viornd.c revision 1.19
1 /* $NetBSD: viornd.c,v 1.19 2023/03/23 03:27:48 yamaguchi Exp $ */ 2 /* $OpenBSD: viornd.c,v 1.1 2014/01/21 21:14:58 sf Exp $ */ 3 4 /* 5 * Copyright (c) 2014 The NetBSD Foundation, Inc. 6 * All rights reserved. 7 * 8 * This code is derived from software contributed to The NetBSD Foundation 9 * by Thor Lancelot Simon (tls (at) NetBSD.org). 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 23 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 30 * POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 /* 34 * Copyright (c) 2014 Stefan Fritsch <sf (at) sfritsch.de> 35 * 36 * Permission to use, copy, modify, and distribute this software for any 37 * purpose with or without fee is hereby granted, provided that the above 38 * copyright notice and this permission notice appear in all copies. 39 * 40 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 41 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 42 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 43 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 44 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 45 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 46 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 47 */ 48 49 #include <sys/param.h> 50 #include <sys/systm.h> 51 #include <sys/kernel.h> 52 #include <sys/device.h> 53 #include <sys/callout.h> 54 #include <sys/rndsource.h> 55 #include <sys/mutex.h> 56 #include <dev/pci/virtioreg.h> 57 #include <dev/pci/virtiovar.h> 58 59 #define VIORND_BUFSIZE 32 60 61 #define VIORND_DEBUG 0 62 63 struct viornd_softc { 64 device_t sc_dev; 65 struct virtio_softc *sc_virtio; 66 67 kmutex_t sc_mutex; 68 bool sc_active; 69 70 void *sc_buf; 71 struct virtqueue sc_vq; 72 bus_dmamap_t sc_dmamap; 73 krndsource_t sc_rndsource; 74 }; 75 76 int viornd_match(device_t, cfdata_t, void *); 77 void viornd_attach(device_t, device_t, void *); 78 int viornd_vq_done(struct virtqueue *); 79 80 CFATTACH_DECL_NEW(viornd, sizeof(struct viornd_softc), 81 viornd_match, viornd_attach, NULL, NULL); 82 83 static void 84 viornd_get(size_t bytes, void *priv) 85 { 86 struct viornd_softc *sc = priv; 87 struct virtio_softc *vsc = sc->sc_virtio; 88 struct virtqueue *vq = &sc->sc_vq; 89 int slot; 90 91 #if VIORND_DEBUG 92 aprint_normal("%s: asked for %d bytes of entropy\n", __func__, 93 VIORND_BUFSIZE); 94 #endif 95 mutex_enter(&sc->sc_mutex); 96 97 if (sc->sc_active) { 98 goto out; 99 } 100 101 bus_dmamap_sync(virtio_dmat(vsc), sc->sc_dmamap, 0, VIORND_BUFSIZE, 102 BUS_DMASYNC_PREREAD); 103 if (virtio_enqueue_prep(vsc, vq, &slot)) { 104 goto out; 105 } 106 if (virtio_enqueue_reserve(vsc, vq, slot, 1)) { 107 goto out; 108 } 109 virtio_enqueue(vsc, vq, slot, sc->sc_dmamap, 0); 110 virtio_enqueue_commit(vsc, vq, slot, 1); 111 sc->sc_active = true; 112 out: 113 mutex_exit(&sc->sc_mutex); 114 } 115 116 int 117 viornd_match(device_t parent, cfdata_t match, void *aux) 118 { 119 struct virtio_attach_args *va = aux; 120 121 if (va->sc_childdevid == VIRTIO_DEVICE_ID_ENTROPY) 122 return 1; 123 124 return 0; 125 } 126 127 void 128 viornd_attach(device_t parent, device_t self, void *aux) 129 { 130 struct viornd_softc *sc = device_private(self); 131 struct virtio_softc *vsc = device_private(parent); 132 bus_dma_segment_t segs[1]; 133 int