On Tue, Apr 2, 2024 at 5:43 PM Toke Høiland-Jørgensen <toke@xxxxxxxxxx> wrote: > > Jamal Hadi Salim <jhs@xxxxxxxxxxxx> writes: > > > This is the first patchset of two. In this patch we are submitting 15 which > > cover the minimal viable P4 PNA architecture. > > Please, if you want to discuss a slightly tangential subject like offload or > > even your politics then start another thread with a different subject line. > > The way you do it is to change the subject line to for example > > "<Your New Subject here> (WAS: <original subject line here>)". > > > > In this cover letter i am restoring text i took out in V10 which stated "our > > requirements". > > > > Martin, please look at patch 14 again. The bpf selftests for kfuncs is > > sloted for series 2. Paolo, please take a look at 1, 3, 6 for the changes > > you suggested. Marcelo, because we made changes to patch 14, I have > > removed your reviewed-by. Can you please take another look at that patch? > > > > __Description of these Patches__ > > > > These Patches are constrained entirely within the TC domain with very tiny > > changes made in patch 1-5. eBPF is used as an infrastructure component for > > the software datapath and no changes are made to any eBPF code, only kfuncs > > are introduced in patch 14. > > > > Patch #1 adds infrastructure for per-netns P4 actions that can be created on > > as need basis for the P4 program requirement. This patch makes a small > > incision into act_api. Patches 2-4 are minimalist enablers for P4TC and have > > no effect on the classical tc action (example patch#2 just increases the size > > of the action names from 16->64B). > > Patch 5 adds infrastructure support for preallocation of dynamic actions > > needed for P4. > > > > The core P4TC code implements several P4 objects. > > 1) Patch #6 introduces P4 data types which are consumed by the rest of the > > code > > 2) Patch #7 introduces the templating API. i.e. CRUD commands for templates > > 3) Patch #8 introduces the concept of templating Pipelines. i.e CRUD > > commands for P4 pipelines. > > 4) Patch #9 introduces the action templates and associated CRUD commands. > > 5) Patch #10 introduce the action runtime infrastructure. > > 6) Patch #11 introduces the concept of P4 table templates and associated > > CRUD commands for tables. > > 7) Patch #12 introduces runtime table entry infra and associated CU > > commands. > > 8) Patch #13 introduces runtime table entry infra and associated RD > > commands. > > 9) Patch #14 introduces interaction of eBPF to P4TC tables via kfunc. > > 10) Patch #15 introduces the TC classifier P4 used at runtime. > > > > There are a few more patches not in this patchset that deal with externs, > > test cases, etc. > > Unfortunately I don't have the bandwidth to review these in details ATM, > but I think it makes sense to have P4 be a conceptual entity in TC, and > using eBPF as the infrastructure to execute the programs. So, on that > conceptual level only: > > Acked-by: Toke Høiland-Jørgensen <toke@xxxxxxxxxx> > Thanks Toke! > [...] > > > To summarize in presence of eBPF: The debugging idea is probably still > > alive. One could dump, with proper tooling(bpftool for example), the > > loaded eBPF code and be able to check for differences. But this is not the > > interesting part. > > The concept of going back from whats in the kernel to P4 is a lot more > > difficult to implement mostly due to scoping of DSL vs general purpose. It > > may be lost. We have been discussing ways to use BTF and embedding > > annotations in the eBPF code and binary but more thought is required and we > > welcome suggestions. > > One thought on this: I don't believe there's any strict requirement that > the source lines in the "BTF lineinfo" information has to be C source > code. So if the P4 compiler can relate the generated BPF instructions > back to the original P4, couldn't it just embed the P4 program itself > (in some suitable syntax) as the lineinfo? I like it. Note, we do generate the P4 code embedded as comments in the eBPF code today. We'll look into it ;-> cheers, jamal
