// SPDX-License-Identifier: GPL-2.0-only
/*
 * VFIO core
 *
 * Copyright (C) 2012 Red Hat, Inc.  All rights reserved.
 *     Author: Alex Williamson <alex.williamson@redhat.com>
 *
 * Derived from original vfio:
 * Copyright 2010 Cisco Systems, Inc.  All rights reserved.
 * Author: Tom Lyon, pugs@cisco.com
 */

#include <linux/vfio.h>
#include <linux/iommufd.h>
#include <linux/anon_inodes.h>
#include "vfio.h"

static struct vfio {
        struct class                    *class;
        struct list_head                group_list;
        struct mutex                    group_lock; /* locks group_list */
        struct ida                      group_ida;
        dev_t                           group_devt;
} vfio;

static struct vfio_device *vfio_device_get_from_name(struct vfio_group *group,
                                                     char *buf)
{
        struct vfio_device *it, *device = ERR_PTR(-ENODEV);

        mutex_lock(&group->device_lock);
        list_for_each_entry(it, &group->device_list, group_next) {
                int ret;

                if (it->ops->match) {
                        ret = it->ops->match(it, buf);
                        if (ret < 0) {
                                device = ERR_PTR(ret);
                                break;
                        }
                } else {
                        ret = !strcmp(dev_name(it->dev), buf);
                }

                if (ret && vfio_device_try_get_registration(it)) {
                        device = it;
                        break;
                }
        }
        mutex_unlock(&group->device_lock);

        return device;
}

/*
 * VFIO Group fd, /dev/vfio/$GROUP
 */
static bool vfio_group_has_iommu(struct vfio_group *group)
{
        lockdep_assert_held(&group->group_lock);
        /*
         * There can only be users if there is a container, and if there is a
         * container there must be users.
         */
        WARN_ON(!group->container != !group->container_users);

        return group->container || group->iommufd;
}

/*
 * 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_ioctl_unset_container(struct vfio_group *group)
{
        int ret = 0;

        mutex_lock(&group->group_lock);
        if (!vfio_group_has_iommu(group)) {
                ret = -EINVAL;
                goto out_unlock;
        }
        if (group->container) {
                if (group->container_users != 1) {
                        ret = -EBUSY;
                        goto out_unlock;
                }
                vfio_group_detach_container(group);
        }
        if (group->iommufd) {
                iommufd_ctx_put(group->iommufd);
                group->iommufd = NULL;
        }

out_unlock:
        mutex_unlock(&group->group_lock);
        return ret;
}

static int vfio_group_ioctl_set_container(struct vfio_group *group,
                                          int __user *arg)
{
        struct vfio_container *container;
        struct iommufd_ctx *iommufd;
        int ret;
        int fd;

        if (get_user(fd, arg))
                return -EFAULT;

        CLASS(fd, f)(fd);
        if (fd_empty(f))
                return -EBADF;

        mutex_lock(&group->group_lock);
        if (vfio_group_has_iommu(group)) {
                ret = -EINVAL;
                goto out_unlock;
        }
        if (!group->iommu_group) {
                ret = -ENODEV;
                goto out_unlock;
        }

        container = vfio_container_from_file(fd_file(f));
        if (container) {
                ret = vfio_container_attach_group(container, group);
                goto out_unlock;
        }

        iommufd = iommufd_ctx_from_file(fd_file(f));
        if (!IS_ERR(iommufd)) {
                if (IS_ENABLED(CONFIG_VFIO_NOIOMMU) &&
                    group->type == VFIO_NO_IOMMU)
                        ret = iommufd_vfio_compat_set_no_iommu(iommufd);
                else
                        ret = iommufd_vfio_compat_ioas_create(iommufd);

                if (ret) {
                        iommufd_ctx_put(iommufd);
                        goto out_unlock;
                }

                group->iommufd = iommufd;
                goto out_unlock;
        }

        /* The FD passed is not recognized. */
        ret = -EBADFD;

out_unlock:
        mutex_unlock(&group->group_lock);
        return ret;
}

static void vfio_device_group_get_kvm_safe(struct vfio_device *device)
{
        spin_lock(&device->group->kvm_ref_lock);
        vfio_device_get_kvm_safe(device, device->group->kvm);
        spin_unlock(&device->group->kvm_ref_lock);
}

static int vfio_df_group_open(struct vfio_device_file *df)
{
        struct vfio_device *device = df->device;
        int ret;

        mutex_lock(&device->group->group_lock);
        if (!vfio_group_has_iommu(device->group)) {
                ret = -EINVAL;
                goto out_unlock;
        }

        mutex_lock(&device->dev_set->lock);

