summaryrefslogtreecommitdiff
path: root/drivers/iommu/iommufd/main.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/iommu/iommufd/main.c')
-rw-r--r--drivers/iommu/iommufd/main.c808
1 files changed, 808 insertions, 0 deletions
diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c
new file mode 100644
index 000000000000..5cc4b08c25f5
--- /dev/null
+++ b/drivers/iommu/iommufd/main.c
@@ -0,0 +1,808 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (C) 2021 Intel Corporation
+ * Copyright (c) 2021-2022, NVIDIA CORPORATION & AFFILIATES
+ *
+ * iommufd provides control over the IOMMU HW objects created by IOMMU kernel
+ * drivers. IOMMU HW objects revolve around IO page tables that map incoming DMA
+ * addresses (IOVA) to CPU addresses.
+ */
+#define pr_fmt(fmt) "iommufd: " fmt
+
+#include <linux/bug.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/iommufd.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <uapi/linux/iommufd.h>
+
+#include "io_pagetable.h"
+#include "iommufd_private.h"
+#include "iommufd_test.h"
+
+struct iommufd_object_ops {
+ size_t file_offset;
+ void (*pre_destroy)(struct iommufd_object *obj);
+ void (*destroy)(struct iommufd_object *obj);
+ void (*abort)(struct iommufd_object *obj);
+};
+static const struct iommufd_object_ops iommufd_object_ops[];
+static struct miscdevice vfio_misc_dev;
+
+struct iommufd_object *_iommufd_object_alloc(struct iommufd_ctx *ictx,
+ size_t size,
+ enum iommufd_object_type type)
+{
+ struct iommufd_object *obj;
+ int rc;
+
+ obj = kzalloc(size, GFP_KERNEL_ACCOUNT);
+ if (!obj)
+ return ERR_PTR(-ENOMEM);
+ obj->type = type;
+ /* Starts out bias'd by 1 until it is removed from the xarray */
+ refcount_set(&obj->wait_cnt, 1);
+ refcount_set(&obj->users, 1);
+
+ /*
+ * Reserve an ID in the xarray but do not publish the pointer yet since
+ * the caller hasn't initialized it yet. Once the pointer is published
+ * in the xarray and visible to other threads we can't reliably destroy
+ * it anymore, so the caller must complete all errorable operations
+ * before calling iommufd_object_finalize().
+ */
+ rc = xa_alloc(&ictx->objects, &obj->id, XA_ZERO_ENTRY, xa_limit_31b,
+ GFP_KERNEL_ACCOUNT);
+ if (rc)
+ goto out_free;
+ return obj;
+out_free:
+ kfree(obj);
+ return ERR_PTR(rc);
+}
+
+struct iommufd_object *_iommufd_object_alloc_ucmd(struct iommufd_ucmd *ucmd,
+ size_t size,
+ enum iommufd_object_type type)
+{
+ struct iommufd_object *new_obj;
+
+ /* Something is coded wrong if this is hit */
+ if (WARN_ON(ucmd->new_obj))
+ return ERR_PTR(-EBUSY);
+
+ /*
+ * An abort op means that its caller needs to invoke it within a lock in
+ * the caller. So it doesn't work with _iommufd_object_alloc_ucmd() that
+ * will invoke the abort op in iommufd_object_abort_and_destroy(), which
+ * must be outside the caller's lock.
+ */
+ if (WARN_ON(iommufd_object_ops[type].abort))
+ return ERR_PTR(-EOPNOTSUPP);
+
+ new_obj = _iommufd_object_alloc(ucmd->ictx, size, type);
+ if (IS_ERR(new_obj))
+ return new_obj;
+
+ ucmd->new_obj = new_obj;
+ return new_obj;
+}
+
+/*
+ * Allow concurrent access to the object.
+ *
+ * Once another thread can see the object pointer it can prevent object
+ * destruction. Expect for special kernel-only objects there is no in-kernel way
+ * to reliably destroy a single object. Thus all APIs that are creating objects
+ * must use iommufd_object_abort() to handle their errors and only call
+ * iommufd_object_finalize() once object creation cannot fail.
