group.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * VFIO core
  4 *
  5 * Copyright (C) 2012 Red Hat, Inc.  All rights reserved.
  6 *     Author: Alex Williamson <alex.williamson@redhat.com>
  7 *
  8 * Derived from original vfio:
  9 * Copyright 2010 Cisco Systems, Inc.  All rights reserved.
 10 * Author: Tom Lyon, pugs@cisco.com
 11 */
 12
 13#include <linux/vfio.h>
 14#include <linux/iommufd.h>
 15#include <linux/anon_inodes.h>
 16#include "vfio.h"
 17
 18static struct vfio {
 19	struct class			*class;
 20	struct list_head		group_list;
 21	struct mutex			group_lock; /* locks group_list */
 22	struct ida			group_ida;
 23	dev_t				group_devt;
 24} vfio;
 25
 26static struct vfio_device *vfio_device_get_from_name(struct vfio_group *group,
 27						     char *buf)
 28{
 29	struct vfio_device *it, *device = ERR_PTR(-ENODEV);
 30
 31	mutex_lock(&group->device_lock);
 32	list_for_each_entry(it, &group->device_list, group_next) {
 33		int ret;
 34
 35		if (it->ops->match) {
 36			ret = it->ops->match(it, buf);
 37			if (ret < 0) {
 38				device = ERR_PTR(ret);
 39				break;
 40			}
 41		} else {
 42			ret = !strcmp(dev_name(it->dev), buf);
 43		}
 44
 45		if (ret && vfio_device_try_get_registration(it)) {
 46			device = it;
 47			break;
 48		}
 49	}
 50	mutex_unlock(&group->device_lock);
 51
 52	return device;
 53}
 54
 55/*
 56 * VFIO Group fd, /dev/vfio/$GROUP
 57 */
 58static bool vfio_group_has_iommu(struct vfio_group *group)
 59{
 60	lockdep_assert_held(&group->group_lock);
 61	/*
 62	 * There can only be users if there is a container, and if there is a
 63	 * container there must be users.
 64	 */
 65	WARN_ON(!group->container != !group->container_users);
 66
 67	return group->container || group->iommufd;
 68}
 69
 70/*
 71 * VFIO_GROUP_UNSET_CONTAINER should fail if there are other users or
 72 * if there was no container to unset.  Since the ioctl is called on
 73 * the group, we know that still exists, therefore the only valid
 74 * transition here is 1->0.
 75 */
 76static int vfio_group_ioctl_unset_container(struct vfio_group *group)
 77{
 78	int ret = 0;
 79
 80	mutex_lock(&group->group_lock);
 81	if (!vfio_group_has_iommu(group)) {
 82		ret = -EINVAL;
 83		goto out_unlock;
 84	}
 85	if (group->container) {
 86		if (group->container_users != 1) {
 87			ret = -EBUSY;
 88			goto out_unlock;
 89		}
 90		vfio_group_detach_container(group);
 91	}
 92	if (group->iommufd) {
 93		iommufd_ctx_put(group->iommufd);
 94		group->iommufd = NULL;
 95	}
 96
 97out_unlock:
 98	mutex_unlock(&group->group_lock);
 99	return ret;
100}
101
102static int vfio_group_ioctl_set_container(struct vfio_group *group,
103					  int __user *arg)
104{
105	struct vfio_container *container;
106	struct iommufd_ctx *iommufd;
107	int ret;
108	int fd;
109
110	if (get_user(fd, arg))
111		return -EFAULT;
112
113	CLASS(fd, f)(fd);
114	if (fd_empty(f))
115		return -EBADF;
116
117	mutex_lock(&group->group_lock);
118	if (vfio_group_has_iommu(group)) {
119		ret = -EINVAL;
120		goto out_unlock;
121	}
122	if (!group->iommu_group) {
123		ret = -ENODEV;
124		goto out_unlock;
125	}
126
127	container = vfio_container_from_file(fd_file(f));
128	if (container) {
129		ret = vfio_container_attach_group(container, group);
130		goto out_unlock;
131	}
132
133	iommufd = iommufd_ctx_from_file(fd_file(f));
134	if (!IS_ERR(iommufd)) {
135		if (IS_ENABLED(CONFIG_VFIO_NOIOMMU) &&
136		    group->type == VFIO_NO_IOMMU)
137			ret = iommufd_vfio_compat_set_no_iommu(iommufd);
138		else
139			ret = iommufd_vfio_compat_ioas_create(iommufd);
140
141		if (ret) {
142			iommufd_ctx_put(iommufd);
143			goto out_unlock;
144		}
145
