s390: move css_migration_enabled from machine to css.c

The CSS subsystem uses global variables, just face the truth and use
a variable also for whether the CSS vmstate is in use; remove the
indirection of fetching it from the machine type, which makes the
TCG code depend unnecessarily on the virtio-ccw machine.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20240509170044.190795-4-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

hw/s390x/css.c

@@ -23,6 +23,8 @@
 #include "hw/s390x/s390-virtio-ccw.h"
 #include "hw/s390x/s390-ccw.h"
 
+bool css_migration_enabled = true;
+
 typedef struct CrwContainer {
     CRW crw;
     QTAILQ_ENTRY(CrwContainer) sibling;
@@ -180,7 +182,7 @@ static const VMStateDescription vmstate_orb = {
 
 static bool vmstate_schdev_orb_needed(void *opaque)
 {
-    return css_migration_enabled();
+    return css_migration_enabled;
 }
 
 static const VMStateDescription vmstate_schdev_orb = {
@@ -388,7 +390,7 @@ static int subch_dev_post_load(void *opaque, int version_id)
         css_subch_assign(s->cssid, s->ssid, s->schid, s->devno, s);
     }
 
-    if (css_migration_enabled()) {
+    if (css_migration_enabled) {
         /* No compat voodoo to do ;) */
         return 0;
     }
@@ -412,7 +414,9 @@ static int subch_dev_post_load(void *opaque, int version_id)
 
 void css_register_vmstate(void)
 {
-    vmstate_register(NULL, 0, &vmstate_css, &channel_subsys);
+    if (css_migration_enabled) {
+        vmstate_register(NULL, 0, &vmstate_css, &channel_subsys);
+    }
 }
 
 IndAddr *get_indicator(hwaddr ind_addr, int len)

hw/s390x/s390-virtio-ccw.c

@@ -283,11 +283,9 @@ static void ccw_init(MachineState *machine)
     s390_enable_css_support(s390_cpu_addr2state(0));
 
     ret = css_create_css_image(VIRTUAL_CSSID, true);
-
     assert(ret == 0);
-    if (css_migration_enabled()) {
-        css_register_vmstate();
-    }
+
+    css_register_vmstate();
 
     /* Create VirtIO network adapters */
     s390_create_virtio_net(BUS(css_bus), mc->default_nic);
@@ -749,7 +747,6 @@ static void ccw_machine_class_init(ObjectClass *oc, void *data)
 
     s390mc->ri_allowed = true;
     s390mc->cpu_model_allowed = true;
-    s390mc->css_migration_enabled = true;
     s390mc->hpage_1m_allowed = true;
     s390mc->max_threads = 1;
     mc->init = ccw_init;
@@ -819,11 +816,6 @@ static const TypeInfo ccw_machine_info = {
     },
 };
 
-bool css_migration_enabled(void)
-{
-    return get_machine_class()->css_migration_enabled;
-}
-
 #define DEFINE_CCW_MACHINE(suffix, verstr, latest)                            \
     static void ccw_machine_##suffix##_class_init(ObjectClass *oc,            \
                                                   void *data)                 \
@@ -1179,7 +1171,6 @@ static void ccw_machine_2_9_instance_options(MachineState *machine)
 
 static void ccw_machine_2_9_class_options(MachineClass *mc)
 {
-    S390CcwMachineClass *s390mc = S390_CCW_MACHINE_CLASS(mc);
     static GlobalProperty compat[] = {
         { TYPE_S390_STATTRIB, "migration-enabled", "off", },
         { TYPE_S390_FLIC_COMMON, "migration-enabled", "off", },
@@ -1188,7 +1179,7 @@ static void ccw_machine_2_9_class_options(MachineClass *mc)
     ccw_machine_2_10_class_options(mc);
     compat_props_add(mc->compat_props, hw_compat_2_9, hw_compat_2_9_len);
     compat_props_add(mc->compat_props, compat, G_N_ELEMENTS(compat));
-    s390mc->css_migration_enabled = false;
+    css_migration_enabled = false;
 }
 DEFINE_CCW_MACHINE(2_9, "2.9", false);
 

include/hw/s390x/css.h

@@ -333,4 +333,10 @@ static inline int ccw_dstream_read_buf(CcwDataStream *cds, void *buff, int len)
 #define ccw_dstream_read(cds, v) ccw_dstream_read_buf((cds), &(v), sizeof(v))
 #define ccw_dstream_write(cds, v) ccw_dstream_write_buf((cds), &(v), sizeof(v))
 
+/**
+ * true if (vmstate based) migration of the channel subsystem
+ * is enabled, false if it is disabled.
+ */
+extern bool css_migration_enabled;
+
 #endif

include/hw/s390x/s390-virtio-ccw.h

@@ -46,7 +46,6 @@ struct S390CcwMachineClass {
     /*< public >*/
     bool ri_allowed;
     bool cpu_model_allowed;
-    bool css_migration_enabled;
     bool hpage_1m_allowed;
     int max_threads;
 };
@@ -58,10 +57,4 @@ bool cpu_model_allowed(void);
 /* 1M huge page mappings allowed by the machine */
 bool hpage_1m_allowed(void);
 
-/**
- * Returns true if (vmstate based) migration of the channel subsystem
- * is enabled, false if it is disabled.
- */
-bool css_migration_enabled(void);
-
 #endif