From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:50034) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S2fhf-00069L-72 for qemu-devel@nongnu.org; Wed, 29 Feb 2012 04:20:13 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1S2fhY-0005xD-Lu for qemu-devel@nongnu.org; Wed, 29 Feb 2012 04:20:06 -0500 Received: from mx1.redhat.com ([209.132.183.28]:42433) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S2fhY-0005vU-D1 for qemu-devel@nongnu.org; Wed, 29 Feb 2012 04:20:00 -0500 Date: Wed, 29 Feb 2012 09:19:52 +0000 From: "Daniel P. Berrange" Message-ID: <20120229091952.GE5050@redhat.com> References: <20120227095156.GA24607@redhat.com> <4F4BA055.9010005@siemens.com> <20120229084513.GA17676@morn.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20120229084513.GA17676@morn.localdomain> Subject: Re: [Qemu-devel] Boot failure with MS-Dos 6.22 (due to bad BIOS build?) Reply-To: "Daniel P. Berrange" List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kevin O'Connor Cc: Jan Kiszka , seabios , "qemu-devel@nongnu.org" On Wed, Feb 29, 2012 at 03:45:13AM -0500, Kevin O'Connor wrote: > On Mon, Feb 27, 2012 at 04:25:09PM +0100, Jan Kiszka wrote: > > On 2012-02-27 10:51, Daniel P. Berrange wrote: > > > I'm seeing current QEMU GIT fail to boot MS-Dos 6.22 with the following > > > crash: > > > > > > # qemu-system-x86_64 -fda ~/MS-DOS\ 6.22.img -m 1 -curses > > Does the error persist when run with "-m 2"? If more memory fixes the > issue, then it is likely already fixed in upstream (commit 890d9851). > The bugs fixed in that commit are null pointer derefernce errors - in > SeaBIOS, a write to "NULL" actually alters the memory at address 0, > which can corrupt the interrupt table - these can lead to > unpredictable errors, as the timing between when an irq fires and when > the corruption occurs can vary. DOS might overwrite the irq entries > with its own settings, and thus depending on timing may cover up the > error. In short, I wouldn't assume the problem is the toolchain. The error occurs no matter what '-m XX' setting I give it. I did a git bisect across a Seabios GIT from master down torel-1.6.3.1 and could not reproduce it with any BIOS I built myself. Hence the only conclusion I could come to is that the QEMU binary was broken in some way. Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|