qom: Add check() argument to object_property_add_link()
[qemu.git] / hw / virtio / virtio-rng.c
1 /*
2 * A virtio device implementing a hardware random number generator.
3 *
4 * Copyright 2012 Red Hat, Inc.
5 * Copyright 2012 Amit Shah <amit.shah@redhat.com>
6 *
7 * This work is licensed under the terms of the GNU GPL, version 2 or
8 * (at your option) any later version. See the COPYING file in the
9 * top-level directory.
10 */
11
12 #include "qemu/iov.h"
13 #include "hw/qdev.h"
14 #include "qapi/qmp/qerror.h"
15 #include "hw/virtio/virtio.h"
16 #include "hw/virtio/virtio-rng.h"
17 #include "sysemu/rng.h"
18 #include "qom/object_interfaces.h"
19
20 static bool is_guest_ready(VirtIORNG *vrng)
21 {
22 VirtIODevice *vdev = VIRTIO_DEVICE(vrng);
23 if (virtio_queue_ready(vrng->vq)
24 && (vdev->status & VIRTIO_CONFIG_S_DRIVER_OK)) {
25 return true;
26 }
27 return false;
28 }
29
30 static size_t get_request_size(VirtQueue *vq, unsigned quota)
31 {
32 unsigned int in, out;
33
34 virtqueue_get_avail_bytes(vq, &in, &out, quota, 0);
35 return in;
36 }
37
38 static void virtio_rng_process(VirtIORNG *vrng);
39
40 /* Send data from a char device over to the guest */
41 static void chr_read(void *opaque, const void *buf, size_t size)
42 {
43 VirtIORNG *vrng = opaque;
44 VirtIODevice *vdev = VIRTIO_DEVICE(vrng);
45 VirtQueueElement elem;
46 size_t len;
47 int offset;
48
49 if (!is_guest_ready(vrng)) {
50 return;
51 }
52
53 vrng->quota_remaining -= size;
54
55 offset = 0;
56 while (offset < size) {
57 if (!virtqueue_pop(vrng->vq, &elem)) {
58 break;
59 }
60 len = iov_from_buf(elem.in_sg, elem.in_num,
61 0, buf + offset, size - offset);
62 offset += len;
63
64 virtqueue_push(vrng->vq, &elem, len);
65 }
66 virtio_notify(vdev, vrng->vq);
67 }
68
69 static void virtio_rng_process(VirtIORNG *vrng)
70 {
71 size_t size;
72 unsigned quota;
73
74 if (!is_guest_ready(vrng)) {
75 return;
76 }
77
78 if (vrng->quota_remaining < 0) {
79 quota = 0;
80 } else {
81 quota = MIN((uint64_t)vrng->quota_remaining, (uint64_t)UINT32_MAX);
82 }
83 size = get_request_size(vrng->vq, quota);
84 size = MIN(vrng->quota_remaining, size);
85 if (size) {
86 rng_backend_request_entropy(vrng->rng, size, chr_read, vrng);
87 }
88 }
89
90 static void handle_input(VirtIODevice *vdev, VirtQueue *vq)
91 {
92 VirtIORNG *vrng = VIRTIO_RNG(vdev);
93 virtio_rng_process(vrng);
94 }
95
96 static uint32_t get_features(VirtIODevice *vdev, uint32_t f)
97 {
98 return f;
99 }
100
101 static void virtio_rng_save(QEMUFile *f, void *opaque)
102 {
103 VirtIODevice *vdev = opaque;
104
105 virtio_save(vdev, f);
106 }
107
108 static int virtio_rng_load(QEMUFile *f, void *opaque, int version_id)
109 {
110 VirtIORNG *vrng = opaque;
111 VirtIODevice *vdev = VIRTIO_DEVICE(vrng);
112
113 if (version_id != 1) {
114 return -EINVAL;
115 }
116 virtio_load(vdev, f);
117
118 /* We may have an element ready but couldn't process it due to a quota
119 * limit. Make sure to try again after live migration when the quota may
120 * have been reset.
