[PATCH v4 4/4] hw/s390x: compat handling for backward migration

[Shalini Chellathurai Saroja]

Add Control-Program Identification (CPI) device to QOM only when the virtual
machine supports CPI. CPI is supported from "s390-ccw-virtio-10.0" machine
and higher.

Signed-off-by: Shalini Chellathurai Saroja <shal...@linux.ibm.com>
---
 hw/s390x/s390-virtio-ccw.c         | 10 +++++++++-
 include/hw/s390x/s390-virtio-ccw.h |  1 +
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 7f28cbd1de..81832ee638 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -274,6 +274,7 @@ static void s390_create_sclpcpi(SCLPDevice *sclp)
 static void ccw_init(MachineState *machine)
 {
     MachineClass *mc = MACHINE_GET_CLASS(machine);
+    S390CcwMachineClass *s390mc = S390_CCW_MACHINE_CLASS(mc);
     S390CcwMachineState *ms = S390_CCW_MACHINE(machine);
     int ret;
     VirtualCssBus *css_bus;
@@ -336,7 +337,10 @@ static void ccw_init(MachineState *machine)
     s390_init_tod();
 
     /* init SCLP event Control-Program Identification */
-    s390_create_sclpcpi(ms->sclp);
+    if (s390mc->use_cpi) {
+        s390_create_sclpcpi(ms->sclp);
+    }
+
 }
 
 static void s390_cpu_plug(HotplugHandler *hotplug_dev,
@@ -827,6 +831,7 @@ static void ccw_machine_class_init(ObjectClass *oc, void 
*data)
 
     s390mc->hpage_1m_allowed = true;
     s390mc->max_threads = 1;
+    s390mc->use_cpi = true;
     mc->reset = s390_machine_reset;
     mc->block_default_type = IF_VIRTIO;
     mc->no_cdrom = 1;
@@ -955,6 +960,9 @@ static void ccw_machine_9_2_class_options(MachineClass *mc)
         { TYPE_S390_PCI_DEVICE, "relaxed-translation", "off", },
     };
 
+    S390CcwMachineClass *s390mc = S390_CCW_MACHINE_CLASS(mc);
+    s390mc->use_cpi = false;
+
     ccw_machine_10_0_class_options(mc);
     compat_props_add(mc->compat_props, hw_compat_9_2, hw_compat_9_2_len);
     compat_props_add(mc->compat_props, compat, G_N_ELEMENTS(compat));
diff --git a/include/hw/s390x/s390-virtio-ccw.h 
b/include/hw/s390x/s390-virtio-ccw.h
index 686d9497d2..fc4112fbf5 100644
--- a/include/hw/s390x/s390-virtio-ccw.h
+++ b/include/hw/s390x/s390-virtio-ccw.h
@@ -55,6 +55,7 @@ struct S390CcwMachineClass {
     /*< public >*/
     bool hpage_1m_allowed;
     int max_threads;
+    bool use_cpi;
 };
 
 /* 1M huge page mappings allowed by the machine */
-- 
2.49.0