From: Arwed Meyer <arwed.meyer@gmx.de>

Unaligned i/o access on serial UART works on real PCs.
This is used for example by FreeDOS CTMouse driver. Without this it
can't reset and detect serial mice.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/77
Signed-off-by: Arwed Meyer <arwed.meyer@gmx.de>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20220911181840.8933-6-arwed.meyer@gmx.de>
---
 hw/char/serial.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/hw/char/serial.c b/hw/char/serial.c
index 7061aacbce..41b5e61977 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,
-- 
2.37.3