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Date:   Mon, 22 May 2023 14:24:38 +0100
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Subject: Re: [PATCH bpf-next v2] bpftool: specify XDP Hints ifname when
 loading program
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To:     Larysa Zaremba <larysa.zaremba@intel.com>
Cc:     Stanislav Fomichev <sdf@google.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <martin.lau@linux.dev>,
        Song Liu <song@kernel.org>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>, Hao Luo <haoluo@google.com>,
        Jiri Olsa <jolsa@kernel.org>, bpf@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        =?UTF-8?Q?Niklas_S=c3=b6derlund?= <niklas.soderlund@corigine.com>
References: <20230517160103.1088185-1-larysa.zaremba@intel.com>
From:   Quentin Monnet <quentin@isovalent.com>
In-Reply-To: <20230517160103.1088185-1-larysa.zaremba@intel.com>
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2023-05-17 18:01 UTC+0200 ~ Larysa Zaremba <larysa.zaremba@intel.com>
> Add ability to specify a network interface used to resolve
> XDP Hints kfuncs when loading program through bpftool.
> 
> Usage:
>   bpftool prog load [...] xdpmeta_dev <ifname>
> 
> Writing just 'dev <ifname>' instead of 'xdpmeta_dev' is a very probable
> mistake that results in not very descriptive errors,
> so 'bpftool prog load [...] dev <ifname>' syntax becomes deprecated,
> followed by 'bpftool map create [...] dev <ifname>' for consistency.
> 
> Now, to offload program, execute:
>   bpftool prog load [...] offload_dev <ifname>
> 
> To offload map:
>   bpftool map create [...] offload_dev <ifname>
> 
> 'dev <ifname>' still performs offloading in the commands above, but now
> triggers a warning and is excluded from bash completion.
> 
> 'xdpmeta_dev' and 'offload_dev' are mutually exclusive options, because
> 'xdpmeta_dev' basically makes a program device-bound without loading it
> onto the said device. For now, offloaded programs cannot use XDP hints [0],
> but if this changes, using 'offload_dev <ifname>' should cover this case.
> 
> [0] https://lore.kernel.org/bpf/a5a636cc-5b03-686f-4be0-000383b05cfc@linux.dev
> 
> Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>

Thanks!