From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:46345) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QYHad-0004wT-Rj for qemu-devel@nongnu.org; Sun, 19 Jun 2011 08:59:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QYHac-0003Xe-JO for qemu-devel@nongnu.org; Sun, 19 Jun 2011 08:58:59 -0400 Received: from mx1.redhat.com ([209.132.183.28]:5553) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QYHac-0003XV-8e for qemu-devel@nongnu.org; Sun, 19 Jun 2011 08:58:58 -0400 Message-ID: <4DFDF28D.3030206@redhat.com> Date: Sun, 19 Jun 2011 15:58:53 +0300 From: Avi Kivity MIME-Version: 1.0 References: <4DF33413.9070605@web.de> <4DF8B0E6.1080806@siemens.com> In-Reply-To: <4DF8B0E6.1080806@siemens.com> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v2][uq/master] kvm: x86: Save/restore FPU OP, IP and DP List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jan Kiszka Cc: Marcelo Tosatti , qemu-devel , kvm On 06/15/2011 04:17 PM, Jan Kiszka wrote: > These FPU states are properly maintained by KVM but not yet by TCG. So > far we unconditionally set them to 0 in the guest which may cause > state corruptions, though not with modern guests. > > To avoid breaking backward migration, use a conditional subsection that > is only written if any of the three fields is non-zero. The guest's > FNINIT clears them frequently, and cleared IA32_MISC_ENABLE MSR[2] > reduces the probability of non-zero values further so that this > subsection is not expected to restrict migration in any common scenario. Thanks, applied to uq/master. A test migration showed that the subsection in fact did not show up. -- error compiling committee.c: too many arguments to function