Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750722AbWHVTnp (ORCPT ); Tue, 22 Aug 2006 15:43:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750758AbWHVTnp (ORCPT ); Tue, 22 Aug 2006 15:43:45 -0400 Received: from mailout1.vmware.com ([65.113.40.130]:31650 "EHLO mailout1.vmware.com") by vger.kernel.org with ESMTP id S1750722AbWHVTno (ORCPT ); Tue, 22 Aug 2006 15:43:44 -0400 Message-ID: <44EB5E6F.5090001@vmware.com> Date: Tue, 22 Aug 2006 12:43:43 -0700 From: Zachary Amsden User-Agent: Thunderbird 1.5.0.5 (X11/20060719) MIME-Version: 1.0 To: Arjan van de Ven Cc: Alan Cox , Andi Kleen , virtualization@lists.osdl.org, Jeremy Fitzhardinge , Andrew Morton , Chris Wright , Linux Kernel Mailing List Subject: Re: [PATCH] paravirt.h References: <1155202505.18420.5.camel@localhost.localdomain> <44DB7596.6010503@goop.org> <1156254965.27114.17.camel@localhost.localdomain> <200608221544.26989.ak@muc.de> <44EB3BF0.3040805@vmware.com> <1156271386.2976.102.camel@laptopd505.fenrus.org> <1156275004.27114.34.camel@localhost.localdomain> <44EB584A.5070505@vmware.com> <44EB5A76.9060402@vmware.com> <1156274983.2976.111.camel@laptopd505.fenrus.org> In-Reply-To: <1156274983.2976.111.camel@laptopd505.fenrus.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1103 Lines: 26 Arjan van de Ven wrote: >> That is a really nasty problem. You need a synchronization primitive >> which guarantees a flat stack, so you can't do it in the interrupt >> handler as I have tried to do. I'll bang my head on it awhile. In the >> meantime, were there ever any solutions to the syscall patching problem >> that might lend me a clue as to what to do (or not to do, or impossible?). >> > > yes we just disallowed it :) > Ok, I just took a cold shower. Actually, this problem is much easier to solve for paravirt-ops, since they are short lived operations and don't block. For syscall, it is much, much harder, since you have syscalls that can block forever, so you can't guarantee you'll exit all instances of the syscall you want to patch. I think the paravirt-ops one is doable with exports already provided by Linux. Zach - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/