From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41615) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VEnCv-0004mK-Me for qemu-devel@nongnu.org; Wed, 28 Aug 2013 17:23:26 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VEnCn-0004XH-9P for qemu-devel@nongnu.org; Wed, 28 Aug 2013 17:23:17 -0400 Received: from mail-gh0-x22a.google.com ([2607:f8b0:4002:c05::22a]:46535) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VEnCn-0004T6-5T for qemu-devel@nongnu.org; Wed, 28 Aug 2013 17:23:09 -0400 Received: by mail-gh0-f170.google.com with SMTP id z10so1724698ghb.29 for ; Wed, 28 Aug 2013 14:23:08 -0700 (PDT) Sender: Richard Henderson Message-ID: <521E6A36.8050602@twiddle.net> Date: Wed, 28 Aug 2013 14:23:02 -0700 From: Richard Henderson MIME-Version: 1.0 References: <1377664796-11698-1-git-send-email-sw@weilnetz.de> <521E09DF.20102@twiddle.net> <521E16B3.3030008@twiddle.net> <20130828204239.GA11047@smtp.vpn> In-Reply-To: <20130828204239.GA11047@smtp.vpn> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC] Streamlining endian handling in TCG List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Edgar E. Iglesias" Cc: Peter Maydell , qemu-devel , Aurelien Jarno On 08/28/2013 01:42 PM, Edgar E. Iglesias wrote: > A question, some archs have an endian swap > controlled via the MMU, e.g per page selectable (some PPC, microblaze and > maybe others). AFAIK the behaviour is implementable in QEMU today but not > very efficiently. Any thoughts/ideas on this? The only thing I could imagine doing on a page-by-page basis like this is to bring this feature into the qemu page table. We'd have to hang it under the same general scheme as an IO access, where all reads/writes to the page are forced through the helper. I'd imagine that it would get handled similarly to io_mem_rom, but with different accessors. r~