On Wed, Oct 07, 2015 at 01:24:27PM +0100, Alex Bennée wrote:
>
> Edgar E. Iglesias <edgar.igles...@gmail.com> writes:
>
> > From: "Edgar E. Iglesias" <edgar.igles...@xilinx.com>
> >
> > The starting level for S2 pagetable walks is computed
> > differently from the S1 starting level. Implement the S2
> > variant.
> >
> > Signed-off-by: Edgar E. Iglesias <edgar.igles...@xilinx.com>
> > ---
> > target-arm/helper.c | 39 +++++++++++++++++++++++++++------------
> > 1 file changed, 27 insertions(+), 12 deletions(-)
> >
> > diff --git a/target-arm/helper.c b/target-arm/helper.c
> > index 5a5e5f0..507324f 100644
> > --- a/target-arm/helper.c
> > +++ b/target-arm/helper.c
> > @@ -6549,18 +6549,33 @@ static bool get_phys_addr_lpae(CPUARMState *env,
> > target_ulong address,
> > goto do_fault;
> > }
> >
> > - /* The starting level depends on the virtual address size (which can be
> > - * up to 48 bits) and the translation granule size. It indicates the
> > number
> > - * of strides (granule_sz bits at a time) needed to consume the bits
> > - * of the input address. In the pseudocode this is:
> > - * level = 4 - RoundUp((inputsize - grainsize) / stride)
> > - * where their 'inputsize' is our 'va_size - tsz', 'grainsize' is
> > - * our 'granule_sz + 3' and 'stride' is our 'granule_sz'.
> > - * Applying the usual "rounded up m/n is (m+n-1)/n" and simplifying:
> > - * = 4 - (va_size - tsz - granule_sz - 3 + granule_sz - 1) /
> > granule_sz
> > - * = 4 - (va_size - tsz - 4) / granule_sz;
> > - */
> > - level = 4 - (va_size - tsz - 4) / granule_sz;
> > + if (mmu_idx != ARMMMUIdx_S2NS) {
> > + /* The starting level depends on the virtual address size (which
> > can
> > + * be up to 48 bits) and the translation granule size. It indicates
> > + * the number of strides (granule_sz bits at a time) needed to
> > + * consume the bits of the input address. In the pseudocode this
> > is:
> > + * level = 4 - RoundUp((inputsize - grainsize) / stride)
> > + * where their 'inputsize' is our 'va_size - tsz', 'grainsize' is
> > + * our 'granule_sz + 3' and 'stride' is our 'granule_sz'.
> > + * Applying the usual "rounded up m/n is (m+n-1)/n" and
> > simplifying:
> > + * = 4 - (va_size - tsz - granule_sz - 3 + granule_sz - 1) /
> > granule_sz
> > + * = 4 - (va_size - tsz - 4) / granule_sz;
> > + */
> > + level = 4 - (va_size - tsz - 4) / granule_sz;
> > + } else {
> > + unsigned int startlevel = extract32(tcr->raw_tcr, 6, 2);
>
> Maybe an assert(startlevel<3) would be useful?
Good catch here. There is actually a trap for some of the bad startlevel cases.
I'll implement that for the next version.
>
> > +
> > + /* For stage 2 translations the starting level is specified by the
> > + * VCTR_EL2.SL0 field (whose interpretation depends on the page
> > size)
> > + */
> > + if (granule_sz == 9) {
> > + /* 4K pages */
> > + level = 2 - startlevel;
> > + } else {
> > + /* 16K or 64K pages */
> > + level = 3 - startlevel;
> > + }
> > + }
> >
> > /* Clear the vaddr bits which aren't part of the within-region address,
> > * so that we don't have to special case things when calculating the
>
> Reviewed-by: Alex Bennée <alex.ben...@linaro.org>
Thanks, I'll hold the RB until you see the next version with the traps for bad
start-levels.
Cheers,
Edgar
