[PATCH v2 2/6] target/riscv: Add a helper to return the current effective priv mode

[frank . chang]

From: Frank Chang <frank.ch...@sifive.com>

This helper returns the current effective privilege mode.

Signed-off-by: Frank Chang <frank.ch...@sifive.com>
---
 target/riscv/cpu.h        |  1 +
 target/riscv/cpu_helper.c | 55 ++++++++++++++++++++++++++++++++-------
 2 files changed, 46 insertions(+), 10 deletions(-)

diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index 8899bf7667a..ab285d7a6d1 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -607,6 +607,7 @@ target_ulong riscv_cpu_get_geilen(CPURISCVState *env);
 void riscv_cpu_set_geilen(CPURISCVState *env, target_ulong geilen);
 bool riscv_cpu_vector_enabled(CPURISCVState *env);
 void riscv_cpu_set_virt_enabled(CPURISCVState *env, bool enable);
+bool riscv_cpu_eff_priv(CPURISCVState *env, int *priv, bool *virt);
 int riscv_env_mmu_index(CPURISCVState *env, bool ifetch);
 bool cpu_get_fcfien(CPURISCVState *env);
 bool cpu_get_bcfien(CPURISCVState *env);
diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
index dd6c861a90e..fbab8177092 100644
--- a/target/riscv/cpu_helper.c
+++ b/target/riscv/cpu_helper.c
@@ -38,6 +38,46 @@
 #include "pmp.h"
 #include "qemu/plugin.h"
 
+/*
+ * Returns the current effective privilege mode.
+ *
+ * @env: CPURISCVState
+ * @priv: The returned effective privilege mode.
+ * @virt: The returned effective virtualization mode.
+ *
+ * Returns true if the effective privilege mode is modified.
+ */
+bool riscv_cpu_eff_priv(CPURISCVState *env, int *priv, bool *virt)
+{
+#ifndef CONFIG_USER_ONLY
+    int mode = env->priv;
+    bool virt_enabled = env->virt_enabled;
+    bool mode_modified = false;
+
+#ifndef CONFIG_USER_ONLY
+    if (mode == PRV_M && get_field(env->mstatus, MSTATUS_MPRV)) {
+        mode = get_field(env->mstatus, MSTATUS_MPP);
+        virt_enabled = get_field(env->mstatus, MSTATUS_MPV) && (mode != PRV_M);
+        mode_modified = true;
+    }
+#endif
+
+    if (priv) {
+        *priv = mode;
+    }
+
+    if (virt) {
+        *virt = virt_enabled;
+    }
+
+    return mode_modified;
+#else
+    *priv = env->priv;
+    *virt = false;
+    return false;
+#endif
+}
+
 int riscv_env_mmu_index(CPURISCVState *env, bool ifetch)
 {
 #ifdef CONFIG_USER_ONLY
@@ -45,19 +85,14 @@ int riscv_env_mmu_index(CPURISCVState *env, bool ifetch)
 #else
     bool virt = env->virt_enabled;
     int mode = env->priv;
+    bool mode_modified = false;
 
     /* All priv -> mmu_idx mapping are here */
     if (!ifetch) {
-        uint64_t status = env->mstatus;
-
-        if (mode == PRV_M && get_field(status, MSTATUS_MPRV)) {
-            mode = get_field(env->mstatus, MSTATUS_MPP);
-            virt = get_field(env->mstatus, MSTATUS_MPV) &&
-                   (mode != PRV_M);
-            if (virt) {
-                status = env->vsstatus;
-            }
-        }
+        mode_modified = riscv_cpu_eff_priv(env, &mode, &virt);
+        uint64_t status = (mode_modified && virt) ? env->vsstatus :
+                                                    env->mstatus;
+
         if (mode == PRV_S && get_field(status, MSTATUS_SUM)) {
             mode = MMUIdx_S_SUM;
         }
-- 
2.43.0