[PATCH] pc-bios: s390x: Only set lowcore iplb address on list-directed IPL

["Jason J. Herne" <jjherne@linux.ibm.com>]

The POP states that the IPLB location is only written to 0x14 for
list-directed IPL. Some operating systems expect 0x14 to not change on
boot and will fail IPL if it does change.

Fixes: 9bfc04f9ef6802fff0
Signed-off-by: Jason J. Herne <jjherne@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@de.ibm.com>
---
 pc-bios/s390-ccw/jump2ipl.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/pc-bios/s390-ccw/jump2ipl.c b/pc-bios/s390-ccw/jump2ipl.c
index 767012bf0c..5e3e13f4b0 100644
--- a/pc-bios/s390-ccw/jump2ipl.c
+++ b/pc-bios/s390-ccw/jump2ipl.c
@@ -33,7 +33,10 @@ void jump_to_IPL_code(uint64_t address)
 {
     /* store the subsystem information _after_ the bootmap was loaded */
     write_subsystem_identification();
-    write_iplb_location();
+
+    if (iplb.pbt != S390_IPL_TYPE_CCW) {
+            write_iplb_location();
+    }
 
     /* prevent unknown IPL types in the guest */
     if (iplb.pbt == S390_IPL_TYPE_QEMU_SCSI) {
-- 
2.21.1