146		group->iommufd = iommufd;
147		goto out_unlock;
148	}
149
150	/* The FD passed is not recognized. */
151	ret = -EBADFD;
152
153out_unlock:
154	mutex_unlock(&group->group_lock);
155	return ret;
156}
157
158static void vfio_device_group_get_kvm_safe(struct vfio_device *device)
159{
160	spin_lock(&device->group->kvm_ref_lock);
161	vfio_device_get_kvm_safe(device, device->group->kvm);
162	spin_unlock(&device->group->kvm_ref_lock);
163}
164
165static int vfio_df_group_open(struct vfio_device_file *df)
166{
167	struct vfio_device *device = df->device;
168	int ret;
169
170	mutex_lock(&device->group->group_lock);
171	if (!vfio_group_has_iommu(device->group)) {
172		ret = -EINVAL;
173		goto out_unlock;
174	}
175
176	mutex_lock(&device->dev_set->lock);
177
178	/*
179	 * Before the first device open, get the KVM pointer currently
180	 * associated with the group (if there is one) and obtain a reference
181	 * now that will be held until the open_count reaches 0 again.  Save
182	 * the pointer in the device for use by drivers.
183	 */
184	if (device->open_count == 0)
185		vfio_device_group_get_kvm_safe(device);
186
187	df->iommufd = device->group->iommufd;
188	if (df->iommufd && vfio_device_is_noiommu(device) && device->open_count == 0) {
189		/*
190		 * Require no compat ioas to be assigned to proceed.  The basic
191		 * statement is that the user cannot have done something that
192		 * implies they expected translation to exist
193		 */
194		if (!capable(CAP_SYS_RAWIO) ||
195		    vfio_iommufd_device_has_compat_ioas(device, df->iommufd)) {
196			ret = -EPERM;
197			goto out_put_kvm;
198		}
199	}
200
201	ret = vfio_df_open(df);
202	if (ret)
203		goto out_put_kvm;
204
205	if (df->iommufd && device->open_count == 1) {
206		ret = vfio_iommufd_compat_attach_ioas(device, df->iommufd);
207		if (ret)
208			goto out_close_device;
209	}
210
211	/*
212	 * Paired with smp_load_acquire() in vfio_device_fops::ioctl/
213	 * read/write/mmap and vfio_file_has_device_access()
214	 */
215	smp_store_release(&df->access_granted, true);
216
217	mutex_unlock(&device->dev_set->lock);
218	mutex_unlock(&device->group->group_lock);
219	return 0;
220
221out_close_device:
222	vfio_df_close(df);
223out_put_kvm:
224	df->iommufd = NULL;
225	if (device->open_count == 0)
226		vfio_device_put_kvm(device);
227	mutex_unlock(&device->dev_set->lock);
228out_unlock:
229	mutex_unlock(&device->group->group_lock);
230	return ret;
231}
232
233void vfio_df_group_close(struct vfio_device_file *df)
234{
235	struct vfio_device *device = df->device;
236
237	mutex_lock(&device->group->group_lock);
238	mutex_lock(&device->dev_set->lock);
239
240	vfio_df_close(df);
241	df->iommufd = NULL;
242
243	if (device->open_count == 0)
244		vfio_device_put_kvm(device);
245
246	mutex_unlock(&device->dev_set->lock);
247	mutex_unlock(&device->group->group_lock);
248}
249
250static struct file *vfio_device_open_file(struct vfio_device *device)
251{
252	struct vfio_device_file *df;
253	struct file *filep;
254	int ret;
255
256	df = vfio_allocate_device_file(device);
257	if (IS_ERR(df)) {
258		ret = PTR_ERR(df);
259		goto err_out;
260	}
261
262	df->group = device->group;
263
264	ret = vfio_df_group_open(df);
265	if (ret)
266		goto err_free;
267
268	filep = anon_inode_getfile_fmode("[vfio-device]", &vfio_device_fops,
269				   df, O_RDWR, FMODE_PREAD | FMODE_PWRITE);
270	if (IS_ERR(filep)) {
271		ret = PTR_ERR(filep);
272		goto err_close_device;
273	}
274	/*
275	 * Use the pseudo fs inode on the device to link all mmaps
276	 * to the same address space, allowing us to unmap all vmas
277	 * associated to this device using unmap_mapping_range().
