On Fri, Aug 25, 2023 at 04:15:41PM -0700, Sean Christopherson wrote: > On Fri, Jul 14, 2023, Yan Zhao wrote: > > Split a single gfn zap range (specifially range [0, ~0UL)) to smaller > > ranges according to current memslot layout when guest MTRRs are honored. > > > > Though vCPUs have been serialized to perform kvm_zap_gfn_range() for MTRRs > > updates and CR0.CD toggles, contention caused rescheduling cost is still > > huge when there're concurrent page fault holding mmu_lock for read. > > Unless the pre-check doesn't work for some reason, I definitely want to avoid > this patch. This is a lot of complexity that, IIUC, is just working around a > problem elsewhere in KVM. > I think so too.
