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cba3345c AW |
1 | /* |
2 | * VFIO core | |
3 | * | |
4 | * Copyright (C) 2012 Red Hat, Inc. All rights reserved. | |
5 | * Author: Alex Williamson <alex.williamson@redhat.com> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
10 | * | |
11 | * Derived from original vfio: | |
12 | * Copyright 2010 Cisco Systems, Inc. All rights reserved. | |
13 | * Author: Tom Lyon, pugs@cisco.com | |
14 | */ | |
15 | ||
16 | #include <linux/cdev.h> | |
17 | #include <linux/compat.h> | |
18 | #include <linux/device.h> | |
19 | #include <linux/file.h> | |
20 | #include <linux/anon_inodes.h> | |
21 | #include <linux/fs.h> | |
22 | #include <linux/idr.h> | |
23 | #include <linux/iommu.h> | |
24 | #include <linux/list.h> | |
d1099901 | 25 | #include <linux/miscdevice.h> |
cba3345c AW |
26 | #include <linux/module.h> |
27 | #include <linux/mutex.h> | |
9587f44a | 28 | #include <linux/rwsem.h> |
cba3345c AW |
29 | #include <linux/sched.h> |
30 | #include <linux/slab.h> | |
664e9386 | 31 | #include <linux/stat.h> |
cba3345c AW |
32 | #include <linux/string.h> |
33 | #include <linux/uaccess.h> | |
34 | #include <linux/vfio.h> | |
35 | #include <linux/wait.h> | |
36 | ||
37 | #define DRIVER_VERSION "0.3" | |
38 | #define DRIVER_AUTHOR "Alex Williamson <alex.williamson@redhat.com>" | |
39 | #define DRIVER_DESC "VFIO - User Level meta-driver" | |
40 | ||
41 | static struct vfio { | |
42 | struct class *class; | |
43 | struct list_head iommu_drivers_list; | |
44 | struct mutex iommu_drivers_lock; | |
45 | struct list_head group_list; | |
46 | struct idr group_idr; | |
47 | struct mutex group_lock; | |
48 | struct cdev group_cdev; | |
d1099901 | 49 | dev_t group_devt; |
cba3345c AW |
50 | wait_queue_head_t release_q; |
51 | } vfio; | |
52 | ||
53 | struct vfio_iommu_driver { | |
54 | const struct vfio_iommu_driver_ops *ops; | |
55 | struct list_head vfio_next; | |
56 | }; | |
57 | ||
58 | struct vfio_container { | |
59 | struct kref kref; | |
60 | struct list_head group_list; | |
9587f44a | 61 | struct rw_semaphore group_lock; |
cba3345c AW |
62 | struct vfio_iommu_driver *iommu_driver; |
63 | void *iommu_data; | |
64 | }; | |
65 | ||
60720a0f AW |
66 | struct vfio_unbound_dev { |
67 | struct device *dev; | |
68 | struct list_head unbound_next; | |
69 | }; | |
70 | ||
cba3345c AW |
71 | struct vfio_group { |
72 | struct kref kref; | |
73 | int minor; | |
74 | atomic_t container_users; | |
75 | struct iommu_group *iommu_group; | |
76 | struct vfio_container *container; | |
77 | struct list_head device_list; | |
78 | struct mutex device_lock; | |
79 | struct device *dev; | |
80 | struct notifier_block nb; | |
81 | struct list_head vfio_next; | |
82 | struct list_head container_next; | |
60720a0f AW |
83 | struct list_head unbound_list; |
84 | struct mutex unbound_lock; | |
6d6768c6 | 85 | atomic_t opened; |
cba3345c AW |
86 | }; |
87 | ||
88 | struct vfio_device { | |
89 | struct kref kref; | |
90 | struct device *dev; | |
91 | const struct vfio_device_ops *ops; | |
92 | struct vfio_group *group; | |
93 | struct list_head group_next; | |
94 | void *device_data; | |
95 | }; | |
96 | ||
97 | /** | |
98 | * IOMMU driver registration | |
99 | */ | |
100 | int vfio_register_iommu_driver(const struct vfio_iommu_driver_ops *ops) | |
101 | { | |
102 | struct vfio_iommu_driver *driver, *tmp; | |
103 | ||
104 | driver = kzalloc(sizeof(*driver), GFP_KERNEL); | |
105 | if (!driver) | |
106 | return -ENOMEM; | |
107 | ||
108 | driver->ops = ops; | |
109 | ||
110 | mutex_lock(&vfio.iommu_drivers_lock); | |
111 | ||
112 | /* Check for duplicates */ | |
113 | list_for_each_entry(tmp, &vfio.iommu_drivers_list, vfio_next) { | |
114 | if (tmp->ops == ops) { | |
115 | mutex_unlock(&vfio.iommu_drivers_lock); | |
116 | kfree(driver); | |
117 | return -EINVAL; | |
118 | } | |
119 | } | |
120 | ||
121 | list_add(&driver->vfio_next, &vfio.iommu_drivers_list); | |
122 | ||
123 | mutex_unlock(&vfio.iommu_drivers_lock); | |
124 | ||
125 | return 0; | |
126 | } | |
127 | EXPORT_SYMBOL_GPL(vfio_register_iommu_driver); | |
128 | ||
129 | void vfio_unregister_iommu_driver(const struct vfio_iommu_driver_ops *ops) | |
130 | { | |
131 | struct vfio_iommu_driver *driver; | |
132 | ||
133 | mutex_lock(&vfio.iommu_drivers_lock); | |
134 | list_for_each_entry(driver, &vfio.iommu_drivers_list, vfio_next) { | |
135 | if (driver->ops == ops) { | |
136 | list_del(&driver->vfio_next); | |
137 | mutex_unlock(&vfio.iommu_drivers_lock); | |
138 | kfree(driver); | |
139 | return; | |
140 | } | |
141 | } | |
142 | mutex_unlock(&vfio.iommu_drivers_lock); | |
143 | } | |
144 | EXPORT_SYMBOL_GPL(vfio_unregister_iommu_driver); | |
145 | ||
146 | /** | |
147 | * Group minor allocation/free - both called with vfio.group_lock held | |
148 | */ | |
149 | static int vfio_alloc_group_minor(struct vfio_group *group) | |
150 | { | |
d1099901 | 151 | return idr_alloc(&vfio.group_idr, group, 0, MINORMASK + 1, GFP_KERNEL); |
cba3345c AW |
152 | } |
153 | ||
154 | static void vfio_free_group_minor(int minor) | |
155 | { | |
156 | idr_remove(&vfio.group_idr, minor); | |
157 | } | |
158 | ||
159 | static int vfio_iommu_group_notifier(struct notifier_block *nb, | |
160 | unsigned long action, void *data); | |
161 | static void vfio_group_get(struct vfio_group *group); | |
162 | ||
163 | /** | |
164 | * Container objects - containers are created when /dev/vfio/vfio is | |
165 | * opened, but their lifecycle extends until the last user is done, so | |
166 | * it's freed via kref. Must support container/group/device being | |
167 | * closed in any order. | |
168 | */ | |
169 | static void vfio_container_get(struct vfio_container *container) | |
170 | { | |
171 | kref_get(&container->kref); | |
172 | } | |
173 | ||
174 | static void vfio_container_release(struct kref *kref) | |
175 | { | |
176 | struct vfio_container *container; | |
177 | container = container_of(kref, struct vfio_container, kref); | |
178 | ||
179 | kfree(container); | |
180 | } | |
181 | ||
182 | static void vfio_container_put(struct vfio_container *container) | |
183 | { | |
184 | kref_put(&container->kref, vfio_container_release); | |
185 | } | |
186 | ||
9df7b25a JL |
187 | static void vfio_group_unlock_and_free(struct vfio_group *group) |
188 | { | |
189 | mutex_unlock(&vfio.group_lock); | |
190 | /* | |
191 | * Unregister outside of lock. A spurious callback is harmless now | |
192 | * that the group is no longer in vfio.group_list. | |
193 | */ | |
194 | iommu_group_unregister_notifier(group->iommu_group, &group->nb); | |
195 | kfree(group); | |
196 | } | |
197 | ||
cba3345c AW |
198 | /** |
199 | * Group objects - create, release, get, put, search | |
200 | */ | |
201 | static struct vfio_group *vfio_create_group(struct iommu_group *iommu_group) | |
202 | { | |
203 | struct vfio_group *group, *tmp; | |
204 | struct device *dev; | |
205 | int ret, minor; | |
206 | ||
