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 /* Should be called holding parent_list_lock */ 70 static struct mdev_parent *__find_parent_device(struct device *dev) 71 { 72 struct mdev_parent *parent; 73 74 list_for_each_entry(parent, &parent_list, next) { 75 if (parent->dev == dev) 76 return parent; 77 } 78 return NULL; 79 } 80 81 static void mdev_release_parent(struct kref *kref) 82 { 83 struct mdev_parent *parent = container_of(kref, struct mdev_parent, 84 ref); 85 struct device *dev = parent->dev; 86 87 kfree(parent); 88 put_device(dev); 89 } 90 91 static 92 inline struct mdev_parent *mdev_get_parent(struct mdev_parent *parent) 93 { 94 if (parent) 95 kref_get(&parent->ref); 96 97 return parent; 98 } 99 100 static inline void mdev_put_parent(struct mdev_parent *parent) 101 { 102 if (parent) 103 kref_put(&parent->ref, mdev_release_parent); 104 } 105 106 static int mdev_device_create_ops(struct kobject *kobj, 107 struct mdev_device *mdev) 108 { 109 struct mdev_parent *parent = mdev->parent; 110 int ret; 111 112 ret = parent->ops->create(kobj, mdev); 113 if (ret) 114 return ret; 115 116 ret = sysfs_create_groups(&mdev->dev.kobj, 117 parent->ops->mdev_attr_groups); 118 if (ret) 119 parent->ops->remove(mdev); 120 121 return ret; 122 } 123 124 /* 125 * mdev_device_remove_ops gets called from sysfs's 'remove' and when parent 126 * device is being unregistered from mdev device framework. 127 * - 'force_remove' is set to 'false' when called from sysfs's 'remove' which 128 * indicates that if the mdev device is active, used by VMM or userspace 129 * application, vendor driver could return error then don't remove the device. 130 * - 'force_remove' is set to 'true' when called from mdev_unregister_device() 131 * which indicate that parent device is being removed from mdev device 132 * framework so remove mdev device forcefully. 133 */ 134 static int mdev_device_remove_ops(struct mdev_device *mdev, bool force_remove) 135 { 136 struct mdev_parent *parent = mdev->parent; 137 int ret; 138 139 /* 140 * Vendor driver can return error if VMM or userspace application is 141 * using this mdev device. 142 */ 143 ret = parent->ops->remove(mdev); 144 if (ret && !force_remove) 145 return -EBUSY; 146 147 sysfs_remove_groups(&mdev->dev.kobj, parent->ops->mdev_attr_groups); 148 return 0; 149 } 150 151 static int mdev_device_remove_cb(struct device *dev, void *data) 152 { 153 if (!dev_is_mdev(dev)) 154 return 0; 155 156 return mdev_device_remove(dev, data ? *(bool *)data : true); 157 } 158 159 /* 160 * mdev_register_device : Register a device 161 * @dev: device structure representing parent device. 162 * @ops: Parent device operation structure to be registered. 163 * 164 * Add device to list of registered parent devices. 165 * Returns a negative value on error, otherwise 0. 166 */ 167 int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops) 168 { 169 int ret; 170 struct mdev_parent *parent; 171 172 /* check for mandatory ops */ 173 if (!ops || !ops->create || !ops->remove || !ops->supported_type_groups) 174 return -EINVAL; 175 176 dev = get_device(dev); 177 if (!dev) 178 return -EINVAL; 179 180 mutex_lock(&parent_list_lock); 181 182 /* Check for duplicate */ 183 parent = __find_parent_device(dev); 184 if (parent) { 185 ret = -EEXIST; 186 goto add_dev_err; 187 } 188 189 parent = kzalloc(sizeof(*parent), GFP_KERNEL); 190 if (!parent) { 191 ret = -ENOMEM; 192 goto add_dev_err; 193 } 194 195 kref_init(&parent->ref); 196 197 parent->dev = dev; 198 parent->ops = ops; 199 200 if (!mdev_bus_compat_class) { 201 mdev_bus_compat_class = class_compat_register("mdev_bus"); 202 if (!mdev_bus_compat_class) { 203 ret = -ENOMEM; 204 goto add_dev_err; 205 } 206 } 207 208 ret = parent_create_sysfs_files(parent); 209 if (ret) 210 goto add_dev_err; 211 212 ret = class_compat_create_link(mdev_bus_compat_class, dev, NULL); 213 if (ret) 214 dev_warn(dev, "Failed to create compatibility class link\n"); 215 216 list_add(&parent->next, &parent_list); 217 mutex_unlock(&parent_list_lock); 218 219 dev_info(dev, "MDEV: Registered\n"); 220 return 0; 221 222 add_dev_err: 223 mutex_unlock(&parent_list_lock); 224 if (parent) 225 mdev_put_parent(parent); 226 else 227 put_device(dev); 228 return ret; 229 } 230 EXPORT_SYMBOL(mdev_register_device); 231 232 /* 233 * mdev_unregister_device : Unregister a parent device 234 * @dev: device structure representing parent device. 