Re: [PATCH v1 02/12] s390x/tcg: fix ignoring bit 63 when setting the storage key in SSKE

[Thomas Huth]

On 06/08/2021 08.19, Thomas Huth wrote:
> On 05/08/2021 17.27, David Hildenbrand wrote:
> > The last bit has to be ignored.
> >
> > Signed-off-by: David Hildenbrand <david@redhat.com>
> > ---
> >   target/s390x/tcg/mem_helper.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/target/s390x/tcg/mem_helper.c b/target/s390x/tcg/mem_helper.c
> > index e0befd0f03..3c0820dd74 100644
> > --- a/target/s390x/tcg/mem_helper.c
> > +++ b/target/s390x/tcg/mem_helper.c
> > @@ -2210,7 +2210,7 @@ void HELPER(sske)(CPUS390XState *env, uint64_t r1, 
> > uint64_t r2)
> >           skeyclass = S390_SKEYS_GET_CLASS(ss);
> >       }
> > -    key = (uint8_t) r1;
> > +    key = r1 & 0xfe;
>
> I'm not sure about this one ... could you cite a sentence in the PoP where 
> this is declared? For me it rather sounds like SSKE always sets the whole 
> storage key...

Ah, never mind, I missed that the rightmost bit is undefined and thus this 
is likely ok. Did you check this on a real CPU, though?

 Thomas