From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Gibson Subject: Re: kvm PCI assignment & VFIO ramblings Date: Wed, 24 Aug 2011 19:33:00 +1000 Message-ID: <20110824093300.GI30097@yookeroo.fritz.box> References: <20110823110431.GK2079@amd.com> <20110824091425.GE2079@amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: aafabbri , Alexey Kardashevskiy , "kvm@vger.kernel.org" , Paul Mackerras , "linux-pci@vger.kernel.org" , qemu-devel , chrisw , iommu , Avi Kivity , Anthony Liguori , linuxppc-dev , "benve@cisco.com" To: "Roedel, Joerg" Return-path: Content-Disposition: inline In-Reply-To: <20110824091425.GE2079@amd.com> Sender: linux-pci-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On Wed, Aug 24, 2011 at 11:14:26AM +0200, Roedel, Joerg wrote: > On Tue, Aug 23, 2011 at 12:54:27PM -0400, aafabbri wrote: > > On 8/23/11 4:04 AM, "Joerg Roedel" wrote: > > > That is makes uiommu basically the same as the meta-groups, right? > > > > Yes, functionality seems the same, thus my suggestion to keep uiommu > > explicit. Is there some need for group-groups besides defining sets of > > groups which share IOMMU resources? > > > > I do all this stuff (bringing up sets of devices which may share IOMMU > > domain) dynamically from C applications. I don't really want some static > > (boot-time or sysfs fiddling) supergroup config unless there is a good > > reason KVM/power needs it. > > > > As you say in your next email, doing it all from ioctls is very easy, > > programmatically. > > I don't see a reason to make this meta-grouping static. It would harm > flexibility on x86. I think it makes things easier on power but there > are options on that platform to get the dynamic solution too. I think several people are misreading what Ben means by "static". I would prefer to say 'persistent', in that the meta-groups lifetime is not tied to an fd, but they can be freely created, altered and removed during runtime. -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson