Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 959 insertions, 0 deletions

diff --git a/drivers/vfio/group.c b/drivers/vfio/group.c
new file mode 100644
index 0000000000..610a429c61
--- /dev/null
+++ b/drivers/vfio/group.c
@@ -0,0 +1,959 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * VFIO core
+ *
+ * Copyright (C) 2012 Red Hat, Inc.  All rights reserved.
+ *     Author: Alex Williamson <alex.williamson@redhat.com>
+ *
+ * Derived from original vfio:
+ * Copyright 2010 Cisco Systems, Inc.  All rights reserved.
+ * Author: Tom Lyon, pugs@cisco.com
+ */
+
+#include <linux/vfio.h>
+#include <linux/iommufd.h>
+#include <linux/anon_inodes.h>
+#include "vfio.h"
+
+static struct vfio {
+	struct class			*class;
+	struct list_head		group_list;
+	struct mutex			group_lock; /* locks group_list */
+	struct ida			group_ida;
+	dev_t				group_devt;
+} vfio;
+
+static struct vfio_device *vfio_device_get_from_name(struct vfio_group *group,
+						     char *buf)
+{
+	struct vfio_device *it, *device = ERR_PTR(-ENODEV);
+
+	mutex_lock(&group->device_lock);
+	list_for_each_entry(it, &group->device_list, group_next) {
+		int ret;
+
+		if (it->ops->match) {
+			ret = it->ops->match(it, buf);
+			if (ret < 0) {
+				device = ERR_PTR(ret);
+				break;
+			}
+		} else {
+			ret = !strcmp(dev_name(it->dev), buf);
+		}
+
+		if (ret && vfio_device_try_get_registration(it)) {
+			device = it;
+			break;
+		}
+	}
+	mutex_unlock(&group->device_lock);
+
+	return device;
+}
+
+/*
+ * VFIO Group fd, /dev/vfio/$GROUP
+ */
+static bool vfio_group_has_iommu(struct vfio_group *group)
+{
+	lockdep_assert_held(&group->group_lock);
+	/*
+	 * There can only be users if there is a container, and if there is a
+	 * container there must be users.
+	 */
+	WARN_ON(!group->container != !group->container_users);
+
+	return group->container || group->iommufd;
+}
+
+/*
+ * VFIO_GROUP_UNSET_CONTAINER should fail if there are other users or
+ * if there was no container to unset.  Since the ioctl is called on
+ * the group, we know that still exists, therefore the only valid
+ * transition here is 1->0.
+ */
+static int vfio_group_ioctl_unset_container(struct vfio_group *group)
+{
+	int ret = 0;
+
+	mutex_lock(&group->group_lock);
+	if (!vfio_group_has_iommu(group)) {
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+	if (group->container) {
+		if (group->container_users != 1) {
+			ret = -EBUSY;
+			goto out_unlock;
+		}
+		vfio_group_detach_container(group);
+	}
+	if (group->iommufd) {
+		iommufd_ctx_put(group->iommufd);
+		group->iommufd = NULL;
+	}
+
+out_unlock:
+	mutex_unlock(&group->group_lock);
+	return ret;
+}
+
+static int vfio_group_ioctl_set_container(struct vfio_group *group,
+					  int __user *arg)
+{
+	struct vfio_container *container;
+	struct iommufd_ctx *iommufd;
+	struct fd f;
+	int ret;
+	int fd;
+
+	if (get_user(fd, arg))
+		return -EFAULT;
+
+	f = fdget(fd);
+	if (!f.file)
+		return -EBADF;
+
+	mutex_lock(&group->group_lock);
+	if (vfio_group_has_iommu(group)) {
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+	if (!group->iommu_group) {
+		ret = -ENODEV;
+		goto out_unlock;
+	}
+
+	container = vfio_container_from_file(f.file);
+	if (container) {
+		ret = vfio_container_attach_group(container, group);
+		goto out_unlock;
+	}
+
+	iommufd = iommufd_ctx_from_file(f.file);
+	if (!IS_ERR(iommufd)) {
+		if (IS_ENABLED(CONFIG_VFIO_NOIOMMU) &&
+		    group->type == VFIO_NO_IOMMU)
+			ret = iommufd_vfio_compat_set_no_iommu(iommufd);
+		else
+			ret = iommufd_vfio_compat_ioas_create(iommufd);
+
+		if (ret) {
+			iommufd_ctx_put(iommufd);
+			goto out_unlock;
+		}
+
+		group->iommufd = iommufd;
+		goto out_unlock;
+	}
+
+	/* The FD passed is not recognized. */
+	ret = -EBADFD;
+
+out_unlock:
+	mutex_unlock(&group->group_lock);
+	fdput(f);
+	return ret;
+}
+
+static void vfio_device_group_get_kvm_safe(struct vfio_device *device)
+{
+	spin_lock(&device->group->kvm_ref_lock);
+	vfio_device_get_kvm_safe(device, device->group->kvm);
+	spin_unlock(&device->group->kvm_ref_lock);
+}
+
+static int vfio_df_group_open(struct vfio_device_file *df)
+{
+	struct vfio_device *device = df->device;
+	int ret;
+
+	mutex_lock(&device->group->group_lock);
+	if (!vfio_group_has_iommu(device->group)) {
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+
+	mutex_lock(&device->dev_set->lock);
+
+	/*
+	 * Before the first device open, get the KVM pointer currently
+	 * associated with the group (if there is one) and obtain a reference
+	 * now that will be held until the open_count reaches 0 again.  Save
+	 * the pointer in the device for use by drivers.
