RE: [PATCH v4 2/9] vfio-iommufd: Create iommufd_access for noiommu devices

Tian, Kevin
2023-04-27T06:39:20Z

> From: Liu, Yi L <yi.l.liu@intel.com>
> Sent: Wednesday, April 26, 2023 10:54 PM
> @@ -121,7 +128,8 @@ static void vfio_emulated_unmap(void *data,
> unsigned long iova,
> {
> struct vfio_device *vdev = data;
>
> - if (vdev->ops->dma_unmap)
> + /* noiommu devices cannot do map/unmap */
> + if (vdev->noiommu && vdev->ops->dma_unmap)
> vdev->ops->dma_unmap(vdev, iova, length);

Is it necessary? All mdev devices implementing @dma_unmap won't
set noiommu flag.

Instead in the future if we allow noiommu userspace to pin pages
we'd need similar logic too.