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	struct fd f;
108	int ret;
109	int fd;
110
111	if (get_user(fd, arg))
112		return -EFAULT;
113
114	f = fdget(fd);
115	if (!f.file)
116		return -EBADF;
117
118	mutex_lock(&group->group_lock);
119	if (vfio_group_has_iommu(group)) {
120		ret = -EINVAL;
121		goto out_unlock;
122	}
123	if (!group->iommu_group) {
124		ret = -ENODEV;
125		goto out_unlock;
126	}
127
128	container = vfio_container_from_file(f.file);
129	if (container) {
130		ret = vfio_container_attach_group(container, group);
131		goto out_unlock;
132	}
133
134	iommufd = iommufd_ctx_from_file(f.file);
135	if (!IS_ERR(iommufd)) {
136		if (IS_ENABLED(CONFIG_VFIO_NOIOMMU) &&
137		    group->type == VFIO_NO_IOMMU)
138			ret = iommufd_vfio_compat_set_no_iommu(iommufd);
139		else
140			ret = iommufd_vfio_compat_ioas_create(iommufd);
141
 
142		if (ret) {
143			iommufd_ctx_put(iommufd);
144			goto out_unlock;
145		}
146
147		group->iommufd = iommufd;
148		goto out_unlock;
149	}
150
151	/* The FD passed is not recognized. */
152	ret = -EBADFD;
153
154out_unlock:
155	mutex_unlock(&group->group_lock);
156	fdput(f);
157	return ret;
158}
159
160static void vfio_device_group_get_kvm_safe(struct vfio_device *device)
161{
162	spin_lock(&device->group->kvm_ref_lock);
163	vfio_device_get_kvm_safe(device, device->group->kvm);
164	spin_unlock(&device->group->kvm_ref_lock);
165}
166
167static int vfio_df_group_open(struct vfio_device_file *df)
168{
169	struct vfio_device *device = df->device;
170	int ret;
171
172	mutex_lock(&device->group->group_lock);
173	if (!vfio_group_has_iommu(device->group)) {
174		ret = -EINVAL;
175		goto out_unlock;
176	}
177
178	mutex_lock(&device->dev_set->lock);
179
180	/*
181	 * Before the first device open, get the KVM pointer currently
182	 * associated with the group (if there is one) and obtain a reference
183	 * now that will be held until the open_count reaches 0 again.  Save
184	 * the pointer in the device for use by drivers.
185	 */
186	if (device->open_count == 0)
187		vfio_device_group_get_kvm_safe(device);
188
189	df->iommufd = device->group->iommufd;
190	if (df->iommufd && vfio_device_is_noiommu(device) && device->open_count == 0) {
191		/*
192		 * Require no compat ioas to be assigned to proceed.  The basic
193		 * statement is that the user cannot have done something that
194		 * implies they expected translation to exist
195		 */
196		if (!capable(CAP_SYS_RAWIO) ||
197		    vfio_iommufd_device_has_compat_ioas(device, df->iommufd))
198			ret = -EPERM;
199		else
200			ret = 0;
201		goto out_put_kvm;
202	}
203
204	ret = vfio_df_open(df);
205	if (ret)
206		goto out_put_kvm;
207
208	if (df->iommufd && device->open_count == 1) {
209		ret = vfio_iommufd_compat_attach_ioas(device, df->iommufd);
210		if (ret)
211			goto out_close_device;
212	}
213
214	/*
215	 * Paired with smp_load_acquire() in vfio_device_fops::ioctl/
216	 * read/write/mmap and vfio_file_has_device_access()
 
217	 */
218	smp_store_release(&df->access_granted, true);
 
