[coreboot] Resource Allocation discussion

Myles Watson mylesgw at gmail.com
Tue Dec 2 20:09:09 CET 2008


On Tue, Dec 2, 2008 at 11:59 AM, Marc Jones <marcj303 at gmail.com> wrote:

> On Tue, Dec 2, 2008 at 11:06 AM, Myles Watson <mylesgw at gmail.com> wrote:
> > Here's the read_resources code from qemu after my latest patch.  Is this
> > what people are thinking?  Notice that I explicitly allocate VGA space
> and
> > APIC.  At the end of the code I'm pasting in a snippet of the log that
> shows
> > the resources after they are assigned values.
>
> I think I like this. It makes sense to me. The legacy VGA space nadd
> the legacy IO space should be reserved in the southbridge as you have
> done.

I actually think I just bumped up the base in the northbridge this time
around.


> The IOAPIC address should be held by the southbridge since that
> is where it is a located.

OK.

The LAPIC should probably be in the
> CPU/northbridge device.

So I got this one right?  No I put it in the domain.


>
> It would be handy to show the fixed resources in the output.


Because of a typo the two APIC reservations clobbered each other, so only
one is there.  The rest of the fixed allocations should be there.

>
> > Show resources in subtree (root)...After assigning values.
> >  Root Device links 1 child on link 0 cpus
> >  Root Device resource base 1000 size 410 align 8 gran 0 limit ffff flags
> > 80100 index 0
>
> Coreboot allocates IO from the bottom (0x1000) up?

Yes.


> I think it should
> allocate top down as it does with memory. I think that the rule is
> that the BIOS allocates top down and the OS allocates bottom up.


I don't think that would match v2 or the factory BIOS for serengeti or
qemu.  Is there a packing reason?

Thanks,
Myles
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