From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-x633.google.com (mail-pl1-x633.google.com [IPv6:2607:f8b0:4864:20::633]) by mail.toke.dk (Postfix) with ESMTPS id F0E29A2A7D3 for ; Fri, 15 Sep 2023 18:25:24 +0200 (CEST) Authentication-Results: mail.toke.dk; dkim=pass (2048-bit key; unprotected) header.d=google.com header.i=@google.com header.a=rsa-sha256 header.s=20230601 header.b=GRr5TY+v Received: by mail-pl1-x633.google.com with SMTP id d9443c01a7336-1c1ff5b741cso21409665ad.2 for ; Fri, 15 Sep 2023 09:25:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1694795123; x=1695399923; darn=xdp-project.net; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=caYAdF+ryD0kwA8cCjPq2MBqIrQhng50FRxXd+yI6AE=; b=GRr5TY+v5LuI+u2kkkv1WemhMo45NHA27Uaz4PxjvTLHP1liH5KqfOMx9VOtjP/uMK OiwjnOVn1A8UO3uYSaAHi6m+wjZUmoYoW3hFAIVwVCUy8tHovnNqbgT/PQMN4Jtn4Hl/ WmCfoGimgwfwkqQ+X+m1LFRmToJm1EGZ6zGvdMGxtGDWZxgYfYFs8y2xzr8rTmL44kZI hhM6qWYbq/jQuTBghZuEW5wT4XfVhmVgoQRVH5asc8DzMXLe0samKkQ9HvJG3MAaJ83k AlFDRnOirq35UMxX8unEeS8VclCYLFymfIs6jz4Ax4ZyUlb1uTweom2eRXkaByWX/dbu Dmow== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1694795123; x=1695399923; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=caYAdF+ryD0kwA8cCjPq2MBqIrQhng50FRxXd+yI6AE=; b=ZiHwpRN47m1/viSBU2hZS4iwKHugvYJl6Z9s5HqOFfrvZEwL2kQLsZvAZ/deHXLvs4 hE6krFJ/02RJpuKHBowCTRIhELMwDhhkuX7ON9GJrD3meEedE4NOl8NN3smQpDCyCPlW W5NzRidC6IZyZPWC5NoYsODgj+QUnjY/yIiFSXzflETttYMSJx7vHeqpQYR+2UEFUqSW 5bLwz7dHRmDgqqfmF5nabQHzt9sYVPAXHkLAnXWyp1Td48unb0gh5qBXzve9s7FxhOaN M5DT4YZjZE/lco4nfzsspP8tZt9mSFvKomr7mSUa7Bc3PJDqR0sJrvzXuvqm1mov2ibv Tjig== X-Gm-Message-State: AOJu0Yy8u3dBbHk45uUlr2L5cgK7pDByjv29TxlLQK46kPzupQMkwINu sOH9V1VC0kdaLI4CFlvo3kJRTxDiTHyv53U/Z13w8Q== X-Google-Smtp-Source: AGHT+IEKzV60ZnuywBb1gKHVgR9KDWDuvGDFHhBt5uTekInmTrCfUyNFnujdpvA7lvjBy7afBQLR+5vNV/D5OuNI9sQ= X-Received: by 2002:a17:902:cecb:b0:1c2:82e:32de with SMTP id d11-20020a170902cecb00b001c2082e32demr3094430plg.0.1694795122958; Fri, 15 Sep 2023 09:25:22 -0700 (PDT) MIME-Version: 1.0 References: <20230914210452.2588884-1-sdf@google.com> <20230914210452.2588884-3-sdf@google.com> <87edj0dxzi.fsf@intel.com> In-Reply-To: <87edj0dxzi.fsf@intel.com> From: Stanislav Fomichev Date: Fri, 15 Sep 2023 09:25:11 -0700 Message-ID: To: Vinicius Costa Gomes Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Message-ID-Hash: VBBVMOEHSOKMCX7KRVFPXBMDG5CBSQDG X-Message-ID-Hash: VBBVMOEHSOKMCX7KRVFPXBMDG5CBSQDG X-MailFrom: sdf@google.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: bpf@vger.kernel.org, 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, haoluo@google.com, jolsa@kernel.org, kuba@kernel.org, toke@kernel.org, willemb@google.com, dsahern@kernel.org, magnus.karlsson@intel.com, bjorn@kernel.org, maciej.fijalkowski@intel.com, hawk@kernel.org, yoong.siang.song@intel.com, netdev@vger.kernel.org, xdp-hints@xdp-project.net X-Mailman-Version: 3.3.8 Precedence: list Subject: [xdp-hints] Re: [PATCH bpf-next v2 2/9] xsk: add TX timestamp and TX checksum offload support List-Id: XDP hardware hints design discussion Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: On Thu, Sep 14, 2023 at 6:30=E2=80=AFPM Vinicius Costa Gomes wrote: > > Hi, > > Stanislav Fomichev writes: > > > This change actually defines the (initial) metadata layout > > that should be used by AF_XDP userspace (xsk_tx_metadata). > > The first field is flags which requests appropriate offloads, > > followed by the offload-specific fields. The supported per-device > > offloads