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Commit | Line | Data |
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16c915ba AS |
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 | ||
1de7afc9 | 12 | #include "qemu/iov.h" |
83c9f4ca | 13 | #include "hw/qdev.h" |
b4a42f81 | 14 | #include "qapi/qmp/qerror.h" |
0d09e41a PB |
15 | #include "hw/virtio/virtio.h" |
16 | #include "hw/virtio/virtio-rng.h" | |
dccfcd0e | 17 | #include "sysemu/rng.h" |
57d3e1b3 | 18 | #include "qom/object_interfaces.h" |
16c915ba | 19 | |
16c915ba AS |
20 | static bool is_guest_ready(VirtIORNG *vrng) |
21 | { | |
611aa333 | 22 | VirtIODevice *vdev = VIRTIO_DEVICE(vrng); |
16c915ba | 23 | if (virtio_queue_ready(vrng->vq) |
611aa333 | 24 | && (vdev->status & VIRTIO_CONFIG_S_DRIVER_OK)) { |
16c915ba AS |
25 | return true; |
26 | } | |
27 | return false; | |
28 | } | |
29 | ||
e1f7b481 | 30 | static size_t get_request_size(VirtQueue *vq, unsigned quota) |
16c915ba | 31 | { |
14417039 | 32 | unsigned int in, out; |
16c915ba | 33 | |
e1f7b481 | 34 | virtqueue_get_avail_bytes(vq, &in, &out, quota, 0); |
14417039 | 35 | return in; |
16c915ba AS |
36 | } |
37 | ||
904d6f58 AL |
38 | static void virtio_rng_process(VirtIORNG *vrng); |
39 | ||
16c915ba AS |
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; | |
611aa333 | 44 | VirtIODevice *vdev = VIRTIO_DEVICE(vrng); |
14417039 | 45 | VirtQueueElement elem; |
16c915ba AS |
46 | size_t len; |
47 | int offset; | |
48 | ||
49 | if (!is_guest_ready(vrng)) { | |
50 | return; | |
51 | } | |
52 | ||
904d6f58 AL |
53 | vrng->quota_remaining -= size; |
54 | ||
16c915ba AS |
55 | offset = 0; |
56 | while (offset < size) { | |
14417039 | 57 | if (!virtqueue_pop(vrng->vq, &elem)) { |
16c915ba AS |
58 | break; |
59 | } | |
14417039 | 60 | len = iov_from_buf(elem.in_sg, elem.in_num, |
16c915ba AS |
61 | 0, buf + offset, size - offset); |
62 | offset += len; | |
63 | ||
14417039 | 64 | virtqueue_push(vrng->vq, &elem, len); |
16c915ba | 65 | } |
611aa333 | 66 | virtio_notify(vdev, vrng->vq); |
16c915ba AS |
67 | } |
68 | ||
904d6f58 | 69 | static void virtio_rng_process(VirtIORNG *vrng) |
16c915ba | 70 | { |
14417039 | 71 | size_t size; |
e1f7b481 | 72 | unsigned quota; |
904d6f58 AL |
73 | |
74 | if (!is_guest_ready(vrng)) { | |
75 | return; | |
76 | } | |
16c915ba | 77 | |
e1f7b481 MT |
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); | |
904d6f58 | 84 | size = MIN(vrng->quota_remaining, size); |
14417039 | 85 | if (size) { |
16c915ba AS |
86 | rng_backend_request_entropy(vrng->rng, size, chr_read, vrng); |
87 | } | |
88 | } | |
89 | ||
904d6f58 AL |
90 | static void handle_input(VirtIODevice *vdev, VirtQueue *vq) |
91 | { | |
611aa333 | 92 | VirtIORNG *vrng = VIRTIO_RNG(vdev); |
904d6f58 AL |
93 | virtio_rng_process(vrng); |
94 | } | |
95 | ||
16c915ba AS |
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 | { | |
611aa333 | 103 | VirtIODevice *vdev = opaque; |
16c915ba | 104 | |
611aa333 | 105 | virtio_save(vdev, f); |
16c915ba AS |
