// SPDX-License-Identifier: GPL-2.0-only/* * Mediated device Core Driver * * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved. *     Author: Neo Jia <cjia@nvidia.com> *             Kirti Wankhede <kwankhede@nvidia.com> */ #include <linux/module.h>#include <linux/device.h>#include <linux/slab.h>#include <linux/uuid.h>#include <linux/sysfs.h>#include <linux/mdev.h> #include "mdev_private.h" #define DRIVER_VERSION		"0.1"#define DRIVER_AUTHOR		"NVIDIA Corporation"#define DRIVER_DESC		"Mediated device Core Driver" static LIST_HEAD(parent_list);static DEFINE_MUTEX(parent_list_lock);static struct class_compat *mdev_bus_compat_class; static LIST_HEAD(mdev_list);static DEFINE_MUTEX(mdev_list_lock); struct device *mdev_parent_dev(struct mdev_device *mdev){	return mdev->type->parent->dev;}EXPORT_SYMBOL(mdev_parent_dev); /* * Return the index in supported_type_groups that this mdev_device was created * from. */unsigned int mdev_get_type_group_id(struct mdev_device *mdev){	return mdev->type->type_group_id;}EXPORT_SYMBOL(mdev_get_type_group_id); /* * Used in mdev_type_attribute sysfs functions to return the index in the * supported_type_groups that the sysfs is called from. */unsigned int mtype_get_type_group_id(struct mdev_type *mtype){	return mtype->type_group_id;}EXPORT_SYMBOL(mtype_get_type_group_id); /* * Used in mdev_type_attribute sysfs functions to return the parent struct * device */struct device *mtype_get_parent_dev(struct mdev_type *mtype){	return mtype->parent->dev;}EXPORT_SYMBOL(mtype_get_parent_dev); /* Should be called holding parent_list_lock */static struct mdev_parent *__find_parent_device(struct device *dev){	struct mdev_parent *parent; 	list_for_each_entry(parent, &parent_list, next) {		if (parent->dev == dev)			return parent;	}	return NULL;} void mdev_release_parent(struct kref *kref){	struct mdev_parent *parent = container_of(kref, struct mdev_parent,						  ref);	struct device *dev = parent->dev; 	kfree(parent);	put_device(dev);} /* Caller must hold parent unreg_sem read or write lock */static void mdev_device_remove_common(struct mdev_device *mdev){	struct mdev_parent *parent = mdev->type->parent;	int ret; 	mdev_remove_sysfs_files(mdev);	device_del(&mdev->dev);	lockdep_assert_held(&parent->unreg_sem);	if (parent->ops->remove) {		ret = parent->ops->remove(mdev);		if (ret)			dev_err(&mdev->dev, "Remove failed: err=%d\n", ret);	} 	/* Balances with device_initialize() */	put_device(&mdev->dev);} static int mdev_device_remove_cb(struct device *dev, void *data){	struct mdev_device *mdev = mdev_from_dev(dev); 	if (mdev)		mdev_device_remove_common(mdev);	return 0;} /* * mdev_register_device : Register a device * @dev: device structure representing parent device. * @ops: Parent device operation structure to be registered. * * Add device to list of registered parent devices. * Returns a negative value on error, otherwise 0. */int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops){	int ret;	struct mdev_parent *parent;	char *env_string = "MDEV_STATE=registered";	char *envp[] = { env_string, NULL }; 	/* check for mandatory ops */	if (!ops || !ops->supported_type_groups)		return -EINVAL;	if (!ops->device_driver && (!ops->create || !ops->remove))		return -EINVAL; 	dev = get_device(dev);	if (!dev)		return -EINVAL; 	mutex_lock(&parent_list_lock); 	/* Check for duplicate */	parent = __find_parent_device(dev);	if (parent) {		parent = NULL;		ret = -EEXIST;		goto add_dev_err;	} 	parent = kzalloc(sizeof(*parent), GFP_KERNEL);	if (!parent) {		ret = -ENOMEM;		goto add_dev_err;	} 	kref_init(&parent->ref);	init_rwsem(&parent->unreg_sem); 	parent->dev = dev;	parent->ops = ops; 	if (!mdev_bus_compat_class) {		mdev_bus_compat_class = class_compat_register("mdev_bus");		if (!mdev_bus_compat_class) {			ret = -ENOMEM;			goto add_dev_err;		}	} 	ret = parent_create_sysfs_files(parent);	if (ret)		goto add_dev_err; 	ret = class_compat_create_link(mdev_bus_compat_class, dev, NULL);	if (ret)		dev_warn(dev, "Failed to create compatibility class link\n"); 	list_add(&parent->next, &parent_list);	mutex_unlock(&parent_list_lock); 	dev_info(dev, "MDEV: Registered\n");	kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp); 	return 0; add_dev_err:	mutex_unlock(&parent_list_lock);	if (parent)		mdev_put_parent(parent);	else		put_device(dev);	return