are exported via netlink (new xsk-flags). > > > > The offloads themselves are still implemented in a bit of a > > framework-y fashion that's left from my initial kfunc attempt. > > I'm introducing new xsk_tx_metadata_ops which drivers are > > supposed to implement. The drivers are also supposed > > to call xsk_tx_metadata_request/xsk_tx_metadata_complete in > > the right places. Since xsk_tx_metadata_{request,_complete} > > are static inline, we don't incur any extra overhead doing > > indirect calls. > > > > The benefit of this scheme is as follows: > > - keeps all metadata layout parsing away from driver code > > - makes it easy to grep and see which drivers implement what > > - don't need any extra flags to maintain to keep track of what > > offloads are implemented; if the callback is implemented - the offloa= d > > is supported (used by netlink reporting code) > > > > Two offloads are defined right now: > > 1. XDP_TX_METADATA_CHECKSUM: skb-style csum_start+csum_offset > > 2. XDP_TX_METADATA_TIMESTAMP: writes TX timestamp back into metadata > > area upon completion (tx_timestamp field) > > > > The offloads are also implemented for copy mode: > > 1. Extra XDP_TX_METADATA_CHECKSUM_SW to trigger skb_checksum_help; this > > might be useful as a reference implementation and for testing > > 2. XDP_TX_METADATA_TIMESTAMP writes SW timestamp from the skb > > destructor (note I'm reusing hwtstamps to pass metadata pointer) > > > > The struct is forward-compatible and can be extended in the future > > by appending more fields. > > > > Signed-off-by: Stanislav Fomichev > > --- > > Documentation/netlink/specs/netdev.yaml | 20 +++++++ > > include/linux/netdevice.h | 27 +++++++++ > > include/linux/skbuff.h | 14 ++++- > > include/net/xdp_sock.h | 80 +++++++++++++++++++++++++ > > include/net/xdp_sock_drv.h | 13 ++++ > > include/net/xsk_buff_pool.h | 6 ++ > > include/uapi/linux/if_xdp.h | 40 +++++++++++++ > > include/uapi/linux/netdev.h | 16 +++++ > > net/core/netdev-genl.c | 12 +++- > > net/xdp/xsk.c | 39 ++++++++++++ > > net/xdp/xsk_queue.h | 2 +- > > tools/include/uapi/linux/if_xdp.h | 54 +++++++++++++++-- > > tools/include/uapi/linux/netdev.h | 15 +++++ > > 13 files changed, 330 insertions(+), 8 deletions(-) > > > > diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/ne= tlink/specs/netdev.yaml > > index 1c7284fd535b..9002b37b7676 100644 > > --- a/Documentation/netlink/specs/netdev.yaml > > +++ b/Documentation/netlink/specs/netdev.yaml > > @@ -42,6 +42,19 @@ name: netdev > > doc: > > This feature informs if netdev implements non-linear XDP buf= fer > > support in ndo_xdp_xmit callback. > > + - > > + type: flags > > + name: xsk-flags > > + render-max: true > > + entries: > > + - > > + name: tx-timestamp > > + doc: > > + HW timestamping egress packets is supported by the driver. > > + - > > + name: tx-checksum > > + doc: > > + L3 checksum HW offload is supported by the driver. > > > > attribute-sets: > > - > > @@ -68,6 +81,12 @@ name: netdev > > type: u32 > > checks: > > min: 1 > > + - > > + name: xsk-features > > + doc: Bitmask of enabled AF_XDP features. > > + type: u64 > > + enum: xsk-flags > > + enum-as-flags: true > > > > operations: > > list: > > @@ -84,6 +103,7 @@ name: netdev > > - ifindex > > - xdp-features > > - xdp-zc-max-segs > > + - xsk-features > > dump: > > reply: *dev-all > > - > > diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h > > index 0896aaa91dd7..3f02aaa30590 100644 > > --- a/include/linux/netdevice.h > > +++ b/include/linux/netdevice.h > > @@ -1647,6 +1647,31 @@ struct net_device_ops { > > struct netlink_ext_ac= k *extack); > > }; > > > > +/* > > + * This structure defines the AF_XDP TX metadata hooks for network dev= ices. > > + * The following hooks can be defined; unless noted otherwise, they ar= e > > + * optional and can be filled with a null pointer. > > + * > > + * int (*tmo_request_timestamp)(void *priv) > > + * This function is called when AF_XDP frame requested egress time= stamp. > > + * > > + * int (*tmo_fill_timestamp)(void *priv) > > + * This function is called when AF_XDP frame, that had requested > > + * egress timestamp, received a completion. The hook needs to retu= rn > > + * the actual HW timestamp. > > + * > > + * int (*tmo_request_checksum)(u16 csum_start, u16 csum_offset, void *= priv) > > + * This function is called when AF_XDP frame requested HW checksum > > + * offload. csum_start indicates position where checksumming shoul= d start. > > + * csum_offset indicates position where checksum should be stored. > > + * > > + */ > > +struct xsk_tx_metadata_ops { > > + void (*tmo_request_timestamp)(void *priv); > > + u64 (*tmo_fill_timestamp)(void *priv); > > + void (*tmo_request_checksum)(u16 csum_start, u16 csum_offset, = void *priv); > > +}; > > + > > /** > > * enum netdev_priv_flags - &struct net_device priv_flags > > * > > @@ -1835,6 +1860,7 @@ enum netdev_ml_priv_type { > > * @netdev_ops: Includes several pointers to callbacks, > > * if one wants to override the ndo_*() functions > > * @xdp_metadata_ops: Includes pointers to XDP metadata callbac= ks. > > + * @xsk_tx_metadata_ops: Includes pointers to AF_XDP TX metadata c= allbacks. > > * @ethtool_ops: Management operations > > * @l3mdev_ops: Layer 3 master device operations > > * @ndisc_ops: Includes callbacks for different IPv6 neighbour > > @@ -2091,6 +2117,7 @@ struct net_device { > > unsigned long long priv_flags; > > const struct net_device_ops *netdev_ops; > > const struct xdp_metadata_ops *xdp_metadata_ops; > > + const struct xsk_tx_metadata_ops *xsk_tx_metadata_ops; > > int ifindex; > > unsigned short gflags; > > unsigned short hard_header_len; > > diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h > > index 4174c4b82d13..444d35dcd690 100644 > > --- a/include/linux/skbuff.h > > +++ b/include/linux/skbuff.h > > @@ -566,6 +566,15 @@ struct ubuf_info_msgzc { > > int mm_account_pinned_pages(struct mmpin *mmp, size_t size); > > void mm_unaccount_pinned_pages(struct mmpin *mmp); > > > > +/* Preserve some data across TX submission and completion. > > + * > > + * Note, this state is stored in the driver. Extending the layout > > + * might need some special care. > > + */ > > +struct xsk_tx_metadata_compl { > > + __u64 *tx_timestamp; > > +}; > > + > > /* This data is invariant across clones and lives at > > * the end of the header data, ie. at skb->end. > > */ > > @@ -578,7 +587,10 @@ struct skb_shared_info { > > /* Warning: this field is not always filled in (UFO)! */ > > unsigned short gso_segs; > > struct sk_buff *frag_list; > > - struct skb_shared_hwtstamps hwtstamps; > > + union { > > + struct skb_shared_hwtstamps hwtstamps; > > + struct xsk_tx_metadata_compl xsk_meta; > > + }; > > unsigned int gso_type; > > u32 tskey; > > > > diff --git a/include/net/xdp_sock.h b/include/net/xdp_sock.h > > index 10993a05d220..c438c614a8d0 100644 > > --- a/include/net/xdp_sock.h > > +++ b/include/net/xdp_sock.h > > @@ -90,6 +90,74 @@ int xsk_generic_rcv(struct xdp_sock *xs, struct