target/riscv: rvv-1.0: Add Zve64f extension into RISC-V

Signed-off-by: Frank Chang <frank.chang@sifive.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20220118014522.13613-2-frank.chang@sifive.com
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

target/riscv/cpu.c

@@ -609,6 +609,10 @@ static void riscv_cpu_realize(DeviceState *dev, Error **errp)
             }
             set_vext_version(env, vext_version);
         }
+        if (cpu->cfg.ext_zve64f && !cpu->cfg.ext_f) {
+            error_setg(errp, "Zve64f extension depends upon RVF.");
+            return;
+        }
         if (cpu->cfg.ext_j) {
             ext |= RVJ;
         }