Re: [PATCH 3/3] target/loongarch: Remove unnecessary page size validity checking

[gaosong]

在 2025/6/18 下午2:26, Bibo Mao 写道:

Page size of TLB entry comes from CSR STLBPS and pwcl register. With
huge page, it is dir_base + dir_width from pwcl register. With normal
page, it is field of PTBASE from pwcl register.

So it is ok to check validity in function helper_ldpte() and function
helper_csrwr_stlbps(). And it is unnecessary in tlb entry fill path.

Signed-off-by: Bibo Mao <maob...@loongson.cn>
---
  target/loongarch/tcg/tlb_helper.c | 24 ++++++++----------------
  1 file changed, 8 insertions(+), 16 deletions(-)

Reviewed-by: Song Gao <gaos...@loongson.cn>

Thanks.
Song Gao

diff --git a/target/loongarch/tcg/tlb_helper.c 
b/target/loongarch/tcg/tlb_helper.c
index dc48b0f4d2..21381ba59f 100644
--- a/target/loongarch/tcg/tlb_helper.c
+++ b/target/loongarch/tcg/tlb_helper.c
@@ -173,12 +173,6 @@ static void fill_tlb_entry(CPULoongArchState *env, int 
index)
          lo1 = env->CSR_TLBELO1;
      }

- /*check csr_ps */

-    if (!check_ps(env, csr_ps)) {
-        qemu_log_mask(LOG_GUEST_ERROR, "csr_ps %d is illegal\n", csr_ps);
-        return;
-    }
-
      /* Only MTLB has the ps fields */
      if (index >= LOONGARCH_STLB) {
          tlb->tlb_misc = FIELD_DP64(tlb->tlb_misc, TLB_MISC, PS, csr_ps);
@@ -340,23 +334,16 @@ void helper_tlbfill(CPULoongArchState *env)

if (FIELD_EX64(env->CSR_TLBRERA, CSR_TLBRERA, ISTLBR)) {

          entryhi = env->CSR_TLBREHI;
+        /* Validity of pagesize is checked in helper_ldpte() */
          pagesize = FIELD_EX64(env->CSR_TLBREHI, CSR_TLBREHI, PS);
      } else {
          entryhi = env->CSR_TLBEHI;
+        /* Validity of pagesize is checked in helper_tlbrd() */
          pagesize = FIELD_EX64(env->CSR_TLBIDX, CSR_TLBIDX, PS);
      }

- if (!check_ps(env, pagesize)) {

-        qemu_log_mask(LOG_GUEST_ERROR, "pagesize %d is illegal\n", pagesize);
-        return;
-    }
-
+    /* Validity of stlb_ps is checked in helper_csrwr_stlbps() */
      stlb_ps = FIELD_EX64(env->CSR_STLBPS, CSR_STLBPS, PS);
-    if (!check_ps(env, stlb_ps)) {
-        qemu_log_mask(LOG_GUEST_ERROR, "stlb_ps %d is illegal\n", stlb_ps);
-        return;
-    }
-
      if (pagesize == stlb_ps) {
          /* Only write into STLB bits [47:13] */
          address = entryhi & ~MAKE_64BIT_MASK(0, R_CSR_TLBEHI_64_VPPN_SHIFT);
@@ -651,6 +638,11 @@ void helper_ldpte(CPULoongArchState *env, target_ulong 
base, target_ulong odd,
          if (odd) {
              tmp0 += MAKE_64BIT_MASK(ps, 1);
          }
+
+        if (!check_ps(env, ps)) {
+            qemu_log_mask(LOG_GUEST_ERROR, "Illegal huge pagesize %ld\n", ps);
+            return;
+        }
      } else {
          badv = env->CSR_TLBRBADV;