+	 */
+	if (device->open_count == 0)
+		vfio_device_group_get_kvm_safe(device);
+
+	df->iommufd = device->group->iommufd;
+	if (df->iommufd && vfio_device_is_noiommu(device) && device->open_count == 0) {
+		/*
+		 * Require no compat ioas to be assigned to proceed.  The basic
+		 * statement is that the user cannot have done something that
+		 * implies they expected translation to exist
+		 */
+		if (!capable(CAP_SYS_RAWIO) ||
+		    vfio_iommufd_device_has_compat_ioas(device, df->iommufd))
+			ret = -EPERM;
+		else
+			ret = 0;
+		goto out_put_kvm;
+	}
+
+	ret = vfio_df_open(df);
+	if (ret)
+		goto out_put_kvm;
+
+	if (df->iommufd && device->open_count == 1) {
+		ret = vfio_iommufd_compat_attach_ioas(device, df->iommufd);
+		if (ret)
+			goto out_close_device;
+	}
+
+	/*
+	 * Paired with smp_load_acquire() in vfio_device_fops::ioctl/
+	 * read/write/mmap and vfio_file_has_device_access()
+	 */
+	smp_store_release(&df->access_granted, true);
+
+	mutex_unlock(&device->dev_set->lock);
+	mutex_unlock(&device->group->group_lock);
+	return 0;
+
+out_close_device:
+	vfio_df_close(df);
+out_put_kvm:
+	df->iommufd = NULL;
+	if (device->open_count == 0)
+		vfio_device_put_kvm(device);
+	mutex_unlock(&device->dev_set->lock);
+out_unlock:
+	mutex_unlock(&device->group->group_lock);
+	return ret;
+}
+
+void vfio_df_group_close(struct vfio_device_file *df)
+{
+	struct vfio_device *device = df->device;
+
+	mutex_lock(&device->group->group_lock);
+	mutex_lock(&device->dev_set->lock);
+
+	vfio_df_close(df);
+	df->iommufd = NULL;
+
+	if (device->open_count == 0)
+		vfio_device_put_kvm(device);
+
+	mutex_unlock(&device->dev_set->lock);
+	mutex_unlock(&device->group->group_lock);
+}
+
+static struct file *vfio_device_open_file(struct vfio_device *device)
+{
+	struct vfio_device_file *df;
+	struct file *filep;
+	int ret;
+
+	df = vfio_allocate_device_file(device);
+	if (IS_ERR(df)) {
+		ret = PTR_ERR(df);
+		goto err_out;
+	}
+
+	df->group = device->group;
+
+	ret = vfio_df_group_open(df);
+	if (ret)
+		goto err_free;
+
+	/*
+	 * We can't use anon_inode_getfd() because we need to modify
+	 * the f_mode flags directly to allow more than just ioctls
+	 */
+	filep = anon_inode_getfile("[vfio-device]", &vfio_device_fops,
+				   df, O_RDWR);
+	if (IS_ERR(filep)) {
+		ret = PTR_ERR(filep);
+		goto err_close_device;
+	}
+
+	/*
+	 * TODO: add an anon_inode interface to do this.
+	 * Appears to be missing by lack of need rather than
+	 * explicitly prevented.  Now there's need.