        /*
         * Before the first device open, get the KVM pointer currently
         * associated with the group (if there is one) and obtain a reference
         * now that will be held until the open_count reaches 0 again.  Save
         * the pointer in the device for use by drivers.
         */
        if (device->open_count == 0)
                vfio_device_group_get_kvm_safe(device);

        df->iommufd = device->group->iommufd;
        if (df->iommufd && vfio_device_is_noiommu(device) && device->open_count == 0) {
                /*
                 * Require no compat ioas to be assigned to proceed.  The basic
                 * statement is that the user cannot have done something that
                 * implies they expected translation to exist
                 */
                if (!capable(CAP_SYS_RAWIO) ||
                    vfio_iommufd_device_has_compat_ioas(device, df->iommufd)) {
                        ret = -EPERM;
                        goto out_put_kvm;
                }
        }

        ret = vfio_df_open(df);
        if (ret)
                goto out_put_kvm;

        if (df->iommufd && device->open_count == 1) {
                ret = vfio_iommufd_compat_attach_ioas(device, df->iommufd);
                if (ret)
                        goto out_close_device;
        }

        /*
         * Paired with smp_load_acquire() in vfio_device_fops::ioctl/
         * read/write/mmap and vfio_file_has_device_access()
         */
        smp_store_release(&df->access_granted, true);

        mutex_unlock(&device->dev_set->lock);
        mutex_unlock(&device->group->group_lock);
        return 0;

out_close_device:
        vfio_df_close(df);
out_put_kvm:
        df->iommufd = NULL;
        if (device->open_count == 0)
                vfio_device_put_kvm(device);
        mutex_unlock(&device->dev_set->lock);
out_unlock:
        mutex_unlock(&device->group->group_lock);
        return ret;
}

void vfio_df_group_close(struct vfio_device_file *df)
{
        struct vfio_device *device = df->device;

        mutex_lock(&device->group->group_lock);
        mutex_lock(&device->dev_set->lock);

        vfio_df_close(df);
        df->iommufd = NULL;

        if (device->open_count == 0)
                vfio_device_put_kvm(device);

        mutex_unlock(&device->dev_set->lock);
        mutex_unlock(&device->group->group_lock);
}

static struct file *vfio_device_open_file(struct vfio_device *device)
{
        struct vfio_device_file *df;
        struct file *filep;
        int ret;

        df = vfio_allocate_device_file(device);
        if (IS_ERR(df)) {
                ret = PTR_ERR(df);
                goto err_out;
        }

        df->group = device->group;

        ret = vfio_df_group_open(df);
        if (ret)
                goto err_free;

        filep = anon_inode_getfile_fmode("[vfio-device]", &vfio_device_fops,
                                   df, O_RDWR, FMODE_PREAD | FMODE_PWRITE);
        if (IS_ERR(filep)) {
                ret = PTR_ERR(filep);
                goto err_close_device;
        }
        /*
         * Use the pseudo fs inode on the device to link all mmaps
         * to the same address space, allowing us to unmap all vmas
         * associated to this device using unmap_mapping_range().
         */
        filep->f_mapping = device->inode->i_mapping;

        if (device->group->type == VFIO_NO_IOMMU)
                dev_warn(device->dev, "vfio-noiommu device opened by user "
                         "(%s:%d)\n", current->comm, task_pid_nr(current));
        /*
         * On success the ref of device is moved to the file and
         * put in vfio_device_fops_release()
         */
        return filep;

err_close_device:
        vfio_df_group_close(df);
err_free:
        kfree(df);
err_out:
        return ERR_PTR(ret);
}

static int vfio_group_ioctl_get_device_fd(struct vfio_group *group,
                                          char __user *arg)
{
        struct vfio_device *device;
        char *buf;
        int fd;

        buf = strndup_user(arg, PAGE_SIZE);
        if (IS_ERR(buf))
                return PTR_ERR(buf);

        device = vfio_device_get_from_name(group, buf);
        kfree(buf);
        if (IS_ERR(device))
                return PTR_ERR(device);

        fd = FD_ADD(O_CLOEXEC, vfio_device_open_file(device));
        if (fd < 0)
                vfio_device_put_registration(device);
        return fd;
}

static int vfio_group_ioctl_get_status(struct vfio_group *group,
                                       struct vfio_group_status __user *arg)
{
        unsigned long minsz = offsetofend(struct vfio_group_status, flags);
        struct vfio_group_status status;

        if (copy_from_user(&status, arg, minsz))
                return -EFAULT;

        if (status.argsz < minsz)
                return -EINVAL;

        status.flags = 0;

        mutex_lock(&group->group_lock);
        if (!group->iommu_group) {
                mutex_unlock(&group->group_lock);
                return -ENODEV;
        }