+ */
+void iommufd_object_finalize(struct iommufd_ctx *ictx,
+ struct iommufd_object *obj)
+{
+ XA_STATE(xas, &ictx->objects, obj->id);
+ void *old;
+
+ xa_lock(&ictx->objects);
+ old = xas_store(&xas, obj);
+ xa_unlock(&ictx->objects);
+ /* obj->id was returned from xa_alloc() so the xas_store() cannot fail */
+ WARN_ON(old != XA_ZERO_ENTRY);
+}
+
+/* Undo _iommufd_object_alloc() if iommufd_object_finalize() was not called */
+void iommufd_object_abort(struct iommufd_ctx *ictx, struct iommufd_object *obj)
+{
+ XA_STATE(xas, &ictx->objects, obj->id);
+ void *old;
+
+ xa_lock(&ictx->objects);
+ old = xas_store(&xas, NULL);
+ xa_unlock(&ictx->objects);
+ WARN_ON(old != XA_ZERO_ENTRY);
+
+ if (WARN_ON(!refcount_dec_and_test(&obj->users)))
+ return;
+
+ kfree(obj);
+}
+
+/*
+ * Abort an object that has been fully initialized and needs destroy, but has
+ * not been finalized.
+ */
+void iommufd_object_abort_and_destroy(struct iommufd_ctx *ictx,
+ struct iommufd_object *obj)
+{
+ const struct iommufd_object_ops *ops = &iommufd_object_ops[obj->type];
+
+ if (ops->file_offset) {
+ struct file **filep = ((void *)obj) + ops->file_offset;
+
+ /*
+ * A file should hold a users refcount while the file is open
+ * and put it back in its release. The file should hold a
+ * pointer to obj in their private data. Normal fput() is
+ * deferred to a workqueue and can get out of order with the
+ * following kfree(obj). Using the sync version ensures the
+ * release happens immediately. During abort we require the file
+ * refcount is one at this point - meaning the object alloc
+ * function cannot do anything to allow another thread to take a
+ * refcount prior to a guaranteed success.
+ */
+ if (*filep)
+ __fput_sync(*filep);
+ }
+
+ if (ops->abort)
+ ops->abort(obj);
+ else
+ ops->destroy(obj);
+ iommufd_object_abort(ictx, obj);
+}
+
+struct iommufd_object *iommufd_get_object(struct iommufd_ctx *ictx, u32 id,
+ enum iommufd_object_type type)
+{
+ struct iommufd_object *obj;
+
+ if (iommufd_should_fail())
+ return ERR_PTR(-ENOENT);
+
+ xa_lock(&ictx->objects);
+ obj = xa_load(&ictx->objects, id);
+ if (!obj || (type != IOMMUFD_OBJ_ANY && obj->type != type) ||
+ !iommufd_lock_obj(obj))
+ obj = ERR_PTR(-ENOENT);
+ xa_unlock(&ictx->objects);
+ return obj;
+}
+
+static int iommufd_object_dec_wait(struct iommufd_ctx *ictx,
+ struct iommufd_object *to_destroy)
+{
+ if (refcount_dec_and_test(&to_destroy->wait_cnt))
+ return 0;
+
+ if (iommufd_object_ops[to_destroy->type].pre_destroy)
+ iommufd_object_ops[to_destroy->type].pre_destroy(to_destroy);
+
+ if (wait_event_timeout(ictx->destroy_wait,
+ refcount_read(&to_destroy->wait_cnt) == 0,
+ msecs_to_jiffies(60000)))
+ return 0;
+
+ pr_crit("Time out waiting for iommufd object to become free\n");
+ refcount_inc(&to_destroy->wait_cnt);
+ return -EBUSY;
+}
+
+/*
+ * Remove the given object id from the xarray if the only reference to the
+ * object is held by the xarray.
+ */
+int iommufd_object_remove(struct iommufd_ctx *ictx,
+ struct iommufd_object *to_destroy, u32 id,
+ unsigned int flags)
+{
+ struct iommufd_object *obj;
+ XA_STATE(xas, &ictx->objects, id);
+ bool zerod_wait_cnt = false;
+ int ret;
+
+ /*
+ * The purpose of the wait_cnt is to ensure deterministic destruction
+ * of objects used by external drivers and destroyed by this function.
