From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57545) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VBiyV-0002IU-PG for qemu-devel@nongnu.org; Tue, 20 Aug 2013 06:15:49 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VBiyP-0006Qd-F1 for qemu-devel@nongnu.org; Tue, 20 Aug 2013 06:15:43 -0400 Message-ID: <52134195.6040900@redhat.com> Date: Tue, 20 Aug 2013 12:14:45 +0200 From: Paolo Bonzini MIME-Version: 1.0 References: <1375862885-12132-1-git-send-email-aik@ozlabs.ru> <520DF5B5.4050805@ozlabs.ru> <5210E6C2.1070208@redhat.com> <5211C99B.4070904@ozlabs.ru> <0E406847-EB38-4E35-9447-657BFF7FF70A@suse.de> <5211DAD3.1050602@ozlabs.ru> <5211E9AB.7050700@redhat.com> <5212C81B.2090403@ozlabs.ru> <52132B28.9030803@redhat.com> <52132D9F.8070607@ozlabs.ru> <52133232.7010809@redhat.com> <1376989997.25016.131.camel@pasglop> <521333CB.1080407@redhat.com> <1376990419.25016.138.camel@pasglop> <5213353E.6080004@redhat.com> <1376990796.25016.140.camel@pasglop> In-Reply-To: <1376990796.25016.140.camel@pasglop> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] powerpc iommu: enable multiple TCE requests List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Benjamin Herrenschmidt Cc: Alexey Kardashevskiy , Alexander Graf , "qemu-devel@nongnu.org" , "qemu-ppc@nongnu.org" , Paul Mackerras , David Gibson Il 20/08/2013 11:26, Benjamin Herrenschmidt ha scritto: > On Tue, 2013-08-20 at 11:22 +0200, Paolo Bonzini wrote: >> >> Uhm... I thought Alex and I were the one who proposed the simple things. >> You _will_ need to do the complicated stuff sooner or later, but it's >> probably early enough now to ignore it. >> >> And I'm not saying this out of love for big cathedrals, but out of >> lessons we learned the hard way for x86 (where we haven't gotten >> everything right yet, either). > > I suppose if RH is going to deploy 3.10 and we aren't going to backport > the multitce patches then there *might* be a case for supporting that > combo specifically... but it's going to be that bad every time we add > a new feature with a kernel counter part or start adding the gazillion > little bits of PAPR that we are still missing ? Yes. :( Unless you consider pSeries KVM not mature enough to provide a guest ABI (basically supporting live migration only between identical kernels and QEMUs). It would make some sense, for example (mutatis mutandis) Red Hat has a kernel ABI for the "regular" RHEL kernel, but not for the "real-time" RHEL kernel. Paolo