        /*
         * With the container FD the iommu_group_claim_dma_owner() is done
         * during SET_CONTAINER but for IOMMFD this is done during
         * VFIO_GROUP_GET_DEVICE_FD. Meaning that with iommufd
         * VFIO_GROUP_FLAGS_VIABLE could be set but GET_DEVICE_FD will fail due
         * to viability.
         */
        if (vfio_group_has_iommu(group))
                status.flags |= VFIO_GROUP_FLAGS_CONTAINER_SET |
                                VFIO_GROUP_FLAGS_VIABLE;
        else if (!iommu_group_dma_owner_claimed(group->iommu_group))
                status.flags |= VFIO_GROUP_FLAGS_VIABLE;
        mutex_unlock(&group->group_lock);

        if (copy_to_user(arg, &status, minsz))
                return -EFAULT;
        return 0;
}

static long vfio_group_fops_unl_ioctl(struct file *filep,
                                      unsigned int cmd, unsigned long arg)
{
        struct vfio_group *group = filep->private_data;
        void __user *uarg = (void __user *)arg;

        switch (cmd) {
        case VFIO_GROUP_GET_DEVICE_FD:
                return vfio_group_ioctl_get_device_fd(group, uarg);
        case VFIO_GROUP_GET_STATUS:
                return vfio_group_ioctl_get_status(group, uarg);
        case VFIO_GROUP_SET_CONTAINER:
                return vfio_group_ioctl_set_container(group, uarg);
        case VFIO_GROUP_UNSET_CONTAINER:
                return vfio_group_ioctl_unset_container(group);
        default:
                return -ENOTTY;
        }
}

int vfio_device_block_group(struct vfio_device *device)
{
        struct vfio_group *group = device->group;
        int ret = 0;

        mutex_lock(&group->group_lock);
        if (group->opened_file) {
                ret = -EBUSY;
                goto out_unlock;
        }

        group->cdev_device_open_cnt++;

out_unlock:
        mutex_unlock(&group->group_lock);
        return ret;
}

void vfio_device_unblock_group(struct vfio_device *device)
{
        struct vfio_group *group = device->group;

        mutex_lock(&group->group_lock);
        group->cdev_device_open_cnt--;
        mutex_unlock(&group->group_lock);
}

static int vfio_group_fops_open(struct inode *inode, struct file *filep)
{
        struct vfio_group *group =
                container_of(inode->i_cdev, struct vfio_group, cdev);
        int ret;

        mutex_lock(&group->group_lock);

        /*
         * drivers can be zero if this races with vfio_device_remove_group(), it
         * will be stable at 0 under the group rwsem
         */
        if (refcount_read(&group->drivers) == 0) {
                ret = -ENODEV;
                goto out_unlock;
        }

        if (group->type == VFIO_NO_IOMMU && !capable(CAP_SYS_RAWIO)) {
                ret = -EPERM;
                goto out_unlock;
        }

        if (group->cdev_device_open_cnt) {
                ret = -EBUSY;
                goto out_unlock;
        }

        /*
         * Do we need multiple instances of the group open?  Seems not.
         */
        if (group->opened_file) {
                ret = -EBUSY;
                goto out_unlock;
        }
        group->opened_file = filep;
        filep->private_data = group;
        ret = 0;
out_unlock:
        mutex_unlock(&group->group_lock);
        return ret;
}

static int vfio_group_fops_release(struct inode *inode, struct file *filep)
{
        struct vfio_group *group = filep->private_data;

        filep->private_data = NULL;

        mutex_lock(&group->group_lock);
        /*
         * Device FDs hold a group file reference, therefore the group release
         * is only called when there are no open devices.
         */
        WARN_ON(group->notifier.head);
        if (group->container)
                vfio_group_detach_container(group);
        if (group->iommufd) {
                iommufd_ctx_put(group->iommufd);
                group->iommufd = NULL;
        }
        group->opened_file = NULL;
        mutex_unlock(&group->group_lock);
        return 0;
}

static const struct file_operations vfio_group_fops = {
        .owner          = THIS_MODULE,
        .unlocked_ioctl = vfio_group_fops_unl_ioctl,
        .compat_ioctl   = compat_ptr_ioctl,
        .open           = vfio_group_fops_open,
        .release        = vfio_group_fops_release,
};

