Received-SPF: pass (google.com: domain of linux-kernel+bounces-38047-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45d1:ec00::1 as permitted sender) client-ip=2604:1380:45d1:ec00::1;
Message-ID: <1706164863.507014-6-xuanzhuo@linux.alibaba.com>
Subject: Re: [PATCH v2 2/3] virtio_net: Add missing virtio header in skb for XDP_PASS
Date: Thu, 25 Jan 2024 14:41:03 +0800
From: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
To: Jason Wang <jasowang@redhat.com>
Cc: Liang Chen <liangchen.linux@gmail.com>,
 virtualization@lists.linux-foundation.org,
 linux-kernel@vger.kernel.org,
 mst@redhat.com,
 hengqi@linux.alibaba.com
References: <20240124085721.54442-1-liangchen.linux@gmail.com>
 <20240124085721.54442-3-liangchen.linux@gmail.com>
 <1706087654.2583706-2-xuanzhuo@linux.alibaba.com>
 <CACGkMEvQTXmyAeUeWxgxgMPJ3VQJWH1DRnt__Yb0ifnSyuZ7Cw@mail.gmail.com>
In-Reply-To: <CACGkMEvQTXmyAeUeWxgxgMPJ3VQJWH1DRnt__Yb0ifnSyuZ7Cw@mail.gmail.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Thu, 25 Jan 2024 11:48:18 +0800, Jason Wang <jasowang@redhat.com> wrote:
> On Wed, Jan 24, 2024 at 5:16=E2=80=AFPM Xuan Zhuo <xuanzhuo@linux.alibaba=
com> wrote:
> >
> > On Wed, 24 Jan 2024 16:57:20 +0800, Liang Chen <liangchen.linux@gmail.c=
om> wrote:
> > > For the XDP_PASS scenario of the XDP path, the skb constructed with
> > > xdp_buff does not include the virtio header. Adding the virtio header
> > > information back when creating the skb.
> > >
> > > Signed-off-by: Liang Chen <liangchen.linux@gmail.com>
> > > ---
> > >  drivers/net/virtio_net.c | 6 ++++++
> > >  1 file changed, 6 insertions(+)
> > >
> > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> > > index b56828804e5f..2de46eb4c661 100644
> > > --- a/drivers/net/virtio_net.c
> > > +++ b/drivers/net/virtio_net.c
> > > @@ -1270,6 +1270,9 @@ static struct sk_buff *receive_small_xdp(struct=
 net_device *dev,
> > >       if (unlikely(!skb))
> > >               goto err;
> > >
> > > +     /* Store the original virtio header for subsequent use by the d=
river. */
> > > +     memcpy(skb_vnet_common_hdr(skb), &virtnet_xdp.hdr, vi->hdr_len);
> >
> > About this, a spec is waiting for voting.
> >
>
> A pointer?

Sorry.

http://lore.kernel.org/all/1704263702-50528-1-git-send-email-hengqi@linux.a=
libaba.com


>
> > This may change the logic of the csum offset and so on.
>
>  Btw, doesn't it need a new feature bit?

Yes.

But this patch set should not include this.
We may do the similar thing, but the commit log will
include more info about the spec.

Thanks.


>
> Thanks
>
> >
> > Please not do this.
> >
> > Thanks.
> >
> >
> > > +
> > >       if (metasize)
> > >               skb_metadata_set(skb, metasize);
> > >
> > > @@ -1635,6 +1638,9 @@ static struct sk_buff *receive_mergeable_xdp(st=
ruct net_device *dev,
> > >               head_skb =3D build_skb_from_xdp_buff(dev, vi, xdp, xdp_=
frags_truesz);
> > >               if (unlikely(!head_skb))
> > >                       break;
> > > +             /* Store the original virtio header for subsequent use =
by the driver. */
> > > +             memcpy(skb_vnet_common_hdr(head_skb), &virtnet_xdp.hdr,=
 vi->hdr_len);
> > > +
> > >               return head_skb;
> > >
> > >       case XDP_TX:
> > > --
> > > 2.40.1
> > >
> >
>