ret;}EXPORT_SYMBOL(mdev_register_device); /* * mdev_unregister_device : Unregister a parent device * @dev: device structure representing parent device. * * Remove device from list of registered parent devices. Give a chance to free * existing mediated devices for given device. */ void mdev_unregister_device(struct device *dev){	struct mdev_parent *parent;	char *env_string = "MDEV_STATE=unregistered";	char *envp[] = { env_string, NULL }; 	mutex_lock(&parent_list_lock);	parent = __find_parent_device(dev); 	if (!parent) {		mutex_unlock(&parent_list_lock);		return;	}	dev_info(dev, "MDEV: Unregistering\n"); 	list_del(&parent->next);	mutex_unlock(&parent_list_lock); 	down_write(&parent->unreg_sem); 	class_compat_remove_link(mdev_bus_compat_class, dev, NULL); 	device_for_each_child(dev, NULL, mdev_device_remove_cb); 	parent_remove_sysfs_files(parent);	up_write(&parent->unreg_sem); 	mdev_put_parent(parent); 	/* We still have the caller's reference to use for the uevent */	kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp);}EXPORT_SYMBOL(mdev_unregister_device); static void mdev_device_release(struct device *dev){	struct mdev_device *mdev = to_mdev_device(dev); 	/* Pairs with the get in mdev_device_create() */	kobject_put(&mdev->type->kobj); 	mutex_lock(&mdev_list_lock);	list_del(&mdev->next);	mutex_unlock(&mdev_list_lock); 	dev_dbg(&mdev->dev, "MDEV: destroying\n");	kfree(mdev);} int mdev_device_create(struct mdev_type *type, const guid_t *uuid){	int ret;	struct mdev_device *mdev, *tmp;	struct mdev_parent *parent = type->parent;	struct mdev_driver *drv = parent->ops->device_driver; 	mutex_lock(&mdev_list_lock); 	/* Check for duplicate */	list_for_each_entry(tmp, &mdev_list, next) {		if (guid_equal(&tmp->uuid, uuid)) {			mutex_unlock(&mdev_list_lock);			return -EEXIST;		}	} 	mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);	if (!mdev) {		mutex_unlock(&mdev_list_lock);		return -ENOMEM;	} 	device_initialize(&mdev->dev);	mdev->dev.parent  = parent->dev;	mdev->dev.bus = &mdev_bus_type;	mdev->dev.release = mdev_device_release;	mdev->dev.groups = parent->ops->mdev_attr_groups;	mdev->type = type;	/* Pairs with the put in mdev_device_release() */	kobject_get(&type->kobj); 	guid_copy(&mdev->uuid, uuid);	list_add(&mdev->next, &mdev_list);	mutex_unlock(&mdev_list_lock); 	ret = dev_set_name(&mdev->dev, "%pUl", uuid);	if (ret)		goto out_put_device; 	/* Check if parent unregistration has started */	if (!down_read_trylock(&parent->unreg_sem)) {		ret = -ENODEV;		goto out_put_device;	} 	if (parent->ops->create) {		ret = parent->ops->create(mdev);		if (ret)			goto out_unlock;	} 	ret = device_add(&mdev->dev);	if (ret)		goto out_remove; 	if (!drv)		drv = &vfio_mdev_driver;	ret = device_driver_attach(&drv->driver, &mdev->dev);	if (ret)		goto out_del; 	ret = mdev_create_sysfs_files(mdev);	if (ret)		goto out_del; 	mdev->active = true;	dev_dbg(&mdev->dev, "MDEV: created\n");	up_read(&parent->unreg_sem); 	return 0; out_del:	device_del(&mdev->dev);out_remove:	if (parent->ops->remove)		parent->ops->remove(mdev);out_unlock:	up_read(&parent->unreg_sem);out_put_device:	put_device(&mdev->dev);	return ret;} int mdev_device_remove(struct mdev_device *mdev){	struct mdev_device *tmp;	struct mdev_parent *parent = mdev->type->parent; 	mutex_lock(&mdev_list_lock);	list_for_each_entry(tmp, &mdev_list, next) {		if (tmp == mdev)			break;	} 	if (tmp != mdev) {		mutex_unlock(&mdev_list_lock);		return -ENODEV;	} 	if (!mdev->active) {		mutex_unlock(&mdev_list_lock);		return -EAGAIN;	} 	mdev->active = false;	mutex_unlock(&mdev_list_lock); 	/* Check if parent unregistration has started */	if (!down_read_trylock(&parent->unreg_sem))		return -ENODEV; 	mdev_device_remove_common(mdev);	up_read(&parent->unreg_sem);	return 0;} static int __init mdev_init(void){	int rc; 	rc = mdev_bus_register();	if (rc)		return rc;	rc = mdev_register_driver(&vfio_mdev_driver);	if (rc)		goto err_bus;	return 0;err_bus:	mdev_bus_unregister();	return rc;} static void __exit mdev_exit(void){	mdev_unregister_driver(&vfio_mdev_driver); 	if (mdev_bus_compat_class)		class_compat_unregister(mdev_bus_compat_class); 	mdev_bus_unregister();} subsys_initcall(mdev_init)module_exit(mdev_exit) MODULE_VERSION(DRIVER_VERSION);MODULE_LICENSE("GPL v2");MODULE_AUTHOR(DRIVER_AUTHOR);MODULE_DESCRIPTION(DRIVER_DESC);