Re: [PATCH] x86: Construct 32 bit boot time page tables in native format.

H. Peter Anvin
2008-01-24T22:44:38Z

Jeremy Fitzhardinge wrote:
> H. Peter Anvin wrote:
>> In other words, reusing the early page tables isn't all that
>> straightforward. It may easily be that it's better to build a new set
>> of page tables from scratch, however, it would *still* be beneficial
>> to have the early page tables be in the same format as the later one,
>> since it lets us use the fixmap area, and therefore
>> {bt,early}_ioremap() much sooner.
>
> Yes, and it simplifies Xen as it always starts guest domains in the
> appropriate pagetable mode and doesn't let the guest change it on the
> fly. If early_ioremap depends on non-PAE early pagetables in an
> otherwise PAE kernel, we'd need to go to some effort to make sure all
> the early_ioremap stuff is skipped (which would be possible but
> unpleasant for domU, but very bad in dom0).
>

Yeah, and it's ugly for the kernel proper, so that bit is a no-brainer.
It's just a matter of hammering out the details.

It doesn't sound from the above that you have any opinion either way
about reusing the initial page tables or creating a new set, as long as
they're in the same format.

-hpa