Re: [PATCH v2 5/8] tools/virtio: Use __vring_new_virtqueue in virtio_test.c

[Eugenio Perez Martin]

On Fri, Apr 17, 2020 at 12:33 AM Michael S. Tsirkin <mst@xxxxxxxxxx> wrote:
>
> On Thu, Apr 16, 2020 at 09:56:40AM +0200, Eugenio PÃrez wrote:
> > As updated in ("2a2d1382fe9d virtio: Add improved queue allocation API")
> >
> > Signed-off-by: Eugenio PÃrez <eperezma@xxxxxxxxxx>
>
> Pls add motivation for these changes.
>

The original motivation was to make code as close as possible to
virtio_net. Also, it skips a (probably not expensive) initialization
in vring_new_virtqueue.

With the recent events, I think that this could be useful to test when
userspace and kernel use different struct layout, maybe with some
sanitizer. I can drop it if you don't see it the same way (or if I
didn't understand the problem and this does not help).

Thanks!

> > ---
> >  tools/virtio/virtio_test.c | 7 +++----
> >  1 file changed, 3 insertions(+), 4 deletions(-)
> >
> > diff --git a/tools/virtio/virtio_test.c b/tools/virtio/virtio_test.c
> > index 1d5144590df6..d9827b640c21 100644
> > --- a/tools/virtio/virtio_test.c
> > +++ b/tools/virtio/virtio_test.c
> > @@ -106,10 +106,9 @@ static void vq_info_add(struct vdev_info *dev, int num)
> >       assert(r >= 0);
> >       memset(info->ring, 0, vring_legacy_size(num, 4096));
> >       vring_legacy_init(&info->vring, num, info->ring, 4096);
> > -     info->vq = vring_new_virtqueue(info->idx,
> > -                                    info->vring.num, 4096, &dev->vdev,
> > -                                    true, false, info->ring,
> > -                                    vq_notify, vq_callback, "test");
> > +     info->vq =
> > +             __vring_new_virtqueue(info->idx, info->vring, &dev->vdev, true,
> > +                                   false, vq_notify, vq_callback, "test");
> >       assert(info->vq);
> >       info->vq->priv = info;
> >       vhost_vq_setup(dev, info);
> > --
> > 2.18.1
>