[Qemu-devel] [PATCH 1/2] s390/ipl: Fix boot order

[Christian Borntraeger]

The latest ipl code adaptions collided with some of the virtio
refactoring rework. This resulted in always booting the first
disk. Let's fix booting from a given ID.
The new code also checks for command lines without bootindex to
avoid random behaviour when accessing dev_st (==0).

We need to get a VirtioCcwDevice from the device_state (but only 
get a VirtIODevice). An object_get_parent() accessor would be
useful here, but going via the parent_bus should also work.

Signed-off-by: Christian Borntraeger <address@hidden>
CC: address@hidden
---
Changelog: 
Version 2: Review feedback from Andreas Faerber regarding parent
accesses, typos and parent_bus.

 hw/s390x/ipl.c | 21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/hw/s390x/ipl.c b/hw/s390x/ipl.c
index 0aeb003..11397ea 100644
--- a/hw/s390x/ipl.c
+++ b/hw/s390x/ipl.c
@@ -154,17 +154,18 @@ static void s390_ipl_reset(DeviceState *dev)
     env->psw.mask = IPL_PSW_MASK;
 
     if (!ipl->kernel) {
-        /* booting firmware, tell what device to boot from */
+        /* Tell firmware, if there is a preferred boot device */
+        env->regs[7] = -1;
         DeviceState *dev_st = get_boot_device(0);
-        VirtioCcwDevice *ccw_dev = (VirtioCcwDevice *) object_dynamic_cast(
-                OBJECT(&(dev_st->parent_obj)), "virtio-blk-ccw");
-
-        if (ccw_dev) {
-            env->regs[7] = ccw_dev->sch->cssid << 24 |
-                           ccw_dev->sch->ssid << 16 |
-                           ccw_dev->sch->devno;
-        } else {
-            env->regs[7] = -1;
+        if (dev_st) {
+            VirtioCcwDevice *ccw_dev = VIRTIO_CCW_DEVICE(
+                OBJECT(qdev_get_parent_bus(dev_st)->parent));
+
+            if (ccw_dev) {
+                env->regs[7] = ccw_dev->sch->cssid << 24 |
+                               ccw_dev->sch->ssid << 16 |
+                               ccw_dev->sch->devno;
+            }
         }
     }
 
-- 
1.8.1.4