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 30 struct device *mdev_parent_dev(struct mdev_device *mdev) 31 { 32 return mdev->parent->dev; 33 } 34 EXPORT_SYMBOL(mdev_parent_dev); 35 36 void *mdev_get_drvdata(struct mdev_device *mdev) 37 { 38 return mdev->driver_data; 39 } 40 EXPORT_SYMBOL(mdev_get_drvdata); 41 42 void mdev_set_drvdata(struct mdev_device *mdev, void *data) 43 { 44 mdev->driver_data = data; 45 } 46 EXPORT_SYMBOL(mdev_set_drvdata); 47 48 struct device *mdev_dev(struct mdev_device *mdev) 49 { 50 return &mdev->dev; 51 } 52 EXPORT_SYMBOL(mdev_dev); 53 54 struct mdev_device *mdev_from_dev(struct device *dev) 55 { 56 return dev_is_mdev(dev) ? to_mdev_device(dev) : NULL; 57 } 58 EXPORT_SYMBOL(mdev_from_dev); 59 60 const guid_t *mdev_uuid(struct mdev_device *mdev) 61 { 62 return &mdev->uuid; 63 } 64 EXPORT_SYMBOL(mdev_uuid); 65 66 /* Should be called holding parent_list_lock */ 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 78 static 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 static struct mdev_parent *mdev_get_parent(struct mdev_parent *parent) 89 { 90 if (parent) 91 kref_get(&parent->ref); 92 93 return parent; 94 } 95 96 static void mdev_put_parent(struct mdev_parent *parent) 97 { 98 if (parent) 99 kref_put(&parent->ref, mdev_release_parent); 100 } 101 102 /* Caller must hold parent unreg_sem read or write lock */ 103 static void mdev_device_remove_common(struct mdev_device *mdev) 104 { 105 struct mdev_parent *parent; 106 struct mdev_type *type; 107 int ret; 108 109 type = to_mdev_type(mdev->type_kobj); 110 mdev_remove_sysfs_files(&mdev->dev, type); 111 device_del(&mdev->dev); 112 parent = mdev->parent; 113 lockdep_assert_held(&parent->unreg_sem); 114 ret = parent->ops->remove(mdev); 115 if (ret) 116 dev_err(&mdev->dev, "Remove failed: err=%d\n", ret); 117 118 /* Balances with device_initialize() */ 119 put_device(&mdev->dev); 120 mdev_put_parent(parent); 121 } 122 123 static int mdev_device_remove_cb(struct device *dev, void *data) 124 { 125 if (dev_is_mdev(dev)) { 126 struct mdev_device *mdev; 127 128 mdev = to_mdev_device(dev); 129 mdev_device_remove_common(mdev); 130 } 131 return 0; 132 } 133 134 /* 135 * mdev_register_device : Register a device 136 * @dev: device structure representing parent device. 137 * @ops: Parent device operation structure to be registered. 138 * 139 * Add device to list of registered parent devices. 140 * Returns a negative value on error, otherwise 0. 141 */ 142 int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops) 143 { 144 int ret; 145 struct mdev_parent *parent; 146 char *env_string = "MDEV_STATE=registered"; 147 char *envp[] = { env_string, NULL }; 148 149 /* check for mandatory ops */ 150 if (!ops || !ops->create || !ops->remove || !ops->supported_type_groups) 151 return -EINVAL; 152 153 dev = get_device(dev); 154 if (!dev) 155 return -EINVAL; 156 157 /* Not mandatory, but its absence could be a problem */ 158 if (!ops->request) 159 dev_info(dev, "Driver cannot be asked to release device\n"); 160 161 mutex_lock(&parent_list_lock); 162 163 /* Check for duplicate */ 164 parent = __find_parent_device(dev); 165 if (parent) { 166 parent = NULL; 