On 04.12.2017 18:58, Cornelia Huck wrote: > On Mon, 4 Dec 2017 18:56:00 +0100 > David Hildenbrand <da...@redhat.com> wrote: > >> On 04.12.2017 18:53, Cornelia Huck wrote: >>> On Mon, 4 Dec 2017 18:34:36 +0100 >>> David Hildenbrand <da...@redhat.com> wrote: >>> >>>> On 04.12.2017 18:22, Cornelia Huck wrote: >>>>> On Mon, 4 Dec 2017 13:55:05 +0100 >>>>> David Hildenbrand <da...@redhat.com> 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) >> > > Confused. Do you have a backtrace? (Guest/host) >
Unfortunately not. Strange, I just tried to reproduce but can't trigger it. Maybe aside effect from the other BUGs I have been fixing :) So I'll just rephrase this to "CRW machine check handling requires STCRW." -- Thanks, David / dhildenb
