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 752eee32289..61d7666288e 100644
--- a/target/riscv/tcg/tcg-cpu.c
+++ b/target/riscv/tcg/tcg-cpu.c
@@ -1181,6 +1181,20 @@ 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;
@@ -1189,6 +1203,7 @@ 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