167 ret = -EEXIST; 168 goto add_dev_err; 169 } 170 171 parent = kzalloc(sizeof(*parent), GFP_KERNEL); 172 if (!parent) { 173 ret = -ENOMEM; 174 goto add_dev_err; 175 } 176 177 kref_init(&parent->ref); 178 init_rwsem(&parent->unreg_sem); 179 180 parent->dev = dev; 181 parent->ops = ops; 182 183 if (!mdev_bus_compat_class) { 184 mdev_bus_compat_class = class_compat_register("mdev_bus"); 185 if (!mdev_bus_compat_class) { 186 ret = -ENOMEM; 187 goto add_dev_err; 188 } 189 } 190 191 ret = parent_create_sysfs_files(parent); 192 if (ret) 193 goto add_dev_err; 194 195 ret = class_compat_create_link(mdev_bus_compat_class, dev, NULL); 196 if (ret) 197 dev_warn(dev, "Failed to create compatibility class link\n"); 198 199 list_add(&parent->next, &parent_list); 200 mutex_unlock(&parent_list_lock); 201 202 dev_info(dev, "MDEV: Registered\n"); 203 kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp); 204 205 return 0; 206 207 add_dev_err: 208 mutex_unlock(&parent_list_lock); 209 if (parent) 210 mdev_put_parent(parent); 211 else 212 put_device(dev); 213 return ret; 214 } 215 EXPORT_SYMBOL(mdev_register_device); 216 217 /* 218 * mdev_unregister_device : Unregister a parent device 219 * @dev: device structure representing parent device. 220 * 221 * Remove device from list of registered parent devices. Give a chance to free 222 * existing mediated devices for given device. 223 */ 224 225 void mdev_unregister_device(struct device *dev) 226 { 227 struct mdev_parent *parent; 228 char *env_string = "MDEV_STATE=unregistered"; 229 char *envp[] = { env_string, NULL }; 230 231 mutex_lock(&parent_list_lock); 232 parent = __find_parent_device(dev); 233 234 if (!parent) { 235 mutex_unlock(&parent_list_lock); 236 return; 237 } 238 dev_info(dev, "MDEV: Unregistering\n"); 239 240 list_del(&parent->next); 241 mutex_unlock(&parent_list_lock); 242 243 down_write(&parent->unreg_sem); 244 245 class_compat_remove_link(mdev_bus_compat_class, dev, NULL); 246 247 device_for_each_child(dev, NULL, mdev_device_remove_cb); 248 249 parent_remove_sysfs_files(parent); 250 up_write(&parent->unreg_sem); 251 252 mdev_put_parent(parent); 253 254 /* We still have the caller's reference to use for the uevent */ 255 kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp); 256 } 257 EXPORT_SYMBOL(mdev_unregister_device); 258 259 static void mdev_device_free(struct mdev_device *mdev) 260 { 261 mutex_lock(&mdev_list_lock); 262 list_del(&mdev->next); 263 mutex_unlock(&mdev_list_lock); 264 265 dev_dbg(&mdev->dev, "MDEV: destroying\n"); 266 kfree(mdev); 267 } 268 269 static void mdev_device_release(struct device *dev) 270 { 271 struct mdev_device *mdev = to_mdev_device(dev); 272 273 mdev_device_free(mdev); 274 } 275 276 int mdev_device_create(struct kobject *kobj, 277 struct device *dev, const guid_t *uuid) 278 { 279 int ret; 280 struct mdev_device *mdev, *tmp; 281 struct mdev_parent *parent; 282 struct mdev_type *type = to_mdev_type(kobj); 283 284 parent = mdev_get_parent(type->parent); 285 if (!parent) 286 return -EINVAL; 287 288 mutex_lock(&mdev_list_lock); 289 290 /* Check for duplicate */ 291 list_for_each_entry(tmp, &mdev_list, next) { 292 if (guid_equal(&tmp->uuid, uuid)) { 