drivers/vfio/mdev/mdev_core.c

   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 uuid_le mdev_uuid(struct mdev_device *mdev)
  64 {
  65         return mdev->uuid;
  66 }
  67 EXPORT_SYMBOL(mdev_uuid);
  68
  69 static int _find_mdev_device(struct device *dev, void *data)
  70 {
  71         struct mdev_device *mdev;
  72
  73         if (!dev_is_mdev(dev))
  74                 return 0;
  75
  76         mdev = to_mdev_device(dev);
  77
  78         if (uuid_le_cmp(mdev->uuid, *(uuid_le *)data) == 0)
  79                 return 1;
  80
  81         return 0;
  82 }
  83
  84 static bool mdev_device_exist(struct mdev_parent *parent, uuid_le uuid)
  85 {
  86         struct device *dev;
  87
  88         dev = device_find_child(parent->dev, &uuid, _find_mdev_device);
  89         if (dev) {
  90                 put_device(dev);
  91                 return true;
  92         }
  93
  94         return false;
  95 }
  96
  97 /* Should be called holding parent_list_lock */
  98 static struct mdev_parent *__find_parent_device(struct device *dev)
  99 {
 100         struct mdev_parent *parent;
 101
 102         list_for_each_entry(parent, &parent_list, next) {
 103                 if (parent->dev == dev)
 104                         return parent;
 105         }
 106         return NULL;
 107 }
 108
 109 static void mdev_release_parent(struct kref *kref)
 110 {
 111         struct mdev_parent *parent = container_of(kref, struct mdev_parent,
 112                                                   ref);
 113         struct device *dev = parent->dev;
 114
 115         kfree(parent);
 116         put_device(dev);
 117 }
 118
 119 static
 120 inline struct mdev_parent *mdev_get_parent(struct mdev_parent *parent)
 121 {
 122         if (parent)
 123                 kref_get(&parent->ref);
 124
 125         return parent;
 126 }
 127
 128 static inline void mdev_put_parent(struct mdev_parent *parent)
 129 {
 130         if (parent)
 131                 kref_put(&parent->ref, mdev_release_parent);
 132 }
 133
 134 static int mdev_device_create_ops(struct kobject *kobj,
 135                                   struct mdev_device *mdev)
 136 {
 137         struct mdev_parent *parent = mdev->parent;
 138         int ret;
 139
 140         ret = parent->ops->create(kobj, mdev);
 141         if (ret)
 142                 return ret;
 143
 144         ret = sysfs_create_groups(&mdev->dev.kobj,
 145                                   parent->ops->mdev_attr_groups);
 146         if (ret)
 147                 parent->ops->remove(mdev);
 148
 149         return ret;
 150 }
 151
 152 /*
 153  * mdev_device_remove_ops gets called from sysfs's 'remove' and when parent
 154  * device is being unregistered from mdev device framework.
 155  * - 'force_remove' is set to 'false' when called from sysfs's 'remove' which
 156  *   indicates that if the mdev device is active, used by VMM or userspace
 157  *   application, vendor driver could return error then don't remove the device.
 158  * - 'force_remove' is set to 'true' when called from mdev_unregister_device()
 159  *   which indicate that parent device is being removed from mdev device
 160  *   framework so remove mdev device forcefully.
 161  */
 162 static int mdev_device_remove_ops(struct mdev_device *mdev, bool force_remove)
 163 {
 164         struct mdev_parent *parent = mdev->parent;
 165         int ret;
 166
 167         /*
 168          * Vendor driver can return error if VMM or userspace application is
 169          * using this mdev device.
 170          */
 171         ret = parent->ops->remove(mdev);
 172         if (ret && !force_remove)
 173                 return -EBUSY;
 174
 175         sysfs_remove_groups(&mdev->dev.kobj, parent->ops->mdev_attr_groups);
 176         return 0;
 177 }
 178
 179 static int mdev_device_remove_cb(struct device *dev, void *data)
 180 {
 181         if (!dev_is_mdev(dev))
 182                 return 0;
 183
 184         return mdev_device_remove(dev, data ? *(bool *)data : true);
 185 }
 186
 187 /*
 188  * mdev_register_device : Register a device
 189  * @dev: device structure representing parent device.