278	 */
279	filep->f_mapping = device->inode->i_mapping;
280
281	if (device->group->type == VFIO_NO_IOMMU)
282		dev_warn(device->dev, "vfio-noiommu device opened by user "
283			 "(%s:%d)\n", current->comm, task_pid_nr(current));
284	/*
285	 * On success the ref of device is moved to the file and
286	 * put in vfio_device_fops_release()
287	 */
288	return filep;
289
290err_close_device:
291	vfio_df_group_close(df);
292err_free:
293	kfree(df);
294err_out:
295	return ERR_PTR(ret);
296}
297
298static int vfio_group_ioctl_get_device_fd(struct vfio_group *group,
299					  char __user *arg)
300{
301	struct vfio_device *device;
302	char *buf;
303	int fd;
304
305	buf = strndup_user(arg, PAGE_SIZE);
306	if (IS_ERR(buf))
307		return PTR_ERR(buf);
308
309	device = vfio_device_get_from_name(group, buf);
310	kfree(buf);
311	if (IS_ERR(device))
312		return PTR_ERR(device);
313
314	fd = FD_ADD(O_CLOEXEC, vfio_device_open_file(device));
315	if (fd < 0)
316		vfio_device_put_registration(device);
317	return fd;
318}
319
320static int vfio_group_ioctl_get_status(struct vfio_group *group,
321				       struct vfio_group_status __user *arg)
322{
323	unsigned long minsz = offsetofend(struct vfio_group_status, flags);
324	struct vfio_group_status status;
325
326	if (copy_from_user(&status, arg, minsz))
327		return -EFAULT;
328
329	if (status.argsz < minsz)
330		return -EINVAL;
331
332	status.flags = 0;
333
334	mutex_lock(&group->group_lock);
335	if (!group->iommu_group) {
336		mutex_unlock(&group->group_lock);
337		return -ENODEV;
338	}
339
340	/*
341	 * With the container FD the iommu_group_claim_dma_owner() is done
342	 * during SET_CONTAINER but for IOMMFD this is done during
343	 * VFIO_GROUP_GET_DEVICE_FD. Meaning that with iommufd
344	 * VFIO_GROUP_FLAGS_VIABLE could be set but GET_DEVICE_FD will fail due
345	 * to viability.
346	 */
347	if (vfio_group_has_iommu(group))
348		status.flags |= VFIO_GROUP_FLAGS_CONTAINER_SET |
349				VFIO_GROUP_FLAGS_VIABLE;
350	else if (!iommu_group_dma_owner_claimed(group->iommu_group))
351		status.flags |= VFIO_GROUP_FLAGS_VIABLE;
352	mutex_unlock(&group->group_lock);
353
354	if (copy_to_user(arg, &status, minsz))
355		return -EFAULT;
356	return 0;
357}
358
359static long vfio_group_fops_unl_ioctl(struct file *filep,
360				      unsigned int cmd, unsigned long arg)
361{
362	struct vfio_group *group = filep->private_data;
363	void __user *uarg = (void __user *)arg;
364
365	switch (cmd) {
366	case VFIO_GROUP_GET_DEVICE_FD:
367		return vfio_group_ioctl_get_device_fd(group, uarg);
368	case VFIO_GROUP_GET_STATUS:
369		return vfio_group_ioctl_get_status(group, uarg);
370	case VFIO_GROUP_SET_CONTAINER:
371		return vfio_group_ioctl_set_container(group, uarg);
372	case VFIO_GROUP_UNSET_CONTAINER:
373		return vfio_group_ioctl_unset_container(group);
374	default:
375		return -ENOTTY;
376	}
377}
378
379int vfio_device_block_group(struct vfio_device *device)
380{
381	struct vfio_group *group = device->group;
382	int ret = 0;
383
384	mutex_lock(&group->group_lock);
385	if (group->opened_file) {
386		ret = -EBUSY;
387		goto out_unlock;
388	}
389
390	group->cdev_device_open_cnt++;
391
392out_unlock:
393	mutex_unlock(&group->group_lock);
394	return ret;
395}
396
397void vfio_device_unblock_group(struct vfio_device *device)
398{
399	struct vfio_group *group = device->group;
400
401	mutex_lock(&group->group_lock);
402	group->cdev_device_open_cnt--;
403	mutex_unlock(&group->group_lock);
404}
405
406static int vfio_group_fops_open(struct inode *inode, struct file *filep)
407{
408	struct vfio_group *group =
409		container_of(inode->i_cdev, struct vfio_group, cdev);
410	int ret;
411
412	mutex_lock(&group->group_lock);
413
414	/*
415	 * drivers can be zero if this races with vfio_device_remove_group(), it
416	 * will be stable at 0 under the group rwsem
417	 */
418	if (refcount_read(&group->drivers) == 0) {
419		ret = -ENODEV;
420		goto out_unlock;
421	}
422
423	if (group->type == VFIO_NO_IOMMU && !capable(CAP_SYS_RAWIO)) {
424		ret = -EPERM;
425		goto out_unlock;
426	}
427
428	if (group->cdev_device_open_cnt) {
429		ret = -EBUSY;
430		goto out_unlock;
431	}
432
433	/*
434	 * Do we need multiple instances of the group open?  Seems not.
