[PATCH 4/4] Add a config option for ePMP.

[Hou Weiying]

Add a config option to enable experimental support for ePMP. This
is disabled by default and can be enabled with 'x-epmp=true'.

Signed-off-by: Hongzheng-Li <Ethan.Lee.QNL@gmail.com>
Signed-off-by: Hou Weiying <weiying_hou@outlook.com>
Signed-off-by: Myriad-Dreamin <camiyoru@gmail.com>
---
 target/riscv/cpu.c | 9 +++++++++
 target/riscv/cpu.h | 3 +++
 2 files changed, 12 insertions(+)

diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index 059d71f2c7..79fa9d3c2f 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -407,6 +407,14 @@ static void riscv_cpu_realize(DeviceState *dev, Error 
**errp)
 
     if (cpu->cfg.pmp) {
         set_feature(env, RISCV_FEATURE_PMP);
+
+        /*
+         * Enhanced PMP should only be available
+         * on harts with PMP support
+         */
+        if (cpu->cfg.epmp) {
+            set_feature(env, RISCV_FEATURE_EPMP);
+        }
     }
 
     /* If misa isn't set (rv32 and rv64 machines) set it here */
@@ -509,6 +517,7 @@ static Property riscv_cpu_properties[] = {
     DEFINE_PROP_STRING("priv_spec", RISCVCPU, cfg.priv_spec),
     DEFINE_PROP_BOOL("mmu", RISCVCPU, cfg.mmu, true),
     DEFINE_PROP_BOOL("pmp", RISCVCPU, cfg.pmp, true),
+    DEFINE_PROP_BOOL("x-epmp", RISCVCPU, cfg.epmp, false),
     DEFINE_PROP_END_OF_LIST(),
 };
 
diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index d0e7f5b9c5..afdc9fa2bf 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -77,6 +77,7 @@
 enum {
     RISCV_FEATURE_MMU,
     RISCV_FEATURE_PMP,
+    RISCV_FEATURE_EPMP,
     RISCV_FEATURE_MISA
 };
 
@@ -202,6 +203,7 @@ struct CPURISCVState {
 
     /* physical memory protection */
     pmp_table_t pmp_state;
+    target_ulong mseccfg;
 
     /* machine specific rdtime callback */
     uint64_t (*rdtime_fn)(void);
@@ -272,6 +274,7 @@ typedef struct RISCVCPU {
         char *user_spec;
         bool mmu;
         bool pmp;
+        bool epmp;
     } cfg;
 } RISCVCPU;
 
-- 
2.20.1