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-rw-r--r--drivers/Kconfig2
-rw-r--r--drivers/Makefile1
-rw-r--r--drivers/vfio/Kconfig8
-rw-r--r--drivers/vfio/Makefile1
-rw-r--r--drivers/vfio/vfio.c1413
5 files changed, 1425 insertions, 0 deletions
diff --git a/drivers/Kconfig b/drivers/Kconfig
index 805c432c9439..ece958d3762e 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -112,6 +112,8 @@ source "drivers/auxdisplay/Kconfig"
112 112
113source "drivers/uio/Kconfig" 113source "drivers/uio/Kconfig"
114 114
115source "drivers/vfio/Kconfig"
116
115source "drivers/vlynq/Kconfig" 117source "drivers/vlynq/Kconfig"
116 118
117source "drivers/virtio/Kconfig" 119source "drivers/virtio/Kconfig"
diff --git a/drivers/Makefile b/drivers/Makefile
index bd36f09f2246..5b421840c48d 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -60,6 +60,7 @@ obj-$(CONFIG_ATM) += atm/
60obj-$(CONFIG_FUSION) += message/ 60obj-$(CONFIG_FUSION) += message/
61obj-y += firewire/ 61obj-y += firewire/
62obj-$(CONFIG_UIO) += uio/ 62obj-$(CONFIG_UIO) += uio/
63obj-$(CONFIG_VFIO) += vfio/
63obj-y += cdrom/ 64obj-y += cdrom/
64obj-y += auxdisplay/ 65obj-y += auxdisplay/
65obj-$(CONFIG_PCCARD) += pcmcia/ 66obj-$(CONFIG_PCCARD) += pcmcia/
diff --git a/drivers/vfio/Kconfig b/drivers/vfio/Kconfig
new file mode 100644
index 000000000000..9acb1e729bd6
--- /dev/null
+++ b/drivers/vfio/Kconfig
@@ -0,0 +1,8 @@
1menuconfig VFIO
2 tristate "VFIO Non-Privileged userspace driver framework"
3 depends on IOMMU_API
4 help
5 VFIO provides a framework for secure userspace device drivers.
6 See Documentation/vfio.txt for more details.
7
8 If you don't know what to do here, say N.
diff --git a/drivers/vfio/Makefile b/drivers/vfio/Makefile
new file mode 100644
index 000000000000..7500a67a42a0
--- /dev/null
+++ b/drivers/vfio/Makefile
@@ -0,0 +1 @@
obj-$(CONFIG_VFIO) += vfio.o
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
new file mode 100644
index 000000000000..052e310aed72
--- /dev/null
+++ b/drivers/vfio/vfio.c
@@ -0,0 +1,1413 @@
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>
25#include <linux/module.h>
26#include <linux/mutex.h>
27#include <linux/sched.h>
28#include <linux/slab.h>
29#include <linux/string.h>
30#include <linux/uaccess.h>
31#include <linux/vfio.h>
32#include <linux/wait.h>
33
34#define DRIVER_VERSION "0.3"
35#define DRIVER_AUTHOR "Alex Williamson <alex.williamson@redhat.com>"
36#define DRIVER_DESC "VFIO - User Level meta-driver"
37
38static struct vfio {
39 struct class *class;
40 struct list_head iommu_drivers_list;
41 struct mutex iommu_drivers_lock;
42 struct list_head group_list;
43 struct idr group_idr;
44 struct mutex group_lock;
45 struct cdev group_cdev;
46 struct device *dev;
47 dev_t devt;
48 struct cdev cdev;
49 wait_queue_head_t release_q;
50} vfio;
51
52struct vfio_iommu_driver {
53 const struct vfio_iommu_driver_ops *ops;
54 struct list_head vfio_next;
55};
56
57struct vfio_container {
58 struct kref kref;
59 struct list_head group_list;
60 struct mutex group_lock;
61 struct vfio_iommu_driver *iommu_driver;
62 void *iommu_data;
63};
64
65struct vfio_group {
66 struct kref kref;
67 int minor;
68 atomic_t container_users;
69 struct iommu_group *iommu_group;
70 struct vfio_container *container;
71 struct list_head device_list;
72 struct mutex device_lock;
73 struct device *dev;
74 struct notifier_block nb;
75 struct list_head vfio_next;
76 struct list_head container_next;
77};
78
79struct vfio_device {
80 struct kref kref;
81 struct device *dev;
82 const struct vfio_device_ops *ops;
83 struct vfio_group *group;
84 struct list_head group_next;
85 void *device_data;
86};
87
88/**
89 * IOMMU driver registration
90 */
91int vfio_register_iommu_driver(const struct vfio_iommu_driver_ops *ops)
92{
93 struct vfio_iommu_driver *driver, *tmp;
94
95 driver = kzalloc(sizeof(*driver), GFP_KERNEL);
96 if (!driver)
97 return -ENOMEM;
98
99 driver->ops = ops;
100
101 mutex_lock(&vfio.iommu_drivers_lock);
102
103 /* Check for duplicates */
104 list_for_each_entry(tmp, &vfio.iommu_drivers_list, vfio_next) {
105 if (tmp->ops == ops) {
106 mutex_unlock(&vfio.iommu_drivers_lock);
107 kfree(driver);
108 return -EINVAL;
109 }
110 }
111
112 list_add(&driver->vfio_next, &vfio.iommu_drivers_list);
113
114 mutex_unlock(&vfio.iommu_drivers_lock);
115
116 return 0;
117}
118EXPORT_SYMBOL_GPL(vfio_register_iommu_driver);
119
120void vfio_unregister_iommu_driver(const struct vfio_iommu_driver_ops *ops)
121{
122 struct vfio_iommu_driver *driver;
123
124 mutex_lock(&vfio.iommu_drivers_lock);
125 list_for_each_entry(driver, &vfio.iommu_drivers_list, vfio_next) {
