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[37.182.17.175]) by smtp.gmail.com with ESMTPSA id x1sm12109403wru.40.2021.12.06.12.03.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 06 Dec 2021 12:03:59 -0800 (PST) Date: Mon, 6 Dec 2021 21:03:58 +0100 From: Lorenzo Bianconi To: Zvi Effron Cc: Jesper Dangaard Brouer , Lorenzo Bianconi , bpf@vger.kernel.org, netdev@vger.kernel.org, brouer@redhat.com, davem@davemloft.net, kuba@kernel.org, ast@kernel.org, daniel@iogearbox.net, shayagr@amazon.com, john.fastabend@gmail.com, dsahern@kernel.org, echaudro@redhat.com, jasowang@redhat.com, alexander.duyck@gmail.com, saeed@kernel.org, maciej.fijalkowski@intel.com, magnus.karlsson@intel.com, tirthendu.sarkar@intel.com, toke@redhat.com Subject: Re: [PATCH v19 bpf-next 23/23] xdp: disable XDP_REDIRECT for xdp multi-buff Message-ID: References: <88f9b4e9-9074-a507-426d-7c947f1e2b13@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="qbA3iRlZxQw4vN4L" Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org --qbA3iRlZxQw4vN4L Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable > On Mon, Dec 6, 2021 at 11:11 AM Jesper Dangaard Brouer > wrote: > > > > On 30/11/2021 12.53, Lorenzo Bianconi wrote: > > > XDP_REDIRECT is not fully supported yet for xdp multi-buff since not > > > all XDP capable drivers can map non-linear xdp_frame in ndo_xdp_xmit > > > so disable it for the moment. > > > > > > Signed-off-by: Lorenzo Bianconi > > > --- > > > net/core/filter.c | 7 +++++++ > > > 1 file changed, 7 insertions(+) > > > > > > diff --git a/net/core/filter.c b/net/core/filter.c > > > index b70725313442..a87d835d1122 100644 > > > --- a/net/core/filter.c > > > +++ b/net/core/filter.c > > > @@ -4189,6 +4189,13 @@ int xdp_do_redirect(struct net_device *dev, st= ruct xdp_buff *xdp, > > > struct bpf_map *map; > > > int err; > > > > > > + /* XDP_REDIRECT is not fully supported yet for xdp multi-buff s= ince > > > + * not all XDP capable drivers can map non-linear xdp_frame in > > > + * ndo_xdp_xmit. > > > + */ > > > + if (unlikely(xdp_buff_is_mb(xdp))) > > > + return -EOPNOTSUPP; > > > + > > > > This approach also exclude 'cpumap' use-case, which you AFAIK have added > > MB support for in this patchset. > > > > Generally this check is hopefully something we can remove again, once > > drivers add MB ndo_xdp_xmit support. > > >=20 > What happens in the future when a new driver is added without (in its int= ial > version) MB ndo_xdp_xmit support? Is MB support for ndo_xdp_xmit going to= be a > requirement for a driver (with ndo_xdp_xmit) to be accepted to the kernel? I think the optimal solution would be export the driver XDP capabilities (A= FAIK there is an ogoing effort for this, but it is not available yet). >=20 > I'm not arguing against removing this check in the future, I'm just wonde= ring > if we need a different mechanism than outright prohibiting XDP_REDIRECT w= ith MB > to protect against the redirected device not having MB support? >=20 > > > > > ri->map_id =3D 0; /* Valid map id idr range: [1,INT_MAX[ */ > > > ri->map_type =3D BPF_MAP_TYPE_UNSPEC; > > > > > > > > >=20 --qbA3iRlZxQw4vN4L Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQTquNwa3Txd3rGGn7Y6cBh0uS2trAUCYa5srgAKCRA6cBh0uS2t rBbMAQC+gqYQi8eaFZnyxyFJyEYU9JbyfPSutoB6IViPVE9OvgEAtddmv3l5L4SZ kt82g41U8ODMemPqhlRNQZR1DlLiFwk= =oZbs -----END PGP SIGNATURE----- --qbA3iRlZxQw4vN4L--