293 mutex_unlock(&mdev_list_lock); 294 ret = -EEXIST; 295 goto mdev_fail; 296 } 297 } 298 299 mdev = kzalloc(sizeof(*mdev), GFP_KERNEL); 300 if (!mdev) { 301 mutex_unlock(&mdev_list_lock); 302 ret = -ENOMEM; 303 goto mdev_fail; 304 } 305 306 guid_copy(&mdev->uuid, uuid); 307 list_add(&mdev->next, &mdev_list); 308 mutex_unlock(&mdev_list_lock); 309 310 mdev->parent = parent; 311 312 /* Check if parent unregistration has started */ 313 if (!down_read_trylock(&parent->unreg_sem)) { 314 mdev_device_free(mdev); 315 ret = -ENODEV; 316 goto mdev_fail; 317 } 318 319 device_initialize(&mdev->dev); 320 mdev->dev.parent = dev; 321 mdev->dev.bus = &mdev_bus_type; 322 mdev->dev.release = mdev_device_release; 323 dev_set_name(&mdev->dev, "%pUl", uuid); 324 mdev->dev.groups = parent->ops->mdev_attr_groups; 325 mdev->type_kobj = kobj; 326 327 ret = parent->ops->create(kobj, mdev); 328 if (ret) 329 goto ops_create_fail; 330 331 ret = device_add(&mdev->dev); 332 if (ret) 333 goto add_fail; 334 335 ret = mdev_create_sysfs_files(&mdev->dev, type); 336 if (ret) 337 goto sysfs_fail; 338 339 mdev->active = true; 340 dev_dbg(&mdev->dev, "MDEV: created\n"); 341 up_read(&parent->unreg_sem); 342 343 return 0; 344 345 sysfs_fail: 346 device_del(&mdev->dev); 347 add_fail: 348 parent->ops->remove(mdev); 349 ops_create_fail: 350 up_read(&parent->unreg_sem); 351 put_device(&mdev->dev); 352 mdev_fail: 353 mdev_put_parent(parent); 354 return ret; 355 } 356 357 int mdev_device_remove(struct device *dev) 358 { 359 struct mdev_device *mdev, *tmp; 360 struct mdev_parent *parent; 361 362 mdev = to_mdev_device(dev); 363 364 mutex_lock(&mdev_list_lock); 365 list_for_each_entry(tmp, &mdev_list, next) { 366 if (tmp == mdev) 367 break; 368 } 369 370 if (tmp != mdev) { 371 mutex_unlock(&mdev_list_lock); 372 return -ENODEV; 373 } 374 375 if (!mdev->active) { 376 mutex_unlock(&mdev_list_lock); 377 return -EAGAIN; 378 } 379 380 mdev->active = false; 381 mutex_unlock(&mdev_list_lock); 382 383 parent = mdev->parent; 384 /* Check if parent unregistration has started */ 385 if (!down_read_trylock(&parent->unreg_sem)) 386 return -ENODEV; 387 388 mdev_device_remove_common(mdev); 389 up_read(&parent->unreg_sem); 390 return 0; 391 } 392 393 int mdev_set_iommu_device(struct device *dev, struct device *iommu_device) 394 { 395 struct mdev_device *mdev = to_mdev_device(dev); 396 397 mdev->iommu_device = iommu_device; 398 399 return 0; 400 } 401 EXPORT_SYMBOL(mdev_set_iommu_device); 402 403 struct device *mdev_get_iommu_device(struct device *dev) 404 { 405 struct mdev_device *mdev = to_mdev_device(dev); 406 407 return mdev->iommu_device; 408 } 409 EXPORT_SYMBOL(mdev_get_iommu_device); 410 411 static int __init mdev_init(void) 412 { 413 return mdev_bus_register(); 414 } 415 416 static void __exit mdev_exit(void) 417 { 418 if (mdev_bus_compat_class) 419 class_compat_unregister(mdev_bus_compat_class); 420 421 mdev_bus_unregister(); 422 } 423 424 module_init(mdev_init) 425 module_exit(mdev_exit) 426 427 MODULE_VERSION(DRIVER_VERSION); 428 MODULE_LICENSE("GPL v2"); 429 MODULE_AUTHOR(DRIVER_AUTHOR); 430 MODULE_DESCRIPTION(DRIVER_DESC); 431 MODULE_SOFTDEP("post: vfio_mdev"); 432