aboutsummaryrefslogtreecommitdiff
path: root/hw/virtio/vhost-user-rng.c
blob: 209ee5bf9acd2bb2d2f191de932d3ce97d35d02a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
/*
 * Vhost-user RNG virtio device
 *
 * Copyright (c) 2021 Mathieu Poirier <mathieu.poirier@linaro.org>
 *
 * Implementation seriously tailored on vhost-user-i2c.c
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 */

#include "qemu/osdep.h"
#include "qapi/error.h"
#include "hw/qdev-properties.h"
#include "hw/virtio/virtio-bus.h"
#include "hw/virtio/vhost-user-rng.h"
#include "qemu/error-report.h"
#include "standard-headers/linux/virtio_ids.h"

static void vu_rng_start(VirtIODevice *vdev)
{
    VHostUserRNG *rng = VHOST_USER_RNG(vdev);
    BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
    int ret;
    int i;

    if (!k->set_guest_notifiers) {
        error_report("binding does not support guest notifiers");
        return;
    }

    ret = vhost_dev_enable_notifiers(&rng->vhost_dev, vdev);
    if (ret < 0) {
        error_report("Error enabling host notifiers: %d", -ret);
        return;
    }

    ret = k->set_guest_notifiers(qbus->parent, rng->vhost_dev.nvqs, true);
    if (ret < 0) {
        error_report("Error binding guest notifier: %d", -ret);
        goto err_host_notifiers;
    }

    rng->vhost_dev.acked_features = vdev->guest_features;
    ret = vhost_dev_start(&rng->vhost_dev, vdev);
    if (ret < 0) {
        error_report("Error starting vhost-user-rng: %d", -ret);
        goto err_guest_notifiers;
    }

    /*
     * guest_notifier_mask/pending not used yet, so just unmask
     * everything here. virtio-pci will do the right thing by
     * enabling/disabling irqfd.
     */
    for (i = 0; i < rng->vhost_dev.nvqs; i++) {
        vhost_virtqueue_mask(&rng->vhost_dev, vdev, i, false);
    }

    return;

err_guest_notifiers:
    k->set_guest_notifiers(qbus->parent, rng->vhost_dev.nvqs, false);
err_host_notifiers:
    vhost_dev_disable_notifiers(&rng->vhost_dev, vdev);
}

static void vu_rng_stop(VirtIODevice *vdev)
{
    VHostUserRNG *rng = VHOST_USER_RNG(vdev);
    BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
    int ret;

    if (!k->set_guest_notifiers) {
        return;
    }

    vhost_dev_stop(&rng->vhost_dev, vdev);

    ret = k->set_guest_notifiers(qbus->parent, rng->vhost_dev.nvqs, false);
    if (ret < 0) {
        error_report("vhost guest notifier cleanup failed: %d", ret);
        return;
    }

    vhost_dev_disable_notifiers(&rng->vhost_dev, vdev);
}

static void vu_rng_set_status(VirtIODevice *vdev, uint8_t status)
{
    VHostUserRNG *rng = VHOST_USER_RNG(vdev);
    bool should_start = status & VIRTIO_CONFIG_S_DRIVER_OK;

    if (!vdev->vm_running) {
        should_start = false;
    }

    if (rng->vhost_dev.started == should_start) {
        return;
    }

    if (should_start) {
        vu_rng_start(vdev);
    } else {
        vu_rng_stop(vdev);
    }
}

static uint64_t vu_rng_get_features(VirtIODevice *vdev,
                                    uint64_t requested_features, Error **errp)
{
    /* No feature bits used yet */
    return requested_features;
}

static void vu_rng_handle_output(VirtIODevice *vdev, VirtQueue *vq)
{
    /*
     * Not normally called; it's the daemon that handles the queue;
     * however virtio's cleanup path can call this.
     */
}

static void vu_rng_guest_notifier_mask(VirtIODevice *vdev, int idx, bool mask)
{
    VHostUserRNG *rng = VHOST_USER_RNG(vdev);

    vhost_virtqueue_mask(&rng->vhost_dev, vdev, idx, mask);
}

static bool vu_rng_guest_notifier_pending(VirtIODevice *vdev, int idx)
{
    VHostUserRNG *rng = VHOST_USER_RNG(vdev);

    return vhost_virtqueue_pending(&rng->vhost_dev, idx);
}

static void vu_rng_connect(DeviceState *dev)
{
    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
    VHostUserRNG *rng = VHOST_USER_RNG(vdev);

    if (rng->connected) {
        return;
    }

    rng->connected = true;