+	 */
+	filep->f_mode |= (FMODE_PREAD | FMODE_PWRITE);
+
+	if (device->group->type == VFIO_NO_IOMMU)
+		dev_warn(device->dev, "vfio-noiommu device opened by user "
+			 "(%s:%d)\n", current->comm, task_pid_nr(current));
+	/*
+	 * On success the ref of device is moved to the file and
+	 * put in vfio_device_fops_release()
+	 */
+	return filep;
+
+err_close_device:
+	vfio_df_group_close(df);
+err_free:
+	kfree(df);
+err_out:
+	return ERR_PTR(ret);
+}
+
+static int vfio_group_ioctl_get_device_fd(struct vfio_group *group,
+					  char __user *arg)
+{
+	struct vfio_device *device;
+	struct file *filep;
+	char *buf;
+	int fdno;
+	int ret;
+
+	buf = strndup_user(arg, PAGE_SIZE);
+	if (IS_ERR(buf))
+		return PTR_ERR(buf);
+
+	device = vfio_device_get_from_name(group, buf);
+	kfree(buf);
+	if (IS_ERR(device))
+		return PTR_ERR(device);
+
+	fdno = get_unused_fd_flags(O_CLOEXEC);
+	if (fdno < 0) {
+		ret = fdno;
+		goto err_put_device;
+	}
+
+	filep = vfio_device_open_file(device);
+	if (IS_ERR(filep)) {
+		ret = PTR_ERR(filep);
+		goto err_put_fdno;
+	}
+
+	fd_install(fdno, filep);
+	return fdno;
+
+err_put_fdno:
+	put_unused_fd(fdno);
+err_put_device:
+	vfio_device_put_registration(device);
+	return ret;
+}
+
+static int vfio_group_ioctl_get_status(struct vfio_group *group,
+				       struct vfio_group_status __user *arg)
+{
+	unsigned long minsz = offsetofend(struct vfio_group_status, flags);
+	struct vfio_group_status status;
+
+	if (copy_from_user(&status, arg, minsz))
+		return -EFAULT;
+
+	if (status.argsz < minsz)
+		return -EINVAL;
+
+	status.flags = 0;
+
+	mutex_lock(&group->group_lock);
+	if (!group->iommu_group) {
+		mutex_unlock(&group->group_lock);
+		return -ENODEV;
+	}
+
+	/*
+	 * With the container FD the iommu_group_claim_dma_owner() is done
+	 * during SET_CONTAINER but for IOMMFD this is done during
+	 * VFIO_GROUP_GET_DEVICE_FD. Meaning that with iommufd
+	 * VFIO_GROUP_FLAGS_VIABLE could be set but GET_DEVICE_FD will fail due
+	 * to viability.
+	 */
+	if (vfio_group_has_iommu(group))
+		status.flags |= VFIO_GROUP_FLAGS_CONTAINER_SET |
+				VFIO_GROUP_FLAGS_VIABLE;
+	else if (!iommu_group_dma_owner_claimed(group->iommu_group))
+		status.flags |= VFIO_GROUP_FLAGS_VIABLE;
+	mutex_unlock(&group->group_lock);
+
+	if (copy_to_user(arg, &status, minsz))
+		return -EFAULT;
+	return 0;
+}
+
+static long vfio_group_fops_unl_ioctl(struct file *filep,
+				      unsigned int cmd, unsigned long arg)
+{
+	struct vfio_group *group = filep->private_data;
+	void __user *uarg = (void __user *)arg;
+
+	switch (cmd) {
+	case VFIO_GROUP_GET_DEVICE_FD:
+		return vfio_group_ioctl_get_device_fd(group, uarg);
+	case VFIO_GROUP_GET_STATUS:
+		return vfio_group_ioctl_get_status(group, uarg);
+	case VFIO_GROUP_SET_CONTAINER:
+		return vfio_group_ioctl_set_container(group, uarg);
+	case VFIO_GROUP_UNSET_CONTAINER:
+		return vfio_group_ioctl_unset_container(group);
+	default:
+		return -ENOTTY;
+	}
+}
+
+int vfio_device_block_group(struct vfio_device *device)
+{
+	struct vfio_group *group = device->group;
+	int ret = 0;
+
+	mutex_lock(&group->group_lock);
+	if (group->opened_file) {
+		ret = -EBUSY;
+		goto out_unlock;
+	}
+
+	group->cdev_device_open_cnt++;
+
+out_unlock:
+	mutex_unlock(&group->group_lock);
+	return ret;
+}
+
+void vfio_device_unblock_group(struct vfio_device *device)
+{
+	struct vfio_group *group = device->group;
+
+	mutex_lock(&group->group_lock);
+	group->cdev_device_open_cnt--;
+	mutex_unlock(&group->group_lock);
+}
+
+static int vfio_group_fops_open(struct inode *inode, struct file *filep)
+{
+	struct vfio_group *group =
+		container_of(inode->i_cdev, struct vfio_group, cdev);
+	int ret;
+
+	mutex_lock(&group->group_lock);
+
+	/*
+	 * drivers can be zero if this races with vfio_device_remove_group(), it
+	 * will be stable at 0 under the group rwsem
+	 */
+	if (refcount_read(&group->drivers) == 0) {
+		ret = -ENODEV;
+		goto out_unlock;
+	}
+
+	if (group->type == VFIO_NO_IOMMU && !capable(CAP_SYS_RAWIO)) {
+		ret = -EPERM;
+		goto out_unlock;
+	}
+
+	if (group->cdev_device_open_cnt) {
+		ret = -EBUSY;
+		goto out_unlock;
+	}
+
+	/*
+	 * Do we need multiple instances of the group open?  Seems not.