xdp_= buff *xdp); > > int __xsk_map_redirect(struct xdp_sock *xs, struct xdp_buff *xdp); > > void __xsk_map_flush(void); > > > > +/** > > + * xsk_tx_metadata_to_compl - Save enough relevant metadata informati= on > > + * to perform tx completion in the future. > > + * @meta: pointer to AF_XDP metadata area > > + * @compl: pointer to output struct xsk_tx_metadata_to_compl > > + * > > + * This function should be called by the networking device when > > + * it prepares AF_XDP egress packet. The value of @compl should be st= ored > > + * and passed to xsk_tx_metadata_complete upon TX completion. > > + */ > > +static inline void xsk_tx_metadata_to_compl(struct xsk_tx_metadata *me= ta, > > + struct xsk_tx_metadata_compl = *compl) > > One of my systems didn't have the config XDP_SOCKETS enabled, and found > some issues: > > This function is not defined when XDP_SOCKETS is disabled, got a > compilation error. > > > +{ > > + if (!meta) > > + return; > > + > > + if (meta->flags & XDP_TX_METADATA_TIMESTAMP) > > + compl->tx_timestamp =3D &meta->completion.tx_timestamp; > > + else > > + compl->tx_timestamp =3D NULL; > > +} > > + > > +/** > > + * xsk_tx_metadata_request - Evaluate AF_XDP TX metadata at submissio= n > > + * and call appropriate xsk_tx_metadata_ops operation. > > + * @meta: pointer to AF_XDP metadata area > > + * @ops: pointer to struct xsk_tx_metadata_ops > > + * @priv: pointer to driver-private aread > > + * > > + * This function should be called by the networking device when > > + * it prepares AF_XDP egress packet. > > + */ > > +static inline void xsk_tx_metadata_request(const struct xsk_tx_metadat= a *meta, > > + const struct xsk_tx_metadata_o= ps *ops, > > + void *priv) > > +{ > > + if (!meta) > > + return; > > + > > + if (ops->tmo_request_timestamp) > > + if (meta->flags & XDP_TX_METADATA_TIMESTAMP) > > + ops->tmo_request_timestamp(priv); > > + > > + if (ops->tmo_request_checksum) > > + if (meta->flags & XDP_TX_METADATA_CHECKSUM) > > + ops->tmo_request_checksum(meta->csum_start, meta-= >csum_offset, priv); > > +} > > + > > +/** > > + * xsk_tx_metadata_complete - Evaluate AF_XDP TX metadata at completi= on > > + * and call appropriate xsk_tx_metadata_ops operation. > > + * @compl: pointer to completion metadata produced from xsk_tx_metada= ta_to_compl > > + * @ops: pointer to struct xsk_tx_metadata_ops > > + * @priv: pointer to driver-private aread > > + * > > + * This function should be called by the networking device upon > > + * AF_XDP egress completion. > > + */ > > +static inline void xsk_tx_metadata_complete(struct xsk_tx_metadata_com= pl *compl, > > + const struct xsk_tx_metadata_= ops *ops, > > + void *priv) > > +{ > > + if (!compl) > > + return; > > + > > + *compl->tx_timestamp =3D ops->tmo_fill_timestamp(priv); > > +} > > + > > #else > > > > static inline int xsk_generic_rcv(struct xdp_sock *xs, struct xdp_buff= *xdp) > > @@ -106,6 +174,18 @@ static inline void __xsk_map_flush(void) > > { > > } > > > > +static inline void xsk_tx_metadata_request(struct xsk_tx_metadata *met= a, > > + const struct xsk_tx_metadata_o= ps *ops, > > + void *priv) > > +{ > > +} > > + > > +static inline void xsk_tx_metadata_complete(struct xsk_tx_metadata_com= p *compl, > > typo here: should be 'struct xsk_tx_metadata_compl'. > > Just so you are aware of these (very) minor issues for the next version. > > I enabled XDP_SOCKETS and will take a better look. Thank you, will take a look. There are a bunch of bot build errors that look similar as well.