On Thu, Feb 06, 2014 at 10:43:28AM +0000, Catalin Marinas wrote:
> On Wed, Feb 05, 2014 at 07:55:45PM +0000, Marc Zyngier wrote:
> > The default pmd_addr_end macro uses an unsigned long to represent
> > the VA. When used with KVM and stage-2 translation, the VA is
> > actually an IPA, which is up to 40 bits. This also affect the
> > SMMU driver, which also deals with stage-2 translation.
> >
> > Instead, provide an implementation that can cope with larger VAs
> > by using a u64 instead. This version will overload the default
> > one provided in include/asm-generic/pgtable.h.
> >
> > Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
> > ---
> > arch/arm/include/asm/pgtable-3level.h | 5 +++++
> > 1 file changed, 5 insertions(+)
> >
> > diff --git a/arch/arm/include/asm/pgtable-3level.h b/arch/arm/include/asm/pgtable-3level.h
> > index 03243f7..594867b 100644
> > --- a/arch/arm/include/asm/pgtable-3level.h
> > +++ b/arch/arm/include/asm/pgtable-3level.h
> > @@ -262,6 +262,11 @@ static inline int has_transparent_hugepage(void)
> > return 1;
> > }
> >
> > +#define pmd_addr_end(addr, end) \
> > +({ u64 __boundary = ((addr) + PMD_SIZE) & PMD_MASK; \
> > + (__boundary - 1 < (end) - 1)? __boundary: (end); \
> > +})
>
> I see why you need this but it affects all the other uses of
> pmd_addr_end() with 32-bit VA. It would be slight performance, I don't
> think it's noticeable.
>
> A different approach could be something like (untested):
>
> #define pmd_addr_end(addr, end) \
> ({ __typeof__(addr) __boundary = ...
> ...
> })
>
> What about the pgd_addr_end(), do we need this or it's not used by KVM?
>
What about pud_addr_end(), is that defined as a noop on LPAE, or?
I would be in favor of introducing them all using your approach to avoid
somebody being inspired by the KVM code when dealing with IPAs and
breaking things unknowingly.
-Christoffer
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