126 if (driver->ops == ops) {
127 list_del(&driver->vfio_next);
128 mutex_unlock(&vfio.iommu_drivers_lock);
129 kfree(driver);
130 return;
131 }
132 }
133 mutex_unlock(&vfio.iommu_drivers_lock);
134}
135EXPORT_SYMBOL_GPL(vfio_unregister_iommu_driver);
136
137/**
138 * Group minor allocation/free - both called with vfio.group_lock held
139 */
140static int vfio_alloc_group_minor(struct vfio_group *group)
141{
142 int ret, minor;
143
144again:
145 if (unlikely(idr_pre_get(&vfio.group_idr, GFP_KERNEL) == 0))
146 return -ENOMEM;
147
148 /* index 0 is used by /dev/vfio/vfio */
149 ret = idr_get_new_above(&vfio.group_idr, group, 1, &minor);
150 if (ret == -EAGAIN)
151 goto again;
152 if (ret || minor > MINORMASK) {
153 if (minor > MINORMASK)
154 idr_remove(&vfio.group_idr, minor);
155 return -ENOSPC;
156 }
157
158 return minor;
159}
160
161static void vfio_free_group_minor(int minor)
162{
163 idr_remove(&vfio.group_idr, minor);
164}
165
166static int vfio_iommu_group_notifier(struct notifier_block *nb,
167 unsigned long action, void *data);
168static void vfio_group_get(struct vfio_group *group);
169
170/**
171 * Container objects - containers are created when /dev/vfio/vfio is
172 * opened, but their lifecycle extends until the last user is done, so
173 * it's freed via kref. Must support container/group/device being
174 * closed in any order.
175 */
176static void vfio_container_get(struct vfio_container *container)
177{
178 kref_get(&container->kref);
179}
180
181static void vfio_container_release(struct kref *kref)
182{
183 struct vfio_container *container;
184 container = container_of(kref, struct vfio_container, kref);
185
186 kfree(container);
187}
188
189static void vfio_container_put(struct vfio_container *container)
190{
191 kref_put(&container->kref, vfio_container_release);
192}
193
194/**
195 * Group objects - create, release, get, put, search
196 */
197static struct vfio_group *vfio_create_group(struct iommu_group *iommu_group)
198{
199 struct vfio_group *group, *tmp;
200 struct device *dev;
201 int ret, minor;
202
203 group = kzalloc(sizeof(*group), GFP_KERNEL);
204 if (!group)
205 return ERR_PTR(-ENOMEM);
206
207 kref_init(&group->kref);
208 INIT_LIST_HEAD(&group->device_list);
209 mutex_init(&group->device_lock);
210 atomic_set(&group->container_users, 0);
211 group->iommu_group = iommu_group;
212
213 group->nb.notifier_call = vfio_iommu_group_notifier;
214
215 /*
216 * blocking notifiers acquire a rwsem around registering and hold
217 * it around callback. Therefore, need to register outside of
218 * vfio.group_lock to avoid A-B/B-A contention. Our callback won't
219 * do anything unless it can find the group in vfio.group_list, so
220 * no harm in registering early.
221 */
222 ret = iommu_group_register_notifier(iommu_group, &group->nb);
223 if (ret) {
224 kfree(group);
225 return ERR_PTR(ret);
226 }
227
228 mutex_lock(&vfio.group_lock);
229
230 minor = vfio_alloc_group_minor(group);
231 if (minor < 0) {
232 mutex_unlock(&vfio.group_lock);
233 kfree(group);
234 return ERR_PTR(minor);
235 }
236
237 /* Did we race creating this group? */
238 list_for_each_entry(tmp, &vfio.group_list, vfio_next) {
239 if (tmp->iommu_group == iommu_group) {
240 vfio_group_get(tmp);
241 vfio_free_group_minor(minor);
242 mutex_unlock(&vfio.group_lock);
243 kfree(group);
244 return tmp;
245 }
246 }
247
248 dev = device_create(vfio.class, NULL, MKDEV(MAJOR(vfio.devt), minor),
249 group, "%d", iommu_group_id(iommu_group));
250 if (IS_ERR(dev)) {
251 vfio_free_group_minor(minor);
252 mutex_unlock(&vfio.group_lock);
253 kfree(group);
254 return (struct vfio_group *)dev; /* ERR_PTR */
255 }
256
257 group->minor = minor;
258 group->dev = dev;
259
260 list_add(&group->vfio_next, &vfio.group_list);
261
262 mutex_unlock(&vfio.group_lock);
263
264 return group;
265}
266
267static void vfio_group_release(struct kref *kref)
268{
269 struct vfio_group *group = container_of(kref, struct vfio_group, kref);
270
271 WARN_ON(!list_empty(&group->device_list));
272
273 device_destroy(vfio.class, MKDEV(MAJOR(vfio.devt), group->minor));
274 list_del(&group->vfio_next);
275 vfio_free_group_minor(group->minor);
276
277 mutex_unlock(&vfio.group_lock);
278
279 /*
280 * Unregister outside of lock. A spurious callback is harmless now
281 * that the group is no longer in vfio.group_list.
282 */
283 iommu_group_unregister_notifier(group->iommu_group, &group->nb);
284
285 kfree(group);
286}
287
288static void vfio_group_put(struct vfio_group *group)
289{
290 mutex_lock(&vfio.group_lock);
291 /*
292 * Release needs to unlock to unregister the notifier, so only
293 * unlock if not released.
