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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> |
a9fd60e2 | 44 | #include <xen/page.h> |
ab31523c GH |
45 | #include <asm/xen/hypervisor.h> |
46 | #include <asm/xen/hypercall.h> | |
ab31523c GH |
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 | ||
b57c1869 | 330 | static int __unmap_grant_pages(struct grant_map *map, int offset, int pages) |
ab31523c GH |
331 | { |
332 | int i, err = 0; | |
74528225 | 333 | struct gntab_unmap_queue_data unmap_data; |
ab31523c | 334 | |
bdc612dc DDG |
335 | if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) { |
336 | int pgno = (map->notify.addr >> PAGE_SHIFT); | |
1affa98d DDG |
337 | if (pgno >= offset && pgno < offset + pages) { |
338 | /* No need for kmap, pages are in lowmem */ | |
339 | uint8_t *tmp = pfn_to_kaddr(page_to_pfn(map->pages[pgno])); | |
bdc612dc | 340 | tmp[map->notify.addr & (PAGE_SIZE-1)] = 0; |
bdc612dc DDG |
341 | map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE; |
342 | } | |
343 | } | |
344 | ||
74528225 JH |
345 | unmap_data.unmap_ops = map->unmap_ops + offset; |
346 | unmap_data.kunmap_ops = use_ptemod ? map->kunmap_ops + offset : NULL; | |
347 | unmap_data.pages = map->pages + offset; | |
348 | unmap_data.count = pages; | |
349 | ||
b44166cd BL |
350 | err = gnttab_unmap_refs_sync(&unmap_data); |
351 | if (err) | |
352 | return err; | |
ab31523c GH |
353 | |
354 | for (i = 0; i < pages; i++) { | |
355 | if (map->unmap_ops[offset+i].status) | |
356 | err = -EINVAL; | |
77c35acb DDG |
357 | pr_debug("unmap handle=%d st=%d\n", |
358 | map->unmap_ops[offset+i].handle, | |
359 | map->unmap_ops[offset+i].status); | |
360 | map->unmap_ops[offset+i].handle = -1; | |
ab31523c GH |
361 | } |
362 | return err; | |
363 | } | |
364 | ||
b57c1869 DDG |
365 | static int unmap_grant_pages(struct grant_map *map, int offset, int pages) |
366 | { | |
367 | int range, err = 0; | |
368 | ||
369 | pr_debug("unmap %d+%d [%d+%d]\n", map->index, map->count, offset, pages); | |
370 | ||
371 | /* It is possible the requested range will have a "hole" where we | |
372 | * already unmapped some of the grants. Only unmap valid ranges. | |
373 | */ | |
374 | while (pages && !err) { | |
77c35acb | 375 | while (pages && map->unmap_ops[offset].handle == -1) { |
b57c1869 DDG |
376 | offset++; |
377 | pages--; | |
378 | } | |
379 | range = 0; | |
380 | while (range < pages) { | |
77c35acb | 381 | if (map->unmap_ops[offset+range].handle == -1) { |
b57c1869 DDG |
382 | range--; |
383 | break; | |
384 | } | |
385 | range++; | |
386 | } | |
387 | err = __unmap_grant_pages(map, offset, range); | |
388 | offset += range; | |
389 | pages -= range; | |
390 | } | |
391 | ||
392 | return err; | |
393 | } | |
394 | ||
ab31523c GH |
395 | /* ------------------------------------------------------------------ */ |
396 | ||
d79647ae DDG |
397 | static void gntdev_vma_open(struct vm_area_struct *vma) |
398 | { | |
399 | struct grant_map *map = vma->vm_private_data; | |
400 | ||
401 | pr_debug("gntdev_vma_open %p\n", vma); | |
402 | atomic_inc(&map->users); | |
403 | } | |
404 | ||