nsegs; 134 int error; 135 136 if (virtio_child(vsc) != NULL) 137 panic("already attached to something else"); 138 139 sc->sc_dev = self; 140 sc->sc_virtio = vsc; 141 142 mutex_init(&sc->sc_mutex, MUTEX_DEFAULT, IPL_VM); 143 144 error = bus_dmamem_alloc(virtio_dmat(vsc), 145 VIRTIO_PAGE_SIZE, 0, 0, segs, 1, &nsegs, 146 BUS_DMA_NOWAIT|BUS_DMA_ALLOCNOW); 147 if (error) { 148 aprint_error_dev(sc->sc_dev, "can't alloc dmamem: %d\n", 149 error); 150 goto alloc_failed; 151 } 152 153 error = bus_dmamem_map(virtio_dmat(vsc), segs, nsegs, VIORND_BUFSIZE, 154 &sc->sc_buf, BUS_DMA_NOWAIT); 155 if (error) { 156 aprint_error_dev(sc->sc_dev, "can't map dmamem: %d\n", error); 157 goto map_failed; 158 } 159 160 error = bus_dmamap_create(virtio_dmat(vsc), VIORND_BUFSIZE, 1, 161 VIORND_BUFSIZE, 0, 162 BUS_DMA_NOWAIT|BUS_DMA_ALLOCNOW, 163 &sc->sc_dmamap); 164 if (error) { 165 aprint_error_dev(sc->sc_dev, "can't alloc dmamap: %d\n", 166 error); 167 goto create_failed; 168 } 169 170 error = bus_dmamap_load(virtio_dmat(vsc), sc->sc_dmamap, 171 sc->sc_buf, VIORND_BUFSIZE, NULL, 172 BUS_DMA_NOWAIT|BUS_DMA_READ); 173 if (error) { 174 aprint_error_dev(sc->sc_dev, "can't load dmamap: %d\n", 175 error); 176 goto load_failed; 177 } 178 179 virtio_child_attach_start(vsc, self, IPL_NET, 180 0, VIRTIO_COMMON_FLAG_BITS); 181 182 error = virtio_alloc_vq(vsc, &sc->sc_vq, 0, VIORND_BUFSIZE, 1, 183 "Entropy request"); 184 if (error) { 185 aprint_error_dev(sc->sc_dev, "can't alloc virtqueue: %d\n", 186 error); 187 goto vio_failed; 188 } 189 sc->sc_vq.vq_done = viornd_vq_done; 190 191 error = virtio_child_attach_finish(vsc, &sc->sc_vq, 1, 192 NULL, virtio_vq_intr, 0); 193 if (error) { 194 virtio_free_vq(vsc, &sc->sc_vq); 195 goto vio_failed; 196 } 197 198 rndsource_setcb(&sc->sc_rndsource, viornd_get, sc); 199 rnd_attach_source(&sc->sc_rndsource, device_xname(sc->sc_dev), 200 RND_TYPE_RNG, 201 RND_FLAG_COLLECT_VALUE|RND_FLAG_HASCB); 202 203 return; 204 205 vio_failed: 206 bus_dmamap_unload(virtio_dmat(vsc), sc->sc_dmamap); 207 load_failed: 208 bus_dmamap_destroy(virtio_dmat(vsc), sc->sc_dmamap); 209 create_failed: 210 bus_dmamem_unmap(virtio_dmat(vsc), sc->sc_buf, VIORND_BUFSIZE); 211 map_failed: 212 bus_dmamem_free(virtio_dmat(vsc), segs, nsegs); 213 alloc_failed: 214 virtio_child_attach_failed(vsc); 215 return; 216 } 217 218 int 219 viornd_vq_done(struct virtqueue *vq) 220 { 221 struct virtio_softc *vsc = vq->vq_owner; 222 struct viornd_softc *sc = device_private(virtio_child(vsc)); 223 int slot, len; 224 225 mutex_enter(&sc->sc_mutex); 226 227 if (virtio_dequeue(vsc, vq, &slot, &len) != 0) { 228 mutex_exit(&sc->sc_mutex); 229 return 0; 230 } 231 232 sc->sc_active = false; 233 234 bus_dmamap_sync(virtio_dmat(vsc), sc->sc_dmamap, 0, VIORND_BUFSIZE, 235 BUS_DMASYNC_POSTREAD); 236 if (len > VIORND_BUFSIZE) { 237 aprint_error_dev(sc->sc_dev, 238 "inconsistent descriptor length %d > %d\n", 239 len, VIORND_BUFSIZE); 240 goto out; 241 } 242 243 #if VIORND_DEBUG 244 aprint_normal("%s: got %d bytes of entropy\n", __func__, len); 245 #endif 246 rnd_add_data(&sc->sc_rndsource, sc->sc_buf, VIORND_BUFSIZE, 247 VIORND_BUFSIZE * NBBY); 248 out: 249 virtio_dequeue_commit(vsc, vq, slot); 250 mutex_exit(&sc->sc_mutex); 251 252 return 1; 253 } 254
Indexes created Tue Sep 30 20:09:53 GMT 2025