> -----Original Message----- > From: David Vernet <void@xxxxxxxxxxxxx> > Sent: Tuesday, May 23, 2023 9:32 AM > To: Dave Thaler <dthaler@xxxxxxxxxxxxx> > Cc: Jose E. Marchesi <jemarch@xxxxxxx>; bpf@xxxxxxxx; bpf > <bpf@xxxxxxxxxxxxxxx>; Erik Kline <ek.ietf@xxxxxxxxx>; Suresh Krishnan > (sureshk) <sureshk@xxxxxxxxx>; Christoph Hellwig <hch@xxxxxxxxxxxxx>; > Alexei Starovoitov <ast@xxxxxxxxxx> > Subject: Re: [Bpf] IETF BPF working group draft charter > > On Thu, May 18, 2023 at 07:42:11PM +0000, Dave Thaler wrote: > > Jose E. Marchesi <jemarch@xxxxxxx> wrote: > > > I would think that the way the x86_64, aarch64, risc-v, sparc, mips, > > > powerpc architectures, along with their variants, handle their ELF > > > extensions and psABI, ensures interoperability good enough for the > problem at hand, but ok. > > > I'm definitely not an expert in these matters. > > > > I am not familiar enough with those to make any comment about that. > > Hi Dave, > > Taking a step back here, perhaps we need to think about all of this more > generically as "ABI", rather than ELF "extensions", "bindings", etc. In my > opinion this would include, at a minimum, the following items from the current > proposed WG charter: > > * the eBPF bindings for the ELF executable file format, > > * the platform support ABI, including calling convention, linker > requirements, and relocations, > > As far as I know (please correct me if I'm wrong), there isn't really a precedence > for standardizing ABIs like this. For example, x86 calling conventions are not > standardized. Solaris, Linux, FreeBSD, macOS, etc all follow the System V > AMD64 ABI, but Microsoft of course does not. As Jose pointed out, such > standards extensions do not exist for psABI ELF extensions for various > architectures either. > > While it may be that we do end up needing to standardize these ABIs for BPF, > I'm beginning to think that we should just remove them from the current WG > charter, and consider standardizing them at a later time if it's clear that it's > actually necessary. I think this is especially true given that we don't seem to be > getting any closer to having consensus, and that we're very short on time given > that Erik is going to be proposing the charter to the rest of the ADs in just two > days on 5/25. > > Thanks, > David I can tell you it's very important to those who work on the ebpf-for-windows project that the ELF format is common between Linux and Windows so that tools like llvm-objdump and bpftool and other BPF-specific ELF parsing tools work for both Linux and Windows. We don't want Windows to diverge. As such, I feel strongly that it is a requirement to be standardized right away. Hence I would not want this removed from the charter unless there's an effort to do it somewhere else right away, which would seem to increase the coordination burden. Dave