207 | group = kzalloc(sizeof(*group), GFP_KERNEL); | |
208 | if (!group) | |
209 | return ERR_PTR(-ENOMEM); | |
210 | ||
211 | kref_init(&group->kref); | |
212 | INIT_LIST_HEAD(&group->device_list); | |
213 | mutex_init(&group->device_lock); | |
60720a0f AW |
214 | INIT_LIST_HEAD(&group->unbound_list); |
215 | mutex_init(&group->unbound_lock); | |
cba3345c | 216 | atomic_set(&group->container_users, 0); |
6d6768c6 | 217 | atomic_set(&group->opened, 0); |
cba3345c AW |
218 | group->iommu_group = iommu_group; |
219 | ||
220 | group->nb.notifier_call = vfio_iommu_group_notifier; | |
221 | ||
222 | /* | |
223 | * blocking notifiers acquire a rwsem around registering and hold | |
224 | * it around callback. Therefore, need to register outside of | |
225 | * vfio.group_lock to avoid A-B/B-A contention. Our callback won't | |
226 | * do anything unless it can find the group in vfio.group_list, so | |
227 | * no harm in registering early. | |
228 | */ | |
229 | ret = iommu_group_register_notifier(iommu_group, &group->nb); | |
230 | if (ret) { | |
231 | kfree(group); | |
232 | return ERR_PTR(ret); | |
233 | } | |
234 | ||
235 | mutex_lock(&vfio.group_lock); | |
236 | ||
237 | minor = vfio_alloc_group_minor(group); | |
238 | if (minor < 0) { | |
9df7b25a | 239 | vfio_group_unlock_and_free(group); |
cba3345c AW |
240 | return ERR_PTR(minor); |
241 | } | |
242 | ||
243 | /* Did we race creating this group? */ | |
244 | list_for_each_entry(tmp, &vfio.group_list, vfio_next) { | |
245 | if (tmp->iommu_group == iommu_group) { | |
246 | vfio_group_get(tmp); | |
247 | vfio_free_group_minor(minor); | |
9df7b25a | 248 | vfio_group_unlock_and_free(group); |
cba3345c AW |
249 | return tmp; |
250 | } | |
251 | } | |
252 | ||
d1099901 AW |
253 | dev = device_create(vfio.class, NULL, |
254 | MKDEV(MAJOR(vfio.group_devt), minor), | |
cba3345c AW |
255 | group, "%d", iommu_group_id(iommu_group)); |
256 | if (IS_ERR(dev)) { | |
257 | vfio_free_group_minor(minor); | |
9df7b25a | 258 | vfio_group_unlock_and_free(group); |
cba3345c AW |
259 | return (struct vfio_group *)dev; /* ERR_PTR */ |
260 | } | |
261 | ||
262 | group->minor = minor; | |
263 | group->dev = dev; | |
264 | ||
265 | list_add(&group->vfio_next, &vfio.group_list); | |
266 | ||
267 | mutex_unlock(&vfio.group_lock); | |
268 | ||
269 | return group; | |
270 | } | |
271 | ||
6d2cd3ce | 272 | /* called with vfio.group_lock held */ |
cba3345c AW |
273 | static void vfio_group_release(struct kref *kref) |
274 | { | |
275 | struct vfio_group *group = container_of(kref, struct vfio_group, kref); | |
60720a0f | 276 | struct vfio_unbound_dev *unbound, *tmp; |
4a68810d | 277 | struct iommu_group *iommu_group = group->iommu_group; |
cba3345c AW |
278 | |
279 | WARN_ON(!list_empty(&group->device_list)); | |
280 | ||
60720a0f AW |
281 | list_for_each_entry_safe(unbound, tmp, |
282 | &group->unbound_list, unbound_next) { | |
283 | list_del(&unbound->unbound_next); | |
284 | kfree(unbound); | |
285 | } | |
286 | ||
d1099901 | 287 | device_destroy(vfio.class, MKDEV(MAJOR(vfio.group_devt), group->minor)); |
cba3345c AW |
288 | list_del(&group->vfio_next); |
289 | vfio_free_group_minor(group->minor); | |
9df7b25a | 290 | vfio_group_unlock_and_free(group); |
4a68810d | 291 | iommu_group_put(iommu_group); |
cba3345c AW |
292 | } |
293 | ||
294 | static void vfio_group_put(struct vfio_group *group) | |
295 | { | |
6d2cd3ce | 296 | kref_put_mutex(&group->kref, vfio_group_release, &vfio.group_lock); |
cba3345c AW |
297 | } |
298 | ||
299 | /* Assume group_lock or group reference is held */ | |
300 | static void vfio_group_get(struct vfio_group *group) | |
301 | { | |
302 | kref_get(&group->kref); | |
303 | } | |
304 | ||
305 | /* | |
306 | * Not really a try as we will sleep for mutex, but we need to make | |
307 | * sure the group pointer is valid under lock and get a reference. | |
308 | */ | |
309 | static struct vfio_group *vfio_group_try_get(struct vfio_group *group) | |
310 | { | |
311 | struct vfio_group *target = group; | |
312 | ||
313 | mutex_lock(&vfio.group_lock); | |
314 | list_for_each_entry(group, &vfio.group_list, vfio_next) { | |
315 | if (group == target) { | |
316 | vfio_group_get(group); | |
317 | mutex_unlock(&vfio.group_lock); | |
318 | return group; | |
319 | } | |
320 | } | |
321 | mutex_unlock(&vfio.group_lock); | |
322 | ||
323 | return NULL; | |
324 | } | |
325 | ||
326 | static | |
327 | struct vfio_group *vfio_group_get_from_iommu(struct iommu_group *iommu_group) | |
328 | { | |
329 | struct vfio_group *group; | |
330 | ||
331 | mutex_lock(&vfio.group_lock); | |
332 | list_for_each_entry(group, &vfio.group_list, vfio_next) { | |
333 | if (group->iommu_group == iommu_group) { | |
334 | vfio_group_get(group); | |
335 | mutex_unlock(&vfio.group_lock); | |
336 | return group; | |
337 | } | |
338 | } | |
339 | mutex_unlock(&vfio.group_lock); | |
340 | ||
341 | return NULL; | |
342 | } | |
343 | ||
344 | static struct vfio_group *vfio_group_get_from_minor(int minor) | |
345 | { | |
346 | struct vfio_group *group; | |
347 | ||
348 | mutex_lock(&vfio.group_lock); | |
349 | group = idr_find(&vfio.group_idr, minor); | |
350 | if (!group) { | |
351 | mutex_unlock(&vfio.group_lock); | |
352 | return NULL; | |
353 | } | |
354 | vfio_group_get(group); | |
355 | mutex_unlock(&vfio.group_lock); | |
356 | ||
357 | return group; | |
358 | } | |
359 | ||
360 | /** | |
361 | * Device objects - create, release, get, put, search | |
362 | */ | |
363 | static | |
364 | struct vfio_device *vfio_group_create_device(struct vfio_group *group, | |
365 | struct device *dev, | |
366 | const struct vfio_device_ops *ops, | |
367 | void *device_data) | |
368 | { | |
369 | struct vfio_device *device; | |
cba3345c AW |
370 | |
371 | device = kzalloc(sizeof(*device), GFP_KERNEL); | |
372 | if (!device) | |
373 | return ERR_PTR(-ENOMEM); | |
374 | ||
375 | kref_init(&device->kref); | |
376 | device->dev = dev; | |
377 | device->group = group; | |
378 | device->ops = ops; | |
379 | device->device_data = device_data; | |
8283b491 | 380 | dev_set_drvdata(dev, device); |
cba3345c AW |
381 | |
382 | /* No need to get group_lock, caller has group reference */ | |
383 | vfio_group_get(group); | |
384 | ||
385 | mutex_lock(&group->device_lock); | |
386 | list_add(&device->group_next, &group->device_list); | |
387 | mutex_unlock(&group->device_lock); | |
388 | ||
389 | return device; | |
390 | } | |
391 | ||
392 | static void vfio_device_release(struct kref *kref) | |
393 | { | |
394 | struct vfio_device *device = container_of(kref, | |
395 | struct vfio_device, kref); | |
396 | struct vfio_group *group = device->group; | |
397 | ||
cba3345c AW |
398 | list_del(&device->group_next); |
399 | mutex_unlock(&group->device_lock); | |
400 | ||
401 | dev_set_drvdata(device->dev, NULL); | |
402 | ||
403 | kfree(device); | |
404 | ||
405 | /* vfio_del_group_dev may be waiting for this device */ | |
406 | wake_up(&vfio.release_q); | |
