[PATCH v5 0/3] Smstateen FCSR

[PATCH v5 0/3] Smstateen FCSR

[Mayuresh Chitale]

Patch 4 and 5 of the smstateen series need to be re-submitted with
changes described in the email below.
https://lists.nongnu.org/archive/html/qemu-riscv/2022-11/msg00155.html
Hence splitting the patch 4 of the original series into three and
re-submitting along with the original patch 5.

Changes in v5:
- Ammend patch 1 commit message
- Add reviewed-by tag

Changes in v4:
- Drop patch 3 
- Add reviewed-by tag

Changes in v3:
- Reuse TB_FLAGS.FS (instead of TB_FLAGS.HS_FS) for smstateen as HS_FS bits been removed.
- Remove fcsr check for zfh and zfhmin

Changes in v2:
 - Improve patch 1 description
 - Reuse TB_FLAGS.HS_FS for smstateen
 - Convert smstateen_fcsr_check to function
 - Add fcsr check for zdinx

Mayuresh Chitale (3):
  target/riscv: smstateen check for fcsr
  target/riscv: Reuse tb->flags.FS
  target/riscv: smstateen knobs

 target/riscv/cpu.c                      |  3 ++-
 target/riscv/cpu_helper.c               |  6 ++++++
 target/riscv/csr.c                      | 15 +++++++++++++++
 target/riscv/insn_trans/trans_rvf.c.inc |  7 ++++---
 4 files changed, 27 insertions(+), 4 deletions(-)

-- 
2.34.1

[PATCH v5 1/3] target/riscv: smstateen check for fcsr

[Mayuresh Chitale]

Implement the s/h/mstateen.fcsr bit as defined in the smstateen spec
and check for it when accessing the fcsr register and its fields.

Signed-off-by: Mayuresh Chitale <mchitale@ventanamicro.com>
Reviewed-by: Weiwei Li <liweiwei@iscas.ac.cn>
---
 target/riscv/csr.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index 4451bd1263..3f6b824bd2 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -82,6 +82,10 @@ static RISCVException fs(CPURISCVState *env, int csrno)
         !riscv_cpu_cfg(env)->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;
 }
@@ -2100,6 +2104,9 @@ 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);
 }
@@ -2173,6 +2180,10 @@ 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);
 }
 
@@ -2259,6 +2270,10 @@ 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);
 }
 
-- 
2.34.1

Re: [PATCH v5 1/3] target/riscv: smstateen check for fcsr

[Alistair Francis]

On Fri, May 19, 2023 at 3:51 AM Mayuresh Chitale
<mchitale@ventanamicro.com> wrote:
>
> Implement the s/h/mstateen.fcsr bit as defined in the smstateen spec
> and check for it when accessing the fcsr register and its fields.
>
> Signed-off-by: Mayuresh Chitale <mchitale@ventanamicro.com>
> Reviewed-by: Weiwei Li <liweiwei@iscas.ac.cn>

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

Alistair

> ---
>  target/riscv/csr.c | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
>
> diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> index 4451bd1263..3f6b824bd2 100644
> --- a/target/riscv/csr.c
> +++ b/target/riscv/csr.c
> @@ -82,6 +82,10 @@ static RISCVException fs(CPURISCVState *env, int csrno)
>          !riscv_cpu_cfg(env)->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;
>  }
> @@ -2100,6 +2104,9 @@ 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);
>  }
> @@ -2173,6 +2180,10 @@ 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);
>  }
>
> @@ -2259,6 +2270,10 @@ 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);
>  }
>
> --
> 2.34.1
>

[PATCH v5 2/3] target/riscv: Reuse tb->flags.FS

[Mayuresh Chitale]

When misa.F is 0 tb->flags.FS field is unused and can be used to save
the current state of smstateen0.FCSR check which is needed by the
floating point translation routines.

