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 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 void mdev_put_parent(struct mdev_parent *parent) 100 { 101 if (parent) 102 kref_put(&parent->ref, mdev_release_parent); 103 } 104 105 /* Caller must hold parent unreg_sem read or write lock */ 106 static void mdev_device_remove_common(struct mdev_device *mdev) 107 { 108 struct mdev_parent *parent; 109 struct mdev_type *type; 110 int ret; 111 112 type = to_mdev_type(mdev->type_kobj); 113 mdev_remove_sysfs_files(&mdev->dev, type); 114 device_del(&mdev->dev); 115 parent = mdev->parent; 116 lockdep_assert_held(&parent->unreg_sem); 117 ret = parent->ops->remove(mdev); 118 if (ret) 119 dev_err(&mdev->dev, "Remove failed: err=%d\n", ret); 120 121 /* Balances with device_initialize() */ 122 put_device(&mdev->dev); 123 mdev_put_parent(parent); 124 } 125 126 static int mdev_device_remove_cb(struct device *dev, void *data) 127 { 128 if (dev_is_mdev(dev)) { 129 struct mdev_device *mdev; 130 131 mdev = to_mdev_device(dev); 132 mdev_device_remove_common(mdev); 133 } 134 return 0; 135 } 136 137 /* 138 * mdev_register_device : Register a device 139 * @dev: device structure representing parent device. 140 * @ops: Parent device operation structure to be registered. 141 * 142 * Add device to list of registered parent devices. 143 * Returns a negative value on error, otherwise 0. 144 */ 145 int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops) 146 { 147 int ret; 148 struct mdev_parent *parent; 149 150 /* check for mandatory ops */ 151 if (!ops || !ops->create || !ops->remove || !ops->supported_type_groups) 152 return -EINVAL; 153 154 dev = get_device(dev); 155 if (!dev) 156 return -EINVAL; 157 158 mutex_lock(&parent_list_lock); 159 160 /* Check for duplicate */ 161 parent = __find_parent_device(dev); 162 if (parent) { 163 parent = NULL; 164 ret = -EEXIST; 165 goto add_dev_err; 166 } 167 168 parent = kzalloc(sizeof(*parent), GFP_KERNEL); 169 if (!parent) { 170 ret = -ENOMEM; 171 goto add_dev_err; 172 } 173 174 kref_init(&parent->ref); 175 init_rwsem(&parent->unreg_sem); 176 177 parent->dev = dev; 178 parent->ops = ops; 179 180 if (!mdev_bus_compat_class) { 181 mdev_bus_compat_class = class_compat_register("mdev_bus"); 182 if (!mdev_bus_compat_class) { 183 ret = -ENOMEM; 184 goto add_dev_err; 185 } 186 } 187 188 ret = parent_create_sysfs_files(parent); 189 if (ret) 190 goto add_dev_err; 191 192 ret = class_compat_create_link(mdev_bus_compat_class, dev, NULL); 193 if (ret) 194 dev_warn(dev, "Failed to create compatibility class link\n"); 195 196 list_add(&parent->next, &parent_list); 197 mutex_unlock(&parent_list_lock); 198 199 dev_info(dev, "MDEV: Registered\n"); 200 return 0; 201 202 add_dev_err: 203 mutex_unlock(&parent_list_lock); 204 if (parent) 205 mdev_put_parent(parent); 206 else 207 put_device(dev); 208 return ret; 209 } 210 EXPORT_SYMBOL(mdev_register_device); 211 212 /* 213 * mdev_unregister_device : Unregister a parent device 214 * @dev: device structure representing parent device. 215 * 216 * Remove device from list of registered parent devices. Give a chance to free 217 * existing mediated devices for given device. 218 */ 219 220 void mdev_unregister_device(struct device *dev) 221 { 222 struct mdev_parent *parent; 223 224 mutex_lock(&parent_list_lock); 225 parent = __find_parent_device(dev); 226 227 if (!parent) { 228 mutex_unlock(&parent_list_lock); 229 return; 230 } 231 dev_info(dev, "MDEV: Unregistering\n"); 232 233 list_del(&parent->next); 234 mutex_unlock(&parent_list_lock); 235 236 down_write(&parent->unreg_sem); 237 238 class_compat_remove_link(mdev_bus_compat_class, dev, NULL); 239 240 device_for_each_child(dev, NULL, mdev_device_remove_cb); 241 242 parent_remove_sysfs_files(parent); 243 up_write(&parent->unreg_sem); 244 245 mdev_put_parent(parent); 246 } 247 EXPORT_SYMBOL(mdev_unregister_device); 248 249 static void mdev_device_free(struct mdev_device *mdev) 250 { 251 