From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: swapping with MMU Notifiers V2 Date: Tue, 29 Jan 2008 19:02:52 +0200 Message-ID: <479F5C3C.7070501@qumranet.com> References: <20080129145021.GJ7233@v2.random> <479F50D6.4020005@de.ibm.com> <479F532C.1020503@qumranet.com> <479F55D6.1090807@de.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, Andrea Arcangeli To: carsteno-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org Return-path: In-Reply-To: <479F55D6.1090807-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Carsten Otte wrote: > Avi Kivity wrote: >> Every arch except s390 needs it. An ugly #ifndef = >> CONFIG_KVM_HARDWARE_TLB_SYNC is preferred to duplicating the code. > BTW, from reading AMDs spec I don't expect NPT to need this vehicle = > for swapping either. They can just let core-vm page out guest pages = > and will receive a proper page fault in the host. J=F6rg can you confirm = > that? > No, that doesn't work: - even though npt can use the same pagetable for guest and host, that = isn't workable for kvm as npt doesn't have an offset/size thing. so kvm = uses a separate pagetable for guest and host. - npt doesn't have a dual-tagged tlb, where a host tlb invalidate also = invalidates all guest tlbs that point to the same page Try again in 25 years, maybe x86 will reach where s390 is now by that = timeframe. -- = error compiling committee.c: too many arguments to function ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/