+ * Incrementing this wait_cnt should either be short lived, such as
+ * during ioctl execution, or be revoked and blocked during
+ * pre_destroy(), such as vdev holding the idev's refcount.
+ */
+ if (flags & REMOVE_WAIT) {
+ ret = iommufd_object_dec_wait(ictx, to_destroy);
+ if (ret) {
+ /*
+ * We have a bug. Put back the callers reference and
+ * defer cleaning this object until close.
+ */
+ refcount_dec(&to_destroy->users);
+ return ret;
+ }
+ zerod_wait_cnt = true;
+ }
+
+ xa_lock(&ictx->objects);
+ obj = xas_load(&xas);
+ if (to_destroy) {
+ /*
+ * If the caller is holding a ref on obj we put it here under
+ * the spinlock.
+ */
+ refcount_dec(&obj->users);
+
+ if (WARN_ON(obj != to_destroy)) {
+ ret = -ENOENT;
+ goto err_xa;
+ }
+ } else if (xa_is_zero(obj) || !obj) {
+ ret = -ENOENT;
+ goto err_xa;
+ }
+
+ if (!refcount_dec_if_one(&obj->users)) {
+ ret = -EBUSY;
+ goto err_xa;
+ }
+
+ xas_store(&xas, (flags & REMOVE_OBJ_TOMBSTONE) ? XA_ZERO_ENTRY : NULL);
+ if (ictx->vfio_ioas == container_of(obj, struct iommufd_ioas, obj))
+ ictx->vfio_ioas = NULL;
+ xa_unlock(&ictx->objects);
+
+ /*
+ * Since users is zero any positive wait_cnt must be racing
+ * iommufd_put_object(), or we have a bug.
+ */
+ if (!zerod_wait_cnt) {
+ ret = iommufd_object_dec_wait(ictx, obj);
+ if (WARN_ON(ret))
+ return ret;
+ }
+
+ iommufd_object_ops[obj->type].destroy(obj);
+ kfree(obj);
+ return 0;
+
+err_xa:
+ if (zerod_wait_cnt) {
+ /* Restore the xarray owned reference */
+ refcount_set(&obj->wait_cnt, 1);
+ }
+ xa_unlock(&ictx->objects);
+
+ /* The returned object reference count is zero */
+ return ret;
+}
+
+static int iommufd_destroy(struct iommufd_ucmd *ucmd)
+{
+ struct iommu_destroy *cmd = ucmd->cmd;
+
+ return iommufd_object_remove(ucmd->ictx, NULL, cmd->id, 0);
+}
+
+static int iommufd_fops_open(struct inode *inode, struct file *filp)
+{
+ struct iommufd_ctx *ictx;
+
+ ictx = kzalloc(sizeof(*ictx), GFP_KERNEL_ACCOUNT);
+ if (!ictx)
+ return -ENOMEM;
+
+ /*
+ * For compatibility with VFIO when /dev/vfio/vfio is opened we default
+ * to the same rlimit accounting as vfio uses.
+ */
+ if (IS_ENABLED(CONFIG_IOMMUFD_VFIO_CONTAINER) &&
+ filp->private_data == &vfio_misc_dev) {
+ ictx->account_mode = IOPT_PAGES_ACCOUNT_MM;
+ pr_info_once("IOMMUFD is providing /dev/vfio/vfio, not VFIO.\n");
+ }
+
+ init_rwsem(&ictx->ioas_creation_lock);
+ xa_init_flags(&ictx->objects, XA_FLAGS_ALLOC1 | XA_FLAGS_ACCOUNT);
+ xa_init(&ictx->groups);
+ ictx->file = filp;
+ mt_init_flags(&ictx->mt_mmap, MT_FLAGS_ALLOC_RANGE);
+ init_waitqueue_head(&ictx->destroy_wait);
+ mutex_init(&ictx->sw_msi_lock);
+ INIT_LIST_HEAD(&ictx->sw_msi_list);
+ filp->private_data = ictx;
+ return 0;
+}
+
+static int iommufd_fops_release(struct inode *inode, struct file *filp)
+{
+ struct iommufd_ctx *ictx = filp->private_data;
+ struct iommufd_sw_msi_map *next;
+ struct iommufd_sw_msi_map *cur;
+ struct iommufd_object *obj;
+
+ /*
+ * The objects in the xarray form a graph of "users" counts, and we have
+ * to destroy them in a depth first manner. Leaf objects will reduce the
+ * users count of interior objects when they are destroyed.