435	 */
436	if (group->opened_file) {
437		ret = -EBUSY;
438		goto out_unlock;
439	}
440	group->opened_file = filep;
441	filep->private_data = group;
442	ret = 0;
443out_unlock:
444	mutex_unlock(&group->group_lock);
445	return ret;
446}
447
448static int vfio_group_fops_release(struct inode *inode, struct file *filep)
449{
450	struct vfio_group *group = filep->private_data;
451
452	filep->private_data = NULL;
453
454	mutex_lock(&group->group_lock);
455	/*
456	 * Device FDs hold a group file reference, therefore the group release
457	 * is only called when there are no open devices.
458	 */
459	WARN_ON(group->notifier.head);
460	if (group->container)
461		vfio_group_detach_container(group);
462	if (group->iommufd) {
463		iommufd_ctx_put(group->iommufd);
464		group->iommufd = NULL;
465	}
466	group->opened_file = NULL;
467	mutex_unlock(&group->group_lock);
468	return 0;
469}
470
471static const struct file_operations vfio_group_fops = {
472	.owner		= THIS_MODULE,
473	.unlocked_ioctl	= vfio_group_fops_unl_ioctl,
474	.compat_ioctl	= compat_ptr_ioctl,
475	.open		= vfio_group_fops_open,
476	.release	= vfio_group_fops_release,
477};
478
479/*
480 * Group objects - create, release, get, put, search
481 */
482static struct vfio_group *
483vfio_group_find_from_iommu(struct iommu_group *iommu_group)
484{
485	struct vfio_group *group;
486
487	lockdep_assert_held(&vfio.group_lock);
488
489	/*
490	 * group->iommu_group from the vfio.group_list cannot be NULL
491	 * under the vfio.group_lock.
492	 */
493	list_for_each_entry(group, &vfio.group_list, vfio_next) {
494		if (group->iommu_group == iommu_group)
495			return group;
496	}
497	return NULL;
498}
499
500static void vfio_group_release(struct device *dev)
501{
502	struct vfio_group *group = container_of(dev, struct vfio_group, dev);
503
504	mutex_destroy(&group->device_lock);
505	mutex_destroy(&group->group_lock);
506	WARN_ON(group->iommu_group);
507	WARN_ON(group->cdev_device_open_cnt);
508	ida_free(&vfio.group_ida, MINOR(group->dev.devt));
509	kfree(group);
510}
511
512static struct vfio_group *vfio_group_alloc(struct iommu_group *iommu_group,
513					   enum vfio_group_type type)
514{
515	struct vfio_group *group;
516	int minor;
517
518	group = kzalloc(sizeof(*group), GFP_KERNEL);
519	if (!group)
520		return ERR_PTR(-ENOMEM);
521
522	minor = ida_alloc_max(&vfio.group_ida, MINORMASK, GFP_KERNEL);
523	if (minor < 0) {
524		kfree(group);
525		return ERR_PTR(minor);
526	}
527
528	device_initialize(&group->dev);
529	group->dev.devt = MKDEV(MAJOR(vfio.group_devt), minor);
530	group->dev.class = vfio.class;
531	group->dev.release = vfio_group_release;
532	cdev_init(&group->cdev, &vfio_group_fops);
533	group->cdev.owner = THIS_MODULE;
534
535	refcount_set(&group->drivers, 1);
536	mutex_init(&group->group_lock);
537	spin_lock_init(&group->kvm_ref_lock);
538	INIT_LIST_HEAD(&group->device_list);