ab31523c GH |
405 | static void gntdev_vma_close(struct vm_area_struct *vma) |
406 | { | |
407 | struct grant_map *map = vma->vm_private_data; | |
16a1d022 DDG |
408 | struct file *file = vma->vm_file; |
409 | struct gntdev_priv *priv = file->private_data; | |
ab31523c | 410 | |
d79647ae | 411 | pr_debug("gntdev_vma_close %p\n", vma); |
2512f298 | 412 | if (use_ptemod) { |
2512f298 DDG |
413 | /* It is possible that an mmu notifier could be running |
414 | * concurrently, so take priv->lock to ensure that the vma won't | |
415 | * vanishing during the unmap_grant_pages call, since we will | |
416 | * spin here until that completes. Such a concurrent call will | |
417 | * not do any unmapping, since that has been done prior to | |
418 | * closing the vma, but it may still iterate the unmap_ops list. | |
419 | */ | |
1401c00e | 420 | mutex_lock(&priv->lock); |
2512f298 | 421 | map->vma = NULL; |
1401c00e | 422 | mutex_unlock(&priv->lock); |
2512f298 | 423 | } |
ab31523c | 424 | vma->vm_private_data = NULL; |
16a1d022 | 425 | gntdev_put_map(priv, map); |
ab31523c GH |
426 | } |
427 | ||
dab069c6 DV |
428 | static struct page *gntdev_vma_find_special_page(struct vm_area_struct *vma, |
429 | unsigned long addr) | |
430 | { | |
431 | struct grant_map *map = vma->vm_private_data; | |
432 | ||
433 | return map->pages[(addr - map->pages_vm_start) >> PAGE_SHIFT]; | |
434 | } | |
435 | ||
ab31523c | 436 | static struct vm_operations_struct gntdev_vmops = { |
d79647ae | 437 | .open = gntdev_vma_open, |
ab31523c | 438 | .close = gntdev_vma_close, |
dab069c6 | 439 | .find_special_page = gntdev_vma_find_special_page, |
ab31523c GH |
440 | }; |
441 | ||
442 | /* ------------------------------------------------------------------ */ | |
443 | ||
16a1d022 DDG |
444 | static void unmap_if_in_range(struct grant_map *map, |
445 | unsigned long start, unsigned long end) | |
446 | { | |
447 | unsigned long mstart, mend; | |
448 | int err; | |
449 | ||
450 | if (!map->vma) | |
451 | return; | |
452 | if (map->vma->vm_start >= end) | |
453 | return; | |
454 | if (map->vma->vm_end <= start) | |
455 | return; | |
456 | mstart = max(start, map->vma->vm_start); | |
457 | mend = min(end, map->vma->vm_end); | |
458 | pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n", | |
459 | map->index, map->count, | |
460 | map->vma->vm_start, map->vma->vm_end, | |
461 | start, end, mstart, mend); | |
462 | err = unmap_grant_pages(map, | |
463 | (mstart - map->vma->vm_start) >> PAGE_SHIFT, | |
464 | (mend - mstart) >> PAGE_SHIFT); | |
465 | WARN_ON(err); | |
466 | } | |
467 | ||
ab31523c GH |
468 | static void mn_invl_range_start(struct mmu_notifier *mn, |
469 | struct mm_struct *mm, | |
470 | unsigned long start, unsigned long end) | |
471 | { | |
472 | struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn); | |
473 | struct grant_map *map; | |
ab31523c | 474 | |
1401c00e | 475 | mutex_lock(&priv->lock); |
ab31523c | 476 | list_for_each_entry(map, &priv->maps, next) { |
16a1d022 DDG |
477 | unmap_if_in_range(map, start, end); |
478 | } | |
479 | list_for_each_entry(map, &priv->freeable_maps, next) { | |
