[RFC PATCH 3/3] target/riscv: add support for svpbmt extension

[liweiwei]

It uses two PTE bits, but QEMU is sequentially consistent, So it has no effect 
on QEMU currently.

Signed-off-by: liweiwei <liweiwei@iscas.ac.cn>
Signed-off-by: wangjunqiang <wangjunqiang@iscas.ac.cn>
---
 target/riscv/cpu_bits.h   | 4 ++++
 target/riscv/cpu_helper.c | 9 +++++++--
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
index 70391424b0..62713ec37a 100644
--- a/target/riscv/cpu_bits.h
+++ b/target/riscv/cpu_bits.h
@@ -473,7 +473,11 @@ typedef enum {
 #define PTE_A               0x040 /* Accessed */
 #define PTE_D               0x080 /* Dirty */
 #define PTE_SOFT            0x300 /* Reserved for Software */
+#define PTE_RSVD            0x1FC0000000000000 /* Reserved for future use */
+#define PTE_PBMT            0x6000000000000000 /* Page-based memory types */
 #define PTE_N               0x8000000000000000
+#define PTE_ATTR            0xFFC0000000000000 /* All attributes bits */
+
 
 /* Page table PPN shift amount */
 #define PTE_PPN_SHIFT       10
diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
index e68db3e119..94b01bbf78 100644
--- a/target/riscv/cpu_helper.c
+++ b/target/riscv/cpu_helper.c
@@ -588,13 +588,18 @@ restart:
             return TRANSLATE_FAIL;
         }
 
-        hwaddr ppn = (pte & ~(target_ulong)PTE_N) >> PTE_PPN_SHIFT;
+        hwaddr ppn = (pte & ~(target_ulong)PTE_ATTR) >> PTE_PPN_SHIFT;
 
-        if (!(pte & PTE_V)) {
+        if (pte & PTE_RSVD) {
+            return TRANSLATE_FAIL;
+        } else if (!(pte & PTE_V)) {
             /* Invalid PTE */
             return TRANSLATE_FAIL;
         } else if (!(pte & (PTE_R | PTE_W | PTE_X))) {
             /* Inner PTE, continue walking */
+            if (pte & (PTE_D | PTE_A | PTE_U | PTE_N | PTE_PBMT)) {
+                return TRANSLATE_FAIL;
+            }
             base = ppn << PGSHIFT;
         } else if ((pte & (PTE_R | PTE_W | PTE_X)) == PTE_W) {
             /* Reserved leaf PTE flags: PTE_W */
-- 
2.17.1