From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: [PATCH 4/4] KVM: Rework of guest debug state writing Date: Thu, 04 Feb 2010 16:04:06 +0100 Message-ID: <4B6AE1E6.9040805@siemens.com> References: <372238c800e0d57815f472502fdf78e53463bbb6.1265232579.git.jan.kiszka@siemens.com> <20100203234929.GA11012@amt.cnet> <4B6A15EE.4050501@web.de> <20100204130038.GA15671@amt.cnet> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Anthony Liguori , qemu-devel@nongnu.org, Avi Kivity , kvm@vger.kernel.org To: Marcelo Tosatti Return-path: Received: from david.siemens.de ([192.35.17.14]:24292 "EHLO david.siemens.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932271Ab0BDPEf (ORCPT ); Thu, 4 Feb 2010 10:04:35 -0500 In-Reply-To: <20100204130038.GA15671@amt.cnet> Sender: kvm-owner@vger.kernel.org List-ID: Marcelo Tosatti wrote: > On Thu, Feb 04, 2010 at 01:33:50AM +0100, Jan Kiszka wrote: >> Marcelo Tosatti wrote: >>> On Wed, Feb 03, 2010 at 10:29:45PM +0100, Jan Kiszka wrote: >>>> So far we synchronized any dirty VCPU state back into the kernel before >>>> updating the guest debug state. This was a tribute to a deficit in x86 >>>> kernels before 2.6.33. But as this is an arch-dependent issue, it is >>>> better handle in the x86 part of KVM and remove the writeback point for >>>> generic code. >>> Jan, >>> >>> This patch breaks migration. >> Can you elaborate what you did? I can't reproduce, and I do not see any >> conceptual issue (given that guest debugging conflicts with migration >> anyway). > > kvm-autotest fails (migration only, install is ok, both Linux and Win > guests). Not sure why, perhaps the unconditional KVM_SET_GUEST_DEBUG > corrupts state somehow? > > Tested with io thread enabled. That's this default-off thing, so... OK, confirmed, investigating. Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux