Re: [PATCH v1 3/3] target-arm: Implement the S2 MMU inputsize < pamax check

["Edgar E. Iglesias" <edgar.iglesias@gmail.com>]

On Thu, Jan 21, 2016 at 12:52:54PM +0000, Alex Bennée wrote:
> 
> Edgar E. Iglesias <edgar.iglesias@gmail.com> writes:
> 
> > On Wed, Jan 20, 2016 at 02:49:40PM +0100, Edgar E. Iglesias wrote:
> >> From: "Edgar E. Iglesias" <edgar.iglesias@xilinx.com>
> >>
> >> Implement the inputsize < pamax check for Stage 2 translations.
> >> We have multiple choices for how to respond to errors and
> >> choose to fault.
> >>
> >> Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
> >> ---
> >>  target-arm/helper.c | 15 +++++++++++----
> >>  1 file changed, 11 insertions(+), 4 deletions(-)
> >>
> >> diff --git a/target-arm/helper.c b/target-arm/helper.c
> >> index 4abeb4d..e1fa209 100644
> >> --- a/target-arm/helper.c
> >> +++ b/target-arm/helper.c
> >> @@ -6808,7 +6808,7 @@ static bool get_phys_addr_lpae(CPUARMState *env, target_ulong address,
> >>           */
> >>          int startlevel = extract32(tcr->raw_tcr, 6, 2);
> >>          unsigned int pamax = arm_pamax(cpu);
> >> -        bool ok;
> >> +        bool ok = true;
> >>
> >>          if (va_size == 32 || stride == 9) {
> >>              /* AArch32 or 4KB pages */
> >> @@ -6818,9 +6818,16 @@ static bool get_phys_addr_lpae(CPUARMState *env, target_ulong address,
> >>              level = 3 - startlevel;
> >>          }
> >>
> >> -        /* Check that the starting level is valid. */
> >> -        ok = check_s2_startlevel(cpu, va_size == 64, level,
> >> -                                 inputsize, stride, pamax);
> >> +        if (inputsize > pamax &&
> >> +            (arm_el_is_aa64(env, 1) || inputsize > 40)) {
> >
> > I realized that this check should only be done for AArch64...
> > Will fix that for v2.
> >
> > Something like the following:
> >
> >         if (arm_el_is_aa64(env, el) &&
> >             inputsize > pamax &&
> >             (arm_el_is_aa64(env, 1) || inputsize > 40)) {
> >             /* We have multiple choices but choose to fault.  */
> >             ok = false;
> >         }
> >
> 
> OK, I'll await the next revision.

I posted a v2 earlier today, let me know if you didn't
receive it!

Cheers,
Edgar

> 
> >
> > Cheers,
> > Edgar
> >
> >
> >> +            /* We have multiple choices but choose to fault.  */
> >> +            ok = false;
> >> +        }
> >> +        if (ok) {
> >> +            /* Check that the starting level is valid. */
> >> +            ok = check_s2_startlevel(cpu, va_size == 64, level,
> >> +                                     inputsize, stride, pamax);
> >> +        }
> >>          if (!ok) {
> >>              /* AArch64 reports these as level 0 faults.
> >>               * AArch32 reports these as level 1 faults.
> >> --
> >> 1.9.1
> >>
> 
> 
> --
> Alex Bennée