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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 90E7AC61DBD for ; Wed, 26 Aug 2026 15:39:41 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6C72E6B0088; Wed, 26 Aug 2026 11:39:40 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 651676B008A; Wed, 26 Aug 2026 11:39:40 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4F2206B008C; Wed, 26 Aug 2026 11:39:40 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 21B226B0088 for ; Wed, 26 Aug 2026 11:39:40 -0400 (EDT) Received: from smtpin30.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 9EC0C12015C for ; Wed, 26 Aug 2026 15:39:39 +0000 (UTC) X-FDA: 85143830478.30.1C7B4DB Received: from CH4PR04CU002.outbound.protection.outlook.com (mail-northcentralusazon11013005.outbound.protection.outlook.com [40.107.201.5]) by imf16.hostedemail.com (Postfix) with ESMTP id C6D3F180003 for ; Wed, 26 Aug 2026 15:39:36 +0000 (UTC) Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b=dT3OoIBY; dmarc=pass (policy=reject) header.from=nvidia.com; arc=pass ("microsoft.com:s=arcselector10001:i=1"); spf=pass (imf16.hostedemail.com: domain of dtatulea@nvidia.com designates 40.107.201.5 as permitted sender) smtp.mailfrom=dtatulea@nvidia.com ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1787758776; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=jTQNsz/Wja0N/SSjuVRsEjik1ZGWR23+xu3Z38xgeZg=; b=VVS+iI8vBujTtXrbwRSToenLUZupvug+Qp+CLfd47o8V6uMgv+Jb38dBybMLA4DPJB7jok FdFMOe4KWlg58GGHn3hDm3Go88vIivdNvyxd2qBzHiHT73I3RFeqDOCRZvdr4FdssTJerT azT5JlQHBeWixm80ZP8lcoLcl6aGJws= ARC-Authentication-Results: i=2; imf16.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b=dT3OoIBY; dmarc=pass (policy=reject) header.from=nvidia.com; arc=pass ("microsoft.com:s=arcselector10001:i=1"); spf=pass (imf16.hostedemail.com: domain of dtatulea@nvidia.com designates 40.107.201.5 as permitted sender) smtp.mailfrom=dtatulea@nvidia.com ARC-Seal: i=2; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=pass; t=1787758776; b=7dN62ZcndKwklIJZ/Ugaxq62VyJ63mnSnNm1EAxpAHbHyJNiSfs+Nn+O+wJrczvNiLF09I Odu9geilFRXXR2+evZ4yCndOH7m8uLFfMKnQigpn16y2k7FQyyFEmuoNfuy+2aJaKynAAO Lk8LooIgHBEAxKi1en3gwSVAHD0EceA= ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=vooHsJbcObTzYef7DiLbNtN7e3WMwDXUGptaoxYqyPEcA/bZCt6xaEoKOVwVg1sXz6bPWbpBC40mKdWM72VRXxmQ+hTs/5Tx/0PjHpucPSiSmYZxVi02NRf8AekJydrbjpzcKeCbf4EgygGal3TKXHaSjELqvYpNsGOeaklwjK7z+FJc4Us649xo25SyxXOvq2GMuE5ccZkUPIDq8jdXNqXBLxICfKp6g18+qYo7xioX2kbm96QiuhL5VmmsNv9GWn/c1eM+CX4kYTjD+5SWMhAD15D7u22FTiCI00MeIzlgL6qqZ4dDbttBOS+9+ZpITghL9mY84zy0KS+fYYhtmA== 