 190  * @ops: Parent device operation structure to be registered.
 191  *
 192  * Add device to list of registered parent devices.
 193  * Returns a negative value on error, otherwise 0.
 194  */
 195 int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops)
 196 {
 197         int ret;
 198         struct mdev_parent *parent;
 199
 200         /* check for mandatory ops */
 201         if (!ops || !ops->create || !ops->remove || !ops->supported_type_groups)
 202                 return -EINVAL;
 203
 204         dev = get_device(dev);
 205         if (!dev)
 206                 return -EINVAL;
 207
 208         mutex_lock(&parent_list_lock);
 209
 210         /* Check for duplicate */
 211         parent = __find_parent_device(dev);
 212         if (parent) {
 213                 ret = -EEXIST;
 214                 goto add_dev_err;
 215         }
 216
 217         parent = kzalloc(sizeof(*parent), GFP_KERNEL);
 218         if (!parent) {
 219                 ret = -ENOMEM;
 220                 goto add_dev_err;
 221         }
 222
 223         kref_init(&parent->ref);
 224         mutex_init(&parent->lock);
 225
 226         parent->dev = dev;
 227         parent->ops = ops;
 228
 229         if (!mdev_bus_compat_class) {
 230                 mdev_bus_compat_class = class_compat_register("mdev_bus");
 231                 if (!mdev_bus_compat_class) {
 232                         ret = -ENOMEM;
 233                         goto add_dev_err;
 234                 }
 235         }
 236
 237         ret = parent_create_sysfs_files(parent);
 238         if (ret)
 239                 goto add_dev_err;
 240
 241         ret = class_compat_create_link(mdev_bus_compat_class, dev, NULL);
 242         if (ret)
 243                 dev_warn(dev, "Failed to create compatibility class link\n");
 244
 245         list_add(&parent->next, &parent_list);
 246         mutex_unlock(&parent_list_lock);
 247
 248         dev_info(dev, "MDEV: Registered\n");
 249         return 0;
 250
 251 add_dev_err:
 252         mutex_unlock(&parent_list_lock);
 253         if (parent)
 254                 mdev_put_parent(parent);
 255         else
 256                 put_device(dev);
 257         return ret;
 258 }
 259 EXPORT_SYMBOL(mdev_register_device);
 260
 261 /*
 262  * mdev_unregister_device : Unregister a parent device
 263  * @dev: device structure representing parent device.
 264  *
 265  * Remove device from list of registered parent devices. Give a chance to free
 266  * existing mediated devices for given device.
 267  */
 268
 269 void mdev_unregister_device(struct device *dev)
 270 {
 271         struct mdev_parent *parent;
 272         bool force_remove = true;
 273
 274         mutex_lock(&parent_list_lock);
 275         parent = __find_parent_device(dev);
 276
 277         if (!parent) {
 278                 mutex_unlock(&parent_list_lock);
 279                 return;
 280         }
 281         dev_info(dev, "MDEV: Unregistering\n");
 282
 283         list_del(&parent->next);
 284         class_compat_remove_link(mdev_bus_compat_class, dev, NULL);
 285
 286         device_for_each_child(dev, (void *)&force_remove,
 287                               mdev_device_remove_cb);
 288
 289         parent_remove_sysfs_files(parent);
 290
 291         mutex_unlock(&parent_list_lock);
 292         mdev_put_parent(parent);
 293 }
 294 EXPORT_SYMBOL(mdev_unregister_device);
 295
 296 static void mdev_device_release(struct device *dev)
 297 {
 298         struct mdev_device *mdev = to_mdev_device(dev);
 299
 300         dev_dbg(&mdev->dev, "MDEV: destroying\n");
 301         kfree(mdev);
 302 }
 303
 304 int mdev_device_create(struct kobject *kobj, struct device *dev, uuid_le uuid)
 305 {
 306         int ret;
 307         struct mdev_device *mdev;
 308         struct mdev_parent *parent;
 309         struct mdev_type *type = to_mdev_type(kobj);
 310
 311         parent = mdev_get_parent(type->parent);
 312         if (!parent)
 313                 return -EINVAL;
 314
 315         mutex_lock(&parent->lock);
