On Wed, Apr 20, 2016 at 06:33:54PM +0100, Marc Zyngier wrote: > On Wed, 20 Apr 2016 07:08:39 -0700 > Ashok Kumar <ashoks@xxxxxxxxxxxx> wrote: > > > For guests with NUMA configuration, Node ID needs to > > be recorded in the respective affinity byte of MPIDR_EL1. > > As others have said before, the mapping between the NUMA hierarchy and > MPIDR_EL1 are completely arbitrary, and only the firmware description > can help the kernel in interpreting the affinity levels. > > If you want any patch like this one to be considered, I'd like to see > the corresponding userspace that: > > - programs the affinity into the vcpus, I have a start on this for QEMU that I can dust off and send as an RFC soon. > - pins the vcpus to specific physical CPUs, This wouldn't be part of the userspace directly interacting with KVM, but rather a higher level (even higher than libvirt, e.g. openstack/ovirt). I also don't think we should need to worry about which/how the phyiscal cpus get chosen. Let's assume that entity knows how to best map the guest's virtual topology to a physical one. > - exposes the corresponding firmware description (either DT or ACPI) to > the kernel. The QEMU patches I've started on already generate the DT (the cpu-map node). I started looking into how to do it for ACPI too, but there were some questions about whether or not the topology description tables added to the 6.1 spec were sufficient. I can send the DT part soon, and continue to look into the ACPI part later though. Thanks, drew _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
