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* [PATCH 1/6] target/ppc: Fix 440 tlbwe TLB invalidation gaps
@ 2024-01-17 15:12 Nicholas Piggin
  2024-01-17 15:12 ` [PATCH 2/6] target/ppc: Factor out 4xx ppcemb_tlb_t flushing Nicholas Piggin
                   ` (6 more replies)
  0 siblings, 7 replies; 13+ messages in thread
From: Nicholas Piggin @ 2024-01-17 15:12 UTC (permalink / raw)
  To: qemu-ppc
  Cc: Nicholas Piggin, Daniel Henrique Barboza, Cédric Le Goater,
	Harsh Prateek Bora, BALATON Zoltan, qemu-devel

The 440 software TLB write entry misses several cases that must flush
the TCG TLB:
- If the new size is smaller than the existing size, the EA no longer
  covered should be flushed. This looks like an inverted inequality test.
- If the TLB PID changes.
- If the TLB attr bit 0 (translation address space) changes.
- If low prot (access control) bits change.

Fix this by removing tricks to avoid TLB flushes, and just invalidate
the TLB if any valid entry is being changed, similarly to 4xx.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 target/ppc/mmu_helper.c | 35 ++++++++++-------------------------
 1 file changed, 10 insertions(+), 25 deletions(-)

diff --git a/target/ppc/mmu_helper.c b/target/ppc/mmu_helper.c
index f87d35379a..c140f3c96d 100644
--- a/target/ppc/mmu_helper.c
+++ b/target/ppc/mmu_helper.c
@@ -855,49 +855,34 @@ void helper_440_tlbwe(CPUPPCState *env, uint32_t word, target_ulong entry,
                       target_ulong value)
 {
     ppcemb_tlb_t *tlb;
-    target_ulong EPN, RPN, size;
-    int do_flush_tlbs;
 
     qemu_log_mask(CPU_LOG_MMU, "%s word %d entry %d value " TARGET_FMT_lx "\n",
                   __func__, word, (int)entry, value);
-    do_flush_tlbs = 0;
     entry &= 0x3F;
     tlb = &env->tlb.tlbe[entry];
+
+    /* Invalidate previous TLB (if it's valid) */
+    if (tlb->prot & PAGE_VALID) {
+        tlb_flush(env_cpu(env));
+    }
+
     switch (word) {
     default:
         /* Just here to please gcc */
     case 0:
-        EPN = value & 0xFFFFFC00;
-        if ((tlb->prot & PAGE_VALID) && EPN != tlb->EPN) {
-            do_flush_tlbs = 1;
-        }
-        tlb->EPN = EPN;
-        size = booke_tlb_to_page_size((value >> 4) & 0xF);
-        if ((tlb->prot & PAGE_VALID) && tlb->size < size) {
-            do_flush_tlbs = 1;
-        }
-        tlb->size = size;
+        tlb->EPN = value & 0xFFFFFC00;
+        tlb->size = booke_tlb_to_page_size((value >> 4) & 0xF);
         tlb->attr &= ~0x1;
         tlb->attr |= (value >> 8) & 1;
         if (value & 0x200) {
             tlb->prot |= PAGE_VALID;
         } else {
-            if (tlb->prot & PAGE_VALID) {
-                tlb->prot &= ~PAGE_VALID;
-                do_flush_tlbs = 1;
-            }
+            tlb->prot &= ~PAGE_VALID;
         }
         tlb->PID = env->spr[SPR_440_MMUCR] & 0x000000FF;
-        if (do_flush_tlbs) {
-            tlb_flush(env_cpu(env));
-        }
         break;
     case 1:
-        RPN = value & 0xFFFFFC0F;
-        if ((tlb->prot & PAGE_VALID) && tlb->RPN != RPN) {
-            tlb_flush(env_cpu(env));
-        }
-        tlb->RPN = RPN;
+        tlb->RPN = value & 0xFFFFFC0F;
         break;
     case 2:
         tlb->attr = (tlb->attr & 0x1) | (value & 0x0000FF00);
-- 
2.42.0



^ permalink raw reply related	[flat|nested] 13+ messages in thread

end of thread, other threads:[~2024-02-16 13:29 UTC | newest]

Thread overview: 13+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2024-01-17 15:12 [PATCH 1/6] target/ppc: Fix 440 tlbwe TLB invalidation gaps Nicholas Piggin
2024-01-17 15:12 ` [PATCH 2/6] target/ppc: Factor out 4xx ppcemb_tlb_t flushing Nicholas Piggin
2024-01-25 10:39   ` Cédric Le Goater
2024-01-17 15:12 ` [PATCH 3/6] target/ppc: 4xx don't flush TLB for a newly written software TLB entry Nicholas Piggin
2024-01-25 10:44   ` Cédric Le Goater
2024-01-17 15:12 ` [PATCH 4/6] target/ppc: 4xx optimise tlbwe_lo TLB flushing Nicholas Piggin
2024-01-25 10:44   ` Cédric Le Goater
2024-01-17 15:12 ` [PATCH 5/6] target/ppc: 440 optimise tlbwe " Nicholas Piggin
2024-01-25 10:44   ` Cédric Le Goater
2024-01-17 15:12 ` [PATCH 6/6] target/ppc: optimise ppcemb_tlb_t flushing Nicholas Piggin
2024-01-25 10:45   ` Cédric Le Goater
2024-01-25 10:38 ` [PATCH 1/6] target/ppc: Fix 440 tlbwe TLB invalidation gaps Cédric Le Goater
2024-02-16 13:28 ` BALATON Zoltan

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