Re: [PATCH V3 5/6] target/riscv: Fix checks in hmode/hmode32

[Alistair Francis]

On Mon, Jul 18, 2022 at 11:13 PM Weiwei Li <liweiwei@iscas.ac.cn> wrote:
>
> Add check for the implicit dependence between H and S
>
> Csrs only existed in RV32 will not trigger virtual instruction fault
> when not in RV32 based on section 8.6.1 of riscv-privileged spec
> (draft-20220717)
>
> Signed-off-by: Weiwei Li <liweiwei@iscas.ac.cn>
> Signed-off-by: Junqiang Wang <wangjunqiang@iscas.ac.cn>
> Reviewed-by: Andrew Jones <ajones@ventanamicro.com>

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

> ---
>  target/riscv/cpu.c | 5 +++++
>  target/riscv/csr.c | 9 ++-------
>  2 files changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> index b8ce0959cb..455787a940 100644
> --- a/target/riscv/cpu.c
> +++ b/target/riscv/cpu.c
> @@ -738,6 +738,11 @@ static void riscv_cpu_realize(DeviceState *dev, Error 
> **errp)
>              return;
>          }
>
> +        if (cpu->cfg.ext_h && !cpu->cfg.ext_s) {
> +            error_setg(errp, "H extension implicitly requires S-mode");
> +            return;
> +        }
> +
>          if (cpu->cfg.ext_f && !cpu->cfg.ext_icsr) {
>              error_setg(errp, "F extension requires Zicsr");
>              return;
> diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> index 5c69dc838c..cf15aa67b7 100644
> --- a/target/riscv/csr.c
> +++ b/target/riscv/csr.c
> @@ -311,8 +311,7 @@ static int aia_smode32(CPURISCVState *env, int csrno)
>
>  static RISCVException hmode(CPURISCVState *env, int csrno)
>  {
> -    if (riscv_has_ext(env, RVS) &&
> -        riscv_has_ext(env, RVH)) {
> +    if (riscv_has_ext(env, RVH)) {
>          /* Hypervisor extension is supported */
>          if ((env->priv == PRV_S && !riscv_cpu_virt_enabled(env)) ||
>              env->priv == PRV_M) {
> @@ -328,11 +327,7 @@ static RISCVException hmode(CPURISCVState *env, int 
> csrno)
>  static RISCVException hmode32(CPURISCVState *env, int csrno)
>  {
>      if (riscv_cpu_mxl(env) != MXL_RV32) {
> -        if (!riscv_cpu_virt_enabled(env)) {
> -            return RISCV_EXCP_ILLEGAL_INST;
> -        } else {
> -            return RISCV_EXCP_VIRT_INSTRUCTION_FAULT;
> -        }
> +        return RISCV_EXCP_ILLEGAL_INST;
>      }
>
>      return hmode(env, csrno);
> --
> 2.17.1
>
>