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 #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 "pci_emul.h" 59 #include "virtio.h" 60 61 #define VTRND_RINGSZ 64 62 63 64 static int pci_vtrnd_debug; 65 #define DPRINTF(params) if (pci_vtrnd_debug) printf params 66 #define WPRINTF(params) printf params 67 68 /* 69 * Per-device softc 70 */ 71 struct pci_vtrnd_softc { 72 struct virtio_softc vrsc_vs; 73 struct vqueue_info vrsc_vq; 74 pthread_mutex_t vrsc_mtx; 75 uint64_t vrsc_cfg; 76 int vrsc_fd; 77 }; 78 79 static void pci_vtrnd_reset(void *); 80 static void pci_vtrnd_notify(void *, struct vqueue_info *); 81 82 static struct virtio_consts vtrnd_vi_consts = { 83 "vtrnd", /* our name */ 84 1, /* we support 1 virtqueue */ 85 0, /* config reg size */ 86 pci_vtrnd_reset, /* reset */ 87 pci_vtrnd_notify, /* device-wide qnotify */ 88 NULL, /* read virtio config */ 89 NULL, /* write virtio config */ 90 NULL, /* apply negotiated features */ 91 0, /* our capabilities */ 92 }; 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 !\n")); 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 int len; 113 uint16_t idx; 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 vq_getchain(vq, &idx, &iov, 1, NULL); 124 125 len = read(sc->vrsc_fd, iov.iov_base, iov.iov_len); 126 127 DPRINTF(("vtrnd: vtrnd_notify(): %d\r\n", len)); 128 129 /* Catastrophe if unable to read from /dev/random */ 130 assert(len > 0); 131 132 /* 133 * Release this chain and handle more 134 */ 135 vq_relchain(vq, idx, len); 136 } 137 vq_endchains(vq, 1); /* Generate interrupt if appropriate. */ 138 } 139 140 141 static int 142 pci_vtrnd_init(struct vmctx *ctx, struct pci_devinst *pi, char *opts) 143 { 144 struct pci_vtrnd_softc *sc; 145 int fd; 146 int len; 147 uint8_t v; 148 #ifndef WITHOUT_CAPSICUM 149 cap_rights_t rights; 150 #endif 151 152 /* 153 * Should always be able to open /dev/random. 154 */ 155 fd = open("/dev/random", O_RDONLY | O_NONBLOCK); 156 157 assert(fd >= 0); 158 159 #ifndef WITHOUT_CAPSICUM 160 cap_rights_init(&rights, CAP_READ); 161 if (cap_rights_limit(fd, &rights) == -1 && errno != ENOSYS) 162 errx(EX_OSERR, "Unable to apply rights for sandbox"); 163 #endif 164 165 /* 166 * Check that device is seeded and non-blocking. 167 */ 168 len = read(fd, &v, sizeof(v)); 169 if (len <= 0) { 170 WPRINTF(("vtrnd: /dev/random not ready, read(): %d", len)); 171 close(fd); 172 return (1); 173 } 174 175 sc = calloc(1, sizeof(struct pci_vtrnd_softc)); 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_TYPE_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 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 }; 206 PCI_EMUL_SET(pci_de_vrnd); 207