/*
 * Group objects - create, release, get, put, search
 */
static struct vfio_group *
vfio_group_find_from_iommu(struct iommu_group *iommu_group)
{
        struct vfio_group *group;

        lockdep_assert_held(&vfio.group_lock);

        /*
         * group->iommu_group from the vfio.group_list cannot be NULL
         * under the vfio.group_lock.
         */
        list_for_each_entry(group, &vfio.group_list, vfio_next) {
                if (group->iommu_group == iommu_group)
                        return group;
        }
        return NULL;
}

static void vfio_group_release(struct device *dev)
{
        struct vfio_group *group = container_of(dev, struct vfio_group, dev);

        mutex_destroy(&group->device_lock);
        mutex_destroy(&group->group_lock);
        WARN_ON(group->iommu_group);
        WARN_ON(group->cdev_device_open_cnt);
        ida_free(&vfio.group_ida, MINOR(group->dev.devt));
        kfree(group);
}

static struct vfio_group *vfio_group_alloc(struct iommu_group *iommu_group,
                                           enum vfio_group_type type)
{
        struct vfio_group *group;
        int minor;

        group = kzalloc_obj(*group);
        if (!group)
                return ERR_PTR(-ENOMEM);

        minor = ida_alloc_max(&vfio.group_ida, MINORMASK, GFP_KERNEL);
        if (minor < 0) {
                kfree(group);
                return ERR_PTR(minor);
        }

        device_initialize(&group->dev);
        group->dev.devt = MKDEV(MAJOR(vfio.group_devt), minor);
        group->dev.class = vfio.class;
        group->dev.release = vfio_group_release;
        cdev_init(&group->cdev, &vfio_group_fops);
        group->cdev.owner = THIS_MODULE;

        refcount_set(&group->drivers, 1);
        mutex_init(&group->group_lock);
        spin_lock_init(&group->kvm_ref_lock);
        INIT_LIST_HEAD(&group->device_list);
        mutex_init(&group->device_lock);
        group->iommu_group = iommu_group;
        /* put in vfio_group_release() */
        iommu_group_ref_get(iommu_group);
        group->type = type;
        BLOCKING_INIT_NOTIFIER_HEAD(&group->notifier);

        return group;
}

static struct vfio_group *vfio_create_group(struct iommu_group *iommu_group,
                enum vfio_group_type type)
{
        struct vfio_group *group;
        struct vfio_group *ret;
        int err;

        lockdep_assert_held(&vfio.group_lock);

        group = vfio_group_alloc(iommu_group, type);
        if (IS_ERR(group))
                return group;

        err = dev_set_name(&group->dev, "%s%d",
                           group->type == VFIO_NO_IOMMU ? "noiommu-" : "",
                           iommu_group_id(iommu_group));
        if (err) {
                ret = ERR_PTR(err);
                goto err_put;
        }

        err = cdev_device_add(&group->cdev, &group->dev);
        if (err) {
                ret = ERR_PTR(err);
                goto err_put;
        }

        list_add(&group->vfio_next, &vfio.group_list);

        return group;

err_put:
        put_device(&group->dev);
        return ret;
}

static struct vfio_group *vfio_noiommu_group_alloc(struct device *dev,
                enum vfio_group_type type)
{
        struct iommu_group *iommu_group;
        struct vfio_group *group;
        int ret;

        iommu_group = iommu_group_alloc();
        if (IS_ERR(iommu_group))
                return ERR_CAST(iommu_group);

        ret = iommu_group_set_name(iommu_group, "vfio-noiommu");
        if (ret)
                goto out_put_group;
        ret = iommu_group_add_device(iommu_group, dev);
        if (ret)
                goto out_put_group;

        mutex_lock(&vfio.group_lock);
        group = vfio_create_group(iommu_group, type);
        mutex_unlock(&vfio.group_lock);
        if (IS_ERR(group)) {
                ret = PTR_ERR(group);
                goto out_remove_device;
        }
        iommu_group_put(iommu_group);
        return group;

out_remove_device:
        iommu_group_remove_device(dev);
out_put_group:
        iommu_group_put(iommu_group);
        return ERR_PTR(ret);
}

static bool vfio_group_has_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) {
                        mutex_unlock(&group->device_lock);
                        return true;
                }
        }
        mutex_unlock(&group->device_lock);
        return false;
}

