[PATCH v1 4/6] xen/riscv: define pt_t and pt_walk_t structures

[Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>]

Refactor pte_t to be a union which hold page table entry plus
pt_t and pt_walk_t structures to simpilfy p2m functions.

Also, introduce some helpers which are using pt_walk_t.

Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
---
 xen/arch/riscv/include/asm/page.h | 54 ++++++++++++++++++++++++++++++-
 1 file changed, 53 insertions(+), 1 deletion(-)

diff --git a/xen/arch/riscv/include/asm/page.h 
b/xen/arch/riscv/include/asm/page.h
index 2af4823170..cb3dea309c 100644
--- a/xen/arch/riscv/include/asm/page.h
+++ b/xen/arch/riscv/include/asm/page.h
@@ -99,15 +99,67 @@
 
 #endif
 
-/* Page Table entry */
 typedef struct {
+    unsigned long v:1;
+    unsigned long r:1;
+    unsigned long w:1;
+    unsigned long x:1;
+    unsigned long u:1;
+    unsigned long g:1;
+    unsigned long a:1;
+    unsigned long d:1;
+    unsigned long rsw:2;
+#if RV_STAGE1_MODE == SATP_MODE_SV39
+    unsigned long ppn0:9;
+    unsigned long ppn1:9;
+    unsigned long ppn2:26;
+    unsigned long rsw2:7;
+    unsigned long pbmt:2;
+    unsigned long n:1;
+#elif RV_STAGE1_MODE == SATP_MODE_SV48
+    unsigned long ppn0:9;
+    unsigned long ppn1:9;
+    unsigned long ppn2:9;
+    unsigned long ppn3:17;
+    unsigned long rsw2:7;
+    unsigned long pbmt:2;
+    unsigned long n:1;
+#else
+#error "Add proper bits for SATP_MODE"
+#endif
+} pt_t;
+
+typedef struct {
+    unsigned long rsw:10;
+#if RV_STAGE1_MODE == SATP_MODE_SV39 || RV_STAGE1_MODE == SATP_MODE_SV48
+    unsigned long ppn: 44;
+#else
+#error "Add proper bits for SATP_MODE"
+#endif
+    unsigned long rsw2:10;
+} pt_walk_t;
+
+/* Page Table entry */
+typedef union {
 #ifdef CONFIG_RISCV_64
     uint64_t pte;
 #else
     uint32_t pte;
 #endif
+    pt_t bits;
+    pt_walk_t walk;
 } pte_t;
 
+static inline void pte_set_mfn(pte_t *pte, mfn_t mfn)
+{
+    pte->walk.ppn = mfn_x(mfn);
+}
+
+static inline mfn_t pte_get_mfn(pte_t pte)
+{
+    return _mfn(pte.walk.ppn);
+}
+
 static inline pte_t paddr_to_pte(paddr_t paddr,
                                  unsigned int permissions)
 {
-- 
2.49.0