+	 */
+	if (group->opened_file) {
+		ret = -EBUSY;
+		goto out_unlock;
+	}
+	group->opened_file = filep;
+	filep->private_data = group;
+	ret = 0;
+out_unlock:
+	mutex_unlock(&group->group_lock);
+	return ret;
+}
+
+static int vfio_group_fops_release(struct inode *inode, struct file *filep)
+{
+	struct vfio_group *group = filep->private_data;
+
+	filep->private_data = NULL;
+
+	mutex_lock(&group->group_lock);
+	/*
+	 * Device FDs hold a group file reference, therefore the group release
+	 * is only called when there are no open devices.
+	 */
+	WARN_ON(group->notifier.head);
+	if (group->container)
+		vfio_group_detach_container(group);
+	if (group->iommufd) {
+		iommufd_ctx_put(group->iommufd);
+		group->iommufd = NULL;
+	}
+	group->opened_file = NULL;
+	mutex_unlock(&group->group_lock);
+	return 0;
+}
+
+static const struct file_operations vfio_group_fops = {
+	.owner		= THIS_MODULE,
+	.unlocked_ioctl	= vfio_group_fops_unl_ioctl,
+	.compat_ioctl	= compat_ptr_ioctl,
+	.open		= vfio_group_fops_open,
+	.release	= vfio_group_fops_release,
+};
+
+/*
+ * Group objects - create, release, get, put, search
+ */
+static struct vfio_group *
+vfio_group_find_from_iommu(struct iommu_group *iommu_group)
+{
+	struct vfio_group *group;
+
+	lockdep_assert_held(&vfio.group_lock);
+
+	/*
+	 * group->iommu_group from the vfio.group_list cannot be NULL
+	 * under the vfio.group_lock.
+	 */
+	list_for_each_entry(group, &vfio.group_list, vfio_next) {
+		if (group->iommu_group == iommu_group)
+			return group;
+	}
+	return NULL;
+}
+
+static void vfio_group_release(struct device *dev)
+{
+	struct vfio_group *group = container_of(dev, struct vfio_group, dev);
+
+	mutex_destroy(&group->device_lock);
+	mutex_destroy(&group->group_lock);
+	WARN_ON(group->iommu_group);
+	WARN_ON(group->cdev_device_open_cnt);
+	ida_free(&vfio.group_ida, MINOR(group->dev.devt));
+	kfree(group);
+}
+
+static struct vfio_group *vfio_group_alloc(struct iommu_group *iommu_group,
+					   enum vfio_group_type type)
+{
+	struct vfio_group *group;
+	int minor;
+
+	group = kzalloc(sizeof(*group), GFP_KERNEL);
+	if (!group)
+		return ERR_PTR(-ENOMEM);
+
+	minor = ida_alloc_max(&vfio.group_ida, MINORMASK, GFP_KERNEL);
+	if (minor < 0) {
+		kfree(group);
+		return ERR_PTR(minor);
+	}
+
+	device_initialize(&group->dev);
+	group->dev.devt = MKDEV(MAJOR(vfio.group_devt), minor);
+	group->dev.class = vfio.class;
+	group->dev.release = vfio_group_release;
+	cdev_init(&group->cdev, &vfio_group_fops);
+	group->cdev.owner = THIS_MODULE;
+
+	refcount_set(&group->drivers, 1);
+	mutex_init(&group->group_lock);
+	spin_lock_init(&group->kvm_ref_lock);
+	INIT_LIST_HEAD(&group->device_list);
