On Mon, Jan 15, 2018 at 03:07:25PM +0100, Daniel Borkmann wrote: > On 01/15/2018 01:27 PM, Jiong Wang wrote: > >> On Fri, 12 Jan 2018 12:31:15 +0100, Daniel Borkmann wrote: > [...] > >>> Given we know when ifindex is 0, then its always host JITed and the > >>> current approach with bfd_openr() works fine, and if ifindex is non-0 > >>> it is /always/ device offloaded to the one bound in the ifindex so > >>> JIT dump will be specific to that device only and never host one. Not > >>> at all opposed to extending uapi, just a question on my side to get a > >>> better understanding first wrt arch string (maybe rough but complete > >>> patch with nfp + bpftool bits might help too). > >> I was advocating for full separate set of fields, Jiong was trying for > >> a reuse, and we sort of met in the middle :) Depends on how one looks > >> at the definition of the jited_prog_insn field, old user space is not > >> guaranteed to pay attention to ifindex. We will drop the arch and reuse > >> host fields if that's the direction you're leaning in. > > > > I also want to make sure adding new "jited_image" and "jited_len" is the > > correct approach. > > I think it's fine. > > > Was thinking to reusing exsiting fields for host jit, i.e > > bpf_prog->jited_len and bpf_prog->aux->jited_data, but different offload > > targets might have different structure for "jited_data" that we need new > > call back to parse it, also I feel keep host fields clean for host JIT > > only might help preventing code logic for host and offload interleaving > > with each other, so had gone with adding new fields. > > Agree, one thing less to worry since this also ties into kallsyms, etc.
why would bytes in jited_prog_insns conflict with kallsyms ? I also agree that adding two extra fields for 'offloaded_prog + len' is probably cleanest. > Ok, lets stick with the current RFC, they seem to be the cleanest approach > overall with having offload_arch_name[] in the uapi and only filled by > driver JITs (and not host JITs). I don't like string based interfaces especially when strings are used by tools to compare with other strings. imo strings are only good for humans to read. I think returning ifindex is already enough. From it the tool can get pci id which is the most accurate identification of the hw.