294 */
295 if (!kref_put(&group->kref, vfio_group_release))
296 mutex_unlock(&vfio.group_lock);
297}
298
299/* Assume group_lock or group reference is held */
300static 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 */
309static 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
326static
327struct 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
344static 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 */
363static
364struct 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;
370 int ret;
371
372 device = kzalloc(sizeof(*device), GFP_KERNEL);
373 if (!device)
374 return ERR_PTR(-ENOMEM);
375
376 kref_init(&device->kref);
377 device->dev = dev;
378 device->group = group;
379 device->ops = ops;
380 device->device_data = device_data;
381
382 ret = dev_set_drvdata(dev, device);
383 if (ret) {
384 kfree(device);
385 return ERR_PTR(ret);
386 }
387
388 /* No need to get group_lock, caller has group reference */
389 vfio_group_get(group);
390
391 mutex_lock(&group->device_lock);
392 list_add(&device->group_next, &group->device_list);
393 mutex_unlock(&group->device_lock);
394
395 return device;
396}
397
398static void vfio_device_release(struct kref *kref)
399{
400 struct vfio_device *device = container_of(kref,
401 struct vfio_device, kref);
402 struct vfio_group *group = device->group;
403
404 mutex_lock(&group->device_lock);
405 list_del(&device->group_next);
406 mutex_unlock(&group->device_lock);
407
408 dev_set_drvdata(device->dev, NULL);
409
410 kfree(device);
411
412 /* vfio_del_group_dev may be waiting for this device */
413 wake_up(&vfio.release_q);
414}
415
416/* Device reference always implies a group reference */
417static void vfio_device_put(struct vfio_device *device)
418{
419 kref_put(&device->kref, vfio_device_release);
420 vfio_group_put(device->group);
421}
422
423static void vfio_device_get(struct vfio_device *device)
424{
425 vfio_group_get(device->group);
426 kref_get(&device->kref);
427}
428
429static struct vfio_device *vfio_group_get_device(struct vfio_group *group,
430 struct device *dev)
431{
432 struct vfio_device *device;
433
434 mutex_lock(&group->device_lock);
435 list_for_each_entry(device, &group->device_list, group_next) {
436 if (device->dev == dev) {
437 vfio_device_get(device);
438 mutex_unlock(&group->device_lock);
439 return device;
440 }
441 }
442 mutex_unlock(&group->device_lock);
443 return NULL;
444}
445
446/*
447 * Whitelist some drivers that we know are safe (no dma) or just sit on
448 * a device. It's not always practical to leave a device within a group
449 * driverless as it could get re-bound to something unsafe.
450 */
451static const char * const vfio_driver_whitelist[] = { "pci-stub" };
452
453static bool vfio_whitelisted_driver(struct device_driver *drv)
454{
455 int i;
456
457 for (i = 0; i < ARRAY_SIZE(vfio_driver_whitelist); i++) {
458 if (!strcmp(drv->name, vfio_driver_whitelist[i]))
459 return true;
460 }
461
462 return false;
463}
464
465/*
466 * A vfio group is viable for use by userspace if all devices are either
467 * driver-less or bound to a vfio or whitelisted driver. We test the
468 * latter by the existence of a struct vfio_device matching the dev.
469 */
470static int vfio_dev_viable(struct device *dev, void *data)
471{
472 struct vfio_group *group = data;
473 struct vfio_device *device;
474
475 if (!dev->driver || vfio_whitelisted_driver(dev->driver))
476 return 0;
477
478 device = vfio_group_get_device(group, dev);
479 if (device) {
480 vfio_device_put(device);
481 return 0;
482 }
483
484 return -EINVAL;
485}
486
487/**
488 * Async device support
489 */
490static int vfio_group_nb_add_dev(struct vfio_group *group, struct device *dev)
491{
492 struct vfio_device *device;
493
494 /* Do we already know about it? We shouldn't */
495 device = vfio_group_get_device(group, dev);
496 if (WARN_ON_ONCE(device)) {
497 vfio_device_put(device);
498 return 0;
499 }
500
501 /* Nothing to do for idle groups */
502 if (!atomic_read(&group->container_users))
503 return 0;
504
505 /* TODO Prevent device auto probing */
506 WARN("Device %s added to live group %d!\n", dev_name(dev),
507 iommu_group_id(group->iommu_group));
508
509 return 0;
510}
511
512static int vfio_group_nb_del_dev(struct vfio_group *group, struct device *dev)
513{
514 struct vfio_device *device;
515
516 /*
517 * Expect to fall out here. If a device was in use, it would
518 * have been bound to a vfio sub-driver, which would have blocked
519 * in .remove at vfio_del_group_dev. Sanity check that we no
520 * longer track the device, so it's safe to remove.
521 */
522 device = vfio_group_get_device(group, dev);
523 if (likely(!device))
524 return 0;
525
526 WARN("Device %s removed from live group %d!\n", dev_name(dev),
527 iommu_group_id(group->iommu_group));
528
529 vfio_device_put(device);
530 return 0;
531}
532
533static int vfio_group_nb_verify(struct vfio_group *group, struct device *dev)
534{
535 /* We don't care what happens when the group isn't in use */
536 if (!atomic_read(&group->container_users))
537 return 0;
538
539 return vfio_dev_viable(dev, group);
540}
541
542static int vfio_iommu_group_notifier(struct notifier_block *nb,
543 unsigned long action, void *data)
544{
545 struct vfio_group *group = container_of(nb, struct vfio_group, nb);
546 struct device *dev = data;
547
548 /*
549 * Need to go through a group_lock lookup to get a reference or
550 * we risk racing a group being removed. Leave a WARN_ON for
551 * debuging, but if the group no longer exists, a spurious notify
552 * is harmless.