+ *
+ * Repeatedly destroying all the "1 users" leaf objects will progress
+ * until the entire list is destroyed. If this can't progress then there
+ * is some bug related to object refcounting.
+ */
+ while (!xa_empty(&ictx->objects)) {
+ unsigned int destroyed = 0;
+ unsigned long index;
+ bool empty = true;
+
+ /*
+ * We can't use xa_empty() to end the loop as the tombstones
+ * are stored as XA_ZERO_ENTRY in the xarray. However
+ * xa_for_each() automatically converts them to NULL and skips
+ * them causing xa_empty() to be kept false. Thus once
+ * xa_for_each() finds no further !NULL entries the loop is
+ * done.
+ */
+ xa_for_each(&ictx->objects, index, obj) {
+ empty = false;
+ if (!refcount_dec_if_one(&obj->users))
+ continue;
+
+ destroyed++;
+ xa_erase(&ictx->objects, index);
+ iommufd_object_ops[obj->type].destroy(obj);
+ kfree(obj);
+ }
+
+ if (empty)
+ break;
+
+ /* Bug related to users refcount */
+ if (WARN_ON(!destroyed))
+ break;
+ }
+
+ /*
+ * There may be some tombstones left over from
+ * iommufd_object_tombstone_user()
+ */
+ xa_destroy(&ictx->objects);
+
+ WARN_ON(!xa_empty(&ictx->groups));
+
+ mutex_destroy(&ictx->sw_msi_lock);
+ list_for_each_entry_safe(cur, next, &ictx->sw_msi_list, sw_msi_item)
+ kfree(cur);
+
+ kfree(ictx);
+ return 0;
+}
+
+static int iommufd_option(struct iommufd_ucmd *ucmd)
+{
+ struct iommu_option *cmd = ucmd->cmd;
+ int rc;
+
+ if (cmd->__reserved)
+ return -EOPNOTSUPP;
+
+ switch (cmd->option_id) {
+ case IOMMU_OPTION_RLIMIT_MODE:
+ rc = iommufd_option_rlimit_mode(cmd, ucmd->ictx);
+ break;
+ case IOMMU_OPTION_HUGE_PAGES:
+ rc = iommufd_ioas_option(ucmd);
+ break;
+ default:
+ return -EOPNOTSUPP;
+ }
+ if (rc)
+ return rc;
+ if (copy_to_user(&((struct iommu_option __user *)ucmd->ubuffer)->val64,
+ &cmd->val64, sizeof(cmd->val64)))
+ return -EFAULT;
+ return 0;
+}
+
+union ucmd_buffer {
+ struct iommu_destroy destroy;
+ struct iommu_fault_alloc fault;
+ struct iommu_hw_info info;
+ struct iommu_hw_queue_alloc hw_queue;
+ struct iommu_hwpt_alloc hwpt;
+ struct iommu_hwpt_get_dirty_bitmap get_dirty_bitmap;
+ struct iommu_hwpt_invalidate cache;
+ struct iommu_hwpt_set_dirty_tracking set_dirty_tracking;
+ struct iommu_ioas_alloc alloc;
+ struct iommu_ioas_allow_iovas allow_iovas;
+ struct iommu_ioas_copy ioas_copy;
+ struct iommu_ioas_iova_ranges iova_ranges;
+ struct iommu_ioas_map map;
+ struct iommu_ioas_unmap unmap;
+ struct iommu_option option;
+ struct iommu_vdevice_alloc vdev;
+ struct iommu_veventq_alloc veventq;
+ struct iommu_vfio_ioas vfio_ioas;
+ struct iommu_viommu_alloc viommu;
+#ifdef CONFIG_IOMMUFD_TEST
+ struct iommu_test_cmd test;
+#endif
+};
+
+struct iommufd_ioctl_op {
+ unsigned int size;
+ unsigned int min_size;
+ unsigned int ioctl_num;
+ int (*execute)(struct iommufd_ucmd *ucmd);
+};
+
+#define IOCTL_OP(_ioctl, _fn, _struct, _last) \
