> @@ -2629,6 +2638,46 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
>               }
>               kfree(gbind_data);
>               return ret;
> +     } else if (cmd == VFIO_IOMMU_CACHE_INVALIDATE) {

Please refactor the spaghetti in this ioctl handler to use a switch
statement and a helper function per command before growing it even more.

> +             /* Get the version of struct iommu_cache_invalidate_info */
> +             if (copy_from_user(&version,
> +                     (void __user *) (arg + minsz), sizeof(version)))
> +                     return -EFAULT;
> +
> +             info_size = iommu_uapi_get_data_size(
> +                                     IOMMU_UAPI_CACHE_INVAL, version);
> +
> +             cache_info = kzalloc(info_size, GFP_KERNEL);
> +             if (!cache_info)
> +                     return -ENOMEM;
> +
> +             if (copy_from_user(cache_info,
> +                     (void __user *) (arg + minsz), info_size)) {

The user might have changed the version while you were allocating and
freeing the memory, introducing potentially exploitable racing
conditions.
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