553 */
554 group = vfio_group_try_get(group);
555 if (WARN_ON(!group))
556 return NOTIFY_OK;
557
558 switch (action) {
559 case IOMMU_GROUP_NOTIFY_ADD_DEVICE:
560 vfio_group_nb_add_dev(group, dev);
561 break;
562 case IOMMU_GROUP_NOTIFY_DEL_DEVICE:
563 vfio_group_nb_del_dev(group, dev);
564 break;
565 case IOMMU_GROUP_NOTIFY_BIND_DRIVER:
566 pr_debug("%s: Device %s, group %d binding to driver\n",
567 __func__, dev_name(dev),
568 iommu_group_id(group->iommu_group));
569 break;
570 case IOMMU_GROUP_NOTIFY_BOUND_DRIVER:
571 pr_debug("%s: Device %s, group %d bound to driver %s\n",
572 __func__, dev_name(dev),
573 iommu_group_id(group->iommu_group), dev->driver->name);
574 BUG_ON(vfio_group_nb_verify(group, dev));
575 break;
576 case IOMMU_GROUP_NOTIFY_UNBIND_DRIVER:
577 pr_debug("%s: Device %s, group %d unbinding from driver %s\n",
578 __func__, dev_name(dev),
579 iommu_group_id(group->iommu_group), dev->driver->name);
580 break;
581 case IOMMU_GROUP_NOTIFY_UNBOUND_DRIVER:
582 pr_debug("%s: Device %s, group %d unbound from driver\n",
583 __func__, dev_name(dev),
584 iommu_group_id(group->iommu_group));
585 /*
586 * XXX An unbound device in a live group is ok, but we'd
587 * really like to avoid the above BUG_ON by preventing other
588 * drivers from binding to it. Once that occurs, we have to
589 * stop the system to maintain isolation. At a minimum, we'd
590 * want a toggle to disable driver auto probe for this device.
591 */
592 break;
593 }
594
595 vfio_group_put(group);
596 return NOTIFY_OK;
597}
598
599/**
600 * VFIO driver API
601 */
602int vfio_add_group_dev(struct device *dev,
603 const struct vfio_device_ops *ops, void *device_data)
604{
605 struct iommu_group *iommu_group;
606 struct vfio_group *group;
607 struct vfio_device *device;
608
609 iommu_group = iommu_group_get(dev);
610 if (!iommu_group)
611 return -EINVAL;
612
613 group = vfio_group_get_from_iommu(iommu_group);
614 if (!group) {
615 group = vfio_create_group(iommu_group);
616 if (IS_ERR(group)) {
617 iommu_group_put(iommu_group);
618 return PTR_ERR(group);
619 }
620 }
621
622 device = vfio_group_get_device(group, dev);
623 if (device) {
624 WARN(1, "Device %s already exists on group %d\n",
625 dev_name(dev), iommu_group_id(iommu_group));
626 vfio_device_put(device);
627 vfio_group_put(group);
628 iommu_group_put(iommu_group);
629 return -EBUSY;
630 }
631
632 device = vfio_group_create_device(group, dev, ops, device_data);
633 if (IS_ERR(device)) {
634 vfio_group_put(group);
635 iommu_group_put(iommu_group);
636 return PTR_ERR(device);
637 }
638
639 /*
640 * Added device holds reference to iommu_group and vfio_device
641 * (which in turn holds reference to vfio_group). Drop extra
642 * group reference used while acquiring device.
643 */
644 vfio_group_put(group);
645
646 return 0;
647}
648EXPORT_SYMBOL_GPL(vfio_add_group_dev);
649
650/* Test whether a struct device is present in our tracking */
651static bool vfio_dev_present(struct device *dev)
652{
653 struct iommu_group *iommu_group;
654 struct vfio_group *group;
655 struct vfio_device *device;
656
657 iommu_group = iommu_group_get(dev);
658 if (!iommu_group)
659 return false;
660
661 group = vfio_group_get_from_iommu(iommu_group);
662 if (!group) {
663 iommu_group_put(iommu_group);
664 return false;
665 }
666
667 device = vfio_group_get_device(group, dev);
668 if (!device) {
669 vfio_group_put(group);
670 iommu_group_put(iommu_group);
671 return false;
672 }
673
674 vfio_device_put(device);
675 vfio_group_put(group);
676 iommu_group_put(iommu_group);
677 return true;
678}
679
680/*
681 * Decrement the device reference count and wait for the device to be
682 * removed. Open file descriptors for the device... */
683void *vfio_del_group_dev(struct device *dev)
684{
685 struct vfio_device *device = dev_get_drvdata(dev);
686 struct vfio_group *group = device->group;
687 struct iommu_group *iommu_group = group->iommu_group;
688 void *device_data = device->device_data;
689
690 vfio_device_put(device);
691
692 /* TODO send a signal to encourage this to be released */
693 wait_event(vfio.release_q, !vfio_dev_present(dev));
694
695 iommu_group_put(iommu_group);
696
697 return device_data;
698}
699EXPORT_SYMBOL_GPL(vfio_del_group_dev);
700
701/**
702 * VFIO base fd, /dev/vfio/vfio
703 */
704static long vfio_ioctl_check_extension(struct vfio_container *container,
705 unsigned long arg)
706{
707 struct vfio_iommu_driver *driver = container->iommu_driver;
708 long ret = 0;
709
710 switch (arg) {
711 /* No base extensions yet */
712 default:
713 /*
714 * If no driver is set, poll all registered drivers for
715 * extensions and return the first positive result. If
716 * a driver is already set, further queries will be passed
717 * only to that driver.
