xref: /openbmc/qemu/hw/s390x/tod.c (revision 073d9f2c)
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 "sysemu/kvm.h"
16 #include "migration/register.h"
17 
18 void s390_init_tod(void)
19 {
20     Object *obj;
21 
22     if (kvm_enabled()) {
23         obj = object_new(TYPE_KVM_S390_TOD);
24     } else {
25         obj = object_new(TYPE_QEMU_S390_TOD);
26     }
27     object_property_add_child(qdev_get_machine(), TYPE_S390_TOD, obj, NULL);
28     object_unref(obj);
29 
30     qdev_init_nofail(DEVICE(obj));
31 }
32 
33 S390TODState *s390_get_todstate(void)
34 {
35     static S390TODState *ts;
36 
37     if (!ts) {
38         ts = S390_TOD(object_resolve_path_type("", TYPE_S390_TOD, NULL));
39     }
40 
41     return ts;
42 }
43 
44 #define S390_TOD_CLOCK_VALUE_MISSING    0x00
45 #define S390_TOD_CLOCK_VALUE_PRESENT    0x01
46 
47 static void s390_tod_save(QEMUFile *f, void *opaque)
48 {
49     S390TODState *td = opaque;
50     S390TODClass *tdc = S390_TOD_GET_CLASS(td);
51     Error *err = NULL;
52     S390TOD tod;
53 
54     tdc->get(td, &tod, &err);
55     if (err) {
56         warn_report_err(err);
57         error_printf("Guest clock will not be migrated "
58                      "which could cause the guest to hang.");
59         qemu_put_byte(f, S390_TOD_CLOCK_VALUE_MISSING);
60         return;
61     }
62 
63     qemu_put_byte(f, S390_TOD_CLOCK_VALUE_PRESENT);
64     qemu_put_byte(f, tod.high);
65     qemu_put_be64(f, tod.low);
66 }
67 
68 static int s390_tod_load(QEMUFile *f, void *opaque, int version_id)
69 {
70     S390TODState *td = opaque;
71     S390TODClass *tdc = S390_TOD_GET_CLASS(td);
72     Error *err = NULL;
73     S390TOD tod;
74 
75     if (qemu_get_byte(f) == S390_TOD_CLOCK_VALUE_MISSING) {
76         warn_report("Guest clock was not migrated. This could "
77                     "cause the guest to hang.");
78         return 0;
79     }
80 
81     tod.high = qemu_get_byte(f);
82     tod.low = qemu_get_be64(f);
83 
84     tdc->set(td, &tod, &err);
85     if (err) {
86         error_report_err(err);
87         return -1;
88     }
89     return 0;
90 }
91 
92 static SaveVMHandlers savevm_tod = {
93     .save_state = s390_tod_save,
94     .load_state = s390_tod_load,
95 };
96 
97 static void s390_tod_realize(DeviceState *dev, Error **errp)
98 {
99     S390TODState *td = S390_TOD(dev);
100 
101     /* Legacy migration interface */
102     register_savevm_live(NULL, "todclock", 0, 1, &savevm_tod, td);
103 }
104 
105 static void s390_tod_class_init(ObjectClass *oc, void *data)
106 {
107     DeviceClass *dc = DEVICE_CLASS(oc);
108 
109     dc->desc = "TOD (Time Of Day) Clock";
110     dc->realize = s390_tod_realize;
111     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
112 
113     /* We only have one TOD clock in the system attached to the machine */
114     dc->user_creatable = false;
115 }
116 
117 static TypeInfo s390_tod_info = {
118     .name = TYPE_S390_TOD,
119     .parent = TYPE_DEVICE,
120     .instance_size = sizeof(S390TODState),
121     .class_init = s390_tod_class_init,
122     .class_size = sizeof(S390TODClass),
123     .abstract = true,
124 };
125 
126 static void register_types(void)
127 {
128     type_register_static(&s390_tod_info);
129 }
130 type_init(register_types);
131