1 // SPDX-License-Identifier: GPL-2.0-only
3 * Mediated device Core Driver
5 * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
6 * Author: Neo Jia <cjia@nvidia.com>
7 * Kirti Wankhede <kwankhede@nvidia.com>
10 #include <linux/module.h>
11 #include <linux/device.h>
12 #include <linux/slab.h>
13 #include <linux/uuid.h>
14 #include <linux/sysfs.h>
15 #include <linux/mdev.h>
17 #include "mdev_private.h"
19 #define DRIVER_VERSION "0.1"
20 #define DRIVER_AUTHOR "NVIDIA Corporation"
21 #define DRIVER_DESC "Mediated device Core Driver"
23 static LIST_HEAD(parent_list);
24 static DEFINE_MUTEX(parent_list_lock);
25 static struct class_compat *mdev_bus_compat_class;
27 static LIST_HEAD(mdev_list);
28 static DEFINE_MUTEX(mdev_list_lock);
30 struct device *mdev_parent_dev(struct mdev_device *mdev)
32 return mdev->type->parent->dev;
34 EXPORT_SYMBOL(mdev_parent_dev);
37 * Return the index in supported_type_groups that this mdev_device was created
40 unsigned int mdev_get_type_group_id(struct mdev_device *mdev)
42 return mdev->type->type_group_id;
44 EXPORT_SYMBOL(mdev_get_type_group_id);
47 * Used in mdev_type_attribute sysfs functions to return the index in the
48 * supported_type_groups that the sysfs is called from.
50 unsigned int mtype_get_type_group_id(struct mdev_type *mtype)
52 return mtype->type_group_id;
54 EXPORT_SYMBOL(mtype_get_type_group_id);
57 * Used in mdev_type_attribute sysfs functions to return the parent struct
60 struct device *mtype_get_parent_dev(struct mdev_type *mtype)
62 return mtype->parent->dev;
64 EXPORT_SYMBOL(mtype_get_parent_dev);
66 /* Should be called holding parent_list_lock */
67 static struct mdev_parent *__find_parent_device(struct device *dev)
69 struct mdev_parent *parent;
71 list_for_each_entry(parent, &parent_list, next) {
72 if (parent->dev == dev)
78 void mdev_release_parent(struct kref *kref)
80 struct mdev_parent *parent = container_of(kref, struct mdev_parent,
82 struct device *dev = parent->dev;
88 /* Caller must hold parent unreg_sem read or write lock */
89 static void mdev_device_remove_common(struct mdev_device *mdev)
91 struct mdev_parent *parent = mdev->type->parent;
94 mdev_remove_sysfs_files(mdev);
95 device_del(&mdev->dev);
96 lockdep_assert_held(&parent->unreg_sem);
97 if (parent->ops->remove) {
98 ret = parent->ops->remove(mdev);
100 dev_err(&mdev->dev, "Remove failed: err=%d\n", ret);
103 /* Balances with device_initialize() */
104 put_device(&mdev->dev);
107 static int mdev_device_remove_cb(struct device *dev, void *data)
109 struct mdev_device *mdev = mdev_from_dev(dev);
112 mdev_device_remove_common(mdev);
117 * mdev_register_device : Register a device
118 * @dev: device structure representing parent device.
119 * @ops: Parent device operation structure to be registered.
121 * Add device to list of registered parent devices.
122 * Returns a negative value on error, otherwise 0.
124 int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops)
127 struct mdev_parent *parent;
128 char *env_string = "MDEV_STATE=registered";
129 char *envp[] = { env_string, NULL };
131 /* check for mandatory ops */
132 if (!ops || !ops->supported_type_groups)
134 if (!ops->device_driver && (!ops->create || !ops->remove))
137 dev = get_device(dev);
141 /* Not mandatory, but its absence could be a problem */
143 dev_info(dev, "Driver cannot be asked to release device\n");
145 mutex_lock(&parent_list_lock);
147 /* Check for duplicate */
148 parent = __find_parent_device(dev);
155 parent = kzalloc(sizeof(*parent), GFP_KERNEL);
161 kref_init(&parent->ref);
162 init_rwsem(&parent->unreg_sem);
167 if (!mdev_bus_compat_class) {
168 mdev_bus_compat_class = class_compat_register("mdev_bus");
169 if (!mdev_bus_compat_class) {
175 ret = parent_create_sysfs_files(parent);
179 ret = class_compat_create_link(mdev_bus_compat_class, dev, NULL);
181 dev_warn(dev, "Failed to create compatibility class link\n");
183 list_add(&parent->next, &parent_list);
184 mutex_unlock(&parent_list_lock);
186 dev_info(dev, "MDEV: Registered\n");
187 kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp);
192 mutex_unlock(&parent_list_lock);
194 mdev_put_parent(parent);
199 EXPORT_SYMBOL(mdev_register_device);
202 * mdev_unregister_device : Unregister a parent device
203 * @dev: device structure representing parent device.
