Re: [qemu-s390x] [PATCH v1 for-2.12 5/5] s390x/tcg: wire up STORE CHANNEL REPORT WORD

[David Hildenbrand]

On 04.12.2017 18:53, Cornelia Huck wrote:
> On Mon, 4 Dec 2017 18:34:36 +0100
> David Hildenbrand <address@hidden> wrote:
> 
>> On 04.12.2017 18:22, Cornelia Huck wrote:
>>> On Mon,  4 Dec 2017 13:55:05 +0100
>>> David Hildenbrand <address@hidden> wrote:
>>>   
>>>> We somehow missed that, new kernels require it.  
>>>
>>> Why _new_ kernels? I think we have unconditionally issued stcrw since
>>> back in 2.2?  
>>
>> Okay, the problem is then rather related to my setup. No ccw devices ->
>> no stcrw.
>>
>> How could we ever add ccw devices to a TCG guest then?
> 
> Hotplug never worked before your patches. Coldplug does not create
> machine checks and thus does not trigger the guest to do STCRW. (Only
> STSCH, in keeping with "all channel I/O acronyms look the same".)
> 

But booting Fedora 26/27 without any involved hotplugs (therefore
machine checks) triggers a STCRW.

That's how I originally found it. (I started playing with machine checks
after I had fedora 26/27 running)

-- 

Thanks,

David / dhildenb