Hi Valmiki, On 12/09/17 19:01, valmiki wrote: > Hi, as per VFIO documentation i see that we need to see > "/sys/bus/pci/devices/0000:06:0d.0/iommu_group" in order to find group > in which PCI bus is attached. > But as per drivers/pci/pci-sysfs.c in static struct attribute > *pci_dev_attrs[], i don't see any such attribute. This iommu_group attribute is created by drivers/iommu/iommu.c:iommu_group_add_device. It is a symbolic link to /sys/kernel/iommu_groups/<group>. > I tried enabling SMMUv2 driver and SMMU for PCIe node on our SOC, but > this file doesn't show up and also in /sys/kernel/iommu_group i do not > see "/sys/kernel/iommu_groups/17/devices/0000:00:1f.00" file, i see only > PCIe root port device tree node in that group and not individual buses. > So on ARM64 for showing these paths i.e show specific to each bus, does > SMMU need any particular confguration (we have SMMUv2) > Do we need any specific kernel configuration ? I don't think so. If you're able to see the root complex in an IOMMU group, then the configuration is probably fine. Could you provide a little more information about your system, for example lspci along with "find /sys/kernel/iommu_groups/*/devices/*"? Ideally, each PCIe device will be in its own IOMMU group. So you shouldn't have each bus in a group, but rather one device per group. Linux puts multiple devices in a group if the IOMMU cannot properly isolate them. In general it's not something you want in your system, because all devices in a group will have the same address space and cannot be passed to a guest separately. Thanks, Jean
