xref: /openbmc/qemu/hw/s390x/tod.c (revision 37677d7d)
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/register.h"
18 
19 void s390_init_tod(void)
20 {
21     Object *obj;
22 
23     if (kvm_enabled()) {
24         obj = object_new(TYPE_KVM_S390_TOD);
25     } else {
26         obj = object_new(TYPE_QEMU_S390_TOD);
27     }
28     object_property_add_child(qdev_get_machine(), TYPE_S390_TOD, obj, NULL);
29     object_unref(obj);
30 
31     qdev_init_nofail(DEVICE(obj));
32 }
33 
34 S390TODState *s390_get_todstate(void)
35 {
36     static S390TODState *ts;
37 
38     if (!ts) {
39         ts = S390_TOD(object_resolve_path_type("", TYPE_S390_TOD, NULL));
40     }
41 
42     return ts;
43 }
44 
45 #define S390_TOD_CLOCK_VALUE_MISSING    0x00
46 #define S390_TOD_CLOCK_VALUE_PRESENT    0x01
47 
48 static void s390_tod_save(QEMUFile *f, void *opaque)
49 {
50     S390TODState *td = opaque;
51     S390TODClass *tdc = S390_TOD_GET_CLASS(td);
52     Error *err = NULL;
53     S390TOD tod;
54 
55     tdc->get(td, &tod, &err);
56     if (err) {
57         warn_report_err(err);
58         error_printf("Guest clock will not be migrated "
59                      "which could cause the guest to hang.");
60         qemu_put_byte(f, S390_TOD_CLOCK_VALUE_MISSING);
61         return;
62     }
63 
64     qemu_put_byte(f, S390_TOD_CLOCK_VALUE_PRESENT);
65     qemu_put_byte(f, tod.high);
66     qemu_put_be64(f, tod.low);
67 }
68 
69 static int s390_tod_load(QEMUFile *f, void *opaque, int version_id)
70 {
71     S390TODState *td = opaque;
72     S390TODClass *tdc = S390_TOD_GET_CLASS(td);
73     Error *err = NULL;
74     S390TOD tod;
75 
76     if (qemu_get_byte(f) == S390_TOD_CLOCK_VALUE_MISSING) {
77         warn_report("Guest clock was not migrated. This could "
78                     "cause the guest to hang.");
79         return 0;
80     }
81 
82     tod.high = qemu_get_byte(f);
83     tod.low = qemu_get_be64(f);
84 
85     tdc->set(td, &tod, &err);
86     if (err) {
87         error_report_err(err);
88         return -1;
89     }
90     return 0;
91 }
92 
93 static SaveVMHandlers savevm_tod = {
94     .save_state = s390_tod_save,
95     .load_state = s390_tod_load,
96 };
97 
98 static void s390_tod_realize(DeviceState *dev, Error **errp)
99 {
100     S390TODState *td = S390_TOD(dev);
101 
102     /* Legacy migration interface */
103     register_savevm_live(NULL, "todclock", 0, 1, &savevm_tod, td);
104 }
105 
106 static void s390_tod_class_init(ObjectClass *oc, void *data)
107 {
108     DeviceClass *dc = DEVICE_CLASS(oc);
109 
110     dc->desc = "TOD (Time Of Day) Clock";
111     dc->realize = s390_tod_realize;
112     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
113 
114     /* We only have one TOD clock in the system attached to the machine */
115     dc->user_creatable = false;
116 }
117 
118 static TypeInfo s390_tod_info = {
119     .name = TYPE_S390_TOD,
120     .parent = TYPE_DEVICE,
121     .instance_size = sizeof(S390TODState),
122     .class_init = s390_tod_class_init,
123     .class_size = sizeof(S390TODClass),
124     .abstract = true,
125 };
126 
127 static void register_types(void)
128 {
129     type_register_static(&s390_tod_info);
130 }
131 type_init(register_types);
132