[SeaBIOS] [PATCHv2 0/6] Improved multi-platform support

[Ian Campbell]

On Thu, 2013-02-14 at 13:05 +0000, David Woodhouse wrote:
> On Thu, 2013-02-14 at 12:53 +0000, Ian Campbell wrote:
> > 
> > I had observed once upon a time that turning up the limit caused odd
> > failures, but I'd never associated it with the size. I spent ages
> > trying
> > to track down a NULL pointer in some level>3 message and the like...
> > 
> > In hvmloader I see:
> >         #define SEABIOS_PHYSICAL_ADDRESS    0x000E0000
> > which would have to change if the image grew >128K. Really hvmloader
> > should check the size dynamically and DTRT. I can't remember why I did
> > it this way.
> 
> No idea. If I just set .bios_address = 0x100000U - sizeof(seabios),
> it works just fine.
> 
> > Sorry about this, crapness on our end I think :-(
> 
> Ahem, you also have
> //BUILD_BUG_ON(sizeof(seabios) > (0x00100000U - SEABIOS_PHYSICAL_ADDRESS));
> 
> Now *that* would have been a time-saver... 

Oh god, sorry.

> Another observation: 'xl -c seabios.cfg' misses the first output of the
> domain. Starting it *paused*, then running 'xl unpause seabios' in
> another terminal, lets me catch even the first 'Start bios ...' message.
> 
> If it *had* been crashing early in SeaBIOS, I'd have been cursing you
> for that one too :)

Justifiably so I think.

> Anyway, I appear to have established that the qemu fw_cfg *doesn't*
> exist in your domains — so how you pass bootorder to the guest, if you
> successfully do so at all, I have no idea. And the patch at
> http://git.infradead.org/users/dwmw2/seabios.git/commitdiff/e62d1720f
> appears to work fine — at least in the case of a domain with nothing to
> actually boot from anyway, where we expect it just to die with 'no
> bootable device'.

Erm, this might be something we Xen folks need to fix! I'm not sure if
that fix will involve using fwcfg or not...

> I'll probably have a look at OVMF under Xen now, and making sure that my
> CSM code works there. Then you shouldn't need to offer people the choice
> between OVMF and SeaBIOS because you'll have one image that handles
> everything (which is what people get on real hardware, and expect).

That would be pretty sweet, thanks!

-- 
Ian Campbell
Current Noise: Pink Floyd - Shine On You Crazy Diamond (Parts 1-7)

All language designers are arrogant.  Goes with the territory... :-)
		-- Larry Wall in <1991Jul13.010945.19157 at netlabs.com