407 | } | |
408 | ||
409 | /* Device reference always implies a group reference */ | |
44f50716 | 410 | void vfio_device_put(struct vfio_device *device) |
cba3345c | 411 | { |
934ad4c2 | 412 | struct vfio_group *group = device->group; |
90b1253e | 413 | kref_put_mutex(&device->kref, vfio_device_release, &group->device_lock); |
934ad4c2 | 414 | vfio_group_put(group); |
cba3345c | 415 | } |
44f50716 | 416 | EXPORT_SYMBOL_GPL(vfio_device_put); |
cba3345c AW |
417 | |
418 | static void vfio_device_get(struct vfio_device *device) | |
419 | { | |
420 | vfio_group_get(device->group); | |
421 | kref_get(&device->kref); | |
422 | } | |
423 | ||
424 | static struct vfio_device *vfio_group_get_device(struct vfio_group *group, | |
425 | struct device *dev) | |
426 | { | |
427 | struct vfio_device *device; | |
428 | ||
429 | mutex_lock(&group->device_lock); | |
430 | list_for_each_entry(device, &group->device_list, group_next) { | |
431 | if (device->dev == dev) { | |
432 | vfio_device_get(device); | |
433 | mutex_unlock(&group->device_lock); | |
434 | return device; | |
435 | } | |
436 | } | |
437 | mutex_unlock(&group->device_lock); | |
438 | return NULL; | |
439 | } | |
440 | ||
441 | /* | |
442 | * Whitelist some drivers that we know are safe (no dma) or just sit on | |
443 | * a device. It's not always practical to leave a device within a group | |
444 | * driverless as it could get re-bound to something unsafe. | |
445 | */ | |
2b489a45 | 446 | static const char * const vfio_driver_whitelist[] = { "pci-stub", "pcieport" }; |
cba3345c AW |
447 | |
448 | static bool vfio_whitelisted_driver(struct device_driver *drv) | |
449 | { | |
450 | int i; | |
451 | ||
452 | for (i = 0; i < ARRAY_SIZE(vfio_driver_whitelist); i++) { | |
453 | if (!strcmp(drv->name, vfio_driver_whitelist[i])) | |
454 | return true; | |
455 | } | |
456 | ||
457 | return false; | |
458 | } | |
459 | ||
460 | /* | |
60720a0f AW |
461 | * A vfio group is viable for use by userspace if all devices are in |
462 | * one of the following states: | |
463 | * - driver-less | |
464 | * - bound to a vfio driver | |
465 | * - bound to a whitelisted driver | |
466 | * | |
467 | * We use two methods to determine whether a device is bound to a vfio | |
468 | * driver. The first is to test whether the device exists in the vfio | |
469 | * group. The second is to test if the device exists on the group | |
470 | * unbound_list, indicating it's in the middle of transitioning from | |
471 | * a vfio driver to driver-less. | |
cba3345c AW |
472 | */ |
473 | static int vfio_dev_viable(struct device *dev, void *data) | |
474 | { | |
475 | struct vfio_group *group = data; | |
476 | struct vfio_device *device; | |
de2b3eea | 477 | struct device_driver *drv = ACCESS_ONCE(dev->driver); |
60720a0f AW |
478 | struct vfio_unbound_dev *unbound; |
479 | int ret = -EINVAL; | |
480 | ||
481 | mutex_lock(&group->unbound_lock); | |
482 | list_for_each_entry(unbound, &group->unbound_list, unbound_next) { | |
483 | if (dev == unbound->dev) { | |
484 | ret = 0; | |
485 | break; | |
486 | } | |
487 | } | |
488 | mutex_unlock(&group->unbound_lock); | |
cba3345c | 489 | |
60720a0f | 490 | if (!ret || !drv || vfio_whitelisted_driver(drv)) |
cba3345c AW |
491 | return 0; |
492 | ||
493 | device = vfio_group_get_device(group, dev); | |
494 | if (device) { | |
495 | vfio_device_put(device); | |
496 | return 0; | |
497 | } | |
498 | ||
60720a0f | 499 | return ret; |
cba3345c AW |
500 | } |
501 | ||
502 | /** | |
503 | * Async device support | |
504 | */ | |
505 | static int vfio_group_nb_add_dev(struct vfio_group *group, struct device *dev) | |
506 | { | |
507 | struct vfio_device *device; | |
508 | ||
509 | /* Do we already know about it? We shouldn't */ | |
510 | device = vfio_group_get_device(group, dev); | |
511 | if (WARN_ON_ONCE(device)) { | |
512 | vfio_device_put(device); | |
513 | return 0; | |
514 | } | |
515 | ||
516 | /* Nothing to do for idle groups */ | |
517 | if (!atomic_read(&group->container_users)) | |
518 | return 0; | |
519 | ||
520 | /* TODO Prevent device auto probing */ | |
521 | WARN("Device %s added to live group %d!\n", dev_name(dev), | |
522 | iommu_group_id(group->iommu_group)); | |
523 | ||
524 | return 0; | |
525 | } | |
526 | ||
cba3345c AW |
527 | static int vfio_group_nb_verify(struct vfio_group *group, struct device *dev) |
528 | { | |
529 | /* We don't care what happens when the group isn't in use */ | |
530 | if (!atomic_read(&group->container_users)) | |
531 | return 0; | |
532 | ||
533 | return vfio_dev_viable(dev, group); | |
534 | } | |
535 | ||
536 | static int vfio_iommu_group_notifier(struct notifier_block *nb, | |
537 | unsigned long action, void *data) | |
538 | { | |
539 | struct vfio_group *group = container_of(nb, struct vfio_group, nb); | |
540 | struct device *dev = data; | |
60720a0f | 541 | struct vfio_unbound_dev *unbound; |
cba3345c AW |
542 | |
543 | /* | |
c6401930 AW |
544 | * Need to go through a group_lock lookup to get a reference or we |
545 | * risk racing a group being removed. Ignore spurious notifies. | |
cba3345c AW |
546 | */ |
547 | group = vfio_group_try_get(group); | |
c6401930 | 548 | if (!group) |
cba3345c AW |
549 | return NOTIFY_OK; |
550 | ||
551 | switch (action) { | |
552 | case IOMMU_GROUP_NOTIFY_ADD_DEVICE: | |
553 | vfio_group_nb_add_dev(group, dev); | |
554 | break; | |
555 | case IOMMU_GROUP_NOTIFY_DEL_DEVICE: | |
de9c7602 AW |
556 | /* |
557 | * Nothing to do here. If the device is in use, then the | |
558 | * vfio sub-driver should block the remove callback until | |
559 | * it is unused. If the device is unused or attached to a | |
560 | * stub driver, then it should be released and we don't | |
561 | * care that it will be going away. | |
562 | */ | |
cba3345c AW |
563 | break; |
564 | case IOMMU_GROUP_NOTIFY_BIND_DRIVER: | |
565 | pr_debug("%s: Device %s, group %d binding to driver\n", | |
566 | __func__, dev_name(dev), | |
567 | iommu_group_id(group->iommu_group)); | |
568 | break; | |
569 | case IOMMU_GROUP_NOTIFY_BOUND_DRIVER: | |
570 | pr_debug("%s: Device %s, group %d bound to driver %s\n", | |
571 | __func__, dev_name(dev), | |
572 | iommu_group_id(group->iommu_group), dev->driver->name); | |
573 | BUG_ON(vfio_group_nb_verify(group, dev)); | |
574 | break; | |
575 | case IOMMU_GROUP_NOTIFY_UNBIND_DRIVER: | |
576 | pr_debug("%s: Device %s, group %d unbinding from driver %s\n", | |
577 | __func__, dev_name(dev), | |
578 | iommu_group_id(group->iommu_group), dev->driver->name); | |
579 | break; | |
580 | case IOMMU_GROUP_NOTIFY_UNBOUND_DRIVER: | |
581 | pr_debug("%s: Device %s, group %d unbound from driver\n", | |
582 | __func__, dev_name(dev), | |
583 | iommu_group_id(group->iommu_group)); | |
584 | /* | |
585 | * XXX An unbound device in a live group is ok, but we'd | |
586 | * really like to avoid the above BUG_ON by preventing other | |
587 | * drivers from binding to it. Once that occurs, we have to | |
