pci_virtio_rnd.c revision 268933 
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: stable/10/usr.sbin/bhyve/pci_virtio_rnd.c 268933 2014-07-21 00:21:56Z jhb $");
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
57static 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 */
64struct 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
72static void pci_vtrnd_reset(void *);
73static void pci_vtrnd_notify(void *, struct vqueue_info *);
74
75static 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	0,			/* our capabilities */
84};
85
86
87static void
88pci_vtrnd_reset(void *vsc)
89{
90	struct pci_vtrnd_softc *sc;
91
92	sc = vsc;
93
94	DPRINTF(("vtrnd: device reset requested !\n"));
95	vi_reset_dev(&sc->vrsc_vs);
96}
97
98
99static void
100pci_vtrnd_notify(void *vsc, struct vqueue_info *vq)
101{
102	struct iovec iov;
103	struct pci_vtrnd_softc *sc;
104	int len;
105
106	sc = vsc;
107
108	vq_startchains(vq);
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, &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, len);
129	}
130	vq_endchains(vq, 1);	/* Generate interrupt if appropriate. */
131}
132
133
134static int
135pci_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 = malloc(sizeof(struct pci_vtrnd_softc));
159	memset(sc, 0, sizeof(struct pci_vtrnd_softc));
160
161	vi_softc_linkup(&sc->vrsc_vs, &vtrnd_vi_consts, sc, pi, &sc->vrsc_vq);
162	sc->vrsc_vs.vs_mtx = &sc->vrsc_mtx;
163
164	sc->vrsc_vq.vq_qsize = VTRND_RINGSZ;
165
166	/* keep /dev/random opened while emulating */
167	sc->vrsc_fd = fd;
168
169	/* initialize config space */
170	pci_set_cfgdata16(pi, PCIR_DEVICE, VIRTIO_DEV_RANDOM);
171	pci_set_cfgdata16(pi, PCIR_VENDOR, VIRTIO_VENDOR);
172	pci_set_cfgdata8(pi, PCIR_CLASS, PCIC_CRYPTO);
173	pci_set_cfgdata16(pi, PCIR_SUBDEV_0, VIRTIO_TYPE_ENTROPY);
174
175	if (vi_intr_init(&sc->vrsc_vs, 1, fbsdrun_virtio_msix()))
176		return (1);
177	vi_set_io_bar(&sc->vrsc_vs, 0);
178
179	return (0);
180}
181
182
183struct pci_devemu pci_de_vrnd = {
184	.pe_emu =	"virtio-rnd",
185	.pe_init =	pci_vtrnd_init,
186	.pe_barwrite =	vi_pci_write,
187	.pe_barread =	vi_pci_read
188};
189PCI_EMUL_SET(pci_de_vrnd);
190