Re: [Qemu-devel] [6064] Implement device tree support needed for Bamboo emulation

[Daniel P. Berrange]

On Tue, Dec 16, 2008 at 03:09:47PM +0000, Hollis Blanchard wrote:
> On Tue, 2008-12-16 at 12:30 +0000, Paul Brook wrote:
> > > To implement the -kernel, -initrd, and -append options, 4xx board 
> > > emulation
> > > must load the guest kernel as if firmware had loaded it. Where u-boot 
> > > would
> > > be the firmware, we must load the flat device tree into memory and set key
> > > fields such as /chosen/bootargs.
> > 
> > Then why is it optional?
> 
> As you mention below, libfdt isn't generally available yet, and since
> it's possible to make a real firmware work in this environment (in which
> case -kernel isn't needed), the code can still be useful.
> 
> If you'd prefer to make libfdt mandatory, I'm fine with that.
> 
> > > This patch introduces a dependency on libfdt for flat device tree support.
> > 
> > I don't like the way this is done.
> > 
> > AFAIK libfdt isn't present in any of the major distros. I thought the 
> > conclusion was that we should import libfdt into qemu.
> 
> That was our conclusion, but Anthony never agreed.
> 
> FWIW, I have requested that Fedora and Debian package libfdt, and they
> agreed in principle, but it's still missing in Fedora 10 for example.

If you've got a package review ticket open against Fedora for libfdt
inclusion, let me know the bug number and I'm happy to do the review,
so it is not unduely delayed on its path into Fedora repositories. 

I far far prefer to see this kind of thing properly packaged, than 
copied into the source tree. Indeed if any application copies another 
library's code into their source tree, then when we package that app 
for Fedora we typically try to reverse this and make it link against 
a proper separately packaged shared library. Copy+paste of libraries 
into other apps's source tree is a maintenance disaster, particularly
for security updates.

Regards,
Daniel
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