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diff --git a/sys/dev/virtio/random/virtio_random.c b/sys/dev/virtio/random/virtio_random.c
--- a/sys/dev/virtio/random/virtio_random.c
+++ b/sys/dev/virtio/random/virtio_random.c
@@ -54,6 +54,8 @@
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_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
@@ -138,12 +141,17 @@
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");
@@ -174,6 +182,8 @@
sc->inactive = false;
random_source_register(&random_vtrnd);
+ vtrnd_enqueue(sc);
+
fail:
if (error)
vtrnd_detach(dev);
@@ -185,6 +195,7 @@
vtrnd_detach(device_t dev)
{
struct vtrnd_softc *sc;
+ uint32_t rdlen;
sc = device_get_softc(dev);
KASSERT(
@@ -197,7 +208,13 @@
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);
}
@@ -251,49 +268,45 @@
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);
}

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