
627 | return err; |
628 | } | |
629 | ||
68b025c8 DDG |
630 | if (copy_from_user(map->grants, &u->refs, |
631 | sizeof(map->grants[0]) * op.count) != 0) { | |
16a1d022 DDG |
632 | gntdev_put_map(NULL, map); |
633 | return -EFAULT; | |
ef91082e DDG |
634 | } |
635 | ||
1401c00e | 636 | mutex_lock(&priv->lock); |
ab31523c GH |
637 | gntdev_add_map(priv, map); |
638 | op.index = map->index << PAGE_SHIFT; | |
1401c00e | 639 | mutex_unlock(&priv->lock); |
ab31523c | 640 | |
68b025c8 DDG |
641 | if (copy_to_user(u, &op, sizeof(op)) != 0) |
642 | return -EFAULT; | |
643 | ||
ab31523c GH |
644 | return 0; |
645 | } | |
646 | ||
647 | static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv *priv, | |
648 | struct ioctl_gntdev_unmap_grant_ref __user *u) | |
649 | { | |
650 | struct ioctl_gntdev_unmap_grant_ref op; | |
651 | struct grant_map *map; | |
652 | int err = -ENOENT; | |
653 | ||
654 | if (copy_from_user(&op, u, sizeof(op)) != 0) | |
655 | return -EFAULT; | |
656 | pr_debug("priv %p, del %d+%d\n", priv, (int)op.index, (int)op.count); | |
657 | ||
1401c00e | 658 | mutex_lock(&priv->lock); |
ab31523c | 659 | map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count); |
68b025c8 DDG |
660 | if (map) { |
661 | list_del(&map->next); | |
16a1d022 DDG |
662 | if (populate_freeable_maps) |
663 | list_add_tail(&map->next, &priv->freeable_maps); | |
68b025c8 DDG |
664 | err = 0; |
665 | } | |
1401c00e | 666 | mutex_unlock(&priv->lock); |
1f1503ba | 667 | if (map) |
16a1d022 | 668 | gntdev_put_map(priv, map); |
ab31523c GH |
669 | return err; |
670 | } | |
671 | ||
672 | static long gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv *priv, | |
673 | struct ioctl_gntdev_get_offset_for_vaddr __user *u) | |
674 | { | |
675 | struct ioctl_gntdev_get_offset_for_vaddr op; | |
a879211b | 676 | struct vm_area_struct *vma; |
ab31523c | 677 | struct grant_map *map; |
2512f298 | 678 | int rv = -EINVAL; |
ab31523c GH |
679 | |
680 | if (copy_from_user(&op, u, sizeof(op)) != 0) | |
681 | return -EFAULT; | |
682 | pr_debug("priv %p, offset for vaddr %lx\n", priv, (unsigned long)op.vaddr); | |
683 | ||
2512f298 | 684 | down_read(¤t->mm->mmap_sem); |
a879211b DDG |
685 | vma = find_vma(current->mm, op.vaddr); |
686 | if (!vma || vma->vm_ops != &gntdev_vmops) | |
2512f298 | 687 | goto out_unlock; |
a879211b DDG |
688 | |
689 | map = vma->vm_private_data; | |
690 | if (!map) | |
2512f298 | 691 | goto out_unlock; |
a879211b | 692 | |
ab31523c GH |
693 | op.offset = map->index << PAGE_SHIFT; |
694 | op.count = map->count; | |
2512f298 | 695 | rv = 0; |
ab31523c | 696 | |
2512f298 DDG |
697 | out_unlock: |
698 | up_read(¤t->mm->mmap_sem); | |
699 | ||
700 | if (rv == 0 && copy_to_user(u, &op, sizeof(op)) != 0) | |
ab31523c | 701 | return -EFAULT; |
2512f298 | 702 | return rv; |
ab31523c GH |
703 | } |
704 | ||
bdc612dc DDG |
705 | static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u) |
706 | { | |
707 | struct ioctl_gntdev_unmap_notify op; | |
708 | struct grant_map *map; | |
709 | int rc; | |
0cc678f8 DDG |
710 | int out_flags; |
711 | unsigned int out_event; | |
bdc612dc DDG |
712 | |
713 | if (copy_from_user(&op, u, sizeof(op))) | |
714 | return -EFAULT; | |
715 | ||
716 | if (op.action & ~(UNMAP_NOTIFY_CLEAR_BYTE|UNMAP_NOTIFY_SEND_EVENT)) | |
717 | return -EINVAL; | |
718 | ||
0cc678f8 DDG |
719 | /* We need to grab a reference to the event channel we are going to use |
720 | * to send the notify before releasing the reference we may already have | |
721 | * (if someone has called this ioctl twice). This is required so that | |
722 | * it is possible to change the clear_byte part of the notification | |
723 | * without disturbing the event channel part, which may now be the last | |
