s390x/css: activate ChannelSubSys migration

Turn on migration for the channel subsystem for the next machine.  For
legacy machines we still have to do things the old way.

Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Message-Id: <20170711145441.33925-6-pasic@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

hw/s390x/css.c

@@ -408,6 +408,11 @@ static int subch_dev_post_load(void *opaque, int version_id)
     return 0;
 }
 
+void css_register_vmstate(void)
+{
+    vmstate_register(NULL, 0, &vmstate_css, &channel_subsys);
+}
+
 IndAddr *get_indicator(hwaddr ind_addr, int len)
 {
     IndAddr *indicator;

hw/s390x/s390-virtio-ccw.c

@@ -209,7 +209,7 @@ static void ccw_machine_class_init(ObjectClass *oc, void *data)
 
     s390mc->ri_allowed = true;
     s390mc->cpu_model_allowed = true;
-    s390mc->css_migration_enabled = false; /* TODO: set to true */
+    s390mc->css_migration_enabled = true;
     mc->init = ccw_init;
     mc->reset = s390_machine_reset;
     mc->hot_add_cpu = s390_hot_add_cpu;
@@ -490,10 +490,9 @@ bool css_migration_enabled(void)
 
 static void ccw_machine_2_10_instance_options(MachineState *machine)
 {
-    /*
-     * TODO Once preparations are done register vmstate for the css if
-     * css_migration_enabled().
-     */
+    if (css_migration_enabled()) {
+        css_register_vmstate();
+    }
 }
 
 static void ccw_machine_2_10_class_options(MachineClass *mc)

include/hw/s390x/css.h

@@ -234,4 +234,8 @@ extern PropertyInfo css_devid_ro_propinfo;
  */
 SubchDev *css_create_sch(CssDevId bus_id, bool is_virtual, bool squash_mcss,
                          Error **errp);
+
+/** Turn on css migration */
+void css_register_vmstate(void);
+
 #endif