1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2014 Nahanni Systems Inc.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer
12 * in this position and unchanged.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30 /*
31 * virtio entropy device emulation.
32 * Randomness is sourced from /dev/random which does not block
33 * once it has been seeded at bootup.
34 */
35
36 #include <sys/param.h>
37 #ifndef WITHOUT_CAPSICUM
38 #include <sys/capsicum.h>
39 #endif
40 #include <sys/linker_set.h>
41 #include <sys/uio.h>
42
43 #ifndef WITHOUT_CAPSICUM
44 #include <capsicum_helpers.h>
45 #endif
46 #include <err.h>
47 #include <errno.h>
48 #include <fcntl.h>
49 #include <stdio.h>
50 #include <stdlib.h>
51 #include <string.h>
52 #include <unistd.h>
53 #include <assert.h>
54 #include <pthread.h>
55 #include <sysexits.h>
56
57 #include "bhyverun.h"
58 #include "debug.h"
59 #include "pci_emul.h"
60 #include "virtio.h"
61
62 #define VTRND_RINGSZ 64
63
64
65 static int pci_vtrnd_debug;
66 #define DPRINTF(params) if (pci_vtrnd_debug) PRINTLN params
67 #define WPRINTF(params) PRINTLN params
68
69 /*
70 * Per-device softc
71 */
72 struct pci_vtrnd_softc {
73 struct virtio_softc vrsc_vs;
74 struct vqueue_info vrsc_vq;
75 pthread_mutex_t vrsc_mtx;
76 uint64_t vrsc_cfg;
77 int vrsc_fd;
78 };
79
80 static void pci_vtrnd_reset(void *);
81 static void pci_vtrnd_notify(void *, struct vqueue_info *);
82
83 static struct virtio_consts vtrnd_vi_consts = {
84 .vc_name = "vtrnd",
85 .vc_nvq = 1,
86 .vc_cfgsize = 0,
87 .vc_reset = pci_vtrnd_reset,
88 .vc_qnotify = pci_vtrnd_notify,
89 .vc_hv_caps = 0,
90 };
91
92 static void
pci_vtrnd_reset(void * vsc)93 pci_vtrnd_reset(void *vsc)
94 {
95 struct pci_vtrnd_softc *sc;
96
97 sc = vsc;
98
99 DPRINTF(("vtrnd: device reset requested !"));
100 vi_reset_dev(&sc->vrsc_vs);
101 }
102
103
104 static void
pci_vtrnd_notify(void * vsc,struct vqueue_info * vq)105 pci_vtrnd_notify(void *vsc, struct vqueue_info *vq)
106 {
107 struct iovec iov;
108 struct pci_vtrnd_softc *sc;
109 struct vi_req req;
110 int len, n;
111
112 sc = vsc;
113
114 if (sc->vrsc_fd < 0) {
115 vq_endchains(vq, 0);
116 return;
117 }
118
119 while (vq_has_descs(vq)) {
120 n = vq_getchain(vq, &iov, 1, &req);
121 assert(n == 1);
122
123 len = read(sc->vrsc_fd, iov.iov_base, iov.iov_len);
124
125 DPRINTF(("vtrnd: vtrnd_notify(): %d", len));
126
127 /* Catastrophe if unable to read from /dev/random */
128 assert(len > 0);
129
130 /*
131 * Release this chain and handle more
132 */
133 vq_relchain(vq, req.idx, len);
134 }
135 vq_endchains(vq, 1); /* Generate interrupt if appropriate. */
136 }
137
138
139 static int
pci_vtrnd_init(struct pci_devinst * pi,nvlist_t * nvl __unused)140 pci_vtrnd_init(struct pci_devinst *pi, nvlist_t *nvl __unused)
141 {
142 struct pci_vtrnd_softc *sc;
143 int fd;
144 int len;
145 uint8_t v;
146 #ifndef WITHOUT_CAPSICUM
147 cap_rights_t rights;
148 #endif
149
150 /*
151 * Should always be able to open /dev/random.
152 */
153 fd = open("/dev/random", O_RDONLY | O_NONBLOCK);
154
155 assert(fd >= 0);
156
157 #ifndef WITHOUT_CAPSICUM
158 cap_rights_init(&rights, CAP_READ);
159 if (caph_rights_limit(fd, &rights) == -1)
160 errx(EX_OSERR, "Unable to apply rights for sandbox");
161 #endif
162
163 /*
164 * Check that device is seeded and non-blocking.
165 */
166 len = read(fd, &v, sizeof(v));
167 if (len <= 0) {
168 WPRINTF(("vtrnd: /dev/random not ready, read(): %d", len));
169 close(fd);
170 return (1);
171 }
172
173 sc = calloc(1, sizeof(struct pci_vtrnd_softc));
174
175 pthread_mutex_init(&sc->vrsc_mtx, NULL);
176
177 vi_softc_linkup(&sc->vrsc_vs, &vtrnd_vi_consts, sc, pi, &sc->vrsc_vq);
178 sc->vrsc_vs.vs_mtx = &sc->vrsc_mtx;
179
180 sc->vrsc_vq.vq_qsize = VTRND_RINGSZ;
181
182 /* keep /dev/random opened while emulating */
183 sc->vrsc_fd = fd;
184
185 /* initialize config space */
186 pci_set_cfgdata16(pi, PCIR_DEVICE, VIRTIO_DEV_RANDOM);
187 pci_set_cfgdata16(pi, PCIR_VENDOR, VIRTIO_VENDOR);
188 pci_set_cfgdata8(pi, PCIR_CLASS, PCIC_CRYPTO);
189 pci_set_cfgdata16(pi, PCIR_SUBDEV_0, VIRTIO_ID_ENTROPY);
190 pci_set_cfgdata16(pi, PCIR_SUBVEND_0, VIRTIO_VENDOR);
191
192 if (vi_intr_init(&sc->vrsc_vs, 1, fbsdrun_virtio_msix()))
193 return (1);
194 vi_set_io_bar(&sc->vrsc_vs, 0);
195
196 return (0);
197 }
198
199
200 static const struct pci_devemu pci_de_vrnd = {
201 .pe_emu = "virtio-rnd",
202 .pe_init = pci_vtrnd_init,
203 .pe_barwrite = vi_pci_write,
204 .pe_barread = vi_pci_read,
205 #ifdef BHYVE_SNAPSHOT
206 .pe_snapshot = vi_pci_snapshot,
207 #endif
208 };
209 PCI_EMUL_SET(pci_de_vrnd);
210