4 * Copyright (C) 2012 Red Hat, Inc. All rights reserved.
5 * Author: Alex Williamson <alex.williamson@redhat.com>
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.
11 * Derived from original vfio:
12 * Copyright 2010 Cisco Systems, Inc. All rights reserved.
13 * Author: Tom Lyon, pugs@cisco.com
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>
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>
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"
40 struct list_head iommu_drivers_list;
41 struct mutex iommu_drivers_lock;
42 struct list_head group_list;
44 struct mutex group_lock;
45 struct cdev group_cdev;
49 wait_queue_head_t release_q;
52 struct vfio_iommu_driver {
53 const struct vfio_iommu_driver_ops *ops;
54 struct list_head vfio_next;
57 struct vfio_container {
59 struct list_head group_list;
60 struct mutex group_lock;
61 struct vfio_iommu_driver *iommu_driver;
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;
74 struct notifier_block nb;
75 struct list_head vfio_next;
76 struct list_head container_next;
82 const struct vfio_device_ops *ops;
83 struct vfio_group *group;
84 struct list_head group_next;
89 * IOMMU driver registration
91 int vfio_register_iommu_driver(const struct vfio_iommu_driver_ops *ops)
93 struct vfio_iommu_driver *driver, *tmp;
95 driver = kzalloc(sizeof(*driver), GFP_KERNEL);
101 mutex_lock(&vfio.iommu_drivers_lock);
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);
112 list_add(&driver->vfio_next, &vfio.iommu_drivers_list);
114 mutex_unlock(&vfio.iommu_drivers_lock);
118 EXPORT_SYMBOL_GPL(vfio_register_iommu_driver);
120 void vfio_unregister_iommu_driver(const struct vfio_iommu_driver_ops *ops)
122 struct vfio_iommu_driver *driver;
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);
133 mutex_unlock(&vfio.iommu_drivers_lock);
135 EXPORT_SYMBOL_GPL(vfio_unregister_iommu_driver);
138 * Group minor allocation/free - both called with vfio.group_lock held
140 static int vfio_alloc_group_minor(struct vfio_group *group)
145 if (unlikely(idr_pre_get(&vfio.group_idr, GFP_KERNEL) == 0))
148 /* index 0 is used by /dev/vfio/vfio */
149 ret = idr_get_new_above(&vfio.group_idr, group, 1, &minor);
152 if (ret || minor > MINORMASK) {
153 if (minor > MINORMASK)
154 idr_remove(&vfio.group_idr, minor);
161 static void vfio_free_group_minor(int minor)
163 idr_remove(&vfio.group_idr, minor);
166 static int vfio_iommu_group_notifier(struct notifier_block *nb,
167 unsigned long action, void *data);
168 static void vfio_group_get(struct vfio_group *group);
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.
176 static void vfio_container_get(struct vfio_container *container)
178 kref_get(&container->kref);
181 static void vfio_container_release(struct kref *kref)
183 struct vfio_container *container;
184 container = container_of(kref, struct vfio_container, kref);
189 static void vfio_container_put(struct vfio_container *container)
191 kref_put(&container->kref, vfio_container_release);
195 * Group objects - create, release, get, put, search
197 static struct vfio_group *vfio_create_group(struct iommu_group *iommu_group)
199 struct vfio_group *group, *tmp;
203 group = kzalloc(sizeof(*group), GFP_KERNEL);
205 return ERR_PTR(-ENOMEM);
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;
213 group->nb.notifier_call = vfio_iommu_group_notifier;
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.
222 ret = iommu_group_register_notifier(iommu_group, &group->nb);
228 mutex_lock(&vfio.group_lock);
230 minor = vfio_alloc_group_minor(group);
232 mutex_unlock(&vfio.group_lock);
234 return ERR_PTR(minor);
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) {
241 vfio_free_group_minor(minor);
242 mutex_unlock(&vfio.group_lock);
248 dev = device_create(vfio.class, NULL, MKDEV(MAJOR(vfio.devt), minor),
249 group, "%d", iommu_group_id(iommu_group));
251 vfio_free_group_minor(minor);
252 mutex_unlock(&vfio.group_lock);
254 return (struct vfio_group *)dev; /* ERR_PTR */
257 group->minor = minor;
260 list_add(&group->vfio_next, &vfio.group_list);
262 mutex_unlock(&vfio.group_lock);
267 static void vfio_group_release(struct kref *kref)
269 struct vfio_group *group = container_of(kref, struct vfio_group, kref);
271 WARN_ON(!list_empty(&group->device_list));
273 device_destroy(vfio.class, MKDEV(MAJOR(vfio.devt), group->minor));
274 list_del(&group->vfio_next);
275 vfio_free_group_minor(group->minor);
277 mutex_unlock(&vfio.group_lock);
280 * Unregister outside of lock. A spurious callback is harmless now
281 * that the group is no longer in vfio.group_list.
