Re: [Qemu-devel] [PATCH 6/6] [S390] Add firmware code

From: Aurelien Jarno <aurelien@aurel32.net>
To: Alexander Graf <agraf@suse.de>
Cc: waldi@debian.org, Carsten Otte <carsteno@de.ibm.com>,
	qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 6/6] [S390] Add firmware code
Date: Sat, 10 Apr 2010 17:03:03 +0200	[thread overview]
Message-ID: <20100410150302.GC23683@volta.aurel32.net> (raw)
In-Reply-To: <1D45AD54-36AC-4514-8D41-8A67198975F6@suse.de>

On Sat, Apr 10, 2010 at 11:22:37AM +0200, Alexander Graf wrote:
> 
> On 10.04.2010, at 02:00, Aurelien Jarno wrote:
> 
> > On Sat, Apr 10, 2010 at 01:29:55AM +0200, Alexander Graf wrote:
> >> 
> >> On 09.04.2010, at 22:17, Aurelien Jarno wrote:
> >> 
> >>> On Thu, Apr 01, 2010 at 06:42:41PM +0200, Alexander Graf wrote:
> >>>> This patch adds a firmware blob to the S390 target. The blob is a simple
> >>>> implementation of a virtio client that tries to read the second stage
> >>>> bootloader from sectors described as of offset 0x20 in the MBR.
> >>>> 
> >>>> In combination with an updated zipl this allows for booting from virtio
> >>>> block devices. This firmware is built from the same sources as the second
> >>>> stage bootloader. You can find the zipl patch to build both here:
> >>>> 
> >>>> http://alex.csgraf.de/qemu/0001-Zipl-VirtIO-bootloader-code.patch
> >>> 
> >>> I am not fully comfortable introducing a binary firmware based on a
> >>> patch posted on a website. I see two options:
> >>> - Get your patch merged into ZIPL, so that we can build the firmware
> >>> directly from the ZIPL sources
> >> 
> >> IBM wants to keep the copyright on the zipl sources, so this one's out.
> > 
> > You can't transfer the copyright, as it is done for example for GNU
> > projects?
> 
> I don't think so. Apart from it being illegal in Germany (you can't transfer full copyrights) I'm not sure that'd really help.
> 
> Another idea:
> 
> How about I set up a git tree on repo.or.cz and put it there? That git tree would contain all my changes, be a single public source and I'd try to pull all 'upstream' changes back in?

Also looks a good idea.

> >>> 
> >>> Also do you really want to make the firmware mandatory? What about a
> >>> warning and falling back to the direct kernel boot instead (if provided), 
> >>> as it is already now. Some other machines are doing that.
> >> 
> >> Yes, I do. It doesn't hurt to have it loaded and on -kernel we can just set the PSW differently, thus making the guest jump directly into the kernel. So the firmware is loaded and completely ignored. That's btw what happens with this patch already. -kernel overrides the firmware.
> >> 
> > 
> > That means people needs to have the firmware installed even if they
> > don't need it.
> 
> I don't see a problem there. It's less than 4k. Plus it's mandatory for x86 and ppc too, so why make it different?
> 

It's mandatory for x86 and ppc as the bootloader is actually doing the
jump to the kernel (for ppc it even provide some services to the kernel).

The main problem I see is for distributions that want to rebuild the
firmwares from sources. Also making it optional is just a few lines
more.

-- 
Aurelien Jarno                          GPG: 1024D/F1BCDB73
aurelien@aurel32.net                 http://www.aurel32.net