From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joerg Roedel Subject: Re: [RFC] Independent use of IOMMU groups Date: Fri, 6 Nov 2015 13:29:40 +0100 Message-ID: <20151106122939.GA13027@8bytes.org> References: <1446746079.8831.82.camel@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1446746079.8831.82.camel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Alex Williamson Cc: Paolo Bonzini , iommu List-Id: iommu@lists.linux-foundation.org Hi Alex, On Thu, Nov 05, 2015 at 10:54:39AM -0700, Alex Williamson wrote: > We have a couple things in-flight that are trying to make use of IOMMU > groups, independent of the rest of the IOMMU API. One is the proposed > VFIO No-IOMMU hack that will create an IOMMU group for a non-IOMMU > backed device in order to make it operate within vfio and exposed via > vfio-pci: > > https://lkml.org/lkml/2015/11/4/437 Do you really need iommu-groups for non-IOMMU vfio backend? VFIO has its own representation of groups (iirc they map 1-1 to iommu-groups). Can this concept in VFIO not be made more independent of iommu-groups? I think having iommu-groups in sysfs without an iommu in the system is pretty confusing for the user. Not to say that the usual iommu grouping code makes no sense anymore, as there is no isolation at all :) Joerg