Re: [PATCH for 5.0 v1 2/2] riscv: AND stage-1 and stage-2 protection flags

[Alistair Francis]

On Thu, Mar 26, 2020 at 4:32 PM Richard Henderson
<address@hidden> wrote:
>
> On 3/26/20 3:44 PM, Alistair Francis wrote:
> > Take the result of stage-1 and stage-2 page table walks and AND the two
> > protection flags together. This way we require both to set permissions
> > instead of just stage-2.
> >
> > Signed-off-by: Alistair Francis <address@hidden>
> > ---
> >  target/riscv/cpu_helper.c | 8 +++++---
> >  1 file changed, 5 insertions(+), 3 deletions(-)
> >
> > diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
> > index f36d184b7b..50e13a064f 100644
> > --- a/target/riscv/cpu_helper.c
> > +++ b/target/riscv/cpu_helper.c
> > @@ -707,7 +707,7 @@ bool riscv_cpu_tlb_fill(CPUState *cs, vaddr address, 
> > int size,
> >  #ifndef CONFIG_USER_ONLY
> >      vaddr im_address;
> >      hwaddr pa = 0;
> > -    int prot;
> > +    int prot, prot2;
> >      bool pmp_violation = false;
> >      bool m_mode_two_stage = false;
> >      bool hs_mode_two_stage = false;
> > @@ -757,13 +757,15 @@ bool riscv_cpu_tlb_fill(CPUState *cs, vaddr address, 
> > int size,
> >              /* Second stage lookup */
> >              im_address = pa;
> >
> > -            ret = get_physical_address(env, &pa, &prot, im_address,
> > +            ret = get_physical_address(env, &pa, &prot2, im_address,
> >                                         access_type, mmu_idx, false, true);
> >
> >              qemu_log_mask(CPU_LOG_MMU,
> >                      "%s 2nd-stage address=%" VADDR_PRIx " ret %d physical "
> >                      TARGET_FMT_plx " prot %d\n",
> > -                    __func__, im_address, ret, pa, prot);
> > +                    __func__, im_address, ret, pa, prot2);
> > +
> > +            prot &= prot2;
> >
> >              if (riscv_feature(env, RISCV_FEATURE_PMP) &&
> >                  (ret == TRANSLATE_SUCCESS) &&
> >
>
> Whee!  Yes, I think this is what you've been looking for.

Yep!

I actually tried this ages ago, but it didn't work without the first
path so it never fixed the problem.

> Reviewed-by: Richard Henderson <address@hidden>

Thanks

Alistair

>
>
> r~