+ [_IOC_NR(_ioctl) - IOMMUFD_CMD_BASE] = { \
+ .size = sizeof(_struct) + \
+ BUILD_BUG_ON_ZERO(sizeof(union ucmd_buffer) < \
+ sizeof(_struct)), \
+ .min_size = offsetofend(_struct, _last), \
+ .ioctl_num = _ioctl, \
+ .execute = _fn, \
+ }
+static const struct iommufd_ioctl_op iommufd_ioctl_ops[] = {
+ IOCTL_OP(IOMMU_DESTROY, iommufd_destroy, struct iommu_destroy, id),
+ IOCTL_OP(IOMMU_FAULT_QUEUE_ALLOC, iommufd_fault_alloc,
+ struct iommu_fault_alloc, out_fault_fd),
+ IOCTL_OP(IOMMU_GET_HW_INFO, iommufd_get_hw_info, struct iommu_hw_info,
+ __reserved),
+ IOCTL_OP(IOMMU_HW_QUEUE_ALLOC, iommufd_hw_queue_alloc_ioctl,
+ struct iommu_hw_queue_alloc, length),
+ IOCTL_OP(IOMMU_HWPT_ALLOC, iommufd_hwpt_alloc, struct iommu_hwpt_alloc,
+ __reserved),
+ IOCTL_OP(IOMMU_HWPT_GET_DIRTY_BITMAP, iommufd_hwpt_get_dirty_bitmap,
+ struct iommu_hwpt_get_dirty_bitmap, data),
+ IOCTL_OP(IOMMU_HWPT_INVALIDATE, iommufd_hwpt_invalidate,
+ struct iommu_hwpt_invalidate, __reserved),
+ IOCTL_OP(IOMMU_HWPT_SET_DIRTY_TRACKING, iommufd_hwpt_set_dirty_tracking,
+ struct iommu_hwpt_set_dirty_tracking, __reserved),
+ IOCTL_OP(IOMMU_IOAS_ALLOC, iommufd_ioas_alloc_ioctl,
+ struct iommu_ioas_alloc, out_ioas_id),
+ IOCTL_OP(IOMMU_IOAS_ALLOW_IOVAS, iommufd_ioas_allow_iovas,
+ struct iommu_ioas_allow_iovas, allowed_iovas),
+ IOCTL_OP(IOMMU_IOAS_CHANGE_PROCESS, iommufd_ioas_change_process,
+ struct iommu_ioas_change_process, __reserved),
+ IOCTL_OP(IOMMU_IOAS_COPY, iommufd_ioas_copy, struct iommu_ioas_copy,
+ src_iova),
+ IOCTL_OP(IOMMU_IOAS_IOVA_RANGES, iommufd_ioas_iova_ranges,
+ struct iommu_ioas_iova_ranges, out_iova_alignment),
+ IOCTL_OP(IOMMU_IOAS_MAP, iommufd_ioas_map, struct iommu_ioas_map, iova),
+ IOCTL_OP(IOMMU_IOAS_MAP_FILE, iommufd_ioas_map_file,
+ struct iommu_ioas_map_file, iova),
+ IOCTL_OP(IOMMU_IOAS_UNMAP, iommufd_ioas_unmap, struct iommu_ioas_unmap,
+ length),
+ IOCTL_OP(IOMMU_OPTION, iommufd_option, struct iommu_option, val64),
+ IOCTL_OP(IOMMU_VDEVICE_ALLOC, iommufd_vdevice_alloc_ioctl,
+ struct iommu_vdevice_alloc, virt_id),
+ IOCTL_OP(IOMMU_VEVENTQ_ALLOC, iommufd_veventq_alloc,
+ struct iommu_veventq_alloc, out_veventq_fd),
+ IOCTL_OP(IOMMU_VFIO_IOAS, iommufd_vfio_ioas, struct iommu_vfio_ioas,
+ __reserved),
+ IOCTL_OP(IOMMU_VIOMMU_ALLOC, iommufd_viommu_alloc_ioctl,
+ struct iommu_viommu_alloc, out_viommu_id),
+#ifdef CONFIG_IOMMUFD_TEST
+ IOCTL_OP(IOMMU_TEST_CMD, iommufd_test, struct iommu_test_cmd, last),
+#endif
+};
+
+static long iommufd_fops_ioctl(struct file *filp, unsigned int cmd,
+ unsigned long arg)
+{
+ struct iommufd_ctx *ictx = filp->private_data;
+ const struct iommufd_ioctl_op *op;
+ struct iommufd_ucmd ucmd = {};
+ union ucmd_buffer buf;
+ unsigned int nr;
+ int ret;
+
+ nr = _IOC_NR(cmd);
+ if (nr < IOMMUFD_CMD_BASE ||
+ (nr - IOMMUFD_CMD_BASE) >= ARRAY_SIZE(iommufd_ioctl_ops))
