Re: [Qemu-devel] [PATCH v1 13/30] RISC-V: Implement mstatus.TSR/TW/TVM

[Philippe Mathieu-Daudé]

Hi Michael,

On 05/22/2018 09:15 PM, Michael Clark wrote:
> This adds the necessary minimum to support S-mode
> virtualization for priv ISA >= v1.10
> 
> Cc: Sagar Karandikar <address@hidden>
> Cc: Bastian Koppelmann <address@hidden>
> Cc: Palmer Dabbelt <address@hidden>
> Cc: Alistair Francis <address@hidden>
> Cc: Matthew Suozzo <address@hidden>
> Signed-off-by: Michael Clark <address@hidden>
> 
> Co-authored-by: Matthew Suozzo <address@hidden>

Isn't it simply another Signed-off-by?

> Co-authored-by: Michael Clark <address@hidden>
> ---
>  target/riscv/csr.c       | 17 +++++++++++++----
>  target/riscv/op_helper.c | 25 +++++++++++++++++++++----
>  2 files changed, 34 insertions(+), 8 deletions(-)
> 
> diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> index b4452388ff02..509215327243 100644
> --- a/target/riscv/csr.c
> +++ b/target/riscv/csr.c
> @@ -313,7 +313,8 @@ static int write_mstatus(CPURISCVState *env, int csrno, 
> target_ulong val)
>          }
>          mask = MSTATUS_SIE | MSTATUS_SPIE | MSTATUS_MIE | MSTATUS_MPIE |
>              MSTATUS_SPP | MSTATUS_FS | MSTATUS_MPRV | MSTATUS_SUM |
> -            MSTATUS_MPP | MSTATUS_MXR;
> +            MSTATUS_MPP | MSTATUS_MXR | MSTATUS_TVM | MSTATUS_TSR |
> +            MSTATUS_TW;
>      }
>  
>      /* silenty discard mstatus.mpp writes for unsupported modes */
> @@ -654,7 +655,11 @@ static int read_satp(CPURISCVState *env, int csrno, 
> target_ulong *val)
>      if (!riscv_feature(env, RISCV_FEATURE_MMU)) {
>          *val = 0;
>      } else if (env->priv_ver >= PRIV_VERSION_1_10_0) {
> -        *val = env->satp;
> +        if (env->priv == PRV_S && get_field(env->mstatus, MSTATUS_TVM)) {
> +            return -1;
> +        } else {
> +            *val = env->satp;
> +        }
>      } else {
>          *val = env->sptbr;
>      }
> @@ -675,8 +680,12 @@ static int write_satp(CPURISCVState *env, int csrno, 
> target_ulong val)
>          validate_vm(env, get_field(val, SATP_MODE)) &&
>          ((val ^ env->satp) & (SATP_MODE | SATP_ASID | SATP_PPN)))
>      {
> -        tlb_flush(CPU(riscv_env_get_cpu(env)));
> -        env->satp = val;
> +        if (env->priv == PRV_S && get_field(env->mstatus, MSTATUS_TVM)) {
> +            return -1;
> +        } else {
> +            tlb_flush(CPU(riscv_env_get_cpu(env)));
> +            env->satp = val;
> +        }
>      }
>      return 0;
>  }
> diff --git a/target/riscv/op_helper.c b/target/riscv/op_helper.c
> index 81bd1a77ea90..77c79ba36e0b 100644
> --- a/target/riscv/op_helper.c
> +++ b/target/riscv/op_helper.c
> @@ -82,6 +82,11 @@ target_ulong helper_sret(CPURISCVState *env, target_ulong 
> cpu_pc_deb)
>          do_raise_exception_err(env, RISCV_EXCP_INST_ADDR_MIS, GETPC());
>      }
>  
> +    if (env->priv_ver >= PRIV_VERSION_1_10_0 &&
> +        get_field(env->mstatus, MSTATUS_TSR)) {
> +        do_raise_exception_err(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
> +    }
> +
>      target_ulong mstatus = env->mstatus;
>      target_ulong prev_priv = get_field(mstatus, MSTATUS_SPP);
>      mstatus = set_field(mstatus,
> @@ -125,16 +130,28 @@ void helper_wfi(CPURISCVState *env)
>  {
>      CPUState *cs = CPU(riscv_env_get_cpu(env));
>  
> -    cs->halted = 1;
> -    cs->exception_index = EXCP_HLT;
> -    cpu_loop_exit(cs);
> +    if (env->priv == PRV_S &&
> +        env->priv_ver >= PRIV_VERSION_1_10_0 &&
> +        get_field(env->mstatus, MSTATUS_TW)) {
> +        do_raise_exception_err(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
> +    } else {
> +        cs->halted = 1;
> +        cs->exception_index = EXCP_HLT;
> +        cpu_loop_exit(cs);
> +    }
>  }
>  
>  void helper_tlb_flush(CPURISCVState *env)
>  {
>      RISCVCPU *cpu = riscv_env_get_cpu(env);
>      CPUState *cs = CPU(cpu);
> -    tlb_flush(cs);
> +    if (env->priv == PRV_S &&
> +        env->priv_ver >= PRIV_VERSION_1_10_0 &&
> +        get_field(env->mstatus, MSTATUS_TVM)) {
> +        do_raise_exception_err(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
> +    } else {
> +        tlb_flush(cs);
> +    }
>  }
>  
>  #endif /* !CONFIG_USER_ONLY */
>