From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:35443) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QvS4O-0000dQ-FN for qemu-devel@nongnu.org; Mon, 22 Aug 2011 06:49:29 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QvS4N-0005Lt-Ed for qemu-devel@nongnu.org; Mon, 22 Aug 2011 06:49:28 -0400 Received: from tx2ehsobe004.messaging.microsoft.com ([65.55.88.14]:48235 helo=TX2EHSOBE008.bigfish.com) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QvS4N-0005Ld-AE for qemu-devel@nongnu.org; Mon, 22 Aug 2011 06:49:27 -0400 Date: Mon, 22 Aug 2011 12:46:35 +0200 From: Joerg Roedel Message-ID: <20110822104635.GC2079@amd.com> References: <1312050011.2265.185.camel@x201.home> <20110802082848.GD29719@yookeroo.fritz.box> <1312308847.2653.467.camel@bling.home> <1312310121.2653.470.camel@bling.home> <20110803020422.GF29719@yookeroo.fritz.box> <4E3F9E33.5000706@redhat.com> <1312932258.4524.55.camel@bling.home> <1312944513.29273.28.camel@pasglop> <1313859105.6866.192.camel@x201.home> <4E51F782.7060005@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <4E51F782.7060005@redhat.com> Subject: Re: [Qemu-devel] kvm PCI assignment & VFIO ramblings List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Avi Kivity Cc: Alexey Kardashevskiy , "kvm@vger.kernel.org" , Paul Mackerras , qemu-devel , iommu , chrisw , Alex Williamson , "linux-pci@vger.kernel.org" , linuxppc-dev , "benve@cisco.com" On Mon, Aug 22, 2011 at 02:30:26AM -0400, Avi Kivity wrote: > On 08/20/2011 07:51 PM, Alex Williamson wrote: > > We need to address both the description and enforcement of device > > groups. Groups are formed any time the iommu does not have resolution > > between a set of devices. On x86, this typically happens when a > > PCI-to-PCI bridge exists between the set of devices and the iommu. For > > Power, partitionable endpoints define a group. Grouping information > > needs to be exposed for both userspace and kernel internal usage. This > > will be a sysfs attribute setup by the iommu drivers. Perhaps: > > > > # cat /sys/devices/pci0000:00/0000:00:19.0/iommu_group > > 42 > > > > $ readlink /sys/devices/pci0000:00/0000:00:19.0/iommu_group > ../../../path/to/device/which/represents/the/resource/constraint > > (the pci-to-pci bridge on x86, or whatever node represents partitionable > endpoints on power) That does not work. The bridge in question may not even be visible as a PCI device, so you can't link to it. This is the case on a few PCIe cards which only have a PCIx chip and a PCIe-2-PCIx bridge to implement the PCIe interface (yes, I have seen those cards). Regards, Joerg -- AMD Operating System Research Center Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach General Managers: Alberto Bozzo, Andrew Bowd Registration: Dornach, Landkr. Muenchen; Registerger. Muenchen, HRB Nr. 43632