[PATCH] hw/char/pl011: Fix clock migration failure

[Gavin Shan <gshan@redhat.com>]

There is a added clock to trace buad rate change since v5.2.0 by
commit aac63e0e6ea3 ("hw/char/pl011: add a clock input"). The added
clock causes migration failure. For example, migration from v5.2.0
to v5.1.0 can fail with the following error messages:

   qemu-system-aarch64: error while loading state for instance 0x0 \
                        of device 'pl011'
   qemu-system-aarch64: load of migration failed: No such file or \
                        directory

This fixes the issue by reporting the baud rate change at post load
time so that the clock won't be migrated by sub-section to avoid the
migration failure.

Cc: qemu-stable@nongnu.org
Fixes: aac63e0e6ea3 ("hw/char/pl011: add a clock input")
Signed-off-by: Gavin Shan <gshan@redhat.com>
---
 hw/char/pl011.c | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/hw/char/pl011.c b/hw/char/pl011.c
index c5621a195f..401bd28536 100644
--- a/hw/char/pl011.c
+++ b/hw/char/pl011.c
@@ -322,20 +322,20 @@ static const MemoryRegionOps pl011_ops = {
     .endianness = DEVICE_NATIVE_ENDIAN,
 };
 
-static const VMStateDescription vmstate_pl011_clock = {
-    .name = "pl011/clock",
-    .version_id = 1,
-    .minimum_version_id = 1,
-    .fields = (VMStateField[]) {
-        VMSTATE_CLOCK(clk, PL011State),
-        VMSTATE_END_OF_LIST()
-    }
-};
+static int pl011_post_load(void *opaque, int version_id)
+{
+    PL011State *s = PL011(opaque);
+
+    pl011_trace_baudrate_change(s);
+
+    return 0;
+}
 
 static const VMStateDescription vmstate_pl011 = {
     .name = "pl011",
     .version_id = 2,
     .minimum_version_id = 2,
+    .post_load = pl011_post_load,
     .fields = (VMStateField[]) {
         VMSTATE_UINT32(readbuff, PL011State),
         VMSTATE_UINT32(flags, PL011State),
@@ -355,10 +355,6 @@ static const VMStateDescription vmstate_pl011 = {
         VMSTATE_INT32(read_trigger, PL011State),
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (const VMStateDescription * []) {
-        &vmstate_pl011_clock,
-        NULL
-    }
 };
 
 static Property pl011_properties[] = {
-- 
2.23.0