235 * 236 * Remove device from list of registered parent devices. Give a chance to free 237 * existing mediated devices for given device. 238 */ 239 240 void mdev_unregister_device(struct device *dev) 241 { 242 struct mdev_parent *parent; 243 bool force_remove = true; 244 245 mutex_lock(&parent_list_lock); 246 parent = __find_parent_device(dev); 247 248 if (!parent) { 249 mutex_unlock(&parent_list_lock); 250 return; 251 } 252 dev_info(dev, "MDEV: Unregistering\n"); 253 254 list_del(&parent->next); 255 class_compat_remove_link(mdev_bus_compat_class, dev, NULL); 256 257 device_for_each_child(dev, (void *)&force_remove, 258 mdev_device_remove_cb); 259 260 parent_remove_sysfs_files(parent); 261 262 mutex_unlock(&parent_list_lock); 263 mdev_put_parent(parent); 264 } 265 EXPORT_SYMBOL(mdev_unregister_device); 266 267 static void mdev_device_release(struct device *dev) 268 { 269 struct mdev_device *mdev = to_mdev_device(dev); 270 271 mutex_lock(&mdev_list_lock); 272 list_del(&mdev->next); 273 mutex_unlock(&mdev_list_lock); 274 275 dev_dbg(&mdev->dev, "MDEV: destroying\n"); 276 kfree(mdev); 277 } 278 279 int mdev_device_create(struct kobject *kobj, struct device *dev, uuid_le uuid) 280 { 281 int ret; 282 struct mdev_device *mdev, *tmp; 283 struct mdev_parent *parent; 284 struct mdev_type *type = to_mdev_type(kobj); 285 286 parent = mdev_get_parent(type->parent); 287 if (!parent) 288 return -EINVAL; 289 290 mutex_lock(&mdev_list_lock); 291 292 /* Check for duplicate */ 293 list_for_each_entry(tmp, &mdev_list, next) { 294 if (!uuid_le_cmp(tmp->uuid, uuid)) { 295 mutex_unlock(&mdev_list_lock); 296 ret = -EEXIST; 297 goto mdev_fail; 298 } 299 } 300 301 mdev = kzalloc(sizeof(*mdev), GFP_KERNEL); 302 if (!mdev) { 303 mutex_unlock(&mdev_list_lock); 304 ret = -ENOMEM; 305 goto mdev_fail; 306 } 307 308 memcpy(&mdev->uuid, &uuid, sizeof(uuid_le)); 309 list_add(&mdev->next, &mdev_list); 310 mutex_unlock(&mdev_list_lock); 311 312 mdev->parent = parent; 313 kref_init(&mdev->ref); 314 315 mdev->dev.parent = dev; 316 mdev->dev.bus = &mdev_bus_type; 317 mdev->dev.release = mdev_device_release; 318 dev_set_name(&mdev->dev, "%pUl", uuid.b); 319 320 ret = device_register(&mdev->dev); 321 if (ret) { 322 put_device(&mdev->dev); 323 goto mdev_fail; 324 } 325 326 ret = mdev_device_create_ops(kobj, mdev); 327 if (ret) 328 goto create_fail; 329 330 ret = mdev_create_sysfs_files(&mdev->dev, type); 331 if (ret) { 332 mdev_device_remove_ops(mdev, true); 333 goto create_fail; 334 } 335 336 mdev->type_kobj = kobj; 337 mdev->active = true; 338 dev_dbg(&mdev->dev, "MDEV: created\n"); 339 340 return 0; 341 342 create_fail: 343 device_unregister(&mdev->dev); 344 mdev_fail: 345 mdev_put_parent(parent); 346 return ret; 347 } 348 349 int mdev_device_remove(struct device *dev, bool force_remove) 350 { 351 struct mdev_device *mdev, *tmp; 352 struct mdev_parent *parent; 353 struct mdev_type *type; 354 int ret; 355 356 mdev = to_mdev_device(dev); 357 358 mutex_lock(&mdev_list_lock); 359 list_for_each_entry(tmp, &mdev_list, next) { 360 if (tmp == mdev) 361 break; 362 } 363 364 if (tmp != mdev) { 365 mutex_unlock(&mdev_list_lock); 366 return -ENODEV; 367 } 368 369 if (!mdev->active) { 370 mutex_unlock(&mdev_list_lock); 371 return -EAGAIN; 372 } 373 374 mdev->active = false; 375 mutex_unlock(&mdev_list_lock); 376 377 type = to_mdev_type(mdev->type_kobj); 378 parent = mdev->parent; 379 380 ret = mdev_device_remove_ops(mdev, force_remove); 381 if (ret) { 382 mdev->active = true; 383 return ret; 384 } 385 386 mdev_remove_sysfs_files(dev, type); 387 device_unregister(dev); 388 mdev_put_parent(parent); 389 390 return 0; 391 } 392 393 static int __init mdev_init(void) 394 { 395 return mdev_bus_register(); 396 } 397 398 static void __exit mdev_exit(void) 399 { 400 if (mdev_bus_compat_class) 401 class_compat_unregister(mdev_bus_compat_class); 402 403 mdev_bus_unregister(); 404 } 405 406 module_init(mdev_init) 407 module_exit(mdev_exit) 408 409 MODULE_VERSION(DRIVER_VERSION); 410 MODULE_LICENSE("GPL v2"); 411 MODULE_AUTHOR(DRIVER_AUTHOR); 412 MODULE_DESCRIPTION(DRIVER_DESC); 413 MODULE_SOFTDEP("post: vfio_mdev"); 414