283 iommu_group_unregister_notifier(group->iommu_group, &group->nb);
288 static void vfio_group_put(struct vfio_group *group)
290 mutex_lock(&vfio.group_lock);
292 * Release needs to unlock to unregister the notifier, so only
293 * unlock if not released.
295 if (!kref_put(&group->kref, vfio_group_release))
296 mutex_unlock(&vfio.group_lock);
299 /* Assume group_lock or group reference is held */
300 static void vfio_group_get(struct vfio_group *group)
302 kref_get(&group->kref);
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.
309 static struct vfio_group *vfio_group_try_get(struct vfio_group *group)
311 struct vfio_group *target = group;
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);
321 mutex_unlock(&vfio.group_lock);
327 struct vfio_group *vfio_group_get_from_iommu(struct iommu_group *iommu_group)
329 struct vfio_group *group;
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);
339 mutex_unlock(&vfio.group_lock);
344 static struct vfio_group *vfio_group_get_from_minor(int minor)
346 struct vfio_group *group;
348 mutex_lock(&vfio.group_lock);
349 group = idr_find(&vfio.group_idr, minor);
351 mutex_unlock(&vfio.group_lock);
354 vfio_group_get(group);
355 mutex_unlock(&vfio.group_lock);
361 * Device objects - create, release, get, put, search
364 struct vfio_device *vfio_group_create_device(struct vfio_group *group,
366 const struct vfio_device_ops *ops,
369 struct vfio_device *device;
372 device = kzalloc(sizeof(*device), GFP_KERNEL);
374 return ERR_PTR(-ENOMEM);
376 kref_init(&device->kref);
378 device->group = group;
380 device->device_data = device_data;
382 ret = dev_set_drvdata(dev, device);
388 /* No need to get group_lock, caller has group reference */
389 vfio_group_get(group);
391 mutex_lock(&group->device_lock);
392 list_add(&device->group_next, &group->device_list);
393 mutex_unlock(&group->device_lock);
398 static void vfio_device_release(struct kref *kref)
400 struct vfio_device *device = container_of(kref,
401 struct vfio_device, kref);
402 struct vfio_group *group = device->group;
404 mutex_lock(&group->device_lock);
405 list_del(&device->group_next);
406 mutex_unlock(&group->device_lock);
408 dev_set_drvdata(device->dev, NULL);
412 /* vfio_del_group_dev may be waiting for this device */
413 wake_up(&vfio.release_q);
416 /* Device reference always implies a group reference */
417 static void vfio_device_put(struct vfio_device *device)
419 kref_put(&device->kref, vfio_device_release);
420 vfio_group_put(device->group);
423 static void vfio_device_get(struct vfio_device *device)
425 vfio_group_get(device->group);
426 kref_get(&device->kref);
429 static struct vfio_device *vfio_group_get_device(struct vfio_group *group,
432 struct vfio_device *device;
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);
442 mutex_unlock(&group->device_lock);
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.
451 static const char * const vfio_driver_whitelist[] = { "pci-stub" };
453 static bool vfio_whitelisted_driver(struct device_driver *drv)
457 for (i = 0; i < ARRAY_SIZE(vfio_driver_whitelist); i++) {
458 if (!strcmp(drv->name, vfio_driver_whitelist[i]))
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.
470 static int vfio_dev_viable(struct device *dev, void *data)
472 struct vfio_group *group = data;
473 struct vfio_device *device;
475 if (!dev->driver || vfio_whitelisted_driver(dev->driver))
478 device = vfio_group_get_device(group, dev);
480 vfio_device_put(device);
488 * Async device support
490 static int vfio_group_nb_add_dev(struct vfio_group *group, struct device *dev)
492 struct vfio_device *device;
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);
501 /* Nothing to do for idle groups */
502 if (!atomic_read(&group->container_users))
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));
512 static int vfio_group_nb_del_dev(struct vfio_group *group, struct device *dev)
514 struct vfio_device *device;
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.