219
220	mutex_unlock(&device->dev_set->lock);
221	mutex_unlock(&device->group->group_lock);
222	return 0;
223
224out_close_device:
225	vfio_df_close(df);
226out_put_kvm:
227	df->iommufd = NULL;
228	if (device->open_count == 0)
229		vfio_device_put_kvm(device);
230	mutex_unlock(&device->dev_set->lock);
231out_unlock:
232	mutex_unlock(&device->group->group_lock);
233	return ret;
234}
235
236void vfio_df_group_close(struct vfio_device_file *df)
237{
238	struct vfio_device *device = df->device;
239
240	mutex_lock(&device->group->group_lock);
241	mutex_lock(&device->dev_set->lock);
242
243	vfio_df_close(df);
244	df->iommufd = NULL;
245
246	if (device->open_count == 0)
247		vfio_device_put_kvm(device);
248
249	mutex_unlock(&device->dev_set->lock);
250	mutex_unlock(&device->group->group_lock);
251}
252
253static struct file *vfio_device_open_file(struct vfio_device *device)
254{
255	struct vfio_device_file *df;
256	struct file *filep;
257	int ret;
258
259	df = vfio_allocate_device_file(device);
260	if (IS_ERR(df)) {
261		ret = PTR_ERR(df);
262		goto err_out;
263	}
264
265	df->group = device->group;
266
267	ret = vfio_df_group_open(df);
268	if (ret)
269		goto err_free;
270
271	/*
272	 * We can't use anon_inode_getfd() because we need to modify
273	 * the f_mode flags directly to allow more than just ioctls
274	 */
275	filep = anon_inode_getfile("[vfio-device]", &vfio_device_fops,
276				   df, O_RDWR);
277	if (IS_ERR(filep)) {
278		ret = PTR_ERR(filep);
279		goto err_close_device;
280	}
281
282	/*
283	 * TODO: add an anon_inode interface to do this.
284	 * Appears to be missing by lack of need rather than
285	 * explicitly prevented.  Now there's need.
286	 */
287	filep->f_mode |= (FMODE_PREAD | FMODE_PWRITE);
288
289	if (device->group->type == VFIO_NO_IOMMU)
290		dev_warn(device->dev, "vfio-noiommu device opened by user "
291			 "(%s:%d)\n", current->comm, task_pid_nr(current));
292	/*
293	 * On success the ref of device is moved to the file and
294	 * put in vfio_device_fops_release()
295	 */
296	return filep;
297
298err_close_device:
299	vfio_df_group_close(df);
300err_free:
301	kfree(df);
302err_out:
303	return ERR_PTR(ret);
304}
305
306static int vfio_group_ioctl_get_device_fd(struct vfio_group *group,
307					  char __user *arg)
308{
309	struct vfio_device *device;
310	struct file *filep;
311	char *buf;
312	int fdno;
313	int ret;
314
315	buf = strndup_user(arg, PAGE_SIZE);
316	if (IS_ERR(buf))
317		return PTR_ERR(buf);
318
319	device = vfio_device_get_from_name(group, buf);
320	kfree(buf);
321	if (IS_ERR(device))
322		return PTR_ERR(device);
323
324	fdno = get_unused_fd_flags(O_CLOEXEC);
325	if (fdno < 0) {
326		ret = fdno;
327		goto err_put_device;
328	}
329
330	filep = vfio_device_open_file(device);
331	if (IS_ERR(filep)) {
332		ret = PTR_ERR(filep);
333		goto err_put_fdno;
334	}
335
336	fd_install(fdno, filep);
337	return fdno;
338
339err_put_fdno:
340	put_unused_fd(fdno);
341err_put_device:
342	vfio_device_put_registration(device);
343	return ret;
344}
345
346static int vfio_group_ioctl_get_status(struct vfio_group *group,
