[Xen-devel] [PATCH][QEMU] serial save load fix

[Ben Guthro <bguthro@xxxxxxxxxxxxxxx>]

NOTE: An applicable subset of this patch was also submitted to upstream qemu.

SUMMARY:
This patch fixes several bugs in serial.c
(1) A typo in serial_save() where qemu_get_8s is called (should be qemu_put_8s)
(2) No support provided in serial_load() for version_id == 1 (should unmarshal
a 1 byte s->divider and should provide a default value for s->fcr
(3) Call serial_ioport_write() to initialize s->fcr. It is not sufficient
to load its value; other hidden values (such as s->recv_fifo.itl) must be
re-initialized.

Signed-off-by: Ben Guthro <bguthro@xxxxxxxxxxxxxxx>
Signed-off-by: Robert Phillips <rphillips@xxxxxxxxxxxxxxx>

diff -r a81184e1f8ae tools/ioemu/hw/serial.c
--- a/tools/ioemu/hw/serial.c
+++ b/tools/ioemu/hw/serial.c
@@ -708,12 +708,13 @@ static void serial_save(QEMUFile *f, voi
   qemu_put_8s(f,&s->lsr);
   qemu_put_8s(f,&s->msr);
   qemu_put_8s(f,&s->scr);
-    qemu_get_8s(f,&s->fcr);
+    qemu_put_8s(f,&s->fcr);
}

static int serial_load(QEMUFile *f, void *opaque, int version_id)
{
   SerialState *s = opaque;
+    uint8_t fcr;

   if(version_id > 2)
       return -EINVAL;
@@ -730,8 +731,13 @@ static int serial_load(QEMUFile *f, void
   qemu_get_8s(f,&s->lsr);
   qemu_get_8s(f,&s->msr);
   qemu_get_8s(f,&s->scr);
-    qemu_get_8s(f,&s->fcr);
-
+    if (version_id >= 2)
+        qemu_get_8s(f,&fcr);
+    else
+        fcr = 0; // disable fifos
+
+    /* Initialize fcr via setter to perform essential side-effects */
+    serial_ioport_write(s, 0x02, fcr);
   return 0;
}

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