522 device = vfio_group_get_device(group, dev);
526 WARN("Device %s removed from live group %d!\n", dev_name(dev),
527 iommu_group_id(group->iommu_group));
529 vfio_device_put(device);
533 static int vfio_group_nb_verify(struct vfio_group *group, struct device *dev)
535 /* We don't care what happens when the group isn't in use */
536 if (!atomic_read(&group->container_users))
539 return vfio_dev_viable(dev, group);
542 static int vfio_iommu_group_notifier(struct notifier_block *nb,
543 unsigned long action, void *data)
545 struct vfio_group *group = container_of(nb, struct vfio_group, nb);
546 struct device *dev = data;
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
554 group = vfio_group_try_get(group);
559 case IOMMU_GROUP_NOTIFY_ADD_DEVICE:
560 vfio_group_nb_add_dev(group, dev);
562 case IOMMU_GROUP_NOTIFY_DEL_DEVICE:
563 vfio_group_nb_del_dev(group, dev);
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));
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));
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);
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));
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.
595 vfio_group_put(group);
602 int vfio_add_group_dev(struct device *dev,
603 const struct vfio_device_ops *ops, void *device_data)
605 struct iommu_group *iommu_group;
606 struct vfio_group *group;
607 struct vfio_device *device;
609 iommu_group = iommu_group_get(dev);
613 group = vfio_group_get_from_iommu(iommu_group);
615 group = vfio_create_group(iommu_group);
617 iommu_group_put(iommu_group);
618 return PTR_ERR(group);
622 device = vfio_group_get_device(group, dev);
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);
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);
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.
644 vfio_group_put(group);
648 EXPORT_SYMBOL_GPL(vfio_add_group_dev);
650 /* Test whether a struct device is present in our tracking */
651 static bool vfio_dev_present(struct device *dev)
653 struct iommu_group *iommu_group;
654 struct vfio_group *group;
655 struct vfio_device *device;
657 iommu_group = iommu_group_get(dev);
661 group = vfio_group_get_from_iommu(iommu_group);
663 iommu_group_put(iommu_group);
667 device = vfio_group_get_device(group, dev);
669 vfio_group_put(group);
670 iommu_group_put(iommu_group);
674 vfio_device_put(device);
675 vfio_group_put(group);
676 iommu_group_put(iommu_group);
681 * Decrement the device reference count and wait for the device to be
682 * removed. Open file descriptors for the device... */
683 void *vfio_del_group_dev(struct device *dev)
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;
690 vfio_device_put(device);
692 /* TODO send a signal to encourage this to be released */
693 wait_event(vfio.release_q, !vfio_dev_present(dev));
695 iommu_group_put(iommu_group);
699 EXPORT_SYMBOL_GPL(vfio_del_group_dev);
702 * VFIO base fd, /dev/vfio/vfio
704 static long vfio_ioctl_check_extension(struct vfio_container *container,
707 struct vfio_iommu_driver *driver = container->iommu_driver;
711 /* No base extensions yet */
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.
720 mutex_lock(&vfio.iommu_drivers_lock);
721 list_for_each_entry(driver, &vfio.iommu_drivers_list,
723 if (!try_module_get(driver->ops->owner))
726 ret = driver->ops->ioctl(NULL,
727 VFIO_CHECK_EXTENSION,
729 module_put(driver->ops->owner);
733 mutex_unlock(&vfio.iommu_drivers_lock);
735 ret = driver->ops->ioctl(container->iommu_data,
736 VFIO_CHECK_EXTENSION, arg);
742 /* hold container->group_lock */
743 static int __vfio_container_attach_groups(struct vfio_container *container,
744 struct vfio_iommu_driver *driver,
747 struct vfio_group *group;
750 list_for_each_entry(group, &container->group_list, container_next) {
751 ret = driver->ops->attach_group(data, group->iommu_group);
759 list_for_each_entry_continue_reverse(group, &container->group_list,
761 driver->ops->detach_group(data, group->iommu_group);
767 static long vfio_ioctl_set_iommu(struct vfio_container *container,
770 struct vfio_iommu_driver *driver;
773 mutex_lock(&container->group_lock);
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.