347				       struct vfio_group_status __user *arg)
348{
349	unsigned long minsz = offsetofend(struct vfio_group_status, flags);
350	struct vfio_group_status status;
351
352	if (copy_from_user(&status, arg, minsz))
353		return -EFAULT;
354
355	if (status.argsz < minsz)
356		return -EINVAL;
357
358	status.flags = 0;
359
360	mutex_lock(&group->group_lock);
361	if (!group->iommu_group) {
362		mutex_unlock(&group->group_lock);
363		return -ENODEV;
364	}
365
366	/*
367	 * With the container FD the iommu_group_claim_dma_owner() is done
368	 * during SET_CONTAINER but for IOMMFD this is done during
369	 * VFIO_GROUP_GET_DEVICE_FD. Meaning that with iommufd
370	 * VFIO_GROUP_FLAGS_VIABLE could be set but GET_DEVICE_FD will fail due
371	 * to viability.
372	 */
373	if (vfio_group_has_iommu(group))
374		status.flags |= VFIO_GROUP_FLAGS_CONTAINER_SET |
375				VFIO_GROUP_FLAGS_VIABLE;
376	else if (!iommu_group_dma_owner_claimed(group->iommu_group))
377		status.flags |= VFIO_GROUP_FLAGS_VIABLE;
378	mutex_unlock(&group->group_lock);
379
380	if (copy_to_user(arg, &status, minsz))
381		return -EFAULT;
382	return 0;
383}
384
385static long vfio_group_fops_unl_ioctl(struct file *filep,
386				      unsigned int cmd, unsigned long arg)
387{
388	struct vfio_group *group = filep->private_data;
389	void __user *uarg = (void __user *)arg;
390
391	switch (cmd) {
392	case VFIO_GROUP_GET_DEVICE_FD:
393		return vfio_group_ioctl_get_device_fd(group, uarg);
394	case VFIO_GROUP_GET_STATUS:
395		return vfio_group_ioctl_get_status(group, uarg);
396	case VFIO_GROUP_SET_CONTAINER:
397		return vfio_group_ioctl_set_container(group, uarg);
398	case VFIO_GROUP_UNSET_CONTAINER:
399		return vfio_group_ioctl_unset_container(group);
400	default:
401		return -ENOTTY;
402	}
403}
404
405int vfio_device_block_group(struct vfio_device *device)
406{
407	struct vfio_group *group = device->group;
408	int ret = 0;
409
410	mutex_lock(&group->group_lock);
411	if (group->opened_file) {
412		ret = -EBUSY;
413		goto out_unlock;
414	}
415
416	group->cdev_device_open_cnt++;
417
418out_unlock:
419	mutex_unlock(&group->group_lock);
420	return ret;
421}
422
423void vfio_device_unblock_group(struct vfio_device *device)
424{
425	struct vfio_group *group = device->group;
426
427	mutex_lock(&group->group_lock);
428	group->cdev_device_open_cnt--;
429	mutex_unlock(&group->group_lock);
430}
431
432static int vfio_group_fops_open(struct inode *inode, struct file *filep)
433{
434	struct vfio_group *group =
435		container_of(inode->i_cdev, struct vfio_group, cdev);
436	int ret;
437
438	mutex_lock(&group->group_lock);
439
440	/*
441	 * drivers can be zero if this races with vfio_device_remove_group(), it
442	 * will be stable at 0 under the group rwsem
443	 */
444	if (refcount_read(&group->drivers) == 0) {
445		ret = -ENODEV;
446		goto out_unlock;
447	}
448
449	if (group->type == VFIO_NO_IOMMU && !capable(CAP_SYS_RAWIO)) {
450		ret = -EPERM;
451		goto out_unlock;
452	}
453
454	if (group->cdev_device_open_cnt) {
455		ret = -EBUSY;
456		goto out_unlock;
457	}
458
