1 /* 2 * Mediated device Core Driver 3 * 4 * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved. 5 * Author: Neo Jia <cjia@nvidia.com> 6 * Kirti Wankhede <kwankhede@nvidia.com> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 */ 12 13 #include <linux/module.h> 14 #include <linux/device.h> 15 #include <linux/slab.h> 16 #include <linux/uuid.h> 17 #include <linux/sysfs.h> 18 #include <linux/mdev.h> 19 20 #include "mdev_private.h" 21 22 #define DRIVER_VERSION "0.1" 23 #define DRIVER_AUTHOR "NVIDIA Corporation" 24 #define DRIVER_DESC "Mediated device Core Driver" 25 26 static LIST_HEAD(parent_list); 27 static DEFINE_MUTEX(parent_list_lock); 28 static struct class_compat *mdev_bus_compat_class; 29 30 static LIST_HEAD(mdev_list); 31 static DEFINE_MUTEX(mdev_list_lock); 32 33 struct device *mdev_parent_dev(struct mdev_device *mdev) 34 { 35 return mdev->parent->dev; 36 } 37 EXPORT_SYMBOL(mdev_parent_dev); 38 39 void *mdev_get_drvdata(struct mdev_device *mdev) 40 { 41 return mdev->driver_data; 42 } 43 EXPORT_SYMBOL(mdev_get_drvdata); 44 45 void mdev_set_drvdata(struct mdev_device *mdev, void *data) 46 { 47 mdev->driver_data = data; 48 } 49 EXPORT_SYMBOL(mdev_set_drvdata); 50 51 struct device *mdev_dev(struct mdev_device *mdev) 52 { 53 return &mdev->dev; 54 } 55 EXPORT_SYMBOL(mdev_dev); 56 57 struct mdev_device *mdev_from_dev(struct device *dev) 58 { 59 return dev_is_mdev(dev) ? to_mdev_device(dev) : NULL; 60 } 61 EXPORT_SYMBOL(mdev_from_dev); 62 63 uuid_le mdev_uuid(struct mdev_device *mdev) 64 { 65 return mdev->uuid; 66 } 67 EXPORT_SYMBOL(mdev_uuid); 68 69 static int _find_mdev_device(struct device *dev, void *data) 70 { 71 struct mdev_device *mdev; 72 73 if (!dev_is_mdev(dev)) 74 return 0; 75 76 mdev = to_mdev_device(dev); 77 78 if (uuid_le_cmp(mdev->uuid, *(uuid_le *)data) == 0) 79 return 1; 80 81 return 0; 82 } 83 84 static bool mdev_device_exist(struct mdev_parent *parent, uuid_le uuid) 85 { 86 struct device *dev; 87 88 dev = device_find_child(parent->dev, &uuid, _find_mdev_device); 89 if (dev) { 90 put_device(dev); 91 return true; 92 } 93 94 return false; 95 } 96 97 /* Should be called holding parent_list_lock */ 98 static struct mdev_parent *__find_parent_device(struct device *dev) 99 { 100 struct mdev_parent *parent; 101 102 list_for_each_entry(parent, &parent_list, next) { 103 if (parent->dev == dev) 104 return parent; 105 } 106 return NULL; 107 } 108 109 static void mdev_release_parent(struct kref *kref) 110 { 111 struct mdev_parent *parent = container_of(kref, struct mdev_parent, 112 ref); 113 struct device *dev = parent->dev; 114 115 kfree(parent); 116 put_device(dev); 117 } 118 119 static 120 inline struct mdev_parent *mdev_get_parent(struct mdev_parent *parent) 121 { 122 if (parent) 123 kref_get(&parent->ref); 124 125 return parent; 126 } 127 128 static inline void mdev_put_parent(struct mdev_parent *parent) 129 { 130 if (parent) 131 kref_put(&parent->ref, mdev_release_parent); 132 } 133 134 static int mdev_device_create_ops(struct kobject *kobj, 135 struct mdev_device *mdev) 136 { 137 struct mdev_parent *parent = mdev->parent; 138 int ret; 139 140 ret = parent->ops->create(kobj, mdev); 141 if (ret) 142 return ret; 143 144 ret = sysfs_create_groups(&mdev->dev.kobj, 145 parent->ops->mdev_attr_groups); 146 if (ret) 147 parent->ops->remove(mdev); 148 149 return ret; 150 } 151 152 /* 153 * mdev_device_remove_ops gets called from sysfs's 'remove' and when parent 154 * device is being unregistered from mdev device framework. 