724 | * reference to that event channel. | |
725 | */ | |
726 | if (op.action & UNMAP_NOTIFY_SEND_EVENT) { | |
727 | if (evtchn_get(op.event_channel_port)) | |
728 | return -EINVAL; | |
729 | } | |
730 | ||
731 | out_flags = op.action; | |
732 | out_event = op.event_channel_port; | |
733 | ||
1401c00e | 734 | mutex_lock(&priv->lock); |
bdc612dc DDG |
735 | |
736 | list_for_each_entry(map, &priv->maps, next) { | |
737 | uint64_t begin = map->index << PAGE_SHIFT; | |
738 | uint64_t end = (map->index + map->count) << PAGE_SHIFT; | |
739 | if (op.index >= begin && op.index < end) | |
740 | goto found; | |
741 | } | |
742 | rc = -ENOENT; | |
743 | goto unlock_out; | |
744 | ||
745 | found: | |
9960be97 DDG |
746 | if ((op.action & UNMAP_NOTIFY_CLEAR_BYTE) && |
747 | (map->flags & GNTMAP_readonly)) { | |
748 | rc = -EINVAL; | |
749 | goto unlock_out; | |
750 | } | |
751 | ||
0cc678f8 DDG |
752 | out_flags = map->notify.flags; |
753 | out_event = map->notify.event; | |
754 | ||
bdc612dc DDG |
755 | map->notify.flags = op.action; |
756 | map->notify.addr = op.index - (map->index << PAGE_SHIFT); | |
757 | map->notify.event = op.event_channel_port; | |
0cc678f8 | 758 | |
bdc612dc | 759 | rc = 0; |
0cc678f8 | 760 | |
bdc612dc | 761 | unlock_out: |
1401c00e | 762 | mutex_unlock(&priv->lock); |
0cc678f8 DDG |
763 | |
764 | /* Drop the reference to the event channel we did not save in the map */ | |
765 | if (out_flags & UNMAP_NOTIFY_SEND_EVENT) | |
766 | evtchn_put(out_event); | |
767 | ||
bdc612dc DDG |
768 | return rc; |
769 | } | |
770 | ||
ab31523c GH |
771 | static long gntdev_ioctl(struct file *flip, |
772 | unsigned int cmd, unsigned long arg) | |
773 | { | |
774 | struct gntdev_priv *priv = flip->private_data; | |
775 | void __user *ptr = (void __user *)arg; | |
776 | ||
777 | switch (cmd) { | |
778 | case IOCTL_GNTDEV_MAP_GRANT_REF: | |
779 | return gntdev_ioctl_map_grant_ref(priv, ptr); | |
780 | ||
781 | case IOCTL_GNTDEV_UNMAP_GRANT_REF: | |
782 | return gntdev_ioctl_unmap_grant_ref(priv, ptr); | |
783 | ||
784 | case IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR: | |
785 | return gntdev_ioctl_get_offset_for_vaddr(priv, ptr); | |
786 | ||
bdc612dc DDG |
787 | case IOCTL_GNTDEV_SET_UNMAP_NOTIFY: |
788 | return gntdev_ioctl_notify(priv, ptr); | |
789 | ||
ab31523c GH |
790 | default: |
791 | pr_debug("priv %p, unknown cmd %x\n", priv, cmd); | |
792 | return -ENOIOCTLCMD; | |
793 | } | |
794 | ||
795 | return 0; | |
796 | } | |
797 | ||
798 | static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) | |
799 | { | |
800 | struct gntdev_priv *priv = flip->private_data; | |
801 | int index = vma->vm_pgoff; | |
802 | int count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; | |
803 | struct grant_map *map; | |
aab8f11a | 804 | int i, err = -EINVAL; |
ab31523c GH |
805 | |
806 | if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED)) | |
807 | return -EINVAL; | |
808 | ||
809 | pr_debug("map %d+%d at %lx (pgoff %lx)\n", | |
810 | index, count, vma->vm_start, vma->vm_pgoff); | |
811 | ||
1401c00e | 812 | mutex_lock(&priv->lock); |
ab31523c GH |
813 | map = gntdev_find_map_index(priv, index, count); |
814 | if (!map) | |
815 | goto unlock_out; | |
aab8f11a | 816 | if (use_ptemod && map->vma) |
ab31523c | 817 | goto unlock_out; |
aab8f11a | 818 | if (use_ptemod && priv->mm != vma->vm_mm) { |
283c0972 | 819 | pr_warn("Huh? Other mm?\n"); |
ab31523c GH |
820 | goto unlock_out; |
821 | } | |
822 | ||
68b025c8 DDG |
823 | atomic_inc(&map->users); |
824 | ||
ab31523c GH |
825 | vma->vm_ops = &gntdev_vmops; |
826 | ||
314e51b9 | 827 | vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP; |
d79647ae DDG |
828 | |
829 | if (use_ptemod) | |
e8e937be | 830 | vma->vm_flags |= VM_DONTCOPY; |
