diff --git a/sys/dev/virtio/random/virtio_random.c b/sys/dev/virtio/random/virtio_random.c index c02b5c98cece..d54e2e6b70d4 100644 --- a/sys/dev/virtio/random/virtio_random.c +++ b/sys/dev/virtio/random/virtio_random.c @@ -1,317 +1,330 @@ /*- * SPDX-License-Identifier: BSD-2-Clause * * Copyright (c) 2013, Bryan Venteicher * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice unmodified, this list of conditions, and the following * disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /* Driver for VirtIO entropy device. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include struct vtrnd_softc { device_t vtrnd_dev; uint64_t vtrnd_features; struct virtqueue *vtrnd_vq; eventhandler_tag eh; bool inactive; + struct sglist *vtrnd_sg; + uint32_t *vtrnd_value; }; static int vtrnd_modevent(module_t, int, void *); static int vtrnd_probe(device_t); static int vtrnd_attach(device_t); static int vtrnd_detach(device_t); static int vtrnd_shutdown(device_t); static int vtrnd_negotiate_features(struct vtrnd_softc *); static int vtrnd_setup_features(struct vtrnd_softc *); static int vtrnd_alloc_virtqueue(struct vtrnd_softc *); static int vtrnd_harvest(struct vtrnd_softc *, void *, size_t *); +static void vtrnd_enqueue(struct vtrnd_softc *sc); static unsigned vtrnd_read(void *, unsigned); #define VTRND_FEATURES 0 static struct virtio_feature_desc vtrnd_feature_desc[] = { { 0, NULL } }; static struct random_source random_vtrnd = { .rs_ident = "VirtIO Entropy Adapter", .rs_source = RANDOM_PURE_VIRTIO, .rs_read = vtrnd_read, }; /* Kludge for API limitations of random(4). */ static _Atomic(struct vtrnd_softc *) g_vtrnd_softc; static device_method_t vtrnd_methods[] = { /* Device methods. */ DEVMETHOD(device_probe, vtrnd_probe), DEVMETHOD(device_attach, vtrnd_attach), DEVMETHOD(device_detach, vtrnd_detach), DEVMETHOD(device_shutdown, vtrnd_shutdown), DEVMETHOD_END }; static driver_t vtrnd_driver = { "vtrnd", vtrnd_methods, sizeof(struct vtrnd_softc) }; VIRTIO_DRIVER_MODULE(virtio_random, vtrnd_driver, vtrnd_modevent, NULL); MODULE_VERSION(virtio_random, 1); MODULE_DEPEND(virtio_random, virtio, 1, 1, 1); MODULE_DEPEND(virtio_random, random_device, 1, 1, 1); VIRTIO_SIMPLE_PNPINFO(virtio_random, VIRTIO_ID_ENTROPY, "VirtIO Entropy Adapter"); static int vtrnd_modevent(module_t mod, int type, void *unused) { int error; switch (type) { case MOD_LOAD: case MOD_QUIESCE: case MOD_UNLOAD: case MOD_SHUTDOWN: error = 0; break; default: error = EOPNOTSUPP; break; } return (error); } static int vtrnd_probe(device_t dev) { return (VIRTIO_SIMPLE_PROBE(dev, virtio_random)); } static int vtrnd_attach(device_t dev) { struct vtrnd_softc *sc, *exp; + size_t len; int error; sc = device_get_softc(dev); sc->vtrnd_dev = dev; virtio_set_feature_desc(dev, vtrnd_feature_desc); + len = sizeof(*sc->vtrnd_value) * HARVESTSIZE; + sc->vtrnd_value = malloc_aligned(len, len, M_DEVBUF, M_WAITOK); + sc->vtrnd_sg = sglist_build(sc->vtrnd_value, len, M_WAITOK); + error = vtrnd_setup_features(sc); if (error) { device_printf(dev, "cannot setup features\n"); goto fail; } error = vtrnd_alloc_virtqueue(sc); if (error) { device_printf(dev, "cannot allocate virtqueue\n"); goto fail; } exp = NULL; if (!atomic_compare_exchange_strong_explicit(&g_vtrnd_softc, &exp, sc, memory_order_release, memory_order_acquire)) { error = EEXIST; goto fail; } sc->eh = EVENTHANDLER_REGISTER(shutdown_post_sync, vtrnd_shutdown, dev, SHUTDOWN_PRI_LAST + 1); /* ??? */ if (sc->eh == NULL) { device_printf(dev, "Shutdown event registration