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 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 ret; 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 mdev_device_remove(dev, true); 154 155 return 0; 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 parent = NULL; 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; 243 244 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, NULL, mdev_device_remove_cb); 257 258 parent_remove_sysfs_files(parent); 259 260 mutex_unlock(&parent_list_lock); 261 mdev_put_parent(parent); 262 } 263 EXPORT_SYMBOL(mdev_unregister_device); 264 265 static void mdev_device_release(struct device *dev) 266 { 267 struct mdev_device *mdev = to_mdev_device(dev); 268 269 mutex_lock(&mdev_list_lock); 270 list_del(&mdev->next); 271 mutex_unlock(&mdev_list_lock); 272 273 dev_dbg(&mdev->dev, "MDEV: destroying\n"); 274 kfree(mdev); 275 } 276 277 int mdev_device_create(struct kobject *kobj, 278 struct device *dev, const guid_t *uuid) 279 { 280 int ret; 281 struct mdev_device *mdev, *tmp; 282 struct mdev_parent *parent; 283 struct mdev_type *type = to_mdev_type(kobj); 284 285 parent = mdev_get_parent(type->parent); 286 if (!parent) 287 return -EINVAL; 288 289 mutex_lock(&mdev_list_lock); 290 291 /* Check for duplicate */ 292 list_for_each_entry(tmp, &mdev_list, next) { 293 if (guid_equal(&tmp->uuid, uuid)) { 294 mutex_unlock(&mdev_list_lock); 295 ret = -EEXIST; 296 goto mdev_fail; 297 } 298 } 299 300 mdev = kzalloc(sizeof(*mdev), GFP_KERNEL); 301 if (!mdev) { 302 mutex_unlock(&mdev_list_lock); 303 ret = -ENOMEM; 304 goto mdev_fail; 305 } 306 307 guid_copy(&mdev->uuid, uuid); 308 list_add(&mdev->next, &mdev_list); 309 mutex_unlock(&mdev_list_lock); 310 311 mdev->parent = parent; 312 313 mdev->dev.parent = dev; 314 mdev->dev.bus = &mdev_bus_type; 315 mdev->dev.release = mdev_device_release; 316 dev_set_name(&mdev->dev, "%pUl", uuid); 317 318 ret = device_register(&mdev->dev); 319 if (ret) { 320 put_device(&mdev->dev); 321 goto mdev_fail; 322 } 323 324 ret = mdev_device_create_ops(kobj, mdev); 325 if (ret) 326 goto create_fail; 327 328 ret = mdev_create_sysfs_files(&mdev->dev, type); 329 if (ret) { 330 mdev_device_remove_ops(mdev, true); 331 goto create_fail; 332 } 333 334 mdev->type_kobj = kobj; 335 mdev->active = true; 336 dev_dbg(&mdev->dev, "MDEV: created\n"); 337 338 return 0; 339 340 create_fail: 341 device_unregister(&mdev->dev); 342 mdev_fail: 343 mdev_put_parent(parent); 344 return ret; 345 } 346 347 int mdev_device_remove(struct device *dev, bool force_remove) 348 { 349 struct mdev_device *mdev, *tmp; 350 struct mdev_parent *parent; 351 struct mdev_type *type; 352 int ret; 353 354 mdev = to_mdev_device(dev); 355 356 mutex_lock(&mdev_list_lock); 357 list_for_each_entry(tmp, &mdev_list, next) { 358 if (tmp == mdev) 359 break; 360 } 361 362 if (tmp != mdev) { 363 mutex_unlock(&mdev_list_lock); 364 return -ENODEV; 365 } 366 367 if (!mdev->active) { 368 mutex_unlock(&mdev_list_lock); 369 return -EAGAIN; 370 } 371 372 mdev->active = false; 373 mutex_unlock(&mdev_list_lock); 374 375 type = to_mdev_type(mdev->type_kobj); 376 parent = mdev->parent; 377 378 ret = mdev_device_remove_ops(mdev, force_remove); 379 if (ret) { 380 mdev->active = true; 381 return ret; 382 } 383 384 mdev_remove_sysfs_files(dev, type); 385 device_unregister(dev); 386 mdev_put_parent(parent); 387 388 return 0; 389 } 390 391 int mdev_set_iommu_device(struct device *dev, struct device *iommu_device) 392 { 393 struct mdev_device *mdev = to_mdev_device(dev); 394 395 mdev->iommu_device = iommu_device; 396 397 return 0; 398 } 399 EXPORT_SYMBOL(mdev_set_iommu_device); 400 401 struct device *mdev_get_iommu_device(struct device *dev) 402 { 403 struct mdev_device *mdev = to_mdev_device(dev); 404 405 return mdev->iommu_device; 406 } 407 EXPORT_SYMBOL(mdev_get_iommu_device); 408 409 static int __init mdev_init(void) 410 { 411 return mdev_bus_register(); 412 } 413 414 static void __exit mdev_exit(void) 415 { 416 if (mdev_bus_compat_class) 417 class_compat_unregister(mdev_bus_compat_class); 418 419 mdev_bus_unregister(); 420 } 421 422 module_init(mdev_init) 423 module_exit(mdev_exit) 424 425 MODULE_VERSION(DRIVER_VERSION); 426 MODULE_LICENSE("GPL v2"); 427 MODULE_AUTHOR(DRIVER_AUTHOR); 428 MODULE_DESCRIPTION(DRIVER_DESC); 429 MODULE_SOFTDEP("post: vfio_mdev"); 430