[PATCH v2 7/9] accel/tcg: Add TLB_CHECK_ALIGNED

[Richard Henderson]

This creates a per-page method for checking of alignment.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 include/exec/cpu-all.h |  4 +++-
 accel/tcg/cputlb.c     | 27 ++++++++++++++++++++++++++-
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h
index 8018ce783e..e61100fc80 100644
--- a/include/exec/cpu-all.h
+++ b/include/exec/cpu-all.h
@@ -346,8 +346,10 @@ CPUArchState *cpu_copy(CPUArchState *env);
 #define TLB_BSWAP            (1 << 0)
 /* Set if TLB entry contains a watchpoint.  */
 #define TLB_WATCHPOINT       (1 << 1)
+/* Set if TLB entry requires aligned accesses.  */
+#define TLB_CHECK_ALIGNED    (1 << 2)
 
-#define TLB_SLOW_FLAGS_MASK  (TLB_BSWAP | TLB_WATCHPOINT)
+#define TLB_SLOW_FLAGS_MASK  (TLB_BSWAP | TLB_WATCHPOINT | TLB_CHECK_ALIGNED)
 
 /* The two sets of flags must not overlap. */
 QEMU_BUILD_BUG_ON(TLB_FLAGS_MASK & TLB_SLOW_FLAGS_MASK);
diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c
index 61f4d94a4d..cb7b4b01e9 100644
--- a/accel/tcg/cputlb.c
+++ b/accel/tcg/cputlb.c
@@ -1553,7 +1553,7 @@ static int probe_access_internal(CPUArchState *env, 
target_ulong addr,
     flags |= full->slow_flags[access_type];
 
     /* Fold all "mmio-like" bits into TLB_MMIO.  This is not RAM.  */
-    if (unlikely(flags & ~(TLB_WATCHPOINT | TLB_NOTDIRTY))) {
+    if (flags & ~(TLB_WATCHPOINT | TLB_NOTDIRTY | TLB_CHECK_ALIGNED)) {
         *phost = NULL;
         return TLB_MMIO;
     }
@@ -1909,6 +1909,31 @@ static bool mmu_lookup(CPUArchState *env, target_ulong 
addr, MemOpIdx oi,
         tcg_debug_assert((flags & TLB_BSWAP) == 0);
     }
 
+    /*
+     * This alignment check differs from the one above, in that this is
+     * based on the atomicity of the operation. The intended use case is
+     * the ARM memory type field of each PTE, where access to pages with
+     * Device memory type require alignment.
+     */
+    if (unlikely(flags & TLB_CHECK_ALIGNED)) {
+        MemOp size = l->memop & MO_SIZE;
+
+        switch (l->memop & MO_ATOM_MASK) {
+        case MO_ATOM_NONE:
+            size = MO_8;
+            break;
+        case MO_ATOM_IFALIGN_PAIR:
+        case MO_ATOM_WITHIN16_PAIR:
+            size = size ? size - 1 : 0;
+            break;
+        default:
+            break;
+        }
+        if (addr & ((1 << size) - 1)) {
+            cpu_unaligned_access(env_cpu(env), addr, type, l->mmu_idx, ra);
+        }
+    }
+
     return crosspage;
 }
 
-- 
2.34.1