Re: [RFC PATCH 1/5] ebpf: Added eBPF initialization by fds and map update.

[Andrew Melnichenko]

Hi all,

On Thu, Mar 30, 2023 at 10:10 AM Daniel P. Berrangé <berrange@redhat.com> wrote:
>
> On Thu, Mar 30, 2023 at 02:53:16PM +0800, Jason Wang wrote:
> > On Thu, Mar 30, 2023 at 8:33 AM Andrew Melnychenko <andrew@daynix.com> 
> > wrote:
> > >
> > > Changed eBPF map updates through mmaped array.
> > > Mmaped arrays provide direct access to map data.
> > > It should omit using bpf_map_update_elem() call,
> > > which may require capabilities that are not present.
> >
> > This requires kernel support, so after this change, eBPF based RSS
> > doesn't work on old kernels that only support syscall based map
> > updating.
>

It would not work either - bpf_map_update_elem() requires BPF capabilities.

> What kernel version is the cut off ?

If I'm not mistaken - something like kernel 5.5<.
But in any case - the RSS eBPF program is quite big and would require features
like jumpsback.
So, on old kernels, it would not load.

>
>
> With regards,
> Daniel
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