static struct vfio_group *vfio_group_find_or_alloc(struct device *dev)
{
        struct iommu_group *iommu_group;
        struct vfio_group *group;

        iommu_group = iommu_group_get(dev);
        if (!iommu_group && vfio_noiommu) {
                /*
                 * With noiommu enabled, create an IOMMU group for devices that
                 * don't already have one, implying no IOMMU hardware/driver
                 * exists.  Taint the kernel because we're about to give a DMA
                 * capable device to a user without IOMMU protection.
                 */
                group = vfio_noiommu_group_alloc(dev, VFIO_NO_IOMMU);
                if (!IS_ERR(group)) {
                        add_taint(TAINT_USER, LOCKDEP_STILL_OK);
                        dev_warn(dev, "Adding kernel taint for vfio-noiommu group on device\n");
                }
                return group;
        }

        if (!iommu_group)
                return ERR_PTR(-EINVAL);

        mutex_lock(&vfio.group_lock);
        group = vfio_group_find_from_iommu(iommu_group);
        if (group) {
                if (WARN_ON(vfio_group_has_device(group, dev)))
                        group = ERR_PTR(-EINVAL);
                else
                        refcount_inc(&group->drivers);
        } else {
                group = vfio_create_group(iommu_group, VFIO_IOMMU);
        }
        mutex_unlock(&vfio.group_lock);

        /* The vfio_group holds a reference to the iommu_group */
        iommu_group_put(iommu_group);
        return group;
}

int vfio_device_set_group(struct vfio_device *device,
                          enum vfio_group_type type)
{
        struct vfio_group *group;

        if (type == VFIO_IOMMU)
                group = vfio_group_find_or_alloc(device->dev);
        else
                group = vfio_noiommu_group_alloc(device->dev, type);

        if (IS_ERR(group))
                return PTR_ERR(group);

        /* Our reference on group is moved to the device */
        device->group = group;
        return 0;
}

void vfio_device_remove_group(struct vfio_device *device)
{
        struct vfio_group *group = device->group;
        struct iommu_group *iommu_group;

        if (group->type == VFIO_NO_IOMMU || group->type == VFIO_EMULATED_IOMMU)
                iommu_group_remove_device(device->dev);

        /* Pairs with vfio_create_group() / vfio_group_get_from_iommu() */
        if (!refcount_dec_and_mutex_lock(&group->drivers, &vfio.group_lock))
                return;
        list_del(&group->vfio_next);

        /*
         * We could concurrently probe another driver in the group that might
         * race vfio_device_remove_group() with vfio_get_group(), so we have to
         * ensure that the sysfs is all cleaned up under lock otherwise the
         * cdev_device_add() will fail due to the name aready existing.
         */
        cdev_device_del(&group->cdev, &group->dev);

        mutex_lock(&group->group_lock);
        /*
         * These data structures all have paired operations that can only be
         * undone when the caller holds a live reference on the device. Since
         * all pairs must be undone these WARN_ON's indicate some caller did not
         * properly hold the group reference.
         */
        WARN_ON(!list_empty(&group->device_list));
        WARN_ON(group->notifier.head);

        /*
         * Revoke all users of group->iommu_group. At this point we know there
         * are no devices active because we are unplugging the last one. Setting
         * iommu_group to NULL blocks all new users.
         */
        if (group->container)
                vfio_group_detach_container(group);
        iommu_group = group->iommu_group;
        group->iommu_group = NULL;
        mutex_unlock(&group->group_lock);
        mutex_unlock(&vfio.group_lock);

        iommu_group_put(iommu_group);
        put_device(&group->dev);
}

void vfio_device_group_register(struct vfio_device *device)
{
        mutex_lock(&device->group->device_lock);
        list_add(&device->group_next, &device->group->device_list);
        mutex_unlock(&device->group->device_lock);
}

void vfio_device_group_unregister(struct vfio_device *device)
{
        mutex_lock(&device->group->device_lock);
        list_del(&device->group_next);
        mutex_unlock(&device->group->device_lock);
}

int vfio_device_group_use_iommu(struct vfio_device *device)
{
        struct vfio_group *group = device->group;
        int ret = 0;

        lockdep_assert_held(&group->group_lock);

        if (WARN_ON(!group->container))
                return -EINVAL;

        ret = vfio_group_use_container(group);
        if (ret)
                return ret;
        vfio_device_container_register(device);
        return 0;
}

void vfio_device_group_unuse_iommu(struct vfio_device *device)
{
        struct vfio_group *group = device->group;

        lockdep_assert_held(&group->group_lock);

        if (WARN_ON(!group->container))
                return;

        vfio_device_container_unregister(device);
        vfio_group_unuse_container(group);
}

bool vfio_device_has_container(struct vfio_device *device)
{
        return device->group->container;
}

struct vfio_group *vfio_group_from_file(struct file *file)
{
        struct vfio_group *group = file->private_data;

        if (file->f_op != &vfio_group_fops)
                return NULL;
        return group;
}

