diff options
Diffstat (limited to 'drivers/vfio/vfio.c')
| -rw-r--r-- | drivers/vfio/vfio.c | 1415 |
1 files changed, 1415 insertions, 0 deletions
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c new file mode 100644 index 000000000000..17830c9c7cc6 --- /dev/null +++ b/drivers/vfio/vfio.c @@ -0,0 +1,1415 @@ +/* + * VFIO core + * + * Copyright (C) 2012 Red Hat, Inc. All rights reserved. + * Author: Alex Williamson <alex.williamson@redhat.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * Derived from original vfio: + * Copyright 2010 Cisco Systems, Inc. All rights reserved. + * Author: Tom Lyon, pugs@cisco.com + */ + +#include <linux/cdev.h> +#include <linux/compat.h> +#include <linux/device.h> +#include <linux/file.h> +#include <linux/anon_inodes.h> +#include <linux/fs.h> +#include <linux/idr.h> +#include <linux/iommu.h> +#include <linux/list.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/sched.h> +#include <linux/slab.h> +#include <linux/string.h> +#include <linux/uaccess.h> +#include <linux/vfio.h> +#include <linux/wait.h> + +#define DRIVER_VERSION "0.3" +#define DRIVER_AUTHOR "Alex Williamson <alex.williamson@redhat.com>" +#define DRIVER_DESC "VFIO - User Level meta-driver" + +static struct vfio { + struct class *class; + struct list_head iommu_drivers_list; + struct mutex iommu_drivers_lock; + struct list_head group_list; + struct idr group_idr; + struct mutex group_lock; + struct cdev group_cdev; + struct device *dev; + dev_t devt; + struct cdev cdev; + wait_queue_head_t release_q; +} vfio; + +struct vfio_iommu_driver { + const struct vfio_iommu_driver_ops *ops; + struct list_head vfio_next; +}; + +struct vfio_container { + struct kref kref; + struct list_head group_list; + struct mutex group_lock; + struct vfio_iommu_driver *iommu_driver; + void *iommu_data; +}; + +struct vfio_group { + struct kref kref; + int minor; + atomic_t container_users; + struct iommu_group *iommu_group; + struct vfio_container *container; + struct list_head device_list; + struct mutex device_lock; + struct device *dev; + struct notifier_block nb; + struct list_head vfio_next; + struct list_head container_next; +}; + +struct vfio_device { + struct kref kref; + struct device *dev; + const struct vfio_device_ops *ops; + struct vfio_group *group; + struct list_head group_next; + void *device_data; +}; + +/** + * IOMMU driver registration + */ +int vfio_register_iommu_driver(const struct vfio_iommu_driver_ops *ops) +{ + struct vfio_iommu_driver *driver, *tmp; + + driver = kzalloc(sizeof(*driver), GFP_KERNEL); + if (!driver) + return -ENOMEM; + + driver->ops = ops; + + mutex_lock(&vfio.iommu_drivers_lock); + + /* Check for duplicates */ + list_for_each_entry(tmp, &vfio.iommu_drivers_list, vfio_next) { + if (tmp->ops == ops) { + mutex_unlock(&vfio.iommu_drivers_lock); + kfree(driver); + return -EINVAL; + } + } + + list_add(&driver->vfio_next, &vfio.iommu_drivers_list); + + mutex_unlock(&vfio.iommu_drivers_lock); + + return 0; +} +EXPORT_SYMBOL_GPL(vfio_register_iommu_driver); + +void vfio_unregister_iommu_driver(const struct vfio_iommu_driver_ops *ops) +{ + struct vfio_iommu_driver *driver; + + mutex_lock(&vfio.iommu_drivers_lock); + list_for_each_entry(driver, &vfio.iommu_drivers_list, vfio_next) { + if (driver->ops == ops) { + list_del(&driver->vfio_next); + mutex_unlock(&vfio.iommu_drivers_lock); + kfree(driver); + return; + } + } + mutex_unlock(&vfio.iommu_drivers_lock); +} +EXPORT_SYMBOL_GPL(vfio_unregister_iommu_driver); + +/** + * Group minor allocation/free - both called with vfio.group_lock held + */ +static int vfio_alloc_group_minor(struct vfio_group *group) +{ + int ret, minor; + +again: + if (unlikely(idr_pre_get(&vfio.group_idr, GFP_KERNEL) == 0)) + return -ENOMEM; + + /* index 0 is used by /dev/vfio/vfio */ + ret = idr_get_new_above(&vfio.group_idr, group, 1, &minor); + if (ret == -EAGAIN) + goto again; + if (ret || minor > MINORMASK) { + if (minor > MINORMASK) + idr_remove(&vfio.group_idr, minor); + return -ENOSPC; + } + + return minor; +} + +static void vfio_free_group_minor(int minor) +{ + idr_remove(&vfio.group_idr, minor); +} + +static int vfio_iommu_group_notifier(struct notifier_block *nb, + unsigned long action, void *data); +static void vfio_group_get(struct vfio_group *group); + +/** + * Container objects - containers are created when /dev/vfio/vfio is + * opened, but their lifecycle extends until the last user is done, so + * it's