On Mon, Jan 8, 2018 at 11:57 AM, Christoph Hellwig <hch@xxxxxx> wrote: >> (c) setup/manage any security permissions on mappings >> Which P2P may at some point be concerned with. > > Maybe once root complexes with iommus actually support P2P. But until > then we have a lot more more important problems to solve. Pretty sure P2P capable IOMMU hardware exists. With SOC's we also have the scenario that an DMA originated from an on-die device wishes to target an off-die PCI BAR (through the IOMMU), that definitely exists today, and people care about it :) Jason
