target/riscv: Reuse tb->flags.FS

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>
Message-Id: <20230518175058.2772506-3-mchitale@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

target/riscv/cpu_helper.c

@@ -120,6 +120,12 @@ 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);
     }

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 {\