Re: [Qemu-devel] [RFC PATCH 3/3] s390x/css: add hint for devno missmatch

[Dr. David Alan Gilbert]

* Halil Pasic (address@hidden) wrote:
> This one has to be fixed up to 's390x: vmstatify config migration for
> virtio-ccw' provided we want to achieve the same as 's390x/css: catch
> section mismatch on load' does.
> 
> Signed-off-by: Halil Pasic <address@hidden>
> ---
> 
> This is on tom of 's390x: vmstatify config migration for virtio-ccw'
               p
> which ain't on top of 's390x/css: catch section mismatch on load' but on
> top of master.  I kind of have a circular dependency here. This is why
> the series is RFC. 
> 
> Wanted to provide an usage example. Faked 'Re: ' so patchew does not
> try to apply this on top of current master.
> ---
>  hw/s390x/css.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/s390x/css.c b/hw/s390x/css.c
> index 348129e1b2..de277d6a3d 100644
> --- a/hw/s390x/css.c
> +++ b/hw/s390x/css.c
> @@ -134,6 +134,10 @@ static const VMStateDescription vmstate_sense_id = {
>  static int subch_dev_post_load(void *opaque, int version_id);
>  static void subch_dev_pre_save(void *opaque);
>  
> +const char err_hint_devno[] = "Devno mismatch, tried to load wrong section!"
> +    " Likely reason: some sequences of plug and unplug  can break"
> +    " migration for machine versions prior to  2.7 (known design flaw).";
> +

That's ok, but I suggest:
   * 'bug' rather than 'design flaw' - it sounds a bit less scary to
     endusers.

Other than that,


Reviewed-by: Dr. David Alan Gilbert <address@hidden>

Dave

>  const VMStateDescription vmstate_subch_dev = {
>      .name = "s390_subch_dev",
>      .version_id = 1,
> @@ -144,7 +148,7 @@ const VMStateDescription vmstate_subch_dev = {
>          VMSTATE_UINT8_EQUAL(cssid, SubchDev),
>          VMSTATE_UINT8_EQUAL(ssid, SubchDev),
>          VMSTATE_UINT16(migrated_schid, SubchDev),
> -        VMSTATE_UINT16(devno, SubchDev),
> +        VMSTATE_UINT16_EQUAL_HINT(devno, SubchDev, err_hint_devno),
>          VMSTATE_BOOL(thinint_active, SubchDev),
>          VMSTATE_STRUCT(curr_status, SubchDev, 0, vmstate_schib, SCHIB),
>          VMSTATE_UINT8_ARRAY(sense_data, SubchDev, 32),
> -- 
> 2.11.2
> 
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK