From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50421) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YgB8Z-0001YR-Ez for qemu-devel@nongnu.org; Thu, 09 Apr 2015 08:00:53 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YgB8T-0004QM-G3 for qemu-devel@nongnu.org; Thu, 09 Apr 2015 08:00:45 -0400 Received: from mx1.redhat.com ([209.132.183.28]:42703) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YgB8Q-0004Ns-Q7 for qemu-devel@nongnu.org; Thu, 09 Apr 2015 08:00:39 -0400 Message-ID: <552669DF.40705@redhat.com> Date: Thu, 09 Apr 2015 14:00:31 +0200 From: Paolo Bonzini MIME-Version: 1.0 References: <1428437400-8474-1-git-send-email-peter.maydell@linaro.org> <1428437400-8474-8-git-send-email-peter.maydell@linaro.org> <55250AFD.3060203@redhat.com> In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 07/14] exec.c: Add new address_space_ld*/st* functions List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Maydell Cc: Peter Crosthwaite , Patch Tracking , QEMU Developers , Greg Bellows , "Edgar E. Iglesias" , =?UTF-8?B?QWxleCBCZW5uw6ll?= , Richard Henderson On 09/04/2015 13:49, Peter Maydell wrote: >> > I think we do not want to expose these at all (or at least, all users >> > should really be CPUs and hence use *_phys functions). >> > >> > S390 is always big-endian, and watch_mem_read/write can use the same >> > buffer trick as subpages (and in fact should probably use memattrs as well). >> > >> > So, please at least add a comment that these functions are deprecated, >> > and check if watch_mem_read/write should be handled like subpages. > I looked at the subpages code, and it seems to me that it's the > other way around -- the subpages code should use these new functions. > At the moment the subpage handlers use address_space_read/write > to pull the data into a buffer, and then use the ldl_p/stl_p functions > to do "read data from target-CPU order buffer into host variable". > It would be better for them to just directly be able to say "do > a ld/st in target-CPU order into this host variable", which is > the purpose of these new functions. Indirecting via a buffer seems > like an ugly workaround for not having the direct operation. Using them in subpage code is fine, but then the subpage code is in exec.c and can use the _internal version directly (and pass DEVICE_NATIVE_ENDIAN). Still, usage of these outside exec.c is probably suspicious. It's at least worth pulling these in cpu-all.h; the whole contents of cpu-common.h look like a sundry of functions that either are deprecated or should be declared elsewhere. Paolo