121 */
122 virtio_rng_process(vrng);
123
124 return 0;
125 }
126
127 static void check_rate_limit(void *opaque)
128 {
129 VirtIORNG *vrng = opaque;
130
131 vrng->quota_remaining = vrng->conf.max_bytes;
132 virtio_rng_process(vrng);
133 timer_mod(vrng->rate_limit_timer,
134 qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + vrng->conf.period_ms);
135 }
136
137 static void virtio_rng_device_realize(DeviceState *dev, Error **errp)
138 {
139 VirtIODevice *vdev = VIRTIO_DEVICE(dev);
140 VirtIORNG *vrng = VIRTIO_RNG(dev);
141 Error *local_err = NULL;
142
143 if (!vrng->conf.period_ms > 0) {
144 error_set(errp, QERR_INVALID_PARAMETER_VALUE, "period",
145 "a positive number");
146 return;
147 }
148
149 if (vrng->conf.rng == NULL) {
150 vrng->conf.default_backend = RNG_RANDOM(object_new(TYPE_RNG_RANDOM));
151
152 user_creatable_complete(OBJECT(vrng->conf.default_backend),
153 &local_err);
154 if (local_err) {
155 error_propagate(errp, local_err);
156 object_unref(OBJECT(vrng->conf.default_backend));
157 return;
158 }
159
160 object_property_add_child(OBJECT(dev),
161 "default-backend",
162 OBJECT(vrng->conf.default_backend),
163 NULL);
164
165 object_property_set_link(OBJECT(dev),
166 OBJECT(vrng->conf.default_backend),
167 "rng", NULL);
168 }
169
170 virtio_init(vdev, "virtio-rng", VIRTIO_ID_RNG, 0);
171
172 vrng->rng = vrng->conf.rng;
173 if (vrng->rng == NULL) {
174 error_set(errp, QERR_INVALID_PARAMETER_VALUE, "rng", "a valid object");
175 return;
176 }
177
178 vrng->vq = virtio_add_queue(vdev, 8, handle_input);
179
180 assert(vrng->conf.max_bytes <= INT64_MAX);
181 vrng->quota_remaining = vrng->conf.max_bytes;
182
183 vrng->rate_limit_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL,
184 check_rate_limit, vrng);
185
186 timer_mod(vrng->rate_limit_timer,
187 qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + vrng->conf.period_ms);
188
189 register_savevm(dev, "virtio-rng", -1, 1, virtio_rng_save,
190 virtio_rng_load, vrng);
191 }
192
193 static void virtio_rng_device_unrealize(DeviceState *dev, Error **errp)
194 {
195 VirtIODevice *vdev = VIRTIO_DEVICE(dev);
196 VirtIORNG *vrng = VIRTIO_RNG(dev);
197
198 timer_del(vrng->rate_limit_timer);
199 timer_free(vrng->rate_limit_timer);
200 unregister_savevm(dev, "virtio-rng", vrng);
201 virtio_cleanup(vdev);
202 }
203
204 static Property virtio_rng_properties[] = {
205 DEFINE_VIRTIO_RNG_PROPERTIES(VirtIORNG, conf),
206 DEFINE_PROP_END_OF_LIST(),
207 };
208
209 static void virtio_rng_class_init(ObjectClass *klass, void *data)
210 {
211 DeviceClass *dc = DEVICE_CLASS(klass);
212 VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
213
214 dc->props = virtio_rng_properties;
215 set_bit(DEVICE_CATEGORY_MISC, dc->categories);
216 vdc->realize = virtio_rng_device_realize;
217 vdc->unrealize = virtio_rng_device_unrealize;
218 vdc->get_features = get_features;
219 }
220
221 static void virtio_rng_initfn(Object *obj)
222 {
223 VirtIORNG *vrng = VIRTIO_RNG(obj);
224
225 object_property_add_link(obj, "rng", TYPE_RNG_BACKEND,
226 (Object **)&vrng->conf.rng,
227 qdev_prop_allow_set_link_before_realize,
228 OBJ_PROP_LINK_UNREF_ON_RELEASE, NULL);
229 }
230
231 static const TypeInfo virtio_rng_info = {
232 .name = TYPE_VIRTIO_RNG,
233 .parent = TYPE_VIRTIO_DEVICE,
234 .instance_size = sizeof(VirtIORNG),
235 .instance_init = virtio_rng_initfn,
236 .class_init = virtio_rng_class_init,
237 };
238
239 static void virtio_register_types(void)
240 {
241 type_register_static(&virtio_rng_info);
242 }
243
244 type_init(virtio_register_types)