freed via kref. Must support container/group/device being + * closed in any order. + */ +static void vfio_container_get(struct vfio_container *container) +{ + kref_get(&container->kref); +} + +static void vfio_container_release(struct kref *kref) +{ + struct vfio_container *container; + container = container_of(kref, struct vfio_container, kref); + + kfree(container); +} + +static void vfio_container_put(struct vfio_container *container) +{ + kref_put(&container->kref, vfio_container_release); +} + +/** + * Group objects - create, release, get, put, search + */ +static struct vfio_group *vfio_create_group(struct iommu_group *iommu_group) +{ + struct vfio_group *group, *tmp; + struct device *dev; + int ret, minor; + + group = kzalloc(sizeof(*group), GFP_KERNEL); + if (!group) + return ERR_PTR(-ENOMEM); + + kref_init(&group->kref); + INIT_LIST_HEAD(&group->device_list); + mutex_init(&group->device_lock); + atomic_set(&group->container_users, 0); + group->iommu_group = iommu_group; + + group->nb.notifier_call = vfio_iommu_group_notifier; + + /* + * blocking notifiers acquire a rwsem around registering and hold + * it around callback. Therefore, need to register outside of + * vfio.group_lock to avoid A-B/B-A contention. Our callback won't + * do anything unless it can find the group in vfio.group_list, so + * no harm in registering early. + */ + ret = iommu_group_register_notifier(iommu_group, &group->nb); + if (ret) { + kfree(group); + return ERR_PTR(ret); + } + + mutex_lock(&vfio.group_lock); + + minor = vfio_alloc_group_minor(group); + if (minor < 0) { + mutex_unlock(&vfio.group_lock); + kfree(group); + return ERR_PTR(minor); + } + + /* Did we race creating this group? */ + list_for_each_entry(tmp, &vfio.group_list, vfio_next) { + if (tmp->iommu_group == iommu_group) { + vfio_group_get(tmp); + vfio_free_group_minor(minor); + mutex_unlock(&vfio.group_lock); + kfree(group); + return tmp; + } + } + + dev = device_create(vfio.class, NULL, MKDEV(MAJOR(vfio.devt), minor), + group, "%d", iommu_group_id(iommu_group)); + if (IS_ERR(dev)) { + vfio_free_group_minor(minor); + mutex_unlock(&vfio.group_lock); + kfree(group); + return (struct vfio_group *)dev; /* ERR_PTR */ + } + + group->minor = minor; + group->dev = dev; + + list_add(&group->vfio_next, &vfio.group_list); + + mutex_unlock(&vfio.group_lock); + + return group; +} + +/* called with vfio.group_lock held */ +static void vfio_group_release(struct kref *kref) +{ + struct vfio_group *group = container_of(kref, struct vfio_group, kref); + + WARN_ON(!list_empty(&group->device_list)); + + device_destroy(vfio.class, MKDEV(MAJOR(vfio.devt), group->minor)); + list_del(&group->vfio_next); + vfio_free_group_minor(group->minor); + + mutex_unlock(&vfio.group_lock); + + /* + * Unregister outside of lock. A spurious callback is harmless now + * that the group is no longer in vfio.group_list. + */ + iommu_group_unregister_notifier(group->iommu_group, &group->nb); + + kfree(group); +} + +static void vfio_group_put(struct vfio_group *group) +{ + kref_put_mutex(&group->kref, vfio_group_release, &vfio.group_lock); +} + +/* Assume group_lock or group reference is held */ +static void vfio_group_get(struct vfio_group *group) +{ + kref_get(&group->kref); +} + +/* + * Not really a try as we will sleep for mutex, but we need to make + * sure the group pointer is valid under lock and get a reference. + */ +static struct vfio_group *vfio_group_try_get(struct vfio_group *group) +{ + struct vfio_group *target = group; + + mutex_lock(&vfio.group_lock); + list_for_each_entry(group, &vfio.group_list, vfio_next) { + if (group == target) { + vfio_group_get(group); + mutex_unlock(&vfio.group_lock); + return group; + } + } + mutex_unlock(&vfio.group_lock); + + return NULL; +} + +static +struct vfio_group *vfio_group_get_from_iommu(struct iommu_group *iommu_group) +{ + struct vfio_group *group; + + mutex_lock(&vfio.group_lock); + list_for_each_entry(group, &vfio.group_list, vfio_next) { + if (group->iommu_group == iommu_group) { + vfio_group_get(group); + mutex_unlock(&vfio.group_lock); + return group; + } + } + mutex_unlock(&vfio.group_lock); + + return NULL; +} + +static struct vfio_group *vfio_group_get_from_minor(int minor) +{ + struct vfio_group *group; + + mutex_lock(&vfio.group_lock); + group = idr_find(&vfio.group_idr, minor); + if (!group) { + mutex_unlock(&vfio.group_lock); + return NULL; + } + vfio_group_get(group); + mutex_unlock(&vfio.group_lock); + + return