failed\n"); error = ENXIO; goto fail; } sc->inactive = false; random_source_register(&random_vtrnd); + vtrnd_enqueue(sc); + fail: if (error) vtrnd_detach(dev); return (error); } static int vtrnd_detach(device_t dev) { struct vtrnd_softc *sc; + uint32_t rdlen; sc = device_get_softc(dev); KASSERT( atomic_load_explicit(&g_vtrnd_softc, memory_order_acquire) == sc, ("only one global instance at a time")); sc->inactive = true; if (sc->eh != NULL) { EVENTHANDLER_DEREGISTER(shutdown_post_sync, sc->eh); sc->eh = NULL; } random_source_deregister(&random_vtrnd); + + /* clear the queue */ + virtqueue_poll(sc->vtrnd_vq, &rdlen); + atomic_store_explicit(&g_vtrnd_softc, NULL, memory_order_release); + sglist_free(sc->vtrnd_sg); + zfree(sc->vtrnd_value, M_DEVBUF); return (0); } static int vtrnd_shutdown(device_t dev) { struct vtrnd_softc *sc; sc = device_get_softc(dev); sc->inactive = true; return(0); } static int vtrnd_negotiate_features(struct vtrnd_softc *sc) { device_t dev; uint64_t features; dev = sc->vtrnd_dev; features = VTRND_FEATURES; sc->vtrnd_features = virtio_negotiate_features(dev, features); return (virtio_finalize_features(dev)); } static int vtrnd_setup_features(struct vtrnd_softc *sc) { int error; error = vtrnd_negotiate_features(sc); if (error) return (error); return (0); } static int vtrnd_alloc_virtqueue(struct vtrnd_softc *sc) { device_t dev; struct vq_alloc_info vq_info; dev = sc->vtrnd_dev; VQ_ALLOC_INFO_INIT(&vq_info, 0, NULL, sc, &sc->vtrnd_vq, "%s request", device_get_nameunit(dev)); return (virtio_alloc_virtqueues(dev, 0, 1, &vq_info)); } +static void +vtrnd_enqueue(struct vtrnd_softc *sc) +{ + struct virtqueue *vq; + int error __diagused; + + vq = sc->vtrnd_vq; + + KASSERT(virtqueue_empty(vq), ("%s: non-empty queue", __func__)); + + error = virtqueue_enqueue(vq, sc, sc->vtrnd_sg, 0, 1); + KASSERT(error == 0, ("%s: virtqueue_enqueue returned error: %d", + __func__, error)); + + virtqueue_notify(vq); +} + static int vtrnd_harvest(struct vtrnd_softc *sc, void *buf, size_t *sz) { - struct sglist_seg segs[1]; - struct sglist sg; struct virtqueue *vq; - uint32_t value[HARVESTSIZE] __aligned(sizeof(uint32_t) * HARVESTSIZE); + void *cookie; uint32_t rdlen; - int error; - - _Static_assert(sizeof(value) < PAGE_SIZE, "sglist assumption"); if (sc->inactive) return (EDEADLK); - sglist_init(&sg, 1, segs); - error = sglist_append(&sg, value, *sz); - if (error != 0) - panic("%s: sglist_append error=%d", __func__, error); - vq = sc->vtrnd_vq; - KASSERT(virtqueue_empty(vq), ("%s: non-empty queue", __func__)); - - error = virtqueue_enqueue(vq, buf, &sg, 0, 1); - if (error != 0) - return (error); - - /* - * Poll for the response, but the command is likely already - * done when we return from the notify. - */ - virtqueue_notify(vq); - virtqueue_poll(vq, &rdlen); - if (rdlen > *sz) - panic("%s: random device wrote %zu bytes beyond end of provided" - " buffer %p:%zu", __func__, (size_t)rdlen - *sz, - (void *)value, *sz); - else if (rdlen == 0) + cookie = virtqueue_dequeue(vq, &rdlen); + if (cookie == NULL) return (EAGAIN); + KASSERT(cookie == sc, ("%s: cookie mismatch", __func__)); + *sz = MIN(rdlen, *sz); - memcpy(buf, value, *sz); - explicit_bzero(value, *sz); + memcpy(buf, sc->vtrnd_value, *sz); + + vtrnd_enqueue(sc); + return (0); } static unsigned vtrnd_read(void *buf, unsigned usz) { struct vtrnd_softc *sc; size_t sz; int error; sc = g_vtrnd_softc; if (sc == NULL) return (0); sz = usz; error = vtrnd_harvest(sc, buf, &sz); if (error != 0) return (0); return (sz); }