> From: Nicolin Chen <nicolinc@xxxxxxxxxx> > Sent: Saturday, January 28, 2023 4:04 AM > > Hi all, > > 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. > > Thus, mark all these drivers as having "broken" UNAMANGED domains and > add a new device_iommu_unmanaged_supported() API for vfio/iommufd > and > dma-iommu to refuse to work with these drivers. > Why not making an explicit way to mark which drivers are tested to support vfio/iommufd? Not sure whether pure code review is reliable to filter out 'broken' vs. 'non-broken'...