588 | * stop the system to maintain isolation. At a minimum, we'd | |
589 | * want a toggle to disable driver auto probe for this device. | |
590 | */ | |
60720a0f AW |
591 | |
592 | mutex_lock(&group->unbound_lock); | |
593 | list_for_each_entry(unbound, | |
594 | &group->unbound_list, unbound_next) { | |
595 | if (dev == unbound->dev) { | |
596 | list_del(&unbound->unbound_next); | |
597 | kfree(unbound); | |
598 | break; | |
599 | } | |
600 | } | |
601 | mutex_unlock(&group->unbound_lock); | |
cba3345c AW |
602 | break; |
603 | } | |
604 | ||
605 | vfio_group_put(group); | |
606 | return NOTIFY_OK; | |
607 | } | |
608 | ||
609 | /** | |
610 | * VFIO driver API | |
611 | */ | |
612 | int vfio_add_group_dev(struct device *dev, | |
613 | const struct vfio_device_ops *ops, void *device_data) | |
614 | { | |
615 | struct iommu_group *iommu_group; | |
616 | struct vfio_group *group; | |
617 | struct vfio_device *device; | |
618 | ||
619 | iommu_group = iommu_group_get(dev); | |
620 | if (!iommu_group) | |
621 | return -EINVAL; | |
622 | ||
623 | group = vfio_group_get_from_iommu(iommu_group); | |
624 | if (!group) { | |
625 | group = vfio_create_group(iommu_group); | |
626 | if (IS_ERR(group)) { | |
627 | iommu_group_put(iommu_group); | |
628 | return PTR_ERR(group); | |
629 | } | |
4a68810d AW |
630 | } else { |
631 | /* | |
632 | * A found vfio_group already holds a reference to the | |
633 | * iommu_group. A created vfio_group keeps the reference. | |
634 | */ | |
635 | iommu_group_put(iommu_group); | |
cba3345c AW |
636 | } |
637 | ||
638 | device = vfio_group_get_device(group, dev); | |
639 | if (device) { | |
640 | WARN(1, "Device %s already exists on group %d\n", | |
641 | dev_name(dev), iommu_group_id(iommu_group)); | |
642 | vfio_device_put(device); | |
643 | vfio_group_put(group); | |
cba3345c AW |
644 | return -EBUSY; |
645 | } | |
646 | ||
647 | device = vfio_group_create_device(group, dev, ops, device_data); | |
648 | if (IS_ERR(device)) { | |
649 | vfio_group_put(group); | |
cba3345c AW |
650 | return PTR_ERR(device); |
651 | } | |
652 | ||
653 | /* | |
4a68810d AW |
654 | * Drop all but the vfio_device reference. The vfio_device holds |
655 | * a reference to the vfio_group, which holds a reference to the | |
656 | * iommu_group. | |
cba3345c AW |
657 | */ |
658 | vfio_group_put(group); | |
659 | ||
660 | return 0; | |
661 | } | |
662 | EXPORT_SYMBOL_GPL(vfio_add_group_dev); | |
663 | ||
44f50716 VMP |
664 | /** |
665 | * Get a reference to the vfio_device for a device that is known to | |
666 | * be bound to a vfio driver. The driver implicitly holds a | |
667 | * vfio_device reference between vfio_add_group_dev and | |
668 | * vfio_del_group_dev. We can therefore use drvdata to increment | |
669 | * that reference from the struct device. This additional | |
670 | * reference must be released by calling vfio_device_put. | |
671 | */ | |
672 | struct vfio_device *vfio_device_get_from_dev(struct device *dev) | |
673 | { | |
674 | struct vfio_device *device = dev_get_drvdata(dev); | |
675 | ||
676 | vfio_device_get(device); | |
677 | ||
678 | return device; | |
679 | } | |
680 | EXPORT_SYMBOL_GPL(vfio_device_get_from_dev); | |
681 | ||
682 | /* | |
683 | * Caller must hold a reference to the vfio_device | |
684 | */ | |
685 | void *vfio_device_data(struct vfio_device *device) | |
686 | { | |
687 | return device->device_data; | |
688 | } | |
689 | EXPORT_SYMBOL_GPL(vfio_device_data); | |
690 | ||
e014e944 AW |
691 | /* Given a referenced group, check if it contains the device */ |
692 | static bool vfio_dev_present(struct vfio_group *group, struct device *dev) | |
cba3345c | 693 | { |
cba3345c AW |
694 | struct vfio_device *device; |
695 | ||
cba3345c | 696 | device = vfio_group_get_device(group, dev); |
e014e944 | 697 | if (!device) |
cba3345c | 698 | return false; |
cba3345c AW |
699 | |
700 | vfio_device_put(device); | |
cba3345c AW |
701 | return true; |
702 | } | |
703 | ||
704 | /* | |
705 | * Decrement the device reference count and wait for the device to be | |
706 | * removed. Open file descriptors for the device... */ | |
707 | void *vfio_del_group_dev(struct device *dev) | |
708 | { | |
709 | struct vfio_device *device = dev_get_drvdata(dev); | |
710 | struct vfio_group *group = device->group; | |
cba3345c | 711 | void *device_data = device->device_data; |
60720a0f | 712 | struct vfio_unbound_dev *unbound; |
cba3345c | 713 | |
e014e944 AW |
714 | /* |
715 | * The group exists so long as we have a device reference. Get | |
716 | * a group reference and use it to scan for the device going away. | |
717 | */ | |
718 | vfio_group_get(group); | |
719 | ||
60720a0f AW |
720 | /* |
721 | * When the device is removed from the group, the group suddenly | |
722 | * becomes non-viable; the device has a driver (until the unbind | |
723 | * completes), but it's not present in the group. This is bad news | |
724 | * for any external users that need to re-acquire a group reference | |
725 | * in order to match and release their existing reference. To | |
726 | * solve this, we track such devices on the unbound_list to bridge | |
727 | * the gap until they're fully unbound. | |
728 | */ | |
729 | unbound = kzalloc(sizeof(*unbound), GFP_KERNEL); | |
730 | if (unbound) { | |
731 | unbound->dev = dev; | |
732 | mutex_lock(&group->unbound_lock); | |
733 | list_add(&unbound->unbound_next, &group->unbound_list); | |
734 | mutex_unlock(&group->unbound_lock); | |
735 | } | |
736 | WARN_ON(!unbound); | |
737 | ||
cba3345c AW |
738 | vfio_device_put(device); |
739 | ||
740 | /* TODO send a signal to encourage this to be released */ | |
e014e944 AW |
741 | wait_event(vfio.release_q, !vfio_dev_present(group, dev)); |
742 | ||
743 | vfio_group_put(group); | |
cba3345c | 744 | |
cba3345c AW |
745 | return device_data; |
746 | } | |
747 | EXPORT_SYMBOL_GPL(vfio_del_group_dev); | |
748 | ||
749 | /** | |
750 | * VFIO base fd, /dev/vfio/vfio | |
751 | */ | |
752 | static long vfio_ioctl_check_extension(struct vfio_container *container, | |
753 | unsigned long arg) | |
754 | { | |
0b43c082 | 755 | struct vfio_iommu_driver *driver; |
cba3345c AW |
756 | long ret = 0; |
757 | ||
0b43c082 AW |
758 | down_read(&container->group_lock); |
759 | ||
760 | driver = container->iommu_driver; | |
761 | ||
cba3345c AW |
762 | switch (arg) { |
763 | /* No base extensions yet */ | |
764 | default: | |
765 | /* | |
766 | * If no driver is set, poll all registered drivers for | |
767 | * extensions and return the first positive result. If | |
768 | * a driver is already set, further queries will be passed | |
769 | * only to that driver. | |
770 | */ | |
771 | if (!driver) { | |
772 | mutex_lock(&vfio.iommu_drivers_lock); | |
773 | list_for_each_entry(driver, &vfio.iommu_drivers_list, | |
774 | vfio_next) { | |
775 | if (!try_module_get(driver->ops->owner)) | |
776 | continue; | |
777 | ||
778 | ret = driver->ops->ioctl(NULL, | |
