From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.18]) (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 7C3AAF507; Tue, 5 May 2026 00:10:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=192.198.163.18 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777939840; cv=fail; b=AcewzGZFP/X5+IqzoU2oR0/fmOaPkxbm7StnlSYjdB+Un6IjVBYwZOlsJwFEwh+yKCE5lpyqmMP53m8LG+WWgB+4rB+6hZsuAGFLoHgq8d74DBAnKS0pf9uAQt4n/CcTUXJDq9uQrU0D8Mte9prgD/Tt7sVNn2b5nBAbMhHuYP4= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777939840; c=relaxed/simple; bh=bpiVw8jiuuRE8wstR97zsk7ygmQKSCrrYadSc/lPbfU=; h=Message-ID:Date:Subject:To:CC:References:From:In-Reply-To: Content-Type:MIME-Version; b=jOuLfMcnDiNogOF918bvBcYbJo3/l31YWePJHFx2DAt3vOmseRO2aRKAQTabpvXEn3DjYpAXTGq5l62XGuCxRD12ry4yzJfk/PxlCTd/87e6Gu/ieLQuJwGpPE3Y3e9d/L4Lc9urkWCZOaBmNIGE6fXwMxaLXRrtqDIuRCJGJDw= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=RCueqCHH; arc=fail smtp.client-ip=192.198.163.18 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="RCueqCHH" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1777939838; x=1809475838; h=message-id:date:subject:to:cc:references:from: in-reply-to:content-transfer-encoding:mime-version; bh=bpiVw8jiuuRE8wstR97zsk7ygmQKSCrrYadSc/lPbfU=; b=RCueqCHHBdcQwAOWafuuHJwTjzXRJTeuugmTXiGCYCKx1Oi4KZ4OvHan 03crbYvrqg2p1cqzwYF9WZHVX7iJqJSke3DdIsY6kJhzXnJXyXkj21j0q 7qLxN0aHIa3rIiO8ztOp7PmB0OJOepya+Z5PiKbcJ1MEpxJFMF4m7xGf5 /zIdKN6eGLSeDdgzuJOWC6I1wi+FoFiQYYJ8Pkk2elVXOwC8PYD9jUCdI 9Z7wYWZ6DWl54LOdS2JIiSQez2aleBu+tWr+uPHUS62y3dachrCZ15nW2 fzDd5yGfCKyH87roM44GsAT+qdiIN9+BHGVjQZTb3CxFC4JCoi/MwlkEU w==; X-CSE-ConnectionGUID: gUKC37P9RIO2GP8lrZAmsA== X-CSE-MsgGUID: kNP6YPnlRbWvO4c+LKmBEQ== X-IronPort-AV: E=McAfee;i="6800,10657,11776"; a="77962022" X-IronPort-AV: E=Sophos;i="6.23,216,1770624000"; d="scan'208";a="77962022" Received: from orviesa009.jf.intel.com ([10.64.159.149]) by fmvoesa112.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 May 2026 17:10:36 -0700 X-CSE-ConnectionGUID: MLYlAzPrQkOgG1awnHLjow== X-CSE-MsgGUID: aJ6ZMcD5R7GdytCzB62nLQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,216,1770624000"; d="scan'208";a="235711126" Received: from fmsmsx903.amr.corp.intel.com ([10.18.126.92]) by orviesa009.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 May 2026 17:10:36 -0700 Received: from FMSMSX902.amr.corp.intel.com (10.18.126.91) by fmsmsx903.amr.corp.intel.com (10.18.126.92) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.37; Mon, 4 May 2026 17:10:35 -0700 Received: from fmsedg902.ED.cps.intel.com (10.1.192.144) by FMSMSX902.amr.corp.intel.com (10.18.126.91) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.37 via Frontend Transport; Mon, 4 May 2026 17:10:35 -0700 Received: from PH0PR06CU001.outbound.protection.outlook.com (40.107.208.6) by edgegateway.intel.com (192.55.55.82) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.37; Mon, 4 May 2026 17:10:35 -0700 