> From: Nicolin Chen <nicolinc@xxxxxxxxxx> > Sent: Saturday, January 28, 2023 4:04 AM > > Both IOMMU_DOMAIN_UNMANAGED and IOMMU_DOMAIN_DMA require > the support > of __IOMMU_DOMAIN_PAGING capability, i.e. iommu_map/unmap. > However, > some older iommu drivers do not fully support that, and these drivers > also do not advertise support for dma-iommu.c via IOMMU_DOMAIN_DMA, > or use arm_iommu_create_mapping(), so largely their implementations > of IOMMU_DOMAIN_UNMANAGED are untested. This means that a user like > vfio/iommufd does not likely work with them. > > Several of them have obvious problems: > * fsl_pamu_domain.c > Without map/unmap ops in the default_domain_ops, it isn't an > unmanaged domain at all. > * mtk_iommu_v1.c > With a fixed 4M "pagetable", it can only map exactly 4G of > memory, but doesn't set the aperture. > * tegra-gart.c > Its notion of attach/detach and groups has to be a complete lie to > get around all the other API expectations. > > Some others might work but have never been tested with vfio/iommufd: > * msm_iommu.c > * omap-iommu.c > * tegra-smmu.c > Do we have a link where all drivers tested with vfio/iommufd have been listed? In a quick glance at least exynos-iommu.c and apple-dart.c both support UNMANAGED with map/unmap ops. They are not mentioned in above list but I doubt they are tested for vfio/iommufd.