779 | VFIO_CHECK_EXTENSION, | |
780 | arg); | |
781 | module_put(driver->ops->owner); | |
782 | if (ret > 0) | |
783 | break; | |
784 | } | |
785 | mutex_unlock(&vfio.iommu_drivers_lock); | |
786 | } else | |
787 | ret = driver->ops->ioctl(container->iommu_data, | |
788 | VFIO_CHECK_EXTENSION, arg); | |
789 | } | |
790 | ||
0b43c082 AW |
791 | up_read(&container->group_lock); |
792 | ||
cba3345c AW |
793 | return ret; |
794 | } | |
795 | ||
9587f44a | 796 | /* hold write lock on container->group_lock */ |
cba3345c AW |
797 | static int __vfio_container_attach_groups(struct vfio_container *container, |
798 | struct vfio_iommu_driver *driver, | |
799 | void *data) | |
800 | { | |
801 | struct vfio_group *group; | |
802 | int ret = -ENODEV; | |
803 | ||
804 | list_for_each_entry(group, &container->group_list, container_next) { | |
805 | ret = driver->ops->attach_group(data, group->iommu_group); | |
806 | if (ret) | |
807 | goto unwind; | |
808 | } | |
809 | ||
810 | return ret; | |
811 | ||
812 | unwind: | |
813 | list_for_each_entry_continue_reverse(group, &container->group_list, | |
814 | container_next) { | |
815 | driver->ops->detach_group(data, group->iommu_group); | |
816 | } | |
817 | ||
818 | return ret; | |
819 | } | |
820 | ||
821 | static long vfio_ioctl_set_iommu(struct vfio_container *container, | |
822 | unsigned long arg) | |
823 | { | |
824 | struct vfio_iommu_driver *driver; | |
825 | long ret = -ENODEV; | |
826 | ||
9587f44a | 827 | down_write(&container->group_lock); |
cba3345c AW |
828 | |
829 | /* | |
830 | * The container is designed to be an unprivileged interface while | |
831 | * the group can be assigned to specific users. Therefore, only by | |
832 | * adding a group to a container does the user get the privilege of | |
833 | * enabling the iommu, which may allocate finite resources. There | |
834 | * is no unset_iommu, but by removing all the groups from a container, | |
835 | * the container is deprivileged and returns to an unset state. | |
836 | */ | |
837 | if (list_empty(&container->group_list) || container->iommu_driver) { | |
9587f44a | 838 | up_write(&container->group_lock); |
cba3345c AW |
839 | return -EINVAL; |
840 | } | |
841 | ||
842 | mutex_lock(&vfio.iommu_drivers_lock); | |
843 | list_for_each_entry(driver, &vfio.iommu_drivers_list, vfio_next) { | |
844 | void *data; | |
845 | ||
846 | if (!try_module_get(driver->ops->owner)) | |
847 | continue; | |
848 | ||
849 | /* | |
850 | * The arg magic for SET_IOMMU is the same as CHECK_EXTENSION, | |
851 | * so test which iommu driver reported support for this | |
852 | * extension and call open on them. We also pass them the | |
853 | * magic, allowing a single driver to support multiple | |
854 | * interfaces if they'd like. | |
855 | */ | |
856 | if (driver->ops->ioctl(NULL, VFIO_CHECK_EXTENSION, arg) <= 0) { | |
857 | module_put(driver->ops->owner); | |
858 | continue; | |
859 | } | |
860 | ||
861 | /* module reference holds the driver we're working on */ | |
862 | mutex_unlock(&vfio.iommu_drivers_lock); | |
863 | ||
864 | data = driver->ops->open(arg); | |
865 | if (IS_ERR(data)) { | |
866 | ret = PTR_ERR(data); | |
867 | module_put(driver->ops->owner); | |
868 | goto skip_drivers_unlock; | |
869 | } | |
870 | ||
871 | ret = __vfio_container_attach_groups(container, driver, data); | |
872 | if (!ret) { | |
873 | container->iommu_driver = driver; | |
874 | container->iommu_data = data; | |
875 | } else { | |
876 | driver->ops->release(data); | |
877 | module_put(driver->ops->owner); | |
878 | } | |
879 | ||
880 | goto skip_drivers_unlock; | |
881 | } | |
882 | ||
883 | mutex_unlock(&vfio.iommu_drivers_lock); | |
884 | skip_drivers_unlock: | |
9587f44a | 885 | up_write(&container->group_lock); |
cba3345c AW |
886 | |
887 | return ret; | |
888 | } | |
889 | ||
890 | static long vfio_fops_unl_ioctl(struct file *filep, | |
891 | unsigned int cmd, unsigned long arg) | |
892 | { | |
893 | struct vfio_container *container = filep->private_data; | |
894 | struct vfio_iommu_driver *driver; | |
895 | void *data; | |
896 | long ret = -EINVAL; | |
897 | ||
898 | if (!container) | |
899 | return ret; | |
900 | ||
cba3345c AW |
901 | switch (cmd) { |
902 | case VFIO_GET_API_VERSION: | |
903 | ret = VFIO_API_VERSION; | |
904 | break; | |
905 | case VFIO_CHECK_EXTENSION: | |
906 | ret = vfio_ioctl_check_extension(container, arg); | |
907 | break; | |
908 | case VFIO_SET_IOMMU: | |
909 | ret = vfio_ioctl_set_iommu(container, arg); | |
910 | break; | |
911 | default: | |
0b43c082 AW |
912 | down_read(&container->group_lock); |
913 | ||
914 | driver = container->iommu_driver; | |
915 | data = container->iommu_data; | |
916 | ||
cba3345c AW |
917 | if (driver) /* passthrough all unrecognized ioctls */ |
918 | ret = driver->ops->ioctl(data, cmd, arg); | |
0b43c082 AW |
919 | |
920 | up_read(&container->group_lock); | |
cba3345c AW |
921 | } |
922 | ||
923 | return ret; | |
924 | } | |
925 | ||
926 | #ifdef CONFIG_COMPAT | |
927 | static long vfio_fops_compat_ioctl(struct file *filep, | |
928 | unsigned int cmd, unsigned long arg) | |
929 | { | |
930 | arg = (unsigned long)compat_ptr(arg); | |
931 | return vfio_fops_unl_ioctl(filep, cmd, arg); | |
932 | } | |
933 | #endif /* CONFIG_COMPAT */ | |
934 | ||
935 | static int vfio_fops_open(struct inode *inode, struct file *filep) | |
936 | { | |
937 | struct vfio_container *container; | |
938 | ||
939 | container = kzalloc(sizeof(*container), GFP_KERNEL); | |
940 | if (!container) | |
941 | return -ENOMEM; | |
942 | ||
943 | INIT_LIST_HEAD(&container->group_list); | |
9587f44a | 944 | init_rwsem(&container->group_lock); |
cba3345c AW |
945 | kref_init(&container->kref); |
946 | ||
947 | filep->private_data = container; | |
948 | ||
949 | return 0; | |
950 | } | |
951 | ||
952 | static int vfio_fops_release(struct inode *inode, struct file *filep) | |
953 | { | |
954 | struct vfio_container *container = filep->private_data; | |
955 | ||
956 | filep->private_data = NULL; | |
957 | ||
958 | vfio_container_put(container); | |
959 | ||
960 | return 0; | |
961 | } | |
962 | ||
963 | /* | |
964 | * Once an iommu driver is set, we optionally pass read/write/mmap | |
965 | * on to the driver, allowing management interfaces beyond ioctl. | |
966 | */ | |
967 | static ssize_t vfio_fops_read(struct file *filep, char __user *buf, | |
968 | size_t count, loff_t *ppos) | |
969 | { | |
970 | struct vfio_container *container = filep->private_data; | |
0b43c082 AW |
971 | struct vfio_iommu_driver *driver; |
972 | ssize_t ret = -EINVAL; | |
cba3345c | 973 | |
0b43c082 AW |
974 | down_read(&container->group_lock); |
975 | ||
976 | driver = container->iommu_driver; | |
977 | if (likely(driver && driver->ops->read)) | |
978 | ret = driver->ops->read(container->iommu_data, | |
979 | buf, count, ppos); | |
cba3345c | 980 | |
0b43c082 AW |
981 | up_read(&container->group_lock); |
982 | ||
983 | return ret; | |