group; +} + +/** + * Device objects - create, release, get, put, search + */ +static +struct vfio_device *vfio_group_create_device(struct vfio_group *group, + struct device *dev, + const struct vfio_device_ops *ops, + void *device_data) +{ + struct vfio_device *device; + int ret; + + device = kzalloc(sizeof(*device), GFP_KERNEL); + if (!device) + return ERR_PTR(-ENOMEM); + + kref_init(&device->kref); + device->dev = dev; + device->group = group; + device->ops = ops; + device->device_data = device_data; + + ret = dev_set_drvdata(dev, device); + if (ret) { + kfree(device); + return ERR_PTR(ret); + } + + /* No need to get group_lock, caller has group reference */ + vfio_group_get(group); + + mutex_lock(&group->device_lock); + list_add(&device->group_next, &group->device_list); + mutex_unlock(&group->device_lock); + + return device; +} + +static void vfio_device_release(struct kref *kref) +{ + struct vfio_device *device = container_of(kref, + struct vfio_device, kref); + struct vfio_group *group = device->group; + + list_del(&device->group_next); + mutex_unlock(&group->device_lock); + + dev_set_drvdata(device->dev, NULL); + + kfree(device); + + /* vfio_del_group_dev may be waiting for this device */ + wake_up(&vfio.release_q); +} + +/* Device reference always implies a group reference */ +static void vfio_device_put(struct vfio_device *device) +{ + struct vfio_group *group = device->group; + kref_put_mutex(&device->kref, vfio_device_release, &group->device_lock); + vfio_group_put(group); +} + +static void vfio_device_get(struct vfio_device *device) +{ + vfio_group_get(device->group); + kref_get(&device->kref); +} + +static struct vfio_device *vfio_group_get_device(struct vfio_group *group, + struct device *dev) +{ + struct vfio_device *device; + + mutex_lock(&group->device_lock); + list_for_each_entry(device, &group->device_list, group_next) { + if (device->dev == dev) { + vfio_device_get(device); + mutex_unlock(&group->device_lock); + return device; + } + } + mutex_unlock(&group->device_lock); + return NULL; +} + +/* + * Whitelist some drivers that we know are safe (no dma) or just sit on + * a device. It's not always practical to leave a device within a group + * driverless as it could get re-bound to something unsafe. + */ +static const char * const vfio_driver_whitelist[] = { "pci-stub" }; + +static bool vfio_whitelisted_driver(struct device_driver *drv) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(vfio_driver_whitelist); i++) { + if (!strcmp(drv->name, vfio_driver_whitelist[i])) + return true; + } + + return false; +} + +/* + * A vfio group is viable for use by userspace if all devices are either + * driver-less or bound to a vfio or whitelisted driver. We test the + * latter by the existence of a struct vfio_device matching the dev. + */ +static int vfio_dev_viable(struct device *dev, void *data) +{ + struct vfio_group *group = data; + struct vfio_device *device; + + if (!dev->driver || vfio_whitelisted_driver(dev->driver)) + return 0; + + device = vfio_group_get_device(group, dev); + if (device) { + vfio_device_put(device); + return 0; + } + + return -EINVAL; +} + +/** + * Async device support + */ +static int vfio_group_nb_add_dev(struct vfio_group *group, struct device *dev) +{ + struct vfio_device *device; + + /* Do we already know about it? We shouldn't */ + device = vfio_group_get_device(group, dev); + if (WARN_ON_ONCE(device)) { + vfio_device_put(device); + return 0; + } + + /* Nothing to do for idle groups */ + if (!atomic_read(&group->container_users)) + return 0; + + /* TODO Prevent device auto probing */ + WARN("Device %s added to live group %d!\n", dev_name(dev), + iommu_group_id(group->iommu_group)); + + return 0; +} + +static int vfio_group_nb_del_dev(struct vfio_group *group, struct device *dev) +{ + struct vfio_device *device; + + /* + * Expect to fall out here. If a device was in use, it would + * have been bound to a vfio sub-driver, which would have blocked + * in .remove at vfio_del_group_dev. Sanity check that we no + * longer track the device, so it's safe to remove. + */ + device = vfio_group_get_device(group, dev); + if (likely(!device)) + return 0; + + WARN("Device %s removed from live group %d!