[PATCH 0/2] Set MISA.[C|X] based on the selected extensions

[PATCH 0/2] Set MISA.[C|X] based on the selected extensions

[frank.chang]

From: Frank Chang <frank.chang@sifive.com>

MISA.C and MISA.X should be set when the following extensions are
selected:

MISA.C:
  * Zca and not F.
  * Zca, Zcf and F (but not D) is specified (RV32 only).
  * Zca, Zcf and Zcd if D is specified (RV32 only).
  * Zca, Zcd if D is specified (RV64 only)

MISA.X:
  * When there are any non-standard extensions enabled.

This patchset sets MISA.[C|X] bits based on the selected extensions.

Frank Chang (2):
  target/riscv: Update MISA.C for Zc* extensions
  target/riscv: Update MISA.X for non-standard extensions

 target/riscv/cpu.h         |  1 +
 target/riscv/tcg/tcg-cpu.c | 46 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 47 insertions(+)

--
2.43.0

[PATCH 1/2] target/riscv: Update MISA.C for Zc* extensions

[frank.chang]

From: Frank Chang <frank.chang@sifive.com>

MISA.C is set if the following extensions are selected:
  * Zca and not F.
  * Zca, Zcf and F (but not D) is specified (RV32 only).
  * Zca, Zcf and Zcd if D is specified (RV32 only).
  * Zca, Zcd if D is specified (RV64 only).

Therefore, we need to set MISA.C according to the rules for Zc*
extensions.

Signed-off-by: Frank Chang <frank.chang@sifive.com>
Reviewed-by: Max Chou <max.chou@sifive.com>
---
 target/riscv/tcg/tcg-cpu.c | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/target/riscv/tcg/tcg-cpu.c b/target/riscv/tcg/tcg-cpu.c
index 440626ddfad..da09a2417cc 100644
--- a/target/riscv/tcg/tcg-cpu.c
+++ b/target/riscv/tcg/tcg-cpu.c
@@ -1150,6 +1150,36 @@ static void riscv_cpu_enable_implied_rules(RISCVCPU *cpu)
     }
 }
 
+/*
+ * MISA.C is set if the following extensions are selected:
+ *   - Zca and not F.
+ *   - Zca, Zcf and F (but not D) is specified on RV32.
+ *   - Zca, Zcf and Zcd if D is specified on RV32.
+ *   - Zca, Zcd if D is specified on RV64.
+ */
+static void riscv_cpu_update_misa_c(RISCVCPU *cpu)
+{
+    CPURISCVState *env = &cpu->env;
+
+    if (cpu->cfg.ext_zca && !riscv_has_ext(env, RVF)) {
+        riscv_cpu_set_misa_ext(env, env->misa_ext | RVC);
+        return;
+    }
+
+    if (riscv_cpu_mxl(env) == MXL_RV32 &&
+        cpu->cfg.ext_zca && cpu->cfg.ext_zcf &&
+        riscv_has_ext(env, RVD) ? cpu->cfg.ext_zcd : riscv_has_ext(env, RVF)) {
+        riscv_cpu_set_misa_ext(env, env->misa_ext | RVC);
+        return;
+    }
+
+    if (riscv_cpu_mxl(env) == MXL_RV64 &&
+        cpu->cfg.ext_zca && cpu->cfg.ext_zcd) {
+        riscv_cpu_set_misa_ext(env, env->misa_ext | RVC);
+        return;
+    }
+}
+
 void riscv_tcg_cpu_finalize_features(RISCVCPU *cpu, Error **errp)
 {
     CPURISCVState *env = &cpu->env;
@@ -1157,6 +1187,7 @@ void riscv_tcg_cpu_finalize_features(RISCVCPU *cpu, Error **errp)
 
     riscv_cpu_init_implied_exts_rules();
     riscv_cpu_enable_implied_rules(cpu);
+    riscv_cpu_update_misa_c(cpu);
 
     riscv_cpu_validate_misa_priv(env, &local_err);
     if (local_err != NULL) {
-- 
2.43.0

Re: [PATCH 1/2] target/riscv: Update MISA.C for Zc* extensions

[Daniel Henrique Barboza]

