From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41212) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XN81r-00030z-KW for qemu-devel@nongnu.org; Thu, 28 Aug 2014 18:18:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XN81l-00082J-Dd for qemu-devel@nongnu.org; Thu, 28 Aug 2014 18:18:51 -0400 Message-ID: <53FFAAC4.2050408@suse.de> Date: Fri, 29 Aug 2014 00:18:44 +0200 From: Alexander Graf MIME-Version: 1.0 References: <20140825134353.2361.52046.stgit@aravindap> <20140825134516.2361.32987.stgit@aravindap> <53FF0732.6090008@suse.de> <53FF72DD.5010009@linux.vnet.ibm.com> In-Reply-To: <53FF72DD.5010009@linux.vnet.ibm.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [Qemu-ppc] [PATCH 1/5] target-ppc: Extend rtas-blob List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Aravinda Prasad Cc: benh@au1.ibm.com, aik@au1.ibm.com, qemu-devel@nongnu.org, qemu-ppc@nongnu.org, paulus@samba.org On 28.08.14 20:20, Aravinda Prasad wrote: > > > On Thursday 28 August 2014 04:10 PM, Alexander Graf wrote: >> >> >> On 25.08.14 15:45, Aravinda Prasad wrote: >>> Extend rtas-blob to accommodate error log. Error log >>> structure is saved in rtas space upon a machine check >>> exception. >>> >>> Signed-off-by: Aravinda Prasad >> >> I can't say I'm a big fan of this patch. Can we somehow separate that >> NMI page from the RTAS blob? Also I'd definitely prefer if we keep >> rtas_entry == rtas_addr - if nothing else for the sake of backwards >> compatibility. >> >> So how about we lay out the structure in memory like this: >> >> [ spapr-rtas.bin ] >> [ padding to 4k boundary or whatever sPAPR requires ] >> [ 4k NMI region ] >> >> Then the only thing we'd have to really change internally is the size >> information of the rtas blob. > > Either we can have it like this or completely eliminate spapr-rtas.bin > (and spapr-rtas.S) by simply allocating required space in QEMU and then > patching the 5 instructions at rtas-entry as earlier discussed with David. > > http://lists.nongnu.org/archive/html/qemu-ppc/2014-08/msg00251.html > I strongly disagree with David. Legally there is no difference between a .bin file that contains code and an array made of instructions. And the more target code we can keep outside of QEMU the better. Alex