783 if (list_empty(&container->group_list) || container->iommu_driver) {
784 mutex_unlock(&container->group_lock);
788 mutex_lock(&vfio.iommu_drivers_lock);
789 list_for_each_entry(driver, &vfio.iommu_drivers_list, vfio_next) {
792 if (!try_module_get(driver->ops->owner))
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.
802 if (driver->ops->ioctl(NULL, VFIO_CHECK_EXTENSION, arg) <= 0) {
803 module_put(driver->ops->owner);
807 /* module reference holds the driver we're working on */
808 mutex_unlock(&vfio.iommu_drivers_lock);
810 data = driver->ops->open(arg);
813 module_put(driver->ops->owner);
814 goto skip_drivers_unlock;
817 ret = __vfio_container_attach_groups(container, driver, data);
819 container->iommu_driver = driver;
820 container->iommu_data = data;
822 driver->ops->release(data);
823 module_put(driver->ops->owner);
826 goto skip_drivers_unlock;
829 mutex_unlock(&vfio.iommu_drivers_lock);
831 mutex_unlock(&container->group_lock);
836 static long vfio_fops_unl_ioctl(struct file *filep,
837 unsigned int cmd, unsigned long arg)
839 struct vfio_container *container = filep->private_data;
840 struct vfio_iommu_driver *driver;
847 driver = container->iommu_driver;
848 data = container->iommu_data;
851 case VFIO_GET_API_VERSION:
852 ret = VFIO_API_VERSION;
854 case VFIO_CHECK_EXTENSION:
855 ret = vfio_ioctl_check_extension(container, arg);
858 ret = vfio_ioctl_set_iommu(container, arg);
861 if (driver) /* passthrough all unrecognized ioctls */
862 ret = driver->ops->ioctl(data, cmd, arg);
869 static long vfio_fops_compat_ioctl(struct file *filep,
870 unsigned int cmd, unsigned long arg)
872 arg = (unsigned long)compat_ptr(arg);
873 return vfio_fops_unl_ioctl(filep, cmd, arg);
875 #endif /* CONFIG_COMPAT */
877 static int vfio_fops_open(struct inode *inode, struct file *filep)
879 struct vfio_container *container;
881 container = kzalloc(sizeof(*container), GFP_KERNEL);
885 INIT_LIST_HEAD(&container->group_list);
886 mutex_init(&container->group_lock);
887 kref_init(&container->kref);
889 filep->private_data = container;
894 static int vfio_fops_release(struct inode *inode, struct file *filep)
896 struct vfio_container *container = filep->private_data;
898 filep->private_data = NULL;
900 vfio_container_put(container);
906 * Once an iommu driver is set, we optionally pass read/write/mmap
907 * on to the driver, allowing management interfaces beyond ioctl.
909 static ssize_t vfio_fops_read(struct file *filep, char __user *buf,
910 size_t count, loff_t *ppos)
912 struct vfio_container *container = filep->private_data;
913 struct vfio_iommu_driver *driver = container->iommu_driver;
915 if (unlikely(!driver || !driver->ops->read))
918 return driver->ops->read(container->iommu_data, buf, count, ppos);
921 static ssize_t vfio_fops_write(struct file *filep, const char __user *buf,
922 size_t count, loff_t *ppos)
924 struct vfio_container *container = filep->private_data;
925 struct vfio_iommu_driver *driver = container->iommu_driver;
927 if (unlikely(!driver || !driver->ops->write))
930 return driver->ops->write(container->iommu_data, buf, count, ppos);
933 static int vfio_fops_mmap(struct file *filep, struct vm_area_struct *vma)
935 struct vfio_container *container = filep->private_data;
936 struct vfio_iommu_driver *driver = container->iommu_driver;
938 if (unlikely(!driver || !driver->ops->mmap))
941 return driver->ops->mmap(container->iommu_data, vma);
944 static 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,
952 .compat_ioctl = vfio_fops_compat_ioctl,
954 .mmap = vfio_fops_mmap,
958 * VFIO Group fd, /dev/vfio/$GROUP
960 static void __vfio_group_unset_container(struct vfio_group *group)
962 struct vfio_container *container = group->container;
963 struct vfio_iommu_driver *driver;
965 mutex_lock(&container->group_lock);
967 driver = container->iommu_driver;
969 driver->ops->detach_group(container->iommu_data,
972 group->container = NULL;
973 list_del(&group->container_next);
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;
983 mutex_unlock(&container->group_lock);
985 vfio_container_put(container);
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.
