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
|
/*
* A virtio device implementing a hardware random number generator.
*
* Copyright 2012 Red Hat, Inc.
* Copyright 2012 Amit Shah <amit.shah@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or
* (at your option) any later version. See the COPYING file in the
* top-level directory.
*/
#include "iov.h"
#include "qdev.h"
#include "virtio.h"
#include "virtio-rng.h"
#include "qemu/rng.h"
typedef struct VirtIORNG {
VirtIODevice vdev;
DeviceState *qdev;
/* Only one vq - guest puts buffer(s) on it when it needs entropy */
VirtQueue *vq;
/* Config data for the device -- currently only chardev */
VirtIORNGConf *conf;
RngBackend *rng;
/* We purposefully don't migrate this state. The quota will reset on the
* destination as a result. Rate limiting is host state, not guest state.
*/
QEMUTimer *rate_limit_timer;
int64_t quota_remaining;
} VirtIORNG;
static bool is_guest_ready(VirtIORNG *vrng)
{
if (virtio_queue_ready(vrng->vq)
&& (vrng->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK)) {
return true;
}
return false;
}
static size_t get_request_size(VirtQueue *vq)
{
unsigned int in, out;
virtqueue_get_avail_bytes(vq, &in, &out);
return in;
}
static void virtio_rng_process(VirtIORNG *vrng);
/* Send data from a char device over to the guest */
static void chr_read(void *opaque, const void *buf, size_t size)
{
VirtIORNG *vrng = opaque;
VirtQueueElement elem;
size_t len;
int offset;
if (!is_guest_ready(vrng)) {
return;
}
vrng->quota_remaining -= size;
offset = 0;
while (offset < size) {
if (!virtqueue_pop(vrng->vq, &elem)) {
break;
}
len = iov_from_buf(elem.in_sg, elem.in_num,
0, buf + offset, size - offset);
offset += len;
virtqueue_push(vrng->vq, &elem, len);
}
virtio_notify(&vrng->vdev, vrng->vq);
}
static void virtio_rng_process(VirtIORNG *vrng)
{
size_t size;
if (!is_guest_ready(vrng)) {
return;
}
size = get_request_size(vrng->vq);
size = MIN(vrng->quota_remaining, size);
if (size) {
rng_backend_request_entropy(vrng->rng, size, chr_read, vrng);
}
}
static void handle_input(VirtIODevice *vdev, VirtQueue *vq)
{
VirtIORNG *vrng = DO_UPCAST(VirtIORNG, vdev, vdev);
virtio_rng_process(vrng);
}
static uint32_t get_features(VirtIODevice *vdev, uint32_t f)
{
return f;
}
static void virtio_rng_save(QEMUFile *f, void *opaque)
{
VirtIORNG *vrng = opaque;
virtio_save(&vrng->vdev, f);
}
static int virtio_rng_load(QEMUFile *f, void *opaque, int version_id)
{
VirtIORNG *vrng = opaque;
if (version_id != 1) {
return -EINVAL;
}
virtio_load(&vrng->vdev, f);
/* We may have an element ready but couldn't process it due to a quota
limit. Make sure to try again after live migration when the quota may
have been reset.
*/
virtio_rng_process(vrng);
return 0;
}
static void check_rate_limit(void *opaque)
{
VirtIORNG *s = opaque;
s->quota_remaining = s->conf->max_bytes;
virtio_rng_process(s);
qemu_mod_timer(s->rate_limit_timer,
qemu_get_clock_ms(vm_clock) + s->conf->period_ms);
}
VirtIODevice *virtio_rng_init(DeviceState *dev, VirtIORNGConf *conf)
{
VirtIORNG *vrng;
VirtIODevice *vdev;
Error *local_err = NULL;
vdev = virtio_common_init("virtio-rng", VIRTIO_ID_RNG, 0,
sizeof(VirtIORNG));
vrng = DO_UPCAST(VirtIORNG, vdev, vdev);
vrng->rng = conf->rng;
if (vrng->rng == NULL) {
qerror_report(QERR_INVALID_PARAMETER_VALUE, "rng", "a valid object");
return NULL;
}
rng_backend_open(vrng->rng, &local_err);
if (local_err) {
qerror_report_err(local_err);
error_free(local_err);
return NULL;
}
vrng->vq = virtio_add_queue(vdev, 8, handle_input);
vrng->vdev.get_features = get_features;
vrng->qdev = dev;
vrng->conf = conf;
vrng->quota_remaining = vrng->conf->max_bytes;
g_assert_cmpint(vrng->conf->max_bytes, <=, INT64_MAX);
vrng->rate_limit_timer = qemu_new_timer_ms(vm_clock,
check_rate_limit, vrng);
qemu_mod_timer(vrng->rate_limit_timer,
qemu_get_clock_ms(vm_clock) + vrng->conf->period_ms);
register_savevm(dev, "virtio-rng", -1, 1, virtio_rng_save,
virtio_rng_load, vrng);
return vdev;
}
void virtio_rng_exit(VirtIODevice *vdev)
{
VirtIORNG *vrng = DO_UPCAST(VirtIORNG, vdev, vdev);
qemu_del_timer(vrng->rate_limit_timer);
qemu_free_timer(vrng->rate_limit_timer);
unregister_savevm(vrng->qdev, "virtio-rng", vrng);
virtio_cleanup(vdev);
}
|