459	/*
460	 * Do we need multiple instances of the group open?  Seems not.
461	 */
462	if (group->opened_file) {
463		ret = -EBUSY;
464		goto out_unlock;
465	}
466	group->opened_file = filep;
467	filep->private_data = group;
468	ret = 0;
469out_unlock:
470	mutex_unlock(&group->group_lock);
471	return ret;
472}
473
474static int vfio_group_fops_release(struct inode *inode, struct file *filep)
475{
476	struct vfio_group *group = filep->private_data;
477
478	filep->private_data = NULL;
479
480	mutex_lock(&group->group_lock);
481	/*
482	 * Device FDs hold a group file reference, therefore the group release
483	 * is only called when there are no open devices.
484	 */
485	WARN_ON(group->notifier.head);
486	if (group->container)
487		vfio_group_detach_container(group);
488	if (group->iommufd) {
489		iommufd_ctx_put(group->iommufd);
490		group->iommufd = NULL;
491	}
492	group->opened_file = NULL;
493	mutex_unlock(&group->group_lock);
494	return 0;
495}
496
497static const struct file_operations vfio_group_fops = {
498	.owner		= THIS_MODULE,
499	.unlocked_ioctl	= vfio_group_fops_unl_ioctl,
500	.compat_ioctl	= compat_ptr_ioctl,
501	.open		= vfio_group_fops_open,
502	.release	= vfio_group_fops_release,
503};
504
505/*
506 * Group objects - create, release, get, put, search
507 */
508static struct vfio_group *
509vfio_group_find_from_iommu(struct iommu_group *iommu_group)
510{
511	struct vfio_group *group;
512
513	lockdep_assert_held(&vfio.group_lock);
514
515	/*
516	 * group->iommu_group from the vfio.group_list cannot be NULL
517	 * under the vfio.group_lock.
518	 */
519	list_for_each_entry(group, &vfio.group_list, vfio_next) {
520		if (group->iommu_group == iommu_group)
521			return group;
522	}
523	return NULL;
524}
525
526static void vfio_group_release(struct device *dev)
527{
528	struct vfio_group *group = container_of(dev, struct vfio_group, dev);
529
530	mutex_destroy(&group->device_lock);
531	mutex_destroy(&group->group_lock);
532	WARN_ON(group->iommu_group);
533	WARN_ON(group->cdev_device_open_cnt);
534	ida_free(&vfio.group_ida, MINOR(group->dev.devt));
535	kfree(group);
536}
537
538static struct vfio_group *vfio_group_alloc(struct iommu_group *iommu_group,
539					   enum vfio_group_type type)
540{
541	struct vfio_group *group;
542	int minor;
543
544	group = kzalloc(sizeof(*group), GFP_KERNEL);
545	if (!group)
546		return ERR_PTR(-ENOMEM);
547
548	minor = ida_alloc_max(&vfio.group_ida, MINORMASK, GFP_KERNEL);
549	if (minor < 0) {
550		kfree(group);
551		return ERR_PTR(minor);
552	}
553
554	device_initialize(&group->dev);
555	group->dev.devt = MKDEV(MAJOR(vfio.group_devt), minor);
556	group->dev.class = vfio.class;
557	group->dev.release = vfio_group_release;
558	cdev_init(&group->cdev, &vfio_group_fops);
559	group->cdev.owner = THIS_MODULE;
560
561	refcount_set(&group->drivers, 1);
562	mutex_init(&group->group_lock);
563	spin_lock_init(&group->kvm_ref_lock);
564	INIT_LIST_HEAD(&group->device_list);
565	mutex_init(&group->device_lock);
566	group->iommu_group = iommu_group;
567	/* put in vfio_group_release() */
