Re: [PATCH 1/1] hw/char: imx_serial: add missing migration state

On 7/15/26 16:18, Tao Ding wrote:
> Add ucr2 from imx_serial to vmstate, and increment the version_id.
> 
> Migrating on sabrelite can reproduce this issue:
> 1. Prepare the U-Boot required for sabrelite. (according to sabrelite.rst)
> 2. Compile qemu
>      $ mkdir build && cd build && ../configure --target-list="arm-softmmu" && make -j4
> 3. Start sabrelite and prepare for migration
>      $ ./build/qemu-system-arm -M sabrelite \
>      -smp 1 -m 1G -display none -serial null -serial mon:stdio \
>      -kernel ~/u-boot
> 4. Enter qemu monitor after uboot. (ctrl + a + c)
>      (qemu) stop
>      (qemu) xp /4wx 0x021e8084
>      021e8084: 0x00004027 0x00000784 0x00008000 0x00000a01
>      (qemu) migrate -d file:vmstate
>      (qemu) q
> 
> Load the migrated vmstate, before repairing:
> 
> $ ./build/qemu-system-arm -M sabrelite \
>      -smp 1 -m 1G -display none -serial null -serial mon:stdio \
>      -kernel ~/u-boot -incoming file:vmstate
> 
> (ctrl + a + c)
>      QEMU 11.0.50 monitor - type 'help' for more information
>      (qemu) xp /4wx 0x021e8084
>      021e8084: 0x00000004 0x00000784 0x00008000 0x00000a01
>      (qemu) q
> 
> It can be found that the data for address 0x021e8084 (register of usr2 in imx_serial of sabrelite)
> is not the data before the migration.
> 
> After being repaired:
> $ ./build/qemu-system-arm -M sabrelite \
>      -smp 1 -m 1G -display none -serial null -serial mon:stdio \
>      -kernel ~/u-boot -incoming file:vmstate
> (ctrl + a + c)
>      QEMU 11.0.50 monitor - type 'help' for more information
>      (qemu) xp /4wx 0x021e8084
>      021e8084: 0x00004027 0x00000784 0x00008000 0x00000a01
> 
> Signed-off-by: Tao Ding <[email protected]>


Somehow, this grow Cc: qemu-stable@ in the final version which was
applied as v11.1.0-rc0-68-g8833ff95eaf.  I don't think this is a
good candidate for the stable series, since this fix changes the
migration stream format, which is very difficult to do in the stable
series.

FWIW.

Thanks,

/mjt

>   hw/char/imx_serial.c | 5 +++--
>   1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/char/imx_serial.c b/hw/char/imx_serial.c
> index 080b7f6331..fb41ee2ac5 100644
> --- a/hw/char/imx_serial.c
> +++ b/hw/char/imx_serial.c
> @@ -43,14 +43,15 @@
>   
>   static const VMStateDescription vmstate_imx_serial = {
>       .name = TYPE_IMX_SERIAL,
> -    .version_id = 3,
> -    .minimum_version_id = 3,
> +    .version_id = 4,
> +    .minimum_version_id = 4,
>       .fields = (const VMStateField[]) {
>           VMSTATE_FIFO32(rx_fifo, IMXSerialState),
>           VMSTATE_TIMER(ageing_timer, IMXSerialState),
>           VMSTATE_UINT32(usr1, IMXSerialState),
>           VMSTATE_UINT32(usr2, IMXSerialState),
>           VMSTATE_UINT32(ucr1, IMXSerialState),
> +        VMSTATE_UINT32(ucr2, IMXSerialState),
>           VMSTATE_UINT32(uts1, IMXSerialState),
>           VMSTATE_UINT32(onems, IMXSerialState),
>           VMSTATE_UINT32(ufcr, IMXSerialState),