From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:59977) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QvuFI-0003go-5i for qemu-devel@nongnu.org; Tue, 23 Aug 2011 12:54:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QvuFG-0005KU-NT for qemu-devel@nongnu.org; Tue, 23 Aug 2011 12:54:36 -0400 Received: from rcdn-iport-5.cisco.com ([173.37.86.76]:48384) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QvuFG-0005JZ-GF for qemu-devel@nongnu.org; Tue, 23 Aug 2011 12:54:34 -0400 Date: Tue, 23 Aug 2011 09:54:27 -0700 From: aafabbri Message-ID: In-Reply-To: <20110823110431.GK2079@amd.com> Mime-version: 1.0 Content-type: text/plain; charset="US-ASCII" Content-transfer-encoding: 7bit Subject: Re: [Qemu-devel] kvm PCI assignment & VFIO ramblings List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Joerg Roedel Cc: Alexey Kardashevskiy , "kvm@vger.kernel.org" , Paul Mackerras , "linux-pci@vger.kernel.org" , qemu-devel , chrisw , iommu , Avi Kivity , linuxppc-dev , "benve@cisco.com" 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