Re: [PATCH v2 3/6] vhost-net: vhost-user: update vhost_net_virtqueue_reset()

[Xuan Zhuo <xuanzhuo@linux.alibaba.com>]

On Thu, 15 Sep 2022 10:12:11 +0800, Jason Wang <jasowang@redhat.com> wrote:
> On Wed, Sep 14, 2022 at 2:21 PM Xuan Zhuo <xuanzhuo@linux.alibaba.com> wrote:
> >
> > On Wed, 14 Sep 2022 11:13:29 +0800, Jason Wang <jasowang@redhat.com> wrote:
> > >
> > > 在 2022/9/12 11:10, Kangjie Xu 写道:
> > > > Update vhost_net_virtqueue_reset() for vhost-user scenario.
> > > >
> > > > In order to reuse some functions, we process the idx for
> > > > vhost-user scenario because vhost_get_vq_index behave
> > > > differently for vhost-user.
> > > >
> > > > Signed-off-by: Kangjie Xu <kangjie.xu@linux.alibaba.com>
> > > > Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> > > > ---
> > > >   hw/net/vhost_net.c | 3 +++
> > > >   1 file changed, 3 insertions(+)
> > > >
> > > > diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
> > > > index ea896ea75b..25e5665489 100644
> > > > --- a/hw/net/vhost_net.c
> > > > +++ b/hw/net/vhost_net.c
> > > > @@ -545,6 +545,9 @@ void vhost_net_virtqueue_reset(VirtIODevice *vdev, NetClientState *nc,
> > > >       assert(vhost_ops);
> > > >
> > > >       idx = vhost_ops->vhost_get_vq_index(&net->dev, vq_index);
> > > > +    if (net->nc->info->type == NET_CLIENT_DRIVER_VHOST_USER) {
> > > > +        idx -= net->dev.vq_index;
> > > > +    }
> > >
> > >
> > > This looks tricky. Any reason we can't simply use vq_index for both
> > > vhost-user and vhost-net?
> >
> >
> > static int vhost_user_get_vq_index(struct vhost_dev *dev, int idx)
> > {
> >     assert(idx >= dev->vq_index && idx < dev->vq_index + dev->nvqs);
> >
> >     return idx;
> > }
> >
> >
> > static int vhost_kernel_get_vq_index(struct vhost_dev *dev, int idx)
> > {
> >     assert(idx >= dev->vq_index && idx < dev->vq_index + dev->nvqs);
> >
> >     return idx - dev->vq_index;
> > }
> >
> > The implementation of these two callbacks is different. The structure of the two
> > scenarios is different. We may need to do some optimizations in the future.
>
> Yes, but what I meant is, you do
>
> idx -= net->dev.vq_index;
>
> and then
>
> net->dev.vq_index + idx
>
> This is a hint that we should have a better organization of the code.

I see.

Will fix this.

Thanks.


>
> Thanks
>
> >
> > Thanks.
> >
> >
> > >
> > > Thanks
> > >
> > >
> > > >
> > > >       if (net->nc->info->type == NET_CLIENT_DRIVER_TAP) {
> > > >           file.index = idx;
> > >
> >
>