[PULL,72/96] target/ppc/mmu_common.c: Simplify ppc6xx_tlb_pte_check()

Commit Message

Nicholas Piggin July 25, 2024, 11:53 p.m. UTC

From: BALATON Zoltan <[e-mail]>

Invert conditions to avoid deep nested ifs and return early instead.
Remove some obvious comments that don't add more clarity.

Signed-off-by: BALATON Zoltan <[e-mail]>
Reviewed-by: Nicholas Piggin <[e-mail]>
Signed-off-by: Nicholas Piggin <[e-mail]>
---
 target/ppc/mmu_common.c | 43 ++++++++++++++++++-----------------------
 1 file changed, 19 insertions(+), 24 deletions(-)

Patch

diff --git a/target/ppc/mmu_common.c b/target/ppc/mmu_common.c
index a5ae11394d..28adb3ca10 100644
--- a/target/ppc/mmu_common.c
+++ b/target/ppc/mmu_common.c
@@ -99,31 +99,26 @@  static int ppc6xx_tlb_pte_check(mmu_ctx_t *ctx, target_ulong pte0,
                                 MMUAccessType access_type)
 {
     /* Check validity and table match */
-    if (pte_is_valid(pte0) && ((pte0 >> 6) & 1) == pteh) {
-        /* Check vsid & api */
-        if ((pte0 & PTE_PTEM_MASK) == ctx->ptem) {
-            if (ctx->raddr != (hwaddr)-1ULL) {
-                /* all matches should have equal RPN, WIMG & PP */
-                if ((ctx->raddr & PTE_CHECK_MASK) != (pte1 & PTE_CHECK_MASK)) {
-                    qemu_log_mask(CPU_LOG_MMU, "Bad RPN/WIMG/PP\n");
-                    return -3;
-                }
-            }
-            /* Keep the matching PTE information */
-            ctx->raddr = pte1;
-            ctx->prot = ppc_hash32_prot(ctx->key, pte1 & HPTE32_R_PP, ctx->nx);
-            if (check_prot_access_type(ctx->prot, access_type)) {
-                /* Access granted */
-                qemu_log_mask(CPU_LOG_MMU, "PTE access granted !\n");
-                return 0;
-            } else {
-                /* Access right violation */
-                qemu_log_mask(CPU_LOG_MMU, "PTE access rejected\n");
-                return -2;
-            }
-        }
+    if (!pte_is_valid(pte0) || ((pte0 >> 6) & 1) != pteh ||
+        (pte0 & PTE_PTEM_MASK) != ctx->ptem) {
+        return -1;
+    }
+    /* all matches should have equal RPN, WIMG & PP */
+    if (ctx->raddr != (hwaddr)-1ULL &&
+        (ctx->raddr & PTE_CHECK_MASK) != (pte1 & PTE_CHECK_MASK)) {
+        qemu_log_mask(CPU_LOG_MMU, "Bad RPN/WIMG/PP\n");
+        return -3;
+    }
+    /* Keep the matching PTE information */
+    ctx->raddr = pte1;
+    ctx->prot = ppc_hash32_prot(ctx->key, pte1 & HPTE32_R_PP, ctx->nx);
+    if (check_prot_access_type(ctx->prot, access_type)) {
+        qemu_log_mask(CPU_LOG_MMU, "PTE access granted !\n");
+        return 0;
+    } else {
+        qemu_log_mask(CPU_LOG_MMU, "PTE access rejected\n");
+        return -2;
     }
-    return -1;
 }
 
 static int pte_update_flags(mmu_ctx_t *ctx, target_ulong *pte1p,