Re: 2.6.25-rc1 xen pvops regression

H. Peter Anvin
2008-02-21T22:01:47Z

Jeremy Fitzhardinge wrote:
> H. Peter Anvin wrote:
>>> Still curious about why a pagetable page is ending up in that range
>>> though. Seems like it shouldn't be possible, since we shouldn't be
>>> allowed to allocate from those pages, at least until the DMI probe
>>> has happened... Unless the early allocator is only excluded from
>>> e820 reserved pages, which would cause a problem on systems which
>>> don't reserve the DMI space... HPA?
>>>
>>
>> I thought the problem was a Xen-provided pagetable from before Linux
>> started?
>
> Hm, I don't think so. The domain-builder pagetable is put after the
> kernel, so it shouldn't be under 1M.
>

That's weird, then. If we put a page table at 0xf0000, it would crash
hard on real hardware (there is ROM there); as I mentioned, I do have
hardware which both reserves and doesn't reserve this region.

-hpa