From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B19564A4984 for ; Fri, 11 Sep 2026 17:13:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789146800; cv=none; b=f/MIwlVGmnfJtan5zJO0Au9PoSAv3zSPaX5c4L37c4w7/qsYMnsOT7MAVJAJOZa6uS4+7HC9TzRL24hYV9HNaw9JvZmC4mow2SHIS9B/reQDHbig6UQk0Pl/EIkM+gZktSH5xD18UJnTiFvRqKH+b8QYfYghRNvicz38c6f86xA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789146800; c=relaxed/simple; bh=yCOqz1KVdn1nYma1pnvLTHPEVZY1IZ94IrvJXtS0eJk=; h=Subject:From:To:Cc:Date:Message-ID:In-Reply-To:References: Content-Type:MIME-Version; b=uHyUx2bHupjCHMLZm3wNuSYtb84iQDmVNHgR6q643X4FycYox07N837W8XVaCR1dnbp/DtwwrJu+Yo5KzlCdS8sBCkxIzhbJu2gN+GdyLMBTye7zcgA6LCtCzXiTsTTpTHBZrFhAm6N3UnOEpzf0LFwgynUOAO9QBRK5txhp8E4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RXVVpTgw; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="RXVVpTgw" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D8EB01F000FF; Fri, 11 Sep 2026 17:13:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789146798; bh=keDdM7EGPb3KUqiXlaS7/OWnlI9UeCSF1pGZAHV9K+w=; h=Subject:From:To:Cc:Date:In-Reply-To:References; b=RXVVpTgwlJ2gLGXA4tA49a40lCMvvrvzycHYgb7UlgHUpvn3o98OupqdFcQSiYKlR 5GmwhgOWWtvc0EuDd/GC6F/Xecfzm7A0AACsUhDknRKcYl+Lyfxo37PSEoiiFqfgyf Pn8noTp4/GhPOb2GoImVFBbfnfBY8NmJncFXTWkwt8aAtD00V9E2r19Fv75j4FOqNg YJJcY8i+PaoznVgWmHRUOOH8uappV5cO3fL1Spw+ufYGIhKlQs0LiheD5Brk9DiDZz DUPLJhlGDyaOyLwTkJC4mwbVVhMuUi7IRAwvB5ierNc5jZDjk7P8cUsCAeIk1E6SGN oBDiO0t4sJwMQ== Subject: Re: [PATCH net-next v9 4/7] idpf: support pacing offload From: netdev-bot+sashiko@kernel.org To: willemdebruijn.kernel@gmail.com Cc: netdev@vger.kernel.org, davem@davemloft.net, kuba@kernel.org, edumazet@google.com, pabeni@redhat.com, horms@kernel.org, andrew+netdev@lunn.ch, willemb@google.com Date: Fri, 11 Sep 2026 17:13:17 +0000 Message-ID: <178914679743.219967.4781990764758262872@kernel.org> In-Reply-To: <20260910171131.2532487-5-willemdebruijn.kernel@gmail.com> References: <20260910171131.2532487-5-willemdebruijn.kernel@gmail.com> X-sashiko-severity: High Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Thank you for your contribution! Sashiko AI review found 4 potential issue(s) to consider: Critical: 0 · High: 1 · Medium: 1 · Low: 2 - [High] idpf advertises a non-zero netdev->max_pacing_offload_horizon (and therefore programs absolute CLOCK_TAI departure times into the… - [Medium] The EDT horizon advertised to the networking core is taken verbatim from firmware and only bounds-checked against U32_MAX, while… - [Low] idpf_vport_set_pacing_offload() writes netdev->max_pacing_offload_horizon (idpf_lib.c:832) from the… - [Low] In idpf_send_get_edt_caps_msg() the firmware-supplied granularity is a u64 (gran_ns = le64_to_cpu(caps.tstamp_granularity_ns)) but is… -- idpf: support pacing offload This adds EDT (earliest departure time) support to idpf: EDT capabilities are negotiated over virtchnl, the negotiated horizon is published as netdev->max_pacing_offload_horizon, and skb->tstamp is programmed into the 23-bit timestamp field of the flow scheduling Tx descriptor. A few questions below on the capability gating and on the horizon encoding. > diff --git a/drivers/net/ethernet/intel/idpf/idpf_lib.c b/drivers/net/ethernet/intel/idpf/idpf_lib.c > index 827c795afcb62..cd1b173e3b276 100644 > --- a/drivers/net/ethernet/intel/idpf/idpf_lib.c > +++ b/drivers/net/ethernet/intel/idpf/idpf_lib.c > @@ -817,6 +817,21 @@ static void idpf_attach_and_open(struct idpf_adapter *adapter) > } > } > > +static void idpf_vport_set_pacing_offload(struct idpf_vport *vport, > + struct net_device *netdev) > +{ > + struct idpf_adapter *adapter = vport->adapter; > + u32 max_horizon = 0; > + > + if (adapter->edt_caps.time_horizon_ns && > + idpf_is_queue_model_split(vport->dflt_qv_rsrc.txq_model) && > + !idpf_is_cap_ena(adapter, IDPF_OTHER_CAPS, > + VIRTCHNL2_CAP_SPLITQ_QSCHED)) > + max_horizon = adapter->edt_caps.time_horizon_ns; > + [Severity: High] The commit message says: Negotiate the feature with the device using virtchnl. Support is conditional on ... - PTP to ensure the NIC clock is synced to CLOCK_TAI. Where is that PTP condition implemented? idpf_vport_set_pacing_offload() gates