On Sun, 15 Sep 2024 10:17:39 +0900 Akihiko Odaki <akihiko.odaki@xxxxxxxxxx> wrote: > virtio-net have two usage of hashes: one is RSS and another is hash > reporting. Conventionally the hash calculation was done by the VMM. > However, computing the hash after the queue was chosen defeats the > purpose of RSS. > > Another approach is to use eBPF steering program. This approach has > another downside: it cannot report the calculated hash due to the > restrictive nature of eBPF. > > Introduce the code to compute hashes to the kernel in order to overcome > thse challenges. > > An alternative solution is to extend the eBPF steering program so that it > will be able to report to the userspace, but it is based on context > rewrites, which is in feature freeze. We can adopt kfuncs, but they will > not be UAPIs. We opt to ioctl to align with other relevant UAPIs (KVM > and vhost_net). This will be useful for DPDK. But there still are cases where custom flow rules are needed. I.e the RSS happens after other TC rules. It would be a good if skbedit supported RSS as an option.
