s390: sclp signal quiesce support

This implements the sclp signal quiesce event via the SCLP Event
Facility.
This allows to gracefully shutdown a guest by using system_powerdown
notifiers. It creates a service interrupt that will trigger a
Read Event Data command from the guest. This code will then add an
event that is interpreted by linux guests as ctrl-alt-del.

Signed-off-by: Heinz Graalfs <graalfs@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>

hw/s390x/Makefile.objs

@@ -3,3 +3,4 @@ obj-y = s390-virtio-bus.o s390-virtio.o
 obj-y := $(addprefix ../,$(obj-y))
 obj-y += sclp.o
 obj-y += event-facility.o
+obj-y += sclpquiesce.o

hw/s390x/event-facility.c

@@ -315,6 +315,7 @@ static void command_handler(SCLPEventFacility *ef, SCCB *sccb, uint64_t code)
 static int init_event_facility(S390SCLPDevice *sdev)
 {
     SCLPEventFacility *event_facility;
+    DeviceState *quiesce;
 
     event_facility = g_malloc0(sizeof(SCLPEventFacility));
     sdev->ef = event_facility;
@@ -327,6 +328,12 @@ static int init_event_facility(S390SCLPDevice *sdev)
     event_facility->sbus.qbus.allow_hotplug = 0;
     event_facility->qdev = (DeviceState *) sdev;
 
+    quiesce = qdev_create(&event_facility->sbus.qbus, "sclpquiesce");
+    if (!quiesce) {
+        return -1;
+    }
+    qdev_init_nofail(quiesce);
+
     return 0;
 }
 

hw/s390x/sclpquiesce.c

@@ -0,0 +1,123 @@
+/*
+ * SCLP event type
+ *    Signal Quiesce - trigger system powerdown request
+ *
+ * Copyright IBM, Corp. 2012
+ *
+ * Authors:
+ *  Heinz Graalfs <graalfs@de.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or (at your
+ * option) any later version.  See the COPYING file in the top-level directory.
+ *
+ */
+#include <hw/qdev.h>
+#include "sysemu.h"
+#include "sclp.h"
+#include "event-facility.h"
+
+typedef struct SignalQuiesce {
+    EventBufferHeader ebh;
+    uint16_t timeout;
+    uint8_t unit;
+} QEMU_PACKED SignalQuiesce;
+
+static int event_type(void)
+{
+    return SCLP_EVENT_SIGNAL_QUIESCE;
+}
+
+static unsigned int send_mask(void)
+{
+    return SCLP_EVENT_MASK_SIGNAL_QUIESCE;
+}
+
+static unsigned int receive_mask(void)
+{
+    return 0;
+}
+
+static int read_event_data(SCLPEvent *event, EventBufferHeader *evt_buf_hdr,
+                           int *slen)
+{
+    SignalQuiesce *sq = (SignalQuiesce *) evt_buf_hdr;
+
+    if (*slen < sizeof(SignalQuiesce)) {
+        return 0;
+    }
+
+    if (!event->event_pending) {
+        return 0;
+    }
+    event->event_pending = false;
+
+    sq->ebh.length = cpu_to_be16(sizeof(SignalQuiesce));
+    sq->ebh.type = SCLP_EVENT_SIGNAL_QUIESCE;
+    sq->ebh.flags |= SCLP_EVENT_BUFFER_ACCEPTED;
+    /*
+     * system_powerdown does not have a timeout. Fortunately the
+     * timeout value is currently ignored by Linux, anyway
+     */
+    sq->timeout = cpu_to_be16(0);
+    sq->unit = cpu_to_be16(0);
+    *slen -= sizeof(SignalQuiesce);
+
+    return 1;
+}
+
+typedef struct QuiesceNotifier QuiesceNotifier;
+
+static struct QuiesceNotifier {
+    Notifier notifier;
+    SCLPEvent *event;
+} qn;
+
+static void quiesce_powerdown_req(Notifier *n, void *opaque)
+{
+    QuiesceNotifier *qn = container_of(n, QuiesceNotifier, notifier);
+    SCLPEvent *event = qn->event;
+
+    event->event_pending = true;
+    /* trigger SCLP read operation */
+    sclp_service_interrupt(0);
+}
+
+static int quiesce_init(SCLPEvent *event)
+{
+    event->event_type = SCLP_EVENT_SIGNAL_QUIESCE;
+
+    qn.notifier.notify = quiesce_powerdown_req;
+    qn.event = event;
+
+    qemu_register_powerdown_notifier(&qn.notifier);
+
+    return 0;
+}
+
+static void quiesce_class_init(ObjectClass *klass, void *data)
+{
+    SCLPEventClass *k = SCLP_EVENT_CLASS(klass);
+
+    k->init = quiesce_init;
+
+    k->get_send_mask = send_mask;
+    k->get_receive_mask = receive_mask;
+    k->event_type = event_type;
+    k->read_event_data = read_event_data;
+    k->write_event_data = NULL;
+}
+
+static TypeInfo sclp_quiesce_info = {
+    .name          = "sclpquiesce",
+    .parent        = TYPE_SCLP_EVENT,
+    .instance_size = sizeof(SCLPEvent),
+    .class_init    = quiesce_class_init,
+    .class_size    = sizeof(SCLPEventClass),
+};
+
+static void register_types(void)
+{
+    type_register_static(&sclp_quiesce_info);
+}
+
+type_init(register_types)