From 5646d6a70fc24cf434582ccdd0c8840d79fe7cc8 Mon Sep 17 00:00:00 2001
From: Richard Henderson <richard.henderson@linaro.org>
Date: Sun, 27 Aug 2023 11:25:25 -0700
Subject: [PATCH] accel/tcg: Merge io_writex into do_st_mmio_leN

Avoid multiple calls to io_prepare for unaligned acceses.
One call to do_st_mmio_leN will never cross pages.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 accel/tcg/cputlb.c | 80 +++++++++++++++++-----------------------------
 1 file changed, 29 insertions(+), 51 deletions(-)

diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c
index 6cf69bd79d..1d56e3ec0c 100644
--- a/accel/tcg/cputlb.c
+++ b/accel/tcg/cputlb.c
@@ -1388,30 +1388,6 @@ static void io_failed(CPUArchState *env, CPUTLBEntryFull *full, vaddr addr,
     }
 }
 
-static void io_writex(CPUArchState *env, CPUTLBEntryFull *full,
-                      int mmu_idx, uint64_t val, vaddr addr,
-                      uintptr_t retaddr, MemOp op)
-{
-    MemoryRegionSection *section;
-    hwaddr mr_offset;
-    MemoryRegion *mr;
-    MemTxResult r;
-
-    section = io_prepare(&mr_offset, env, full->xlat_section,
-                         full->attrs, addr, retaddr);
-    mr = section->mr;
-
-    {
-        QEMU_IOTHREAD_LOCK_GUARD();
-        r = memory_region_dispatch_write(mr, mr_offset, val, op, full->attrs);
-    }
-
-    if (r != MEMTX_OK) {
-        io_failed(env, full, addr, memop_size(op), MMU_DATA_STORE, mmu_idx,
-                  r, retaddr);
-    }
-}
-
 /* Return true if ADDR is present in the victim tlb, and has been copied
    back to the main tlb.  */
 static bool victim_tlb_hit(CPUArchState *env, size_t mmu_idx, size_t index,
@@ -2682,39 +2658,41 @@ static uint64_t do_st_mmio_leN(CPUArchState *env, CPUTLBEntryFull *full,
                                uint64_t val_le, vaddr addr, int size,
                                int mmu_idx, uintptr_t ra)
 {
+    MemoryRegionSection *section;
+    hwaddr mr_offset;
+    MemoryRegion *mr;
+    MemTxAttrs attrs;
+
     tcg_debug_assert(size > 0 && size <= 8);
 
+    attrs = full->attrs;
+    section = io_prepare(&mr_offset, env, full->xlat_section, attrs, addr, ra);
+    mr = section->mr;
+
     do {
+        MemOp this_mop;
+        unsigned this_size;
+        MemTxResult r;
+
         /* Store aligned pieces up to 8 bytes. */
-        switch ((size | (int)addr) & 7) {
-        case 1:
-        case 3:
-        case 5:
-        case 7:
-            io_writex(env, full, mmu_idx, val_le, addr, ra, MO_UB);
-            val_le >>= 8;
-            size -= 1;
-            addr += 1;
-            break;
-        case 2:
-        case 6:
-            io_writex(env, full, mmu_idx, val_le, addr, ra, MO_LEUW);
-            val_le >>= 16;
-            size -= 2;
-            addr += 2;
-            break;
-        case 4:
-            io_writex(env, full, mmu_idx, val_le, addr, ra, MO_LEUL);
-            val_le >>= 32;
-            size -= 4;
-            addr += 4;
-            break;
-        case 0:
-            io_writex(env, full, mmu_idx, val_le, addr, ra, MO_LEUQ);
+        this_mop = ctz32(size | (int)addr | 8);
+        this_size = 1 << this_mop;
+        this_mop |= MO_LE;
+
+        r = memory_region_dispatch_write(mr, mr_offset, val_le,
+                                         this_mop, attrs);
+        if (unlikely(r != MEMTX_OK)) {
+            io_failed(env, full, addr, this_size, MMU_DATA_STORE,
+                      mmu_idx, r, ra);
+        }
+        if (this_size == 8) {
             return 0;
-        default:
-            qemu_build_not_reached();
         }
+
+        val_le >>= this_size * 8;
+        addr += this_size;
+        mr_offset += this_size;
+        size -= this_size;
     } while (size);
 
     return val_le;
-- 
2.39.5