From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=41731 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Oe74U-0000Ll-RF for qemu-devel@nongnu.org; Wed, 28 Jul 2010 09:53:24 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1Oe74T-0000Ph-Kc for qemu-devel@nongnu.org; Wed, 28 Jul 2010 09:53:22 -0400 Received: from mx1.redhat.com ([209.132.183.28]:11583) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1Oe74T-0000PZ-87 for qemu-devel@nongnu.org; Wed, 28 Jul 2010 09:53:21 -0400 From: Juan Quintela In-Reply-To: <4C502CBC.3030005@redhat.com> (Paolo Bonzini's message of "Wed, 28 Jul 2010 15:12:28 +0200") References: <4C502CBC.3030005@redhat.com> Date: Wed, 28 Jul 2010 15:51:45 +0200 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Subject: [Qemu-devel] Re: [PATCH] vmstate: fix vmstate_subsection_load Reply-To: quintela@redhat.com List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: TeLeMan , qemu-devel Paolo Bonzini wrote: > On 07/28/2010 02:51 PM, TeLeMan wrote: > Even if they are mandatory, subsections still improve the situation > here, because they provide a clean way to "branch" off an upstream > vmstate version. At least the failure will be clear, because an > unsupported subsection is easily detected when migrating to (or > restoring with) upstream. > > Instead, for example RHEL5.5's "version 9" cpu save format will often > crash upstream version 9 with a SIGSEGV. Old kvm (pre start of merge with qemu) and qemu device versions are out of sync. You can't migrate between them at all. Basically you can't migrate from anything older than qemu-0.12. In qemu-0.12 firmware for devices got moved to pci bars and memory layout changed in such a way that it is not compatible at all. Later, Juan.