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=aWITGwHTl5wRsNtsaH5H4ZMlguKMCHvx3k3+i4qzcJF1kD7vNcagUAsFOuXg+H9LANuxYDH/DoJq0XQClma6rkj0ZOvCjqP3HExISkc1OZ7lMhLW59AbfUNQWSDA3aJ25q5PWH8V6cDt2fvLm0Ykvy05jBmWOHSaiXP6mWN6b8KkvlfR7BlubD481oXBNWpfcMRdfjD+vAX9U8NKB0Rr39SgMH70vWgRjdYa80hfz1XDw7R/s/4jVoni7FsyYhI6gmnHYFIzw5e7XdzBggja9ZtMH/l0nIqa+COKbXXWuNNe30SLq3lmrlQHdmB7LwwOkjVzWhnT85NYYBeEyB0Ekg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=suUPEEa/Hl9vIo4bmtAyw/8k75zSd3pplEfbIdFam0I=; b=WK2B5bi6BiAzsTeVdwyBR/defOhpl7I0J8EAy7Dxeztp8CCFaMTkWUsSMH6HNExrO1kPTSRJmEs1FvdBBTpRLRnMabbGxvpUsujlCmMPj+tFGbcnSDT7UDjZHP2W+Wh539KlqbuCqLYUaZ/LKlaHVa/5DQdb1P3w2ZtGHDRSPMfmDKke1AC8h/ZQmWOZ+tvJTReEBEq9STKADOWOYQpB6rXlSw42pJIlBt4VsmLjeQyQyv0mpCFIy6d7R+kexprTYAMIiPv6QUCU1oKFfzZRsWWbSJr+YA/3GDFuoDVvDBdmKlDT4DHTNtkjpipqNnPGAlZ4F/cbBmV7+3Xv7SnecA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=intel.com; dmarc=pass action=none header.from=intel.com; dkim=pass header.d=intel.com; arc=none Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=intel.com; Received: from SN7PR11MB7592.namprd11.prod.outlook.com (2603:10b6:806:343::16) by MN0PR11MB6278.namprd11.prod.outlook.com (2603:10b6:208:3c2::8) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9870.25; Tue, 5 May 2026 00:10:32 +0000 Received: from SN7PR11MB7592.namprd11.prod.outlook.com ([fe80::3e09:8700:df72:37b6]) by SN7PR11MB7592.namprd11.prod.outlook.com ([fe80::3e09:8700:df72:37b6%6]) with mapi id 15.20.9870.022; Tue, 5 May 2026 00:10:31 +0000 Message-ID: <531aec13-c33f-4e77-ab48-de8861f9b6c6@intel.com> Date: Mon, 4 May 2026 17:10:23 -0700 User-Agent: Mozilla Thunderbird Subject: Re: [Intel-wired-lan] [PATCH net v2] ice: Fix missing 1's complement negation in GCS raw checksum To: Matt Fleming , Tony Nguyen CC: Aleksandr Loktionov , , Matt Fleming , , Simon Horman , Przemek Kitszel , Andrew Lunn , "David S. Miller" , Eric Dumazet , "Jakub Kicinski" , Paolo Abeni , Eric Joyner , Paul Greenwalt , "Alice Michael" , , , References: <20260501095717.1032151-1-matt@readmodwrite.com> Content-Language: en-US From: Jacob Keller In-Reply-To: <20260501095717.1032151-1-matt@readmodwrite.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: MW4PR03CA0330.namprd03.prod.outlook.com (2603:10b6:303:dd::35) To SN7PR11MB7592.namprd11.prod.outlook.com (2603:10b6:806:343::16) Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: SN7PR11MB7592:EE_|MN0PR11MB6278:EE_ X-MS-Office365-Filtering-Correlation-Id: e7f7db99-f637-44a0-39eb-08deaa3ab8a5 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|1800799024|7416014|376014|18002099003|22082099003|56012099003; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:SN7PR11MB7592.namprd11.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(366016)(1800799024)(7416014)(376014)(18002099003)(22082099003)(56012099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?dzVreC9laVpPV09xQlpVMUJjQkNmM2o3YzdhbTh1SFFDZUFLeFVKcXdycDlR?= =?utf-8?B?aFhET2dwNDFBek55NU1RTGpWay9PSU5kSTVla3lSU0F4SGtoRWI4eUhPUzZZ?= =?utf-8?B?V3ptcHhhN1lrS2pjWE1JUm9NRGplZzFIRkNkVDVmVjQyVzVjZFVVTEZTb3hy?= =?utf-8?B?cUVUbmZlZkI3eW1XRk5yQzJFV0g5ZmdQNlhxZ3pyN3ZFYzhscU42SkYxUFRR?