only on adapter->edt_caps.time_horizon_ns, split txq model and flow scheduling. It does not consult VIRTCHNL2_CAP_PTP, adapter->ptp, or the result of idpf_ptp_init(). In idpf_vc_core_init() the EDT negotiation is gated only on VIRTCHNL2_CAP_EDT and runs before idpf_ptp_init(), whose failure is deliberately non-fatal: err = idpf_ptp_init(adapter); if (err) pci_err(adapter->pdev, "PTP init failed, err=%pe\n", ERR_PTR(err)); So with a control plane that advertises EDT but not PTP, or when idpf_ptp_get_caps()/clock creation fails, edt_caps.time_horizon_ns stays non-zero and the horizon is still published. With CONFIG_PTP_1588_CLOCK=n the stub in idpf_ptp.h returns success while leaving adapter->ptp NULL: static inline int idpf_ptp_init(struct idpf_adapter *adapter) { return 0; } In that build there is no PHC at all and no way for userspace to steer the device clock, yet pacing offload remains advertised and idpf_tx_splitq_set_txtime() keeps writing host CLOCK_TAI values into the descriptor. Should the helper also require a working PTP clock, or should the commit message drop the PTP claim? Related: the device clock is seeded from CLOCK_REALTIME in idpf_ptp_init(): ts = ktime_to_timespec64(ktime_get_real()); err = idpf_ptp_settime64(&adapter->ptp->info, &ts); while the new Tx path converts everything to CLOCK_TAI. Is the epoch assumed by the descriptor only correct after an external synchronizer has corrected the PHC? > + WRITE_ONCE(netdev->max_pacing_offload_horizon, max_horizon); > +} > + [Severity: Low] Should this write be done under rtnl_lock()? The RTNL side reads the same field with a plain load in validate_linkmsg() before do_setlink() sets dev->pacing_offload: net/core/rtnetlink.c:validate_linkmsg() { if (nla_get_u32(tb[IFLA_PACING_OFFLOAD]) && !dev->max_pacing_offload_horizon) { ... } idpf_cfg_netdev() is reached from idpf_init_task with no RTNL held, and on the reset path it re-runs the helper on an already registered netdev, so an "ip link set dev X pacing_offload on" validated against a non-zero horizon can be followed immediately by the driver zeroing it. That also leaves dev->pacing_offload set with max_pacing_offload_horizon == 0, which is then dumped to userspace as IFLA_PACING_OFFLOAD=1 together with IFLA_MAX_PACING_OFFLOAD_HORIZON=0. Should the driver clear dev->pacing_offload when the horizon drops to 0? > /** > * idpf_cfg_netdev - Allocate, configure and register a netdev > * @vport: main vport structure > @@ -850,6 +865,8 @@ static int idpf_cfg_netdev(struct idpf_vport *vport) > np->max_tx_hdr_size = idpf_get_max_tx_hdr_size(adapter); > vport->netdev = netdev; > > + idpf_vport_set_pacing_offload(vport, netdev); > + > return idpf_init_mac_addr(vport, netdev); > } > [ ... ] > diff --git a/drivers/net/ethernet/intel/idpf/idpf_txrx.c b/drivers/net/ethernet/intel/idpf/idpf_txrx.c > index 4311ffa30bb18..215a62161a049 100644 > --- a/drivers/net/ethernet/intel/idpf/idpf_txrx.c > +++ b/drivers/net/ethernet/intel/idpf/idpf_txrx.c [ ... ] > @@ -3011,6 +3017,63 @@ static bool idpf_tx_splitq_need_re(struct idpf_tx_queue *tx_q) > return gap >= IDPF_TX_SPLITQ_RE_MIN_GAP; > } > > +static void idpf_tx_splitq_set_txtime(const struct sk_buff *skb, > + const struct idpf_tx_queue *tx_q, > + struct idpf_tx_splitq_params *tx_params) > +{ [ ... ] > + /* beyond offload horizon? set overflow bit only */ > + if (ts > now + horizon) { > + tx_params->offload.desc_ts[2] = > + IDPF_TXD_FLOW_SCH_HORIZON_OVERFLOW_M; > + return; > + } > + > + ts >>= tx_q->ts_gran_pow2; [Severity: Medium] Can the advertised horizon exceed what the descriptor can encode? The hardware field is 23 bits of granularity units: drivers/net/ethernet/intel/idpf/idpf_lan_txrx.h: /* [23:23] Horizon Overflow bit, [22:0] timestamp */ u8 ts[3]; idpf_send_get_edt_caps_msg() checks time_horizon_ns only against U32_MAX and never cross-checks it against (1 << 23) << ilog2(tstamp_granularity_ns). For a control plane reporting tstamp_granularity_ns = 1 (passes both checks) with time_horizon_ns = 1000000000, the encodable window is only about 8.39 ms, but 1 s is published as netdev->max_pacing_offload_horizon and accepted by