+	mutex_init(&group->device_lock);
+	group->iommu_group = iommu_group;
+	/* put in vfio_group_release() */
+	iommu_group_ref_get(iommu_group);
+	group->type = type;
+	BLOCKING_INIT_NOTIFIER_HEAD(&group->notifier);
+
+	return group;
+}
+
+static struct vfio_group *vfio_create_group(struct iommu_group *iommu_group,
+		enum vfio_group_type type)
+{
+	struct vfio_group *group;
+	struct vfio_group *ret;
+	int err;
+
+	lockdep_assert_held(&vfio.group_lock);
+
+	group = vfio_group_alloc(iommu_group, type);
+	if (IS_ERR(group))
+		return group;
+
+	err = dev_set_name(&group->dev, "%s%d",
+			   group->type == VFIO_NO_IOMMU ? "noiommu-" : "",
+			   iommu_group_id(iommu_group));
+	if (err) {
+		ret = ERR_PTR(err);
+		goto err_put;
+	}
+
+	err = cdev_device_add(&group->cdev, &group->dev);
+	if (err) {
+		ret = ERR_PTR(err);
+		goto err_put;
+	}
+
+	list_add(&group->vfio_next, &vfio.group_list);
+
+	return group;
+
+err_put:
+	put_device(&group->dev);
+	return ret;
+}
+
+static struct vfio_group *vfio_noiommu_group_alloc(struct device *dev,
+		enum vfio_group_type type)
+{
+	struct iommu_group *iommu_group;
+	struct vfio_group *group;
+	int ret;
+
+	iommu_group = iommu_group_alloc();
+	if (IS_ERR(iommu_group))
+		return ERR_CAST(iommu_group);
+
+	ret = iommu_group_set_name(iommu_group, "vfio-noiommu");
+	if (ret)
+		goto out_put_group;
+	ret = iommu_group_add_device(iommu_group, dev);
+	if (ret)
+		goto out_put_group;
+
+	mutex_lock(&vfio.group_lock);
+	group = vfio_create_group(iommu_group, type);
+	mutex_unlock(&vfio.group_lock);
+	if (IS_ERR(group)) {
+		ret = PTR_ERR(group);
+		goto out_remove_device;
+	}
+	iommu_group_put(iommu_group);
+	return group;
+
+out_remove_device:
+	iommu_group_remove_device(dev);
+out_put_group:
+	iommu_group_put(iommu_group);
+	return ERR_PTR(ret);
+}
+
+static bool vfio_group_has_device(struct vfio_group *group, struct device *dev)
+{
+	struct vfio_device *device;
+
+	mutex_lock(&group->device_lock);
+	list_for_each_entry(device, &group->device_list, group_next) {
+		if (device->dev == dev) {
+			mutex_unlock(&group->device_lock);
+			return true;
+		}
+	}
+	mutex_unlock(&group->device_lock);
+	return false;
+}
+
+static struct vfio_group *vfio_group_find_or_alloc(struct device *dev)
+{
+	struct iommu_group *iommu_group;
+	struct vfio_group *group;
+
+	iommu_group = iommu_group_get(dev);
+	if (!iommu_group && vfio_noiommu) {
+		/*
+		 * With noiommu enabled, create an IOMMU group for devices that
+		 * don't already have one, implying no IOMMU hardware/driver
+		 * exists.  Taint the kernel because we're about to give a DMA
+		 * capable device to a user without IOMMU protection.
