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12#include "qemu/osdep.h"
13#include "qapi/error.h"
14#include "qemu/iov.h"
15#include "qemu/module.h"
16#include "hw/qdev.h"
17#include "hw/virtio/virtio.h"
18#include "hw/virtio/virtio-rng.h"
19#include "sysemu/rng.h"
20#include "qom/object_interfaces.h"
21#include "trace.h"
22
23static bool is_guest_ready(VirtIORNG *vrng)
24{
25 VirtIODevice *vdev = VIRTIO_DEVICE(vrng);
26 if (virtio_queue_ready(vrng->vq)
27 && (vdev->status & VIRTIO_CONFIG_S_DRIVER_OK)) {
28 return true;
29 }
30 trace_virtio_rng_guest_not_ready(vrng);
31 return false;
32}
33
34static size_t get_request_size(VirtQueue *vq, unsigned quota)
35{
36 unsigned int in, out;
37
38 virtqueue_get_avail_bytes(vq, &in, &out, quota, 0);
39 return in;
40}
41
42static void virtio_rng_process(VirtIORNG *vrng);
43
44
45static void chr_read(void *opaque, const void *buf, size_t size)
46{
47 VirtIORNG *vrng = opaque;
48 VirtIODevice *vdev = VIRTIO_DEVICE(vrng);
49 VirtQueueElement *elem;
50 size_t len;
51 int offset;
52
53 if (!is_guest_ready(vrng)) {
54 return;
55 }
56
57
58
59
60
61 if (!runstate_check(RUN_STATE_RUNNING)) {
62 trace_virtio_rng_cpu_is_stopped(vrng, size);
63 return;
64 }
65
66 vrng->quota_remaining -= size;
67
68 offset = 0;
69 while (offset < size) {
70 elem = virtqueue_pop(vrng->vq, sizeof(VirtQueueElement));
71 if (!elem) {
72 break;
73 }
74 trace_virtio_rng_popped(vrng);
75 len = iov_from_buf(elem->in_sg, elem->in_num,
76 0, buf + offset, size - offset);
77 offset += len;
78
79 virtqueue_push(vrng->vq, elem, len);
80 trace_virtio_rng_pushed(vrng, len);
81 g_free(elem);
82 }
83 virtio_notify(vdev, vrng->vq);
84
85 if (!virtio_queue_empty(vrng->vq)) {
86
87
88
89 virtio_rng_process(vrng);
90 }
91}
92
93static void virtio_rng_process(VirtIORNG *vrng)
94{
95 size_t size;
96 unsigned quota;
97
98 if (!is_guest_ready(vrng)) {
99 return;
100 }
101
102 if (vrng->activate_timer) {
103 timer_mod(vrng->rate_limit_timer,
104 qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + vrng->conf.period_ms);
105 vrng->activate_timer = false;
106 }
107
108 if (vrng->quota_remaining < 0) {
109 quota = 0;
110 } else {
111 quota = MIN((uint64_t)vrng->quota_remaining, (uint64_t)UINT32_MAX);
112 }
113 size = get_request_size(vrng->vq, quota);
114
115 trace_virtio_rng_request(vrng, size, quota);
116
117 size = MIN(vrng->quota_remaining, size);
118 if (size) {
119 rng_backend_request_entropy(vrng->rng, size, chr_read, vrng);
120 }
121}
122
123static void handle_input(VirtIODevice *vdev, VirtQueue *vq)
124{
125 VirtIORNG *vrng = VIRTIO_RNG(vdev);
126 virtio_rng_process(vrng);
127}
128
129static uint64_t get_features(VirtIODevice *vdev, uint64_t f, Error **errp)
130{
131 return f;
132}
133
134static void virtio_rng_vm_state_change(void *opaque, int running,
135 RunState state)
136{
137 VirtIORNG *vrng = opaque;
138
139 trace_virtio_rng_vm_state_change(vrng, running, state);
140
141
142
143
144
145
146 if (running && is_guest_ready(vrng)) {
147 virtio_rng_process(vrng);
148 }
149}
150
151static void check_rate_limit(void *opaque)
152{
153 VirtIORNG *vrng = opaque;
154
155 vrng->quota_remaining = vrng->conf.max_bytes;
156 virtio_rng_process(vrng);
157 vrng->activate_timer = true;
158}
159
160static void virtio_rng_set_status(VirtIODevice *vdev, uint8_t status)
161{
162 VirtIORNG *vrng = VIRTIO_RNG(vdev);
163
164 if (!vdev->vm_running) {
165 return;
166 }
167 vdev->status = status;
168
169
