1 files changed, 6 insertions, 0 deletions
diff --git a/target/s390x/ioinst.c b/target/s390x/ioinst.c
index a412926..1ee1152 100644
--- a/target/s390x/ioinst.c
+++ b/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;
 }