xref: /openbmc/qemu/hw/s390x/tod.c (revision 39337f12)
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_realize(DEVICE(obj), NULL, &error_fatal);
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);
133