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		else
198			ret = 0;
199		goto out_put_kvm;
200	}
201
202	ret = vfio_df_open(df);
203	if (ret)
204		goto out_put_kvm;
205
206	if (df->iommufd && device->open_count == 1) {
207		ret = vfio_iommufd_compat_attach_ioas(device, df->iommufd);
208		if (ret)
209			goto out_close_device;
210	}
211
212	/*
213	 * Paired with smp_load_acquire() in vfio_device_fops::ioctl/
214	 * read/write/mmap and vfio_file_has_device_access()
215	 */
216	smp_store_release(&df->access_granted, true);
217
218	mutex_unlock(&device->dev_set->lock);
219	mutex_unlock(&device->group->group_lock);
220	return 0;
221
222out_close_device:
223	vfio_df_close(df);
224out_put_kvm:
225	df->iommufd = NULL;
226	if (device->open_count == 0)
227		vfio_device_put_kvm(device);
228	mutex_unlock(&device->dev_set->lock);
229out_unlock:
230	mutex_unlock(&device->group->group_lock);
231	return ret;
232}
233
234void vfio_df_group_close(struct vfio_device_file *df)
235{
236	struct vfio_device *device = df->device;
237
238	mutex_lock(&device->group->group_lock);
239	mutex_lock(&device->dev_set->lock);
240
241	vfio_df_close(df);
242	df->iommufd = NULL;
243
244	if (device->open_count == 0)
245		vfio_device_put_kvm(device);
246
247	mutex_unlock(&device->dev_set->lock);
248	mutex_unlock(&device->group->group_lock);
249}
250
251static struct file *vfio_device_open_file(struct vfio_device *device)
252{
253	struct vfio_device_file *df;
254	struct file *filep;
255	int ret;
256
257	df = vfio_allocate_device_file(device);
258	if (IS_ERR(df)) {
259		ret = PTR_ERR(df);
260		goto err_out;
261	}
262
263	df->group = device->group;
264
265	ret = vfio_df_group_open(df);
266	if (ret)
267		goto err_free;
268
269	/*
270	 * We can't use anon_inode_getfd() because we need to modify
271	 * the f_mode flags directly to allow more than just ioctls
272	 */
273	filep = anon_inode_getfile("[vfio-device]", &vfio_device_fops,
274				   df, O_RDWR);
275	if (IS_ERR(filep)) {
276		ret = PTR_ERR(filep);
277		goto err_close_device;
278	}
279
280	/*
281	 * TODO: add an anon_inode interface to do this.
282	 * Appears to be missing by lack of need rather than
283	 * explicitly prevented.  Now there's need.
284	 */
285	filep->f_mode |= (FMODE_PREAD | FMODE_PWRITE);
286
287	/*
288	 * Use the pseudo fs inode on the device to link all mmaps
289	 * to the same address space, allowing us to unmap all vmas
290	 * associated to this device using unmap_mapping_range().
291	 */
292	filep->f_mapping = device->inode->i_mapping;
293
294	if (device->group->type == VFIO_NO_IOMMU)
295		dev_warn(device->dev, "vfio-noiommu device opened by user "
296			 "(%s:%d)\n", current->comm, task_pid_nr(current));
297	/*
298	 * On success the ref of device is moved to the file and
299	 * put in vfio_device_fops_release()
300	 */
301	return filep;
302
303err_close_device:
304	vfio_df_group_close(df);
305err_free:
306	kfree(df);
307err_out:
308	return ERR_PTR(ret);
309}
310
311static int vfio_group_ioctl_get_device_fd(struct vfio_group *group,
312					  char __user *arg)
313{
314	struct vfio_device *device;
315	struct file *filep;
316	char *buf;
317	int fdno;
318	int ret;
319
320	buf = strndup_user(arg, PAGE_SIZE);
321	if (IS_ERR(buf))
322		return PTR_ERR(buf);
323