539	mutex_init(&group->device_lock);
540	group->iommu_group = iommu_group;
541	/* put in vfio_group_release() */
542	iommu_group_ref_get(iommu_group);
543	group->type = type;
544	BLOCKING_INIT_NOTIFIER_HEAD(&group->notifier);
545
546	return group;
547}
548
549static struct vfio_group *vfio_create_group(struct iommu_group *iommu_group,
550		enum vfio_group_type type)
551{
552	struct vfio_group *group;
553	struct vfio_group *ret;
554	int err;
555
556	lockdep_assert_held(&vfio.group_lock);
557
558	group = vfio_group_alloc(iommu_group, type);
559	if (IS_ERR(group))
560		return group;
561
562	err = dev_set_name(&group->dev, "%s%d",
563			   group->type == VFIO_NO_IOMMU ? "noiommu-" : "",
564			   iommu_group_id(iommu_group));
565	if (err) {
566		ret = ERR_PTR(err);
567		goto err_put;
568	}
569
570	err = cdev_device_add(&group->cdev, &group->dev);
571	if (err) {
572		ret = ERR_PTR(err);
573		goto err_put;
574	}
575
576	list_add(&group->vfio_next, &vfio.group_list);
577
578	return group;
579
580err_put:
581	put_device(&group->dev);
582	return ret;
583}
584
585static struct vfio_group *vfio_noiommu_group_alloc(struct device *dev,
586		enum vfio_group_type type)
587{
588	struct iommu_group *iommu_group;
589	struct vfio_group *group;
590	int ret;
591
592	iommu_group = iommu_group_alloc();
593	if (IS_ERR(iommu_group))
594		return ERR_CAST(iommu_group);
595
596	ret = iommu_group_set_name(iommu_group, "vfio-noiommu");
597	if (ret)
598		goto out_put_group;
599	ret = iommu_group_add_device(iommu_group, dev);
600	if (ret)
601		goto out_put_group;
602
603	mutex_lock(&vfio.group_lock);
604	group = vfio_create_group(iommu_group, type);
605	mutex_unlock(&vfio.group_lock);
606	if (IS_ERR(group)) {
607		ret = PTR_ERR(group);
608		goto out_remove_device;
609	}
610	iommu_group_put(iommu_group);
611	return group;
612
613out_remove_device:
614	iommu_group_remove_device(dev);
615out_put_group:
616	iommu_group_put(iommu_group);
617	return ERR_PTR(ret);
618}
619
620static bool vfio_group_has_device(struct vfio_group *group, struct device *dev)
621{
622	struct vfio_device *device;
623
624	mutex_lock(&group->device_lock);
625	list_for_each_entry(device, &group->device_list, group_next) {
626		if (device->dev == dev) {
627			mutex_unlock(&group->device_lock);
628			return true;
629		}
630	}
631	mutex_unlock(&group->device_lock);
632	return false;
633}
634
635static struct vfio_group *vfio_group_find_or_alloc(struct device *dev)
636{
637	struct iommu_group *iommu_group;
638	struct vfio_group *group;
639
640	iommu_group = iommu_group_get(dev);
641	if (!iommu_group && vfio_noiommu) {
642		/*
643		 * With noiommu enabled, create an IOMMU group for devices that
644		 * don't already have one, implying no IOMMU hardware/driver
645		 * exists.  Taint the kernel because we're about to give a DMA
646		 * capable device to a user without IOMMU protection.