Signed-off-by: Mayuresh Chitale <mchitale@ventanamicro.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Weiwei Li <liweiwei@iscas.ac.cn>
---
 target/riscv/cpu_helper.c               | 6 ++++++
 target/riscv/insn_trans/trans_rvf.c.inc | 7 ++++---
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
index b68dcfe7b6..695c189f96 100644
--- a/target/riscv/cpu_helper.c
+++ b/target/riscv/cpu_helper.c
@@ -119,6 +119,12 @@ void cpu_get_tb_cpu_state(CPURISCVState *env, target_ulong *pc,
         vs = MIN(vs, get_field(env->mstatus_hs, MSTATUS_VS));
     }
 
+    /* With Zfinx, floating point is enabled/disabled by Smstateen. */
+    if (!riscv_has_ext(env, RVF)) {
+        fs = (smstateen_acc_ok(env, 0, SMSTATEEN0_FCSR) == RISCV_EXCP_NONE)
+             ? EXT_STATUS_DIRTY : EXT_STATUS_DISABLED;
+    }
+
     if (cpu->cfg.debug && !icount_enabled()) {
         flags = FIELD_DP32(flags, TB_FLAGS, ITRIGGER, env->itrigger_enabled);
     }
diff --git a/target/riscv/insn_trans/trans_rvf.c.inc b/target/riscv/insn_trans/trans_rvf.c.inc
index b2de4fcf3f..509a6acffe 100644
--- a/target/riscv/insn_trans/trans_rvf.c.inc
+++ b/target/riscv/insn_trans/trans_rvf.c.inc
@@ -19,9 +19,10 @@
  */
 
 #define REQUIRE_FPU do {\
-    if (ctx->mstatus_fs == EXT_STATUS_DISABLED) \
-        if (!ctx->cfg_ptr->ext_zfinx) \
-            return false; \
+    if (ctx->mstatus_fs == EXT_STATUS_DISABLED) {                           \
+        ctx->virt_inst_excp = ctx->virt_enabled && ctx->cfg_ptr->ext_zfinx; \
+        return false;                                                       \
+    }                                                                       \
 } while (0)
 
 #define REQUIRE_ZFINX_OR_F(ctx) do {\
-- 
2.34.1

Re: [PATCH v5 2/3] target/riscv: Reuse tb->flags.FS

[Alistair Francis]

On Fri, May 19, 2023 at 3:51 AM Mayuresh Chitale
<mchitale@ventanamicro.com> wrote:
>
> When misa.F is 0 tb->flags.FS field is unused and can be used to save
> the current state of smstateen0.FCSR check which is needed by the
> floating point translation routines.
>
> Signed-off-by: Mayuresh Chitale <mchitale@ventanamicro.com>
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
> Reviewed-by: Weiwei Li <liweiwei@iscas.ac.cn>

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

Alistair

> ---
>  target/riscv/cpu_helper.c               | 6 ++++++
>  target/riscv/insn_trans/trans_rvf.c.inc | 7 ++++---
>  2 files changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
> index b68dcfe7b6..695c189f96 100644
> --- a/target/riscv/cpu_helper.c
> +++ b/target/riscv/cpu_helper.c
> @@ -119,6 +119,12 @@ void cpu_get_tb_cpu_state(CPURISCVState *env, target_ulong *pc,
>          vs = MIN(vs, get_field(env->mstatus_hs, MSTATUS_VS));
>      }
>
> +    /* With Zfinx, floating point is enabled/disabled by Smstateen. */
> +    if (!riscv_has_ext(env, RVF)) {
> +        fs = (smstateen_acc_ok(env, 0, SMSTATEEN0_FCSR) == RISCV_EXCP_NONE)
> +             ? EXT_STATUS_DIRTY : EXT_STATUS_DISABLED;
> +    }
> +
>      if (cpu->cfg.debug && !icount_enabled()) {
>          flags = FIELD_DP32(flags, TB_FLAGS, ITRIGGER, env->itrigger_enabled);
>      }
> diff --git a/target/riscv/insn_trans/trans_rvf.c.inc b/target/riscv/insn_trans/trans_rvf.c.inc
> index b2de4fcf3f..509a6acffe 100644
> --- a/target/riscv/insn_trans/trans_rvf.c.inc
> +++ b/target/riscv/insn_trans/trans_rvf.c.inc
> @@ -19,9 +19,10 @@
>   */
>
>  #define REQUIRE_FPU do {\
> -    if (ctx->mstatus_fs == EXT_STATUS_DISABLED) \
> -        if (!ctx->cfg_ptr->ext_zfinx) \
> -            return false; \
> +    if (ctx->mstatus_fs == EXT_STATUS_DISABLED) {                           \
> +        ctx->virt_inst_excp = ctx->virt_enabled && ctx->cfg_ptr->ext_zfinx; \
> +        return false;                                                       \
> +    }                                                                       \
>  } while (0)
>
>  #define REQUIRE_ZFINX_OR_F(ctx) do {\
> --
> 2.34.1
>

[PATCH v5 3/3] target/riscv: smstateen knobs

[Mayuresh Chitale]

Add knobs to allow users to enable smstateen and also export it via the
ISA extension string.