324	device = vfio_device_get_from_name(group, buf);
325	kfree(buf);
326	if (IS_ERR(device))
327		return PTR_ERR(device);
328
329	fdno = get_unused_fd_flags(O_CLOEXEC);
330	if (fdno < 0) {
331		ret = fdno;
332		goto err_put_device;
333	}
334
335	filep = vfio_device_open_file(device);
336	if (IS_ERR(filep)) {
337		ret = PTR_ERR(filep);
338		goto err_put_fdno;
339	}
340
341	fd_install(fdno, filep);
342	return fdno;
343
344err_put_fdno:
345	put_unused_fd(fdno);
346err_put_device:
347	vfio_device_put_registration(device);
348	return ret;
349}
350
351static int vfio_group_ioctl_get_status(struct vfio_group *group,
352				       struct vfio_group_status __user *arg)
353{
354	unsigned long minsz = offsetofend(struct vfio_group_status, flags);
355	struct vfio_group_status status;
356
357	if (copy_from_user(&status, arg, minsz))
358		return -EFAULT;
359
360	if (status.argsz < minsz)
361		return -EINVAL;
362
363	status.flags = 0;
364
365	mutex_lock(&group->group_lock);
366	if (!group->iommu_group) {
367		mutex_unlock(&group->group_lock);
368		return -ENODEV;
369	}
370
371	/*
372	 * With the container FD the iommu_group_claim_dma_owner() is done
373	 * during SET_CONTAINER but for IOMMFD this is done during
374	 * VFIO_GROUP_GET_DEVICE_FD. Meaning that with iommufd
375	 * VFIO_GROUP_FLAGS_VIABLE could be set but GET_DEVICE_FD will fail due
376	 * to viability.
377	 */
378	if (vfio_group_has_iommu(group))
379		status.flags |= VFIO_GROUP_FLAGS_CONTAINER_SET |
380				VFIO_GROUP_FLAGS_VIABLE;
381	else if (!iommu_group_dma_owner_claimed(group->iommu_group))
382		status.flags |= VFIO_GROUP_FLAGS_VIABLE;
383	mutex_unlock(&group->group_lock);
384
385	if (copy_to_user(arg, &status, minsz))
386		return -EFAULT;
387	return 0;
388}
389
390static long vfio_group_fops_unl_ioctl(struct file *filep,
391				      unsigned int cmd, unsigned long arg)
392{
393	struct vfio_group *group = filep->private_data;
394	void __user *uarg = (void __user *)arg;
395
396	switch (cmd) {
397	case VFIO_GROUP_GET_DEVICE_FD:
398		return vfio_group_ioctl_get_device_fd(group, uarg);
399	case VFIO_GROUP_GET_STATUS:
400		return vfio_group_ioctl_get_status(group, uarg);
401	case VFIO_GROUP_SET_CONTAINER:
402		return vfio_group_ioctl_set_container(group, uarg);
403	case VFIO_GROUP_UNSET_CONTAINER:
404		return vfio_group_ioctl_unset_container(group);
405	default:
406		return -ENOTTY;
407	}
408}
409
410int vfio_device_block_group(struct vfio_device *device)
411{
412	struct vfio_group *group = device->group;
413	int ret = 0;
414
415	mutex_lock(&group->group_lock);
416	if (group->opened_file) {
417		ret = -EBUSY;
418		goto out_unlock;
419	}
420
421	group->cdev_device_open_cnt++;
422
423out_unlock:
424	mutex_unlock(&group->group_lock);
425	return ret;
426}
427
428void vfio_device_unblock_group(struct vfio_device *device)
429{
430	struct vfio_group *group = device->group;
431
432	mutex_lock(&group->group_lock);
433	group->cdev_device_open_cnt--;
434	mutex_unlock(&group->group_lock);
435}
436
437static int vfio_group_fops_open(struct inode *inode, struct file *filep)
438{
439	struct vfio_group *group =
440		container_of(inode->i_cdev, struct vfio_group, cdev);
441	int ret;
442
443	mutex_lock(&group->group_lock);
444
445	/*
446	 * drivers can be zero if this races with vfio_device_remove_group(), it
