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

Jeremy Fitzhardinge
2008-01-24T22:35:45Z

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).

J