cba3345c AW |
984 | } |
985 | ||
986 | static ssize_t vfio_fops_write(struct file *filep, const char __user *buf, | |
987 | size_t count, loff_t *ppos) | |
988 | { | |
989 | struct vfio_container *container = filep->private_data; | |
0b43c082 AW |
990 | struct vfio_iommu_driver *driver; |
991 | ssize_t ret = -EINVAL; | |
cba3345c | 992 | |
0b43c082 AW |
993 | down_read(&container->group_lock); |
994 | ||
995 | driver = container->iommu_driver; | |
996 | if (likely(driver && driver->ops->write)) | |
997 | ret = driver->ops->write(container->iommu_data, | |
998 | buf, count, ppos); | |
999 | ||
1000 | up_read(&container->group_lock); | |
cba3345c | 1001 | |
0b43c082 | 1002 | return ret; |
cba3345c AW |
1003 | } |
1004 | ||
1005 | static int vfio_fops_mmap(struct file *filep, struct vm_area_struct *vma) | |
1006 | { | |
1007 | struct vfio_container *container = filep->private_data; | |
0b43c082 AW |
1008 | struct vfio_iommu_driver *driver; |
1009 | int ret = -EINVAL; | |
cba3345c | 1010 | |
0b43c082 | 1011 | down_read(&container->group_lock); |
cba3345c | 1012 | |
0b43c082 AW |
1013 | driver = container->iommu_driver; |
1014 | if (likely(driver && driver->ops->mmap)) | |
1015 | ret = driver->ops->mmap(container->iommu_data, vma); | |
1016 | ||
1017 | up_read(&container->group_lock); | |
1018 | ||
1019 | return ret; | |
cba3345c AW |
1020 | } |
1021 | ||
1022 | static const struct file_operations vfio_fops = { | |
1023 | .owner = THIS_MODULE, | |
1024 | .open = vfio_fops_open, | |
1025 | .release = vfio_fops_release, | |
1026 | .read = vfio_fops_read, | |
1027 | .write = vfio_fops_write, | |
1028 | .unlocked_ioctl = vfio_fops_unl_ioctl, | |
1029 | #ifdef CONFIG_COMPAT | |
1030 | .compat_ioctl = vfio_fops_compat_ioctl, | |
1031 | #endif | |
1032 | .mmap = vfio_fops_mmap, | |
1033 | }; | |
1034 | ||
1035 | /** | |
1036 | * VFIO Group fd, /dev/vfio/$GROUP | |
1037 | */ | |
1038 | static void __vfio_group_unset_container(struct vfio_group *group) | |
1039 | { | |
1040 | struct vfio_container *container = group->container; | |
1041 | struct vfio_iommu_driver *driver; | |
1042 | ||
9587f44a | 1043 | down_write(&container->group_lock); |
cba3345c AW |
1044 | |
1045 | driver = container->iommu_driver; | |
1046 | if (driver) | |
1047 | driver->ops->detach_group(container->iommu_data, | |
1048 | group->iommu_group); | |
1049 | ||
1050 | group->container = NULL; | |
1051 | list_del(&group->container_next); | |
1052 | ||
1053 | /* Detaching the last group deprivileges a container, remove iommu */ | |
1054 | if (driver && list_empty(&container->group_list)) { | |
1055 | driver->ops->release(container->iommu_data); | |
1056 | module_put(driver->ops->owner); | |
1057 | container->iommu_driver = NULL; | |
1058 | container->iommu_data = NULL; | |
1059 | } | |
1060 | ||
9587f44a | 1061 | up_write(&container->group_lock); |
cba3345c AW |
1062 | |
1063 | vfio_container_put(container); | |
1064 | } | |
1065 | ||
1066 | /* | |
1067 | * VFIO_GROUP_UNSET_CONTAINER should fail if there are other users or | |
1068 | * if there was no container to unset. Since the ioctl is called on | |
1069 | * the group, we know that still exists, therefore the only valid | |
1070 | * transition here is 1->0. | |
1071 | */ | |
1072 | static int vfio_group_unset_container(struct vfio_group *group) | |
1073 | { | |
1074 | int users = atomic_cmpxchg(&group->container_users, 1, 0); | |
1075 | ||
1076 | if (!users) | |
1077 | return -EINVAL; | |
1078 | if (users != 1) | |
1079 | return -EBUSY; | |
1080 | ||
1081 | __vfio_group_unset_container(group); | |
1082 | ||
1083 | return 0; | |
1084 | } | |
1085 | ||
1086 | /* | |
1087 | * When removing container users, anything that removes the last user | |
1088 | * implicitly removes the group from the container. That is, if the | |
1089 | * group file descriptor is closed, as well as any device file descriptors, | |
1090 | * the group is free. | |
1091 | */ | |
1092 | static void vfio_group_try_dissolve_container(struct vfio_group *group) | |
1093 | { | |
1094 | if (0 == atomic_dec_if_positive(&group->container_users)) | |
1095 | __vfio_group_unset_container(group); | |
1096 | } | |
1097 | ||
1098 | static int vfio_group_set_container(struct vfio_group *group, int container_fd) | |
1099 | { | |
2903ff01 | 1100 | struct fd f; |
cba3345c AW |
1101 | struct vfio_container *container; |
1102 | struct vfio_iommu_driver *driver; | |
2903ff01 | 1103 | int ret = 0; |
cba3345c AW |
1104 | |
1105 | if (atomic_read(&group->container_users)) | |
1106 | return -EINVAL; | |
1107 | ||
2903ff01 AV |
1108 | f = fdget(container_fd); |
1109 | if (!f.file) | |
cba3345c AW |
1110 | return -EBADF; |
1111 | ||
1112 | /* Sanity check, is this really our fd? */ | |
2903ff01 AV |
1113 | if (f.file->f_op != &vfio_fops) { |
1114 | fdput(f); | |
cba3345c AW |
1115 | return -EINVAL; |
1116 | } | |
1117 | ||
2903ff01 | 1118 | container = f.file->private_data; |
cba3345c AW |
1119 | WARN_ON(!container); /* fget ensures we don't race vfio_release */ |
1120 | ||
9587f44a | 1121 | down_write(&container->group_lock); |
cba3345c AW |
1122 | |
1123 | driver = container->iommu_driver; | |
1124 | if (driver) { | |
1125 | ret = driver->ops->attach_group(container->iommu_data, | |
1126 | group->iommu_group); | |
1127 | if (ret) | |
1128 | goto unlock_out; | |
1129 | } | |
1130 | ||
1131 | group->container = container; | |
1132 | list_add(&group->container_next, &container->group_list); | |
1133 | ||
1134 | /* Get a reference on the container and mark a user within the group */ | |
1135 | vfio_container_get(container); | |
1136 | atomic_inc(&group->container_users); | |
1137 | ||
1138 | unlock_out: | |
9587f44a | 1139 | up_write(&container->group_lock); |
2903ff01 | 1140 | fdput(f); |
cba3345c AW |
1141 | return ret; |
1142 | } | |
1143 | ||
1144 | static bool vfio_group_viable(struct vfio_group *group) | |
1145 | { | |
1146 | return (iommu_group_for_each_dev(group->iommu_group, | |
1147 | group, vfio_dev_viable) == 0); | |
1148 | } | |
1149 | ||
1150 | static const struct file_operations vfio_device_fops; | |
1151 | ||
1152 | static int vfio_group_get_device_fd(struct vfio_group *group, char *buf) | |
1153 | { | |
1154 | struct vfio_device *device; | |
1155 | struct file *filep; | |
1156 | int ret = -ENODEV; | |
1157 | ||
1158 | if (0 == atomic_read(&group->container_users) || | |
1159 | !group->container->iommu_driver || !vfio_group_viable(group)) | |
1160 | return -EINVAL; | |
1161 | ||
1162 | mutex_lock(&group->device_lock); | |
1163 | list_for_each_entry(device, &group->device_list, group_next) { | |
1164 | if (strcmp(dev_name(device->dev), buf)) | |
1165 | continue; | |
1166 | ||
1167 | ret = device->ops->open(device->device_data); | |
1168 | if (ret) | |
1169 | break; | |
1170 | /* | |
1171 | * We can't use anon_inode_getfd() because we need to modify | |
1172 | * the f_mode flags directly to allow more than just ioctls | |
1173 | */ | |
