Re: [Qemu-devel] [RFC 0/1] Add BPF suuport to Qemu

[Peter Maydell]

On 19 June 2018 at 14:21, Sameeh Jubran <address@hidden> wrote:
> From: Sameeh Jubran <address@hidden>
>
> The Berkeley Packet Filter has been in the kernel for a while now and I
> think it is time that it is introduced to Qemu. This patch is an
> infrastructure for any future usage of the BPF in Qemu.
>
> It is important to note that the tun driver had started supporting using
> BPF programs through ioctls (TUNSETSTEERINGEBPF and TUNSETFILTEREBPF).
>
> At first, instead of adding the syscall wrappers, I wanted to integrate libbpf
> library which resides in the Linux source tree under tools/lib/bpf. It appears
> to be that by default it compiles to x64 on x64 arch - which can't be
> integrated into Qemu  - and my attempts to compile the 32 bit versions have
> failed. What's more interesting is that the vendors don't provide this library
> in any package, which makes this library a nasty dependency.
>
> Please share your thoughts :)

My question is -- what's the use case? This patchset seems
to just add the bpf_syscall.c code to QEMU but without any
changes to actually use the new functionality. It's hard
to evaluate whether something's a worthwhile addition integrated
in the right way without the code changes that make use of it...

thanks
-- PMM