718 */
719 if (!driver) {
720 mutex_lock(&vfio.iommu_drivers_lock);
721 list_for_each_entry(driver, &vfio.iommu_drivers_list,
722 vfio_next) {
723 if (!try_module_get(driver->ops->owner))
724 continue;
725
726 ret = driver->ops->ioctl(NULL,
727 VFIO_CHECK_EXTENSION,
728 arg);
729 module_put(driver->ops->owner);
730 if (ret > 0)
731 break;
732 }
733 mutex_unlock(&vfio.iommu_drivers_lock);
734 } else
735 ret = driver->ops->ioctl(container->iommu_data,
736 VFIO_CHECK_EXTENSION, arg);
737 }
738
739 return ret;
740}
741
742/* hold container->group_lock */
743static int __vfio_container_attach_groups(struct vfio_container *container,
744 struct vfio_iommu_driver *driver,
745 void *data)
746{
747 struct vfio_group *group;
748 int ret = -ENODEV;
749
750 list_for_each_entry(group, &container->group_list, container_next) {
751 ret = driver->ops->attach_group(data, group->iommu_group);
752 if (ret)
753 goto unwind;
754 }
755
756 return ret;
757
758unwind:
759 list_for_each_entry_continue_reverse(group, &container->group_list,
760 container_next) {
761 driver->ops->detach_group(data, group->iommu_group);
762 }
763
764 return ret;
765}
766
767static long vfio_ioctl_set_iommu(struct vfio_container *container,
768 unsigned long arg)
769{
770 struct vfio_iommu_driver *driver;
771 long ret = -ENODEV;
772
773 mutex_lock(&container->group_lock);
774
775 /*
776 * The container is designed to be an unprivileged interface while
777 * the group can be assigned to specific users. Therefore, only by
778 * adding a group to a container does the user get the privilege of
779 * enabling the iommu, which may allocate finite resources. There
780 * is no unset_iommu, but by removing all the groups from a container,
781 * the container is deprivileged and returns to an unset state.
782 */
783 if (list_empty(&container->group_list) || container->iommu_driver) {
784 mutex_unlock(&container->group_lock);
785 return -EINVAL;
786 }
787
788 mutex_lock(&vfio.iommu_drivers_lock);
789 list_for_each_entry(driver, &vfio.iommu_drivers_list, vfio_next) {
790 void *data;
791
792 if (!try_module_get(driver->ops->owner))
793 continue;
794
795 /*
796 * The arg magic for SET_IOMMU is the same as CHECK_EXTENSION,
797 * so test which iommu driver reported support for this
798 * extension and call open on them. We also pass them the
799 * magic, allowing a single driver to support multiple
800 * interfaces if they'd like.
801 */
802 if (driver->ops->ioctl(NULL, VFIO_CHECK_EXTENSION, arg) <= 0) {
803 module_put(driver->ops->owner);
804 continue;
805 }
806
807 /* module reference holds the driver we're working on */
808 mutex_unlock(&vfio.iommu_drivers_lock);
809
810 data = driver->ops->open(arg);
811 if (IS_ERR(data)) {
812 ret = PTR_ERR(data);
813 module_put(driver->ops->owner);
814 goto skip_drivers_unlock;
815 }
816
817 ret = __vfio_container_attach_groups(container, driver, data);
818 if (!ret) {
819 container->iommu_driver = driver;
820 container->iommu_data = data;
821 } else {
822 driver->ops->release(data);
823 module_put(driver->ops->owner);
824 }
825
826 goto skip_drivers_unlock;
827 }
828
829 mutex_unlock(&vfio.iommu_drivers_lock);
830skip_drivers_unlock:
831 mutex_unlock(&container->group_lock);
832
833 return ret;
834}
835
836static long vfio_fops_unl_ioctl(struct file *filep,
837 unsigned int cmd, unsigned long arg)
838{
839 struct vfio_container *container = filep->private_data;
840 struct vfio_iommu_driver *driver;
841 void *data;
842 long ret = -EINVAL;
843
844 if (!container)
845 return ret;
846
847 driver = container->iommu_driver;
848 data = container->iommu_data;
849
850 switch (cmd) {
851 case VFIO_GET_API_VERSION:
852 ret = VFIO_API_VERSION;
853 break;
854 case VFIO_CHECK_EXTENSION:
855 ret = vfio_ioctl_check_extension(container, arg);
856 break;
857 case VFIO_SET_IOMMU:
858 ret = vfio_ioctl_set_iommu(container, arg);
859 break;
860 default:
861 if (driver) /* passthrough all unrecognized ioctls */
862 ret = driver->ops->ioctl(data, cmd, arg);
863 }
864
865 return ret;
866}
867
868#ifdef CONFIG_COMPAT
869static long vfio_fops_compat_ioctl(struct file *filep,
870 unsigned int cmd, unsigned long arg)
871{
872 arg = (unsigned long)compat_ptr(arg);
873 return vfio_fops_unl_ioctl(filep, cmd, arg);
874}
875#endif /* CONFIG_COMPAT */
876
877static int vfio_fops_open(struct inode *inode, struct file *filep)
878{
879 struct vfio_container *container;
880
881 container = kzalloc(sizeof(*container), GFP_KERNEL);
882 if (!container)
883 return -ENOMEM;
884
885 INIT_LIST_HEAD(&container->group_list);
886 mutex_init(&container->group_lock);
887 kref_init(&container->kref);
888
889 filep->private_data = container;
890
891 return 0;
892}
893
894static int vfio_fops_release(struct inode *inode, struct file *filep)
895{
896 struct vfio_container *container = filep->private_data;
897
898 filep->private_data = NULL;
899
900 vfio_container_put(container);
901
902 return 0;
903}
904
905/*
906 * Once an iommu driver is set, we optionally pass read/write/mmap
907 * on to the driver, allowing management interfaces beyond ioctl.
