From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1767640AbXCIXT1 (ORCPT ); Fri, 9 Mar 2007 18:19:27 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1767642AbXCIXT1 (ORCPT ); Fri, 9 Mar 2007 18:19:27 -0500 Received: from mx1.redhat.com ([66.187.233.31]:45094 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1767640AbXCIXT0 (ORCPT ); Fri, 9 Mar 2007 18:19:26 -0500 Message-ID: <45F1EA32.8080108@redhat.com> Date: Fri, 09 Mar 2007 18:13:54 -0500 From: Rik van Riel Organization: Red Hat, Inc User-Agent: Thunderbird 1.5.0.7 (X11/20061008) MIME-Version: 1.0 To: Ingo Molnar CC: Chris Wright , Linus Torvalds , Jeremy Fitzhardinge , Zachary Amsden , Thomas Gleixner , john stultz , akpm@linux-foundation.org, LKML , Rusty Russell , Andi Kleen , Alan Cox Subject: Re: ABI coupling to hypervisors via CONFIG_PARAVIRT References: <20070309180230.GA17988@elte.hu> <20070309192420.GA27747@elte.hu> <20070309210430.GA14905@elte.hu> <20070309212714.GU10574@sequoia.sous-sol.org> <20070309214704.GA20988@elte.hu> <20070309221046.GV10574@sequoia.sous-sol.org> <20070309222435.GB24341@elte.hu> In-Reply-To: <20070309222435.GB24341@elte.hu> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Ingo Molnar wrote: > ok, sure, how about the one i mentioned: long-term i'd like to have a > paravirt model where the guest does not store /any/ page tables - all > paging is managed by the hypervisor. The guest has a vma tree, but > otherwise it does not process pagefaults, has no concept of a pte (if in > paravirt mode), has no concept of kernel page tables either: there are > hypercalls to allocate/free guest-kernel memory, etc. This needs some > (serious) MM surgery but it's doable and it's interesting as well. How > would you map this to the VMI backend? Ugh! In a situation like that, how does the guest handle pageouts? What about the dirty and accessed bits? I'm guessing VMI would deal with this kind of abstraction in exactly the same way we do the "native hardware" layer behind paravirt_ops. Ie. this example is a red herring. -- Politics is the struggle between those who want to make their country the best in the world, and those who believe it already is. Each group calls the other unpatriotic.