5d042fbd | 1174 | ret = get_unused_fd_flags(O_CLOEXEC); |
cba3345c AW |
1175 | if (ret < 0) { |
1176 | device->ops->release(device->device_data); | |
1177 | break; | |
1178 | } | |
1179 | ||
1180 | filep = anon_inode_getfile("[vfio-device]", &vfio_device_fops, | |
1181 | device, O_RDWR); | |
1182 | if (IS_ERR(filep)) { | |
1183 | put_unused_fd(ret); | |
1184 | ret = PTR_ERR(filep); | |
1185 | device->ops->release(device->device_data); | |
1186 | break; | |
1187 | } | |
1188 | ||
1189 | /* | |
1190 | * TODO: add an anon_inode interface to do this. | |
1191 | * Appears to be missing by lack of need rather than | |
1192 | * explicitly prevented. Now there's need. | |
1193 | */ | |
1194 | filep->f_mode |= (FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE); | |
1195 | ||
cba3345c AW |
1196 | vfio_device_get(device); |
1197 | atomic_inc(&group->container_users); | |
31605deb AV |
1198 | |
1199 | fd_install(ret, filep); | |
cba3345c AW |
1200 | break; |
1201 | } | |
1202 | mutex_unlock(&group->device_lock); | |
1203 | ||
1204 | return ret; | |
1205 | } | |
1206 | ||
1207 | static long vfio_group_fops_unl_ioctl(struct file *filep, | |
1208 | unsigned int cmd, unsigned long arg) | |
1209 | { | |
1210 | struct vfio_group *group = filep->private_data; | |
1211 | long ret = -ENOTTY; | |
1212 | ||
1213 | switch (cmd) { | |
1214 | case VFIO_GROUP_GET_STATUS: | |
1215 | { | |
1216 | struct vfio_group_status status; | |
1217 | unsigned long minsz; | |
1218 | ||
1219 | minsz = offsetofend(struct vfio_group_status, flags); | |
1220 | ||
1221 | if (copy_from_user(&status, (void __user *)arg, minsz)) | |
1222 | return -EFAULT; | |
1223 | ||
1224 | if (status.argsz < minsz) | |
1225 | return -EINVAL; | |
1226 | ||
1227 | status.flags = 0; | |
1228 | ||
1229 | if (vfio_group_viable(group)) | |
1230 | status.flags |= VFIO_GROUP_FLAGS_VIABLE; | |
1231 | ||
1232 | if (group->container) | |
1233 | status.flags |= VFIO_GROUP_FLAGS_CONTAINER_SET; | |
1234 | ||
1235 | if (copy_to_user((void __user *)arg, &status, minsz)) | |
1236 | return -EFAULT; | |
1237 | ||
1238 | ret = 0; | |
1239 | break; | |
1240 | } | |
1241 | case VFIO_GROUP_SET_CONTAINER: | |
1242 | { | |
1243 | int fd; | |
1244 | ||
1245 | if (get_user(fd, (int __user *)arg)) | |
1246 | return -EFAULT; | |
1247 | ||
1248 | if (fd < 0) | |
1249 | return -EINVAL; | |
1250 | ||
1251 | ret = vfio_group_set_container(group, fd); | |
1252 | break; | |
1253 | } | |
1254 | case VFIO_GROUP_UNSET_CONTAINER: | |
1255 | ret = vfio_group_unset_container(group); | |
1256 | break; | |
1257 | case VFIO_GROUP_GET_DEVICE_FD: | |
1258 | { | |
1259 | char *buf; | |
1260 | ||
1261 | buf = strndup_user((const char __user *)arg, PAGE_SIZE); | |
1262 | if (IS_ERR(buf)) | |
1263 | return PTR_ERR(buf); | |
1264 | ||
1265 | ret = vfio_group_get_device_fd(group, buf); | |
1266 | kfree(buf); | |
1267 | break; | |
1268 | } | |
1269 | } | |
1270 | ||
1271 | return ret; | |
1272 | } | |
1273 | ||
1274 | #ifdef CONFIG_COMPAT | |
1275 | static long vfio_group_fops_compat_ioctl(struct file *filep, | |
1276 | unsigned int cmd, unsigned long arg) | |
1277 | { | |
1278 | arg = (unsigned long)compat_ptr(arg); | |
1279 | return vfio_group_fops_unl_ioctl(filep, cmd, arg); | |
1280 | } | |
1281 | #endif /* CONFIG_COMPAT */ | |
1282 | ||
1283 | static int vfio_group_fops_open(struct inode *inode, struct file *filep) | |
1284 | { | |
1285 | struct vfio_group *group; | |
6d6768c6 | 1286 | int opened; |
cba3345c AW |
1287 | |
1288 | group = vfio_group_get_from_minor(iminor(inode)); | |
1289 | if (!group) | |
1290 | return -ENODEV; | |
1291 | ||
6d6768c6 AW |
1292 | /* Do we need multiple instances of the group open? Seems not. */ |
1293 | opened = atomic_cmpxchg(&group->opened, 0, 1); | |
1294 | if (opened) { | |
1295 | vfio_group_put(group); | |
1296 | return -EBUSY; | |
1297 | } | |
1298 | ||
1299 | /* Is something still in use from a previous open? */ | |
cba3345c | 1300 | if (group->container) { |
6d6768c6 | 1301 | atomic_dec(&group->opened); |
cba3345c AW |
1302 | vfio_group_put(group); |
1303 | return -EBUSY; | |
1304 | } | |
1305 | ||
1306 | filep->private_data = group; | |
1307 | ||
1308 | return 0; | |
1309 | } | |
1310 | ||
1311 | static int vfio_group_fops_release(struct inode *inode, struct file *filep) | |
1312 | { | |
1313 | struct vfio_group *group = filep->private_data; | |
1314 | ||
1315 | filep->private_data = NULL; | |
1316 | ||
1317 | vfio_group_try_dissolve_container(group); | |
1318 | ||
6d6768c6 AW |
1319 | atomic_dec(&group->opened); |
1320 | ||
cba3345c AW |
1321 | vfio_group_put(group); |
1322 | ||
1323 | return 0; | |
1324 | } | |
1325 | ||
1326 | static const struct file_operations vfio_group_fops = { | |
1327 | .owner = THIS_MODULE, | |
1328 | .unlocked_ioctl = vfio_group_fops_unl_ioctl, | |
1329 | #ifdef CONFIG_COMPAT | |
1330 | .compat_ioctl = vfio_group_fops_compat_ioctl, | |
1331 | #endif | |
1332 | .open = vfio_group_fops_open, | |
1333 | .release = vfio_group_fops_release, | |
1334 | }; | |
1335 | ||
1336 | /** | |
1337 | * VFIO Device fd | |
1338 | */ | |
1339 | static int vfio_device_fops_release(struct inode *inode, struct file *filep) | |
1340 | { | |
1341 | struct vfio_device *device = filep->private_data; | |
1342 | ||
1343 | device->ops->release(device->device_data); | |
1344 | ||
1345 | vfio_group_try_dissolve_container(device->group); | |
1346 | ||
1347 | vfio_device_put(device); | |
1348 | ||
1349 | return 0; | |
1350 | } | |
1351 | ||
1352 | static long vfio_device_fops_unl_ioctl(struct file *filep, | |
1353 | unsigned int cmd, unsigned long arg) | |
1354 | { | |
1355 | struct vfio_device *device = filep->private_data; | |
1356 | ||
1357 | if (unlikely(!device->ops->ioctl)) | |
1358 | return -EINVAL; | |
1359 | ||
1360 | return device->ops->ioctl(device->device_data, cmd, arg); | |
1361 | } | |
1362 | ||
1363 | static ssize_t vfio_device_fops_read(struct file *filep, char __user *buf, | |
1364 | size_t count, loff_t *ppos) | |
1365 | { | |
1366 | struct vfio_device *device = filep->private_data; | |
1367 | ||
1368 | if (unlikely(!device->ops->read)) | |
1369 | return -EINVAL; | |
1370 | ||
1371 | return device->ops->read(device->device_data, buf, count, ppos); | |
1372 | } | |
1373 | ||
1374 | static ssize_t vfio_device_fops_write(struct file *filep, | |
1375 | const char __user *buf, | |
1376 | size_t count, loff_t *ppos) | |
1377 | { | |
1378 | struct vfio_device *device = filep->private_data; | |
1379 | ||
1380 | if (unlikely(!device->ops->write)) | |
1381 | return -EINVAL; | |
1382 | ||
1383 | return device->ops->write(device->device_data, buf, count, ppos); | |
1384 | } | |
1385 | ||
1386 | static int vfio_device_fops_mmap(struct file *filep, struct vm_area_struct *vma) | |
1387 | { | |
1388 | struct vfio_device *device = filep->private_data; | |
1389 | ||
1390 | if (unlikely(!device->ops->mmap)) | |
1391 | return -EINVAL; | |
1392 | ||
