From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=44498 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1P5i9z-0001LP-1d for qemu-devel@nongnu.org; Tue, 12 Oct 2010 12:57:08 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1P5i9w-0004yT-Lu for qemu-devel@nongnu.org; Tue, 12 Oct 2010 12:57:05 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59610) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1P5i9w-0004y2-FT for qemu-devel@nongnu.org; Tue, 12 Oct 2010 12:57:04 -0400 Date: Tue, 12 Oct 2010 18:56:58 +0200 From: Gleb Natapov Subject: Re: [SeaBIOS] [Qemu-devel] [RFC] Passing boot order from qemu to seabios Message-ID: <20101012165658.GE5218@redhat.com> References: <20101011101855.GA25030@redhat.com> <4CB2E7D0.1010702@redhat.com> <4CB2FDF2.1020705@redhat.com> <20101011121634.GB28008@redhat.com> <4CB36A20.5020106@codemonkey.ws> <20101011195955.GA5218@redhat.com> <4CB373DD.50307@codemonkey.ws> <4CB37E6E.8010106@zytor.com> <20101012080124.GY2397@redhat.com> <4CB48DCC.80804@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4CB48DCC.80804@zytor.com> List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "H. Peter Anvin" Cc: Kevin Wolf , seabios@seabios.org, qemu-devel@nongnu.org On Tue, Oct 12, 2010 at 09:33:16AM -0700, H. Peter Anvin wrote: > On 10/12/2010 01:01 AM, Gleb Natapov wrote: > > On Mon, Oct 11, 2010 at 02:15:26PM -0700, H. Peter Anvin wrote: > >>> I don't disagree. > >>> > >>> I think the best thing to do is to let SeaBIOS create a boot order table > >>> that contains descriptive information and then advertise that to QEMU. > >>> > >>> QEMU can then try to associate the list of bootable devices with it's > >>> own set of devices and select a preferred order that it can then give > >>> back to SeaBIOS. SeaBIOS can then present that list to the user for > >>> additional refinement. > >> > >> Really, this kind of comes down to having a data structure that anything > >> (Qemu, SeaBIOS and if needed the guest OS) can read and modify as needed. > >> > > But then QEMU and seabios will have to have shared storage they can > > both write too. And this shared storage is part of VM now so you need > > to carry it around when you move your VM elsewhere. > > > > Yes, and it's part of real hardware, too. It's usually called "the > CMOS", short for CMOS RAM. > On real hardware it is not shared between HW and bios. It is written/read only by BIOS. In qemu it is not persistent and generated for each qemu invocation. Previously it was used to pass config params from qemu to a bios (and some legacy params are still passed that way), but we moved to better interface for that (firmware config). -- Gleb.