watch_mem_write: implement 8-byte accesses

Aligned 8-byte memory writes by a 64-bit target on a 64-bit host should
always turn into atomic 8-byte writes on the host, however a write
write watchpoint would end up tearing the 8-byte write into two 4-byte
writes in access_with_adjusted_size().

Reported-by: Andrew Baumann <Andrew.Baumann@microsoft.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/exec.c b/exec.c
index b58bc4eff75c4d55793bfd42ec518c839cbc02e0..db5ae2311893b00f6aa7b3950c286f253fcbbc80 100644 (file)
--- a/exec.c
+++ b/exec.c
@@ -2503,6 +2503,9 @@ static MemTxResult watch_mem_read(void *opaque, hwaddr addr, uint64_t *pdata,
     case 4:
         data = address_space_ldl(as, addr, attrs, &res);
         break;
+    case 8:
+        data = address_space_ldq(as, addr, attrs, &res);
+        break;
     default: abort();
     }
     *pdata = data;
@@ -2528,6 +2531,9 @@ static MemTxResult watch_mem_write(void *opaque, hwaddr addr,
     case 4:
         address_space_stl(as, addr, val, attrs, &res);
         break;
+    case 8:
+        address_space_stq(as, addr, val, attrs, &res);
+        break;
     default: abort();
     }
     return res;
@@ -2537,6 +2543,16 @@ static const MemoryRegionOps watch_mem_ops = {
     .read_with_attrs = watch_mem_read,
     .write_with_attrs = watch_mem_write,
     .endianness = DEVICE_NATIVE_ENDIAN,
+    .valid = {
+        .min_access_size = 1,
+        .max_access_size = 8,
+        .unaligned = false,
+    },
+    .impl = {
+        .min_access_size = 1,
+        .max_access_size = 8,
+        .unaligned = false,
+    },
 };
 
 static MemTxResult flatview_write(FlatView *fv, hwaddr addr, MemTxAttrs attrs,