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

[Christian Borntraeger <borntraeger@de.ibm.com>]

Am 08.07.2015 um 09:54 schrieb Paolo Bonzini:
> 
> 
> 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...

Oh, thats why we were asked to use that instead of sysbus device? ;-)