\n", dev_name(dev), + iommu_group_id(group->iommu_group)); + + vfio_device_put(device); + return 0; +} + +static int vfio_group_nb_verify(struct vfio_group *group, struct device *dev) +{ + /* We don't care what happens when the group isn't in use */ + if (!atomic_read(&group->container_users)) + return 0; + + return vfio_dev_viable(dev, group); +} + +static int vfio_iommu_group_notifier(struct notifier_block *nb, + unsigned long action, void *data) +{ + struct vfio_group *group = container_of(nb, struct vfio_group, nb); + struct device *dev = data; + + /* + * Need to go through a group_lock lookup to get a reference or + * we risk racing a group being removed. Leave a WARN_ON for + * debuging, but if the group no longer exists, a spurious notify + * is harmless. + */ + group = vfio_group_try_get(group); + if (WARN_ON(!group)) + return NOTIFY_OK; + + switch (action) { + case IOMMU_GROUP_NOTIFY_ADD_DEVICE: + vfio_group_nb_add_dev(group, dev); + break; + case IOMMU_GROUP_NOTIFY_DEL_DEVICE: + vfio_group_nb_del_dev(group, dev); + break; + case IOMMU_GROUP_NOTIFY_BIND_DRIVER: + pr_debug("%s: Device %s, group %d binding to driver\n", + __func__, dev_name(dev), + iommu_group_id(group->iommu_group)); + break; + case IOMMU_GROUP_NOTIFY_BOUND_DRIVER: + pr_debug("%s: Device %s, group %d bound to driver %s\n", + __func__, dev_name(dev), + iommu_group_id(group->iommu_group), dev->driver->name); + BUG_ON(vfio_group_nb_verify(group, dev)); + break; + case IOMMU_GROUP_NOTIFY_UNBIND_DRIVER: + pr_debug("%s: Device %s, group %d unbinding from driver %s\n", + __func__, dev_name(dev), + iommu_group_id(group->iommu_group), dev->driver->name); + break; + case IOMMU_GROUP_NOTIFY_UNBOUND_DRIVER: + pr_debug("%s: Device %s, group %d unbound from driver\n", + __func__, dev_name(dev), + iommu_group_id(group->iommu_group)); + /* + * XXX An unbound device in a live group is ok, but we'd + * really like to avoid the above BUG_ON by preventing other + * drivers from binding to it. Once that occurs, we have to + * stop the system to maintain isolation. At a minimum, we'd + * want a toggle to disable driver auto probe for this device. + */ + break; + } + + vfio_group_put(group); + return NOTIFY_OK; +} + +/** + * VFIO driver API + */ +int vfio_add_group_dev(struct device *dev, + const struct vfio_device_ops *ops, void *device_data) +{ + struct iommu_group *iommu_group; + struct vfio_group *group; + struct vfio_device *device; + + iommu_group = iommu_group_get(dev); + if (!iommu_group) + return -EINVAL; + + group = vfio_group_get_from_iommu(iommu_group); + if (!group) { + group = vfio_create_group(iommu_group); + if (IS_ERR(group)) { + iommu_group_put(iommu_group); + return PTR_ERR(group); + } + } + + device = vfio_group_get_device(group, dev); + if (device) { + WARN(1, "Device %s already exists on group %d\n", + dev_name(dev), iommu_group_id(iommu_group)); + vfio_device_put(device); + vfio_group_put(group); + iommu_group_put(iommu_group); + return -EBUSY; + } + + device = vfio_group_create_device(group, dev, ops, device_data); + if (IS_ERR(device)) { + vfio_group_put(group); + iommu_group_put(iommu_group); + return PTR_ERR(device); + } + + /* + * Added device holds reference to iommu_group and vfio_device + * (which in turn holds reference to vfio_group). Drop extra + * group reference used while acquiring device. + */ + vfio_group_put(group); + + return 0; +} +EXPORT_SYMBOL_GPL(vfio_add_group_dev); + +/* Test whether a struct device is present in our tracking */ +static bool vfio_dev_present(struct device *dev) +{ + struct iommu_group *iommu_group; + struct vfio_group *group; + struct vfio_device *device; + + iommu_group = iommu_group_get(dev); + if (!iommu_group) + return false; + + group = vfio_group_get_from_iommu(iommu_group); + if (!group) { + iommu_group_put(iommu_group); + return false; + } + + device = vfio_group_get_device(group, dev); + if (!device) { + vfio_group_put(group); + iommu_group_put(iommu_group); + return false; + } + + vfio_device_put(device); + vfio_group_put(group); + iommu_group_put(iommu_group); + return true; +} + +/* + * Decrement the device reference count and wait for the device to be + * removed. Open file descriptors for the device... */ +void *vfio_del_group_dev(struct device *dev) +{ + struct vfio_device *device = dev_get_drvdata(dev); + struct vfio_group *group = device->group; + struct iommu_group *iommu_group = group->iommu_group; + void *device_data = device->device_data; + + vfio_device_put(device); + + /* TODO send a signal to encourage this to be released */ + wait_event(vfio.release_q, !vfio_dev_present(dev)); + + iommu_group_put(iommu_group); + + return