447	 * will be stable at 0 under the group rwsem
448	 */
449	if (refcount_read(&group->drivers) == 0) {
450		ret = -ENODEV;
451		goto out_unlock;
452	}
453
454	if (group->type == VFIO_NO_IOMMU && !capable(CAP_SYS_RAWIO)) {
455		ret = -EPERM;
456		goto out_unlock;
457	}
458
459	if (group->cdev_device_open_cnt) {
460		ret = -EBUSY;
461		goto out_unlock;
462	}
463
464	/*
465	 * Do we need multiple instances of the group open?  Seems not.
466	 */
467	if (group->opened_file) {
468		ret = -EBUSY;
469		goto out_unlock;
470	}
471	group->opened_file = filep;
472	filep->private_data = group;
473	ret = 0;
474out_unlock:
475	mutex_unlock(&group->group_lock);
476	return ret;
477}
478
479static int vfio_group_fops_release(struct inode *inode, struct file *filep)
480{
481	struct vfio_group *group = filep->private_data;
482
483	filep->private_data = NULL;
484
485	mutex_lock(&group->group_lock);
486	/*
487	 * Device FDs hold a group file reference, therefore the group release
488	 * is only called when there are no open devices.
489	 */
490	WARN_ON(group->notifier.head);
491	if (group->container)
492		vfio_group_detach_container(group);
493	if (group->iommufd) {
494		iommufd_ctx_put(group->iommufd);
495		group->iommufd = NULL;
496	}
497	group->opened_file = NULL;
498	mutex_unlock(&group->group_lock);
499	return 0;
500}
501
502static const struct file_operations vfio_group_fops = {
503	.owner		= THIS_MODULE,
504	.unlocked_ioctl	= vfio_group_fops_unl_ioctl,
505	.compat_ioctl	= compat_ptr_ioctl,
506	.open		= vfio_group_fops_open,
507	.release	= vfio_group_fops_release,
508};
509
510/*
511 * Group objects - create, release, get, put, search
512 */
513static struct vfio_group *
514vfio_group_find_from_iommu(struct iommu_group *iommu_group)
515{
516	struct vfio_group *group;
517
518	lockdep_assert_held(&vfio.group_lock);
519
520	/*
521	 * group->iommu_group from the vfio.group_list cannot be NULL
522	 * under the vfio.group_lock.
523	 */
524	list_for_each_entry(group, &vfio.group_list, vfio_next) {
525		if (group->iommu_group == iommu_group)
526			return group;
527	}
528	return NULL;
529}
530
531static void vfio_group_release(struct device *dev)
532{
533	struct vfio_group *group = container_of(dev, struct vfio_group, dev);
534
535	mutex_destroy(&group->device_lock);
536	mutex_destroy(&group->group_lock);
537	WARN_ON(group->iommu_group);
538	WARN_ON(group->cdev_device_open_cnt);
539	ida_free(&vfio.group_ida, MINOR(group->dev.devt));
540	kfree(group);
541}
542
543static struct vfio_group *vfio_group_alloc(struct iommu_group *iommu_group,
544					   enum vfio_group_type type)
545{
546	struct vfio_group *group;
547	int minor;
548
549	group = kzalloc(sizeof(*group), GFP_KERNEL);
550	if (!group)
551		return ERR_PTR(-ENOMEM);
552
553	minor = ida_alloc_max(&vfio.group_ida, MINORMASK, GFP_KERNEL);
554	if (minor < 0) {
555		kfree(group);
556		return ERR_PTR(minor);
557	}
558
559	device_initialize(&group->dev);
560	group->dev.devt = MKDEV(MAJOR(vfio.group_devt), minor);
561	group->dev.class = vfio.class;
562	group->dev.release = vfio_group_release;
563	cdev_init(&group->cdev, &vfio_group_fops);
564	group->cdev.owner = THIS_MODULE;
565
566	refcount_set(&group->drivers, 1);
567	mutex_init(&group->group_lock);
