Re: [PATCH v2 7/7] drm/virtio: implement userptr: add interval tree

[Dmitry Osipenko]

If the purpose of this feature is to dedup usrptr BOs of a the single
process/application, can this can be done in userspace?

On 3/21/25 11:00, Honglei Huang wrote:
>  int virtio_gpu_userptr_create(struct virtio_gpu_device *vgdev,
>  			      struct drm_file *file,
>  			      struct virtio_gpu_object_params *params,
> -			      struct virtio_gpu_object **bo_ptr)
> +			      struct virtio_gpu_object **bo_ptr,
> +			      struct drm_virtgpu_resource_create_blob *rc_blob)
>  {
> +	struct virtio_gpu_fpriv *vfpriv = file->driver_priv;
>  	struct virtio_gpu_object_userptr *userptr;
>  	int ret, si;
>  	struct sg_table *sgt;
> @@ -187,6 +290,20 @@ int virtio_gpu_userptr_create(struct virtio_gpu_device *vgdev,
>  		       params->size))
>  		return -EFAULT;
>  
> +	mutex_lock(&vfpriv->userptrs_tree_lock);
> +
> +	userptr = virtio_gpu_userptr_from_addr_range(
> +		vfpriv, params->userptr, params->userptr + params->size - 1UL);

Is it possible that userptr address will be same for two different
processes?

What if userptr->flags mismatch?

> +	if (userptr) {
> +		*bo_ptr = &userptr->base;
> +		rc_blob->res_handle = userptr->base.hw_res_handle;
> +		rc_blob->bo_handle = userptr->bo_handle;

Doesn't BO refcount need to be bumped?

> +		rc_blob->offset = virtio_gpu_userptr_get_offset(
> +			&userptr->base, rc_blob->userptr);
> +		mutex_unlock(&vfpriv->userptrs_tree_lock);
> +		return STATE_RES_EXISTS;

STATE_RES_EXISTS isn't a error code

-- 
Best regards,
Dmitry