Re: [Qemu-devel] hw/s390x/ipl: Dubious use of qdev_reset_all_fn

[David Hildenbrand <david@redhat.com>]

On 24.05.19 20:36, David Hildenbrand wrote:
> On 24.05.19 20:28, Christian Borntraeger wrote:
>>
>>
>> On 24.05.19 20:04, David Hildenbrand wrote:
>>> On 24.05.19 19:54, Philippe Mathieu-Daudé wrote:
>>>> Hi Christian,
>>>>
>>>> I'm having hard time to understand why the S390_IPL object calls
>>>> qemu_register_reset(qdev_reset_all_fn) in its realize() method, while
>>>> being QOM'ified (it has a reset method).
>>>>
>>>> It doesn't seem to have a qdev children added explicitly to it.
>>>> I see it is used as a singleton, what else am I missing?
>>>>
>>>> Thanks,
>>>>
>>>> Phil.
>>>>
>>>
>>> Looks like I added it back then (~4 years ago) when converting it into a
>>> TYPE_DEVICE.
>>>
>>> I could imagine that - back then - this was needed because only
>>> TYPE_SYS_BUS_DEVICE would recursively get reset.
>>
>> Yes, back then singleton devices were not recursively resetted. Has that changed?
> 
> Hacking that call out, I don't see it getting called anymore. So it is
> still required. The question is if it can be reworked.
> 

Yes, as it is not a sysbus device, it won't get reset.
The owner (machine) has to take care of this. The following works:


diff --git a/hw/s390x/ipl.c b/hw/s390x/ipl.c
index b93750c14e..91a31c2cd0 100644
--- a/hw/s390x/ipl.c
+++ b/hw/s390x/ipl.c
@@ -232,7 +232,6 @@ static void s390_ipl_realize(DeviceState *dev, Error **errp)
      */
     ipl->compat_start_addr = ipl->start_addr;
     ipl->compat_bios_start_addr = ipl->bios_start_addr;
-    qemu_register_reset(qdev_reset_all_fn, dev);
 error:
     error_propagate(errp, err);
 }
diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index bbc6e8fa0b..658ab529a1 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -338,6 +338,11 @@ static inline void s390_do_cpu_ipl(CPUState *cs, run_on_cpu_data arg)
     s390_cpu_set_state(S390_CPU_STATE_OPERATING, cpu);
 }
 
+static void s390_ipl_reset(void)
+{
+    qdev_reset_all(DEVICE(object_resolve_path_type("", TYPE_S390_IPL, NULL)));
+}
+
 static void s390_machine_reset(void)
 {
     enum s390_reset reset_type;
@@ -353,6 +358,7 @@ static void s390_machine_reset(void)
     case S390_RESET_EXTERNAL:
     case S390_RESET_REIPL:
         qemu_devices_reset();
+        s390_ipl_reset();
         s390_crypto_reset();
 
         /* configure and start the ipl CPU only */



-- 

Thanks,

David / dhildenb