On 13/05/20 14:52, Vivek Goyal wrote: >>> Also, type of event should not necessarily be tied to delivery method. >>> For example if we end up introducing say, "KVM_PV_REASON_PAGE_ERROR", then >>> I would think that event can be injected both using exception (#PF or #VE) >>> as well as interrupt (depending on state of system). >> Why bother preserving backwards compatibility? > New machanism does not have to support old guests but old mechanism > should probably continue to work and deprecated slowly, IMHO. Otherwise > guests which were receiving async page faults will suddenly stop getting > it over hypervisor upgrade and possibly see drop in performance. Unfortunately, the old mechanism was broken enough, and in enough different ways, that it's better to just drop it. The new one using #VE is not coming very soon (we need to emulate it for <Broadwell and AMD processors, so it's not entirely trivial) so we are going to keep "page not ready" delivery using #PF for some time or even forever. However, page ready notification as #PF is going away for good. That said, type1/type2 is quite bad. :) Let's change that to page not present / page ready. Thanks, Paolo