908 */
909static ssize_t vfio_fops_read(struct file *filep, char __user *buf,
910 size_t count, loff_t *ppos)
911{
912 struct vfio_container *container = filep->private_data;
913 struct vfio_iommu_driver *driver = container->iommu_driver;
914
915 if (unlikely(!driver || !driver->ops->read))
916 return -EINVAL;
917
918 return driver->ops->read(container->iommu_data, buf, count, ppos);
919}
920
921static ssize_t vfio_fops_write(struct file *filep, const char __user *buf,
922 size_t count, loff_t *ppos)
923{
924 struct vfio_container *container = filep->private_data;
925 struct vfio_iommu_driver *driver = container->iommu_driver;
926
927 if (unlikely(!driver || !driver->ops->write))
928 return -EINVAL;
929
930 return driver->ops->write(container->iommu_data, buf, count, ppos);
931}
932
933static int vfio_fops_mmap(struct file *filep, struct vm_area_struct *vma)
934{
935 struct vfio_container *container = filep->private_data;
936 struct vfio_iommu_driver *driver = container->iommu_driver;
937
938 if (unlikely(!driver || !driver->ops->mmap))
939 return -EINVAL;
940
941 return driver->ops->mmap(container->iommu_data, vma);
942}
943
944static const struct file_operations vfio_fops = {
945 .owner = THIS_MODULE,
946 .open = vfio_fops_open,
947 .release = vfio_fops_release,
948 .read = vfio_fops_read,
949 .write = vfio_fops_write,
950 .unlocked_ioctl = vfio_fops_unl_ioctl,
951#ifdef CONFIG_COMPAT
952 .compat_ioctl = vfio_fops_compat_ioctl,
953#endif
954 .mmap = vfio_fops_mmap,
955};
956
957/**
958 * VFIO Group fd, /dev/vfio/$GROUP
959 */
960static void __vfio_group_unset_container(struct vfio_group *group)
961{
962 struct vfio_container *container = group->container;
963 struct vfio_iommu_driver *driver;
964
965 mutex_lock(&container->group_lock);
966
967 driver = container->iommu_driver;
968 if (driver)
969 driver->ops->detach_group(container->iommu_data,
970 group->iommu_group);
971
972 group->container = NULL;
973 list_del(&group->container_next);
974
975 /* Detaching the last group deprivileges a container, remove iommu */
976 if (driver && list_empty(&container->group_list)) {
977 driver->ops->release(container->iommu_data);
978 module_put(driver->ops->owner);
979 container->iommu_driver = NULL;
980 container->iommu_data = NULL;
981 }
982
983 mutex_unlock(&container->group_lock);
984
985 vfio_container_put(container);
986}
987
988/*
989 * VFIO_GROUP_UNSET_CONTAINER should fail if there are other users or
990 * if there was no container to unset. Since the ioctl is called on
991 * the group, we know that still exists, therefore the only valid
992 * transition here is 1->0.
993 */
994static int vfio_group_unset_container(struct vfio_group *group)
995{
996 int users = atomic_cmpxchg(&group->container_users, 1, 0);
997
998 if (!users)
999 return -EINVAL;
1000 if (users != 1)
1001 return -EBUSY;
1002
1003 __vfio_group_unset_container(group);
1004
1005 return 0;
1006}
1007
1008/*
1009 * When removing container users, anything that removes the last user
1010 * implicitly removes the group from the container. That is, if the
1011 * group file descriptor is closed, as well as any device file descriptors,
1012 * the group is free.
1013 */
1014static void vfio_group_try_dissolve_container(struct vfio_group *group)
1015{
1016 if (0 == atomic_dec_if_positive(&group->container_users))
1017 __vfio_group_unset_container(group);
1018}
1019
1020static int vfio_group_set_container(struct vfio_group *group, int container_fd)
1021{
1022 struct file *filep;
1023 struct vfio_container *container;
1024 struct vfio_iommu_driver *driver;
1025 int ret = 0;
1026
1027 if (atomic_read(&group->container_users))
1028 return -EINVAL;
1029
1030 filep = fget(container_fd);
1031 if (!filep)
1032 return -EBADF;
1033
1034 /* Sanity check, is this really our fd? */
1035 if (filep->f_op != &vfio_fops) {
1036 fput(filep);
1037 return -EINVAL;
1038 }
1039
1040 container = filep->private_data;
1041 WARN_ON(!container); /* fget ensures we don't race vfio_release */
1042
1043 mutex_lock(&container->group_lock);
1044
1045 driver = container->iommu_driver;
1046 if (driver) {
1047 ret = driver->ops->attach_group(container->iommu_data,
1048 group->iommu_group);
1049 if (ret)
1050 goto unlock_out;
1051 }
1052
1053 group->container = container;
1054 list_add(&group->container_next, &container->group_list);
1055
1056 /* Get a reference on the container and mark a user within the group */
1057 vfio_container_get(container);
1058 atomic_inc(&group->container_users);
1059
1060unlock_out:
1061 mutex_unlock(&container->group_lock);
1062 fput(filep);
1063
1064 return ret;
1065}
1066
1067static bool vfio_group_viable(struct vfio_group *group)
1068{
1069 return (iommu_group_for_each_dev(group->iommu_group,
1070 group, vfio_dev_viable) == 0);
1071}
1072
1073static const struct file_operations vfio_device_fops;
1074
1075static int vfio_group_get_device_fd(struct vfio_group *group, char *buf)
1076{
1077 struct vfio_device *device;
1078 struct file *filep;
1079 int ret = -ENODEV;
1080
1081 if (0 == atomic_read(&group->container_users) ||
1082 !group->container->iommu_driver || !vfio_group_viable(group))
1083 return -EINVAL;
1084
1085 mutex_lock(&group->device_lock);
1086 list_for_each_entry(device, &group->device_list, group_next) {
1087 if (strcmp(dev_name(device->dev), buf))
1088 continue;
1089
1090 ret = device->ops->open(device->device_data);
1091 if (ret)
1092 break;
1093 /*
1094 * We can't use anon_inode_getfd() because we need to modify
1095 * the f_mode flags directly to allow more than just ioctls
1096 */
1097 ret = get_unused_fd();
1098 if (ret < 0) {
1099 device->ops->release(device->device_data);
1100 break;
1101 }
1102
1103 filep = anon_inode_getfile("[vfio-device]", &vfio_device_fops,
1104 device, O_RDWR);
1105 if (IS_ERR(filep)) {
1106 put_unused_fd(ret);
1107 ret = PTR_ERR(filep);
1108 device->ops->release(device->device_data);
1109 break;
1110 }
1111
1112 /*
1113 * TODO: add an anon_inode interface to do this.
