diff --git a/hw/char/serial.c b/hw/char/serial.c
index 7061aacbce9cd6a63449129c1e102047eb2543bc..41b5e61977d362e2cda86707d4255bb6486a1993 100644
--- a/hw/char/serial.c
+++ b/hw/char/serial.c
@@ -961,6 +961,9 @@ void serial_set_frequency(SerialState *s, uint32_t frequency)
 const MemoryRegionOps serial_io_ops = {
     .read = serial_ioport_read,
     .write = serial_ioport_write,
+    .valid = {
+        .unaligned = 1,
+    },
     .impl = {
         .min_access_size = 1,
         .max_access_size = 1,