106 | } |
107 | ||
108 | static int virtio_rng_load(QEMUFile *f, void *opaque, int version_id) | |
109 | { | |
16c915ba AS |
110 | if (version_id != 1) { |
111 | return -EINVAL; | |
112 | } | |
3902d49e GK |
113 | return virtio_load(VIRTIO_DEVICE(opaque), f, version_id); |
114 | } | |
16c915ba | 115 | |
3902d49e GK |
116 | static int virtio_rng_load_device(VirtIODevice *vdev, QEMUFile *f, |
117 | int version_id) | |
118 | { | |
904d6f58 | 119 | /* We may have an element ready but couldn't process it due to a quota |
42015c9a AS |
120 | * limit. Make sure to try again after live migration when the quota may |
121 | * have been reset. | |
122 | */ | |
3902d49e | 123 | virtio_rng_process(VIRTIO_RNG(vdev)); |
904d6f58 | 124 | |
16c915ba AS |
125 | return 0; |
126 | } | |
127 | ||
904d6f58 AL |
128 | static void check_rate_limit(void *opaque) |
129 | { | |
611aa333 | 130 | VirtIORNG *vrng = opaque; |
904d6f58 | 131 | |
611aa333 FK |
132 | vrng->quota_remaining = vrng->conf.max_bytes; |
133 | virtio_rng_process(vrng); | |
bc72ad67 AB |
134 | timer_mod(vrng->rate_limit_timer, |
135 | qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + vrng->conf.period_ms); | |
904d6f58 AL |
136 | } |
137 | ||
a8d57dfb | 138 | static void virtio_rng_device_realize(DeviceState *dev, Error **errp) |
16c915ba | 139 | { |
a8d57dfb | 140 | VirtIODevice *vdev = VIRTIO_DEVICE(dev); |
af7671fd | 141 | VirtIORNG *vrng = VIRTIO_RNG(dev); |
16c915ba AS |
142 | Error *local_err = NULL; |
143 | ||
d44bb860 | 144 | if (!vrng->conf.period_ms > 0) { |
a8d57dfb AF |
145 | error_set(errp, QERR_INVALID_PARAMETER_VALUE, "period", |
146 | "a positive number"); | |
147 | return; | |
d44bb860 AK |
148 | } |
149 | ||
46a5a89d FK |
150 | if (vrng->conf.rng == NULL) { |
151 | vrng->conf.default_backend = RNG_RANDOM(object_new(TYPE_RNG_RANDOM)); | |
152 | ||
57d3e1b3 IM |
153 | user_creatable_complete(OBJECT(vrng->conf.default_backend), |
154 | &local_err); | |
155 | if (local_err) { | |
156 | error_propagate(errp, local_err); | |
157 | object_unref(OBJECT(vrng->conf.default_backend)); | |
158 | return; | |
159 | } | |
160 | ||
af7671fd | 161 | object_property_add_child(OBJECT(dev), |
46a5a89d FK |
162 | "default-backend", |
163 | OBJECT(vrng->conf.default_backend), | |
164 | NULL); | |
165 | ||
abdffd1f SH |
166 | /* The child property took a reference, we can safely drop ours now */ |
167 | object_unref(OBJECT(vrng->conf.default_backend)); | |
168 | ||
af7671fd | 169 | object_property_set_link(OBJECT(dev), |
46a5a89d FK |
170 | OBJECT(vrng->conf.default_backend), |
171 | "rng", NULL); | |
6eac8aec | 172 | } |
16c915ba | 173 | |
46a5a89d FK |
174 | virtio_init(vdev, "virtio-rng", VIRTIO_ID_RNG, 0); |
175 | ||
176 | vrng->rng = vrng->conf.rng; | |
16c915ba | 177 | if (vrng->rng == NULL) { |
a8d57dfb AF |
178 | error_set(errp, QERR_INVALID_PARAMETER_VALUE, "rng", "a valid object"); |
179 | return; | |
16c915ba AS |
180 | } |
181 | ||
16c915ba | 182 | vrng->vq = virtio_add_queue(vdev, 8, handle_input); |