On 11/14/25 6:01 AM, frank.chang@sifive.com wrote:
> From: Frank Chang <frank.chang@sifive.com>
> 
> MISA.C is set if the following extensions are selected:
>    * Zca and not F.
>    * Zca, Zcf and F (but not D) is specified (RV32 only).
>    * Zca, Zcf and Zcd if D is specified (RV32 only).
>    * Zca, Zcd if D is specified (RV64 only).
> 
> Therefore, we need to set MISA.C according to the rules for Zc*
> extensions.
> 
> Signed-off-by: Frank Chang <frank.chang@sifive.com>
> Reviewed-by: Max Chou <max.chou@sifive.com>
> ---

Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>

>   target/riscv/tcg/tcg-cpu.c | 31 +++++++++++++++++++++++++++++++
>   1 file changed, 31 insertions(+)
> 
> diff --git a/target/riscv/tcg/tcg-cpu.c b/target/riscv/tcg/tcg-cpu.c
> index 440626ddfad..da09a2417cc 100644
> --- a/target/riscv/tcg/tcg-cpu.c
> +++ b/target/riscv/tcg/tcg-cpu.c
> @@ -1150,6 +1150,36 @@ static void riscv_cpu_enable_implied_rules(RISCVCPU *cpu)
>       }
>   }
>   
> +/*
> + * MISA.C is set if the following extensions are selected:
> + *   - Zca and not F.
> + *   - Zca, Zcf and F (but not D) is specified on RV32.
> + *   - Zca, Zcf and Zcd if D is specified on RV32.
> + *   - Zca, Zcd if D is specified on RV64.
> + */
> +static void riscv_cpu_update_misa_c(RISCVCPU *cpu)
> +{
> +    CPURISCVState *env = &cpu->env;
> +
> +    if (cpu->cfg.ext_zca && !riscv_has_ext(env, RVF)) {
> +        riscv_cpu_set_misa_ext(env, env->misa_ext | RVC);
> +        return;
> +    }
> +
> +    if (riscv_cpu_mxl(env) == MXL_RV32 &&
> +        cpu->cfg.ext_zca && cpu->cfg.ext_zcf &&
> +        riscv_has_ext(env, RVD) ? cpu->cfg.ext_zcd : riscv_has_ext(env, RVF)) {
> +        riscv_cpu_set_misa_ext(env, env->misa_ext | RVC);
> +        return;
> +    }
> +
> +    if (riscv_cpu_mxl(env) == MXL_RV64 &&
> +        cpu->cfg.ext_zca && cpu->cfg.ext_zcd) {
> +        riscv_cpu_set_misa_ext(env, env->misa_ext | RVC);
> +        return;
> +    }
> +}
> +
>   void riscv_tcg_cpu_finalize_features(RISCVCPU *cpu, Error **errp)
>   {
>       CPURISCVState *env = &cpu->env;
> @@ -1157,6 +1187,7 @@ void riscv_tcg_cpu_finalize_features(RISCVCPU *cpu, Error **errp)
>   
>       riscv_cpu_init_implied_exts_rules();
>       riscv_cpu_enable_implied_rules(cpu);
> +    riscv_cpu_update_misa_c(cpu);
>   
>       riscv_cpu_validate_misa_priv(env, &local_err);
>       if (local_err != NULL) {

[PATCH 2/2] target/riscv: Update MISA.X for non-standard extensions

[frank.chang]

From: Frank Chang <frank.chang@sifive.com>

MISA.X is set if there are any non-standard extensions.
We should set MISA.X when any of the vendor extensions is enabled.

Signed-off-by: Frank Chang <frank.chang@sifive.com>
Reviewed-by: Max Chou <max.chou@sifive.com>
---
 target/riscv/cpu.h         |  1 +
 target/riscv/tcg/tcg-cpu.c | 15 +++++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index 8899bf7667a..2e0c92fe593 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -69,6 +69,7 @@ typedef struct CPUArchState CPURISCVState;
 #define RVH RV('H')
 #define RVG RV('G')
 #define RVB RV('B')
+#define RVX RV('X')
 
 extern const uint32_t misa_bits[];
 const char *riscv_get_misa_ext_name(uint32_t bit);
diff --git a/target/riscv/tcg/tcg-cpu.c b/target/riscv/tcg/tcg-cpu.c
index da09a2417cc..0d730f4d774 100644
--- a/target/riscv/tcg/tcg-cpu.c
+++ b/target/riscv/tcg/tcg-cpu.c
@@ -1180,6 +1180,20 @@ static void riscv_cpu_update_misa_c(RISCVCPU *cpu)
     }
 }
 
