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; 146 147 /* check for mandatory ops */ 148 if (!ops || !ops->create || !ops->remove || !ops->supported_type_groups) 149 return -EINVAL; 150 151 dev = get_device(dev); 152 if (!dev) 153 return -EINVAL; 154 155 mutex_lock(&parent_list_lock); 156 157 /* Check for duplicate */ 158 parent = __find_parent_device(dev); 159 if (parent) { 160 parent = NULL; 161 ret = -EEXIST; 162 goto add_dev_err; 163 } 164 165 parent = kzalloc(sizeof(*parent), GFP_KERNEL); 166 if (!parent) { 167 ret = -ENOMEM; 168 goto add_dev_err; 169 } 170 171 kref_init(&parent->ref); 172 init_rwsem(&parent->unreg_sem); 173 174 parent->dev = dev; 175 parent->ops = ops; 176 177 if (!mdev_bus_compat_class) { 178 mdev_bus_compat_class = class_compat_register("mdev_bus"); 179 if (!mdev_bus_compat_class) { 180 ret = -ENOMEM; 181 goto add_dev_err; 182 } 183 } 184 185 ret = parent_create_sysfs_files(parent); 186 if (ret) 187 goto add_dev_err; 188 189 ret = class_compat_create_link(mdev_bus_compat_class, dev, NULL); 190 if (ret) 191 dev_warn(dev, "Failed to create compatibility class link\n"); 192 193 list_add(&parent->next, &parent_list); 194 mutex_unlock(&parent_list_lock); 195 196 dev_info(dev, "MDEV: Registered\n"); 197 return 0; 198 199 add_dev_err: 200 mutex_unlock(&parent_list_lock); 201 if (parent) 202 mdev_put_parent(parent); 203 else 204 put_device(dev); 205 return ret; 206 } 207 EXPORT_SYMBOL(mdev_register_device); 208 209 /* 210 * mdev_unregister_device : Unregister a parent device 211 * @dev: device structure representing parent device. 212 * 213 * Remove device from list of registered parent devices. Give a chance to free 214 * existing mediated devices for given device. 215 */ 216 217 void mdev_unregister_device(struct device *dev) 218 { 219 struct mdev_parent *parent; 220 221 mutex_lock(&parent_list_lock); 222 parent = __find_parent_device(dev); 223 224 if (!parent) { 225 mutex_unlock(&parent_list_lock); 226 return; 227 } 228 dev_info(dev, "MDEV: Unregistering\n"); 229 230 list_del(&parent->next); 231 mutex_unlock(&parent_list_lock); 232 233 down_write(&parent->unreg_sem); 234 235 class_compat_remove_link(mdev_bus_compat_class, dev, NULL); 236 237 device_for_each_child(dev, NULL, mdev_device_remove_cb); 238 239 parent_remove_sysfs_files(parent); 240 up_write(&parent->unreg_sem); 241 242 mdev_put_parent(parent); 243 } 244 EXPORT_SYMBOL(mdev_unregister_device); 245 246 static void mdev_device_free(struct mdev_device *mdev) 247 { 248 mutex_lock(&mdev_list_lock); 249 list_del(&mdev->next); 250 mutex_unlock(&mdev_list_lock); 251 252 dev_dbg(&mdev->dev, "MDEV: destroying\n"); 253 kfree(mdev); 254 } 255 256 static void mdev_device_release(struct device *dev) 257 { 258 struct mdev_device *mdev = to_mdev_device(dev); 259 260 mdev_device_free(mdev); 261 } 262 263 int mdev_device_create(struct kobject *kobj, 264 struct device *dev, const guid_t *uuid) 265 { 266 int ret; 267 struct mdev_device *mdev, *tmp; 268 struct mdev_parent *parent; 269 struct mdev_type *type = to_mdev_type(kobj); 270 271 parent = mdev_get_parent(type->parent); 272 if (!parent) 273 return -EINVAL; 274 275 mutex_lock(&mdev_list_lock); 276 277 /* Check for duplicate */ 278 