Re: [PATCH] s390x/s390-virtio-ccw: Reset PCI devices during subsystem reset

[Matthew Rosato <mjrosato@linux.ibm.com>]

On 10/15/20 9:37 AM, Niklas Schnelle wrote:
> 
> 
> On 10/15/20 3:34 PM, Christian Borntraeger wrote:
>>
>>
>> On 15.10.20 15:32, Christian Borntraeger wrote:
>>>
>>>
>>> On 15.10.20 15:16, Matthew Rosato wrote:
>>>> Currently, a subsystem reset event leaves PCI devices enabled, causing
>>>> issues post-reset in the guest (an example would be after a kexec).  These
>>>> devices need to be reset during a subsystem reset, allowing them to be
>>>> properly re-enabled afterwards.  Add the S390 PCI host bridge to the list
>>>> of qdevs to be reset during subsystem reset.
>>>>
>>>> Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
>>>> Reviewed-by: Eric Farman <farman@linux.ibm.com>
>>>
>>> Makese sense.
>>> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
>>
>> A question. Is this a stable candidate?
> 
> As this can prevent a SUSE guest (which does kexec during boot because of grub)
> from seeing any PCI devices I'd say yes.
> 

Yes, agreed.

>>
>>>
>>>
>>>> ---
>>>>   hw/s390x/s390-virtio-ccw.c | 1 +
>>>>   1 file changed, 1 insertion(+)
>>>>
>>>> diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
>>>> index e52182f..2e90033 100644
>>>> --- a/hw/s390x/s390-virtio-ccw.c
>>>> +++ b/hw/s390x/s390-virtio-ccw.c
>>>> @@ -101,6 +101,7 @@ static const char *const reset_dev_types[] = {
>>>>       "s390-sclp-event-facility",
>>>>       "s390-flic",
>>>>       "diag288",
>>>> +    TYPE_S390_PCI_HOST_BRIDGE,
>>>>   };
>>>>   
>>>>   static void subsystem_reset(void)
>>>>