hw/s390x/tod.c

   1 /*
   2  * TOD (Time Of Day) clock
   3  *
   4  * Copyright 2018 Red Hat, Inc.
   5  * Author(s): David Hildenbrand <david@redhat.com>
   6  *
   7  * This work is licensed under the terms of the GNU GPL, version 2 or later.
   8  * See the COPYING file in the top-level directory.
   9  */
  10
  11 #include "qemu/osdep.h"
  12 #include "hw/s390x/tod.h"
  13 #include "qapi/error.h"
  14 #include "qemu/error-report.h"
  15 #include "qemu/module.h"
  16 #include "sysemu/kvm.h"
  17 #include "migration/qemu-file-types.h"
  18 #include "migration/register.h"
  19
  20 void s390_init_tod(void)
  21 {
  22     Object *obj;
  23
  24     if (kvm_enabled()) {
  25         obj = object_new(TYPE_KVM_S390_TOD);
  26     } else {
  27         obj = object_new(TYPE_QEMU_S390_TOD);
  28     }
  29     object_property_add_child(qdev_get_machine(), TYPE_S390_TOD, obj);
  30     object_unref(obj);
  31
  32     qdev_init_nofail(DEVICE(obj));
  33 }
  34
  35 S390TODState *s390_get_todstate(void)
  36 {
  37     static S390TODState *ts;
  38
  39     if (!ts) {
  40         ts = S390_TOD(object_resolve_path_type("", TYPE_S390_TOD, NULL));
  41     }
  42
  43     return ts;
  44 }
  45
  46 #define S390_TOD_CLOCK_VALUE_MISSING    0x00
  47 #define S390_TOD_CLOCK_VALUE_PRESENT    0x01
  48
  49 static void s390_tod_save(QEMUFile *f, void *opaque)
  50 {
  51     S390TODState *td = opaque;
  52     S390TODClass *tdc = S390_TOD_GET_CLASS(td);
  53     Error *err = NULL;
  54     S390TOD tod;
  55
  56     tdc->get(td, &tod, &err);
  57     if (err) {
  58         warn_report_err(err);
  59         error_printf("Guest clock will not be migrated "
  60                      "which could cause the guest to hang.");
  61         qemu_put_byte(f, S390_TOD_CLOCK_VALUE_MISSING);
  62         return;
  63     }
  64
  65     qemu_put_byte(f, S390_TOD_CLOCK_VALUE_PRESENT);
  66     qemu_put_byte(f, tod.high);
  67     qemu_put_be64(f, tod.low);
  68 }
  69
  70 static int s390_tod_load(QEMUFile *f, void *opaque, int version_id)
  71 {
  72     S390TODState *td = opaque;
  73     S390TODClass *tdc = S390_TOD_GET_CLASS(td);
  74     Error *err = NULL;
  75     S390TOD tod;
  76
  77     if (qemu_get_byte(f) == S390_TOD_CLOCK_VALUE_MISSING) {
  78         warn_report("Guest clock was not migrated. This could "
  79                     "cause the guest to hang.");
  80         return 0;
  81     }
  82
  83     tod.high = qemu_get_byte(f);
  84     tod.low = qemu_get_be64(f);
  85
  86     tdc->set(td, &tod, &err);
  87     if (err) {
  88         error_report_err(err);
  89         return -1;
  90     }
  91     return 0;
  92 }
  93
  94 static SaveVMHandlers savevm_tod = {
  95     .save_state = s390_tod_save,
  96     .load_state = s390_tod_load,
  97 };
  98
  99 static void s390_tod_realize(DeviceState *dev, Error **errp)
 100 {
 101     S390TODState *td = S390_TOD(dev);
 102
 103     /* Legacy migration interface */
 104     register_savevm_live("todclock", 0, 1, &savevm_tod, td);
 105 }
 106
 107 static void s390_tod_class_init(ObjectClass *oc, void *data)
 108 {
 109     DeviceClass *dc = DEVICE_CLASS(oc);
 110
 111     dc->desc = "TOD (Time Of Day) Clock";
 112     dc->realize = s390_tod_realize;
 113     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
 114
 115     /* We only have one TOD clock in the system attached to the machine */
 116     dc->user_creatable = false;
 117 }
 118
 119 static TypeInfo s390_tod_info = {
 120     .name = TYPE_S390_TOD,
 121     .parent = TYPE_DEVICE,
 122     .instance_size = sizeof(S390TODState),
 123     .class_init = s390_tod_class_init,
 124     .class_size = sizeof(S390TODClass),
 125     .abstract = true,
 126 };
 127
 128 static void register_types(void)
 129 {
 130     type_register_static(&s390_tod_info);
 131 }
 132 type_init(register_types);