480 | unmap_if_in_range(map, start, end); | |
ab31523c | 481 | } |
1401c00e | 482 | mutex_unlock(&priv->lock); |
ab31523c GH |
483 | } |
484 | ||
485 | static void mn_invl_page(struct mmu_notifier *mn, | |
486 | struct mm_struct *mm, | |
487 | unsigned long address) | |
488 | { | |
489 | mn_invl_range_start(mn, mm, address, address + PAGE_SIZE); | |
490 | } | |
491 | ||
492 | static void mn_release(struct mmu_notifier *mn, | |
493 | struct mm_struct *mm) | |
494 | { | |
495 | struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn); | |
496 | struct grant_map *map; | |
497 | int err; | |
498 | ||
1401c00e | 499 | mutex_lock(&priv->lock); |
ab31523c GH |
500 | list_for_each_entry(map, &priv->maps, next) { |
501 | if (!map->vma) | |
502 | continue; | |
503 | pr_debug("map %d+%d (%lx %lx)\n", | |
504 | map->index, map->count, | |
505 | map->vma->vm_start, map->vma->vm_end); | |
506 | err = unmap_grant_pages(map, /* offset */ 0, map->count); | |
507 | WARN_ON(err); | |
508 | } | |
16a1d022 DDG |
509 | list_for_each_entry(map, &priv->freeable_maps, next) { |
510 | if (!map->vma) | |
511 | continue; | |
512 | pr_debug("map %d+%d (%lx %lx)\n", | |
513 | map->index, map->count, | |
514 | map->vma->vm_start, map->vma->vm_end); | |
515 | err = unmap_grant_pages(map, /* offset */ 0, map->count); | |
516 | WARN_ON(err); | |
517 | } | |
1401c00e | 518 | mutex_unlock(&priv->lock); |
ab31523c GH |
519 | } |
520 | ||
b8b0f559 | 521 | static struct mmu_notifier_ops gntdev_mmu_ops = { |
ab31523c GH |
522 | .release = mn_release, |
523 | .invalidate_page = mn_invl_page, | |
524 | .invalidate_range_start = mn_invl_range_start, | |
525 | }; | |
526 | ||
527 | /* ------------------------------------------------------------------ */ | |
528 | ||
529 | static int gntdev_open(struct inode *inode, struct file *flip) | |
530 | { | |
531 | struct gntdev_priv *priv; | |
532 | int ret = 0; | |
533 | ||
534 | priv = kzalloc(sizeof(*priv), GFP_KERNEL); | |
535 | if (!priv) | |
536 | return -ENOMEM; | |
537 | ||
538 | INIT_LIST_HEAD(&priv->maps); | |
16a1d022 | 539 | INIT_LIST_HEAD(&priv->freeable_maps); |
1401c00e | 540 | mutex_init(&priv->lock); |
ab31523c | 541 | |
aab8f11a DDG |
542 | if (use_ptemod) { |
543 | priv->mm = get_task_mm(current); | |
544 | if (!priv->mm) { | |
545 | kfree(priv); | |
546 | return -ENOMEM; | |
547 | } | |
548 | priv->mn.ops = &gntdev_mmu_ops; | |
549 | ret = mmu_notifier_register(&priv->mn, priv->mm); | |
550 | mmput(priv->mm); | |
ab31523c | 551 | } |
ab31523c GH |
552 | |
553 | if (ret) { | |
554 | kfree(priv); | |
555 | return ret; | |
556 | } | |
557 | ||
558 | flip->private_data = priv; | |
559 | pr_debug("priv %p\n", priv); | |
560 | ||
561 | return 0; | |
562 | } | |
563 | ||
564 | static int gntdev_release(struct inode *inode, struct file *flip) | |
565 | { | |
566 | struct gntdev_priv *priv = flip->private_data; | |
567 | struct grant_map *map; | |
ab31523c GH |
568 | |
569 | pr_debug("priv %p\n", priv); | |
570 | ||
30b03d05 | 571 | mutex_lock(&priv->lock); |
ab31523c GH |
572 | while (!list_empty(&priv->maps)) { |
573 | map = list_entry(priv->maps.next, struct grant_map, next); | |
