On 11/05, Mina Almasry wrote: > For device memory TCP, we expect the skb headers to be available in host > memory for access, and we expect the skb frags to be in device memory > and unaccessible to the host. We expect there to be no mixing and > matching of device memory frags (unaccessible) with host memory frags > (accessible) in the same skb. > > Add a skb->devmem flag which indicates whether the frags in this skb > are device memory frags or not. > > __skb_fill_page_desc() now checks frags added to skbs for page_pool_iovs, > and marks the skb as skb->devmem accordingly. > > Add checks through the network stack to avoid accessing the frags of > devmem skbs and avoid coalescing devmem skbs with non devmem skbs. > > Signed-off-by: Willem de Bruijn <will...@google.com> > Signed-off-by: Kaiyuan Zhang <kaiyu...@google.com> > Signed-off-by: Mina Almasry <almasrym...@google.com>
[..] > - snaplen = skb->len; > + snaplen = skb_frags_not_readable(skb) ? skb_headlen(skb) : skb->len; > > res = run_filter(skb, sk, snaplen); > if (!res) > @@ -2279,7 +2279,7 @@ static int tpacket_rcv(struct sk_buff *skb, struct > net_device *dev, > } > } > > - snaplen = skb->len; > + snaplen = skb_frags_not_readable(skb) ? skb_headlen(skb) : skb->len; > > res = run_filter(skb, sk, snaplen); > if (!res) Not sure it covers 100% of bpf. We might need to double-check bpf_xdp_copy_buf which is having its own, non-skb shinfo and frags. And in general, xdp can reference those shinfo frags early... (xdp part happens before we create an skb with all devmem association)