+ return iommufd_vfio_ioctl(ictx, cmd, arg);
+
+ ucmd.ictx = ictx;
+ ucmd.ubuffer = (void __user *)arg;
+ ret = get_user(ucmd.user_size, (u32 __user *)ucmd.ubuffer);
+ if (ret)
+ return ret;
+
+ op = &iommufd_ioctl_ops[nr - IOMMUFD_CMD_BASE];
+ if (op->ioctl_num != cmd)
+ return -ENOIOCTLCMD;
+ if (ucmd.user_size < op->min_size)
+ return -EINVAL;
+
+ ucmd.cmd = &buf;
+ ret = copy_struct_from_user(ucmd.cmd, op->size, ucmd.ubuffer,
+ ucmd.user_size);
+ if (ret)
+ return ret;
+ ret = op->execute(&ucmd);
+
+ if (ucmd.new_obj) {
+ if (ret)
+ iommufd_object_abort_and_destroy(ictx, ucmd.new_obj);
+ else
+ iommufd_object_finalize(ictx, ucmd.new_obj);
+ }
+ return ret;
+}
+
+static void iommufd_fops_vma_open(struct vm_area_struct *vma)
+{
+ struct iommufd_mmap *immap = vma->vm_private_data;
+
+ refcount_inc(&immap->owner->users);
+}
+
+static void iommufd_fops_vma_close(struct vm_area_struct *vma)
+{
+ struct iommufd_mmap *immap = vma->vm_private_data;
+
+ refcount_dec(&immap->owner->users);
+}
+
+static const struct vm_operations_struct iommufd_vma_ops = {
+ .open = iommufd_fops_vma_open,
+ .close = iommufd_fops_vma_close,
+};
+
+/* The vm_pgoff must be pre-allocated from mt_mmap, and given to user space */
+static int iommufd_fops_mmap(struct file *filp, struct vm_area_struct *vma)
+{
+ struct iommufd_ctx *ictx = filp->private_data;
+ size_t length = vma->vm_end - vma->vm_start;
+ struct iommufd_mmap *immap;
+ int rc;
+
+ if (!PAGE_ALIGNED(length))
+ return -EINVAL;
+ if (!(vma->vm_flags & VM_SHARED))
+ return -EINVAL;
+ if (vma->vm_flags & VM_EXEC)
+ return -EPERM;
+
+ mtree_lock(&ictx->mt_mmap);
+ /* vma->vm_pgoff carries a page-shifted start position to an immap */
+ immap = mtree_load(&ictx->mt_mmap, vma->vm_pgoff << PAGE_SHIFT);
+ if (!immap || !refcount_inc_not_zero(&immap->owner->users)) {
+ mtree_unlock(&ictx->mt_mmap);
+ return -ENXIO;
+ }
+ mtree_unlock(&ictx->mt_mmap);
+
+ /*
+ * mtree_load() returns the immap for any contained mmio_addr, so only
+ * allow the exact immap thing to be mapped
+ */
+ if (vma->vm_pgoff != immap->vm_pgoff || length != immap->length) {
+ rc = -ENXIO;
+ goto err_refcount;
+ }
+
+ vma->vm_pgoff = 0;
+ vma->vm_private_data = immap;
+ vma->vm_ops = &iommufd_vma_ops;
+ vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+
+ rc = io_remap_pfn_range(vma, vma->vm_start,
+ immap->mmio_addr >> PAGE_SHIFT, length,
+ vma->vm_page_prot);
+ if (rc)
+ goto err_refcount;
+ return 0;
+
+err_refcount:
+ refcount_dec(&immap->owner->users);
+ return rc;
+}
+
+static const struct file_operations iommufd_fops = {
+ .owner = THIS_MODULE,
+ .open = iommufd_fops_open,
+ .release = iommufd_fops_release,
+ .unlocked_ioctl = iommufd_fops_ioctl,
+ .mmap = iommufd_fops_mmap,
+};
+
+/**
+ * iommufd_ctx_get - Get a context reference
+ * @ictx: Context to get
+ *
+ * The caller must already hold a valid reference to ictx.