68b025c8 | 574 | list_del(&map->next); |
16a1d022 | 575 | gntdev_put_map(NULL /* already removed */, map); |
ab31523c | 576 | } |
16a1d022 | 577 | WARN_ON(!list_empty(&priv->freeable_maps)); |
30b03d05 | 578 | mutex_unlock(&priv->lock); |
ab31523c | 579 | |
aab8f11a DDG |
580 | if (use_ptemod) |
581 | mmu_notifier_unregister(&priv->mn, priv->mm); | |
ab31523c GH |
582 | kfree(priv); |
583 | return 0; | |
584 | } | |
585 | ||
586 | static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv, | |
587 | struct ioctl_gntdev_map_grant_ref __user *u) | |
588 | { | |
589 | struct ioctl_gntdev_map_grant_ref op; | |
590 | struct grant_map *map; | |
591 | int err; | |
592 | ||
593 | if (copy_from_user(&op, u, sizeof(op)) != 0) | |
594 | return -EFAULT; | |
595 | pr_debug("priv %p, add %d\n", priv, op.count); | |
596 | if (unlikely(op.count <= 0)) | |
597 | return -EINVAL; | |
ab31523c GH |
598 | |
599 | err = -ENOMEM; | |
600 | map = gntdev_alloc_map(priv, op.count); | |
601 | if (!map) | |
602 | return err; | |
ef91082e | 603 | |
68b025c8 DDG |
604 | if (unlikely(atomic_add_return(op.count, &pages_mapped) > limit)) { |
605 | pr_debug("can't map: over limit\n"); | |
16a1d022 | 606 | gntdev_put_map(NULL, map); |
ab31523c GH |
607 | return err; |
608 | } | |
609 | ||
68b025c8 DDG |
610 | if (copy_from_user(map->grants, &u->refs, |
611 | sizeof(map->grants[0]) * op.count) != 0) { | |
16a1d022 DDG |
612 | gntdev_put_map(NULL, map); |
613 | return -EFAULT; | |
ef91082e DDG |
614 | } |
615 | ||
1401c00e | 616 | mutex_lock(&priv->lock); |
ab31523c GH |
617 | gntdev_add_map(priv, map); |
618 | op.index = map->index << PAGE_SHIFT; | |
1401c00e | 619 | mutex_unlock(&priv->lock); |
ab31523c | 620 | |
68b025c8 DDG |
621 | if (copy_to_user(u, &op, sizeof(op)) != 0) |
622 | return -EFAULT; | |
623 | ||
ab31523c GH |
624 | return 0; |
625 | } | |
626 | ||
627 | static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv *priv, | |
628 | struct ioctl_gntdev_unmap_grant_ref __user *u) | |
629 | { | |
630 | struct ioctl_gntdev_unmap_grant_ref op; | |
631 | struct grant_map *map; | |
632 | int err = -ENOENT; | |
633 | ||
634 | if (copy_from_user(&op, u, sizeof(op)) != 0) | |
635 | return -EFAULT; | |
636 | pr_debug("priv %p, del %d+%d\n", priv, (int)op.index, (int)op.count); | |
637 | ||
1401c00e | 638 | mutex_lock(&priv->lock); |
ab31523c | 639 | map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count); |
68b025c8 DDG |
640 | if (map) { |
641 | list_del(&map->next); | |
16a1d022 DDG |
642 | if (populate_freeable_maps) |
643 | list_add_tail(&map->next, &priv->freeable_maps); | |
68b025c8 DDG |
644 | err = 0; |
645 | } | |
1401c00e | 646 | mutex_unlock(&priv->lock); |
1f1503ba | 647 | if (map) |
16a1d022 | 648 | gntdev_put_map(priv, map); |
ab31523c GH |
649 | return err; |
650 | } | |
651 | ||
652 | static long gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv *priv, | |
653 | struct ioctl_gntdev_get_offset_for_vaddr __user *u) | |
654 | { | |
655 | struct ioctl_gntdev_get_offset_for_vaddr op; | |
a879211b | 656 | struct vm_area_struct *vma; |
ab31523c | 657 | struct grant_map *map; |
