Re: [PATCH v6 3/5] target/riscv: smstateen check for fcsr

[Mayuresh Chitale]

On Fri, 2022-07-22 at 09:42 +0800, Weiwei Li wrote:
> 在 2022/7/21 下午11:31, Mayuresh Chitale 写道:
> > If smstateen is implemented and sstateen0.fcsr is clear then the
> > floating point operations must return illegal instruction
> > exception.
> > 
> > Signed-off-by: Mayuresh Chitale <mchitale@ventanamicro.com>
> > ---
> >   target/riscv/csr.c                        | 23 ++++++++++++++
> >   target/riscv/insn_trans/trans_rvf.c.inc   | 38
> > +++++++++++++++++++++--
> >   target/riscv/insn_trans/trans_rvzfh.c.inc |  4 +++
> >   3 files changed, 63 insertions(+), 2 deletions(-)
> > 
> > diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> > index ab06b117f9..a597b6cbc7 100644
> > --- a/target/riscv/csr.c
> > +++ b/target/riscv/csr.c
> > @@ -96,6 +96,10 @@ 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;
> >   }
> > @@ -1876,6 +1880,9 @@ static RISCVException
> > write_mstateen0(CPURISCVState *env, int csrno,
> >                                         target_ulong new_val)
> >   {
> >       uint64_t wr_mask = SMSTATEEN_STATEN | SMSTATEEN0_HSENVCFG;
> > +    if (!riscv_has_ext(env, RVF)) {
> > +        wr_mask |= SMSTATEEN0_FCSR;
> > +    }
> >   
> >       return write_mstateen(env, csrno, wr_mask, new_val);
> >   }
> > @@ -1924,6 +1931,10 @@ static RISCVException
> > write_mstateen0h(CPURISCVState *env, int csrno,
> >   {
> >       uint64_t wr_mask = SMSTATEEN_STATEN | SMSTATEEN0_HSENVCFG;
> >   
> > +    if (!riscv_has_ext(env, RVF)) {
> > +        wr_mask |= SMSTATEEN0_FCSR;
> > +    }
> > +
> >       return write_mstateenh(env, csrno, wr_mask, new_val);
> >   }
> >   
> > @@ -1973,6 +1984,10 @@ static RISCVException
> > write_hstateen0(CPURISCVState *env, int csrno,
> >   {
> >       uint64_t wr_mask = SMSTATEEN_STATEN | SMSTATEEN0_HSENVCFG;
> >   
> > +    if (!riscv_has_ext(env, RVF)) {
> > +        wr_mask |= SMSTATEEN0_FCSR;
> > +    }
> > +
> >       return write_hstateen(env, csrno, wr_mask, new_val);
> >   }
> >   
> > @@ -2024,6 +2039,10 @@ static RISCVException
> > write_hstateen0h(CPURISCVState *env, int csrno,
> >   {
> >       uint64_t wr_mask = SMSTATEEN_STATEN | SMSTATEEN0_HSENVCFG;
> >   
> > +    if (!riscv_has_ext(env, RVF)) {
> > +        wr_mask |= SMSTATEEN0_FCSR;
> > +    }
> > +
> >       return write_hstateenh(env, csrno, wr_mask, new_val);
> >   }
> >   
> > @@ -2083,6 +2102,10 @@ static RISCVException
> > write_sstateen0(CPURISCVState *env, int csrno,
> >   {
> >       uint64_t wr_mask = SMSTATEEN_STATEN | 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..c43c48336b 100644
> > --- a/target/riscv/insn_trans/trans_rvf.c.inc
> > +++ b/target/riscv/insn_trans/trans_rvf.c.inc
> > @@ -24,9 +24,43 @@
> >               return false; \
> >   } while (0)
> >   
> > +#ifndef CONFIG_USER_ONLY
> > +#define SMSTATEEN_CHECK(ctx) do {\
> > +    CPUState *cpu = ctx->cs; \
> > +    CPURISCVState *env = cpu->env_ptr; \
> > +    if (ctx->cfg_ptr->ext_smstateen && \
> > +        (env->priv < PRV_M)) { \
> > +        uint64_t stateen = env->mstateen[0]; \
> > +        uint64_t hstateen = env->hstateen[0]; \
> > +        uint64_t sstateen = env->sstateen[0]; \
> > +        if (!(stateen & SMSTATEEN_STATEN)) {\
> > +            hstateen = 0; \
> > +            sstateen = 0; \
> > +        } \
> > +        if (ctx->virt_enabled) { \
> > +            stateen &= hstateen; \
> > +            if (!(hstateen & SMSTATEEN_STATEN)) {\
> > +                sstateen = 0; \
> > +            } \
> > +        } \
> > +        if (env->priv == PRV_U && has_ext(ctx, RVS)) {\eventually
> > meaning
> > +            stateen &= sstateen; \
> > +        } \
> > +        if (!(stateen & SMSTATEEN0_FCSR)) { \
> > +            return false; \
> > +        } \
> > +    } \
> > +} while (0)
> 
> It's better to add a space before '\'.
