Re: [RFC PATCH v2 1/7] bpf: Introduce BPF_PROG_TYPE_VNET_HASH

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Mon, Nov 20, 2023 at 12:05 AM Akihiko Odaki <akihiko.odaki@xxxxxxxxxx> wrote:
>
> On 2023/11/20 6:02, Song Liu wrote:
[...]
> >> In contrast, our intended use case is more like a normal application.
> >> So, for example, a user may download a container and run QEMU (including
> >> the BPF program) installed in the container. As such, it is nice if the
> >> ABI is stable across kernel releases, but it is not guaranteed for
> >> kfuncs. Such a use case is already covered with the eBPF steering
> >> program so I want to maintain it if possible.
> >
> > TBH, I don't think stability should be a concern for kfuncs used by QEMU.
> > Many core BPF APIs are now implemented as kfuncs: bpf_dynptr_*,
> > bpf_rcu_*, etc. As long as there are valid use cases,these kfuncs will
> > be supported.
>
> Documentation/bpf/kfuncs.rst still says:
>  > kfuncs provide a kernel <-> kernel API, and thus are not bound by any
>  > of the strict stability restrictions associated with kernel <-> user
>  > UAPIs.
>
> Is it possible to change the statement like as follows:
> "Most kfuncs provide a kernel <-> kernel API, and thus are not bound by
> any of the strict stability restrictions associated with kernel <-> user
> UAPIs. kfuncs that have same stability restrictions associated with
> UAPIs are exceptional, and must be carefully reviewed by subsystem (and
> BPF?) maintainers as any other UAPIs are."

I am afraid this is against the intention to not guarantee UAPI-level stability
for kfuncs.

Thanks,
Song





[Index of Archives]     [Linux Wireless]     [Linux Kernel]     [ATH6KL]     [Linux Bluetooth]     [Linux Netdev]     [Kernel Newbies]     [Share Photos]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Samba]     [Device Mapper]

  Powered by Linux