Re: [PATCH v2] target/s390x: fix execution with icount

[David Hildenbrand]

On 02.11.20 10:41, Pavel Dovgalyuk wrote:
> On 02.11.2020 12:34, David Hildenbrand wrote:
> > On 02.11.20 10:26, Pavel Dovgalyuk wrote:
> > > This patch adds some gen_io_start() calls to allow execution
> > > of s390x targets in icount mode with -smp 1.
> > > It enables deterministic timers and record/replay features.
> >
> > Why do we have to set it for SIGP?
>
> Timer-related instructions obviously needed IO.
> But I'm not familiar with s390, therefore also added IO
> for the instructions that lock iothread mutex, because they
> probably can access some virtual hardware and change the timers.
> But maybe this is not related to SIGP and it takes the mutex
> for other reasons.

SIGP does IPI but also triggers CPU reset, so it deals with timers in 
some sense (reset). So looks like the right thing to do. Thanks!

Acked-by: David Hildenbrand <david@redhat.com>

--
Thanks,

David / dhildenb