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sys/dev/virtio/random/virtio_random.c
| Show First 20 Lines • Show All 223 Lines • ▼ Show 20 Lines | |||||
| } | } | ||||
| static int | static int | ||||
| vtrnd_harvest(struct vtrnd_softc *sc, void *buf, size_t *sz) | vtrnd_harvest(struct vtrnd_softc *sc, void *buf, size_t *sz) | ||||
| { | { | ||||
| struct sglist_seg segs[1]; | struct sglist_seg segs[1]; | ||||
| struct sglist sg; | struct sglist sg; | ||||
| struct virtqueue *vq; | struct virtqueue *vq; | ||||
| void *cookie; | |||||
| uint32_t value[HARVESTSIZE] __aligned(sizeof(uint32_t) * HARVESTSIZE); | uint32_t value[HARVESTSIZE] __aligned(sizeof(uint32_t) * HARVESTSIZE); | ||||
| uint32_t rdlen; | uint32_t rdlen; | ||||
| int error; | int error; | ||||
| _Static_assert(sizeof(value) < PAGE_SIZE, "sglist assumption"); | _Static_assert(sizeof(value) < PAGE_SIZE, "sglist assumption"); | ||||
| sglist_init(&sg, 1, segs); | sglist_init(&sg, 1, segs); | ||||
| error = sglist_append(&sg, value, *sz); | error = sglist_append(&sg, value, *sz); | ||||
| if (error != 0) | if (error != 0) | ||||
| panic("%s: sglist_append error=%d", __func__, error); | panic("%s: sglist_append error=%d", __func__, error); | ||||
| vq = sc->vtrnd_vq; | vq = sc->vtrnd_vq; | ||||
| KASSERT(virtqueue_empty(vq), ("%s: non-empty queue", __func__)); | KASSERT(virtqueue_empty(vq), ("%s: non-empty queue", __func__)); | ||||
| error = virtqueue_enqueue(vq, buf, &sg, 0, 1); | error = virtqueue_enqueue(vq, buf, &sg, 0, 1); | ||||
| if (error != 0) | if (error != 0) | ||||
| return (error); | return (error); | ||||
| /* | /* | ||||
| * Poll for the response, but the command is likely already | * Poll for the response, but the command is likely already | ||||
| * done when we return from the notify. | * done when we return from the notify. | ||||
| */ | */ | ||||
| virtqueue_notify(vq); | virtqueue_notify(vq); | ||||
| virtqueue_poll(vq, &rdlen); | cookie = virtqueue_poll(vq, &rdlen); | ||||
| /* Almost trivially true, but could indicate something bad. */ | |||||
| KASSERT(cookie == buf, ("inconsistent virtqueue state")); | |||||
| if (rdlen > *sz) | if (rdlen > *sz) | ||||
| panic("%s: random device wrote %zu bytes beyond end of provided" | panic("%s: random device wrote %zu bytes beyond end of provided" | ||||
| " buffer %p:%zu", __func__, (size_t)rdlen - *sz, | " buffer %p:%zu", __func__, (size_t)rdlen - *sz, | ||||
| (void *)value, *sz); | (void *)value, *sz); | ||||
| else if (rdlen == 0) | else if (rdlen == 0) | ||||
| return (EAGAIN); | return (EAGAIN); | ||||
| *sz = MIN(rdlen, *sz); | *sz = MIN(rdlen, *sz); | ||||
| Show All 23 Lines | |||||