s390x: Introduce PV query interface

Introduce an interface over which we can get information about UV data.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Steffen Eiden <seiden@linux.ibm.com>
Reviewed-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
Acked-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20221017083822.43118-8-frankja@linux.ibm.com>
diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 03855c7..1cc20d8 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -366,6 +366,12 @@
 
     ms->pv = true;
 
+    /* Will return 0 if API is not available since it's not vital */
+    rc = s390_pv_query_info();
+    if (rc) {
+        goto out_err;
+    }
+
     /* Set SE header and unpack */
     rc = s390_ipl_prepare_pv_header();
     if (rc) {