Linux's KVM Virtualization Preparing For Intel Advanced Performance Extensions (APX)
Intel's Advanced Performance Extensions (APX) debuting with Nova Lake and Diamond Rapids is ready with Linux 6.16+ and recent open-source compilers. One piece of the support puzzle still coming together though that will be especially important for Xeon Diamond Rapids is the KVM virtualization support. New patches there were posted this week.
Sean Christopherson of Google posted a set of seven new patches this week in preparing Linux's Kernel-based Virtual Machine (KVM) for supporting Intel APX. A particular focus with the patches is on preparing Linux KVM VMs for the additional general purpose registers (GPRs) available with APX CPUs. This is on top of other KVM APX code from last year.
Sean explained with the patches:
Fortunately there still is time to get this Linux KVM support for APX all in order before Diamond Rapids server processors end up shipping.
Sean Christopherson of Google posted a set of seven new patches this week in preparing Linux's Kernel-based Virtual Machine (KVM) for supporting Intel APX. A particular focus with the patches is on preparing Linux KVM VMs for the additional general purpose registers (GPRs) available with APX CPUs. This is on top of other KVM APX code from last year.
Sean explained with the patches:
"Clean up KVM's register tracking and storage in preparation for landing APX, which expands the maximum number of GPRs from 16 to 32.
This is kinda sorta an RFC, as there are some very opinionated changes. I.e. if you dislike something, please speak up.
My thought is to treat R16-R31 as much like other GPRs as possible (though maybe we don't need to expand regs[] as sketched out in the last patch?)."
Fortunately there still is time to get this Linux KVM support for APX all in order before Diamond Rapids server processors end up shipping.