From mboxrd@z Thu Jan 1 00:00:00 1970 From: Carsten Otte Subject: Re: swapping with MMU Notifiers V2 Date: Wed, 30 Jan 2008 16:14:48 +0100 Message-ID: <47A09468.7000208@de.ibm.com> References: <20080129145021.GJ7233@v2.random> <479F50D6.4020005@de.ibm.com> <479F532C.1020503@qumranet.com> <479F55D6.1090807@de.ibm.com> <20080129175420.GR7233@v2.random> <47A05EEF.3010701@de.ibm.com> <20080130114206.GG7233@v2.random> <47A09142.4090307@de.ibm.com> <47A09342.1040708@qumranet.com> Reply-To: carsteno-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: carsteno-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org, kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, Andrea Arcangeli To: Avi Kivity Return-path: In-Reply-To: <47A09342.1040708-atKUWr5tajBWk0Htik3J/w@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 Avi Kivity wrote: > Carsten Otte wrote: >> We have similar restrictions than you're naming here. Our guest may >> start at a (userspace-) page boundary, and has a fixed 1:1 mapping to >> userspace for a given length. We do that by just having one memory >> slot which has to start at virtual address zero in kvm. > > I thought you're using an offset to put the guest somewhere else? > Putting the guest at offset zero means that a qemu null pointer deref > causes a memory corruption instead of an abort. At a page boundary in userspace (non-zero), that matches zero in guest physical. 1:1+n. Sorry for causing the confusion, my explanation was diffuse. >> I have way to few knowledge about x86, but to me both the native page >> table layout and the nested one look very similar. I believe AMD has >> done a pretty good job designing that. > > The page table formats are identical. Looks like Andrea should start hacking then ;-). ------------------------------------------------------------------------- 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/