device_data; +} +EXPORT_SYMBOL_GPL(vfio_del_group_dev); + +/** + * VFIO base fd, /dev/vfio/vfio + */ +static long vfio_ioctl_check_extension(struct vfio_container *container, + unsigned long arg) +{ + struct vfio_iommu_driver *driver = container->iommu_driver; + long ret = 0; + + switch (arg) { + /* No base extensions yet */ + default: + /* + * If no driver is set, poll all registered drivers for + * extensions and return the first positive result. If + * a driver is already set, further queries will be passed + * only to that driver. + */ + if (!driver) { + mutex_lock(&vfio.iommu_drivers_lock); + list_for_each_entry(driver, &vfio.iommu_drivers_list, + vfio_next) { + if (!try_module_get(driver->ops->owner)) + continue; + + ret = driver->ops->ioctl(NULL, + VFIO_CHECK_EXTENSION, + arg); + module_put(driver->ops->owner); + if (ret > 0) + break; + } + mutex_unlock(&vfio.iommu_drivers_lock); + } else + ret = driver->ops->ioctl(container->iommu_data, + VFIO_CHECK_EXTENSION, arg); + } + + return ret; +} + +/* hold container->group_lock */ +static int __vfio_container_attach_groups(struct vfio_container *container, + struct vfio_iommu_driver *driver, + void *data) +{ + struct vfio_group *group; + int ret = -ENODEV; + + list_for_each_entry(group, &container->group_list, container_next) { + ret = driver->ops->attach_group(data, group->iommu_group); + if (ret) + goto unwind; + } + + return ret; + +unwind: + list_for_each_entry_continue_reverse(group, &container->group_list, + container_next) { + driver->ops->detach_group(data, group->iommu_group); + } + + return ret; +} + +static long vfio_ioctl_set_iommu(struct vfio_container *container, + unsigned long arg) +{ + struct vfio_iommu_driver *driver; + long ret = -ENODEV; + + mutex_lock(&container->group_lock); + + /* + * The container is designed to be an unprivileged interface while + * the group can be assigned to specific users. Therefore, only by + * adding a group to a container does the user get the privilege of + * enabling the iommu, which may allocate finite resources. There + * is no unset_iommu, but by removing all the groups from a container, + * the container is deprivileged and returns to an unset state. + */ + if (list_empty(&container->group_list) || container->iommu_driver) { + mutex_unlock(&container->group_lock); + return -EINVAL; + } + + mutex_lock(&vfio.iommu_drivers_lock); + list_for_each_entry(driver, &vfio.iommu_drivers_list, vfio_next) { + void *data; + + if (!try_module_get(driver->ops->owner)) + continue; + + /* + * The arg magic for SET_IOMMU is the same as CHECK_EXTENSION, + * so test which iommu driver reported support for this + * extension and call open on them. We also pass them the + * magic, allowing a single driver to support multiple + * interfaces if they'd like. + */ + if (driver->ops->ioctl(NULL, VFIO_CHECK_EXTENSION, arg) <= 0) { + module_put(driver->ops->owner); + continue; + } + + /* module reference holds the driver we're working on */ + mutex_unlock(&vfio.iommu_drivers_lock); + + data = driver->ops->open(arg); + if (IS_ERR(data)) { + ret = PTR_ERR(data); + module_put(driver->ops->owner); + goto skip_drivers_unlock; + } + + ret = __vfio_container_attach_groups(container, driver, data); + if (!ret) { + container->iommu_driver = driver; + container->iommu_data = data; + } else { + driver->ops->release(data); + module_put(driver->ops->owner); + } + + goto skip_drivers_unlock; + } + + mutex_unlock(&vfio.iommu_drivers_lock); +skip_drivers_unlock: + mutex_unlock(&container->group_lock); + + return ret; +} + +static long vfio_fops_unl_ioctl(struct file *filep, + unsigned int cmd, unsigned long arg) +{ + struct vfio_container *container = filep->private_data; + struct vfio_iommu_driver *driver; + void *data; + long ret = -EINVAL; + + if (!container) + return ret; + + driver = container->iommu_driver; + data = container->iommu_data; + + switch (cmd) { + case VFIO_GET_API_VERSION: + ret = VFIO_API_VERSION; + break; + case VFIO_CHECK_EXTENSION: + ret = vfio_ioctl_check_extension(container, arg); + break; + case VFIO_SET_IOMMU: + ret = vfio_ioctl_set_iommu(container, arg); + break; + default: + if (driver) /* passthrough all unrecognized ioctls */ + ret = driver->ops->ioctl(data, cmd, arg); + } + + return ret; +} + +#ifdef CONFIG_COMPAT +static long vfio_fops_compat_ioctl(struct file *filep, + unsigned int cmd, unsigned long arg) +{ + arg = (unsigned