 316
 317         /* Check for duplicate */
 318         if (mdev_device_exist(parent, uuid)) {
 319                 ret = -EEXIST;
 320                 goto create_err;
 321         }
 322
 323         mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
 324         if (!mdev) {
 325                 ret = -ENOMEM;
 326                 goto create_err;
 327         }
 328
 329         memcpy(&mdev->uuid, &uuid, sizeof(uuid_le));
 330         mdev->parent = parent;
 331         kref_init(&mdev->ref);
 332
 333         mdev->dev.parent  = dev;
 334         mdev->dev.bus     = &mdev_bus_type;
 335         mdev->dev.release = mdev_device_release;
 336         dev_set_name(&mdev->dev, "%pUl", uuid.b);
 337
 338         ret = device_register(&mdev->dev);
 339         if (ret) {
 340                 put_device(&mdev->dev);
 341                 goto create_err;
 342         }
 343
 344         ret = mdev_device_create_ops(kobj, mdev);
 345         if (ret)
 346                 goto create_failed;
 347
 348         ret = mdev_create_sysfs_files(&mdev->dev, type);
 349         if (ret) {
 350                 mdev_device_remove_ops(mdev, true);
 351                 goto create_failed;
 352         }
 353
 354         mdev->type_kobj = kobj;
 355         dev_dbg(&mdev->dev, "MDEV: created\n");
 356
 357         mutex_unlock(&parent->lock);
 358
 359         mutex_lock(&mdev_list_lock);
 360         list_add(&mdev->next, &mdev_list);
 361         mutex_unlock(&mdev_list_lock);
 362
 363         return ret;
 364
 365 create_failed:
 366         device_unregister(&mdev->dev);
 367
 368 create_err:
 369         mutex_unlock(&parent->lock);
 370         mdev_put_parent(parent);
 371         return ret;
 372 }
 373
 374 int mdev_device_remove(struct device *dev, bool force_remove)
 375 {
 376         struct mdev_device *mdev, *tmp;
 377         struct mdev_parent *parent;
 378         struct mdev_type *type;
 379         int ret;
 380         bool found = false;
 381
 382         mdev = to_mdev_device(dev);
 383
 384         mutex_lock(&mdev_list_lock);
 385         list_for_each_entry(tmp, &mdev_list, next) {
 386                 if (tmp == mdev) {
 387                         found = true;
 388                         break;
 389                 }
 390         }
 391
 392         if (found)
 393                 list_del(&mdev->next);
 394
 395         mutex_unlock(&mdev_list_lock);
 396
 397         if (!found)
 398                 return -ENODEV;
 399
 400         type = to_mdev_type(mdev->type_kobj);
 401         parent = mdev->parent;
 402         mutex_lock(&parent->lock);
 403
 404         ret = mdev_device_remove_ops(mdev, force_remove);
 405         if (ret) {
 406                 mutex_unlock(&parent->lock);
 407
 408                 mutex_lock(&mdev_list_lock);
 409                 list_add(&mdev->next, &mdev_list);
 410                 mutex_unlock(&mdev_list_lock);
 411
 412                 return ret;
 413         }
 414
 415         mdev_remove_sysfs_files(dev, type);
 416         device_unregister(dev);
 417         mutex_unlock(&parent->lock);
 418         mdev_put_parent(parent);
 419
 420         return 0;
 421 }
 422
 423 static int __init mdev_init(void)
 424 {
 425         int ret;
 426
 427         ret = mdev_bus_register();
 428
 429         /*
 430          * Attempt to load known vfio_mdev.  This gives us a working environment
 431          * without the user needing to explicitly load vfio_mdev driver.
 432          */
 433         if (!ret)
 434                 request_module_nowait("vfio_mdev");
 435
 436         return ret;
 437 }
 438
 439 static void __exit mdev_exit(void)
 440 {
 441         if (mdev_bus_compat_class)
 442                 class_compat_unregister(mdev_bus_compat_class);
 443
 444         mdev_bus_unregister();
 445 }
 446
 447 module_init(mdev_init)
 448 module_exit(mdev_exit)
 449
 450 MODULE_VERSION(DRIVER_VERSION);
 451 MODULE_LICENSE("GPL v2");
 452 MODULE_AUTHOR(DRIVER_AUTHOR);
 453 MODULE_DESCRIPTION(DRIVER_DESC);