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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2023 Intel Corporation.
*/
#include <linux/vfio.h>
#include <linux/iommufd.h>
#include "vfio.h"
static dev_t device_devt;
void vfio_init_device_cdev(struct vfio_device *device)
{
device->device.devt = MKDEV(MAJOR(device_devt), device->index);
cdev_init(&device->cdev, &vfio_device_fops);
device->cdev.owner = THIS_MODULE;
}
/*
* device access via the fd opened by this function is blocked until
* .open_device() is called successfully during BIND_IOMMUFD.
*/
int vfio_device_fops_cdev_open(struct inode *inode, struct file *filep)
{
struct vfio_device *device = container_of(inode->i_cdev,
struct vfio_device, cdev);
struct vfio_device_file *df;
int ret;
/* Paired with the put in vfio_device_fops_release() */
if (!vfio_device_try_get_registration(device))
return -ENODEV;
df = vfio_allocate_device_file(device);
if (IS_ERR(df)) {
ret = PTR_ERR(df);
goto err_put_registration;
}
filep->private_data = df;
return 0;
err_put_registration:
vfio_device_put_registration(device);
return ret;
}
static void vfio_df_get_kvm_safe(struct vfio_device_file *df)
{
spin_lock(&df->kvm_ref_lock);
vfio_device_get_kvm_safe(df->device, df->kvm);
spin_unlock(&df->kvm_ref_lock);
}
long vfio_df_ioctl_bind_iommufd(struct vfio_device_file *df,
struct vfio_device_bind_iommufd __user *arg)
{
struct vfio_device *device = df->device;
struct vfio_device_bind_iommufd bind;
unsigned long minsz;
int ret;
static_assert(__same_type(arg->out_devid, df->devid));
minsz = offsetofend(struct vfio_device_bind_iommufd, out_devid);
if (copy_from_user(&bind, arg, minsz))
return -EFAULT;
if (bind.argsz < minsz || bind.flags || bind.iommufd < 0)
return -EINVAL;
/* BIND_IOMMUFD only allowed for cdev fds */
if (df->group)
return -EINVAL;
ret = vfio_device_block_group(device);
if (ret)
return ret;
mutex_lock(&device->dev_set->lock);
/* one device cannot be bound twice */
if (df->access_granted) {
ret = -EINVAL;
goto out_unlock;
}
df->iommufd = iommufd_ctx_from_fd(bind.iommufd);
if (IS_ERR(df->iommufd)) {
ret = PTR_ERR(df->iommufd);
df->iommufd = NULL;
goto out_unlock;
}
/*
* Before the device open, get the KVM pointer currently
* associated with the device file (if there is) and obtain
* a reference. This reference is held until device closed.
* Save the pointer in the device for use by drivers.
*/
vfio_df_get_kvm_safe(df);
ret = vfio_df_open(df);
if (ret)
goto out_put_kvm;
ret = copy_to_user(&arg->out_devid, &df->devid,
sizeof(df->devid)) ? -EFAULT : 0;
if (ret)
goto out_close_device;
device->cdev_opened = true;
/*
* Paired with smp_load_acquire() in vfio_device_fops::ioctl/
* read/write/mmap
*/
smp_store_release(&df->access_granted, true);
mutex_unlock(&device->dev_set->lock);
return 0;
out_close_device:
vfio_df_close(df);
out_put_kvm:
vfio_device_put_kvm(device);
iommufd_ctx_put(df->iommufd);
df->iommufd = NULL;
out_unlock:
mutex_unlock(&device->dev_set->lock);
vfio_device_unblock_group(device);
return ret;
}
void vfio_df_unbind_iommufd(struct vfio_device_file *df)
{
struct vfio_device *device = df->device;
/*
* In the time of close, there is no contention with another one
* changing this flag. So read df->access_granted without lock
* and no smp_load_acquire() is ok.
*/
if (!df->access_granted)
return;
mutex_lock(&device->dev_set->lock);
vfio_df_close(df);
vfio_device_put_kvm(device);
iommufd_ctx_put(df->iommufd);
device->cdev_opened = false;
mutex_unlock(&device->dev_set->lock);
vfio_device_unblock_group(device);
}
int vfio_df_ioctl_attach_pt(struct vfio_device_file *df,
struct vfio_device_attach_iommufd_pt __user *arg)
{
struct vfio_device *device = df->device;
struct vfio_device_attach_iommufd_pt attach;
unsigned long minsz;
int ret;
minsz = offsetofend(struct vfio_device_attach_iommufd_pt, pt_id);
if (copy_from_user(&attach, arg, minsz))
return -EFAULT;
if (attach.argsz < minsz || attach.flags)
return -EINVAL;
mutex_lock(&device->dev_set->lock);
ret = device->ops->attach_ioas(device, &attach.pt_id);
if (ret)
goto out_unlock;
if (copy_to_user(&arg->pt_id, &attach.pt_id, sizeof(attach.pt_id))) {
ret = -EFAULT;
goto out_detach;
}
mutex_unlock(&device->dev_set->lock);
return 0;
out_detach:
device->ops->detach_ioas(device);
out_unlock:
mutex_unlock(&device->dev_set->lock);
return ret;
}
int vfio_df_ioctl_detach_pt(struct vfio_device_file *df,
struct vfio_device_detach_iommufd_pt __user *arg)
{
struct vfio_device *device = df->device;
struct vfio_device_detach_iommufd_pt detach;
unsigned long minsz;
minsz = offsetofend(struct vfio_device_detach_iommufd_pt, flags);
if (copy_from_user(&detach, arg, minsz))
return -EFAULT;
if (detach.argsz < minsz || detach.flags)
return -EINVAL;
mutex_lock(&device->dev_set->lock);
device->ops->detach_ioas(device);
mutex_unlock(&device->dev_set->lock);
return 0;
}
static char *vfio_device_devnode(const struct device *dev, umode_t *mode)
{
return kasprintf(GFP_KERNEL, "vfio/devices/%s", dev_name(dev));
}
int vfio_cdev_init(struct class *device_class)
{
device_class->devnode = vfio_device_devnode;
return alloc_chrdev_region(&device_devt, 0,
MINORMASK + 1, "vfio-dev");
}
void vfio_cdev_cleanup(void)
{
unregister_chrdev_region(device_devt, MINORMASK + 1);
}
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