Re: [kvm-unit-tests PATCH v2 1/1] s390x: add migration test for storage keys

Claudio Imbrenda
2022-05-17T12:29:39Z

On Tue, 17 May 2022 13:44:51 +0200
Janis Schoetterl-Glausch <scgl@linux.ibm.com> wrote:

> On Tue, 2022-05-17 at 10:17 +0200, Nico Boehr wrote:
> > On Mon, 2022-05-16 at 18:47 +0200, Janis Schoetterl-Glausch wrote:
> > > On 5/16/22 11:07, Nico Boehr wrote:
>
> [...]
>
> > > > +               expected_key.val = i * 2;
> > > > +
> > > > +               /* ignore reference bit */
> > >
> > > Why? Are there any implicit references I'm missing?
> >
> > Since the PoP specifies (p. 5-122):
> >
> > "The record of references provided by the reference
> > bit is not necessarily accurate. However, in the major-
> > ity of situations, reference recording approximately
> > coincides with the related storage reference."
> >
> > I don't really see a way to test this properly.
> >
> > Maybe I missed something?
>
> No I think you're right, although in practice the reference bits should
> match. Or did you observe a mismatch?

the point is that the architecture allows for mismatches (in particular
I think it is allowed to overindicate changes)

ignoring that bit is the correct thing to do