205 * Remove device from list of registered parent devices. Give a chance to free
206 * existing mediated devices for given device.
209 void mdev_unregister_device(struct device *dev)
211 struct mdev_parent *parent;
212 char *env_string = "MDEV_STATE=unregistered";
213 char *envp[] = { env_string, NULL };
215 mutex_lock(&parent_list_lock);
216 parent = __find_parent_device(dev);
219 mutex_unlock(&parent_list_lock);
222 dev_info(dev, "MDEV: Unregistering\n");
224 list_del(&parent->next);
225 mutex_unlock(&parent_list_lock);
227 down_write(&parent->unreg_sem);
229 class_compat_remove_link(mdev_bus_compat_class, dev, NULL);
231 device_for_each_child(dev, NULL, mdev_device_remove_cb);
233 parent_remove_sysfs_files(parent);
234 up_write(&parent->unreg_sem);
236 mdev_put_parent(parent);
238 /* We still have the caller's reference to use for the uevent */
239 kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp);
241 EXPORT_SYMBOL(mdev_unregister_device);
243 static void mdev_device_release(struct device *dev)
245 struct mdev_device *mdev = to_mdev_device(dev);
247 /* Pairs with the get in mdev_device_create() */
248 kobject_put(&mdev->type->kobj);
250 mutex_lock(&mdev_list_lock);
251 list_del(&mdev->next);
252 mutex_unlock(&mdev_list_lock);
254 dev_dbg(&mdev->dev, "MDEV: destroying\n");
258 int mdev_device_create(struct mdev_type *type, const guid_t *uuid)
261 struct mdev_device *mdev, *tmp;
262 struct mdev_parent *parent = type->parent;
263 struct mdev_driver *drv = parent->ops->device_driver;
265 mutex_lock(&mdev_list_lock);
267 /* Check for duplicate */
268 list_for_each_entry(tmp, &mdev_list, next) {
269 if (guid_equal(&tmp->uuid, uuid)) {
270 mutex_unlock(&mdev_list_lock);
275 mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
277 mutex_unlock(&mdev_list_lock);
281 device_initialize(&mdev->dev);
282 mdev->dev.parent = parent->dev;
283 mdev->dev.bus = &mdev_bus_type;
284 mdev->dev.release = mdev_device_release;
285 mdev->dev.groups = parent->ops->mdev_attr_groups;
287 /* Pairs with the put in mdev_device_release() */
288 kobject_get(&type->kobj);
290 guid_copy(&mdev->uuid, uuid);
291 list_add(&mdev->next, &mdev_list);
292 mutex_unlock(&mdev_list_lock);
294 ret = dev_set_name(&mdev->dev, "%pUl", uuid);
298 /* Check if parent unregistration has started */
299 if (!down_read_trylock(&parent->unreg_sem)) {
304 if (parent->ops->create) {
305 ret = parent->ops->create(mdev);
310 ret = device_add(&mdev->dev);
315 drv = &vfio_mdev_driver;
316 ret = device_driver_attach(&drv->driver, &mdev->dev);
320 ret = mdev_create_sysfs_files(mdev);
325 dev_dbg(&mdev->dev, "MDEV: created\n");
326 up_read(&parent->unreg_sem);
331 device_del(&mdev->dev);
333 if (parent->ops->remove)
334 parent->ops->remove(mdev);
336 up_read(&parent->unreg_sem);
338 put_device(&mdev->dev);
342 int mdev_device_remove(struct mdev_device *mdev)
344 struct mdev_device *tmp;
345 struct mdev_parent *parent = mdev->type->parent;
347 mutex_lock(&mdev_list_lock);
348 list_for_each_entry(tmp, &mdev_list, next) {
354 mutex_unlock(&mdev_list_lock);
359 mutex_unlock(&mdev_list_lock);
363 mdev->active = false;
364 mutex_unlock(&mdev_list_lock);
366 /* Check if parent unregistration has started */
367 if (!down_read_trylock(&parent->unreg_sem))
370 mdev_device_remove_common(mdev);
371 up_read(&parent->unreg_sem);
375 static int __init mdev_init(void)
379 rc = mdev_bus_register();
382 rc = mdev_register_driver(&vfio_mdev_driver);
387 mdev_bus_unregister();
391 static void __exit mdev_exit(void)
393 mdev_unregister_driver(&vfio_mdev_driver);
395 if (mdev_bus_compat_class)
396 class_compat_unregister(mdev_bus_compat_class);
398 mdev_bus_unregister();
401 module_init(mdev_init)
402 module_exit(mdev_exit)
404 MODULE_VERSION(DRIVER_VERSION);
405 MODULE_LICENSE("GPL v2");
406 MODULE_AUTHOR(DRIVER_AUTHOR);
407 MODULE_DESCRIPTION(DRIVER_DESC);