On Wed, Apr 01, 2020 at 08:31:18PM +0200, Eugenio Pérez wrote:
> Signed-off-by: Eugenio Pérez <[email protected]>
I'm still a bit puzzled by this one - could you
explain what the rationale here is?
> ---
> drivers/virtio/virtio_ring.c | 29 +++++++++++++++++++++++++++++
> tools/virtio/linux/virtio.h | 2 ++
> tools/virtio/virtio_test.c | 28 +++++++++++++++++++++++++++-
> 3 files changed, 58 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> index 58b96baa8d48..f9153a381f72 100644
> --- a/drivers/virtio/virtio_ring.c
> +++ b/drivers/virtio/virtio_ring.c
> @@ -1810,6 +1810,35 @@ int virtqueue_add_inbuf_ctx(struct virtqueue *vq,
> }
> EXPORT_SYMBOL_GPL(virtqueue_add_inbuf_ctx);
>
> +#ifndef __KERNEL__
> +
> +/**
> + * virtqueue_reset_free_head - Reset to 0 the members of split ring.
> + * @vq: Virtqueue to reset.
> + *
> + * At this moment, is only meant for debug the ring index change, do not use
> + * in production.
> + */
> +void virtqueue_reset_free_head(struct virtqueue *_vq)
> +{
> + struct vring_virtqueue *vq = to_vvq(_vq);
> +
> + // vq->last_used_idx = 0;
> + vq->num_added = 0;
> +
> + vq->split.queue_size_in_bytes = 0;
> + vq->split.avail_flags_shadow = 0;
> + vq->split.avail_idx_shadow = 0;
> +
> + memset(vq->split.desc_state, 0, vq->split.vring.num *
> + sizeof(struct vring_desc_state_split));
> +
> + vq->free_head = 0;
> +}
> +EXPORT_SYMBOL_GPL(virtqueue_reset_free_head);
> +
> +#endif
> +
> /**
> * virtqueue_kick_prepare - first half of split virtqueue_kick call.
> * @_vq: the struct virtqueue
> diff --git a/tools/virtio/linux/virtio.h b/tools/virtio/linux/virtio.h
> index b751350d4ce8..5d33eab6b814 100644
> --- a/tools/virtio/linux/virtio.h
> +++ b/tools/virtio/linux/virtio.h
> @@ -65,4 +65,6 @@ struct virtqueue *vring_new_virtqueue(unsigned int index,
> const char *name);
> void vring_del_virtqueue(struct virtqueue *vq);
>
> +void virtqueue_reset_free_head(struct virtqueue *vq);
> +
> #endif
> diff --git a/tools/virtio/virtio_test.c b/tools/virtio/virtio_test.c
> index 93d81cd64ba0..bf21ece30594 100644
> --- a/tools/virtio/virtio_test.c
> +++ b/tools/virtio/virtio_test.c
> @@ -49,6 +49,7 @@ struct vdev_info {
>
> static const struct vhost_vring_file no_backend = { .fd = -1 },
> backend = { .fd = 1 };
> +static const struct vhost_vring_state null_state = {};
>
> bool vq_notify(struct virtqueue *vq)
> {
> @@ -218,10 +219,33 @@ static void run_test(struct vdev_info *dev, struct
> vq_info *vq,
> }
>
> if (reset) {
> + struct vhost_vring_state s = { .index = 0 };
> + int i;
> + vq->vring.avail->idx = 0;
> + vq->vq->num_free = vq->vring.num;
> +
> + // Put everything in free lists.
> + for (i = 0; i < vq->vring.num-1; i++)
> + vq->vring.desc[i].next =
> + cpu_to_virtio16(&dev->vdev,
> + i + 1);
> + vq->vring.desc[vq->vring.num-1].next = 0;
Poking at vq descriptors like this seems fragile.
I think this calls for a better API that handles everything
internally.
> + virtqueue_reset_free_head(vq->vq);
> +
> + r = ioctl(dev->control, VHOST_GET_VRING_BASE,
> + &s);
> + assert(!r);
> +
> + s.num = 0;
> + r = ioctl(dev->control, VHOST_SET_VRING_BASE,
> + &null_state);
> + assert(!r);
> +
> r = ioctl(dev->control, VHOST_TEST_SET_BACKEND,
> &backend);
> assert(!r);
>
> + started = completed;
> while (completed > next_reset)
> next_reset += completed;
> }
> @@ -243,7 +267,9 @@ static void run_test(struct vdev_info *dev, struct
> vq_info *vq,
> test = 0;
> r = ioctl(dev->control, VHOST_TEST_RUN, &test);
> assert(r >= 0);
> - fprintf(stderr, "spurious wakeups: 0x%llx\n", spurious);
> + fprintf(stderr,
> + "spurious wakeups: 0x%llx started=0x%lx completed=0x%lx\n",
> + spurious, started, completed);
> }
>
> const char optstring[] = "h";
> --
> 2.18.1
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