568	spin_lock_init(&group->kvm_ref_lock);
569	INIT_LIST_HEAD(&group->device_list);
570	mutex_init(&group->device_lock);
571	group->iommu_group = iommu_group;
572	/* put in vfio_group_release() */
573	iommu_group_ref_get(iommu_group);
574	group->type = type;
575	BLOCKING_INIT_NOTIFIER_HEAD(&group->notifier);
576
577	return group;
578}
579
580static struct vfio_group *vfio_create_group(struct iommu_group *iommu_group,
581		enum vfio_group_type type)
582{
583	struct vfio_group *group;
584	struct vfio_group *ret;
585	int err;
586
587	lockdep_assert_held(&vfio.group_lock);
588
589	group = vfio_group_alloc(iommu_group, type);
590	if (IS_ERR(group))
591		return group;
592
593	err = dev_set_name(&group->dev, "%s%d",
594			   group->type == VFIO_NO_IOMMU ? "noiommu-" : "",
595			   iommu_group_id(iommu_group));
596	if (err) {
597		ret = ERR_PTR(err);
598		goto err_put;
599	}
600
601	err = cdev_device_add(&group->cdev, &group->dev);
602	if (err) {
603		ret = ERR_PTR(err);
604		goto err_put;
605	}
606
607	list_add(&group->vfio_next, &vfio.group_list);
608
609	return group;
610
611err_put:
612	put_device(&group->dev);
613	return ret;
614}
615
616static struct vfio_group *vfio_noiommu_group_alloc(struct device *dev,
617		enum vfio_group_type type)
618{
619	struct iommu_group *iommu_group;
620	struct vfio_group *group;
621	int ret;
622
623	iommu_group = iommu_group_alloc();
624	if (IS_ERR(iommu_group))
625		return ERR_CAST(iommu_group);
626
627	ret = iommu_group_set_name(iommu_group, "vfio-noiommu");
628	if (ret)
629		goto out_put_group;
630	ret = iommu_group_add_device(iommu_group, dev);
631	if (ret)
632		goto out_put_group;
633
634	mutex_lock(&vfio.group_lock);
635	group = vfio_create_group(iommu_group, type);
636	mutex_unlock(&vfio.group_lock);
637	if (IS_ERR(group)) {
638		ret = PTR_ERR(group);
639		goto out_remove_device;
640	}
641	iommu_group_put(iommu_group);
642	return group;
643
644out_remove_device:
645	iommu_group_remove_device(dev);
646out_put_group:
647	iommu_group_put(iommu_group);
648	return ERR_PTR(ret);
649}
650
651static bool vfio_group_has_device(struct vfio_group *group, struct device *dev)
652{
653	struct vfio_device *device;
654
655	mutex_lock(&group->device_lock);
656	list_for_each_entry(device, &group->device_list, group_next) {
657		if (device->dev == dev) {
658			mutex_unlock(&group->device_lock);
659			return true;
660		}
661	}
662	mutex_unlock(&group->device_lock);
663	return false;
664}
665
666static struct vfio_group *vfio_group_find_or_alloc(struct device *dev)
667{
668	struct iommu_group *iommu_group;
669	struct vfio_group *group;
670
671	iommu_group = iommu_group_get(dev);
672	if (!iommu_group && vfio_noiommu) {
673		/*
674		 * With noiommu enabled, create an IOMMU group for devices that
675		 * don't already have one, implying no IOMMU hardware/driver
676		 * exists.  Taint the kernel because we're about to give a DMA
677		 * capable device to a user without IOMMU protection.
678		 */
679		group = vfio_noiommu_group_alloc(dev, VFIO_NO_IOMMU);
680		if (!IS_ERR(group)) {
681			add_taint(TAINT_USER, LOCKDEP_STILL_OK);
682			dev_warn(dev, "Adding kernel taint for vfio-noiommu group on device\n");
683		}
684		return group;
685	}
686
687	if (!iommu_group)
688		return ERR_PTR(-EINVAL);
689
 
