From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43789) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Y0VnN-0006fc-Dl for qemu-devel@nongnu.org; Mon, 15 Dec 2014 08:34:47 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Y0VnH-0004xL-5O for qemu-devel@nongnu.org; Mon, 15 Dec 2014 08:34:41 -0500 Message-ID: <548EE361.605@redhat.com> Date: Mon, 15 Dec 2014 14:34:25 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: <1418388243-1886-1-git-send-email-pbonzini@redhat.com> <1418388243-1886-2-git-send-email-pbonzini@redhat.com> <20141215104620.GB5502@work-vm> <548ECB56.6020901@redhat.com> <20141215133030.GD5502@work-vm> In-Reply-To: <20141215133030.GD5502@work-vm> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v3 1/4] serial: reset thri_pending on IER writes with THRI=0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Dr. David Alan Gilbert" Cc: imammedo@redhat.com, batuzovk@ispras.ru, andrey@xdel.ru, qemu-stable@nongnu.org, qemu-devel@nongnu.org On 15/12/2014 14:30, Dr. David Alan Gilbert wrote: > Anyone who really cares about backwards migration compatibility would > probably have to guard the subsection with the machine-type to avoid > (e) ever happening (the heuristic from (c) might be useful to add). Right. > although if you do have to recut it, please clarify the text that says > 'and is enough to fix migration.' since it doesn't quite. Ok, I'll clarify this, specifying which case remains broken by design. > (This is an interesting example where with a migration format that allowed > 'optional' subsections you wouldn't break backwards migration if the > reader could ignore a section marked as such that it didn't recognise). Right, the question is whether you really want to do this. :) Paolo