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=jTQNsz/Wja0N/SSjuVRsEjik1ZGWR23+xu3Z38xgeZg=; b=PqaKOwcq7gjwOxNzJWhlsrcLs+1u8oKwzWz7LKvdrkMH/geKwV5lxTzvc6w3Q5AC8CAWYNfkV6EjPHka73GGieUFgU3jAcBpVa4jJNpcMuMnfji3AsykFUufl9gjJdisAkwcLA3G/7gwltbOcK6NIchA34P20KTvjfTpyRve6ClY2NLHQbejcNXWrZdKWN4kKyAqW9fJ21uLP6snV0GXH6cwrAhyaixsErz8e2td63oWhXqoKVCXMteIKIaEDQ6TeqP0/HsovqFJh6PaHi2k6O7NPpuGYC5xzEqOiaw1e/wg1sf2NjuwIKvYkwpVpG6DY3GG17Yq474qaYBdiWB9AA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=jTQNsz/Wja0N/SSjuVRsEjik1ZGWR23+xu3Z38xgeZg=; b=dT3OoIBY4qSceOy5aspmvGdOclKHH/v1hpazCguXSEjyg1SfMrW7VarMXLxAeN5dZEOPKHyCgApvLFnFUtq9f9YHQn+Cgq0P+y9HTIKTGhqP8B91N+mrW37xzID5mELKN3ZOALB0t5d7e7dKt23KnE7l9iDWX4N/Zxszh0HzCE5AFmXWjONy8TpWwKcPxyBPfRXbNEhnL9kA/zJJvNYJciB/9wti/xBFIkwYEI+1R2f6UPYQkfmtIU2I9r4iywn1eyVzAM39LdePS/1efHg0pBSFlaJxwbq1P6CQmNCJhhEsMYqAqZ1jryDRMNLdN88UGNuJCZog4uKNtH0+DdZCpg== Received: from IA0PR12MB8716.namprd12.prod.outlook.com (2603:10b6:208:485::18) by DS0PR12MB9397.namprd12.prod.outlook.com (2603:10b6:8:1bd::15) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.360.7; Wed, 26 Aug 2026 15:39:26 +0000 Received: from IA0PR12MB8716.namprd12.prod.outlook.com ([fe80::c18d:8eab:b36c:32da]) by IA0PR12MB8716.namprd12.prod.outlook.com ([fe80::c18d:8eab:b36c:32da%5]) with mapi id 15.21.0360.006; Wed, 26 Aug 2026 15:39:25 +0000 Message-ID: Date: Wed, 26 Aug 2026 17:39:19 +0200 User-Agent: Mozilla Thunderbird Beta Subject: Re: [PATCH] swiotlb: avoid double copy with swiotlb on tx socket To: Mostafa Saleh Cc: Luigi Rizzo , Jakub Kicinski , rizzo.unipi@gmail.com, m.szyprowski@samsung.com, robin.murphy@arm.com, willemb@google.com, kuniyu@google.com, davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, gregkh@linuxfoundation.org, rafael@kernel.org, akpm@linux-foundation.org, david@kernel.org, netdev@vger.kernel.org, linux-mm@kvack.org, iommu@lists.linux.dev, driver-core@lists.linux.dev, linux-kernel@vger.kernel.org References: <20260615234220.3946885-1-lrizzo@google.com> <20260615172535.080cf94f@kernel.org> Content-Language: en-US From: Dragos Tatulea In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-ClientProxiedBy: FR0P281CA0253.DEUP281.PROD.OUTLOOK.COM (2603:10a6:d10:af::8) To IA0PR12MB8716.namprd12.prod.outlook.com (2603:10b6:208:485::18) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: IA0PR12MB8716:EE_|DS0PR12MB9397:EE_ X-MS-Office365-Filtering-Correlation-Id: bf00e31b-298c-4d1a-b0d4-08df03883529 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|23010399003|366016|376014|7416014|10067099003|4143699003|11063799006|56012099006|22082099003|18002099003; X-Microsoft-Antispam-Message-Info: 