 
 
 
 
 
 
 
 
 
690	mutex_lock(&vfio.group_lock);
691	group = vfio_group_find_from_iommu(iommu_group);
692	if (group) {
693		if (WARN_ON(vfio_group_has_device(group, dev)))
694			group = ERR_PTR(-EINVAL);
695		else
696			refcount_inc(&group->drivers);
697	} else {
698		group = vfio_create_group(iommu_group, VFIO_IOMMU);
699	}
700	mutex_unlock(&vfio.group_lock);
701
702	/* The vfio_group holds a reference to the iommu_group */
703	iommu_group_put(iommu_group);
704	return group;
705}
706
707int vfio_device_set_group(struct vfio_device *device,
708			  enum vfio_group_type type)
709{
710	struct vfio_group *group;
711
712	if (type == VFIO_IOMMU)
713		group = vfio_group_find_or_alloc(device->dev);
714	else
715		group = vfio_noiommu_group_alloc(device->dev, type);
716
717	if (IS_ERR(group))
718		return PTR_ERR(group);
719
720	/* Our reference on group is moved to the device */
721	device->group = group;
722	return 0;
723}
724
725void vfio_device_remove_group(struct vfio_device *device)
726{
727	struct vfio_group *group = device->group;
728	struct iommu_group *iommu_group;
729
730	if (group->type == VFIO_NO_IOMMU || group->type == VFIO_EMULATED_IOMMU)
731		iommu_group_remove_device(device->dev);
732
733	/* Pairs with vfio_create_group() / vfio_group_get_from_iommu() */
734	if (!refcount_dec_and_mutex_lock(&group->drivers, &vfio.group_lock))
735		return;
736	list_del(&group->vfio_next);
737
738	/*
739	 * We could concurrently probe another driver in the group that might
740	 * race vfio_device_remove_group() with vfio_get_group(), so we have to
741	 * ensure that the sysfs is all cleaned up under lock otherwise the
742	 * cdev_device_add() will fail due to the name aready existing.
743	 */
744	cdev_device_del(&group->cdev, &group->dev);
745
746	mutex_lock(&group->group_lock);
747	/*
748	 * These data structures all have paired operations that can only be
749	 * undone when the caller holds a live reference on the device. Since
750	 * all pairs must be undone these WARN_ON's indicate some caller did not
751	 * properly hold the group reference.
752	 */
753	WARN_ON(!list_empty(&group->device_list));
754	WARN_ON(group->notifier.head);
755
756	/*
757	 * Revoke all users of group->iommu_group. At this point we know there
758	 * are no devices active because we are unplugging the last one. Setting
759	 * iommu_group to NULL blocks all new users.
760	 */
761	if (group->container)
762		vfio_group_detach_container(group);
763	iommu_group = group->iommu_group;
764	group->iommu_group = NULL;
765	mutex_unlock(&group->group_lock);
766	mutex_unlock(&vfio.group_lock);
767
768	iommu_group_put(iommu_group);
769	put_device(&group->dev);
770}
771
772void vfio_device_group_register(struct vfio_device *device)
773{
774	mutex_lock(&device->group->device_lock);
775	list_add(&device->group_next, &device->group->device_list);
776	mutex_unlock(&device->group->device_lock);
777}
778
779void vfio_device_group_unregister(struct vfio_device *device)
780{
781	mutex_lock(&device->group->device_lock);
782	list_del(&device->group_next);
783	mutex_unlock(&device->group->device_lock);
784}
785
786int vfio_device_group_use_iommu(struct vfio_device *device)
787{
788	struct vfio_group *group = device->group;
789	int ret = 0;
790
791	lockdep_assert_held(&group->group_lock);
792
793	if (WARN_ON(!group->container))
794		return -EINVAL;
795
796	ret = vfio_group_use_container(group);
797	if (ret)
798		return ret;
799	vfio_device_container_register(device);
800	return 0;
801}
802
803void vfio_device_group_unuse_iommu(struct vfio_device *device)
804{
805	struct vfio_group *group = device->group;
806
807	lockdep_assert_held(&group->group_lock);
808
809	if (WARN_ON(!group->container))
810		return;
811
812	vfio_device_container_unregister(device);
813	vfio_group_unuse_container(group);
814}
815
816bool vfio_device_has_container(struct vfio_device *device)
817{
818	return device->group->container;
819}
820
821struct vfio_group *vfio_group_from_file(struct file *file)
822{
823	struct vfio_group *group = file->private_data;
824
825	if (file->f_op != &vfio_group_fops)
826		return NULL;
827	return group;
828}
829
830/**
831 * vfio_file_iommu_group - Return the struct iommu_group for the vfio group file
832 * @file: VFIO group file
833 *
834 * The returned iommu_group is valid as long as a ref is held on the file. This
835 * returns a reference on the group. This function is deprecated, only the SPAPR
836 * path in kvm should call it.
837 */
838struct iommu_group *vfio_file_iommu_group(struct file *file)
839{
840	struct vfio_group *group = vfio_group_from_file(file);
841	struct iommu_group *iommu_group = NULL;
842
843	if (!IS_ENABLED(CONFIG_SPAPR_TCE_IOMMU))
844		return NULL;
845
846	if (!group)
847		return NULL;
848
849	mutex_lock(&group->group_lock);
850	if (group->iommu_group) {
851		iommu_group = group->iommu_group;
852		iommu_group_ref_get(iommu_group);
853	}
854	mutex_unlock(&group->group_lock);
855	return iommu_group;
856}
857EXPORT_SYMBOL_GPL(vfio_file_iommu_group);
858
859/**
860 * vfio_file_is_group - True if the file is a vfio group file
861 * @file: VFIO group file
862 */
863bool vfio_file_is_group(struct file *file)
864{
865	return vfio_group_from_file(file);
866}
867EXPORT_SYMBOL_GPL(vfio_file_is_group);
868
869bool vfio_group_enforced_coherent(struct vfio_group *group)
 