long)compat_ptr(arg); + return vfio_fops_unl_ioctl(filep, cmd, arg); +} +#endif /* CONFIG_COMPAT */ + +static int vfio_fops_open(struct inode *inode, struct file *filep) +{ + struct vfio_container *container; + + container = kzalloc(sizeof(*container), GFP_KERNEL); + if (!container) + return -ENOMEM; + + INIT_LIST_HEAD(&container->group_list); + mutex_init(&container->group_lock); + kref_init(&container->kref); + + filep->private_data = container; + + return 0; +} + +static int vfio_fops_release(struct inode *inode, struct file *filep) +{ + struct vfio_container *container = filep->private_data; + + filep->private_data = NULL; + + vfio_container_put(container); + + return 0; +} + +/* + * Once an iommu driver is set, we optionally pass read/write/mmap + * on to the driver, allowing management interfaces beyond ioctl. + */ +static ssize_t vfio_fops_read(struct file *filep, char __user *buf, + size_t count, loff_t *ppos) +{ + struct vfio_container *container = filep->private_data; + struct vfio_iommu_driver *driver = container->iommu_driver; + + if (unlikely(!driver || !driver->ops->read)) + return -EINVAL; + + return driver->ops->read(container->iommu_data, buf, count, ppos); +} + +static ssize_t vfio_fops_write(struct file *filep, const char __user *buf, + size_t count, loff_t *ppos) +{ + struct vfio_container *container = filep->private_data; + struct vfio_iommu_driver *driver = container->iommu_driver; + + if (unlikely(!driver || !driver->ops->write)) + return -EINVAL; + + return driver->ops->write(container->iommu_data, buf, count, ppos); +} + +static int vfio_fops_mmap(struct file *filep, struct vm_area_struct *vma) +{ + struct vfio_container *container = filep->private_data; + struct vfio_iommu_driver *driver = container->iommu_driver; + + if (unlikely(!driver || !driver->ops->mmap)) + return -EINVAL; + + return driver->ops->mmap(container->iommu_data, vma); +} + +static const struct file_operations vfio_fops = { + .owner = THIS_MODULE, + .open = vfio_fops_open, + .release = vfio_fops_release, + .read = vfio_fops_read, + .write = vfio_fops_write, + .unlocked_ioctl = vfio_fops_unl_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = vfio_fops_compat_ioctl, +#endif + .mmap = vfio_fops_mmap, +}; + +/** + * VFIO Group fd, /dev/vfio/$GROUP + */ +static void __vfio_group_unset_container(struct vfio_group *group) +{ + struct vfio_container *container = group->container; + struct vfio_iommu_driver *driver; + + mutex_lock(&container->group_lock); + + driver = container->iommu_driver; + if (driver) + driver->ops->detach_group(container->iommu_data, + group->iommu_group); + + group->container = NULL; + list_del(&group->container_next); + + /* Detaching the last group deprivileges a container, remove iommu */ + if (driver && list_empty(&container->group_list)) { + driver->ops->release(container->iommu_data); + module_put(driver->ops->owner); + container->iommu_driver = NULL; + container->iommu_data = NULL; + } + + mutex_unlock(&container->group_lock); + + vfio_container_put(container); +} + +/* + * VFIO_GROUP_UNSET_CONTAINER should fail if there are other users or + * if there was no container to unset. Since the ioctl is called on + * the group, we know that still exists, therefore the only valid + * transition here is 1->0. + */ +static int vfio_group_unset_container(struct vfio_group *group) +{ + int users = atomic_cmpxchg(&group->container_users, 1, 0); + + if (!users) + return -EINVAL; + if (users != 1) + return -EBUSY; + + __vfio_group_unset_container(group); + + return 0; +} + +/* + * When removing container users, anything that removes the last user + * implicitly removes the group from the container. That is, if the + * group file descriptor is closed, as well as any device file descriptors, + * the group is free. + */ +static void vfio_group_try_dissolve_container(struct vfio_group *group) +{ + if (0 == atomic_dec_if_positive(&group->container_users)) + __vfio_group_unset_container(group); +} + +static int vfio_group_set_container(struct vfio_group *group, int container_fd) +{ + struct file *filep; + struct vfio_container *container; + struct vfio_iommu_driver *driver; + int ret = 0; + + if (atomic_read(&group->container_users)) + return -EINVAL; + + filep = fget(container_fd); + if (!filep) + return -EBADF; + + /* Sanity check, is this really our fd? */ + if (filep->f_op != &vfio_fops) { + fput(filep); + return -EINVAL; + } + + container = filep->private_data; + WARN_ON(!container); /* fget ensures we don't race vfio_release */ + + mutex_lock(&container->group_lock); + + driver = container->iommu_driver; + if (driver) { + ret = driver->ops->attach_group(container->iommu_data, + group->iommu_group); + if (ret) + goto unlock_out; + } + + group->container = container; + list_add(&group->container_next, &container->group_list); + + /* Get a reference on the container and mark a user within the group */ + vfio_container_get(container); + atomic_inc(&group->container_users); + +unlock_out: + mutex_unlock(&container->group_lock); + fput(filep); + + return ret; +} + +static bool vfio_group_viable(struct vfio_group *group) +{ + return (iommu_group_for_each_dev(group->iommu_group, + group, vfio_dev_viable) == 0); +} + +static const struct file_operations vfio_device_fops; + +static int vfio_group_get_device_fd(struct vfio_group *group, char *buf) +{ + struct vfio_device *device; + struct file *filep; + int ret = -ENODEV; + + if (0 == atomic_read(&group->container_users) || + !group->container->iommu_driver || !vfio_group_viable(group)) + return -EINVAL; + + mutex_lock(&group->device_lock); + list_for_each_entry(device, &group->device_list, group_next) { + if (strcmp(dev_name(device->dev), buf)) + continue; + + ret = device->ops->open(device->device_data); + if (ret) + break; + /* + * We can't use anon_inode_getfd() because we need to modify + * the f_mode flags directly to allow more than just ioctls + */ + ret = get_unused_fd(); + if (ret < 0) { + device->ops->release(device->device_data); + break; + } + + filep = anon_inode_getfile("[vfio-device]", &vfio_device_fops, + device, O_RDWR); + if (IS_ERR(filep)) { + put_unused_fd(ret); + ret = PTR_ERR(filep); + device->ops->release(device->device_data); + break; + } + + /* + * TODO: add an anon_inode interface to do this. + * Appears to be missing by lack of need rather than + * explicitly prevented. Now there's need. + */ + filep->f_mode |= (FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE); + + vfio_device_get(device); + atomic_inc(&group->container_users); + + fd_install(ret, filep); + break; + } + mutex_unlock(&group->device_lock); + + return ret; +} + +static long vfio_group_fops_unl_ioctl(struct file *filep, + unsigned int cmd, unsigned long arg) +{ + struct vfio_group *group = filep->private_data; + long ret = -ENOTTY; + + switch (cmd) { + case VFIO_GROUP_GET_STATUS: + { + struct vfio_group_status status; + unsigned long minsz; + + minsz = offsetofend(struct vfio_group_status, flags); + + if (copy_from_user(&status, (void __user *)arg, minsz)) + return -EFAULT; + + if (status.argsz < minsz) + return -EINVAL; + + status.flags = 0; + + if (vfio_group_viable(group)) + status.flags |= VFIO_GROUP_FLAGS_VIABLE; + + if (group->container) + status.flags |= VFIO_GROUP_FLAGS_CONTAINER_SET; + + if (copy_to_user((void __user *)arg, &status, minsz)) + return -EFAULT; + + ret = 0; + break; + } + case VFIO_GROUP_SET_CONTAINER: + { + int fd; + + if (get_user(fd, (int __user *)arg)) + return -EFAULT; + + if (fd < 0) + return -EINVAL; + + ret = vfio_group_set_container(group, fd); + break; + } + case VFIO_GROUP_UNSET_CONTAINER: + ret = vfio_group_unset_container(group); + break; + case VFIO_GROUP_GET_DEVICE_FD: + { + char *buf; + + buf = strndup_user((const char __user *)arg, PAGE_SIZE); + if (IS_ERR(buf)) + return PTR_ERR(buf); + + ret = vfio_group_get_device_fd(group, buf); + kfree(buf); + break; + } + } + + return ret; +} + +#ifdef CONFIG_COMPAT +static long vfio_group_fops_compat_ioctl(struct file *filep, + unsigned int cmd, unsigned long arg) +{ + arg = (unsigned long)compat_ptr(arg); + return vfio_group_fops_unl_ioctl(filep, cmd, arg); +} +#endif /* CONFIG_COMPAT */ + +static int vfio_group_fops_open(struct inode *inode, struct file *filep) +{ + struct vfio_group *group; + + group = vfio_group_get_from_minor(iminor(inode)); + if (!group) + return -ENODEV; + + if (group->container) { + vfio_group_put(group); + return -EBUSY; + } + + filep->private_data = group; + + return 0; +} + +static int vfio_group_fops_release(struct inode *inode, struct file *filep) +{ + struct vfio_group *group = filep->private_data; + + filep->private_data = NULL; + + vfio_group_try_dissolve_container(group); + + vfio_group_put(group); + + return 0; +} + +static const struct file_operations vfio_group_fops = { + .owner = THIS_MODULE, + .unlocked_ioctl = vfio_group_fops_unl_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = vfio_group_fops_compat_ioctl, +#endif + .open = vfio_group_fops_open, + .release = vfio_group_fops_release, +}; + +/** + * VFIO Device fd + */ +static int vfio_device_fops_release(struct inode *inode, struct file *filep) +{ + struct vfio_device *device = filep->private_data; + + device->ops->release(device->device_data); + + vfio_group_try_dissolve_container(device->group); + + vfio_device_put(device); + + return 0; +} + +static long vfio_device_fops_unl_ioctl(struct file *filep, + unsigned int cmd, unsigned long arg) +{ + struct vfio_device *device = filep->private_data; + + if (unlikely(!device->ops->ioctl)) + return -EINVAL; + + return device->ops->ioctl(device->device_data, cmd, arg); +} + +static ssize_t vfio_device_fops_read(struct file *filep, char __user *buf, + size_t count, loff_t *ppos) +{ + struct vfio_device *device = filep->private_data; + + if (unlikely(!device->ops->read)) + return -EINVAL; + + return device->ops->read(device->device_data, buf, count, ppos); +} + +static ssize_t vfio_device_fops_write(struct file *filep, + const char __user *buf, + size_t count, loff_t *ppos) +{ + struct vfio_device *device = filep->private_data; + + if (unlikely(!device->ops->write)) + return -EINVAL; + + return device->ops->write(device->device_data, buf, count, ppos); +} + +static int vfio_device_fops_mmap(struct file *filep, struct vm_area_struct *vma) +{ + struct vfio_device *device = filep->private_data; + + if (unlikely(!device->ops->mmap)) + return -EINVAL; + + return device->ops->mmap(device->device_data, vma); +} + +#ifdef CONFIG_COMPAT +static long vfio_device_fops_compat_ioctl(struct file *filep, + unsigned int cmd, unsigned long arg) +{ + arg = (unsigned long)compat_ptr(arg); + return vfio_device_fops_unl_ioctl(filep, cmd, arg); +} +#endif /* CONFIG_COMPAT */ + +static const struct file_operations vfio_device_fops = { + .owner = THIS_MODULE, + .release = vfio_device_fops_release, + .read = vfio_device_fops_read, + .write = vfio_device_fops_write, + .unlocked_ioctl = vfio_device_fops_unl_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = vfio_device_fops_compat_ioctl, +#endif + .mmap = vfio_device_fops_mmap, +}; + +/** + * Module/class support + */ +static char *vfio_devnode(struct device *dev, umode_t *mode) +{ + return kasprintf(GFP_KERNEL, "vfio/%s", dev_name(dev)); +} + +static int __init vfio_init(void) +{ + int ret; + + idr_init(&vfio.group_idr); + mutex_init(&vfio.group_lock); + mutex_init(&vfio.iommu_drivers_lock); + INIT_LIST_HEAD(&vfio.group_list); + INIT_LIST_HEAD(&vfio.iommu_drivers_list); + init_waitqueue_head(&vfio.release_q); + + vfio.class = class_create(THIS_MODULE, "vfio"); + if (IS_ERR(vfio.class)) { + ret = PTR_ERR(vfio.class); + goto err_class; + } + + vfio.class->devnode = vfio_devnode; + + ret = alloc_chrdev_region(&vfio.devt, 0, MINORMASK, "vfio"); + if (ret) + goto err_base_chrdev; + + cdev_init(&vfio.cdev, &vfio_fops); + ret = cdev_add(&vfio.cdev, vfio.devt, 1); + if (ret) + goto err_base_cdev; + + vfio.dev = device_create(vfio.class, NULL, vfio.devt, NULL, "vfio"); + if (IS_ERR(vfio.dev)) { + ret = PTR_ERR(vfio.dev); + goto err_base_dev; + } + + /* /dev/vfio/$GROUP */ + cdev_init(&vfio.group_cdev, &vfio_group_fops); + ret = cdev_add(&vfio.group_cdev, + MKDEV(MAJOR(vfio.devt), 1), MINORMASK - 1); + if (ret) + goto err_groups_cdev; + + pr_info(DRIVER_DESC " version: " DRIVER_VERSION "\n"); + + /* + * Attempt to load known iommu-drivers. This gives us a working + * environment without the user needing to explicitly load iommu + * drivers. + */ + request_module_nowait("vfio_iommu_type1"); + + return 0; + +err_groups_cdev: + device_destroy(vfio.class, vfio.devt); +err_base_dev: + cdev_del(&vfio.cdev); +err_base_cdev: + unregister_chrdev_region(vfio.devt, MINORMASK); +err_base_chrdev: + class_destroy(vfio.class); + vfio.class = NULL; +err_class: + return ret; +} + +static void __exit vfio_cleanup(void) +{ + WARN_ON(!list_empty(&vfio.group_list)); + + idr_destroy(&vfio.group_idr); + cdev_del(&vfio.group_cdev); + device_destroy(vfio.class, vfio.devt); + cdev_del(&vfio.cdev); + unregister_chrdev_region(vfio.devt, MINORMASK); + class_destroy(vfio.class); + vfio.class = NULL; +} + +module_init(vfio_init); +module_exit(vfio_cleanup); + +MODULE_VERSION(DRIVER_VERSION); +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR(DRIVER_AUTHOR); +MODULE_DESCRIPTION(DRIVER_DESC); |