css: SCHIB measurement block origin must be aligned

The Measurement Block Origin inside the SCHIB is used when
Measurement Block format 1 is in used and must be aligned
on 64 bytes otherwise an operand exception is recognized
when issuing the Modify Sub CHannel (MSCH) instruction.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <1613741973-3711-2-git-send-email-pmorel@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

target/s390x/ioinst.c

@@ -121,6 +121,12 @@ static int ioinst_schib_valid(SCHIB *schib)
     if (be32_to_cpu(schib->pmcw.chars) & PMCW_CHARS_MASK_XMWME) {
         return 0;
     }
+    /* for MB format 1 bits 26-31 of word 11 must be 0 */
+    /* MBA uses words 10 and 11, it means align on 2**6 */
+    if ((be16_to_cpu(schib->pmcw.chars) & PMCW_CHARS_MASK_MBFC) &&
+        (be64_to_cpu(schib->mba) & 0x03fUL)) {
+        return 0;
+    }
     return 1;
 }