994 static int vfio_group_unset_container(struct vfio_group *group)
996 int users = atomic_cmpxchg(&group->container_users, 1, 0);
1003 __vfio_group_unset_container(group);
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.
1014 static void vfio_group_try_dissolve_container(struct vfio_group *group)
1016 if (0 == atomic_dec_if_positive(&group->container_users))
1017 __vfio_group_unset_container(group);
1020 static int vfio_group_set_container(struct vfio_group *group, int container_fd)
1023 struct vfio_container *container;
1024 struct vfio_iommu_driver *driver;
1027 if (atomic_read(&group->container_users))
1030 filep = fget(container_fd);
1034 /* Sanity check, is this really our fd? */
1035 if (filep->f_op != &vfio_fops) {
1040 container = filep->private_data;
1041 WARN_ON(!container); /* fget ensures we don't race vfio_release */
1043 mutex_lock(&container->group_lock);
1045 driver = container->iommu_driver;
1047 ret = driver->ops->attach_group(container->iommu_data,
1048 group->iommu_group);
1053 group->container = container;
1054 list_add(&group->container_next, &container->group_list);
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);
1061 mutex_unlock(&container->group_lock);
1067 static bool vfio_group_viable(struct vfio_group *group)
1069 return (iommu_group_for_each_dev(group->iommu_group,
1070 group, vfio_dev_viable) == 0);
1073 static const struct file_operations vfio_device_fops;
1075 static int vfio_group_get_device_fd(struct vfio_group *group, char *buf)
1077 struct vfio_device *device;
1081 if (0 == atomic_read(&group->container_users) ||
1082 !group->container->iommu_driver || !vfio_group_viable(group))
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))
1090 ret = device->ops->open(device->device_data);
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
1097 ret = get_unused_fd();
1099 device->ops->release(device->device_data);
1103 filep = anon_inode_getfile("[vfio-device]", &vfio_device_fops,
1105 if (IS_ERR(filep)) {
1107 ret = PTR_ERR(filep);
1108 device->ops->release(device->device_data);
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.
1117 filep->f_mode |= (FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE);
1119 fd_install(ret, filep);
1121 vfio_device_get(device);
1122 atomic_inc(&group->container_users);
1125 mutex_unlock(&group->device_lock);
1130 static long vfio_group_fops_unl_ioctl(struct file *filep,
1131 unsigned int cmd, unsigned long arg)
1133 struct vfio_group *group = filep->private_data;
1137 case VFIO_GROUP_GET_STATUS:
1139 struct vfio_group_status status;
1140 unsigned long minsz;
1142 minsz = offsetofend(struct vfio_group_status, flags);
1144 if (copy_from_user(&status, (void __user *)arg, minsz))
1147 if (status.argsz < minsz)
1152 if (vfio_group_viable(group))
1153 status.flags |= VFIO_GROUP_FLAGS_VIABLE;
1155 if (group->container)
1156 status.flags |= VFIO_GROUP_FLAGS_CONTAINER_SET;
1158 if (copy_to_user((void __user *)arg, &status, minsz))
1164 case VFIO_GROUP_SET_CONTAINER:
1168 if (get_user(fd, (int __user *)arg))
1174 ret = vfio_group_set_container(group, fd);
1177 case VFIO_GROUP_UNSET_CONTAINER:
1178 ret = vfio_group_unset_container(group);
1180 case VFIO_GROUP_GET_DEVICE_FD:
1184 buf = strndup_user((const char __user *)arg, PAGE_SIZE);
1186 return PTR_ERR(buf);
1188 ret = vfio_group_get_device_fd(group, buf);
1197 #ifdef CONFIG_COMPAT
1198 static long vfio_group_fops_compat_ioctl(struct file *filep,
1199 unsigned int cmd, unsigned long arg)
1201 arg = (unsigned long)compat_ptr(arg);
1202 return vfio_group_fops_unl_ioctl(filep, cmd, arg);
1204 #endif /* CONFIG_COMPAT */
1206 static int vfio_group_fops_open(struct inode *inode, struct file *filep)
1208 struct vfio_group *group;
1210 group = vfio_group_get_from_minor(iminor(inode));
1214 if (group->container) {
1215 vfio_group_put(group);
