From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42443) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W7wfc-00029W-V0 for qemu-devel@nongnu.org; Mon, 27 Jan 2014 19:36:59 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1W7wfW-0007c1-S3 for qemu-devel@nongnu.org; Mon, 27 Jan 2014 19:36:52 -0500 Message-ID: <1390869373.3872.43.camel@pasglop> From: Benjamin Herrenschmidt Date: Tue, 28 Jan 2014 11:36:13 +1100 In-Reply-To: References: <03D15FE3-2A12-4D60-8D20-07D05F3740F6@suse.de> <20140120191919.GH13432@cbox> <1390865691.3872.33.camel@pasglop> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [Qemu-ppc] KVM and variable-endianness guest CPUs List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Maydell Cc: Thomas Falcon , kvm-devel , Victor Kamensky , QEMU Developers , "qemu-ppc@nongnu.org" , "kvmarm@lists.cs.columbia.edu" , Christoffer Dall On Mon, 2014-01-27 at 23:49 +0000, Peter Maydell wrote: > > Er, what? If we make the array be guest's current order > then by definition userspace has to look at the guest's > current endianness. I agree that would be bad. Either > of the two current proposals (host kernel order; guest > CPU's native/natural/default-byte-order) avoid it, though. No, this has nothing to do with the guest endianness, and all to do about the (hopefully) byte-address invariant bus we have on the processor. Anyway, the existing crap is ABI so I suspect we have to stick with it, just maybe document it better. Ben.