6eac8aec | 183 | |
713e8a10 JS |
184 | /* Workaround: Property parsing does not enforce unsigned integers, |
185 | * So this is a hack to reject such numbers. */ | |
186 | if (vrng->conf.max_bytes > INT64_MAX) { | |
187 | error_set(errp, QERR_INVALID_PARAMETER_VALUE, "max-bytes", | |
188 | "a non-negative integer below 2^63"); | |
189 | return; | |
190 | } | |
af1a8ad6 | 191 | vrng->quota_remaining = vrng->conf.max_bytes; |
904d6f58 | 192 | |
bc72ad67 | 193 | vrng->rate_limit_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL, |
904d6f58 AL |
194 | check_rate_limit, vrng); |
195 | ||
bc72ad67 AB |
196 | timer_mod(vrng->rate_limit_timer, |
197 | qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + vrng->conf.period_ms); | |
904d6f58 | 198 | |
af7671fd | 199 | register_savevm(dev, "virtio-rng", -1, 1, virtio_rng_save, |
16c915ba | 200 | virtio_rng_load, vrng); |
6eac8aec FK |
201 | } |
202 | ||
306ec6c3 | 203 | static void virtio_rng_device_unrealize(DeviceState *dev, Error **errp) |
6eac8aec | 204 | { |
306ec6c3 AF |
205 | VirtIODevice *vdev = VIRTIO_DEVICE(dev); |
206 | VirtIORNG *vrng = VIRTIO_RNG(dev); | |
6eac8aec | 207 | |
bc72ad67 AB |
208 | timer_del(vrng->rate_limit_timer); |
209 | timer_free(vrng->rate_limit_timer); | |
306ec6c3 | 210 | unregister_savevm(dev, "virtio-rng", vrng); |
6a1a8cc7 | 211 | virtio_cleanup(vdev); |
6eac8aec FK |
212 | } |
213 | ||
214 | static Property virtio_rng_properties[] = { | |
215 | DEFINE_VIRTIO_RNG_PROPERTIES(VirtIORNG, conf), | |
216 | DEFINE_PROP_END_OF_LIST(), | |
217 | }; | |
218 | ||
219 | static void virtio_rng_class_init(ObjectClass *klass, void *data) | |
220 | { | |
221 | DeviceClass *dc = DEVICE_CLASS(klass); | |
222 | VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass); | |
a8d57dfb | 223 | |
6eac8aec | 224 | dc->props = virtio_rng_properties; |
125ee0ed | 225 | set_bit(DEVICE_CATEGORY_MISC, dc->categories); |
a8d57dfb | 226 | vdc->realize = virtio_rng_device_realize; |
306ec6c3 | 227 | vdc->unrealize = virtio_rng_device_unrealize; |
6eac8aec | 228 | vdc->get_features = get_features; |
3902d49e | 229 | vdc->load = virtio_rng_load_device; |
6eac8aec FK |
230 | } |
231 | ||
232 | static void virtio_rng_initfn(Object *obj) | |
233 | { | |
234 | VirtIORNG *vrng = VIRTIO_RNG(obj); | |
235 | ||
236 | object_property_add_link(obj, "rng", TYPE_RNG_BACKEND, | |
9561fda8 | 237 | (Object **)&vrng->conf.rng, |
39f72ef9 | 238 | qdev_prop_allow_set_link_before_realize, |
9561fda8 | 239 | OBJ_PROP_LINK_UNREF_ON_RELEASE, NULL); |
6eac8aec FK |
240 | } |
241 | ||
242 | static const TypeInfo virtio_rng_info = { | |
243 | .name = TYPE_VIRTIO_RNG, | |
244 | .parent = TYPE_VIRTIO_DEVICE, | |
245 | .instance_size = sizeof(VirtIORNG), | |
246 | .instance_init = virtio_rng_initfn, | |
247 | .class_init = virtio_rng_class_init, | |
248 | }; | |
249 | ||
250 | static void virtio_register_types(void) | |
251 | { | |
252 | type_register_static(&virtio_rng_info); | |
253 | } | |
254 | ||
255 | type_init(virtio_register_types) |