1393 | return device->ops->mmap(device->device_data, vma); | |
1394 | } | |
1395 | ||
1396 | #ifdef CONFIG_COMPAT | |
1397 | static long vfio_device_fops_compat_ioctl(struct file *filep, | |
1398 | unsigned int cmd, unsigned long arg) | |
1399 | { | |
1400 | arg = (unsigned long)compat_ptr(arg); | |
1401 | return vfio_device_fops_unl_ioctl(filep, cmd, arg); | |
1402 | } | |
1403 | #endif /* CONFIG_COMPAT */ | |
1404 | ||
1405 | static const struct file_operations vfio_device_fops = { | |
1406 | .owner = THIS_MODULE, | |
1407 | .release = vfio_device_fops_release, | |
1408 | .read = vfio_device_fops_read, | |
1409 | .write = vfio_device_fops_write, | |
1410 | .unlocked_ioctl = vfio_device_fops_unl_ioctl, | |
1411 | #ifdef CONFIG_COMPAT | |
1412 | .compat_ioctl = vfio_device_fops_compat_ioctl, | |
1413 | #endif | |
1414 | .mmap = vfio_device_fops_mmap, | |
1415 | }; | |
1416 | ||
6cdd9782 AK |
1417 | /** |
1418 | * External user API, exported by symbols to be linked dynamically. | |
1419 | * | |
1420 | * The protocol includes: | |
1421 | * 1. do normal VFIO init operation: | |
1422 | * - opening a new container; | |
1423 | * - attaching group(s) to it; | |
1424 | * - setting an IOMMU driver for a container. | |
1425 | * When IOMMU is set for a container, all groups in it are | |
1426 | * considered ready to use by an external user. | |
1427 | * | |
1428 | * 2. User space passes a group fd to an external user. | |
1429 | * The external user calls vfio_group_get_external_user() | |
1430 | * to verify that: | |
1431 | * - the group is initialized; | |
1432 | * - IOMMU is set for it. | |
1433 | * If both checks passed, vfio_group_get_external_user() | |
1434 | * increments the container user counter to prevent | |
1435 | * the VFIO group from disposal before KVM exits. | |
1436 | * | |
1437 | * 3. The external user calls vfio_external_user_iommu_id() | |
1438 | * to know an IOMMU ID. | |
1439 | * | |
1440 | * 4. When the external KVM finishes, it calls | |
1441 | * vfio_group_put_external_user() to release the VFIO group. | |
1442 | * This call decrements the container user counter. | |
1443 | */ | |
1444 | struct vfio_group *vfio_group_get_external_user(struct file *filep) | |
1445 | { | |
1446 | struct vfio_group *group = filep->private_data; | |
1447 | ||
1448 | if (filep->f_op != &vfio_group_fops) | |
1449 | return ERR_PTR(-EINVAL); | |
1450 | ||
1451 | if (!atomic_inc_not_zero(&group->container_users)) | |
1452 | return ERR_PTR(-EINVAL); | |
1453 | ||
1454 | if (!group->container->iommu_driver || | |
1455 | !vfio_group_viable(group)) { | |
1456 | atomic_dec(&group->container_users); | |
1457 | return ERR_PTR(-EINVAL); | |
1458 | } | |
1459 | ||
1460 | vfio_group_get(group); | |
1461 | ||
1462 | return group; | |
1463 | } | |
1464 | EXPORT_SYMBOL_GPL(vfio_group_get_external_user); | |
1465 | ||
1466 | void vfio_group_put_external_user(struct vfio_group *group) | |
1467 | { | |
1468 | vfio_group_put(group); | |
1469 | vfio_group_try_dissolve_container(group); | |
1470 | } | |
1471 | EXPORT_SYMBOL_GPL(vfio_group_put_external_user); | |
1472 | ||
1473 | int vfio_external_user_iommu_id(struct vfio_group *group) | |
1474 | { | |
1475 | return iommu_group_id(group->iommu_group); | |
1476 | } | |
1477 | EXPORT_SYMBOL_GPL(vfio_external_user_iommu_id); | |
1478 | ||
88d7ab89 AW |
1479 | long vfio_external_check_extension(struct vfio_group *group, unsigned long arg) |
1480 | { | |
1481 | return vfio_ioctl_check_extension(group->container, arg); | |
1482 | } | |
1483 | EXPORT_SYMBOL_GPL(vfio_external_check_extension); | |
1484 | ||
cba3345c AW |
1485 | /** |
1486 | * Module/class support | |
1487 | */ | |
1488 | static char *vfio_devnode(struct device *dev, umode_t *mode) | |
1489 | { | |
1490 | return kasprintf(GFP_KERNEL, "vfio/%s", dev_name(dev)); | |
1491 | } | |
1492 | ||
d1099901 AW |
1493 | static struct miscdevice vfio_dev = { |
1494 | .minor = VFIO_MINOR, | |
1495 | .name = "vfio", | |
1496 | .fops = &vfio_fops, | |
1497 | .nodename = "vfio/vfio", | |
1498 | .mode = S_IRUGO | S_IWUGO, | |
1499 | }; | |
1500 | ||
cba3345c AW |
1501 | static int __init vfio_init(void) |
1502 | { | |
1503 | int ret; | |
1504 | ||
1505 | idr_init(&vfio.group_idr); | |
1506 | mutex_init(&vfio.group_lock); | |
1507 | mutex_init(&vfio.iommu_drivers_lock); | |
1508 | INIT_LIST_HEAD(&vfio.group_list); | |
1509 | INIT_LIST_HEAD(&vfio.iommu_drivers_list); | |
1510 | init_waitqueue_head(&vfio.release_q); | |
1511 | ||
d1099901 AW |
1512 | ret = misc_register(&vfio_dev); |
1513 | if (ret) { | |
1514 | pr_err("vfio: misc device register failed\n"); | |
1515 | return ret; | |
1516 | } | |
1517 | ||
1518 | /* /dev/vfio/$GROUP */ | |
cba3345c AW |
1519 | vfio.class = class_create(THIS_MODULE, "vfio"); |
1520 | if (IS_ERR(vfio.class)) { | |
1521 | ret = PTR_ERR(vfio.class); | |
1522 | goto err_class; | |
1523 | } | |
1524 | ||
1525 | vfio.class->devnode = vfio_devnode; | |
1526 | ||
d1099901 | 1527 | ret = alloc_chrdev_region(&vfio.group_devt, 0, MINORMASK, "vfio"); |
cba3345c | 1528 | if (ret) |
d1099901 | 1529 | goto err_alloc_chrdev; |
cba3345c | 1530 | |
cba3345c | 1531 | cdev_init(&vfio.group_cdev, &vfio_group_fops); |
d1099901 | 1532 | ret = cdev_add(&vfio.group_cdev, vfio.group_devt, MINORMASK); |
cba3345c | 1533 | if (ret) |
d1099901 | 1534 | goto err_cdev_add; |
cba3345c AW |
1535 | |
1536 | pr_info(DRIVER_DESC " version: " DRIVER_VERSION "\n"); | |
1537 | ||
73fa0d10 AW |
1538 | /* |
1539 | * Attempt to load known iommu-drivers. This gives us a working | |
1540 | * environment without the user needing to explicitly load iommu | |
1541 | * drivers. | |
1542 | */ | |
1543 | request_module_nowait("vfio_iommu_type1"); | |
5ffd229c | 1544 | request_module_nowait("vfio_iommu_spapr_tce"); |
73fa0d10 | 1545 | |
cba3345c AW |
1546 | return 0; |
1547 | ||
d1099901 AW |
1548 | err_cdev_add: |
1549 | unregister_chrdev_region(vfio.group_devt, MINORMASK); | |
1550 | err_alloc_chrdev: | |
cba3345c AW |
1551 | class_destroy(vfio.class); |
1552 | vfio.class = NULL; | |
1553 | err_class: | |
d1099901 | 1554 | misc_deregister(&vfio_dev); |
cba3345c AW |
1555 | return ret; |
1556 | } | |
1557 | ||
1558 | static void __exit vfio_cleanup(void) | |
1559 | { | |
1560 | WARN_ON(!list_empty(&vfio.group_list)); | |
1561 | ||
1562 | idr_destroy(&vfio.group_idr); | |
1563 | cdev_del(&vfio.group_cdev); | |
d1099901 | 1564 | unregister_chrdev_region(vfio.group_devt, MINORMASK); |
cba3345c AW |
1565 | class_destroy(vfio.class); |
1566 | vfio.class = NULL; | |
d1099901 | 1567 | misc_deregister(&vfio_dev); |
cba3345c AW |
1568 | } |
1569 | ||
1570 | module_init(vfio_init); | |
1571 | module_exit(vfio_cleanup); | |
1572 | ||
1573 | MODULE_VERSION(DRIVER_VERSION); | |
1574 | MODULE_LICENSE("GPL v2"); | |
1575 | MODULE_AUTHOR(DRIVER_AUTHOR); | |
1576 | MODULE_DESCRIPTION(DRIVER_DESC); | |
d1099901 AW |
1577 | MODULE_ALIAS_MISCDEV(VFIO_MINOR); |
1578 | MODULE_ALIAS("devname:vfio/vfio"); |