1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Mediated device Core Driver
4 *
5 * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
6 * Author: Neo Jia <cjia@nvidia.com>
7 * Kirti Wankhede <kwankhede@nvidia.com>
8 */
9
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>
16
17 #include "mdev_private.h"
18
19 #define DRIVER_VERSION "0.1"
20 #define DRIVER_AUTHOR "NVIDIA Corporation"
21 #define DRIVER_DESC "Mediated device Core Driver"
22
23 static LIST_HEAD(parent_list);
24 static DEFINE_MUTEX(parent_list_lock);
25 static struct class_compat *mdev_bus_compat_class;
26
27 static LIST_HEAD(mdev_list);
28 static DEFINE_MUTEX(mdev_list_lock);
29
mdev_parent_dev(struct mdev_device * mdev)30 struct device *mdev_parent_dev(struct mdev_device *mdev)
31 {
32 return mdev->type->parent->dev;
33 }
34 EXPORT_SYMBOL(mdev_parent_dev);
35
36 /*
37 * Return the index in supported_type_groups that this mdev_device was created
38 * from.
39 */
mdev_get_type_group_id(struct mdev_device * mdev)40 unsigned int mdev_get_type_group_id(struct mdev_device *mdev)
41 {
42 return mdev->type->type_group_id;
43 }
44 EXPORT_SYMBOL(mdev_get_type_group_id);
45
46 /*
47 * Used in mdev_type_attribute sysfs functions to return the index in the
48 * supported_type_groups that the sysfs is called from.
49 */
mtype_get_type_group_id(struct mdev_type * mtype)50 unsigned int mtype_get_type_group_id(struct mdev_type *mtype)
51 {
52 return mtype->type_group_id;
53 }
54 EXPORT_SYMBOL(mtype_get_type_group_id);
55
56 /*
57 * Used in mdev_type_attribute sysfs functions to return the parent struct
58 * device
59 */
mtype_get_parent_dev(struct mdev_type * mtype)60 struct device *mtype_get_parent_dev(struct mdev_type *mtype)
61 {
62 return mtype->parent->dev;
63 }
64 EXPORT_SYMBOL(mtype_get_parent_dev);
65
66 /* Should be called holding parent_list_lock */
__find_parent_device(struct device * dev)67 static struct mdev_parent *__find_parent_device(struct device *dev)
68 {
69 struct mdev_parent *parent;
70
71 list_for_each_entry(parent, &parent_list, next) {
72 if (parent->dev == dev)
73 return parent;
74 }
75 return NULL;
76 }
77
mdev_release_parent(struct kref * kref)78 void mdev_release_parent(struct kref *kref)
79 {
80 struct mdev_parent *parent = container_of(kref, struct mdev_parent,
81 ref);
82 struct device *dev = parent->dev;
83
84 kfree(parent);
85 put_device(dev);
86 }
87
88 /* Caller must hold parent unreg_sem read or write lock */
mdev_device_remove_common(struct mdev_device * mdev)89 static void mdev_device_remove_common(struct mdev_device *mdev)
90 {
91 struct mdev_parent *parent = mdev->type->parent;
92 int ret;
93
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);
99 if (ret)
100 dev_err(&mdev->dev, "Remove failed: err=%d\n", ret);
101 }
102
103 /* Balances with device_initialize() */
104 put_device(&mdev->dev);
105 }
106
mdev_device_remove_cb(struct device * dev,void * data)107 static int mdev_device_remove_cb(struct device *dev, void *data)
108 {
109 struct mdev_device *mdev = mdev_from_dev(dev);
110
111 if (mdev)
112 mdev_device_remove_common(mdev);
113 return 0;
114 }
115
116 /*
117 * mdev_register_device : Register a device
118 * @dev: device structure representing parent device.
119 * @ops: Parent device operation structure to be registered.
120 *
121 * Add device to list of registered parent devices.
122 * Returns a negative value on error, otherwise 0.