= =?utf-8?B?ZTN5UWpKOHVQcjZITnZybER4a09NM1UybWMxbnFGYksvQXIweStxellMemFM?= =?utf-8?B?cWNGc0YzMTA3cTNEeE55elFIVVdOME1Edm9RYk9zcnJJR0xOcGF5T0xVcmUr?= =?utf-8?B?MEJtd2VZcXZtUWZJN0dZWGJMVDJPSENTQlhnUk5vTDA1OXZhSjROd1J1ak8y?= =?utf-8?B?MEF3ZmZaZzBjQWpMbU5YTWVNWWpISjlsM1Z5YjZ0cVhVL1E2anc1MkxxYllE?= =?utf-8?B?djhlU3hWalZDdjdBQnM0b2FobXpWd0RmMUtmcjRkY1o1WDFjdGd0aFlQYmJV?= =?utf-8?B?a2tWWXM4UVZrVEM2SFNWdjc1UnZUWUhyeWh6anhwbHAwbGdJbGwzMThuTSs2?= =?utf-8?B?NGMvdUlFNzF0UG9XMFhyK09BMXVPOXhOeGZnb1IwNHJyY3NpeWoveVpSMnNL?= =?utf-8?B?MkhPbTM2RlRHQlFUVGtlSkFXZmpXOElDWUthQ0VWc0NRd3BCVnk2TFR3THd2?= =?utf-8?B?dUlpeVZBNmhVUWFOVDA4SEpjRXRtcmVrelIzN2NydnZVYTJkYkJ4TFdKUUhM?= =?utf-8?B?UGI3alBCT2VQb1RWOUFVK0FOV2FoSFRvbVVWQURvcnhJS2JlK1ZLYVc4MU00?= =?utf-8?B?Z1l3MDkxenR2VmxUanFaeUIyTjlETHZtb2J2WnBtVU1va28wcGpCVElnNTAx?= =?utf-8?B?NTVub0NsRTZDM2NubnRtS2dtYTJESWtuQnVFSXo5YTV5MzVTN3JvQmMzWEJq?= =?utf-8?B?UDdoeXN0Z3RoOXg1ME04STRxZlBRMlFMTHZzdktmVVdCRnZ2K0dMQ09Ib3Fu?= =?utf-8?B?aS94ZVhyV3d1YXZpb2s0YnNOMFRtT2RTcFpqb3dyaEYzOGNjMGJXRVNWNnlh?= =?utf-8?B?UDRHS0QrTC9PclgwaFJheU5uVkZwY0JNZmVHYVFjd1RxSVp3dCtrcWVHYWtJ?= =?utf-8?B?THZwSXROblptc2pZWUJEcGJtUDltV0psaUtOUVVtQmc4QTc4UnRXb2FpRUJ3?= =?utf-8?B?RURFZXZMd3VlYk9Cck91Tk94cWdpb09VUHJ2SmpVaFdKK1VobjBDTm1udmZH?= =?utf-8?B?ZjhiWGo4cnA2MC93ZnlMZGk2SktFd1pvMzZQWGdaYVl2QkQ2OEF0QjEvRHFR?= =?utf-8?B?VVpyaTU3QkVmeFl1YUV5SEVRZ2ZLREdPMUFPVXYvaFdZeFVwcjI0WGF2SnZV?= =?utf-8?B?c3dWNzJnY2phcElTNkVtdFB6L0lkVVIzNXkvOUNNNUhhQXdDci93SXRleElR?= =?utf-8?B?VXhjbTErelVrb0RkVUlvdW9GdDRvQW94QlZNTUZ5N2NtL0ZnTHIvVW5JcEVx?= =?utf-8?B?Um53U0RFRGc1anhLUCtjSTJQZjROd1FJMWUxamliMVZvNWo0bENaeGxVRG9J?= =?utf-8?B?NEh0QjlDU002NExHd2p3bmpCSHdzRmVPK0ttVVdSRkdoZ1FHZXVxejU2cjBz?= =?utf-8?B?ZW10bVRCeENWaDBXREFTa2E1RFNmdXNwZEY5TE5Uc0JkcHU3NmFuNHprRVh1?= =?utf-8?B?QzFaRkt1NjMvaDJ4VHpPc1RPdFg4VnFRVkFIdW1jdXhHZk5BOE1yTGVRcFRj?= =?utf-8?B?elIyVWlERVRDTzk5Z0VkN0RnREhEYXRjeHMwSXRCVHQzU0QzSHk3d0V6STZ2?= =?utf-8?B?RVltL0lwbGFlb21KY0JQY3ppOGplSTNXTk55NERwOVUrWHUvMmpGZkRQRmlP?= =?utf-8?B?OFNzWUYxUlMwS045OUwwMitxTi94RUoxZHVONTRPT1dWNzR6S2RqbHhpSHdi?= =?utf-8?B?QXZOVTJOS3EvUThtdFl5WE1rczRxYW1RVTd2NnAySGQvSXUwK1gwSHh6OHIx?= =?utf-8?B?NS8vdEU0RXZBRjBORFRaMElPYTBUMDVkNE5jMVpaMm1rZ1k2MCs1clcrOTR4?= =?utf-8?B?dCtPM1JyMGZ1N1M4NkZ3ellCaDRpdjJFR0pNd1lvUTBpNVZmSGlXVEdpMTNp?= =?utf-8?B?cVhzNEVWTCsrYk8yMzB4WkpHZVlaWENEaElqVE52QTFUemlKeWNqTndNekU1?= =?utf-8?B?VE9OdGduZVlCK1NZaUZCZ1JQcHhtMjU3OTh5eGw2ckNOclVsYUFsbTcxSDRW?= =?utf-8?B?V0ZQeVZ0VUlzcDhLak5TWHk3VDNyNitXa210NmZqWUZ4UnZ6TnVGNDdEODNP?= =?utf-8?B?WVZqOTRQekY0ODNpRys3MUdXeGgvczNwZ0NDaDBvbE9VVVUxNU1TUT09?= X-Exchange-RoutingPolicyChecked: r92H26LBX+trAaH2Kx8sf0YIadApCsBAxUSdMlOHUntSXyxdwRvK6PtAUp1iFrOeRWrtimysBwVGnhGNMsWNmCwzNd1dlV1a6j+r6RFWklAxiftDfYe+RCwUnnr6Hpb9tl2NwX7rgfI0Me5ldHSHjXXKqDYS76PxIvW7xQ3th7aGiRWZsi9T/w5m8c9UAclmZ33ZvTZ6aO1XozxB3AXYKizu6BC+eI3PHw1f0WBtvoNKBIvPhOyNem8KiIBI6W3ZdZBuD+ujXsEMoRXtmIMF3qURvJW2DeRD2aYs+5a58BoCRKgthlO1/kTWvTYh/fNhEQmQ4lPNenmwaxwBHhbZxQ== X-MS-Exchange-CrossTenant-Network-Message-Id: e7f7db99-f637-44a0-39eb-08deaa3ab8a5 X-MS-Exchange-CrossTenant-AuthSource: SN7PR11MB7592.