Signed-off-by: Mayuresh Chitale <mchitale@ventanamicro.com>
Reviewed-by: Weiwei Li<liweiwei@iscas.ac.cn>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
---
 target/riscv/cpu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index befa64528f..9420cd670e 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -119,6 +119,7 @@ static const struct isa_ext_data isa_edata_arr[] = {
     ISA_EXT_DATA_ENTRY(zhinx, PRIV_VERSION_1_12_0, ext_zhinx),
     ISA_EXT_DATA_ENTRY(zhinxmin, PRIV_VERSION_1_12_0, ext_zhinxmin),
     ISA_EXT_DATA_ENTRY(smaia, PRIV_VERSION_1_12_0, ext_smaia),
+    ISA_EXT_DATA_ENTRY(smstateen, PRIV_VERSION_1_12_0, ext_smstateen),
     ISA_EXT_DATA_ENTRY(ssaia, PRIV_VERSION_1_12_0, ext_ssaia),
     ISA_EXT_DATA_ENTRY(sscofpmf, PRIV_VERSION_1_12_0, ext_sscofpmf),
     ISA_EXT_DATA_ENTRY(sstc, PRIV_VERSION_1_12_0, ext_sstc),
@@ -1498,8 +1499,8 @@ static Property riscv_cpu_extensions[] = {
     DEFINE_PROP_UINT16("vlen", RISCVCPU, cfg.vlen, 128),
     DEFINE_PROP_UINT16("elen", RISCVCPU, cfg.elen, 64),
 
+    DEFINE_PROP_BOOL("smstateen", RISCVCPU, cfg.ext_smstateen, false),
     DEFINE_PROP_BOOL("svadu", RISCVCPU, cfg.ext_svadu, true),
-
     DEFINE_PROP_BOOL("svinval", RISCVCPU, cfg.ext_svinval, false),
     DEFINE_PROP_BOOL("svnapot", RISCVCPU, cfg.ext_svnapot, false),
     DEFINE_PROP_BOOL("svpbmt", RISCVCPU, cfg.ext_svpbmt, false),
-- 
2.34.1

Re: [PATCH v5 0/3] Smstateen FCSR

[Alistair Francis]

On Fri, May 19, 2023 at 3:51 AM Mayuresh Chitale
<mchitale@ventanamicro.com> wrote:
>
> Patch 4 and 5 of the smstateen series need to be re-submitted with
> changes described in the email below.
> https://lists.nongnu.org/archive/html/qemu-riscv/2022-11/msg00155.html
> Hence splitting the patch 4 of the original series into three and
> re-submitting along with the original patch 5.
>
> Changes in v5:
> - Ammend patch 1 commit message
> - Add reviewed-by tag
>
> Changes in v4:
> - Drop patch 3
> - Add reviewed-by tag
>
> Changes in v3:
> - Reuse TB_FLAGS.FS (instead of TB_FLAGS.HS_FS) for smstateen as HS_FS bits been removed.
> - Remove fcsr check for zfh and zfhmin
>
> Changes in v2:
>  - Improve patch 1 description
>  - Reuse TB_FLAGS.HS_FS for smstateen
>  - Convert smstateen_fcsr_check to function
>  - Add fcsr check for zdinx
>
> Mayuresh Chitale (3):
>   target/riscv: smstateen check for fcsr
>   target/riscv: Reuse tb->flags.FS
>   target/riscv: smstateen knobs

Thanks!

Applied to riscv-to-apply.next

Alistair

>
>  target/riscv/cpu.c                      |  3 ++-
>  target/riscv/cpu_helper.c               |  6 ++++++
>  target/riscv/csr.c                      | 15 +++++++++++++++
>  target/riscv/insn_trans/trans_rvf.c.inc |  7 ++++---
>  4 files changed, 27 insertions(+), 4 deletions(-)
>
> --
> 2.34.1
>