Re: [PATCH 2/3] target/arm: ARMv8.4-TTST extension

[Richard Henderson]

On 12/18/20 6:33 AM, remi.denis.courmont@huawei.com wrote:
> From: Rémi Denis-Courmont <remi.denis.courmont@huawei.com>
> 
> This adds for the Small Translation tables extension in AArch64 state.
> 
> Signed-off-by: Rémi Denis-Courmont <remi.denis.courmont@huawei.com>
> ---
>  target/arm/cpu.h    |  5 +++++
>  target/arm/helper.c | 13 ++++++++++---
>  2 files changed, 15 insertions(+), 3 deletions(-)
> 
> diff --git a/target/arm/cpu.h b/target/arm/cpu.h
> index 39abb2a36b..604b9cdd0e 100644
> --- a/target/arm/cpu.h
> +++ b/target/arm/cpu.h
> @@ -3991,6 +3991,11 @@ static inline bool isar_feature_aa64_uao(const 
> ARMISARegisters *id)
>      return FIELD_EX64(id->id_aa64mmfr2, ID_AA64MMFR2, UAO) != 0;
>  }
>  
> +static inline bool isar_feature_aa64_st(const ARMISARegisters *id)
> +{
> +    return FIELD_EX64(id->id_aa64mmfr2, ID_AA64MMFR2, ST) != 0;
> +}
> +
>  static inline bool isar_feature_aa64_bti(const ARMISARegisters *id)
>  {
>      return FIELD_EX64(id->id_aa64pfr1, ID_AA64PFR1, BT) != 0;
> diff --git a/target/arm/helper.c b/target/arm/helper.c
> index b927e53ab0..c3a186db35 100644
> --- a/target/arm/helper.c
> +++ b/target/arm/helper.c
> @@ -10851,7 +10851,7 @@ static bool check_s2_mmu_setup(ARMCPU *cpu, bool 
> is_aa64, uint32_t level,
>              if (level == 0 && pamax <= 42) {
>                  return false;
>              }
> -            if (level == 3) {
> +            if (level == 3 && !cpu_isar_feature(aa64_st, cpu)) {
>                  return false;
>              }
>              break;

As mentioned vs patch 1, I think this hunk should be handled differently.

> @@ -10946,7 +10946,7 @@ ARMVAParameters aa64_va_parameters(CPUARMState *env, 
> uint64_t va,
>  {
>      uint64_t tcr = regime_tcr(env, mmu_idx)->raw_tcr;
>      bool epd, hpd, using16k, using64k;
> -    int select, tsz, tbi;
> +    int select, tsz, tbi, max_tsz;
>  
>      if (!regime_has_2_ranges(mmu_idx)) {
>          select = 0;
> @@ -10981,7 +10981,14 @@ ARMVAParameters aa64_va_parameters(CPUARMState *env, 
> uint64_t va,
>              hpd = extract64(tcr, 42, 1);
>          }
>      }
> -    tsz = MIN(tsz, 39);  /* TODO: ARMv8.4-TTST */
> +
> +    if (cpu_isar_feature(aa64_st, env_archcpu(env))) {
> +        max_tsz = 48 - using64k;
> +    } else {
> +        max_tsz = 39;
> +    }
> +
> +    tsz = MIN(tsz, max_tsz);
>      tsz = MAX(tsz, 16);  /* TODO: ARMv8.2-LVA  */
>  
>      /* Present TBI as a composite with TBID.  */
> 

But the rest of the patch looks good.


r~