ok. will modify in the next version.
> 
> > +#else
> > +#define SMSTATEEN_CHECK(ctx)
> > +#endif
> > +
> >   #define REQUIRE_ZFINX_OR_F(ctx) do {\
> > -    if (!ctx->cfg_ptr->ext_zfinx) { \
> > -        REQUIRE_EXT(ctx, RVF); \
> > +    if (!has_ext(ctx, RVF)) { \
> > +        SMSTATEEN_CHECK(ctx); \
> > +        if (!ctx->cfg_ptr->ext_zfinx) { \
> > +            return false; \
> > +        } \
> >       } \
> >   } while (0)
> 
> SMSTATEEN_CHECK is for CSR. and REQUIRE_ZFINX_OR_F is for Extension.
> I think It's better to separate them. By the way, if we want the
> smallest modification
> for current code, adding it to REQUIRE_FPU seems better.
Actually REQUIRE_FPU is checking for mstatus.fs but as per smstateen
spec we need to check for misa.f which is done in REQUIRE_ZFINX_OR_F.
> Regards,
> Weiwei Li
> 
> >   
> > diff --git a/target/riscv/insn_trans/trans_rvzfh.c.inc
> > b/target/riscv/insn_trans/trans_rvzfh.c.inc
> > index 5d07150cd0..b165ea9d58 100644
> > --- a/target/riscv/insn_trans/trans_rvzfh.c.inc
> > +++ b/target/riscv/insn_trans/trans_rvzfh.c.inc
> > @@ -17,24 +17,28 @@
> >    */
> >   
> >   #define REQUIRE_ZFH(ctx) do { \
> > +    SMSTATEEN_CHECK(ctx); \
> >       if (!ctx->cfg_ptr->ext_zfh) {      \
> >           return false;         \
> >       }                         \
> >   } while (0)
> >   
> >   #define REQUIRE_ZHINX_OR_ZFH(ctx) do { \
> > +    SMSTATEEN_CHECK(ctx); \
> >       if (!ctx->cfg_ptr->ext_zhinx && !ctx->cfg_ptr->ext_zfh) { \
> >           return false;                  \
> >       }                                  \
> >   } while (0)
> >   
> >   #define REQUIRE_ZFH_OR_ZFHMIN(ctx) do {       \
> > +    SMSTATEEN_CHECK(ctx); \
> >       if (!(ctx->cfg_ptr->ext_zfh || ctx->cfg_ptr->ext_zfhmin)) { \
> >           return false;                         \
> >       }                                         \
> >   } while (0)
> >   
> >   #define REQUIRE_ZFH_OR_ZFHMIN_OR_ZHINX_OR_ZHINXMIN(ctx) do { \
> > +    SMSTATEEN_CHECK(ctx); \
> >       if (!(ctx->cfg_ptr->ext_zfh || ctx->cfg_ptr->ext_zfhmin
> > ||          \
> >             ctx->cfg_ptr->ext_zhinx || ctx->cfg_ptr->ext_zhinxmin)) 
> > {     \
> >           return false;                                        \