1114 * Appears to be missing by lack of need rather than
1115 * explicitly prevented. Now there's need.
1116 */
1117 filep->f_mode |= (FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE);
1118
1119 fd_install(ret, filep);
1120
1121 vfio_device_get(device);
1122 atomic_inc(&group->container_users);
1123 break;
1124 }
1125 mutex_unlock(&group->device_lock);
1126
1127 return ret;
1128}
1129
1130static long vfio_group_fops_unl_ioctl(struct file *filep,
1131 unsigned int cmd, unsigned long arg)
1132{
1133 struct vfio_group *group = filep->private_data;
1134 long ret = -ENOTTY;
1135
1136 switch (cmd) {
1137 case VFIO_GROUP_GET_STATUS:
1138 {
1139 struct vfio_group_status status;
1140 unsigned long minsz;
1141
1142 minsz = offsetofend(struct vfio_group_status, flags);
1143
1144 if (copy_from_user(&status, (void __user *)arg, minsz))
1145 return -EFAULT;
1146
1147 if (status.argsz < minsz)
1148 return -EINVAL;
1149
1150 status.flags = 0;
1151
1152 if (vfio_group_viable(group))
1153 status.flags |= VFIO_GROUP_FLAGS_VIABLE;
1154
1155 if (group->container)
1156 status.flags |= VFIO_GROUP_FLAGS_CONTAINER_SET;
1157
1158 if (copy_to_user((void __user *)arg, &status, minsz))
1159 return -EFAULT;
1160
1161 ret = 0;
1162 break;
1163 }
1164 case VFIO_GROUP_SET_CONTAINER:
1165 {
1166 int fd;
1167
1168 if (get_user(fd, (int __user *)arg))
1169 return -EFAULT;
1170
1171 if (fd < 0)
1172 return -EINVAL;
1173
1174 ret = vfio_group_set_container(group, fd);
1175 break;
1176 }
1177 case VFIO_GROUP_UNSET_CONTAINER:
1178 ret = vfio_group_unset_container(group);
1179 break;
1180 case VFIO_GROUP_GET_DEVICE_FD:
1181 {
1182 char *buf;
1183
1184 buf = strndup_user((const char __user *)arg, PAGE_SIZE);
1185 if (IS_ERR(buf))
1186 return PTR_ERR(buf);
1187
1188 ret = vfio_group_get_device_fd(group, buf);
1189 kfree(buf);
1190 break;
1191 }
1192 }
1193
1194 return ret;
1195}
1196
1197#ifdef CONFIG_COMPAT
1198static long vfio_group_fops_compat_ioctl(struct file *filep,
1199 unsigned int cmd, unsigned long arg)
1200{
1201 arg = (unsigned long)compat_ptr(arg);
1202 return vfio_group_fops_unl_ioctl(filep, cmd, arg);
1203}
1204#endif /* CONFIG_COMPAT */
1205
1206static int vfio_group_fops_open(struct inode *inode, struct file *filep)
1207{
1208 struct vfio_group *group;
1209
1210 group = vfio_group_get_from_minor(iminor(inode));
1211 if (!group)
1212 return -ENODEV;
1213
1214 if (group->container) {
1215 vfio_group_put(group);
1216 return -EBUSY;
1217 }
1218
1219 filep->private_data = group;
1220
1221 return 0;
1222}
1223
1224static int vfio_group_fops_release(struct inode *inode, struct file *filep)
1225{
1226 struct vfio_group *group = filep->private_data;
1227
1228 filep->private_data = NULL;
1229
1230 vfio_group_try_dissolve_container(group);
1231
1232 vfio_group_put(group);
1233
1234 return 0;
1235}
1236
1237static const struct file_operations vfio_group_fops = {
1238 .owner = THIS_MODULE,
1239 .unlocked_ioctl = vfio_group_fops_unl_ioctl,
1240#ifdef CONFIG_COMPAT
1241 .compat_ioctl = vfio_group_fops_compat_ioctl,
1242#endif
1243 .open = vfio_group_fops_open,
1244 .release = vfio_group_fops_release,
1245};
1246
1247/**
1248 * VFIO Device fd
1249 */
1250static int vfio_device_fops_release(struct inode *inode, struct file *filep)
1251{
1252 struct vfio_device *device = filep->private_data;
1253
1254 device->ops->release(device->device_data);
1255
1256 vfio_group_try_dissolve_container(device->group);
1257
1258 vfio_device_put(device);
1259
1260 return 0;
1261}
1262
1263static long vfio_device_fops_unl_ioctl(struct file *filep,
1264 unsigned int cmd, unsigned long arg)
1265{
1266 struct vfio_device *device = filep->private_data;
1267
1268 if (unlikely(!device->ops->ioctl))
1269 return -EINVAL;
1270
1271 return device->ops->ioctl(device->device_data, cmd, arg);
1272}
1273
1274static ssize_t vfio_device_fops_read(struct file *filep, char __user *buf,
