From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gleb Natapov Subject: Re: [PATCH] KVM: VMX: Update instruction length on intercepted BP Date: Tue, 16 Feb 2010 13:20:21 +0200 Message-ID: <20100216112021.GJ2995@redhat.com> References: <20100214103445.GH2511@redhat.com> <4B77D4DE.3030602@web.de> <20100214111544.GJ2511@redhat.com> <4B77E0E2.7030704@web.de> <20100214144501.GN2511@redhat.com> <4B7826D3.7080201@web.de> <20100214165319.GA19246@redhat.com> <4B782D97.9030304@web.de> <20100214172613.GB19246@redhat.com> <4B7837A3.4040607@web.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Avi Kivity , Marcelo Tosatti , kvm To: Jan Kiszka Return-path: Received: from mx1.redhat.com ([209.132.183.28]:10878 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753998Ab0BPLUY (ORCPT ); Tue, 16 Feb 2010 06:20:24 -0500 Content-Disposition: inline In-Reply-To: <4B7837A3.4040607@web.de> Sender: kvm-owner@vger.kernel.org List-ID: On Sun, Feb 14, 2010 at 06:49:23PM +0100, Jan Kiszka wrote: > > Lets check if SVM works. I can do that if you tell me how. > > - Fire up some Linux guest with gdb installed > - Attach gdb to gdbstub of the VM I get "Remote 'g' packet reply is too long". My guest and host are 64 bit. > - Set a soft breakpoint in guest kernel, ideally where it does not > immediately trigger, e.g. on sys_reboot (use grep sys_reboot > /proc/kallsyms if you don't have symbols for the guest kernel) > - Start gdb /bin/true in the guest > - run > > As gdb sets some automatic breakpoints, this already exercises the > reinjection of #BP. > > > My concern is > > that if SVM doesn't work we will write another way to handle this > > situation that will work on SVM and VMX and then we will have code in > > VMX that is not needed, but we have to support it. > > I understand your concerns, but I do not share them ATM. I bet we will > need some workaround for older SVM, but it will be some SVM-only thing. > Anyway, we can wait with this patch a few days until we know more. > > Jan > -- Gleb.