1219 filep->private_data = group;
1224 static int vfio_group_fops_release(struct inode *inode, struct file *filep)
1226 struct vfio_group *group = filep->private_data;
1228 filep->private_data = NULL;
1230 vfio_group_try_dissolve_container(group);
1232 vfio_group_put(group);
1237 static 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,
1243 .open = vfio_group_fops_open,
1244 .release = vfio_group_fops_release,
1250 static int vfio_device_fops_release(struct inode *inode, struct file *filep)
1252 struct vfio_device *device = filep->private_data;
1254 device->ops->release(device->device_data);
1256 vfio_group_try_dissolve_container(device->group);
1258 vfio_device_put(device);
1263 static long vfio_device_fops_unl_ioctl(struct file *filep,
1264 unsigned int cmd, unsigned long arg)
1266 struct vfio_device *device = filep->private_data;
1268 if (unlikely(!device->ops->ioctl))
1271 return device->ops->ioctl(device->device_data, cmd, arg);
1274 static ssize_t vfio_device_fops_read(struct file *filep, char __user *buf,
1275 size_t count, loff_t *ppos)
1277 struct vfio_device *device = filep->private_data;
1279 if (unlikely(!device->ops->read))
1282 return device->ops->read(device->device_data, buf, count, ppos);
1285 static ssize_t vfio_device_fops_write(struct file *filep,
1286 const char __user *buf,
1287 size_t count, loff_t *ppos)
1289 struct vfio_device *device = filep->private_data;
1291 if (unlikely(!device->ops->write))
1294 return device->ops->write(device->device_data, buf, count, ppos);
1297 static int vfio_device_fops_mmap(struct file *filep, struct vm_area_struct *vma)
1299 struct vfio_device *device = filep->private_data;
1301 if (unlikely(!device->ops->mmap))
1304 return device->ops->mmap(device->device_data, vma);
1307 #ifdef CONFIG_COMPAT
1308 static long vfio_device_fops_compat_ioctl(struct file *filep,
1309 unsigned int cmd, unsigned long arg)
1311 arg = (unsigned long)compat_ptr(arg);
1312 return vfio_device_fops_unl_ioctl(filep, cmd, arg);
1314 #endif /* CONFIG_COMPAT */
1316 static 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,
1325 .mmap = vfio_device_fops_mmap,
1329 * Module/class support
1331 static char *vfio_devnode(struct device *dev, umode_t *mode)
1333 return kasprintf(GFP_KERNEL, "vfio/%s", dev_name(dev));
1336 static int __init vfio_init(void)
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);
1347 vfio.class = class_create(THIS_MODULE, "vfio");
1348 if (IS_ERR(vfio.class)) {
1349 ret = PTR_ERR(vfio.class);
1353 vfio.class->devnode = vfio_devnode;
1355 ret = alloc_chrdev_region(&vfio.devt, 0, MINORMASK, "vfio");
1357 goto err_base_chrdev;
1359 cdev_init(&vfio.cdev, &vfio_fops);
1360 ret = cdev_add(&vfio.cdev, vfio.devt, 1);
1364 vfio.dev = device_create(vfio.class, NULL, vfio.devt, NULL, "vfio");
1365 if (IS_ERR(vfio.dev)) {
1366 ret = PTR_ERR(vfio.dev);
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);
1375 goto err_groups_cdev;
1377 pr_info(DRIVER_DESC " version: " DRIVER_VERSION "\n");
1380 * Attempt to load known iommu-drivers. This gives us a working
1381 * environment without the user needing to explicitly load iommu
1384 request_module_nowait("vfio_iommu_type1");
1389 device_destroy(vfio.class, vfio.devt);
1391 cdev_del(&vfio.cdev);
1393 unregister_chrdev_region(vfio.devt, MINORMASK);
1395 class_destroy(vfio.class);
1401 static void __exit vfio_cleanup(void)
1403 WARN_ON(!list_empty(&vfio.group_list));
1405 idr_destroy(&vfio.group_idr);
1406 cdev_del(&vfio.group_cdev);
1407 device_destroy(vfio.class, vfio.devt);
1408 cdev_del(&vfio.cdev);
1409 unregister_chrdev_region(vfio.devt, MINORMASK);
1410 class_destroy(vfio.class);
1414 module_init(vfio_init);
1415 module_exit(vfio_cleanup);
1417 MODULE_VERSION(DRIVER_VERSION);
1418 MODULE_LICENSE("GPL v2");
1419 MODULE_AUTHOR(DRIVER_AUTHOR);
1420 MODULE_DESCRIPTION(DRIVER_DESC);