From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56399) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b0BaB-0005Z9-5e for qemu-devel@nongnu.org; Tue, 10 May 2016 13:36:32 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1b0Ba7-00068q-KB for qemu-devel@nongnu.org; Tue, 10 May 2016 13:36:31 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50227) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b0Ba7-00068d-EH for qemu-devel@nongnu.org; Tue, 10 May 2016 13:36:27 -0400 Date: Tue, 10 May 2016 18:36:24 +0100 From: "Richard W.M. Jones" Message-ID: <20160510173624.GB1683@redhat.com> References: <1461600281-23048-1-git-send-email-rjones@redhat.com> <20160509132449.GF3372@stefanha-x1.localdomain> <20160509164814.GS1683@redhat.com> <5732194C.3050000@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5732194C.3050000@redhat.com> Subject: Re: [Qemu-devel] [PATCH v6] Add optionrom compatible with fw_cfg DMA version List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: Stefan Hajnoczi , qemu-devel , Marc =?iso-8859-1?Q?Mar=ED?= , Eduardo Habkost , "Michael S. Tsirkin" , Gerd Hoffmann , Stefan Hajnoczi , Laszlo Ersek , Richard Henderson On Tue, May 10, 2016 at 07:24:28PM +0200, Paolo Bonzini wrote: > > > On 09/05/2016 18:48, Richard W.M. Jones wrote: > > > > Of course we're well outside any standards here. Can we tell clang > > users to use the GCC/pre-compiled option ROMs :-? Any other ideas? I > > don't think I've missed a flag (GCC has -fno-toplevel-reorder, but > > clang 3.8 doesn't ...) > > I guess the checksumming script (scripts/signrom.py) could take care of > padding the file to a multiple of 512 bytes, and fill in the size in the > third byte. Then "_end" would not be necessary anymore and -m16 could > replace the .code16 directive. In my rather limited testing on gcc, gcc -m16 broke booting. However I've not investigated this further. I'll do so shortly. However I have a question: is there a formal standard or documentation for the option ROM format? Are we sticking to the (ancient) "BIOS Boot Specification" or is there something newer? (My copy is from 1996). Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-top is 'top' for virtual machines. Tiny program with many powerful monitoring features, net stats, disk stats, logging, etc. http://people.redhat.com/~rjones/virt-top