diff --git a/configure b/configure
index e2b389d..72d3df8 100755
--- a/configure
+++ b/configure
@@ -697,7 +697,11 @@ case "$cpu" in
            fi
            ;;
     s390)
-           QEMU_CFLAGS="-march=z900 $QEMU_CFLAGS"
+           QEMU_CFLAGS="-march=z990 $QEMU_CFLAGS"
+           ;;
+    s390x)
+           QEMU_CFLAGS="-m64 -march=z9-109 $QEMU_CFLAGS"
+           LDFLAGS="-m64 $LDFLAGS"
            ;;
     i386)
            QEMU_CFLAGS="-m32 $QEMU_CFLAGS"