Re: [PATCH 2/6] target/riscv: Fix the relationship of PBMTE/STCE fields between menvcfg and henvcfg

[Andrew Jones]

On Fri, Feb 24, 2023 at 12:08:48PM +0800, Weiwei Li wrote:
> henvcfg.PBMTE/STCE are read-only zero if menvcfg.PBMTE/STCE are zero.
> 
> Signed-off-by: Weiwei Li <liweiwei@iscas.ac.cn>
> Signed-off-by: Junqiang Wang <wangjunqiang@iscas.ac.cn>
> ---
>  target/riscv/csr.c | 13 +++++++++----
>  1 file changed, 9 insertions(+), 4 deletions(-)
> 
> diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> index feae23cab0..02cb2c2bb7 100644
> --- a/target/riscv/csr.c
> +++ b/target/riscv/csr.c
> @@ -1956,7 +1956,11 @@ static RISCVException read_henvcfg(CPURISCVState *env, 
> int csrno,
>          return ret;
>      }
>  
> -    *val = env->henvcfg;
> +    /*
> +     * henvcfg.pbmte is read_only 0 when menvcfg.pbmte = 0
> +     * henvcfg.stce is read_only 0 when menvcfg.stce = 0
> +     */
> +    *val = env->henvcfg & (~(HENVCFG_PBMTE | HENVCFG_STCE) | env->menvcfg);
>      return RISCV_EXCP_NONE;
>  }
>  
> @@ -1972,7 +1976,7 @@ static RISCVException write_henvcfg(CPURISCVState *env, 
> int csrno,
>      }
>  
>      if (riscv_cpu_mxl(env) == MXL_RV64) {
> -        mask |= HENVCFG_PBMTE | HENVCFG_STCE;
> +        mask |= env->menvcfg & (HENVCFG_PBMTE | HENVCFG_STCE);

nit:

  While HENVCFG_PBMTE == MENVCFG_PBMTE, I'd prefer we use
  MENVCFG_* with menvcfg and HENVCFG_* with henvcfg.

>      }
>  
>      env->henvcfg = (env->henvcfg & ~mask) | (val & mask);
> @@ -1990,14 +1994,15 @@ static RISCVException read_henvcfgh(CPURISCVState 
> *env, int csrno,
>          return ret;
>      }
>  
> -    *val = env->henvcfg >> 32;
> +    *val = (env->henvcfg & (~(HENVCFG_PBMTE | HENVCFG_STCE) |
> +                            env->menvcfg)) >> 32;
>      return RISCV_EXCP_NONE;
>  }
>  
>  static RISCVException write_henvcfgh(CPURISCVState *env, int csrno,
>                                    target_ulong val)
>  {
> -    uint64_t mask = HENVCFG_PBMTE | HENVCFG_STCE;
> +    uint64_t mask = env->menvcfg & (HENVCFG_PBMTE | HENVCFG_STCE);
>      uint64_t valh = (uint64_t)val << 32;
>      RISCVException ret;
>  
> -- 
> 2.25.1
> 
> 

Thanks,
drew