Actually, XEN mostly reserves the use of IOMMU for itself. On the other hand, some widely used Linux frameworks (such as VFIO) could need to access/modify IOMMU contexts for devices. We try to understand if it is usefull to provide such access to privileged domains and if so, could we agree on the way of doing this (paravirtualized IOMMU driver in Linux kernel?) as well of the perimeter of such an interface.