From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38004) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bFb53-0005nX-QO for qemu-devel@nongnu.org; Wed, 22 Jun 2016 01:52:10 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bFb50-0001uT-Py for qemu-devel@nongnu.org; Wed, 22 Jun 2016 01:52:04 -0400 Received: from mx1.redhat.com ([209.132.183.28]:41938) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bFb50-0001uP-Jh for qemu-devel@nongnu.org; Wed, 22 Jun 2016 01:52:02 -0400 References: <1466445226-19808-1-git-send-email-david.vrabel@citrix.com> <57689C0B.2060108@redhat.com> <57690AAA.1060003@citrix.com> From: Jason Wang Message-ID: <576A277E.6010209@redhat.com> Date: Wed, 22 Jun 2016 13:51:58 +0800 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCHv2] rtl8139: save/load RxMulOk counter (again) List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini , David Vrabel , qemu-devel@nongnu.org On 2016=E5=B9=B406=E6=9C=8821=E6=97=A5 18:11, Paolo Bonzini wrote: > On 21/06/2016 11:36, David Vrabel wrote: >> >On 21/06/16 08:35, Paolo Bonzini wrote: >>> >> >>> >> >>> >>On 21/06/2016 03:44, Jason Wang wrote: >>>> >>> >>>> >>> >>>> >>>On 2016=E5=B9=B406=E6=9C=8821=E6=97=A5 01:53, David Vrabel wrote: >>>>> >>>>Commit 9d29cdeaaca3a0383af764000b71492c4fc67c6e (rtl8139: port >>>>> >>>>TallyCounters to vmstate) introduced in incompatibility in the = v4 >>>>> >>>>format as it omitted the RxOkMul counter. >>>>> >>>> >>>>> >>>>There are presumably no users that were impacted by the v4 to v= 4' >>>>> >>>>breakage, so increase the save version to 5 and re-add the fiel= d, >>>>> >>>>keeping backward compatibility with v4'. >>>>> >>>> >>>>> >>>>We can't have a field conditional on the section version in >>>>> >>>>vmstate_tally_counters since this version checked would not be = the >>>>> >>>>section version (but the version defined in this structure). S= o, move >>>>> >>>>all the fields into the main state structure. >>>>> >>>> >>>>> >>>>Signed-off-by: David Vrabel >>>> >>> >>>> >>>Migration to old version is important for the user and this patch= seems >>>> >>>to break this. How about something like: >>>> >>> >>>> >>>- introduce a subsection for RXOKMul >>>> >>>- only migrate it for new version (e.g >=3D 2.7) >> > >> >I don't see how this can work with snapshots where the QEMU version t= hat >> >is going to restore the snapshot is not known in advance. > By "new version" he meant the versioned machine types, e.g. > pc-i440fx-2.6 and older wouldn't migrate it. > >>> >>Introducing a subsection is not really necessary if the value is go= ing >>> >>to be migrated always, and upstream generally does not have "migrat= e it >>> >>only in some version" checks. This is left for downstreams to impl= ement >>> >>if they care. We just don't have the manpower to ensure that migra= tion >>> >>to older versions works between all releases of QEMU. >> > >> >So is this patch acceptable as is? > I think it is. > > Paolo Applied to -net. Thanks