155 * - 'force_remove' is set to 'false' when called from sysfs's 'remove' which 156 * indicates that if the mdev device is active, used by VMM or userspace 157 * application, vendor driver could return error then don't remove the device. 158 * - 'force_remove' is set to 'true' when called from mdev_unregister_device() 159 * which indicate that parent device is being removed from mdev device 160 * framework so remove mdev device forcefully. 161 */ 162 static int mdev_device_remove_ops(struct mdev_device *mdev, bool force_remove) 163 { 164 struct mdev_parent *parent = mdev->parent; 165 int ret; 166 167 /* 168 * Vendor driver can return error if VMM or userspace application is 169 * using this mdev device. 170 */ 171 ret = parent->ops->remove(mdev); 172 if (ret && !force_remove) 173 return -EBUSY; 174 175 sysfs_remove_groups(&mdev->dev.kobj, parent->ops->mdev_attr_groups); 176 return 0; 177 } 178 179 static int mdev_device_remove_cb(struct device *dev, void *data) 180 { 181 if (!dev_is_mdev(dev)) 182 return 0; 183 184 return mdev_device_remove(dev, data ? *(bool *)data : true); 185 } 186 187 /* 188 * mdev_register_device : Register a device 189 * @dev: device structure representing parent device. 190 * @ops: Parent device operation structure to be registered. 191 * 192 * Add device to list of registered parent devices. 193 * Returns a negative value on error, otherwise 0. 194 */ 195 int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops) 196 { 197 int ret; 198 struct mdev_parent *parent; 199 200 /* check for mandatory ops */ 201 if (!ops || !ops->create || !ops->remove || !ops->supported_type_groups) 202 return -EINVAL; 203 204 dev = get_device(dev); 205 if (!dev) 206 return -EINVAL; 207 208 mutex_lock(&parent_list_lock); 209 210 /* Check for duplicate */ 211 parent = __find_parent_device(dev); 212 if (parent) { 213 ret = -EEXIST; 214 goto add_dev_err; 215 } 216 217 parent = kzalloc(sizeof(*parent), GFP_KERNEL); 218 if (!parent) { 219 ret = -ENOMEM; 220 goto add_dev_err; 221 } 222 223 kref_init(&parent->ref); 224 mutex_init(&parent->lock); 225 226 parent->dev = dev; 227 parent->ops = ops; 228 229 if (!mdev_bus_compat_class) { 230 mdev_bus_compat_class = class_compat_register("mdev_bus"); 231 if (!mdev_bus_compat_class) { 232 ret = -ENOMEM; 233 goto add_dev_err; 234 } 235 } 236 237 ret = parent_create_sysfs_files(parent); 238 if (ret) 239 goto add_dev_err; 240 241 ret = class_compat_create_link(mdev_bus_compat_class, dev, NULL); 242 if (ret) 243 dev_warn(dev, "Failed to create compatibility class link\n"); 244 245 list_add(&parent->next, &parent_list); 246 mutex_unlock(&parent_list_lock); 247 248 dev_info(dev, "MDEV: Registered\n"); 249 return 0; 250 251 add_dev_err: 252 mutex_unlock(&parent_list_lock); 253 if (parent) 254 mdev_put_parent(parent); 255 else 256 put_device(dev); 257 return ret; 258 } 259 EXPORT_SYMBOL(mdev_register_device); 260 261 /* 262 * mdev_unregister_device : Unregister a parent device 263 * @dev: device structure representing parent device. 264 * 265 * Remove device from list of registered parent devices. Give a chance to free 266 * existing mediated devices for given device. 267 */ 268 269 void mdev_unregister_device(struct device *dev) 270 { 271 struct mdev_parent *parent; 272 bool force_remove = true; 273 274 mutex_lock(&parent_list_lock); 275 parent = __find_parent_device(dev); 276 277 if (!parent) { 278 mutex_unlock(&parent_list_lock); 279 return; 280 } 281 dev_info(dev, "MDEV: Unregistering\n"); 282 283 list_del(&parent->next); 284 class_compat_remove_link(mdev_bus_compat_class, dev, NULL); 285 286 device_for_each_child(dev, (void *)&force_remove, 287 mdev_device_remove_cb); 288 289 parent_remove_sysfs_files(parent); 290 291 