647		 */
648		group = vfio_noiommu_group_alloc(dev, VFIO_NO_IOMMU);
649		if (!IS_ERR(group)) {
650			add_taint(TAINT_USER, LOCKDEP_STILL_OK);
651			dev_warn(dev, "Adding kernel taint for vfio-noiommu group on device\n");
652		}
653		return group;
654	}
655
656	if (!iommu_group)
657		return ERR_PTR(-EINVAL);
658
659	mutex_lock(&vfio.group_lock);
660	group = vfio_group_find_from_iommu(iommu_group);
661	if (group) {
662		if (WARN_ON(vfio_group_has_device(group, dev)))
663			group = ERR_PTR(-EINVAL);
664		else
665			refcount_inc(&group->drivers);
666	} else {
667		group = vfio_create_group(iommu_group, VFIO_IOMMU);
668	}
669	mutex_unlock(&vfio.group_lock);
670
671	/* The vfio_group holds a reference to the iommu_group */
672	iommu_group_put(iommu_group);
673	return group;
674}
675
676int vfio_device_set_group(struct vfio_device *device,
677			  enum vfio_group_type type)
678{
679	struct vfio_group *group;
680
681	if (type == VFIO_IOMMU)
682		group = vfio_group_find_or_alloc(device->dev);
683	else
684		group = vfio_noiommu_group_alloc(device->dev, type);
685
686	if (IS_ERR(group))
687		return PTR_ERR(group);
688
689	/* Our reference on group is moved to the device */
690	device->group = group;
691	return 0;
692}
693
694void vfio_device_remove_group(struct vfio_device *device)
695{
696	struct vfio_group *group = device->group;
697	struct iommu_group *iommu_group;
698
699	if (group->type == VFIO_NO_IOMMU || group->type == VFIO_EMULATED_IOMMU)
700		iommu_group_remove_device(device->dev);
701
702	/* Pairs with vfio_create_group() / vfio_group_get_from_iommu() */
703	if (!refcount_dec_and_mutex_lock(&group->drivers, &vfio.group_lock))
704		return;
705	list_del(&group->vfio_next);
706
707	/*
708	 * We could concurrently probe another driver in the group that might
709	 * race vfio_device_remove_group() with vfio_get_group(), so we have to
710	 * ensure that the sysfs is all cleaned up under lock otherwise the
711	 * cdev_device_add() will fail due to the name aready existing.
712	 */
713	cdev_device_del(&group->cdev, &group->dev);
714
715	mutex_lock(&group->group_lock);
716	/*
717	 * These data structures all have paired operations that can only be
718	 * undone when the caller holds a live reference on the device. Since
719	 * all pairs must be undone these WARN_ON's indicate some caller did not
720	 * properly hold the group reference.
721	 */
722	WARN_ON(!list_empty(&group->device_list));
723	WARN_ON(group->notifier.head);
724
725	/*
726	 * Revoke all users of group->iommu_group. At this point we know there
727	 * are no devices active because we are unplugging the last one. Setting
728	 * iommu_group to NULL blocks all new users.
729	 */
730	if (group->container)
731		vfio_group_detach_container(group);
732	iommu_group = group->iommu_group;
733	group->iommu_group = NULL;
734	mutex_unlock(&group->group_lock);
735	mutex_unlock(&vfio.group_lock);
736
737	iommu_group_put(iommu_group);
738	put_device(&group->dev);
739}
740
741void vfio_device_group_register(struct vfio_device *device)
742{
743	mutex_lock(&device->group->device_lock);
744	list_add(&device->group_next, &device->group->device_list);
745	mutex_unlock(&device->group->device_lock);
746}
747
748void vfio_device_group_unregister(struct vfio_device *device)
749{
750	mutex_lock(&device->group->device_lock);
751	list_del(&device->group_next);
752	mutex_unlock(&device->group->device_lock);
753}
754
755int vfio_device_group_use_iommu(struct vfio_device *device)
756{
757	struct vfio_group *group = device->group;
758	int ret = 0;
759
760	lockdep_assert_held(&group->group_lock);
761
762	if (WARN_ON(!group->container))
763		return -EINVAL;
764
765	ret = vfio_group_use_container(group);
766	if (ret)
767		return ret;
768	vfio_device_container_register(device);
769	return 0;
770}
771
772void vfio_device_group_unuse_iommu(struct vfio_device *device)
773{
774	struct vfio_group *group = device->group;
775
776	lockdep_assert_held(&group->group_lock);
777
778	if (WARN_ON(!group->container))
779		return;
780
781	vfio_device_container_unregister(device);
782	vfio_group_unuse_container(group);
783}
784
785bool vfio_device_has_container(struct vfio_device *device)
786{
787	return device->group->container;
788}
789
790struct vfio_group *vfio_group_from_file(struct file *file)
791{
792	struct vfio_group *group = file->private_data;
793
794	if (file->f_op != &vfio_group_fops)
795		return NULL;
796	return group;
797}
798
799/**
800 * vfio_file_iommu_group - Return the struct iommu_group for the vfio group file
801 * @file: VFIO group file
802 *
803 * The returned iommu_group is valid as long as a ref is held on the file. This
804 * returns a reference on the group. This function is deprecated, only the SPAPR
805 * path in kvm should call it.