568	iommu_group_ref_get(iommu_group);
569	group->type = type;
570	BLOCKING_INIT_NOTIFIER_HEAD(&group->notifier);
571
572	return group;
573}
574
575static struct vfio_group *vfio_create_group(struct iommu_group *iommu_group,
576		enum vfio_group_type type)
577{
578	struct vfio_group *group;
579	struct vfio_group *ret;
580	int err;
581
582	lockdep_assert_held(&vfio.group_lock);
583
584	group = vfio_group_alloc(iommu_group, type);
585	if (IS_ERR(group))
586		return group;
587
588	err = dev_set_name(&group->dev, "%s%d",
589			   group->type == VFIO_NO_IOMMU ? "noiommu-" : "",
590			   iommu_group_id(iommu_group));
591	if (err) {
592		ret = ERR_PTR(err);
593		goto err_put;
594	}
595
596	err = cdev_device_add(&group->cdev, &group->dev);
597	if (err) {
598		ret = ERR_PTR(err);
599		goto err_put;
600	}
601
602	list_add(&group->vfio_next, &vfio.group_list);
603
604	return group;
605
606err_put:
607	put_device(&group->dev);
608	return ret;
609}
610
611static struct vfio_group *vfio_noiommu_group_alloc(struct device *dev,
612		enum vfio_group_type type)
613{
614	struct iommu_group *iommu_group;
615	struct vfio_group *group;
616	int ret;
617
618	iommu_group = iommu_group_alloc();
619	if (IS_ERR(iommu_group))
620		return ERR_CAST(iommu_group);
621
622	ret = iommu_group_set_name(iommu_group, "vfio-noiommu");
623	if (ret)
624		goto out_put_group;
625	ret = iommu_group_add_device(iommu_group, dev);
626	if (ret)
627		goto out_put_group;
628
629	mutex_lock(&vfio.group_lock);
630	group = vfio_create_group(iommu_group, type);
631	mutex_unlock(&vfio.group_lock);
632	if (IS_ERR(group)) {
633		ret = PTR_ERR(group);
634		goto out_remove_device;
635	}
636	iommu_group_put(iommu_group);
637	return group;
638
639out_remove_device:
640	iommu_group_remove_device(dev);
641out_put_group:
642	iommu_group_put(iommu_group);
643	return ERR_PTR(ret);
644}
645
646static bool vfio_group_has_device(struct vfio_group *group, struct device *dev)
647{
648	struct vfio_device *device;
649
650	mutex_lock(&group->device_lock);
651	list_for_each_entry(device, &group->device_list, group_next) {
652		if (device->dev == dev) {
653			mutex_unlock(&group->device_lock);
654			return true;
655		}
656	}
657	mutex_unlock(&group->device_lock);
658	return false;
659}
660
661static struct vfio_group *vfio_group_find_or_alloc(struct device *dev)
662{
663	struct iommu_group *iommu_group;
664	struct vfio_group *group;
665
666	iommu_group = iommu_group_get(dev);
667	if (!iommu_group && vfio_noiommu) {
668		/*
669		 * With noiommu enabled, create an IOMMU group for devices that
670		 * don't already have one, implying no IOMMU hardware/driver
671		 * exists.  Taint the kernel because we're about to give a DMA
672		 * capable device to a user without IOMMU protection.
673		 */
674		group = vfio_noiommu_group_alloc(dev, VFIO_NO_IOMMU);
675		if (!IS_ERR(group)) {
676			add_taint(TAINT_USER, LOCKDEP_STILL_OK);
677			dev_warn(dev, "Adding kernel taint for vfio-noiommu group on device\n");
678		}
679		return group;
680	}
681
682	if (!iommu_group)
683		return ERR_PTR(-EINVAL);
684
 