+		 */
+		group = vfio_noiommu_group_alloc(dev, VFIO_NO_IOMMU);
+		if (!IS_ERR(group)) {
+			add_taint(TAINT_USER, LOCKDEP_STILL_OK);
+			dev_warn(dev, "Adding kernel taint for vfio-noiommu group on device\n");
+		}
+		return group;
+	}
+
+	if (!iommu_group)
+		return ERR_PTR(-EINVAL);
+
+	mutex_lock(&vfio.group_lock);
+	group = vfio_group_find_from_iommu(iommu_group);
+	if (group) {
+		if (WARN_ON(vfio_group_has_device(group, dev)))
+			group = ERR_PTR(-EINVAL);
+		else
+			refcount_inc(&group->drivers);
+	} else {
+		group = vfio_create_group(iommu_group, VFIO_IOMMU);
+	}
+	mutex_unlock(&vfio.group_lock);
+
+	/* The vfio_group holds a reference to the iommu_group */
+	iommu_group_put(iommu_group);
+	return group;
+}
+
+int vfio_device_set_group(struct vfio_device *device,
+			  enum vfio_group_type type)
+{
+	struct vfio_group *group;
+
+	if (type == VFIO_IOMMU)
+		group = vfio_group_find_or_alloc(device->dev);
+	else
+		group = vfio_noiommu_group_alloc(device->dev, type);
+
+	if (IS_ERR(group))
+		return PTR_ERR(group);
+
+	/* Our reference on group is moved to the device */
+	device->group = group;
+	return 0;
+}
+
+void vfio_device_remove_group(struct vfio_device *device)
+{
+	struct vfio_group *group = device->group;
+	struct iommu_group *iommu_group;
+
+	if (group->type == VFIO_NO_IOMMU || group->type == VFIO_EMULATED_IOMMU)
+		iommu_group_remove_device(device->dev);
+
+	/* Pairs with vfio_create_group() / vfio_group_get_from_iommu() */
+	if (!refcount_dec_and_mutex_lock(&group->drivers, &vfio.group_lock))
+		return;
+	list_del(&group->vfio_next);
+
+	/*
+	 * We could concurrently probe another driver in the group that might
+	 * race vfio_device_remove_group() with vfio_get_group(), so we have to
+	 * ensure that the sysfs is all cleaned up under lock otherwise the
+	 * cdev_device_add() will fail due to the name aready existing.
+	 */
+	cdev_device_del(&group->cdev, &group->dev);
+
+	mutex_lock(&group->group_lock);
+	/*
+	 * These data structures all have paired operations that can only be
+	 * undone when the caller holds a live reference on the device. Since
+	 * all pairs must be undone these WARN_ON's indicate some caller did not
+	 * properly hold the group reference.
+	 */
+	WARN_ON(!list_empty(&group->device_list));
+	WARN_ON(group->notifier.head);
+
+	/*
+	 * Revoke all users of group->iommu_group. At this point we know there
+	 * are no devices active because we are unplugging the last one. Setting
+	 * iommu_group to NULL blocks all new users.
+	 */
+	if (group->container)
+		vfio_group_detach_container(group);
+	iommu_group = group->iommu_group;
+	group->iommu_group = NULL;
+	mutex_unlock(&group->group_lock);
+	mutex_unlock(&vfio.group_lock);
+
+	iommu_group_put(iommu_group);
+	put_device(&group->dev);
+}
+
+void vfio_device_group_register(struct vfio_device *device)
+{
+	mutex_lock(&device->group->device_lock);
+	list_add(&device->group_next, &device->group->device_list);
+	mutex_unlock(&device->group->device_lock);
+}
+
+void vfio_device_group_unregister(struct vfio_device *device)
+{
+	mutex_lock(&device->group->device_lock);
+	list_del(&device->group_next);
+	mutex_unlock(&device->group->device_lock);
+}
+
+int vfio_device_group_use_iommu(struct vfio_device *device)
+{
+	struct vfio_group *group = device->group;
+	int ret = 0;
+
+	lockdep_assert_held(&group->group_lock);
+
+	if (WARN_ON(!group->container))
+		return -EINVAL;
+
+	ret = vfio_group_use_container(group);
+	if (ret)
+		return ret;
+	vfio_device_container_register(device);
+	return 0;
+}
+
+void vfio_device_group_unuse_iommu(struct vfio_device *device)
+{
+	struct vfio_group *group = device->group;
+
+	lockdep_assert_held(&group->group_lock);
+
+	if (WARN_ON(!group->container))
+		return;
+
+	vfio_device_container_unregister(device);
+	vfio_group_unuse_container(group);
+}
+
+bool vfio_device_has_container(struct vfio_device *device)
+{
+	return device->group->container;
+}
+
+struct vfio_group *vfio_group_from_file(struct file *file)
+{
+	struct vfio_group *group = file->private_data;
+
+	if (file->f_op != &vfio_group_fops)
+		return NULL;
+	return group;
+}
+
+/**
+ * vfio_file_iommu_group - Return the struct iommu_group for the vfio group file
+ * @file: VFIO group file
+ *
+ * The returned iommu_group is valid as long as a ref is held on the file. This
+ * returns a reference on the group. This function is deprecated, only the SPAPR
+ * path in kvm should call it.