1275 size_t count, loff_t *ppos)
1276{
1277 struct vfio_device *device = filep->private_data;
1278
1279 if (unlikely(!device->ops->read))
1280 return -EINVAL;
1281
1282 return device->ops->read(device->device_data, buf, count, ppos);
1283}
1284
1285static ssize_t vfio_device_fops_write(struct file *filep,
1286 const char __user *buf,
1287 size_t count, loff_t *ppos)
1288{
1289 struct vfio_device *device = filep->private_data;
1290
1291 if (unlikely(!device->ops->write))
1292 return -EINVAL;
1293
1294 return device->ops->write(device->device_data, buf, count, ppos);
1295}
1296
1297static int vfio_device_fops_mmap(struct file *filep, struct vm_area_struct *vma)
1298{
1299 struct vfio_device *device = filep->private_data;
1300
1301 if (unlikely(!device->ops->mmap))
1302 return -EINVAL;
1303
1304 return device->ops->mmap(device->device_data, vma);
1305}
1306
1307#ifdef CONFIG_COMPAT
1308static long vfio_device_fops_compat_ioctl(struct file *filep,
1309 unsigned int cmd, unsigned long arg)
1310{
1311 arg = (unsigned long)compat_ptr(arg);
1312 return vfio_device_fops_unl_ioctl(filep, cmd, arg);
1313}
1314#endif /* CONFIG_COMPAT */
1315
1316static const struct file_operations vfio_device_fops = {
1317 .owner = THIS_MODULE,
1318 .release = vfio_device_fops_release,
1319 .read = vfio_device_fops_read,
1320 .write = vfio_device_fops_write,
1321 .unlocked_ioctl = vfio_device_fops_unl_ioctl,
1322#ifdef CONFIG_COMPAT
1323 .compat_ioctl = vfio_device_fops_compat_ioctl,
1324#endif
1325 .mmap = vfio_device_fops_mmap,
1326};
1327
1328/**
1329 * Module/class support
1330 */
1331static char *vfio_devnode(struct device *dev, umode_t *mode)
1332{
1333 return kasprintf(GFP_KERNEL, "vfio/%s", dev_name(dev));
1334}
1335
1336static int __init vfio_init(void)
1337{
1338 int ret;
1339
1340 idr_init(&vfio.group_idr);
1341 mutex_init(&vfio.group_lock);
1342 mutex_init(&vfio.iommu_drivers_lock);
1343 INIT_LIST_HEAD(&vfio.group_list);
1344 INIT_LIST_HEAD(&vfio.iommu_drivers_list);
1345 init_waitqueue_head(&vfio.release_q);
1346
1347 vfio.class = class_create(THIS_MODULE, "vfio");
1348 if (IS_ERR(vfio.class)) {
1349 ret = PTR_ERR(vfio.class);
1350 goto err_class;
1351 }
1352
1353 vfio.class->devnode = vfio_devnode;
1354
1355 ret = alloc_chrdev_region(&vfio.devt, 0, MINORMASK, "vfio");
1356 if (ret)
1357 goto err_base_chrdev;
1358
1359 cdev_init(&vfio.cdev, &vfio_fops);
1360 ret = cdev_add(&vfio.cdev, vfio.devt, 1);
1361 if (ret)
1362 goto err_base_cdev;
1363
1364 vfio.dev = device_create(vfio.class, NULL, vfio.devt, NULL, "vfio");
1365 if (IS_ERR(vfio.dev)) {
1366 ret = PTR_ERR(vfio.dev);
1367 goto err_base_dev;
1368 }
1369
1370 /* /dev/vfio/$GROUP */
1371 cdev_init(&vfio.group_cdev, &vfio_group_fops);
1372 ret = cdev_add(&vfio.group_cdev,
1373 MKDEV(MAJOR(vfio.devt), 1), MINORMASK - 1);
1374 if (ret)
1375 goto err_groups_cdev;
1376
1377 pr_info(DRIVER_DESC " version: " DRIVER_VERSION "\n");
1378
1379 return 0;
1380
1381err_groups_cdev:
1382 device_destroy(vfio.class, vfio.devt);
1383err_base_dev:
1384 cdev_del(&vfio.cdev);
1385err_base_cdev:
1386 unregister_chrdev_region(vfio.devt, MINORMASK);
1387err_base_chrdev:
1388 class_destroy(vfio.class);
1389 vfio.class = NULL;
1390err_class:
1391 return ret;
1392}
1393
1394static void __exit vfio_cleanup(void)
1395{
1396 WARN_ON(!list_empty(&vfio.group_list));
1397
1398 idr_destroy(&vfio.group_idr);
1399 cdev_del(&vfio.group_cdev);
1400 device_destroy(vfio.class, vfio.devt);
1401 cdev_del(&vfio.cdev);
1402 unregister_chrdev_region(vfio.devt, MINORMASK);
1403 class_destroy(vfio.class);
1404 vfio.class = NULL;
1405}
1406
1407module_init(vfio_init);
1408module_exit(vfio_cleanup);
1409
1410MODULE_VERSION(DRIVER_VERSION);
1411MODULE_LICENSE("GPL v2");
1412MODULE_AUTHOR(DRIVER_AUTHOR);
1413MODULE_DESCRIPTION(DRIVER_DESC);
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-11 07:28:46 -0500