sch_fq and SO_TXTIME. Anything at or below the advertised horizon takes the non-overflow branch here and gets truncated: tx_params->offload.desc_ts[2] = ((ts >> 16) & 0x7f); so the departure time aliases back into the current window instead of being flagged as overflow. Would clamping help, e.g. max_horizon = min(time_horizon_ns, (1ULL << 23) << tstamp_granularity_pow2)? Separately, is the boundary test off by one even for self-consistent caps? With horizon == (1 << 23) << gran, a timestamp exactly at now + horizon passes the strict "ts > now + horizon" test, and after the shift it differs from the scaled value of now by exactly 2^23, which masks to the same 23-bit value, so the device would see "now" and release the packet a whole horizon early. Should the comparison be >= ? > + > + /* 0 is valid 23b timestamp, but also means field unset. > + * Increase by one to avoid this case > + */ > + if ((ts & 0x7fffff) == 0) { > + tx_params->offload.desc_ts[0] = 1; > + return; > + } > + > + tx_params->offload.desc_ts[0] = ts & 0xff; > + tx_params->offload.desc_ts[1] = (ts >> 8) & 0xff; > + tx_params->offload.desc_ts[2] = ((ts >> 16) & 0x7f); > +} > + [ ... ] > diff --git a/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c b/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c > index 1caf527069737..928de868fa624 100644 > --- a/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c > +++ b/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c [ ... ] > @@ -573,6 +575,54 @@ static int idpf_send_get_caps_msg(struct idpf_adapter *adapter) > return err; > } > [ ... ] > + memcpy(&caps, xn_params.recv_mem.iov_base, sizeof(caps)); > + horizon_ns = le64_to_cpu(caps.time_horizon_ns); > + gran_ns = le64_to_cpu(caps.tstamp_granularity_ns); > + if (horizon_ns > U32_MAX) { > + dev_warn(&adapter->pdev->dev, "EDT horizon exceeds U32\n"); > + err = -EINVAL; > + goto free_rx_buf; > + } > + if (!gran_ns || !is_power_of_2(gran_ns)) { > + dev_warn(&adapter->pdev->dev, "Invalid EDT granularity\n"); > + err = -EINVAL; > + goto free_rx_buf; > + } > + > + adapter->edt_caps.time_horizon_ns = horizon_ns; > + adapter->edt_caps.tstamp_granularity_pow2 = ilog2(gran_ns); [Severity: Low] Does this validate a different value than the one it then uses? gran_ns is a u64, but is_power_of_2() takes unsigned long: include/linux/log2.h: static __always_inline __attribute__((const)) bool is_power_of_2(unsigned long n) { return n - 1 < (n ^ (n - 1)); } IDPF has no "depends on 64BIT" in its Kconfig, so on 32-bit builds the upper 32 bits are dropped for the check while ilog2(gran_ns) takes the __ilog2_u64 path on the full value. A response of 0x100000001 truncates to 1, passes the check, and yields tstamp_granularity_pow2 = 32, which is copied into idpf_tx_queue.ts_gran_pow2 and used as the shift in idpf_tx_splitq_set_txtime(). The same truncation rejects a legitimate granularity of 2^32 on 32-bit. Would testing the u64 directly, e.g. gran_ns & (gran_ns - 1), plus an upper bound, be better here? > + > +free_rx_buf: > + libie_ctlq_release_rx_buf(&xn_params.recv_mem); > + > + return err; > +} > + [ ... ] > @@ -3085,6 +3135,14 @@ int idpf_vc_core_init(struct idpf_adapter *adapter) > } > } > > + memset(&adapter->edt_caps, 0, sizeof(adapter->edt_caps)); > + if (idpf_is_cap_ena(adapter, IDPF_OTHER_CAPS, VIRTCHNL2_CAP_EDT)) { > + err = idpf_send_get_edt_caps_msg(adapter); > + if (err) > + dev_err(&adapter->pdev->dev, > + "EDT init failed, err=%d\n", err); > + } > + [Severity: High] This is the other half of the PTP question above: EDT caps are fetched here gated only on VIRTCHNL2_CAP_EDT, and this runs before the idpf_ptp_init() call further down whose error is only logged. Should the EDT negotiation either be gated on VIRTCHNL2_CAP_PTP, or moved after idpf_ptp_init() so the caps can be zeroed when there is no usable PHC? > pci_sriov_set_totalvfs(adapter->pdev, idpf_get_max_vfs(adapter)); > num_max_vports = idpf_get_max_vports(adapter); > adapter->vports = kzalloc_objs(*adapter->vports, num_max_vports); -- Sashiko AI review · https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260910171131.2532487-1-willemdebruijn.kernel%40gmail.com