i8254: Open-code timer restore

Same as for the APIC: To enable migration between accelerated and
non-accelerated models, we need to arm the channel 0 timer only inside
the emulated PIT model. The common code just saves/restores that timer
to the the next_transition_time field.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

hw/i8254.c

@@ -300,6 +300,17 @@ static const MemoryRegionOps pit_ioport_ops = {
     .old_portio = pit_portio
 };
 
+static void pit_post_load(PITCommonState *s)
+{
+    PITChannelState *sc = &s->channels[0];
+
+    if (sc->next_transition_time != -1) {
+        qemu_mod_timer(sc->irq_timer, sc->next_transition_time);
+    } else {
+        qemu_del_timer(sc->irq_timer);
+    }
+}
+
 static int pit_initfn(PITCommonState *pit)
 {
     PITChannelState *s;
@@ -329,6 +340,7 @@ static void pit_class_initfn(ObjectClass *klass, void *data)
     k->init = pit_initfn;
     k->set_channel_gate = pit_set_channel_gate;
     k->get_channel_info = pit_get_channel_info_common;
+    k->post_load = pit_post_load;
     dc->reset = pit_reset;
     dc->props = pit_properties;
 }

hw/i8254_common.c

@@ -211,6 +211,7 @@ static const VMStateDescription vmstate_pit_channel = {
 static int pit_load_old(QEMUFile *f, void *opaque, int version_id)
 {
     PITCommonState *pit = opaque;
+    PITCommonClass *c = PIT_COMMON_GET_CLASS(pit);
     PITChannelState *s;
     int i;
 
@@ -234,11 +235,13 @@ static int pit_load_old(QEMUFile *f, void *opaque, int version_id)
         qemu_get_8s(f, &s->gate);
         s->count_load_time = qemu_get_be64(f);
         s->irq_disabled = 0;
-        if (s->irq_timer) {
+        if (i == 0) {
             s->next_transition_time = qemu_get_be64(f);
-            qemu_get_timer(f, s->irq_timer);
         }
     }
+    if (c->post_load) {
+        c->post_load(pit);
+    }
     return 0;
 }
 
@@ -275,7 +278,8 @@ static const VMStateDescription vmstate_pit_common = {
         VMSTATE_UINT32_V(channels[0].irq_disabled, PITCommonState, 3),
         VMSTATE_STRUCT_ARRAY(channels, PITCommonState, 3, 2,
                              vmstate_pit_channel, PITChannelState),
-        VMSTATE_TIMER(channels[0].irq_timer, PITCommonState),
+        VMSTATE_INT64(channels[0].next_transition_time,
+                      PITCommonState), /* formerly irq_timer */
         VMSTATE_END_OF_LIST()
     }
 };