1 /*-
2 * Copyright (c) 2014 Nahanni Systems Inc.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer
10 * in this position and unchanged.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28 /*
29 * virtio entropy device emulation.
30 * Randomness is sourced from /dev/random which does not block
31 * once it has been seeded at bootup.
32 */
33
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
36
37 #include <sys/param.h>
38 #include <sys/linker_set.h>
39 #include <sys/uio.h>
40
41 #include <errno.h>
42 #include <fcntl.h>
43 #include <stdio.h>
44 #include <stdlib.h>
45 #include <string.h>
46 #include <unistd.h>
47 #include <assert.h>
48 #include <pthread.h>
49
50 #include "bhyverun.h"
51 #include "pci_emul.h"
52 #include "virtio.h"
53
54 #define VTRND_RINGSZ 64
55
56
57 static int pci_vtrnd_debug;
58 #define DPRINTF(params) if (pci_vtrnd_debug) printf params
59 #define WPRINTF(params) printf params
60
61 /*
62 * Per-device softc
63 */
64 struct pci_vtrnd_softc {
65 struct virtio_softc vrsc_vs;
66 struct vqueue_info vrsc_vq;
67 pthread_mutex_t vrsc_mtx;
68 uint64_t vrsc_cfg;
69 int vrsc_fd;
70 };
71
72 static void pci_vtrnd_reset(void *);
73 static void pci_vtrnd_notify(void *, struct vqueue_info *);
74
75 static struct virtio_consts vtrnd_vi_consts = {
76 "vtrnd", /* our name */
77 1, /* we support 1 virtqueue */
78 0, /* config reg size */
79 pci_vtrnd_reset, /* reset */
80 pci_vtrnd_notify, /* device-wide qnotify */
81 NULL, /* read virtio config */
82 NULL, /* write virtio config */
83 NULL, /* apply negotiated features */
84 0, /* our capabilities */
85 };
86
87
88 static void
pci_vtrnd_reset(void * vsc)89 pci_vtrnd_reset(void *vsc)
90 {
91 struct pci_vtrnd_softc *sc;
92
93 sc = vsc;
94
95 DPRINTF(("vtrnd: device reset requested !\n"));
96 vi_reset_dev(&sc->vrsc_vs);
97 }
98
99
100 static void
pci_vtrnd_notify(void * vsc,struct vqueue_info * vq)101 pci_vtrnd_notify(void *vsc, struct vqueue_info *vq)
102 {
103 struct iovec iov;
104 struct pci_vtrnd_softc *sc;
105 int len;
106 uint16_t idx;
107
108 sc = vsc;
109
110 if (sc->vrsc_fd < 0) {
111 vq_endchains(vq, 0);
112 return;
113 }
114
115 while (vq_has_descs(vq)) {
116 vq_getchain(vq, &idx, &iov, 1, NULL);
117
118 len = read(sc->vrsc_fd, iov.iov_base, iov.iov_len);
119
120 DPRINTF(("vtrnd: vtrnd_notify(): %d\r\n", len));
121
122 /* Catastrophe if unable to read from /dev/random */
123 assert(len > 0);
124
125 /*
126 * Release this chain and handle more
127 */
128 vq_relchain(vq, idx, len);
129 }
130 vq_endchains(vq, 1); /* Generate interrupt if appropriate. */
131 }
132
133
134 static int
pci_vtrnd_init(struct vmctx * ctx,struct pci_devinst * pi,char * opts)135 pci_vtrnd_init(struct vmctx *ctx, struct pci_devinst *pi, char *opts)
136 {
137 struct pci_vtrnd_softc *sc;
138 int fd;
139 int len;
140 uint8_t v;
141
142 /*
143 * Should always be able to open /dev/random.
144 */
145 fd = open("/dev/random", O_RDONLY | O_NONBLOCK);
146
147 assert(fd >= 0);
148
149 /*
150 * Check that device is seeded and non-blocking.
151 */
152 len = read(fd, &v, sizeof(v));
153 if (len <= 0) {
154 WPRINTF(("vtrnd: /dev/random not ready, read(): %d", len));
155 return (1);
156 }
157
158 sc = calloc(1, sizeof(struct pci_vtrnd_softc));
159
160 vi_softc_linkup(&sc->vrsc_vs, &vtrnd_vi_consts, sc, pi, &sc->vrsc_vq);
161 sc->vrsc_vs.vs_mtx = &sc->vrsc_mtx;
162
163 sc->vrsc_vq.vq_qsize = VTRND_RINGSZ;
164
165 /* keep /dev/random opened while emulating */
166 sc->vrsc_fd = fd;
167
168 /* initialize config space */
169 pci_set_cfgdata16(pi, PCIR_DEVICE, VIRTIO_DEV_RANDOM);
170 pci_set_cfgdata16(pi, PCIR_VENDOR, VIRTIO_VENDOR);
171 pci_set_cfgdata8(pi, PCIR_CLASS, PCIC_CRYPTO);
172 pci_set_cfgdata16(pi, PCIR_SUBDEV_0, VIRTIO_TYPE_ENTROPY);
173
174 if (vi_intr_init(&sc->vrsc_vs, 1, fbsdrun_virtio_msix()))
175 return (1);
176 vi_set_io_bar(&sc->vrsc_vs, 0);
177
178 return (0);
179 }
180
181
182 struct pci_devemu pci_de_vrnd = {
183 .pe_emu = "virtio-rnd",
184 .pe_init = pci_vtrnd_init,
185 .pe_barwrite = vi_pci_write,
186 .pe_barread = vi_pci_read
187 };
188 PCI_EMUL_SET(pci_de_vrnd);
189