From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from smtp4.osuosl.org (smtp4.osuosl.org [140.211.166.137]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 3A527C4453A for ; Wed, 22 Jul 2026 18:35:33 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id CECDA40755; Wed, 22 Jul 2026 18:35:32 +0000 (UTC) X-Virus-Scanned: amavis at osuosl.org Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavis, port 10024) with ESMTP id TySL1fDbtxTy; Wed, 22 Jul 2026 18:35:32 +0000 (UTC) X-Comment: SPF check N/A for local connections - client-ip=140.211.166.142; helo=lists1.osuosl.org; envelope-from=intel-wired-lan-bounces@osuosl.org; receiver= DKIM-Filter: OpenDKIM Filter v2.11.0 smtp4.osuosl.org 012B44090B DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=osuosl.org; s=default; t=1784745332; bh=670ICVCxpkbIIsTKMOsa+I+z+C4FgJRDQNs6RF7SdGI=; h=Date:From:To:Cc:In-Reply-To:References:Subject:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From; b=W58U6x7j9c27mxkhZZsknjAqaEvYX0cvF+Gh1oqFOCUt39xZqJYOjCq8BpFzb6c1F jCBP2IS58/OozLgTjDAbWAtfWdvvQbBRaR8ZgLiBCMv8L4wrG99/l57wjl3PkbtCZo GUy4C5RRtjER/T5kHA5g/2L60ornB0FNrEtXiuvYWg+5BXzNWm7ThZT8mSpYkhe8d9 Kt5veU0IJjsvfd955+cZMH7iehDuABFBqEK/275lLRgUUwzYflPUTGIIVHZxMeU5c0 yq+nTmGdkpEaSbbNsIGxXoINOd5QOLVInD4Wf+tdmQQooWE/0q2o6eVVD8Z2cLT4cd whoEdXuZQ8SsQ== Received: from lists1.osuosl.org (lists1.osuosl.org [140.211.166.142]) by smtp4.osuosl.org (Postfix) with ESMTP id 012B44090B; Wed, 22 Jul 2026 18:35:32 +0000 (UTC) Received: from smtp2.osuosl.org (smtp2.osuosl.org [140.211.166.133]) by lists1.osuosl.org (Postfix) with ESMTP id 7DD35224 for ; Wed, 22 Jul 2026 18:35:30 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id 6352D40115 for ; Wed, 22 Jul 2026 18:35:30 +0000 (UTC) X-Virus-Scanned: amavis at osuosl.org Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavis, port 10024) with ESMTP id KnCInpVMko-z for ; Wed, 22 Jul 2026 18:35:29 +0000 (UTC) Received-SPF: Pass (mailfrom) identity=mailfrom; client-ip=2600:3c0a:e001:78e:0:1991:8:25; helo=sea.source.kernel.org; envelope-from=kuba@kernel.org; receiver= DMARC-Filter: OpenDMARC Filter v1.4.2 smtp2.osuosl.org 9F99B40057 DKIM-Filter: OpenDKIM Filter v2.11.0 smtp2.osuosl.org 9F99B40057 Received: from sea.source.kernel.org (sea.source.kernel.org [IPv6:2600:3c0a:e001:78e:0:1991:8:25]) by smtp2.osuosl.org (Postfix) with ESMTPS id 9F99B40057 for ; Wed, 22 Jul 2026 18:35:29 +0000 (UTC) Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id ABA7B43A5A; Wed, 22 Jul 2026 18:35:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2C4751F00A3A; Wed, 22 Jul 2026 18:35:26 +0000 (UTC) Date: Wed, 22 Jul 2026 11:35:25 -0700 From: Jakub Kicinski To: Stanislav Fomichev Cc: Lorenzo Bianconi , Donald Hunter , "David S. Miller" , Eric Dumazet , Paolo Abeni , Simon Horman , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , Stanislav Fomichev , Andrew Lunn , Tony Nguyen , Przemek Kitszel , Alexander Lobakin , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , KP Singh , Hao Luo , Jiri Olsa , Shuah Khan , Maciej Fijalkowski , Jonathan Corbet , Shuah Khan , Kumar Kartikeya Dwivedi , Emil Tsalapatis , Vladimir Vdovin , Jakub Sitnicki , netdev@vger.kernel.org, bpf@vger.kernel.org, intel-wired-lan@lists.osuosl.org, linux-kselftest@vger.kernel.org, linux-doc@vger.kernel.org Message-ID: <20260722113525.34092660@kernel.org> In-Reply-To: References: <20260715-bpf-xdp-meta-rxcksum-v5-0-623d5c0d0ab7@kernel.org> <20260715-bpf-xdp-meta-rxcksum-v5-8-623d5c0d0ab7@kernel.org> <20260721082728.74142e6c@kernel.org> <20260721183256.6f49d6e1@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Mailman-Original-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784745328; bh=670ICVCxpkbIIsTKMOsa+I+z+C4FgJRDQNs6RF7SdGI=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=a6LTxb6Me6mG2aUNvx62hRLaJopZgj2ogTsG8vH+9nTrF7phHbWJSmGpvev0Mxvvt 3c8U84ok5cF/v+rxZT6PsnyNEZnEti27oSLMZ9CjBWQ14jQOM+KjpEdYKOjUnyscea bD75r9/q7UDGNM7PAAcphCZ39vlipGyeAoYzQ+fLUEH8VNtac1NbFbz50FqsCzoChy yx4Eo3Q4/fyiLdyQPCRVfHlVSFX0DNSbXI2sqB0ToGN4AG0xOBFEB1dtrm4HHoicKc Z1YlaRTqCujzVsoH4VJYq92fziN8WHTbT/wc//wfZW0o1XGNXS+uwZmLenI7DcjKu+ iVpXtEUew6/mw== X-Mailman-Original-Authentication-Results: smtp2.osuosl.org; dmarc=pass (p=quarantine dis=none) header.from=kernel.org X-Mailman-Original-Authentication-Results: smtp2.osuosl.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=a6LTxb6M Subject: Re: [Intel-wired-lan] [PATCH bpf-next v5 8/8] selftests: net: add test for XDP_PASS skb checksum invalidation X-BeenThere: intel-wired-lan@osuosl.org X-Mailman-Version: 2.1.30 Precedence: list List-Id: Intel Wired Ethernet Linux Kernel Driver Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-wired-lan-bounces@osuosl.org Sender: "Intel-wired-lan" On Wed, 22 Jul 2026 11:00:07 -0700 Stanislav Fomichev wrote: > > > This is about current drivers that only report UNNECESSARY with xdp: the xdp > > > prog has to maintain in-packet checksum if it changes the payload. I think > > > it's a fair assumption? > > > > What about decap? If we decap the header that device validated > > as UNNECESSARY there's no possibility of maintaining the checksum > > (by which IIUC you mean correcting it in along the payload changes). > > > > I think we'd need some API to "decrement the csum level" ? > > Or some heuristic in the drivers to decrement if the head moved > > by at least len(IP+UDP) into the packet ? > > True :-/ I guess one more case to document? What would we be documenting? That it's a known bug and we have no idea how to address it? Or am I missing something? Again: .. the ask was to sketch out the plan of explicitly updating/invalidating the checksum even if we don't implement it today