123 */
mdev_register_device(struct device * dev,const struct mdev_parent_ops * ops)124 int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops)
125 {
126 int ret;
127 struct mdev_parent *parent;
128 char *env_string = "MDEV_STATE=registered";
129 char *envp[] = { env_string, NULL };
130
131 /* check for mandatory ops */
132 if (!ops || !ops->supported_type_groups)
133 return -EINVAL;
134 if (!ops->device_driver && (!ops->create || !ops->remove))
135 return -EINVAL;
136
137 dev = get_device(dev);
138 if (!dev)
139 return -EINVAL;
140
141 mutex_lock(&parent_list_lock);
142
143 /* Check for duplicate */
144 parent = __find_parent_device(dev);
145 if (parent) {
146 parent = NULL;
147 ret = -EEXIST;
148 goto add_dev_err;
149 }
150
151 parent = kzalloc(sizeof(*parent), GFP_KERNEL);
152 if (!parent) {
153 ret = -ENOMEM;
154 goto add_dev_err;
155 }
156
157 kref_init(&parent->ref);
158 init_rwsem(&parent->unreg_sem);
159
160 parent->dev = dev;
161 parent->ops = ops;
162
163 if (!mdev_bus_compat_class) {
164 mdev_bus_compat_class = class_compat_register("mdev_bus");
165 if (!mdev_bus_compat_class) {
166 ret = -ENOMEM;
167 goto add_dev_err;
168 }
169 }
170
171 ret = parent_create_sysfs_files(parent);
172 if (ret)
173 goto add_dev_err;
174
175 ret = class_compat_create_link(mdev_bus_compat_class, dev, NULL);
176 if (ret)
177 dev_warn(dev, "Failed to create compatibility class link\n");
178
179 list_add(&parent->next, &parent_list);
180 mutex_unlock(&parent_list_lock);
181
182 dev_info(dev, "MDEV: Registered\n");
183 kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp);
184
185 return 0;
186
187 add_dev_err:
188 mutex_unlock(&parent_list_lock);
189 if (parent)
190 mdev_put_parent(parent);
191 else
192 put_device(dev);
193 return ret;
194 }
195 EXPORT_SYMBOL(mdev_register_device);
196
197 /*
198 * mdev_unregister_device : Unregister a parent device
199 * @dev: device structure representing parent device.
200 *
201 * Remove device from list of registered parent devices. Give a chance to free
202 * existing mediated devices for given device.
203 */
204
mdev_unregister_device(struct device * dev)205 void mdev_unregister_device(struct device *dev)
206 {
207 struct mdev_parent *parent;
208 char *env_string = "MDEV_STATE=unregistered";
209 char *envp[] = { env_string, NULL };
210
211 mutex_lock(&parent_list_lock);
212 parent = __find_parent_device(dev);
213
214 if (!parent) {
215 mutex_unlock(&parent_list_lock);
216 return;
217 }
218 dev_info(dev, "MDEV: Unregistering\n");
219
220 list_del(&parent->next);
221 mutex_unlock(&parent_list_lock);
222
223 down_write(&parent->unreg_sem);
224
225 class_compat_remove_link(mdev_bus_compat_class, dev, NULL);
226
227 device_for_each_child(dev, NULL, mdev_device_remove_cb);
228
229 parent_remove_sysfs_files(parent);
230 up_write(&parent->unreg_sem);
231
232 mdev_put_parent(parent);
233
234 /* We still have the caller's reference to use for the uevent */
235 kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp);
236 }
237 EXPORT_SYMBOL(mdev_unregister_device);
238
mdev_device_release(struct device * dev)239 static void mdev_device_release(struct device *dev)
240 {
241 struct mdev_device *mdev = to_mdev_device(dev);
242
243 /* Pairs with the get in mdev_device_create() */
244 kobject_put(&mdev->type->kobj);
245
246 mutex_lock(&mdev_list_lock);
247 list_del(&mdev->next);
248 mutex_unlock(&mdev_list_lock);
249
250 dev_dbg(&mdev->dev, "MDEV: destroying\n");
251 kfree(mdev);
252 }
253
mdev_device_create(struct mdev_type * type,const guid_t * uuid)254 int mdev_device_create(struct mdev_type *type, const guid_t *uuid)
