From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomasz Chmielewski Subject: Re: AMD-Intel guest migration and CPUs without NX Date: Tue, 24 Mar 2009 14:38:31 +0100 Message-ID: <49C8E257.5020903@wpkg.org> References: <49C8BA8F.8000008@wpkg.org> <49C8D4A4.2000606@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: "kvm@vger.kernel.org" To: Avi Kivity Return-path: Received: from mx03.syneticon.net ([78.111.66.105]:37866 "EHLO mx03.syneticon.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753444AbZCXNis (ORCPT ); Tue, 24 Mar 2009 09:38:48 -0400 In-Reply-To: <49C8D4A4.2000606@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: Avi Kivity schrieb: >> So the above says I may have some problems. > > Right, it's not safe in general. It may work if the guest doesn't use > NX. It may also work if the guest does not rely on NX working properly. Although I think my guests don't use it, you never know. Is it possible to disable NX for chosen guests? >> On the other hand, FAQ below seems to indicate that migration on 64 >> bit hosts should be fine (even when they don't support NX?), only 32 >> bit hosts may have problems: >> >> http://www.linux-kvm.org/page/FAQ >> >> Yes. There may be issues on 32-bit Intel hosts which don't support NX >> (or XD), but for 64-bit hosts back and forth migration should work >> well. Migration of 32-bit guests should work between 32-bit hosts and >> 64-bit hosts. > > Looks like that paragraph assumes that all 64-bit hosts have NX. Your > /proc/cpuinfo proves otherwise. -- Tomasz Chmielewski http://wpkg.org