170 virtio_rng_process(vrng);
171}
172
173static void virtio_rng_device_realize(DeviceState *dev, Error **errp)
174{
175 VirtIODevice *vdev = VIRTIO_DEVICE(dev);
176 VirtIORNG *vrng = VIRTIO_RNG(dev);
177 Error *local_err = NULL;
178
179 if (vrng->conf.period_ms <= 0) {
180 error_setg(errp, "'period' parameter expects a positive integer");
181 return;
182 }
183
184
185
186 if (vrng->conf.max_bytes > INT64_MAX) {
187 error_setg(errp, "'max-bytes' parameter must be non-negative, "
188 "and less than 2^63");
189 return;
190 }
191
192 if (vrng->conf.rng == NULL) {
193 vrng->conf.default_backend = RNG_RANDOM(object_new(TYPE_RNG_RANDOM));
194
195 user_creatable_complete(USER_CREATABLE(vrng->conf.default_backend),
196 &local_err);
197 if (local_err) {
198 error_propagate(errp, local_err);
199 object_unref(OBJECT(vrng->conf.default_backend));
200 return;
201 }
202
203 object_property_add_child(OBJECT(dev),
204 "default-backend",
205 OBJECT(vrng->conf.default_backend),
206 NULL);
207
208
209 object_unref(OBJECT(vrng->conf.default_backend));
210
211 object_property_set_link(OBJECT(dev),
212 OBJECT(vrng->conf.default_backend),
213 "rng", NULL);
214 }
215
216 vrng->rng = vrng->conf.rng;
217 if (vrng->rng == NULL) {
218 error_setg(errp, "'rng' parameter expects a valid object");
219 return;
220 }
221
222 virtio_init(vdev, "virtio-rng", VIRTIO_ID_RNG, 0);
223
224 vrng->vq = virtio_add_queue(vdev, 8, handle_input);
225 vrng->quota_remaining = vrng->conf.max_bytes;
226 vrng->rate_limit_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL,
227 check_rate_limit, vrng);
228 vrng->activate_timer = true;
229
230 vrng->vmstate = qemu_add_vm_change_state_handler(virtio_rng_vm_state_change,
231 vrng);
232}
233
234static void virtio_rng_device_unrealize(DeviceState *dev, Error **errp)
235{
236 VirtIODevice *vdev = VIRTIO_DEVICE(dev);
237 VirtIORNG *vrng = VIRTIO_RNG(dev);
238
239 qemu_del_vm_change_state_handler(vrng->vmstate);
240 timer_del(vrng->rate_limit_timer);
241 timer_free(vrng->rate_limit_timer);
242 virtio_cleanup(vdev);
243}
244
245static const VMStateDescription vmstate_virtio_rng = {
246 .name = "virtio-rng",
247 .minimum_version_id = 1,
248 .version_id = 1,
249 .fields = (VMStateField[]) {
250 VMSTATE_VIRTIO_DEVICE,
251 VMSTATE_END_OF_LIST()
252 },
253};
254
255static Property virtio_rng_properties[] = {
256
257
258
259
260
261 DEFINE_PROP_UINT64("max-bytes", VirtIORNG, conf.max_bytes, INT64_MAX),
262 DEFINE_PROP_UINT32("period", VirtIORNG, conf.period_ms, 1 << 16),
263 DEFINE_PROP_LINK("rng", VirtIORNG, conf.rng, TYPE_RNG_BACKEND, RngBackend *),
264 DEFINE_PROP_END_OF_LIST(),
265};
266
267static void virtio_rng_class_init(ObjectClass *klass, void *data)
268{
269 DeviceClass *dc = DEVICE_CLASS(klass);
270 VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
271
272 dc->props = virtio_rng_properties;
273 dc->vmsd = &vmstate_virtio_rng;
274 set_bit(DEVICE_CATEGORY_MISC, dc->categories);
275 vdc->realize = virtio_rng_device_realize;
276 vdc->unrealize = virtio_rng_device_unrealize;
277 vdc->get_features = get_features;
278 vdc->set_status = virtio_rng_set_status;
279}
280
281static const TypeInfo virtio_rng_info = {
282 .name = TYPE_VIRTIO_RNG,
283 .parent = TYPE_VIRTIO_DEVICE,
284 .instance_size = sizeof(VirtIORNG),
285 .class_init = virtio_rng_class_init,
286};
287
288static void virtio_register_types(void)
289{
290 type_register_static(&virtio_rng_info);
291}
292
293type_init(virtio_register_types)
294