+ */
+struct iommu_group *vfio_file_iommu_group(struct file *file)
+{
+	struct vfio_group *group = vfio_group_from_file(file);
+	struct iommu_group *iommu_group = NULL;
+
+	if (!IS_ENABLED(CONFIG_SPAPR_TCE_IOMMU))
+		return NULL;
+
+	if (!group)
+		return NULL;
+
+	mutex_lock(&group->group_lock);
+	if (group->iommu_group) {
+		iommu_group = group->iommu_group;
+		iommu_group_ref_get(iommu_group);
+	}
+	mutex_unlock(&group->group_lock);
+	return iommu_group;
+}
+EXPORT_SYMBOL_GPL(vfio_file_iommu_group);
+
+/**
+ * vfio_file_is_group - True if the file is a vfio group file
+ * @file: VFIO group file
+ */
+bool vfio_file_is_group(struct file *file)
+{
+	return vfio_group_from_file(file);
+}
+EXPORT_SYMBOL_GPL(vfio_file_is_group);
+
+bool vfio_group_enforced_coherent(struct vfio_group *group)
+{
+	struct vfio_device *device;
+	bool ret = true;
+
+	/*
+	 * If the device does not have IOMMU_CAP_ENFORCE_CACHE_COHERENCY then
+	 * any domain later attached to it will also not support it. If the cap
+	 * is set then the iommu_domain eventually attached to the device/group
+	 * must use a domain with enforce_cache_coherency().
+	 */
+	mutex_lock(&group->device_lock);
+	list_for_each_entry(device, &group->device_list, group_next) {
+		if (!device_iommu_capable(device->dev,
+					  IOMMU_CAP_ENFORCE_CACHE_COHERENCY)) {
+			ret = false;
+			break;
+		}
+	}
+	mutex_unlock(&group->device_lock);
+	return ret;
+}
+
+void vfio_group_set_kvm(struct vfio_group *group, struct kvm *kvm)
+{
+	spin_lock(&group->kvm_ref_lock);
+	group->kvm = kvm;
+	spin_unlock(&group->kvm_ref_lock);
+}
+
+/**
+ * vfio_file_has_dev - True if the VFIO file is a handle for device
+ * @file: VFIO file to check
+ * @device: Device that must be part of the file
+ *
+ * Returns true if given file has permission to manipulate the given device.
+ */
+bool vfio_file_has_dev(struct file *file, struct vfio_device *device)
+{
+	struct vfio_group *group = vfio_group_from_file(file);
+
+	if (!group)
+		return false;
+
+	return group == device->group;
+}
+EXPORT_SYMBOL_GPL(vfio_file_has_dev);
+
+static char *vfio_devnode(const struct device *dev, umode_t *mode)
+{
+	return kasprintf(GFP_KERNEL, "vfio/%s", dev_name(dev));
+}
+
+int __init vfio_group_init(void)
+{
+	int ret;
+
+	ida_init(&vfio.group_ida);
+	mutex_init(&vfio.group_lock);
+	INIT_LIST_HEAD(&vfio.group_list);
+
+	ret = vfio_container_init();
+	if (ret)
+		return ret;
+
+	/* /dev/vfio/$GROUP */
+	vfio.class = class_create("vfio");
+	if (IS_ERR(vfio.class)) {
+		ret = PTR_ERR(vfio.class);
+		goto err_group_class;
+	}
+
+	vfio.class->devnode = vfio_devnode;
+
+	ret = alloc_chrdev_region(&vfio.group_devt, 0, MINORMASK + 1, "vfio");
+	if (ret)
+		goto err_alloc_chrdev;
+	return 0;
+
+err_alloc_chrdev:
+	class_destroy(vfio.class);
+	vfio.class = NULL;
+err_group_class:
+	vfio_container_cleanup();
+	return ret;
+}
+
+void vfio_group_cleanup(void)
+{
+	WARN_ON(!list_empty(&vfio.group_list));
+	ida_destroy(&vfio.group_ida);
+	unregister_chrdev_region(vfio.group_devt, MINORMASK + 1);
+	class_destroy(vfio.class);
+	vfio.class = NULL;
+	vfio_container_cleanup();
+}