Re: [coreboot] I've turned on paging as a test

[David Woodhouse]

On Mon, 2014-03-10 at 16:41 -0500, Jonathan A. Kollasch wrote:
> On Mon, Mar 10, 2014 at 02:33:41PM -0700, ron minnich wrote:
> > And locked out page zero. And we trap.
> >
> > So, first question, can we move X86_BDA_BASE to somewhere other than 0x400?
> > Anyone know?
>
> The BIOS Data Area is not movable.

The *physical* address of the BDA is not movable.

However there are no constraints on what its *virtual* address should
be, while you're running in your own code with paging turned on.

Even if you generally have a 1:1 mapping of virt->phys addresses, you
could still set up a mapping for the zero page at a different virtual
address.