ab31523c GH |
831 | |
832 | vma->vm_private_data = map; | |
ab31523c | 833 | |
aab8f11a DDG |
834 | if (use_ptemod) |
835 | map->vma = vma; | |
836 | ||
12996fc3 DDG |
837 | if (map->flags) { |
838 | if ((vma->vm_flags & VM_WRITE) && | |
839 | (map->flags & GNTMAP_readonly)) | |
a93e20a8 | 840 | goto out_unlock_put; |
12996fc3 DDG |
841 | } else { |
842 | map->flags = GNTMAP_host_map; | |
843 | if (!(vma->vm_flags & VM_WRITE)) | |
844 | map->flags |= GNTMAP_readonly; | |
845 | } | |
ab31523c | 846 | |
1401c00e | 847 | mutex_unlock(&priv->lock); |
f0a70c88 | 848 | |
aab8f11a DDG |
849 | if (use_ptemod) { |
850 | err = apply_to_page_range(vma->vm_mm, vma->vm_start, | |
851 | vma->vm_end - vma->vm_start, | |
852 | find_grant_ptes, map); | |
853 | if (err) { | |
283c0972 | 854 | pr_warn("find_grant_ptes() failure.\n"); |
90b6f305 | 855 | goto out_put_map; |
aab8f11a | 856 | } |
ab31523c GH |
857 | } |
858 | ||
859 | err = map_grant_pages(map); | |
90b6f305 DDG |
860 | if (err) |
861 | goto out_put_map; | |
f0a70c88 | 862 | |
aab8f11a DDG |
863 | if (!use_ptemod) { |
864 | for (i = 0; i < count; i++) { | |
865 | err = vm_insert_page(vma, vma->vm_start + i*PAGE_SIZE, | |
866 | map->pages[i]); | |
867 | if (err) | |
90b6f305 | 868 | goto out_put_map; |
aab8f11a | 869 | } |
923b2919 DV |
870 | } else { |
871 | #ifdef CONFIG_X86 | |
872 | /* | |
873 | * If the PTEs were not made special by the grant map | |
874 | * hypercall, do so here. | |
875 | * | |
876 | * This is racy since the mapping is already visible | |
877 | * to userspace but userspace should be well-behaved | |
878 | * enough to not touch it until the mmap() call | |
879 | * returns. | |
880 | */ | |
881 | if (!xen_feature(XENFEAT_gnttab_map_avail_bits)) { | |
882 | apply_to_page_range(vma->vm_mm, vma->vm_start, | |
883 | vma->vm_end - vma->vm_start, | |
884 | set_grant_ptes_as_special, NULL); | |
885 | } | |
886 | #endif | |
dab069c6 | 887 | map->pages_vm_start = vma->vm_start; |
aab8f11a DDG |
888 | } |
889 | ||
f0a70c88 DDG |
890 | return 0; |
891 | ||
ab31523c | 892 | unlock_out: |
1401c00e | 893 | mutex_unlock(&priv->lock); |
ab31523c | 894 | return err; |
90b6f305 | 895 | |
a93e20a8 | 896 | out_unlock_put: |
1401c00e | 897 | mutex_unlock(&priv->lock); |
90b6f305 | 898 | out_put_map: |
84e4075d DDG |
899 | if (use_ptemod) |
900 | map->vma = NULL; | |
16a1d022 | 901 | gntdev_put_map(priv, map); |
90b6f305 | 902 | return err; |
ab31523c GH |
903 | } |
904 | ||
905 | static const struct file_operations gntdev_fops = { | |
906 | .owner = THIS_MODULE, | |
907 | .open = gntdev_open, | |
908 | .release = gntdev_release, | |
909 | .mmap = gntdev_mmap, | |
910 | .unlocked_ioctl = gntdev_ioctl | |
911 | }; | |
912 | ||
913 | static struct miscdevice gntdev_miscdev = { | |
914 | .minor = MISC_DYNAMIC_MINOR, | |
915 | .name = "xen/gntdev", | |
916 | .fops = &gntdev_fops, | |
917 | }; | |
918 | ||
919 | /* ------------------------------------------------------------------ */ | |
920 | ||
921 | static int __init gntdev_init(void) | |
922 | { | |
923 | int err; | |
924 | ||
925 | if (!xen_domain()) | |
926 | return -ENODEV; | |
927 | ||
6926f6d6 | 928 | use_ptemod = !xen_feature(XENFEAT_auto_translated_physmap); |
aab8f11a | 929 | |
ab31523c GH |
930 | err = misc_register(&gntdev_miscdev); |
931 | if (err != 0) { | |
283c0972 | 932 | pr_err("Could not register gntdev device\n"); |
ab31523c GH |
933 | return err; |
934 | } | |
935 | return 0; | |
936 | } | |
937 | ||
938 | static void __exit gntdev_exit(void) | |
939 | { | |
940 | misc_deregister(&gntdev_miscdev); | |
941 | } | |
942 | ||
943 | module_init(gntdev_init); | |
944 | module_exit(gntdev_exit); | |
945 | ||
946 | /* ------------------------------------------------------------------ */ |