+/* MISA.X is set when any of the non-standard extensions is enabled. */
+static void riscv_cpu_update_misa_x(RISCVCPU *cpu)
+{
+    CPURISCVState *env = &cpu->env;
+    const RISCVCPUMultiExtConfig *arr = riscv_cpu_vendor_exts;
+
+    for (int i = 0; arr[i].name != NULL; i++) {
+        if (isa_ext_is_enabled(cpu, arr[i].offset)) {
+            riscv_cpu_set_misa_ext(env, env->misa_ext | RVX);
+            break;
+        }
+    }
+}
+
 void riscv_tcg_cpu_finalize_features(RISCVCPU *cpu, Error **errp)
 {
     CPURISCVState *env = &cpu->env;
@@ -1188,6 +1202,7 @@ void riscv_tcg_cpu_finalize_features(RISCVCPU *cpu, Error **errp)
     riscv_cpu_init_implied_exts_rules();
     riscv_cpu_enable_implied_rules(cpu);
     riscv_cpu_update_misa_c(cpu);
+    riscv_cpu_update_misa_x(cpu);
 
     riscv_cpu_validate_misa_priv(env, &local_err);
     if (local_err != NULL) {
-- 
2.43.0

Re: [PATCH 2/2] target/riscv: Update MISA.X for non-standard extensions

[Daniel Henrique Barboza]

On 11/14/25 6:01 AM, frank.chang@sifive.com wrote:
> From: Frank Chang <frank.chang@sifive.com>
> 
> MISA.X is set if there are any non-standard extensions.
> We should set MISA.X when any of the vendor extensions is enabled.
> 
> Signed-off-by: Frank Chang <frank.chang@sifive.com>
> Reviewed-by: Max Chou <max.chou@sifive.com>
> ---

Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>

>   target/riscv/cpu.h         |  1 +
>   target/riscv/tcg/tcg-cpu.c | 15 +++++++++++++++
>   2 files changed, 16 insertions(+)
> 
> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> index 8899bf7667a..2e0c92fe593 100644
> --- a/target/riscv/cpu.h
> +++ b/target/riscv/cpu.h
> @@ -69,6 +69,7 @@ typedef struct CPUArchState CPURISCVState;
>   #define RVH RV('H')
>   #define RVG RV('G')
>   #define RVB RV('B')
> +#define RVX RV('X')
>   
>   extern const uint32_t misa_bits[];
>   const char *riscv_get_misa_ext_name(uint32_t bit);
> diff --git a/target/riscv/tcg/tcg-cpu.c b/target/riscv/tcg/tcg-cpu.c
> index da09a2417cc..0d730f4d774 100644
> --- a/target/riscv/tcg/tcg-cpu.c
> +++ b/target/riscv/tcg/tcg-cpu.c
> @@ -1180,6 +1180,20 @@ static void riscv_cpu_update_misa_c(RISCVCPU *cpu)
>       }
>   }
>   
> +/* MISA.X is set when any of the non-standard extensions is enabled. */
> +static void riscv_cpu_update_misa_x(RISCVCPU *cpu)
> +{
> +    CPURISCVState *env = &cpu->env;
> +    const RISCVCPUMultiExtConfig *arr = riscv_cpu_vendor_exts;
> +
> +    for (int i = 0; arr[i].name != NULL; i++) {
> +        if (isa_ext_is_enabled(cpu, arr[i].offset)) {
> +            riscv_cpu_set_misa_ext(env, env->misa_ext | RVX);
> +            break;
> +        }
> +    }
> +}
> +
>   void riscv_tcg_cpu_finalize_features(RISCVCPU *cpu, Error **errp)
>   {
>       CPURISCVState *env = &cpu->env;
> @@ -1188,6 +1202,7 @@ void riscv_tcg_cpu_finalize_features(RISCVCPU *cpu, Error **errp)
>       riscv_cpu_init_implied_exts_rules();
>       riscv_cpu_enable_implied_rules(cpu);
>       riscv_cpu_update_misa_c(cpu);
> +    riscv_cpu_update_misa_x(cpu);
>   
>       riscv_cpu_validate_misa_priv(env, &local_err);
>       if (local_err != NULL) {