mutex_lock(&mdev_list_lock); 252 list_del(&mdev->next); 253 mutex_unlock(&mdev_list_lock); 254 255 dev_dbg(&mdev->dev, "MDEV: destroying\n"); 256 kfree(mdev); 257 } 258 259 static void mdev_device_release(struct device *dev) 260 { 261 struct mdev_device *mdev = to_mdev_device(dev); 262 263 mdev_device_free(mdev); 264 } 265 266 int mdev_device_create(struct kobject *kobj, 267 struct device *dev, const guid_t *uuid) 268 { 269 int ret; 270 struct mdev_device *mdev, *tmp; 271 struct mdev_parent *parent; 272 struct mdev_type *type = to_mdev_type(kobj); 273 274 parent = mdev_get_parent(type->parent); 275 if (!parent) 276 return -EINVAL; 277 278 mutex_lock(&mdev_list_lock); 279 280 /* Check for duplicate */ 281 list_for_each_entry(tmp, &mdev_list, next) { 282 if (guid_equal(&tmp->uuid, uuid)) { 283 mutex_unlock(&mdev_list_lock); 284 ret = -EEXIST; 285 goto mdev_fail; 286 } 287 } 288 289 mdev = kzalloc(sizeof(*mdev), GFP_KERNEL); 290 if (!mdev) { 291 mutex_unlock(&mdev_list_lock); 292 ret = -ENOMEM; 293 goto mdev_fail; 294 } 295 296 guid_copy(&mdev->uuid, uuid); 297 list_add(&mdev->next, &mdev_list); 298 mutex_unlock(&mdev_list_lock); 299 300 mdev->parent = parent; 301 302 /* Check if parent unregistration has started */ 303 if (!down_read_trylock(&parent->unreg_sem)) { 304 mdev_device_free(mdev); 305 ret = -ENODEV; 306 goto mdev_fail; 307 } 308 309 device_initialize(&mdev->dev); 310 mdev->dev.parent = dev; 311 mdev->dev.bus = &mdev_bus_type; 312 mdev->dev.release = mdev_device_release; 313 dev_set_name(&mdev->dev, "%pUl", uuid); 314 mdev->dev.groups = parent->ops->mdev_attr_groups; 315 mdev->type_kobj = kobj; 316 317 ret = parent->ops->create(kobj, mdev); 318 if (ret) 319 goto ops_create_fail; 320 321 ret = device_add(&mdev->dev); 322 if (ret) 323 goto add_fail; 324 325 ret = mdev_create_sysfs_files(&mdev->dev, type); 326 if (ret) 327 goto sysfs_fail; 328 329 mdev->active = true; 330 dev_dbg(&mdev->dev, "MDEV: created\n"); 331 up_read(&parent->unreg_sem); 332 333 return 0; 334 335 sysfs_fail: 336 device_del(&mdev->dev); 337 add_fail: 338 parent->ops->remove(mdev); 339 ops_create_fail: 340 up_read(&parent->unreg_sem); 341 put_device(&mdev->dev); 342 mdev_fail: 343 mdev_put_parent(parent); 344 return ret; 345 } 346 347 int mdev_device_remove(struct device *dev) 348 { 349 struct mdev_device *mdev, *tmp; 350 struct mdev_parent *parent; 351 352 mdev = to_mdev_device(dev); 353 354 mutex_lock(&mdev_list_lock); 355 list_for_each_entry(tmp, &mdev_list, next) { 356 if (tmp == mdev) 357 break; 358 } 359 360 if (tmp != mdev) { 361 mutex_unlock(&mdev_list_lock); 362 return -ENODEV; 363 } 364 365 if (!mdev->active) { 366 mutex_unlock(&mdev_list_lock); 367 return -EAGAIN; 368 } 369 370 mdev->active = false; 371 mutex_unlock(&mdev_list_lock); 372 373 parent = mdev->parent; 374 /* Check if parent unregistration has started */ 375 if (!down_read_trylock(&parent->unreg_sem)) 376 return -ENODEV; 377 378 mdev_device_remove_common(mdev); 379 up_read(&parent->unreg_sem); 380 return 0; 381 } 382 383 int mdev_set_iommu_device(struct device *dev, struct device *iommu_device) 384 { 385 struct mdev_device *mdev = to_mdev_device(dev); 386 387 mdev->iommu_device = iommu_device; 388 389 return 0; 390 } 391 EXPORT_SYMBOL(mdev_set_iommu_device); 392 393 struct device *mdev_get_iommu_device(struct device *dev) 394 { 395 struct mdev_device *mdev = to_mdev_device(dev); 396 397 return mdev->iommu_device; 398 } 399 EXPORT_SYMBOL(mdev_get_iommu_device); 400 401 static int __init mdev_init(void) 402 { 403 return mdev_bus_register(); 404 } 405 406 static void __exit mdev_exit(void) 407 { 408 if (mdev_bus_compat_class) 409 class_compat_unregister(mdev_bus_compat_class); 410 411 mdev_bus_unregister(); 412 } 413 414 module_init(mdev_init) 415 module_exit(mdev_exit) 416 417 MODULE_VERSION(DRIVER_VERSION); 418 MODULE_LICENSE("GPL v2"); 419 MODULE_AUTHOR(DRIVER_AUTHOR); 420 MODULE_DESCRIPTION(DRIVER_DESC); 421 MODULE_SOFTDEP("post: vfio_mdev"); 422