Re: [PATCH v11 4/5] target/riscv: smstateen check for fcsr

[Alistair Francis <alistair23@gmail.com>]

On Sun, Oct 16, 2022 at 11:09 PM Mayuresh Chitale
<mchitale@ventanamicro.com> wrote:
>
> If smstateen is implemented and sstateen0.fcsr is clear then the floating point
> operations must return illegal instruction exception or virtual instruction
> trap, if relevant.
>
> Signed-off-by: Mayuresh Chitale <mchitale@ventanamicro.com>
> Reviewed-by: Weiwei Li <liweiwei@iscas.ac.cn>
> ---
>  target/riscv/csr.c                        | 23 ++++++++++++
>  target/riscv/insn_trans/trans_rvf.c.inc   | 43 +++++++++++++++++++++--
>  target/riscv/insn_trans/trans_rvzfh.c.inc | 12 +++++++
>  3 files changed, 75 insertions(+), 3 deletions(-)
>
> diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> index 71236f2b5d..8b25f885ec 100644
> --- a/target/riscv/csr.c
> +++ b/target/riscv/csr.c
> @@ -84,6 +84,10 @@ static RISCVException fs(CPURISCVState *env, int csrno)
>          !RISCV_CPU(env_cpu(env))->cfg.ext_zfinx) {
>          return RISCV_EXCP_ILLEGAL_INST;
>      }
> +
> +    if (!env->debugger && !riscv_cpu_fp_enabled(env)) {
> +        return smstateen_acc_ok(env, 0, SMSTATEEN0_FCSR);
> +    }
>  #endif
>      return RISCV_EXCP_NONE;
>  }
> @@ -2023,6 +2027,9 @@ static RISCVException write_mstateen0(CPURISCVState *env, int csrno,
>                                        target_ulong new_val)
>  {
>      uint64_t wr_mask = SMSTATEEN_STATEEN | SMSTATEEN0_HSENVCFG;
> +    if (!riscv_has_ext(env, RVF)) {
> +        wr_mask |= SMSTATEEN0_FCSR;
> +    }
>
>      return write_mstateen(env, csrno, wr_mask, new_val);
>  }
> @@ -2059,6 +2066,10 @@ static RISCVException write_mstateen0h(CPURISCVState *env, int csrno,
>  {
>      uint64_t wr_mask = SMSTATEEN_STATEEN | SMSTATEEN0_HSENVCFG;
>
> +    if (!riscv_has_ext(env, RVF)) {
> +        wr_mask |= SMSTATEEN0_FCSR;
> +    }
> +
>      return write_mstateenh(env, csrno, wr_mask, new_val);
>  }
>
> @@ -2096,6 +2107,10 @@ static RISCVException write_hstateen0(CPURISCVState *env, int csrno,
>  {
>      uint64_t wr_mask = SMSTATEEN_STATEEN | SMSTATEEN0_HSENVCFG;
>
> +    if (!riscv_has_ext(env, RVF)) {
> +        wr_mask |= SMSTATEEN0_FCSR;
> +    }
> +
>      return write_hstateen(env, csrno, wr_mask, new_val);
>  }
>
> @@ -2135,6 +2150,10 @@ static RISCVException write_hstateen0h(CPURISCVState *env, int csrno,
>  {
>      uint64_t wr_mask = SMSTATEEN_STATEEN | SMSTATEEN0_HSENVCFG;
>
> +    if (!riscv_has_ext(env, RVF)) {
> +        wr_mask |= SMSTATEEN0_FCSR;
> +    }
> +
>      return write_hstateenh(env, csrno, wr_mask, new_val);
>  }
>
> @@ -2182,6 +2201,10 @@ static RISCVException write_sstateen0(CPURISCVState *env, int csrno,
>  {
>      uint64_t wr_mask = SMSTATEEN_STATEEN | SMSTATEEN0_HSENVCFG;
>
> +    if (!riscv_has_ext(env, RVF)) {
> +        wr_mask |= SMSTATEEN0_FCSR;
> +    }
> +
>      return write_sstateen(env, csrno, wr_mask, new_val);
>  }
>
> diff --git a/target/riscv/insn_trans/trans_rvf.c.inc b/target/riscv/insn_trans/trans_rvf.c.inc
> index a1d3eb52ad..93657680c6 100644
> --- a/target/riscv/insn_trans/trans_rvf.c.inc
> +++ b/target/riscv/insn_trans/trans_rvf.c.inc
> @@ -24,9 +24,46 @@
>              return false; \
>  } while (0)
>
> -#define REQUIRE_ZFINX_OR_F(ctx) do {\
> -    if (!ctx->cfg_ptr->ext_zfinx) { \
> -        REQUIRE_EXT(ctx, RVF); \
> +#ifndef CONFIG_USER_ONLY
> +static inline bool smstateen_fcsr_check(DisasContext *ctx, int index)
> +{
> +    CPUState *cpu = ctx->cs;
> +    CPURISCVState *env = cpu->env_ptr;
> +    uint64_t stateen = env->mstateen[index];

Sorry I missed this the first time around. You can't access env here

Richard pointed it out here:
https://patchwork.kernel.org/project/qemu-devel/patch/20221117070316.58447-8-liweiwei@iscas.ac.cn/#25095773

I'm going to drop this patch and patch v5

Alistair