From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1MUKch-0002YE-K2 for qemu-devel@nongnu.org; Fri, 24 Jul 2009 09:15:43 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1MUKcc-0002Ww-4l for qemu-devel@nongnu.org; Fri, 24 Jul 2009 09:15:42 -0400 Received: from [199.232.76.173] (port=59322 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MUKcc-0002Wt-22 for qemu-devel@nongnu.org; Fri, 24 Jul 2009 09:15:38 -0400 Received: from mx20.gnu.org ([199.232.41.8]:59360) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1MUKcb-0000Ny-Pl for qemu-devel@nongnu.org; Fri, 24 Jul 2009 09:15:37 -0400 Received: from david.siemens.de ([192.35.17.14]) by mx20.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1MUKca-0006aT-QA for qemu-devel@nongnu.org; Fri, 24 Jul 2009 09:15:37 -0400 Message-ID: <4A69B3F4.9040204@siemens.com> Date: Fri, 24 Jul 2009 15:15:32 +0200 From: Jan Kiszka MIME-Version: 1.0 References: <1248384704-47824-1-git-send-email-agraf@suse.de> <1248384704-47824-2-git-send-email-agraf@suse.de> <1248384704-47824-3-git-send-email-agraf@suse.de> <4A699405.9010703@siemens.com> <9F9055AA-6842-4938-AE7E-62A515E01025@suse.de> <4A69985B.70308@siemens.com> <75AD4198-F91C-45D0-89E5-E9F27FF2B90A@suse.de> <4A69A044.6080502@siemens.com> <4A69AFD7.3050703@siemens.com> <256A1CCF-47D1-4727-A4BA-E34B72F3408E@suse.de> In-Reply-To: <256A1CCF-47D1-4727-A4BA-E34B72F3408E@suse.de> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] Re: [PATCH 2/3] Assume PPC64 host on PPC32 KVM List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alexander Graf Cc: qemu-devel@nongnu.org Alexander Graf wrote: > > On 24.07.2009, at 14:57, Jan Kiszka wrote: > >> Alexander Graf wrote: >>> >>> On 24.07.2009, at 13:51, Jan Kiszka wrote: >>> > > [...] > >>> There are no 32-bit PowerPC KVM kernels that can do dirty logging. >> >> By design or by lack of implementation? > > Lack of implementation. > >> And what if some other arch with support for both pops up? #ifdef >> HOST_PPC is no long-term solutions. And I see no need to install a >> temporary workaround given the currently existing kernel support. > > I'd like to have the qemu bits sorted out while polishing the kvm parts, > so when kvm support shows up mainline there's a working userspace part. I understand. But the risk is that what you submit to qemu and kvm may receive different reviews and finally look different. So for stuff which concerns not yet existing (or fully implemented) interfaces, the other way around is better. Specifically if there is a "risk" that it makes into a qemu release before the corresponding kernel bits are official. > >>>> In any case, I suggest to pin down the word size and use it for all >>>> hosts. >>> >>> That would break backwards compatibility. >> >> x86 and ia64 are little endian for which is doesn't matter, PowerPC and >> s390 don't support dirty logging so far. Or what would break? > > Oh you mean just always use u32* and be done with it? > Or u64* as you suggested. It doesn't matter for existing support, and future support should simply use that type even on 32-bit hosts. > Sounds appealing... > > Alex > Jan -- Siemens AG, Corporate Technology, CT SE 2 Corporate Competence Center Embedded Linux