Re: [virtio-dev] Re: [PATCH v9] virtio-net: support inner header hash

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Mar 02, 2023 at 04:15:39PM +0800, Jason Wang wrote:
> On Thu, Mar 2, 2023 at 4:10 PM Michael S. Tsirkin <mst@redhat.com> wrote:
> >
> > On Thu, Mar 02, 2023 at 03:57:10PM +0800, Jason Wang wrote:
> > > Kernel had already used the eBPF program for hashing, classifying
> > > various types of eBPF program other than XDP/socket filter
> > > (pass/drop).
> > >
> > > Thanks
> >
> > where is it used for hashing?
> 
> I can see it is used by team/lb:
> 
> static unsigned int lb_get_skb_hash(struct lb_priv *lb_priv,
>                                     struct sk_buff *skb)
> {
>         struct bpf_prog *fp;
>         uint32_t lhash;
>         unsigned char *c;
> 
>         fp = rcu_dereference_bh(lb_priv->fp);
>         if (unlikely(!fp))
>                 return 0;
>         lhash = bpf_prog_run(fp, skb);
>         c = (char *) &lhash;
>         return c[0] ^ c[1] ^ c[2] ^ c[3];
> }
> 
> But the point is that the return value is determined by the prog type
> (or the context).
> 
> Thanks

OK so assuming we do this, how will users program this exactly?
Given this is not standard, which tools will be used to attach such
a program to the device?


> >
> > --
> > MST
> >
> >
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> >


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