list_for_each_entry(tmp, &mdev_list, next) { 279 if (guid_equal(&tmp->uuid, uuid)) { 280 mutex_unlock(&mdev_list_lock); 281 ret = -EEXIST; 282 goto mdev_fail; 283 } 284 } 285 286 mdev = kzalloc(sizeof(*mdev), GFP_KERNEL); 287 if (!mdev) { 288 mutex_unlock(&mdev_list_lock); 289 ret = -ENOMEM; 290 goto mdev_fail; 291 } 292 293 guid_copy(&mdev->uuid, uuid); 294 list_add(&mdev->next, &mdev_list); 295 mutex_unlock(&mdev_list_lock); 296 297 mdev->parent = parent; 298 299 /* Check if parent unregistration has started */ 300 if (!down_read_trylock(&parent->unreg_sem)) { 301 mdev_device_free(mdev); 302 ret = -ENODEV; 303 goto mdev_fail; 304 } 305 306 device_initialize(&mdev->dev); 307 mdev->dev.parent = dev; 308 mdev->dev.bus = &mdev_bus_type; 309 mdev->dev.release = mdev_device_release; 310 dev_set_name(&mdev->dev, "%pUl", uuid); 311 mdev->dev.groups = parent->ops->mdev_attr_groups; 312 mdev->type_kobj = kobj; 313 314 ret = parent->ops->create(kobj, mdev); 315 if (ret) 316 goto ops_create_fail; 317 318 ret = device_add(&mdev->dev); 319 if (ret) 320 goto add_fail; 321 322 ret = mdev_create_sysfs_files(&mdev->dev, type); 323 if (ret) 324 goto sysfs_fail; 325 326 mdev->active = true; 327 dev_dbg(&mdev->dev, "MDEV: created\n"); 328 up_read(&parent->unreg_sem); 329 330 return 0; 331 332 sysfs_fail: 333 device_del(&mdev->dev); 334 add_fail: 335 parent->ops->remove(mdev); 336 ops_create_fail: 337 up_read(&parent->unreg_sem); 338 put_device(&mdev->dev); 339 mdev_fail: 340 mdev_put_parent(parent); 341 return ret; 342 } 343 344 int mdev_device_remove(struct device *dev) 345 { 346 struct mdev_device *mdev, *tmp; 347 struct mdev_parent *parent; 348 349 mdev = to_mdev_device(dev); 350 351 mutex_lock(&mdev_list_lock); 352 list_for_each_entry(tmp, &mdev_list, next) { 353 if (tmp == mdev) 354 break; 355 } 356 357 if (tmp != mdev) { 358 mutex_unlock(&mdev_list_lock); 359 return -ENODEV; 360 } 361 362 if (!mdev->active) { 363 mutex_unlock(&mdev_list_lock); 364 return -EAGAIN; 365 } 366 367 mdev->active = false; 368 mutex_unlock(&mdev_list_lock); 369 370 parent = mdev->parent; 371 /* Check if parent unregistration has started */ 372 if (!down_read_trylock(&parent->unreg_sem)) 373 return -ENODEV; 374 375 mdev_device_remove_common(mdev); 376 up_read(&parent->unreg_sem); 377 return 0; 378 } 379 380 int mdev_set_iommu_device(struct device *dev, struct device *iommu_device) 381 { 382 struct mdev_device *mdev = to_mdev_device(dev); 383 384 mdev->iommu_device = iommu_device; 385 386 return 0; 387 } 388 EXPORT_SYMBOL(mdev_set_iommu_device); 389 390 struct device *mdev_get_iommu_device(struct device *dev) 391 { 392 struct mdev_device *mdev = to_mdev_device(dev); 393 394 return mdev->iommu_device; 395 } 396 EXPORT_SYMBOL(mdev_get_iommu_device); 397 398 static int __init mdev_init(void) 399 { 400 return mdev_bus_register(); 401 } 402 403 static void __exit mdev_exit(void) 404 { 405 if (mdev_bus_compat_class) 406 class_compat_unregister(mdev_bus_compat_class); 407 408 mdev_bus_unregister(); 409 } 410 411 module_init(mdev_init) 412 module_exit(mdev_exit) 413 414 MODULE_VERSION(DRIVER_VERSION); 415 MODULE_LICENSE("GPL v2"); 416 MODULE_AUTHOR(DRIVER_AUTHOR); 417 MODULE_DESCRIPTION(DRIVER_DESC); 418 MODULE_SOFTDEP("post: vfio_mdev"); 419