806 */
807struct iommu_group *vfio_file_iommu_group(struct file *file)
808{
809	struct vfio_group *group = vfio_group_from_file(file);
810	struct iommu_group *iommu_group = NULL;
811
812	if (!IS_ENABLED(CONFIG_SPAPR_TCE_IOMMU))
813		return NULL;
814
815	if (!group)
816		return NULL;
817
818	mutex_lock(&group->group_lock);
819	if (group->iommu_group) {
820		iommu_group = group->iommu_group;
821		iommu_group_ref_get(iommu_group);
822	}
823	mutex_unlock(&group->group_lock);
824	return iommu_group;
825}
826EXPORT_SYMBOL_GPL(vfio_file_iommu_group);
827
828/**
829 * vfio_file_is_group - True if the file is a vfio group file
830 * @file: VFIO group file
831 */
832bool vfio_file_is_group(struct file *file)
833{
834	return vfio_group_from_file(file);
835}
836EXPORT_SYMBOL_GPL(vfio_file_is_group);
837
838bool vfio_group_enforced_coherent(struct vfio_group *group)
839{
840	struct vfio_device *device;
841	bool ret = true;
842
843	/*
844	 * If the device does not have IOMMU_CAP_ENFORCE_CACHE_COHERENCY then
845	 * any domain later attached to it will also not support it. If the cap
846	 * is set then the iommu_domain eventually attached to the device/group
847	 * must use a domain with enforce_cache_coherency().
848	 */
849	mutex_lock(&group->device_lock);
850	list_for_each_entry(device, &group->device_list, group_next) {
851		if (!device_iommu_capable(device->dev,
852					  IOMMU_CAP_ENFORCE_CACHE_COHERENCY)) {
853			ret = false;
854			break;
855		}
856	}
857	mutex_unlock(&group->device_lock);
858	return ret;
859}
860
861void vfio_group_set_kvm(struct vfio_group *group, struct kvm *kvm)
862{
863	spin_lock(&group->kvm_ref_lock);
864	group->kvm = kvm;
865	spin_unlock(&group->kvm_ref_lock);
866}
867
868/**
869 * vfio_file_has_dev - True if the VFIO file is a handle for device
870 * @file: VFIO file to check
871 * @device: Device that must be part of the file
872 *
873 * Returns true if given file has permission to manipulate the given device.
874 */
875bool vfio_file_has_dev(struct file *file, struct vfio_device *device)
876{
877	struct vfio_group *group = vfio_group_from_file(file);
878
879	if (!group)
880		return false;
881
882	return group == device->group;
883}
884EXPORT_SYMBOL_GPL(vfio_file_has_dev);
885
886static char *vfio_devnode(const struct device *dev, umode_t *mode)
887{
888	return kasprintf(GFP_KERNEL, "vfio/%s", dev_name(dev));
889}
890
891int __init vfio_group_init(void)
892{
893	int ret;
894
895	ida_init(&vfio.group_ida);
896	mutex_init(&vfio.group_lock);
897	INIT_LIST_HEAD(&vfio.group_list);
898
899	ret = vfio_container_init();
900	if (ret)
901		return ret;
902
903	/* /dev/vfio/$GROUP */
904	vfio.class = class_create("vfio");
905	if (IS_ERR(vfio.class)) {
906		ret = PTR_ERR(vfio.class);
907		goto err_group_class;
908	}
909
910	vfio.class->devnode = vfio_devnode;
911
912	ret = alloc_chrdev_region(&vfio.group_devt, 0, MINORMASK + 1, "vfio");
913	if (ret)
914		goto err_alloc_chrdev;
915	return 0;
916
917err_alloc_chrdev:
918	class_destroy(vfio.class);
919	vfio.class = NULL;
920err_group_class:
921	vfio_container_cleanup();
922	return ret;
923}
924
925void vfio_group_cleanup(void)
926{
927	WARN_ON(!list_empty(&vfio.group_list));
928	ida_destroy(&vfio.group_ida);
929	unregister_chrdev_region(vfio.group_devt, MINORMASK + 1);
930	class_destroy(vfio.class);
931	vfio.class = NULL;
932	vfio_container_cleanup();
933}