    /* restore vhost state */
    if (virtio_device_started(vdev, vdev->status)) {
        vu_rng_start(vdev);
    }
}

static void vu_rng_disconnect(DeviceState *dev)
{
    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
    VHostUserRNG *rng = VHOST_USER_RNG(vdev);

    if (!rng->connected) {
        return;
    }

    rng->connected = false;

    if (rng->vhost_dev.started) {
        vu_rng_stop(vdev);
    }
}

static void vu_rng_event(void *opaque, QEMUChrEvent event)
{
    DeviceState *dev = opaque;

    switch (event) {
    case CHR_EVENT_OPENED:
        vu_rng_connect(dev);
        break;
    case CHR_EVENT_CLOSED:
        vu_rng_disconnect(dev);
        break;
    case CHR_EVENT_BREAK:
    case CHR_EVENT_MUX_IN:
    case CHR_EVENT_MUX_OUT:
        /* Ignore */
        break;
    }
}

static void vu_rng_device_realize(DeviceState *dev, Error **errp)
{
    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
    VHostUserRNG *rng = VHOST_USER_RNG(dev);
    int ret;

    if (!rng->chardev.chr) {
        error_setg(errp, "missing chardev");
        return;
    }

    if (!vhost_user_init(&rng->vhost_user, &rng->chardev, errp)) {
        return;
    }

    virtio_init(vdev, "vhost-user-rng", VIRTIO_ID_RNG, 0);

    rng->req_vq = virtio_add_queue(vdev, 4, vu_rng_handle_output);
    if (!rng->req_vq) {
        error_setg_errno(errp, -1, "virtio_add_queue() failed");
        goto virtio_add_queue_failed;
    }

    rng->vhost_dev.nvqs = 1;
    rng->vhost_dev.vqs = g_new0(struct vhost_virtqueue, rng->vhost_dev.nvqs);
    ret = vhost_dev_init(&rng->vhost_dev, &rng->vhost_user,
                         VHOST_BACKEND_TYPE_USER, 0, errp);
    if (ret < 0) {
        error_setg_errno(errp, -ret, "vhost_dev_init() failed");
        goto vhost_dev_init_failed;
    }

    qemu_chr_fe_set_handlers(&rng->chardev, NULL, NULL, vu_rng_event, NULL,
                             dev, NULL, true);

    return;

vhost_dev_init_failed:
    virtio_delete_queue(rng->req_vq);
virtio_add_queue_failed:
    virtio_cleanup(vdev);
    vhost_user_cleanup(&rng->vhost_user);
}

static void vu_rng_device_unrealize(DeviceState *dev)
{
    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
    VHostUserRNG *rng = VHOST_USER_RNG(dev);

    vu_rng_set_status(vdev, 0);

    vhost_dev_cleanup(&rng->vhost_dev);
    g_free(rng->vhost_dev.vqs);
    rng->vhost_dev.vqs = NULL;
    virtio_delete_queue(rng->req_vq);
    virtio_cleanup(vdev);
    vhost_user_cleanup(&rng->vhost_user);
}

static const VMStateDescription vu_rng_vmstate = {
    .name = "vhost-user-rng",
    .unmigratable = 1,
};

static Property vu_rng_properties[] = {
    DEFINE_PROP_CHR("chardev", VHostUserRNG, chardev),
    DEFINE_PROP_END_OF_LIST(),
};

static void vu_rng_class_init(ObjectClass *klass, void *data)
{
    DeviceClass *dc = DEVICE_CLASS(klass);
    VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);

    device_class_set_props(dc, vu_rng_properties);
    dc->vmsd = &vu_rng_vmstate;
    set_bit(DEVICE_CATEGORY_INPUT, dc->categories);

    vdc->realize = vu_rng_device_realize;
    vdc->unrealize = vu_rng_device_unrealize;
    vdc->get_features = vu_rng_get_features;
    vdc->set_status = vu_rng_set_status;
    vdc->guest_notifier_mask = vu_rng_guest_notifier_mask;
    vdc->guest_notifier_pending = vu_rng_guest_notifier_pending;
}

static const TypeInfo vu_rng_info = {
    .name = TYPE_VHOST_USER_RNG,
    .parent = TYPE_VIRTIO_DEVICE,
    .instance_size = sizeof(VHostUserRNG),
    .class_init = vu_rng_class_init,
};

static void vu_rng_register_types(void)
{
    type_register_static(&vu_rng_info);
}

type_init(vu_rng_register_types)