From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from rcdn-iport-5.cisco.com (rcdn-iport-5.cisco.com [173.37.86.76]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "rcdn-iport-5.cisco.com", Issuer "Cisco SSCA2" (verified OK)) by ozlabs.org (Postfix) with ESMTPS id 3420BB7091 for ; Wed, 24 Aug 2011 02:54:34 +1000 (EST) Date: Tue, 23 Aug 2011 09:54:27 -0700 Subject: Re: kvm PCI assignment & VFIO ramblings From: aafabbri To: Joerg Roedel Message-ID: In-Reply-To: <20110823110431.GK2079@amd.com> Mime-version: 1.0 Content-type: text/plain; charset="US-ASCII" Cc: 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" List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 8/23/11 4:04 AM, "Joerg Roedel" wrote: > On Mon, Aug 22, 2011 at 08:52:18PM -0400, aafabbri wrote: >> You have to enforce group/iommu domain assignment whether you have the >> existing uiommu API, or if you change it to your proposed >> ioctl(inherit_iommu) API. >> >> The only change needed to VFIO here should be to make uiommu fd assignment >> happen on the groups instead of on device fds. That operation fails or >> succeeds according to the group semantics (all-or-none assignment/same >> uiommu). > > 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. -Aaron Fabbri