Right now we could set an 8-bit storage key via SSKE and retrieve it
again via ISKE, which is against the architecture description:

SSKE:
"
The new seven-bit storage-key value, or selected bits
thereof, is obtained from bit positions 56-62 of gen-
eral register R 1 . The contents of bit positions 0-55
and 63 of the register are ignored.
"

ISKE:
"
The seven-bit storage key is inserted in bit positions
56-62 of general register R 1 , and bit 63 is set to zero.
"

Let's properly ignore bit 63 to create the correct seven-bit storage key.

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;
     skeyclass->set_skeys(ss, addr / TARGET_PAGE_SIZE, 1, &key);
    /*
     * As we can only flush by virtual address and not all the entries
-- 
2.31.1