diff options
| -rw-r--r-- | sys/dev/virtio/random/virtio_random.c | 73 |
1 files changed, 43 insertions, 30 deletions
diff --git a/sys/dev/virtio/random/virtio_random.c b/sys/dev/virtio/random/virtio_random.c index 1088a218c957..d2e34714cb26 100644 --- a/sys/dev/virtio/random/virtio_random.c +++ b/sys/dev/virtio/random/virtio_random.c @@ -54,6 +54,8 @@ struct vtrnd_softc { 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 *); @@ -67,6 +69,7 @@ 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 @@ -140,12 +143,17 @@ 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"); @@ -176,6 +184,8 @@ vtrnd_attach(device_t dev) sc->inactive = false; random_source_register(&random_vtrnd); + vtrnd_enqueue(sc); + fail: if (error) vtrnd_detach(dev); @@ -187,6 +197,7 @@ static int vtrnd_detach(device_t dev) { struct vtrnd_softc *sc; + uint32_t rdlen; sc = device_get_softc(dev); KASSERT( @@ -199,7 +210,13 @@ vtrnd_detach(device_t dev) 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); } @@ -253,49 +270,45 @@ vtrnd_alloc_virtqueue(struct vtrnd_softc *sc) 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); } |