New x86/x86_64 KVM Patches Would Help Reduce Excess TLB Flushing

A set of more than two dozen patches by Google engineer Sean Christopherson overhauls KVM's x86/x86_64 TDP MMU zapping and flushing code.

The focus of the work is to help reduce the number of TLB flushes while the code is cleaned up in the process too.

The exciting element is the significant impact it had on cutting down the number of TLB flushes, which can help with performance. Christopherson noted, "For booting an 8 vCPU, remote_tlb_flush (requests) goes from roughly
180 (600) to 130 (215)."

This set of patches to the KVM x86/mmu code is out for review on the kernel mailing list.