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I think for now we should disable DMABUF for any PCI driver that implements a VFIO_DEVICE_GET_REGION_INFO For a while I've wanted to further reduce the use of the ioctl multiplexer, so maybe this series: https://github.com/jgunthorpe/linux/commits/vfio_get_region_info_op/ And then the dmabuf code can check if the ops are set to the generic or not and disable itself automatically. Otherwise perhaps route the dmabuf through an op and deliberately omit it (with a comment!) from hisi, virtio, nvgrace. We need to route it through an op anyhow as those three drivers will probably eventually want to implement their own version. Jason