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 const guid_t *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 inline struct mdev_parent *mdev_get_parent(struct mdev_parent *parent) 92 { 93 if (parent) 94 kref_get(&parent->ref); 95 96 return parent; 97 } 98 99 static inline void mdev_put_parent(struct mdev_parent *parent) 100 { 101 if (parent) 102 kref_put(&parent->ref, mdev_release_parent); 103 } 104 105 static int mdev_device_create_ops(struct kobject *kobj, 106 struct mdev_device *mdev) 107 { 108 struct mdev_parent *parent = mdev->parent; 109 int ret; 110 111 ret = parent->ops->create(kobj, mdev); 112 if (ret) 113 return ret; 114 115 ret = sysfs_create_groups(&mdev->dev.kobj, 116 parent->ops->mdev_attr_groups); 117 if (ret) 118 parent->ops->remove(mdev); 119 120 return ret; 121 } 122 123 /* 124 * mdev_device_remove_ops gets called from sysfs's 'remove' and when parent 125 * device is being unregistered from mdev device framework. 126 * - 'force_remove' is set to 'false' when called from sysfs's 'remove' which 127 * indicates that if the mdev device is active, used by VMM or userspace 128 * application, vendor driver could return error then don't remove the device. 129 * - 'force_remove' is set to 'true' when called from mdev_unregister_device() 130 * which indicate that parent device is being removed from mdev device 131 * framework so remove mdev device forcefully. 132 */ 133 static int mdev_device_remove_ops(struct mdev_device *mdev, bool force_remove) 134 { 135 struct mdev_parent *parent = mdev->parent; 136 int ret; 137 138 /* 139 * Vendor driver can return error if VMM or userspace application is 140 * using this mdev device. 141 */ 142 ret = parent->ops->remove(mdev); 143 if (ret && !force_remove) 144 return -EBUSY; 145 146 sysfs_remove_groups(&mdev->dev.kobj, parent->ops->mdev_attr_groups); 147 return 0; 148 } 149 150 static int mdev_device_remove_cb(struct device *dev, void *data) 151 { 152 if (!dev_is_mdev(dev)) 153 return 0; 154 155 return mdev_device_remove(dev, data ? *(bool *)data : true); 156 } 157 158 /* 159 * mdev_register_device : Register a device 160 * @dev: device structure representing parent device. 161 * @ops: Parent device operation structure to be registered. 162 * 163 * Add device to list of registered parent devices. 164 * Returns a negative value on error, otherwise 0. 165 */ 166 int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops) 167 { 168 int ret; 169 struct mdev_parent *parent; 170 171 /* check for mandatory ops */ 172 if (!ops || !ops->create || !ops->remove || !ops->supported_type_groups) 173 return -EINVAL; 174 175 dev = get_device(dev); 176 if (!dev) 177 return -EINVAL; 178 179 mutex_lock(&parent_list_lock); 180 181 /* Check for duplicate */ 182 parent = __find_parent_device(dev); 183 if (parent) { 184 ret = -EEXIST; 185 goto add_dev_err; 186 } 187 188 parent = kzalloc(sizeof(*parent), GFP_KERNEL); 189 if (!parent) { 190 ret = -ENOMEM; 191 goto add_dev_err; 192 } 193 194 kref_init(&parent->ref); 195 196 parent->dev = dev; 197 parent->ops = ops; 198 199 if (!mdev_bus_compat_class) { 200 mdev_bus_compat_class = class_compat_register("mdev_bus"); 201 if (!mdev_bus_compat_class) { 202 ret = -ENOMEM; 203 goto add_dev_err; 204 } 205 } 206 207 ret = parent_create_sysfs_files(parent); 208 if (ret) 209 goto add_dev_err; 210 211 ret = class_compat_create_link(mdev_bus_compat_class, dev, NULL); 212 if (ret) 213 dev_warn(dev, "Failed to create compatibility class link\n"); 214 215 list_add(&parent->next, &parent_list); 216 mutex_unlock(&parent_list_lock); 217 218 dev_info(dev, "MDEV: Registered\n"); 219 return 0; 220 221 add_dev_err: 222 mutex_unlock(&parent_list_lock); 223 if (parent) 224 mdev_put_parent(parent); 225 else 226 put_device(dev); 227 return ret; 228 } 229 EXPORT_SYMBOL(mdev_register_device); 230 231 /* 232 * mdev_unregister_device : Unregister a parent device 233 * @dev: device structure representing parent device. 234 * 235 * Remove device from list of registered parent devices. Give a chance to free 236 * existing mediated devices for given device. 237 */ 238 239 void mdev_unregister_device(struct device *dev) 240 { 241 struct mdev_parent *parent; 242 bool force_remove = true; 243 244 mutex_lock(&parent_list_lock); 245 parent = __find_parent_device(dev); 246 247 if (!parent) { 248 mutex_unlock(&parent_list_lock); 249 return; 250 } 251 dev_info(dev, "MDEV: Unregistering\n"); 252 253 list_del(&parent->next); 254 class_compat_remove_link(mdev_bus_compat_class, dev, NULL); 255 256 device_for_each_child(dev, (void *)&force_remove, 257 mdev_device_remove_cb); 258 259 parent_remove_sysfs_files(parent); 260 261 mutex_unlock(&parent_list_lock); 262 mdev_put_parent(parent); 263 } 264 EXPORT_SYMBOL(mdev_unregister_device); 265 266 static void mdev_device_release(struct device *dev) 267 { 268 struct mdev_device *mdev = to_mdev_device(dev); 269 270 mutex_lock(&mdev_list_lock); 271 list_del(&mdev->next); 272 mutex_unlock(&mdev_list_lock); 273 274 dev_dbg(&mdev->dev, "MDEV: destroying\n"); 275 kfree(mdev); 276 } 277 278 int mdev_device_create(struct kobject *kobj, 279 struct device *dev, const guid_t *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 (guid_equal(&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 guid_copy(&mdev->uuid, uuid); 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); 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