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[35.245.174.172]) by smtp.gmail.com with ESMTPSA id y26-20020a0c9a9a000000b00632191a70a2sm1730379qvd.103.2023.07.19.14.42.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 19 Jul 2023 14:42:04 -0700 (PDT) Date: Wed, 19 Jul 2023 17:42:04 -0400 From: Willem de Bruijn To: Larysa Zaremba , bpf@vger.kernel.org Message-ID: <64b858ac9edd3_2849c129476@willemb.c.googlers.com.notmuch> In-Reply-To: <20230719183734.21681-13-larysa.zaremba@intel.com> References: <20230719183734.21681-1-larysa.zaremba@intel.com> <20230719183734.21681-13-larysa.zaremba@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Message-ID-Hash: DCPH4JW2P2BZSE4KJVNUW3MZGNS3ZUOQ X-Message-ID-Hash: DCPH4JW2P2BZSE4KJVNUW3MZGNS3ZUOQ X-MailFrom: willemdebruijn.kernel@gmail.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: Larysa Zaremba , ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, song@kernel.org, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, David Ahern , Jakub Kicinski , Willem de Bruijn , Jesper Dangaard Brouer , Anatoly Burakov , Alexander Lobakin , Magnus Karlsson , Maryam Tahhan , xdp-hints@xdp-project.net, netdev@vger.kernel.org X-Mailman-Version: 3.3.8 Precedence: list Subject: [xdp-hints] Re: [PATCH bpf-next v3 12/21] xdp: Add checksum hint List-Id: XDP hardware hints design discussion Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: Larysa Zaremba wrote: > Implement functionality that enables drivers to expose to XDP code checksum > information that consists of: > > - Checksum status - bitfield that consists of > - number of consecutive validated checksums. This is almost the same as > csum_level in skb, but starts with 1. Enum names for those bits still > use checksum level concept, so it is less confusing for driver > developers. > - Is checksum partial? This bit cannot coexist with any other > - Is there a complete checksum available? > - Additional checksum data, a union of: > - checksum start and offset, if checksum is partial > - complete checksum, if available > > Signed-off-by: Larysa Zaremba > --- > Documentation/networking/xdp-rx-metadata.rst | 3 ++ > include/linux/netdevice.h | 3 ++ > include/net/xdp.h | 46 ++++++++++++++++++++ > kernel/bpf/offload.c | 2 + > net/core/xdp.c | 23 ++++++++++ > 5 files changed, 77 insertions(+) > > diff --git a/Documentation/networking/xdp-rx-metadata.rst b/Documentation/networking/xdp-rx-metadata.rst > index ea6dd79a21d3..7f056a44f682 100644 > --- a/Documentation/networking/xdp-rx-metadata.rst > +++ b/Documentation/networking/xdp-rx-metadata.rst > @@ -26,6 +26,9 @@ metadata is supported, this set will grow: > .. kernel-doc:: net/core/xdp.c > :identifiers: bpf_xdp_metadata_rx_vlan_tag > > +.. kernel-doc:: net/core/xdp.c > + :identifiers: bpf_xdp_metadata_rx_csum > + > An XDP program can use these kfuncs to read the metadata into stack > variables for its own consumption. Or, to pass the metadata on to other > consumers, an XDP program can store it into the metadata area carried > diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h > index 1749f4f75c64..4f6da36ac123 100644 > --- a/include/linux/netdevice.h > +++ b/include/linux/netdevice.h > @@ -1660,6 +1660,9 @@ struct xdp_metadata_ops { > enum xdp_rss_hash_type *rss_type); > int (*xmo_rx_vlan_tag)(const struct xdp_md *ctx, u16 *vlan_tci, > __be16 *vlan_proto); > + int (*xmo_rx_csum)(const struct xdp_md *ctx, > + enum xdp_csum_status *csum_status, > + union xdp_csum_info *csum_info); > }; > > /** > diff --git a/include/net/xdp.h b/include/net/xdp.h > index 89c58f56ffc6..2b7a7d678ff4 100644 > --- a/include/net/xdp.h > +++ b/include/net/xdp.h > @@ -391,6 +391,8 @@ void xdp_attachment_setup(struct xdp_attachment_info *info, > bpf_xdp_metadata_rx_hash) \ > XDP_METADATA_KFUNC(XDP_METADATA_KFUNC_RX_VLAN_TAG, \ > bpf_xdp_metadata_rx_vlan_tag) \ > + XDP_METADATA_KFUNC(XDP_METADATA_KFUNC_RX_CSUM, \ > + bpf_xdp_metadata_rx_csum) \ > > enum { > #define XDP_METADATA_KFUNC(name, _) name, > @@ -448,6 +450,50 @@ enum xdp_rss_hash_type { > XDP_RSS_TYPE_L4_IPV6_SCTP_EX = XDP_RSS_TYPE_L4_IPV6_SCTP | XDP_RSS_L3_DYNHDR, > }; > > +union xdp_csum_info { > + /* Checksum referred to by ``csum_start + csum_offset`` is considered > + * valid, but was never calculated, TX device has to do this, > + * starting from csum_start packet byte. > + * Any preceding checksums are also considered valid. > + * Available, if ``status == XDP_CHECKSUM_PARTIAL``. > + */ > + struct { > + u16 csum_start; > + u16 csum_offset; > + }; > + > + /* Checksum, calculated over the whole packet. > + * Available, if ``status & XDP_CHECKSUM_COMPLETE``. > + */ > + u32 checksum; > +}; > + > +enum xdp_csum_status { > + /* HW had parsed several transport headers and validated their > + * checksums, same as ``CHECKSUM_UNNECESSARY`` in ``sk_buff``. > + * 3 least significat bytes contain number of consecutive checksum, typo: significant (I did not scan for typos, just came across this when trying to understand the skb->csum_level + 1 trick. Probably good to run a spell check). > + * starting with the outermost, reported by hardware as valid. > + * ``sk_buff`` checksum level (``csum_level``) notation is provided > + * for driver developers. > + */ > + XDP_CHECKSUM_VALID_LVL0 = 1, /* 1 outermost checksum */ > + XDP_CHECKSUM_VALID_LVL1 = 2, /* 2 outermost checksums */ > + XDP_CHECKSUM_VALID_LVL2 = 3, /* 3 outermost checksums */ > + XDP_CHECKSUM_VALID_LVL3 = 4, /* 4 outermost checksums */ > + XDP_CHECKSUM_VALID_NUM_MASK = GENMASK(2, 0), > + XDP_CHECKSUM_VALID = XDP_CHECKSUM_VALID_NUM_MASK, > + > + /* Occurs if packet is sent virtually (between Linux VMs / containers) > + * This status cannot coexist with any other. > + * Refer to ``csum_start`` and ``csum_offset`` in ``xdp_csum_info`` > + * for more information. > + */ > + XDP_CHECKSUM_PARTIAL = BIT(3), > + > + /* Checksum, calculated over the entire packet is provided */ > + XDP_CHECKSUM_COMPLETE = BIT(4), > +}; > + > #ifdef CONFIG_NET > u32 bpf_xdp_metadata_kfunc_id(int id); > bool bpf_dev_bound_kfunc_id(u32 btf_id); > diff --git a/kernel/bpf/offload.c b/kernel/bpf/offload.c > index 986e7becfd42..f60a6add5273 100644 > --- a/kernel/bpf/offload.c > +++ b/kernel/bpf/offload.c > @@ -850,6 +850,8 @@ void *bpf_dev_bound_resolve_kfunc(struct bpf_prog *prog, u32 func_id) > p = ops->xmo_rx_hash; > else if (func_id == bpf_xdp_metadata_kfunc_id(XDP_METADATA_KFUNC_RX_VLAN_TAG)) > p = ops->xmo_rx_vlan_tag; > + else if (func_id == bpf_xdp_metadata_kfunc_id(XDP_METADATA_KFUNC_RX_CSUM)) > + p = ops->xmo_rx_csum; > out: > up_read(&bpf_devs_lock); > > diff --git a/net/core/xdp.c b/net/core/xdp.c > index 8b55419d332e..d4ea54046afc 100644 > --- a/net/core/xdp.c > +++ b/net/core/xdp.c > @@ -772,6 +772,29 @@ __bpf_kfunc int bpf_xdp_metadata_rx_vlan_tag(const struct xdp_md *ctx, > return -EOPNOTSUPP; > } > > +/** > + * bpf_xdp_metadata_rx_csum - Get checksum status with additional info. > + * @ctx: XDP context pointer. > + * @csum_status: Destination for checksum status. > + * @csum_info: Destination for complete checksum or partial checksum offset. > + * > + * Status (@csum_status) is a bitfield that informs, what checksum > + * processing was performed. Additional results of such processing, > + * such as complete checksum or partial checksum offsets, > + * are passed as info (@csum_info). > + * > + * Return: > + * * Returns 0 on success or ``-errno`` on error. > + * * ``-EOPNOTSUPP`` : device driver doesn't implement kfunc > + * * ``-ENODATA`` : Checksum status is unknown > + */ > +__bpf_kfunc int bpf_xdp_metadata_rx_csum(const struct xdp_md *ctx, > + enum xdp_csum_status *csum_status, > + union xdp_csum_info *csum_info) > +{ > + return -EOPNOTSUPP; > +} > + > __diag_pop(); > > BTF_SET8_START(xdp_metadata_kfunc_ids) > -- > 2.41.0 >