From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33898) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W6hmW-0003iT-AW for qemu-devel@nongnu.org; Fri, 24 Jan 2014 09:31:01 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1W6hmM-0008Fr-4h for qemu-devel@nongnu.org; Fri, 24 Jan 2014 09:30:52 -0500 Received: from mail-ee0-x233.google.com ([2a00:1450:4013:c00::233]:45045) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W6hmL-0008Cb-Lu for qemu-devel@nongnu.org; Fri, 24 Jan 2014 09:30:41 -0500 Received: by mail-ee0-f51.google.com with SMTP id b57so995129eek.24 for ; Fri, 24 Jan 2014 06:30:40 -0800 (PST) Sender: Paolo Bonzini Message-ID: <52E2790C.20304@redhat.com> Date: Fri, 24 Jan 2014 15:30:36 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: <1390515366-32236-1-git-send-email-wei.liu2@citrix.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH RFC 0/5] Xen: introduce Xen PV target List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Maydell , Wei Liu Cc: Anthony PERARD , "xen-devel@lists.xen.org" , QEMU Developers , Stefano Stabellini Il 23/01/2014 23:30, Peter Maydell ha scritto: >> > As promised I hacked a prototype based on Paolo's disable TCG series. >> > However I coded some stubs for TCG anyway. So this series in principle >> > should work with / without Paolo's series. > I'm afraid I still think this is a terrible idea. "Xen" isn't a CPU, and > "the binary is smaller" isn't IMHO sufficient justification for breaking > QEMU's basic structure of "target-* define target CPUs and we have > a lot of compile time constants which are specific to a CPU which > get defined there". How would you support a bigendian Xen CPU, > just to pick one example of where this falls down? (1) decide that the Xen ring buffers are little-endian even on big-endian CPUs (2) communicate the endianness of the Xen ring buffers via Xenstore, just like we do for sizeof(long), and let the guest use either endianness on any architecture. Paolo