Messages in this thread | | | Subject | Re: [PATCH net 1/2] virtio-net: disable guest csum during XDP set | From | Jason Wang <> | Date | Mon, 26 Nov 2018 12:03:39 +0800 |
| |
On 2018/11/24 上午4:01, David Miller wrote: > From: Jason Wang <jasowang@redhat.com> > Date: Thu, 22 Nov 2018 14:36:30 +0800 > >> We don't disable VIRTIO_NET_F_GUEST_CSUM if XDP was set. This means we >> can receive partial csumed packets with metadata kept in the >> vnet_hdr. This may have several side effects: >> >> - It could be overridden by header adjustment, thus is might be not >> correct after XDP processing. >> - There's no way to pass such metadata information through >> XDP_REDIRECT to another driver. >> - XDP does not support checksum offload right now. >> >> So simply disable guest csum if possible in this the case of XDP. >> >> Fixes: 3f93522ffab2d ("virtio-net: switch off offloads on demand if possible on XDP set") >> Reported-by: Jesper Dangaard Brouer <brouer@redhat.com> >> Cc: Jesper Dangaard Brouer <brouer@redhat.com> >> Cc: Pavel Popa <pashinho1990@gmail.com> >> Cc: David Ahern <dsahern@gmail.com> >> Signed-off-by: Jason Wang <jasowang@redhat.com> > Applied and queued up for -stable. > > We really should have a way to use the checksum provided if the XDP > program returns XDP_PASS and does not modify the packet contents > or size.
Yes, I think this may require the assistance of BPF verifier to set a flag or other. Then we can assume the metadata is safe to use.
Thanks
| |