usr/src/cmd/bhyve/pci_virtio_rnd.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   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/cdefs.h>
  37 __FBSDID("$FreeBSD$");
  38
  39 #include <sys/param.h>
  40 #ifndef WITHOUT_CAPSICUM
  41 #include <sys/capsicum.h>
  42 #endif
  43 #include <sys/linker_set.h>
  44 #include <sys/uio.h>
  45
  46 #ifndef WITHOUT_CAPSICUM
  47 #include <capsicum_helpers.h>
  48 #endif
  49 #include <err.h>
  50 #include <errno.h>
  51 #include <fcntl.h>
  52 #include <stdio.h>
  53 #include <stdlib.h>
  54 #include <string.h>
  55 #include <unistd.h>
  56 #include <assert.h>
  57 #include <pthread.h>
  58 #include <sysexits.h>
  59
  60 #include "bhyverun.h"
  61 #include "debug.h"
  62 #include "pci_emul.h"
  63 #include "virtio.h"
  64
  65 #define VTRND_RINGSZ    64
  66
  67
  68 static int pci_vtrnd_debug;
  69 #define DPRINTF(params) if (pci_vtrnd_debug) PRINTLN params
  70 #define WPRINTF(params) PRINTLN params
  71
  72 /*
  73  * Per-device softc
  74  */
  75 struct pci_vtrnd_softc {
  76         struct virtio_softc vrsc_vs;
  77         struct vqueue_info  vrsc_vq;
  78         pthread_mutex_t     vrsc_mtx;
  79         uint64_t            vrsc_cfg;
  80         int                 vrsc_fd;
  81 };
  82
  83 static void pci_vtrnd_reset(void *);
  84 static void pci_vtrnd_notify(void *, struct vqueue_info *);
  85
  86 static struct virtio_consts vtrnd_vi_consts = {
  87         .vc_name =      "vtrnd",
  88         .vc_nvq =       1,
  89         .vc_cfgsize =   0,
  90         .vc_reset =     pci_vtrnd_reset,
  91         .vc_qnotify =   pci_vtrnd_notify,
  92         .vc_hv_caps =   0,
  93 };
  94
  95 static void
  96 pci_vtrnd_reset(void *vsc)
  97 {
  98         struct pci_vtrnd_softc *sc;
  99
 100         sc = vsc;
 101
 102         DPRINTF(("vtrnd: device reset requested !"));
 103         vi_reset_dev(&sc->vrsc_vs);
 104 }
 105
 106
 107 static void
 108 pci_vtrnd_notify(void *vsc, struct vqueue_info *vq)
 109 {
 110         struct iovec iov;
 111         struct pci_vtrnd_softc *sc;
 112         struct vi_req req;
 113         int len, n;
 114
 115         sc = vsc;
 116
 117         if (sc->vrsc_fd < 0) {
 118                 vq_endchains(vq, 0);
 119                 return;
 120         }
 121
 122         while (vq_has_descs(vq)) {
 123                 n = vq_getchain(vq, &iov, 1, &req);
 124                 assert(n == 1);
 125
 126                 len = read(sc->vrsc_fd, iov.iov_base, iov.iov_len);
 127
 128                 DPRINTF(("vtrnd: vtrnd_notify(): %d", len));
 129
 130                 /* Catastrophe if unable to read from /dev/random */
 131                 assert(len > 0);
 132
 133                 /*
 134                  * Release this chain and handle more
 135                  */
 136                 vq_relchain(vq, req.idx, len);
 137         }
 138         vq_endchains(vq, 1);    /* Generate interrupt if appropriate. */
 139 }
 140
 141
 142 static int
 143 pci_vtrnd_init(struct vmctx *ctx __unused, struct pci_devinst *pi,
 144     nvlist_t *nvl __unused)
 145 {
 146         struct pci_vtrnd_softc *sc;
 147         int fd;
 148         int len;
 149         uint8_t v;
 150 #ifndef WITHOUT_CAPSICUM
 151         cap_rights_t rights;
 152 #endif
 153
 154         /*
 155          * Should always be able to open /dev/random.
 156          */
 157         fd = open("/dev/random", O_RDONLY | O_NONBLOCK);
 158
 159         assert(fd >= 0);
 160
 161 #ifndef WITHOUT_CAPSICUM
 162         cap_rights_init(&rights, CAP_READ);
 163         if (caph_rights_limit(fd, &rights) == -1)
 164                 errx(EX_OSERR, "Unable to apply rights for sandbox");
 165 #endif
 166
 167         /*
 168          * Check that device is seeded and non-blocking.
 169          */
 170         len = read(fd, &v, sizeof(v));
 171         if (len <= 0) {
 172                 WPRINTF(("vtrnd: /dev/random not ready, read(): %d", len));
 173                 close(fd);
 174                 return (1);
 175         }
 176
 177         sc = calloc(1, sizeof(struct pci_vtrnd_softc));
 178
 179         pthread_mutex_init(&sc->vrsc_mtx, NULL);
 180
 181         vi_softc_linkup(&sc->vrsc_vs, &vtrnd_vi_consts, sc, pi, &sc->vrsc_vq);
 182         sc->vrsc_vs.vs_mtx = &sc->vrsc_mtx;
 183
 184         sc->vrsc_vq.vq_qsize = VTRND_RINGSZ;
 185
 186         /* keep /dev/random opened while emulating */
 187         sc->vrsc_fd = fd;
 188
 189         /* initialize config space */
 190         pci_set_cfgdata16(pi, PCIR_DEVICE, VIRTIO_DEV_RANDOM);
 191         pci_set_cfgdata16(pi, PCIR_VENDOR, VIRTIO_VENDOR);
 192         pci_set_cfgdata8(pi, PCIR_CLASS, PCIC_CRYPTO);
 193         pci_set_cfgdata16(pi, PCIR_SUBDEV_0, VIRTIO_ID_ENTROPY);
 194         pci_set_cfgdata16(pi, PCIR_SUBVEND_0, VIRTIO_VENDOR);
 195
 196         if (vi_intr_init(&sc->vrsc_vs, 1, fbsdrun_virtio_msix()))
 197                 return (1);
 198         vi_set_io_bar(&sc->vrsc_vs, 0);
 199
 200         return (0);
 201 }
 202
 203
 204 static const struct pci_devemu pci_de_vrnd = {
 205         .pe_emu =       "virtio-rnd",
 206         .pe_init =      pci_vtrnd_init,
 207         .pe_barwrite =  vi_pci_write,
 208         .pe_barread =   vi_pci_read,
 209 };
 210 PCI_EMUL_SET(pci_de_vrnd);