From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932164AbbDANBM (ORCPT ); Wed, 1 Apr 2015 09:01:12 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34733 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932142AbbDANBH (ORCPT ); Wed, 1 Apr 2015 09:01:07 -0400 Date: Wed, 1 Apr 2015 15:00:58 +0200 From: "Michael S. Tsirkin" To: Cornelia Huck Cc: Rusty Russell , linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: Re: [PATCH v2 1/6] virtio_balloon: transitional interface Message-ID: <20150401132526-mutt-send-email-mst@redhat.com> References: <1427831230-28044-1-git-send-email-mst@redhat.com> <1427831230-28044-2-git-send-email-mst@redhat.com> <87mw2sy0fo.fsf@rustcorp.com.au> <20150401094236-mutt-send-email-mst@redhat.com> <87h9t06w3h.fsf@rustcorp.com.au> <20150401113300-mutt-send-email-mst@redhat.com> <20150401122244.5a033ff5.cornelia.huck@de.ibm.com> <20150401122413-mutt-send-email-mst@redhat.com> <20150401125748.2ec33b97.cornelia.huck@de.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150401125748.2ec33b97.cornelia.huck@de.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 01, 2015 at 12:57:48PM +0200, Cornelia Huck wrote: > On Wed, 1 Apr 2015 12:28:30 +0200 > "Michael S. Tsirkin" wrote: > > > On Wed, Apr 01, 2015 at 12:22:44PM +0200, Cornelia Huck wrote: > > > On Wed, 1 Apr 2015 11:43:46 +0200 > > > "Michael S. Tsirkin" wrote: > > > > > > > On Wed, Apr 01, 2015 at 07:53:14PM +1030, Rusty Russell wrote: > > > > > "Michael S. Tsirkin" writes: > > > > > > On Wed, Apr 01, 2015 at 02:17:23PM +1030, Rusty Russell wrote: > > > > > >> I would leave the device *exactly* as is, ugly structure packing and > > > > > >> all. > > > > > > > > > > > > But why? It's going to be used for years, might as well make it clean? > > > > > > > > > > Because the only spec which currently exists says to do that. > > > > > > > > OK but the only spec which currently exists also says it's a legacy only > > > > device, so driver must not set VERSION_1. So surely, we can make minor > > > > changes when VERSION_1 is set, like we did for other devices. > > > > > > But we don't plan to replace the other devices, so it makes sense to do > > > some changes for 1.0. > > > > I'm not sure what the above says. Do you agree with > > making minor changes in device behaviour? > > The other way around. > > > Also to be clear, I think this is 1.1 material. > > Btw, I'd really like to see your proposed spec updates. Just sent. > > > > > > > > > > Let me post the latest patches I'm working on, > > > > see what you think then. > > > > > > > > > We do > > > > > need a new virtio memballoon spec, but it'll look nothing like this > > > > > anyway. > > > > > > > > > > Cheers, > > > > > Rusty. > > > > > > > > I think it's going to have significantly different semantics, too, > > > > so not much value in making that one work with current > > > > drivers, right? > > > > > > > > > > So why not just keep virtio-balloon as-is and just specify endianness > > > etc. for 1.0? Keeps the old drivers going without hacks, > > > and we can > > > start with a fresh driver for the new virtio-balloon. > > > > Well it doesn't really, we need cpu_to_virtio in a bunch of > > places anyway. > > Of course, but what about keeping changes minimal? > > > > So I kind of prefer making it clean, even just to avoid setting a bad > > example for other devices. > > > > Let me post the new patch where it's all fixed in a cleaner way, and > > everyone can discuss whether it's too much work. > >