/**
 * vfio_file_iommu_group - Return the struct iommu_group for the vfio group file
 * @file: VFIO group file
 *
 * The returned iommu_group is valid as long as a ref is held on the file. This
 * returns a reference on the group. This function is deprecated, only the SPAPR
 * path in kvm should call it.
 */
struct iommu_group *vfio_file_iommu_group(struct file *file)
{
        struct vfio_group *group = vfio_group_from_file(file);
        struct iommu_group *iommu_group = NULL;

        if (!IS_ENABLED(CONFIG_SPAPR_TCE_IOMMU))
                return NULL;

        if (!group)
                return NULL;

        mutex_lock(&group->group_lock);
        if (group->iommu_group) {
                iommu_group = group->iommu_group;
                iommu_group_ref_get(iommu_group);
        }
        mutex_unlock(&group->group_lock);
        return iommu_group;
}
EXPORT_SYMBOL_GPL(vfio_file_iommu_group);

/**
 * vfio_file_is_group - True if the file is a vfio group file
 * @file: VFIO group file
 */
bool vfio_file_is_group(struct file *file)
{
        return vfio_group_from_file(file);
}
EXPORT_SYMBOL_GPL(vfio_file_is_group);

bool vfio_group_enforced_coherent(struct vfio_group *group)
{
        struct vfio_device *device;
        bool ret = true;

        /*
         * If the device does not have IOMMU_CAP_ENFORCE_CACHE_COHERENCY then
         * any domain later attached to it will also not support it. If the cap
         * is set then the iommu_domain eventually attached to the device/group
         * must use a domain with enforce_cache_coherency().
         */
        mutex_lock(&group->device_lock);
        list_for_each_entry(device, &group->device_list, group_next) {
                if (!device_iommu_capable(device->dev,
                                          IOMMU_CAP_ENFORCE_CACHE_COHERENCY)) {
                        ret = false;
                        break;
                }
        }
        mutex_unlock(&group->device_lock);
        return ret;
}

void vfio_group_set_kvm(struct vfio_group *group, struct kvm *kvm)
{
        spin_lock(&group->kvm_ref_lock);
        group->kvm = kvm;
        spin_unlock(&group->kvm_ref_lock);
}

/**
 * vfio_file_has_dev - True if the VFIO file is a handle for device
 * @file: VFIO file to check
 * @device: Device that must be part of the file
 *
 * Returns true if given file has permission to manipulate the given device.
 */
bool vfio_file_has_dev(struct file *file, struct vfio_device *device)
{
        struct vfio_group *group = vfio_group_from_file(file);

        if (!group)
                return false;

        return group == device->group;
}
EXPORT_SYMBOL_GPL(vfio_file_has_dev);

static char *vfio_devnode(const struct device *dev, umode_t *mode)
{
        return kasprintf(GFP_KERNEL, "vfio/%s", dev_name(dev));
}

int __init vfio_group_init(void)
{
        int ret;

        ida_init(&vfio.group_ida);
        mutex_init(&vfio.group_lock);
        INIT_LIST_HEAD(&vfio.group_list);

        ret = vfio_container_init();
        if (ret)
                return ret;

        /* /dev/vfio/$GROUP */
        vfio.class = class_create("vfio");
        if (IS_ERR(vfio.class)) {
                ret = PTR_ERR(vfio.class);
                goto err_group_class;
        }

        vfio.class->devnode = vfio_devnode;

        ret = alloc_chrdev_region(&vfio.group_devt, 0, MINORMASK + 1, "vfio");
        if (ret)
                goto err_alloc_chrdev;
        return 0;

err_alloc_chrdev:
        class_destroy(vfio.class);
        vfio.class = NULL;
err_group_class:
        vfio_container_cleanup();
        return ret;
}

void vfio_group_cleanup(void)
{
        WARN_ON(!list_empty(&vfio.group_list));
        ida_destroy(&vfio.group_ida);
        unregister_chrdev_region(vfio.group_devt, MINORMASK + 1);
        class_destroy(vfio.class);
        vfio.class = NULL;
        vfio_container_cleanup();
}