Re: [kvm-unit-tests PATCH v6 07/10] s390x: css: msch, enable test

Cornelia Huck
2020-05-14T12:08:44Z

On Tue, 28 Apr 2020 10:27:36 +0200
Pierre Morel <pmorel@linux.ibm.com> wrote:

> On 2020-04-27 15:11, Janosch Frank wrote:
> > On 4/24/20 12:45 PM, Pierre Morel wrote:

> >> This is NOT a routine to really enable the channel, no retry is done,
> >> in case of error, a report is made.
> >
> > Would we expect needing retries for the pong device?
>
> Yes it can be that we need to retry some instructions if we want them to
> succeed.
> This is the case for example if we develop a driver for an operating system.
> When working with firmware, sometime, things do not work at the first
> time. Mostly due to races in silicium, firmware or hypervisor or between
> them all.
>
> Since our purpose is to detect such problems we do not retry
> instructions but report the error.
>
> If we detect such problem we may in the future enhance the tests.

I think I've seen retries needed on z/VM in the past; do you know if
that still happens?