Re: [PATCH 1/2] x86, ioapic: Reserve only 128 bytes for IOAPICs

Cyrill Gorcunov
2011-08-26T06:48:44Z

On Thu, Aug 25, 2011 at 06:41:57PM -0700, H. Peter Anvin wrote:
> On 08/25/2011 05:17 PM, Bjorn Helgaas wrote:
> >
> > If the OS allocated the next 128 bytes to another device, it sounds
> > like it would cause a conflict on Intel boxes. This must be an area
> > that differs between vendors. I haven't seen a spec that mentions 256
> > bytes as the required minimum MMIO size for IOAPICs, and apparently
> > the AMD IOAPIC decodes 240 bytes or fewer.
> >
>
> For what it's worth, it's probably a bad idea on x86 for the OS to
> allocate addresses in the 0xFExxxxxx range...
>
> -hpa
>

I rather wonder if there a way to assign a different address for the
watchdog Bjorn referring to. I don't have such machine to test but
seems its base address is configurable via pmio. Just curious.

Cyrill