2512f298 | 658 | int rv = -EINVAL; |
ab31523c GH |
659 | |
660 | if (copy_from_user(&op, u, sizeof(op)) != 0) | |
661 | return -EFAULT; | |
662 | pr_debug("priv %p, offset for vaddr %lx\n", priv, (unsigned long)op.vaddr); | |
663 | ||
2512f298 | 664 | down_read(¤t->mm->mmap_sem); |
a879211b DDG |
665 | vma = find_vma(current->mm, op.vaddr); |
666 | if (!vma || vma->vm_ops != &gntdev_vmops) | |
2512f298 | 667 | goto out_unlock; |
a879211b DDG |
668 | |
669 | map = vma->vm_private_data; | |
670 | if (!map) | |
2512f298 | 671 | goto out_unlock; |
a879211b | 672 | |
ab31523c GH |
673 | op.offset = map->index << PAGE_SHIFT; |
674 | op.count = map->count; | |
2512f298 | 675 | rv = 0; |
ab31523c | 676 | |
2512f298 DDG |
677 | out_unlock: |
678 | up_read(¤t->mm->mmap_sem); | |
679 | ||
680 | if (rv == 0 && copy_to_user(u, &op, sizeof(op)) != 0) | |
ab31523c | 681 | return -EFAULT; |
2512f298 | 682 | return rv; |
ab31523c GH |
683 | } |
684 | ||
bdc612dc DDG |
685 | static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u) |
686 | { | |
687 | struct ioctl_gntdev_unmap_notify op; | |
688 | struct grant_map *map; | |
689 | int rc; | |
0cc678f8 DDG |
690 | int out_flags; |
691 | unsigned int out_event; | |
bdc612dc DDG |
692 | |
693 | if (copy_from_user(&op, u, sizeof(op))) | |
694 | return -EFAULT; | |
695 | ||
696 | if (op.action & ~(UNMAP_NOTIFY_CLEAR_BYTE|UNMAP_NOTIFY_SEND_EVENT)) | |
697 | return -EINVAL; | |
698 | ||
0cc678f8 DDG |
699 | /* We need to grab a reference to the event channel we are going to use |
700 | * to send the notify before releasing the reference we may already have | |
701 | * (if someone has called this ioctl twice). This is required so that | |
702 | * it is possible to change the clear_byte part of the notification | |
703 | * without disturbing the event channel part, which may now be the last | |
704 | * reference to that event channel. | |
705 | */ | |
706 | if (op.action & UNMAP_NOTIFY_SEND_EVENT) { | |
707 | if (evtchn_get(op.event_channel_port)) | |
708 | return -EINVAL; | |
709 | } | |
710 | ||
711 | out_flags = op.action; | |
712 | out_event = op.event_channel_port; | |
713 | ||
1401c00e | 714 | mutex_lock(&priv->lock); |
bdc612dc DDG |
715 | |
716 | list_for_each_entry(map, &priv->maps, next) { | |
717 | uint64_t begin = map->index << PAGE_SHIFT; | |
718 | uint64_t end = (map->index + map->count) << PAGE_SHIFT; | |
719 | if (op.index >= begin && op.index < end) | |
720 | goto found; | |
721 | } | |
722 | rc = -ENOENT; | |
723 | goto unlock_out; | |
724 | ||
725 | found: | |
9960be97 DDG |
726 | if ((op.action & UNMAP_NOTIFY_CLEAR_BYTE) && |
727 | (map->flags & GNTMAP_readonly)) { | |
728 | rc = -EINVAL; | |
729 | goto unlock_out; | |
730 | } | |
731 | ||
0cc678f8 DDG |
732 | out_flags = map->notify.flags; |
733 | out_event = map->notify.event; | |
734 | ||
bdc612dc DDG |
735 | map->notify.flags = op.action; |
736 | map->notify.addr = op.index - (map->index << PAGE_SHIFT); | |
737 | map->notify.event = op.event_channel_port; | |
0cc678f8 | 738 | |
bdc612dc | 739 | rc = 0; |
0cc678f8 | 740 | |
bdc612dc | 741 | unlock_out: |
