Re: [discuss] [patch] mtrr: fix issues with large addresses

Andreas Herrmann
2007-02-06T16:26:33Z

On Tue, Feb 06, 2007 at 11:54:57AM +0100, Andi Kleen wrote:
> On Tuesday 06 February 2007 10:53, Jan Beulich wrote:
> > >> I don't think I remember a restriction here, at least not below 44 bits
> > >> (that's where pfn-s would need to become 64-bit wide).
> > >
> > >The i386 mm code only supports 4 entries in the PGD, so more than 36bit cannot
> > >be mapped right now.
> >
> > That has nothing to do with the number of physical address bits.
>
> You couldn't use the memory in any ways.
>
> Anyways I give up -- the check is probably not needed, unless Andreas
> comes up with a good reason.

No, I haven't a good reason to restrict the base address to fewer
than 44 bits.

So the question is, should I completely remove that check or adapt it
to check for 44 bit instead of 36 bit?

Regards,

Andreas

--
AMD Saxony, Dresden, Germany
Operating System Research Center