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 05 May 2026 00:10:31.7835 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: MRcPCa6og1ntgs31T1JSs5x4wxWr/SaXvH63N8GxSFayzCuVeVQ0jUA7m4Kg2QjJ+4NyrcQz+TqkDkiueRNuP/lyvKa3KhuHbwZigXshoaE= X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN0PR11MB6278 X-OriginatorOrg: intel.com On 5/1/2026 2:57 AM, Matt Fleming wrote: > From: Matt Fleming > > Commit 905d1a220e8d ("ice: Add E830 checksum offload support") added > Generic Checksum (GCS) support for E830 NICs but omitted the 1's > complement negation (~) when converting the hardware raw_csum to > skb->csum for CHECKSUM_COMPLETE. > > Without the negation, every CHECKSUM_COMPLETE packet fails the > fast-path validation in nf_ip_checksum() and falls through to software > checksumming via __skb_checksum_complete(), which triggers the > rate-limited "hw csum failure" warning. Packets are still accepted > (the software recheck passes) but hardware checksum offload is > effectively disabled and the warning floods dmesg on systems running > nf_conntrack on VLAN sub-interfaces. > > Multiple other drivers (idpf, ehea, iwlwifi, cassini, sunhme, enetc) > also apply ~ for CHECKSUM_COMPLETE. The ice driver was the only in-tree > user of csum_unfold() for CHECKSUM_COMPLETE that omitted it. > Hi, Based on your patch description, I assume that you've tested this on real hardware. I dug a little through some of our internal changes history and sawe that it looks like the hardware has a register setting in its GL_RDPU_CNTRL register which determines whether the checksum value reported is inverted or not. In E830 hardware, it is supposed to be off (i.e. the checksum value reported already matches the expected setting. Perhaps your device somehow got the GL_RDPU_CNTRL register set to the wrong mode and that results in the swap being necessary. Hmm. I'll ask the team to see if they can confirm this behavior. Thanks, Jake > Fixes: 905d1a220e8d ("ice: Add E830 checksum offload support") > Cc: stable@vger.kernel.org > Reviewed-by: Aleksandr Loktionov > Reviewed-by: Simon Horman > Signed-off-by: Matt Fleming > --- > v2: > - Add Cc: stable@vger.kernel.org (Aleksandr) > - Pick up Reviewed-by tags from Aleksandr and Simon > - No code changes > v1: https://lore.kernel.org/netdev/20260408190214.1287708-1-matt@readmodwrite.com/ > > drivers/net/ethernet/intel/ice/ice_txrx_lib.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/intel/ice/ice_txrx_lib.c b/drivers/net/ethernet/intel/ice/ice_txrx_lib.c > index e695a664e53d..c177579e0114 100644 > --- a/drivers/net/ethernet/intel/ice/ice_txrx_lib.c > +++ b/drivers/net/ethernet/intel/ice/ice_txrx_lib.c > @@ -92,7 +92,7 @@ static void ice_rx_gcs(struct sk_buff *skb, > desc = (struct ice_32b_rx_flex_desc_nic *)rx_desc; > skb->ip_summed = CHECKSUM_COMPLETE; > csum = (__force u16)desc->raw_csum; > - skb->csum = csum_unfold((__force __sum16)swab16(csum)); > + skb->csum = csum_unfold((__force __sum16)~swab16(csum)); > } > > /**