On 05/28/2016 10:56 PM, Alex Williamson wrote: > On Fri, 27 May 2016 22:43:54 +0000 > "Tian, Kevin" <kevin.t...@intel.com> wrote: > >> >> My impression was that you don't like hypervisor specific thing in VFIO, >> which makes it a bit tricky to accomplish those tasks in kernel. If we >> can add Xen specific logic directly in VFIO (like vfio-iommu-xen you >> mentioned), the whole thing would be easier. > > If vfio is hosted in dom0, then Xen is the platform and we need to > interact with the hypervisor to manage the iommu. That said, there are > aspects of vfio that do not seem to map well to a hypervisor managed > iommu or a Xen-like hypervisor. For instance, how does dom0 manage > iommu groups and what's the distinction of using vfio to manage a > userspace driver in dom0 versus managing a device for another domain. > In the case of kvm, vfio has no dependency on kvm, there is some minor > interaction, but we're not running on kvm and it's not appropriate to > use vfio as a gateway to interact with a hypervisor that may or may not > exist. Thanks,
Hi Alex, Beyond iommu, there are other aspects vfio need to interact with Xen? e.g. to pass-through MMIO, one have to call hypercalls to establish EPT mappings. -- Thanks, Jike