1401c00e | 742 | mutex_unlock(&priv->lock); |
0cc678f8 DDG |
743 | |
744 | /* Drop the reference to the event channel we did not save in the map */ | |
745 | if (out_flags & UNMAP_NOTIFY_SEND_EVENT) | |
746 | evtchn_put(out_event); | |
747 | ||
bdc612dc DDG |
748 | return rc; |
749 | } | |
750 | ||
ab31523c GH |
751 | static long gntdev_ioctl(struct file *flip, |
752 | unsigned int cmd, unsigned long arg) | |
753 | { | |
754 | struct gntdev_priv *priv = flip->private_data; | |
755 | void __user *ptr = (void __user *)arg; | |
756 | ||
757 | switch (cmd) { | |
758 | case IOCTL_GNTDEV_MAP_GRANT_REF: | |
759 | return gntdev_ioctl_map_grant_ref(priv, ptr); | |
760 | ||
761 | case IOCTL_GNTDEV_UNMAP_GRANT_REF: | |
762 | return gntdev_ioctl_unmap_grant_ref(priv, ptr); | |
763 | ||
764 | case IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR: | |
765 | return gntdev_ioctl_get_offset_for_vaddr(priv, ptr); | |
766 | ||
bdc612dc DDG |
767 | case IOCTL_GNTDEV_SET_UNMAP_NOTIFY: |
768 | return gntdev_ioctl_notify(priv, ptr); | |
769 | ||
ab31523c GH |
770 | default: |
771 | pr_debug("priv %p, unknown cmd %x\n", priv, cmd); | |
772 | return -ENOIOCTLCMD; | |
773 | } | |
774 | ||
775 | return 0; | |
776 | } | |
777 | ||
778 | static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) | |
779 | { | |
780 | struct gntdev_priv *priv = flip->private_data; | |
781 | int index = vma->vm_pgoff; | |
782 | int count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; | |
783 | struct grant_map *map; | |
aab8f11a | 784 | int i, err = -EINVAL; |
ab31523c GH |
785 | |
786 | if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED)) | |
787 | return -EINVAL; | |
788 | ||
789 | pr_debug("map %d+%d at %lx (pgoff %lx)\n", | |
790 | index, count, vma->vm_start, vma->vm_pgoff); | |
791 | ||
1401c00e | 792 | mutex_lock(&priv->lock); |
ab31523c GH |
793 | map = gntdev_find_map_index(priv, index, count); |
794 | if (!map) | |
795 | goto unlock_out; | |
aab8f11a | 796 | if (use_ptemod && map->vma) |
ab31523c | 797 | goto unlock_out; |
aab8f11a | 798 | if (use_ptemod && priv->mm != vma->vm_mm) { |
283c0972 | 799 | pr_warn("Huh? Other mm?\n"); |
ab31523c GH |
800 | goto unlock_out; |
801 | } | |
802 | ||
68b025c8 DDG |
803 | atomic_inc(&map->users); |
804 | ||
ab31523c GH |
805 | vma->vm_ops = &gntdev_vmops; |
806 | ||
314e51b9 | 807 | vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP; |
d79647ae DDG |
808 | |
809 | if (use_ptemod) | |
e8e937be | 810 | vma->vm_flags |= VM_DONTCOPY; |
ab31523c GH |
811 | |
812 | vma->vm_private_data = map; | |
ab31523c | 813 | |
aab8f11a DDG |
814 | if (use_ptemod) |
815 | map->vma = vma; | |
816 | ||
12996fc3 DDG |
817 | if (map->flags) { |
818 | if ((vma->vm_flags & VM_WRITE) && | |
819 | (map->flags & GNTMAP_readonly)) | |
a93e20a8 | 820 | goto out_unlock_put; |
12996fc3 DDG |
821 | } else { |
822 | map->flags = GNTMAP_host_map; | |
823 | if (!(vma->vm_flags & VM_WRITE)) | |
824 | map->flags |= GNTMAP_readonly; | |
825 | } | |
ab31523c | 826 | |
1401c00e | 827 | mutex_unlock(&priv->lock); |
f0a70c88 | 828 | |
aab8f11a DDG |
829 | if (use_ptemod) { |
