target/riscv: Merge checks for reserved pte flags

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Weiwei Li <liweiwei@iscas.ac.cn>
Tested-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Message-Id: <20230325105429.1142530-24-richard.henderson@linaro.org>
Message-Id: <20230412114333.118895-24-richard.henderson@linaro.org>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

target/riscv/cpu_helper.c

@@ -962,14 +962,14 @@ static int get_physical_address(CPURISCVState *env, hwaddr *physical,
         /* Reserved without Svpbmt. */
         return TRANSLATE_FAIL;
     }
-    if ((pte & (PTE_R | PTE_W | PTE_X)) == PTE_W) {
-        /* Reserved leaf PTE flags: PTE_W */
-        return TRANSLATE_FAIL;
-    }
-    if ((pte & (PTE_R | PTE_W | PTE_X)) == (PTE_W | PTE_X)) {
-        /* Reserved leaf PTE flags: PTE_W + PTE_X */
+
+    /* Check for reserved combinations of RWX flags. */
+    switch (pte & (PTE_R | PTE_W | PTE_X)) {
+    case PTE_W:
+    case PTE_W | PTE_X:
         return TRANSLATE_FAIL;
     }
+
     if ((pte & PTE_U) &&
         ((mode != PRV_U) && (!sum || access_type == MMU_INST_FETCH))) {
         /*