255 {
256 int ret;
257 struct mdev_device *mdev, *tmp;
258 struct mdev_parent *parent = type->parent;
259 struct mdev_driver *drv = parent->ops->device_driver;
260
261 mutex_lock(&mdev_list_lock);
262
263 /* Check for duplicate */
264 list_for_each_entry(tmp, &mdev_list, next) {
265 if (guid_equal(&tmp->uuid, uuid)) {
266 mutex_unlock(&mdev_list_lock);
267 return -EEXIST;
268 }
269 }
270
271 mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
272 if (!mdev) {
273 mutex_unlock(&mdev_list_lock);
274 return -ENOMEM;
275 }
276
277 device_initialize(&mdev->dev);
278 mdev->dev.parent = parent->dev;
279 mdev->dev.bus = &mdev_bus_type;
280 mdev->dev.release = mdev_device_release;
281 mdev->dev.groups = parent->ops->mdev_attr_groups;
282 mdev->type = type;
283 /* Pairs with the put in mdev_device_release() */
284 kobject_get(&type->kobj);
285
286 guid_copy(&mdev->uuid, uuid);
287 list_add(&mdev->next, &mdev_list);
288 mutex_unlock(&mdev_list_lock);
289
290 ret = dev_set_name(&mdev->dev, "%pUl", uuid);
291 if (ret)
292 goto out_put_device;
293
294 /* Check if parent unregistration has started */
295 if (!down_read_trylock(&parent->unreg_sem)) {
296 ret = -ENODEV;
297 goto out_put_device;
298 }
299
300 if (parent->ops->create) {
301 ret = parent->ops->create(mdev);
302 if (ret)
303 goto out_unlock;
304 }
305
306 ret = device_add(&mdev->dev);
307 if (ret)
308 goto out_remove;
309
310 if (!drv)
311 drv = &vfio_mdev_driver;
312 ret = device_driver_attach(&drv->driver, &mdev->dev);
313 if (ret)
314 goto out_del;
315
316 ret = mdev_create_sysfs_files(mdev);
317 if (ret)
318 goto out_del;
319
320 mdev->active = true;
321 dev_dbg(&mdev->dev, "MDEV: created\n");
322 up_read(&parent->unreg_sem);
323
324 return 0;
325
326 out_del:
327 device_del(&mdev->dev);
328 out_remove:
329 if (parent->ops->remove)
330 parent->ops->remove(mdev);
331 out_unlock:
332 up_read(&parent->unreg_sem);
333 out_put_device:
334 put_device(&mdev->dev);
335 return ret;
336 }
337
mdev_device_remove(struct mdev_device * mdev)338 int mdev_device_remove(struct mdev_device *mdev)
339 {
340 struct mdev_device *tmp;
341 struct mdev_parent *parent = mdev->type->parent;
342
343 mutex_lock(&mdev_list_lock);
344 list_for_each_entry(tmp, &mdev_list, next) {
345 if (tmp == mdev)
346 break;
347 }
348
349 if (tmp != mdev) {
350 mutex_unlock(&mdev_list_lock);
351 return -ENODEV;
352 }
353
354 if (!mdev->active) {
355 mutex_unlock(&mdev_list_lock);
356 return -EAGAIN;
357 }
358
359 mdev->active = false;
360 mutex_unlock(&mdev_list_lock);
361
362 /* Check if parent unregistration has started */
363 if (!down_read_trylock(&parent->unreg_sem))
364 return -ENODEV;
365
366 mdev_device_remove_common(mdev);
367 up_read(&parent->unreg_sem);
368 return 0;
369 }
370
mdev_init(void)371 static int __init mdev_init(void)
372 {
373 int rc;
374
375 rc = mdev_bus_register();
376 if (rc)
377 return rc;
378 rc = mdev_register_driver(&vfio_mdev_driver);
379 if (rc)
380 goto err_bus;
381 return 0;
382 err_bus:
383 mdev_bus_unregister();
384 return rc;
385 }
386
mdev_exit(void)387 static void __exit mdev_exit(void)
388 {
389 mdev_unregister_driver(&vfio_mdev_driver);
390
391 if (mdev_bus_compat_class)
392 class_compat_unregister(mdev_bus_compat_class);
393
394 mdev_bus_unregister();
395 }
396
397 subsys_initcall(mdev_init)
398 module_exit(mdev_exit)
399
400 MODULE_VERSION(DRIVER_VERSION);
401 MODULE_LICENSE("GPL v2");
402 MODULE_AUTHOR(DRIVER_AUTHOR);
403 MODULE_DESCRIPTION(DRIVER_DESC);
404