From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57264) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VszND-0003Q6-HP for qemu-devel@nongnu.org; Tue, 17 Dec 2013 13:28:08 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VszN8-0002WK-Lm for qemu-devel@nongnu.org; Tue, 17 Dec 2013 13:28:03 -0500 Received: from mail-pb0-f43.google.com ([209.85.160.43]:52506) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VszN8-0002W8-Fl for qemu-devel@nongnu.org; Tue, 17 Dec 2013 13:27:58 -0500 Received: by mail-pb0-f43.google.com with SMTP id rq2so7311009pbb.30 for ; Tue, 17 Dec 2013 10:27:57 -0800 (PST) MIME-Version: 1.0 In-Reply-To: References: <1387301460-28164-2-git-send-email-stefano.stabellini@eu.citrix.com> From: Peter Maydell Date: Tue, 17 Dec 2013 18:27:37 +0000 Message-ID: Content-Type: text/plain; charset=UTF-8 Subject: Re: [Qemu-devel] [PATCH 2/2] xen: build on ARM List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefano Stabellini Cc: Anthony PERARD , "xen-devel@lists.xensource.com Devel" , QEMU Developers On 17 December 2013 18:20, Stefano Stabellini wrote: > On Tue, 17 Dec 2013, Peter Maydell wrote: >> Per-host-architecture ifdef ladders are kind of nasty. What's this >> code actually trying to do ? (looks like maybe "64 bit host addresses >> vs 32 bit host addresses" ?) > > Almost. > It is trying to decide how much stuff we can map into QEMU's address > space (that is what the "Cap" is referring to). In particular consider > the case where we are running on an ARMv8 system, dom0 and QEMU are > 32-bit and the guest is 64-bit. Right, so you essentially want to know the size of a host address (that's 32 bits in a 32 bit QEMU even if the h/w is ARMv8). #if HOST_LONG_BITS == 32 [stuff for 32 bit address space] #else [stuff for 64 bit address space] #endif thanks -- PMM