+ */
+void iommufd_ctx_get(struct iommufd_ctx *ictx)
+{
+ get_file(ictx->file);
+}
+EXPORT_SYMBOL_NS_GPL(iommufd_ctx_get, "IOMMUFD");
+
+/**
+ * iommufd_ctx_from_file - Acquires a reference to the iommufd context
+ * @file: File to obtain the reference from
+ *
+ * Returns a pointer to the iommufd_ctx, otherwise ERR_PTR. The struct file
+ * remains owned by the caller and the caller must still do fput. On success
+ * the caller is responsible to call iommufd_ctx_put().
+ */
+struct iommufd_ctx *iommufd_ctx_from_file(struct file *file)
+{
+ struct iommufd_ctx *ictx;
+
+ if (file->f_op != &iommufd_fops)
+ return ERR_PTR(-EBADFD);
+ ictx = file->private_data;
+ iommufd_ctx_get(ictx);
+ return ictx;
+}
+EXPORT_SYMBOL_NS_GPL(iommufd_ctx_from_file, "IOMMUFD");
+
+/**
+ * iommufd_ctx_from_fd - Acquires a reference to the iommufd context
+ * @fd: File descriptor to obtain the reference from
+ *
+ * Returns a pointer to the iommufd_ctx, otherwise ERR_PTR. On success
+ * the caller is responsible to call iommufd_ctx_put().
+ */
+struct iommufd_ctx *iommufd_ctx_from_fd(int fd)
+{
+ struct file *file;
+
+ file = fget(fd);
+ if (!file)
+ return ERR_PTR(-EBADF);
+
+ if (file->f_op != &iommufd_fops) {
+ fput(file);
+ return ERR_PTR(-EBADFD);
+ }
+ /* fget is the same as iommufd_ctx_get() */
+ return file->private_data;
+}
+EXPORT_SYMBOL_NS_GPL(iommufd_ctx_from_fd, "IOMMUFD");
+
+/**
+ * iommufd_ctx_put - Put back a reference
+ * @ictx: Context to put back
+ */
+void iommufd_ctx_put(struct iommufd_ctx *ictx)
+{
+ fput(ictx->file);
+}
+EXPORT_SYMBOL_NS_GPL(iommufd_ctx_put, "IOMMUFD");
+
+#define IOMMUFD_FILE_OFFSET(_struct, _filep, _obj) \
+ .file_offset = (offsetof(_struct, _filep) + \
+ BUILD_BUG_ON_ZERO(!__same_type( \
+ struct file *, ((_struct *)NULL)->_filep)) + \
+ BUILD_BUG_ON_ZERO(offsetof(_struct, _obj)))
+
+static const struct iommufd_object_ops iommufd_object_ops[] = {
+ [IOMMUFD_OBJ_ACCESS] = {
+ .destroy = iommufd_access_destroy_object,
+ },
+ [IOMMUFD_OBJ_DEVICE] = {
+ .pre_destroy = iommufd_device_pre_destroy,
+ .destroy = iommufd_device_destroy,
+ },
+ [IOMMUFD_OBJ_FAULT] = {
+ .destroy = iommufd_fault_destroy,
+ IOMMUFD_FILE_OFFSET(struct iommufd_fault, common.filep, common.obj),
+ },
+ [IOMMUFD_OBJ_HW_QUEUE] = {
+ .destroy = iommufd_hw_queue_destroy,
+ },
+ [IOMMUFD_OBJ_HWPT_PAGING] = {
