Merge tag 'block-pull-request' of https://gitlab.com/stefanha/qemu into staging
[qemu.git] / hw / s390x / tod-kvm.c
1 /*
2 * TOD (Time Of Day) clock - KVM implementation
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 "qapi/error.h"
13 #include "qemu/module.h"
14 #include "sysemu/runstate.h"
15 #include "hw/s390x/tod.h"
16 #include "hw/s390x/pv.h"
17 #include "kvm/kvm_s390x.h"
18
19 static void kvm_s390_get_tod_raw(S390TOD *tod, Error **errp)
20 {
21 int r;
22
23 r = kvm_s390_get_clock_ext(&tod->high, &tod->low);
24 if (r == -ENXIO) {
25 r = kvm_s390_get_clock(&tod->high, &tod->low);
26 }
27 if (r) {
28 error_setg(errp, "Unable to get KVM guest TOD clock: %s",
29 strerror(-r));
30 }
31 }
32
33 static void kvm_s390_tod_get(const S390TODState *td, S390TOD *tod, Error **errp)
34 {
35 if (td->stopped) {
36 *tod = td->base;
37 return;
38 }
39
40 kvm_s390_get_tod_raw(tod, errp);
41 }
42
43 static void kvm_s390_set_tod_raw(const S390TOD *tod, Error **errp)
44 {
45 int r;
46
47 r = kvm_s390_set_clock_ext(tod->high, tod->low);
48 if (r == -ENXIO) {
49 r = kvm_s390_set_clock(tod->high, tod->low);
50 }
51 if (r) {
52 error_setg(errp, "Unable to set KVM guest TOD clock: %s",
53 strerror(-r));
54 }
55 }
56
57 static void kvm_s390_tod_set(S390TODState *td, const S390TOD *tod, Error **errp)
58 {
59 Error *local_err = NULL;
60
61 /*
62 * Somebody (e.g. migration) set the TOD. We'll store it into KVM to
63 * properly detect errors now but take a look at the runstate to decide
64 * whether really to keep the tod running. E.g. during migration, this
65 * is the point where we want to stop the initially running TOD to fire
66 * it back up when actually starting the migrated guest.
67 */
68 kvm_s390_set_tod_raw(tod, &local_err);
69 if (local_err) {
70 error_propagate(errp, local_err);
71 return;
72 }
73
74 if (runstate_is_running()) {
75 td->stopped = false;
76 } else {
77 td->stopped = true;
78 td->base = *tod;
79 }
80 }
81
82 static void kvm_s390_tod_vm_state_change(void *opaque, bool running,
83 RunState state)
84 {
85 S390TODState *td = opaque;
86 Error *local_err = NULL;
87
88 /*
89 * Under PV, the clock is under ultravisor control, hence we cannot restore
90 * it on resume.
91 */
92 if (s390_is_pv()) {
93 return;
94 }
95
96 if (running && td->stopped) {
97 /* Set the old TOD when running the VM - start the TOD clock. */
98 kvm_s390_set_tod_raw(&td->base, &local_err);
99 if (local_err) {
100 warn_report_err(local_err);
101 }
102 /* Treat errors like the TOD was running all the time. */
103 td->stopped = false;
104 } else if (!running && !td->stopped) {
105 /* Store the TOD when stopping the VM - stop the TOD clock. */
106 kvm_s390_get_tod_raw(&td->base, &local_err);
107 if (local_err) {
108 /* Keep the TOD running in case we could not back it up. */
109 warn_report_err(local_err);
110 } else {
111 td->stopped = true;
112 }
113 }
114 }
115
116 static void kvm_s390_tod_realize(DeviceState *dev, Error **errp)
117 {
118 S390TODState *td = S390_TOD(dev);
119 S390TODClass *tdc = S390_TOD_GET_CLASS(td);
120 Error *local_err = NULL;
121
122 tdc->parent_realize(dev, &local_err);
123 if (local_err) {
124 error_propagate(errp, local_err);
125 return;
126 }
127
128 /*
129 * We need to know when the VM gets started/stopped to start/stop the TOD.
130 * As we can never have more than one TOD instance (and that will never be
131 * removed), registering here and never unregistering is good enough.
132 */
133 qemu_add_vm_change_state_handler(kvm_s390_tod_vm_state_change, td);
134 }
135
136 static void kvm_s390_tod_class_init(ObjectClass *oc, void *data)
137 {
138 S390TODClass *tdc = S390_TOD_CLASS(oc);
139
140 device_class_set_parent_realize(DEVICE_CLASS(oc), kvm_s390_tod_realize,
141 &tdc->parent_realize);
142 tdc->get = kvm_s390_tod_get;
143 tdc->set = kvm_s390_tod_set;
144 }
145
146 static void kvm_s390_tod_init(Object *obj)
147 {
148 S390TODState *td = S390_TOD(obj);
149
150 /*
151 * The TOD is initially running (value stored in KVM). Avoid needless
152 * loading/storing of the TOD when starting a simple VM, so let it
153 * run although the (never started) VM is stopped. For migration, we
154 * will properly set the TOD later.
155 */
156 td->stopped = false;
157 }
158
159 static const TypeInfo kvm_s390_tod_info = {
160 .name = TYPE_KVM_S390_TOD,
161 .parent = TYPE_S390_TOD,
162 .instance_size = sizeof(S390TODState),
163 .instance_init = kvm_s390_tod_init,
164 .class_init = kvm_s390_tod_class_init,
165 .class_size = sizeof(S390TODClass),
166 };
167
168 static void register_types(void)
169 {
170 type_register_static(&kvm_s390_tod_info);
171 }
172 type_init(register_types);