[PATCH v3 1/3] target/riscv: Fix the mstatus.MPP value after executing MRET

[Weiwei Li <liweiwei@iscas.ac.cn>]

The MPP will be set to the least-privileged supported mode (U if
U-mode is implemented, else M).

Signed-off-by: Weiwei Li <liweiwei@iscas.ac.cn>
Signed-off-by: Junqiang Wang <wangjunqiang@iscas.ac.cn>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
---
 target/riscv/op_helper.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/target/riscv/op_helper.c b/target/riscv/op_helper.c
index ec9a384772..b8a03afebb 100644
--- a/target/riscv/op_helper.c
+++ b/target/riscv/op_helper.c
@@ -338,7 +338,8 @@ target_ulong helper_mret(CPURISCVState *env)
     mstatus = set_field(mstatus, MSTATUS_MIE,
                         get_field(mstatus, MSTATUS_MPIE));
     mstatus = set_field(mstatus, MSTATUS_MPIE, 1);
-    mstatus = set_field(mstatus, MSTATUS_MPP, PRV_U);
+    mstatus = set_field(mstatus, MSTATUS_MPP,
+                        riscv_has_ext(env, RVU) ? PRV_U : PRV_M);
     mstatus = set_field(mstatus, MSTATUS_MPV, 0);
     if ((env->priv_ver >= PRIV_VERSION_1_12_0) && (prev_priv != PRV_M)) {
         mstatus = set_field(mstatus, MSTATUS_MPRV, 0);
-- 
2.25.1