Re: [PATCH v5 6/6] mtrr, mm, x86: Enhance MTRR checks for KVA huge page mapping

Toshi Kani
2015-05-19T14:06:34Z

On Tue, 2015-05-19 at 15:23 +0200, Borislav Petkov wrote:
> On Tue, May 19, 2015 at 01:44:37PM +0200, Borislav Petkov wrote:
> > > Try with a smaller page size.
> > >
> > > The callers, pud_set_huge() and pmd_set_huge(), check if the given range
> > > is safe with MTRRs for creating a huge page mapping. If not, they fail
> > > the request, which leads their callers, ioremap_pud_range() and
> > > ioremap_pmd_range(), to retry with a smaller page size, i.e. 1GB -> 2MB
> > > -> 4KB. 4KB may not have overlap with MTRRs (hence no checking is
> > > necessary), which will succeed as before.
>
> Scratch that, I think I have it now. And I even have a good feeling
> about it :-)

Looks good. Thanks for the update!
-Toshi