[Qemu-stable] [PATCH 44/56] s390x/ipl: fix reboots for migration from different bios

[Michael Roth]

From: David Hildenbrand <address@hidden>

When migrating from a different QEMU version, the start_address and
bios_start_address may differ. During migration these values are migrated
and overwrite the values that were detected by QEMU itself.

On a reboot, QEMU will reload its own BIOS, but use the migrated start
addresses, which does not work if the values differ.

Fix this by not relying on the migrated values anymore, but still
provide them during migration, so existing QEMUs continue to work.

Signed-off-by: David Hildenbrand <address@hidden>
Cc: address@hidden
Signed-off-by: Cornelia Huck <address@hidden>
(cherry picked from commit bb0995468a39f14077ceaa8ed5afdca849f00c7c)
Signed-off-by: Michael Roth <address@hidden>
---
 hw/s390x/ipl.c | 11 +++++++++--
 hw/s390x/ipl.h |  2 ++
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/hw/s390x/ipl.c b/hw/s390x/ipl.c
index f104200..3173dcf 100644
--- a/hw/s390x/ipl.c
+++ b/hw/s390x/ipl.c
@@ -47,8 +47,8 @@ static const VMStateDescription vmstate_ipl = {
     .version_id = 0,
     .minimum_version_id = 0,
     .fields = (VMStateField[]) {
-        VMSTATE_UINT64(start_addr, S390IPLState),
-        VMSTATE_UINT64(bios_start_addr, S390IPLState),
+        VMSTATE_UINT64(compat_start_addr, S390IPLState),
+        VMSTATE_UINT64(compat_bios_start_addr, S390IPLState),
         VMSTATE_STRUCT(iplb, S390IPLState, 0, vmstate_iplb, IplParameterBlock),
         VMSTATE_BOOL(iplb_valid, S390IPLState),
         VMSTATE_UINT8(cssid, S390IPLState),
@@ -170,6 +170,13 @@ static void s390_ipl_realize(DeviceState *dev, Error 
**errp)
             stq_p(rom_ptr(INITRD_PARM_SIZE), initrd_size);
         }
     }
+    /*
+     * Don't ever use the migrated values, they could come from a different
+     * BIOS and therefore don't work. But still migrate the values, so
+     * QEMUs relying on it don't break.
+     */
+    ipl->compat_start_addr = ipl->start_addr;
+    ipl->compat_bios_start_addr = ipl->bios_start_addr;
     qemu_register_reset(qdev_reset_all_fn, dev);
 error:
     error_propagate(errp, err);
diff --git a/hw/s390x/ipl.h b/hw/s390x/ipl.h
index 6b48ed7..0bfb72b 100644
--- a/hw/s390x/ipl.h
+++ b/hw/s390x/ipl.h
@@ -33,7 +33,9 @@ struct S390IPLState {
     /*< private >*/
     DeviceState parent_obj;
     uint64_t start_addr;
+    uint64_t compat_start_addr;
     uint64_t bios_start_addr;
+    uint64_t compat_bios_start_addr;
     bool enforce_bios;
     IplParameterBlock iplb;
     bool iplb_valid;
-- 
1.9.1