Re: [Qemu-devel] [PATCH for-2.4] watchdog/diag288: correctly register for system reset requests

[Paolo Bonzini <pbonzini@redhat.com>]

On 07/07/2015 12:51, Peter Crosthwaite wrote:
> On Tue, Jul 7, 2015 at 1:53 AM, Cornelia Huck <cornelia.huck@de.ibm.com> wrote:
>> From: Xu Wang <gesaint@linux.vnet.ibm.com>
>>
>> The diag288 watchdog is no sysbus device, therefore it doesn't get
>> triggered on resets automatically using dc->reset.
>>
>> Let's register the reset handler manually, so we get correctly notified
>> again when a system reset was requested. Also reset the watchdog on
>> subsystem resets that don't trigger a full system reset.
>>
>> Signed-off-by: Xu Wang <gesaint@linux.vnet.ibm.com>
>> Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
>> Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
>> ---
>>  hw/s390x/s390-virtio-ccw.c | 6 +++++-
>>  hw/watchdog/wdt_diag288.c  | 8 ++++++++
>>  2 files changed, 13 insertions(+), 1 deletion(-)
>>
>> diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
>> index 3d20d6a..4c51d1a 100644
>> --- a/hw/s390x/s390-virtio-ccw.c
>> +++ b/hw/s390x/s390-virtio-ccw.c
>> @@ -36,7 +36,7 @@ typedef struct S390CcwMachineState {
>>
>>  void io_subsystem_reset(void)
>>  {
>> -    DeviceState *css, *sclp, *flic;
>> +    DeviceState *css, *sclp, *flic, *diag288;
>>
>>      css = DEVICE(object_resolve_path_type("", "virtual-css-bridge", NULL));
>>      if (css) {
>> @@ -51,6 +51,10 @@ void io_subsystem_reset(void)
>>      if (flic) {
>>          qdev_reset_all(flic);
>>      }
>> +    diag288 = DEVICE(object_resolve_path_type("", "diag288", NULL));
>> +    if (diag288) {
>> +        qdev_reset_all(diag288);
>> +    }
>>  }
>>
>>  static int virtio_ccw_hcall_notify(const uint64_t *args)
>> diff --git a/hw/watchdog/wdt_diag288.c b/hw/watchdog/wdt_diag288.c
>> index 1185e06..2a885a4 100644
>> --- a/hw/watchdog/wdt_diag288.c
>> +++ b/hw/watchdog/wdt_diag288.c
>> @@ -40,6 +40,13 @@ static void wdt_diag288_reset(DeviceState *dev)
>>      timer_del(diag288->timer);
>>  }
>>
>> +static void diag288_reset(void *opaque)
>> +{
>> +    DeviceState *diag288 = opaque;
>> +
>> +    wdt_diag288_reset(diag288);
>> +}
>> +
>>  static void diag288_timer_expired(void *dev)
>>  {
>>      qemu_log_mask(CPU_LOG_RESET, "Watchdog timer expired.\n");
>> @@ -80,6 +87,7 @@ static void wdt_diag288_realize(DeviceState *dev, Error **errp)
>>  {
>>      DIAG288State *diag288 = DIAG288(dev);
>>
>> +    qemu_register_reset(diag288_reset, diag288);
> 
> Doesn't seem right. Even if it is not a SBD it should still sit in the
> QOM tree in a place where the reset is reached. Where is this device
> in the QOM tree?

Reset doesn't follow the QOM tree.

In fact this is the main reason why I dislike TYPE_DEVICE as a superclass...

Paolo