 
 
 
 
 
 
 
 
 
685	mutex_lock(&vfio.group_lock);
686	group = vfio_group_find_from_iommu(iommu_group);
687	if (group) {
688		if (WARN_ON(vfio_group_has_device(group, dev)))
689			group = ERR_PTR(-EINVAL);
690		else
691			refcount_inc(&group->drivers);
692	} else {
693		group = vfio_create_group(iommu_group, VFIO_IOMMU);
694	}
695	mutex_unlock(&vfio.group_lock);
696
697	/* The vfio_group holds a reference to the iommu_group */
698	iommu_group_put(iommu_group);
699	return group;
700}
701
702int vfio_device_set_group(struct vfio_device *device,
703			  enum vfio_group_type type)
704{
705	struct vfio_group *group;
706
707	if (type == VFIO_IOMMU)
708		group = vfio_group_find_or_alloc(device->dev);
709	else
710		group = vfio_noiommu_group_alloc(device->dev, type);
711
712	if (IS_ERR(group))
713		return PTR_ERR(group);
714
715	/* Our reference on group is moved to the device */
716	device->group = group;
717	return 0;
718}
719
720void vfio_device_remove_group(struct vfio_device *device)
721{
722	struct vfio_group *group = device->group;
723	struct iommu_group *iommu_group;
724
725	if (group->type == VFIO_NO_IOMMU || group->type == VFIO_EMULATED_IOMMU)
726		iommu_group_remove_device(device->dev);
727
728	/* Pairs with vfio_create_group() / vfio_group_get_from_iommu() */
729	if (!refcount_dec_and_mutex_lock(&group->drivers, &vfio.group_lock))
730		return;
731	list_del(&group->vfio_next);
732
733	/*
734	 * We could concurrently probe another driver in the group that might
735	 * race vfio_device_remove_group() with vfio_get_group(), so we have to
736	 * ensure that the sysfs is all cleaned up under lock otherwise the
737	 * cdev_device_add() will fail due to the name aready existing.
738	 */
739	cdev_device_del(&group->cdev, &group->dev);
740
741	mutex_lock(&group->group_lock);
742	/*
743	 * These data structures all have paired operations that can only be
744	 * undone when the caller holds a live reference on the device. Since
745	 * all pairs must be undone these WARN_ON's indicate some caller did not
746	 * properly hold the group reference.
747	 */
748	WARN_ON(!list_empty(&group->device_list));
749	WARN_ON(group->notifier.head);
750
751	/*
752	 * Revoke all users of group->iommu_group. At this point we know there
753	 * are no devices active because we are unplugging the last one. Setting
754	 * iommu_group to NULL blocks all new users.
755	 */
756	if (group->container)
757		vfio_group_detach_container(group);
758	iommu_group = group->iommu_group;
759	group->iommu_group = NULL;
760	mutex_unlock(&group->group_lock);
761	mutex_unlock(&vfio.group_lock);
762
763	iommu_group_put(iommu_group);
764	put_device(&group->dev);
765}
766
767void vfio_device_group_register(struct vfio_device *device)
768{
769	mutex_lock(&device->group->device_lock);
770	list_add(&device->group_next, &device->group->device_list);
771	mutex_unlock(&device->group->device_lock);
772}
773
774void vfio_device_group_unregister(struct vfio_device *device)
775{
776	mutex_lock(&device->group->device_lock);
777	list_del(&device->group_next);
778	mutex_unlock(&device->group->device_lock);
779}
780
781int vfio_device_group_use_iommu(struct vfio_device *device)
782{
783	struct vfio_group *group = device->group;
784	int ret = 0;
785
786	lockdep_assert_held(&group->group_lock);
787
788	if (WARN_ON(!group->container))
789		return -EINVAL;
790
791	ret = vfio_group_use_container(group);
792	if (ret)
793		return ret;
794	vfio_device_container_register(device);
795	return 0;
796}
797
798void vfio_device_group_unuse_iommu(struct vfio_device *device)
799{
800	struct vfio_group *group = device->group;
801
802	lockdep_assert_held(&group->group_lock);
803
804	if (WARN_ON(!group->container))
805		return;
806
807	vfio_device_container_unregister(device);
808	vfio_group_unuse_container(group);
809}
810
811bool vfio_device_has_container(struct vfio_device *device)
812{
813	return device->group->container;
814}
815
816struct vfio_group *vfio_group_from_file(struct file *file)
817{
818	struct vfio_group *group = file->private_data;
819
820	if (file->f_op != &vfio_group_fops)
821		return NULL;
822	return group;
823}
824
825/**
826 * vfio_file_iommu_group - Return the struct iommu_group for the vfio group file
827 * @file: VFIO group file
828 *
829 * The returned iommu_group is valid as long as a ref is held on the file. This
830 * returns a reference on the group. This function is deprecated, only the SPAPR
831 * path in kvm should call it.
832 */
833struct iommu_group *vfio_file_iommu_group(struct file *file)
834{
835	struct vfio_group *group = vfio_group_from_file(file);
836	struct iommu_group *iommu_group = NULL;
837
838	if (!IS_ENABLED(CONFIG_SPAPR_TCE_IOMMU))
839		return NULL;
840
841	if (!group)
842		return NULL;
843
844	mutex_lock(&group->group_lock);
845	if (group->iommu_group) {
846		iommu_group = group->iommu_group;
847		iommu_group_ref_get(iommu_group);
848	}
849	mutex_unlock(&group->group_lock);
850	return iommu_group;
851}
852EXPORT_SYMBOL_GPL(vfio_file_iommu_group);
853
854/**
855 * vfio_file_is_group - True if the file is a vfio group file
856 * @file: VFIO group file
857 */
858bool vfio_file_is_group(struct file *file)
859{
860	return vfio_group_from_file(file);
861}
862EXPORT_SYMBOL_GPL(vfio_file_is_group);
863
864bool vfio_group_enforced_coherent(struct vfio_group *group)
 
 
 
 
 
 
 
 
 
865{
 
866	struct vfio_device *device;
867	bool ret = true;
868
 
 
 
869	/*
870	 * If the device does not have IOMMU_CAP_ENFORCE_CACHE_COHERENCY then
871	 * any domain later attached to it will also not support it. If the cap
872	 * is set then the iommu_domain eventually attached to the device/group
873	 * must use a domain with enforce_cache_coherency().
874	 */
875	mutex_lock(&group->device_lock);
876	list_for_each_entry(device, &group->device_list, group_next) {
877		if (!device_iommu_capable(device->dev,
878					  IOMMU_CAP_ENFORCE_CACHE_COHERENCY)) {
879			ret = false;
880			break;
881		}
882	}
883	mutex_unlock(&group->device_lock);
884	return ret;
885}
 
886
887void vfio_group_set_kvm(struct vfio_group *group, struct kvm *kvm)
 
 
 
 
 
 
 
 
888{
889	spin_lock(&group->kvm_ref_lock);
 
 
 
 
 
890	group->kvm = kvm;
891	spin_unlock(&group->kvm_ref_lock);
892}
 
893
894/**
895 * vfio_file_has_dev - True if the VFIO file is a handle for device
896 * @file: VFIO file to check
897 * @device: Device that must be part of the file
898 *
899 * Returns true if given file has permission to manipulate the given device.
900 */
901bool vfio_file_has_dev(struct file *file, struct vfio_device *device)
902{
903	struct vfio_group *group = vfio_group_from_file(file);
904
905	if (!group)
906		return false;
907
908	return group == device->group;
909}
910EXPORT_SYMBOL_GPL(vfio_file_has_dev);
911
912static char *vfio_devnode(const struct device *dev, umode_t *mode)
913{
914	return kasprintf(GFP_KERNEL, "vfio/%s", dev_name(dev));
915}
916
917int __init vfio_group_init(void)
918{
919	int ret;
920
921	ida_init(&vfio.group_ida);
922	mutex_init(&vfio.group_lock);
923	INIT_LIST_HEAD(&vfio.group_list);
924
925	ret = vfio_container_init();
926	if (ret)
927		return ret;
928
929	/* /dev/vfio/$GROUP */
930	vfio.class = class_create("vfio");
931	if (IS_ERR(vfio.class)) {
932		ret = PTR_ERR(vfio.class);
933		goto err_group_class;
934	}
935
936	vfio.class->devnode = vfio_devnode;
937
938	ret = alloc_chrdev_region(&vfio.group_devt, 0, MINORMASK + 1, "vfio");
939	if (ret)
940		goto err_alloc_chrdev;
941	return 0;
942
943err_alloc_chrdev:
944	class_destroy(vfio.class);
945	vfio.class = NULL;
946err_group_class:
947	vfio_container_cleanup();
948	return ret;
949}
950
951void vfio_group_cleanup(void)
952{
953	WARN_ON(!list_empty(&vfio.group_list));
954	ida_destroy(&vfio.group_ida);
955	unregister_chrdev_region(vfio.group_devt, MINORMASK + 1);
956	class_destroy(vfio.class);
957	vfio.class = NULL;
958	vfio_container_cleanup();
959}