+ .destroy = iommufd_hwpt_paging_destroy,
+ .abort = iommufd_hwpt_paging_abort,
+ },
+ [IOMMUFD_OBJ_HWPT_NESTED] = {
+ .destroy = iommufd_hwpt_nested_destroy,
+ .abort = iommufd_hwpt_nested_abort,
+ },
+ [IOMMUFD_OBJ_IOAS] = {
+ .destroy = iommufd_ioas_destroy,
+ },
+ [IOMMUFD_OBJ_VDEVICE] = {
+ .destroy = iommufd_vdevice_destroy,
+ .abort = iommufd_vdevice_abort,
+ },
+ [IOMMUFD_OBJ_VEVENTQ] = {
+ .destroy = iommufd_veventq_destroy,
+ .abort = iommufd_veventq_abort,
+ IOMMUFD_FILE_OFFSET(struct iommufd_veventq, common.filep, common.obj),
+ },
+ [IOMMUFD_OBJ_VIOMMU] = {
+ .destroy = iommufd_viommu_destroy,
+ },
+#ifdef CONFIG_IOMMUFD_TEST
+ [IOMMUFD_OBJ_SELFTEST] = {
+ .destroy = iommufd_selftest_destroy,
+ },
+#endif
+};
+
+static struct miscdevice iommu_misc_dev = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = "iommu",
+ .fops = &iommufd_fops,
+ .nodename = "iommu",
+ .mode = 0660,
+};
+
+static struct miscdevice vfio_misc_dev = {
+ .minor = VFIO_MINOR,
+ .name = "vfio",
+ .fops = &iommufd_fops,
+ .nodename = "vfio/vfio",
+ .mode = 0666,
+};
+
+/*
+ * Used only by DMABUF, returns a valid struct device to use as a dummy struct
+ * device for attachment.
+ */
+struct device *iommufd_global_device(void)
+{
+ return iommu_misc_dev.this_device;
+}
+
+static int __init iommufd_init(void)
+{
+ int ret;
+
+ ret = misc_register(&iommu_misc_dev);
+ if (ret)
+ return ret;
+
+ if (IS_ENABLED(CONFIG_IOMMUFD_VFIO_CONTAINER)) {
+ ret = misc_register(&vfio_misc_dev);
+ if (ret)
+ goto err_misc;
+ }
+ ret = iommufd_test_init();
+ if (ret)
+ goto err_vfio_misc;
+ return 0;
+
+err_vfio_misc:
+ if (IS_ENABLED(CONFIG_IOMMUFD_VFIO_CONTAINER))
+ misc_deregister(&vfio_misc_dev);
+err_misc:
+ misc_deregister(&iommu_misc_dev);
+ return ret;
+}
+
+static void __exit iommufd_exit(void)
+{
+ iommufd_test_exit();
+ if (IS_ENABLED(CONFIG_IOMMUFD_VFIO_CONTAINER))
+ misc_deregister(&vfio_misc_dev);
+ misc_deregister(&iommu_misc_dev);
+}
+
+module_init(iommufd_init);
+module_exit(iommufd_exit);
+
+#if IS_ENABLED(CONFIG_IOMMUFD_VFIO_CONTAINER)
+MODULE_ALIAS_MISCDEV(VFIO_MINOR);
+MODULE_ALIAS("devname:vfio/vfio");
+#endif
+MODULE_IMPORT_NS("IOMMUFD_INTERNAL");
+MODULE_IMPORT_NS("IOMMUFD");
+MODULE_IMPORT_NS("DMA_BUF");
+MODULE_DESCRIPTION("I/O Address Space Management for passthrough devices");
+MODULE_LICENSE("GPL");