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 -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
