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 #ifndef WITHOUT_CAPSICUM 39 #include <sys/capsicum.h> 40 #endif 41 #include <sys/linker_set.h> 42 #include <sys/uio.h> 43 44 #include <err.h> 45 #include <errno.h> 46 #include <fcntl.h> 47 #include <stdio.h> 48 #include <stdlib.h> 49 #include <string.h> 50 #include <unistd.h> 51 #include <assert.h> 52 #include <pthread.h> 53 #include <sysexits.h> 54 55 #include "bhyverun.h" 56 #include "pci_emul.h" 57 #include "virtio.h" 58 59 #define VTRND_RINGSZ 64 60 61 62 static int pci_vtrnd_debug; 63 #define DPRINTF(params) if (pci_vtrnd_debug) printf params 64 #define WPRINTF(params) printf params 65 66 /* 67 * Per-device softc 68 */ 69 struct pci_vtrnd_softc { 70 struct virtio_softc vrsc_vs; 71 struct vqueue_info vrsc_vq; 72 pthread_mutex_t vrsc_mtx; 73 uint64_t vrsc_cfg; 74 int vrsc_fd; 75 }; 76 77 static void pci_vtrnd_reset(void *); 78 static void pci_vtrnd_notify(void *, struct vqueue_info *); 79 80 static struct virtio_consts vtrnd_vi_consts = { 81 "vtrnd", /* our name */ 82 1, /* we support 1 virtqueue */ 83 0, /* config reg size */ 84 pci_vtrnd_reset, /* reset */ 85 pci_vtrnd_notify, /* device-wide qnotify */ 86 NULL, /* read virtio config */ 87 NULL, /* write virtio config */ 88 NULL, /* apply negotiated features */ 89 0, /* our capabilities */ 90 }; 91 92 93 static void 94 pci_vtrnd_reset(void *vsc) 95 { 96 struct pci_vtrnd_softc *sc; 97 98 sc = vsc; 99 100 DPRINTF(("vtrnd: device reset requested !\n")); 101 vi_reset_dev(&sc->vrsc_vs); 102 } 103 104 105 static void 106 pci_vtrnd_notify(void *vsc, struct vqueue_info *vq) 107 { 108 struct iovec iov; 109 struct pci_vtrnd_softc *sc; 110 int len; 111 uint16_t idx; 112 113 sc = vsc; 114 115 if (sc->vrsc_fd < 0) { 116 vq_endchains(vq, 0); 117 return; 118 } 119 120 while (vq_has_descs(vq)) { 121 vq_getchain(vq, &idx, &iov, 1, NULL); 122 123 len = read(sc->vrsc_fd, iov.iov_base, iov.iov_len); 124 125 DPRINTF(("vtrnd: vtrnd_notify(): %d\r\n", 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, idx, len); 134 } 135 vq_endchains(vq, 1); /* Generate interrupt if appropriate. */ 136 } 137 138 139 static int 140 pci_vtrnd_init(struct vmctx *ctx, struct pci_devinst *pi, char *opts) 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 (cap_rights_limit(fd, &rights) == -1 && errno != ENOSYS) 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 return (1); 170 } 171 172 sc = calloc(1, sizeof(struct pci_vtrnd_softc)); 173 174 vi_softc_linkup(&sc->vrsc_vs, &vtrnd_vi_consts, sc, pi, &sc->vrsc_vq); 175 sc->vrsc_vs.vs_mtx = &sc->vrsc_mtx; 176 177 sc->vrsc_vq.vq_qsize = VTRND_RINGSZ; 178 179 /* keep /dev/random opened while emulating */ 180 sc->vrsc_fd = fd; 181 182 /* initialize config space */ 183 pci_set_cfgdata16(pi, PCIR_DEVICE, VIRTIO_DEV_RANDOM); 184 pci_set_cfgdata16(pi, PCIR_VENDOR, VIRTIO_VENDOR); 185 pci_set_cfgdata8(pi, PCIR_CLASS, PCIC_CRYPTO); 186 pci_set_cfgdata16(pi, PCIR_SUBDEV_0, VIRTIO_TYPE_ENTROPY); 187 pci_set_cfgdata16(pi, PCIR_SUBVEND_0, VIRTIO_VENDOR); 188 189 if (vi_intr_init(&sc->vrsc_vs, 1, fbsdrun_virtio_msix())) 190 return (1); 191 vi_set_io_bar(&sc->vrsc_vs, 0); 192 193 return (0); 194 } 195 196 197 struct pci_devemu pci_de_vrnd = { 198 .pe_emu = "virtio-rnd", 199 .pe_init = pci_vtrnd_init, 200 .pe_barwrite = vi_pci_write, 201 .pe_barread = vi_pci_read 202 }; 203 PCI_EMUL_SET(pci_de_vrnd); 204