From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40990) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z1tam-000158-Jl for qemu-devel@nongnu.org; Mon, 08 Jun 2015 05:43:41 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Z1tai-0007pc-Hz for qemu-devel@nongnu.org; Mon, 08 Jun 2015 05:43:40 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59729) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z1tai-0007pO-CA for qemu-devel@nongnu.org; Mon, 08 Jun 2015 05:43:36 -0400 Date: Mon, 8 Jun 2015 11:43:32 +0200 From: "Michael S. Tsirkin" Message-ID: <20150608114309-mutt-send-email-mst@redhat.com> References: <20150601141054.GA11304@redhat.com> <20150601141343.GH13155@redhat.com> <20150601153237.GE2120@HEDWIG.INI.CMU.EDU> <20150601174409-mutt-send-email-mst@redhat.com> <20150601180022.GI2120@HEDWIG.INI.CMU.EDU> <20150601203126.GK2120@HEDWIG.INI.CMU.EDU> <1433229074.1637.7.camel@nilsson.home.kraxel.org> <20150605160555.GH9951@HEDWIG.INI.CMU.EDU> <1433748105.5046.6.camel@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1433748105.5046.6.camel@redhat.com> Subject: Re: [Qemu-devel] fw cfg files cross-version migration races List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gerd Hoffmann Cc: pbonzini@redhat.com, "Gabriel L. Somlo" , lersek@redhat.com, qemu-devel@nongnu.org On Mon, Jun 08, 2015 at 09:21:45AM +0200, Gerd Hoffmann wrote: > Hi, > > > > So, sorting entries (and the index assigned too) should fix this, right? > > > That looks easiest to me. > > > > Presumably, anything happening before (and after) user-provided blobs > > are inserted will continue happening in the same order everywhere. > > Which might change in the future though, in case the initialization > order changes for some reason. It's not a problem we have at the > moment, so this stuff isn't urgent. But we might face it in the future. > > > So we really only have to sort the user provided blobs, so that if > > the same *set* is provided on both ends of the migration, things would > > work out OK. > > I would simply sort everything (and do it for new machine types only, > for backward compatibility reasons). Sorting user-provided blobs only > adds complexity for no reason. > > > If a *different* set of blobs is specified on the migration origin vs. > > the migration destination, we lose by default and worrying about it is > > pointless -- did I get that right ? > > Yes. For migration to succeed you have to supply the same configuration > on both ends. That includes user-provided fw_cfg blobs of course. > > cheers, > Gerd > Do we want this for all machine types, or only for new ones? -- MST