On Thu, Sep 25, 2025 at 12:39 PM +02, Lorenzo Bianconi wrote:
On Thu, Sep 25, 2025 at 11:30 AM +02, Lorenzo Bianconi wrote:
Introduce bpf_xdp_metadata_rx_checksum() kfunc in order to load the HW RX cheksum results in the eBPF program binded to the NIC. Implement xmo_rx_checksum callback for veth and ice drivers.
What are going to do with HW RX checksum once XDP prog can access it?
I guess there are multiple use-cases for bpf_xdp_metadata_rx_checksum() kfunc. The first the I have in mind is when packets are received by an af_xdp application. In this case I think we currently do not have any way to check if the packet checksum is correct, right? I think Jesper has other use-cases in mind, I will let him comment here.
Can you share more details on what the AF_XDP application would that info?
Regarding the use cases that Jesper is trying to unlock, as things stand we don't have a way, or an agreement on how to inject/propagate even the already existing NIC hints back into the network stack.
Hence my question - why do we want to expose another NIC hint to XDP that we can't consume in any useful way yet?
Shouldn't we first figure out how we're planning to re-inject that info into the stack?