 
 
 
 
 
 
 
 
870{
 
871	struct vfio_device *device;
872	bool ret = true;
873
 
 
 
874	/*
875	 * If the device does not have IOMMU_CAP_ENFORCE_CACHE_COHERENCY then
876	 * any domain later attached to it will also not support it. If the cap
877	 * is set then the iommu_domain eventually attached to the device/group
878	 * must use a domain with enforce_cache_coherency().
879	 */
880	mutex_lock(&group->device_lock);
881	list_for_each_entry(device, &group->device_list, group_next) {
882		if (!device_iommu_capable(device->dev,
883					  IOMMU_CAP_ENFORCE_CACHE_COHERENCY)) {
884			ret = false;
885			break;
886		}
887	}
888	mutex_unlock(&group->device_lock);
889	return ret;
890}
 
891
892void vfio_group_set_kvm(struct vfio_group *group, struct kvm *kvm)
 
 
 
 
 
 
 
 
893{
894	spin_lock(&group->kvm_ref_lock);
 
 
 
 
 
895	group->kvm = kvm;
896	spin_unlock(&group->kvm_ref_lock);
897}
 
898
899/**
900 * vfio_file_has_dev - True if the VFIO file is a handle for device
901 * @file: VFIO file to check
902 * @device: Device that must be part of the file
903 *
904 * Returns true if given file has permission to manipulate the given device.
905 */
906bool vfio_file_has_dev(struct file *file, struct vfio_device *device)
907{
908	struct vfio_group *group = vfio_group_from_file(file);
909
910	if (!group)
911		return false;
912
913	return group == device->group;
914}
915EXPORT_SYMBOL_GPL(vfio_file_has_dev);
916
917static char *vfio_devnode(const struct device *dev, umode_t *mode)
918{
919	return kasprintf(GFP_KERNEL, "vfio/%s", dev_name(dev));
920}
921
922int __init vfio_group_init(void)
923{
924	int ret;
925
926	ida_init(&vfio.group_ida);
927	mutex_init(&vfio.group_lock);
928	INIT_LIST_HEAD(&vfio.group_list);
929
930	ret = vfio_container_init();
931	if (ret)
932		return ret;
933
934	/* /dev/vfio/$GROUP */
935	vfio.class = class_create("vfio");
936	if (IS_ERR(vfio.class)) {
937		ret = PTR_ERR(vfio.class);
938		goto err_group_class;
939	}
940
941	vfio.class->devnode = vfio_devnode;
942
943	ret = alloc_chrdev_region(&vfio.group_devt, 0, MINORMASK + 1, "vfio");
944	if (ret)
945		goto err_alloc_chrdev;
946	return 0;
947
948err_alloc_chrdev:
949	class_destroy(vfio.class);
950	vfio.class = NULL;
951err_group_class:
952	vfio_container_cleanup();
953	return ret;
954}
955
956void vfio_group_cleanup(void)
957{
958	WARN_ON(!list_empty(&vfio.group_list));
959	ida_destroy(&vfio.group_ida);
960	unregister_chrdev_region(vfio.group_devt, MINORMASK + 1);
961	class_destroy(vfio.class);
962	vfio.class = NULL;
963	vfio_container_cleanup();
964}