830 | err = apply_to_page_range(vma->vm_mm, vma->vm_start, | |
831 | vma->vm_end - vma->vm_start, | |
832 | find_grant_ptes, map); | |
833 | if (err) { | |
283c0972 | 834 | pr_warn("find_grant_ptes() failure.\n"); |
90b6f305 | 835 | goto out_put_map; |
aab8f11a | 836 | } |
ab31523c GH |
837 | } |
838 | ||
839 | err = map_grant_pages(map); | |
90b6f305 DDG |
840 | if (err) |
841 | goto out_put_map; | |
f0a70c88 | 842 | |
aab8f11a DDG |
843 | if (!use_ptemod) { |
844 | for (i = 0; i < count; i++) { | |
845 | err = vm_insert_page(vma, vma->vm_start + i*PAGE_SIZE, | |
846 | map->pages[i]); | |
847 | if (err) | |
90b6f305 | 848 | goto out_put_map; |
aab8f11a | 849 | } |
923b2919 DV |
850 | } else { |
851 | #ifdef CONFIG_X86 | |
852 | /* | |
853 | * If the PTEs were not made special by the grant map | |
854 | * hypercall, do so here. | |
855 | * | |
856 | * This is racy since the mapping is already visible | |
857 | * to userspace but userspace should be well-behaved | |
858 | * enough to not touch it until the mmap() call | |
859 | * returns. | |
860 | */ | |
861 | if (!xen_feature(XENFEAT_gnttab_map_avail_bits)) { | |
862 | apply_to_page_range(vma->vm_mm, vma->vm_start, | |
863 | vma->vm_end - vma->vm_start, | |
864 | set_grant_ptes_as_special, NULL); | |
865 | } | |
866 | #endif | |
dab069c6 | 867 | map->pages_vm_start = vma->vm_start; |
aab8f11a DDG |
868 | } |
869 | ||
f0a70c88 DDG |
870 | return 0; |
871 | ||
ab31523c | 872 | unlock_out: |
1401c00e | 873 | mutex_unlock(&priv->lock); |
ab31523c | 874 | return err; |
90b6f305 | 875 | |
a93e20a8 | 876 | out_unlock_put: |
1401c00e | 877 | mutex_unlock(&priv->lock); |
90b6f305 | 878 | out_put_map: |
84e4075d DDG |
879 | if (use_ptemod) |
880 | map->vma = NULL; | |
16a1d022 | 881 | gntdev_put_map(priv, map); |
90b6f305 | 882 | return err; |
ab31523c GH |
883 | } |
884 | ||
885 | static const struct file_operations gntdev_fops = { | |
886 | .owner = THIS_MODULE, | |
887 | .open = gntdev_open, | |
888 | .release = gntdev_release, | |
889 | .mmap = gntdev_mmap, | |
890 | .unlocked_ioctl = gntdev_ioctl | |
891 | }; | |
892 | ||
893 | static struct miscdevice gntdev_miscdev = { | |
894 | .minor = MISC_DYNAMIC_MINOR, | |
895 | .name = "xen/gntdev", | |
896 | .fops = &gntdev_fops, | |
897 | }; | |
898 | ||
899 | /* ------------------------------------------------------------------ */ | |
900 | ||
901 | static int __init gntdev_init(void) | |
902 | { | |
903 | int err; | |
904 | ||
905 | if (!xen_domain()) | |
906 | return -ENODEV; | |
907 | ||
6926f6d6 | 908 | use_ptemod = !xen_feature(XENFEAT_auto_translated_physmap); |
aab8f11a | 909 | |
ab31523c GH |
910 | err = misc_register(&gntdev_miscdev); |
911 | if (err != 0) { | |
283c0972 | 912 | pr_err("Could not register gntdev device\n"); |
ab31523c GH |
913 | return err; |
914 | } | |
915 | return 0; | |
916 | } | |
917 | ||
918 | static void __exit gntdev_exit(void) | |
919 | { | |
920 | misc_deregister(&gntdev_miscdev); | |
921 | } | |
922 | ||
923 | module_init(gntdev_init); | |
924 | module_exit(gntdev_exit); | |
925 | ||
926 | /* ------------------------------------------------------------------ */ |