With software page table walker, tlb entry comes from CSR registers.
however with hardware page table walker, tlb entry comes from page
table entry information directly, TLB CSR registers are not necessary.

Here add function sptw_prepare_context(), get tlb entry information
from TLB CSR registers.

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Reviewed-by: Song Gao <gaosong@loongson.cn>
---
 target/loongarch/cpu-mmu.h        |  1 +
 target/loongarch/tcg/tlb_helper.c | 23 +++++++++++++++++++++--
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/target/loongarch/cpu-mmu.h b/target/loongarch/cpu-mmu.h
index 4ba82a7f81..aa43e57128 100644
--- a/target/loongarch/cpu-mmu.h
+++ b/target/loongarch/cpu-mmu.h
@@ -25,6 +25,7 @@ typedef struct MMUContext {
     hwaddr        physical;
     int           ps;  /* page size shift */
     int           prot;
+    uint64_t      pte_buddy[2];
 } MMUContext;
 
 static inline bool cpu_has_ptw(CPULoongArchState *env)
diff --git a/target/loongarch/tcg/tlb_helper.c b/target/loongarch/tcg/tlb_helper.c
index bc89a4d5ee..f42bbcde67 100644
--- a/target/loongarch/tcg/tlb_helper.c
+++ b/target/loongarch/tcg/tlb_helper.c
@@ -159,10 +159,10 @@ static void invalidate_tlb(CPULoongArchState *env, int index)
     invalidate_tlb_entry(env, index);
 }
 
-static void fill_tlb_entry(CPULoongArchState *env, LoongArchTLB *tlb)
+/* Prepare tlb entry information in software PTW mode */
+static void sptw_prepare_context(CPULoongArchState *env, MMUContext *context)
 {
     uint64_t lo0, lo1, csr_vppn;
-    uint16_t csr_asid;
     uint8_t csr_ps;
 
     if (FIELD_EX64(env->CSR_TLBRERA, CSR_TLBRERA, ISTLBR)) {
@@ -185,6 +185,25 @@ static void fill_tlb_entry(CPULoongArchState *env, LoongArchTLB *tlb)
         lo1 = env->CSR_TLBELO1;
     }
 
+    context->ps = csr_ps;
+    context->addr = csr_vppn << R_TLB_MISC_VPPN_SHIFT;
+    context->pte_buddy[0] = lo0;
+    context->pte_buddy[1] = lo1;
+}
+
+static void fill_tlb_entry(CPULoongArchState *env, LoongArchTLB *tlb)
+{
+    uint64_t lo0, lo1, csr_vppn;
+    uint16_t csr_asid;
+    uint8_t csr_ps;
+    MMUContext context;
+
+    sptw_prepare_context(env, &context);
+    csr_vppn = context.addr >> R_TLB_MISC_VPPN_SHIFT;
+    csr_ps   = context.ps;
+    lo0      = context.pte_buddy[0];
+    lo1      = context.pte_buddy[1];
+
     /* Store page size in field PS */
     tlb->tlb_misc = FIELD_DP64(tlb->tlb_misc, TLB_MISC, PS, csr_ps);
     tlb->tlb_misc = FIELD_DP64(tlb->tlb_misc, TLB_MISC, VPPN, csr_vppn);
-- 
2.43.5