mutex_unlock(&parent_list_lock); 292 mdev_put_parent(parent); 293 } 294 EXPORT_SYMBOL(mdev_unregister_device); 295 296 static void mdev_device_release(struct device *dev) 297 { 298 struct mdev_device *mdev = to_mdev_device(dev); 299 300 dev_dbg(&mdev->dev, "MDEV: destroying\n"); 301 kfree(mdev); 302 } 303 304 int mdev_device_create(struct kobject *kobj, struct device *dev, uuid_le uuid) 305 { 306 int ret; 307 struct mdev_device *mdev; 308 struct mdev_parent *parent; 309 struct mdev_type *type = to_mdev_type(kobj); 310 311 parent = mdev_get_parent(type->parent); 312 if (!parent) 313 return -EINVAL; 314 315 mutex_lock(&parent->lock); 316 317 /* Check for duplicate */ 318 if (mdev_device_exist(parent, uuid)) { 319 ret = -EEXIST; 320 goto create_err; 321 } 322 323 mdev = kzalloc(sizeof(*mdev), GFP_KERNEL); 324 if (!mdev) { 325 ret = -ENOMEM; 326 goto create_err; 327 } 328 329 memcpy(&mdev->uuid, &uuid, sizeof(uuid_le)); 330 mdev->parent = parent; 331 kref_init(&mdev->ref); 332 333 mdev->dev.parent = dev; 334 mdev->dev.bus = &mdev_bus_type; 335 mdev->dev.release = mdev_device_release; 336 dev_set_name(&mdev->dev, "%pUl", uuid.b); 337 338 ret = device_register(&mdev->dev); 339 if (ret) { 340 put_device(&mdev->dev); 341 goto create_err; 342 } 343 344 ret = mdev_device_create_ops(kobj, mdev); 345 if (ret) 346 goto create_failed; 347 348 ret = mdev_create_sysfs_files(&mdev->dev, type); 349 if (ret) { 350 mdev_device_remove_ops(mdev, true); 351 goto create_failed; 352 } 353 354 mdev->type_kobj = kobj; 355 dev_dbg(&mdev->dev, "MDEV: created\n"); 356 357 mutex_unlock(&parent->lock); 358 359 mutex_lock(&mdev_list_lock); 360 list_add(&mdev->next, &mdev_list); 361 mutex_unlock(&mdev_list_lock); 362 363 return ret; 364 365 create_failed: 366 device_unregister(&mdev->dev); 367 368 create_err: 369 mutex_unlock(&parent->lock); 370 mdev_put_parent(parent); 371 return ret; 372 } 373 374 int mdev_device_remove(struct device *dev, bool force_remove) 375 { 376 struct mdev_device *mdev, *tmp; 377 struct mdev_parent *parent; 378 struct mdev_type *type; 379 int ret; 380 bool found = false; 381 382 mdev = to_mdev_device(dev); 383 384 mutex_lock(&mdev_list_lock); 385 list_for_each_entry(tmp, &mdev_list, next) { 386 if (tmp == mdev) { 387 found = true; 388 break; 389 } 390 } 391 392 if (found) 393 list_del(&mdev->next); 394 395 mutex_unlock(&mdev_list_lock); 396 397 if (!found) 398 return -ENODEV; 399 400 type = to_mdev_type(mdev->type_kobj); 401 parent = mdev->parent; 402 mutex_lock(&parent->lock); 403 404 ret = mdev_device_remove_ops(mdev, force_remove); 405 if (ret) { 406 mutex_unlock(&parent->lock); 407 408 mutex_lock(&mdev_list_lock); 409 list_add(&mdev->next, &mdev_list); 410 mutex_unlock(&mdev_list_lock); 411 412 return ret; 413 } 414 415 mdev_remove_sysfs_files(dev, type); 416 device_unregister(dev); 417 mutex_unlock(&parent->lock); 418 mdev_put_parent(parent); 419 420 return 0; 421 } 422 423 static int __init mdev_init(void) 424 { 425 int ret; 426 427 ret = mdev_bus_register(); 428 429 /* 430 * Attempt to load known vfio_mdev. This gives us a working environment 431 * without the user needing to explicitly load vfio_mdev driver. 432 */ 433 if (!ret) 434 request_module_nowait("vfio_mdev"); 435 436 return ret; 437 } 438 439 static void __exit mdev_exit(void) 440 { 441 if (mdev_bus_compat_class) 442 class_compat_unregister(mdev_bus_compat_class); 443 444 mdev_bus_unregister(); 445 } 446 447 module_init(mdev_init) 448 module_exit(mdev_exit) 449 450 MODULE_VERSION(DRIVER_VERSION); 451 MODULE_LICENSE("GPL v2"); 452 MODULE_AUTHOR(DRIVER_AUTHOR); 453 MODULE_DESCRIPTION(DRIVER_DESC); 454