2vAiH9WlRO/QIBul3BUcqHMZES9GIAnu5CuEucmtauX65B6UkH78owbxkD4uqnVCpNd11UmwZwg7j3FWCSem8IGsWCi8qS2BqJX83fhLqfTA8zvRDaBCHxR8/eQKL8Th40S6Fkdq8MCVObdLYgmvr5H5v2HkDKOzia5fTCHy9NY91qnX6eN+/e5ypajA4+e0wFOmfTiSRef03BEa++Biws41HtWWBYcVsU6P1/2rGVJF0Rk1svs2f6YFiAxBAttGU0VY98CFQAsfjFGdoy0OCt4x2x6D8olAEA9Or5t3zt6hvGSHDVywwk2nVD62Fedr84VLlqGVYoZZE8N2LEgwWw4P20B5mJp84HHpVIOCVREVrmZIQ+uOe2QbIjFfTLjpCdYw1c8CQk/linozjlyEL1ArU34Yj/OJU8BQ0PaGHzbIbLDhLiCtVe7x8v/ZyryW4peHm/wdNn61o+Efz4s/rvKKRQ2TuDKyNMCg2YVvGtJd1QX8HDd1rxzafcCpHeRz+KjqJHMTbqFbuSDY6RO7U/Wgvs9rfw2cyUggV293yc1Sy3Y1A1k2V2umFyDTtejl2F7Yvmp75f23mL/8mGKpT9v2BWyLUvv3RUQS5y9LLMU8pPMDgpmwWq5keggkX+d1vBaZltTdPDagpWqsr6K37g== X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:IA0PR12MB8716.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(23010399003)(366016)(376014)(7416014)(10067099003)(4143699003)(11063799006)(56012099006)(22082099003)(18002099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?b3hlTnNKbjVSc3FtYmkxbGZRMHJoeTVSZzZjb3RMaUc5MEdoc3NzbUVndDRr?= =?utf-8?B?U2lmRlc2MGMzRDVSc0lwb1FRditRMDM4WFQ1UkhrVlpsOWdkNDJBZmEyajNU?= =?utf-8?B?T0dHL0lVd2RKMGxjN3B6eDdLWmpkVUdyNFpGTmtaNTZwQUZxWndpWUIrRkxD?= =?utf-8?B?dFZ0Wi9Tak5RR1gwRzIwbnNVUlo1S05HenJYWDEzem0waUNrR0hTMStIejJV?= =?utf-8?B?MHVab2ZGbnpKRFQxQ0FDMlh5cXozMFpPbGpLSHFVY2NNa1hhTjZRaGR1bTJv?= =?utf-8?B?Rjc5emF1dHNaV0diYVBvYkc5cVBqVHpjcDJNSlJ6RXJ3SjBmRUtXKzA5SkpT?= =?utf-8?B?cEkvQldJVmxwQ2VabFFWbWpMYXlxRjJScm9ZdTI4Vkl2RExMU1Y2ZmdoczYy?= =?utf-8?B?akcvV3VhYjU5cXFVOGxRWnNtVGZiN1BpRmt2NUpGYmNSQ1UzTFRJeVRJR1oy?= =?utf-8?B?N2ZkZHR0bnN2Y05JcmMyUDYwQWtJaFZCYzlBMFpzSHNDTkk3V2w3ZUhDTldy?= =?utf-8?B?K1NSTmJjcmIwOGE4bnIyWDJrYlZjQXdraVhEVk0xWUlnV1Y0TWZwTmtIRGFK?= =?utf-8?B?ZXFLS1FsaVNETTFJVjF0WGtVdUoyaUgvYTlIdSs4c0p4eEV5YThkTjFZMExM?= =?utf-8?B?T1FhZUhSMDJ4Wlg0cmlVZ200cFNqK2NXVU0rNmpwRGgrMUlqLzRyRm5Xb3pz?= =?utf-8?B?d1E0QjF4bWpFMFo1MkMzenpiVS96V3l4cHhiVnBwTG0zQnJuV3BOMUFRdS83?= =?utf-8?B?NUtwRVhESHB2L05PNW45b2VVRnhCODdwK0Y3Y3BoRFlqb0M0OW5TUzRXdFVP?= =?utf-8?B?MnZEc2ZOQ1QxUTdMREVhVVhoVDdJT1QxdTZUZytRR2FIdi80YytDRElGdkFY?= =?utf-8?B?QVBjWm8rZEx2NjRPVXgvcElLUUFjTEhlNHJhYUxyNm5LUHE2aFVNL1ppT0pW?= =?utf-8?B?YWRWcERhcnpUbXloZDFUVG9UV2hjRUU3MXNjTjBZUTJMaitlL2Nabnc2cjZQ?= =?utf-8?B?TVN2UmlPQm5nclpNNHVTWHlnelNOTnQ2SDQ2UnZWWjJTdWxHYWVzamhyN1A0?= =?utf-8?B?MDVmK2FJWDJVUU1EOS9Cc2FHa3pxZGlMWkl4Y0twNlBlMXVzdUR6MzAzdVd6?= =?utf-8?B?Y2dOUG0yY0IrZmlNdzUvZXFSRU1oSDhQUlN4UzFNYzkxRmdmang0MVZxMTdW?= =?utf-8?B?Z0JYNTJvZTB6UTlZczZIOWo2WlN0YjlZUEJuNnF3b21CWEtZbXBJMUxFQ2RX?= =?utf-8?B?YTQ2eTlmdFRCRE1nakNwMUltV1lkK1NBandKRVVaZWt5SWxZOUE4d1FCc1RI?= =?utf-8?B?UlljblZRUlR3UngwUnhQSm5PeXcvSmhmV1l4VGxPSnhvMlJEMjMydTB2ckFl?= =?utf-8?B?MmM4MzN4QUl4clpxREs4amwxUXhnY0RrRW1QeDVRcThPdDYyelhPakk2VVps?= =?utf-8?B?bzVmTHNndUVJVThFN25VbktYWXZqR2dWUk1QUm4xaEZuWkhvRkQyL0ZtdWZK?= =?utf-8?B?S0dUcnZISEFSczJMTFpuMzBJbVRCdWtRQ0FYbFF3OUE2d2FDdXpuQ3RiMGhY?= =?utf-8?B?SU0wTkw3V1lYRXdhVW5hOXBDcGlEZjV0MmlVT0V4N3FheWc1NzhpbWtPclYr?= =?utf-8?B?MnZCOHhONGRQckk4ZG5WcWw5SElvQ1Z0ZitQU3VxZnFOTHZXUnNacnhIbmpW?= =?utf-8?B?WkR2M3lIbktwZ056MVRCcEYyeFl1WVNXQlhZQTFTaXNFcVFwNEg1ck96Z1BM?= =?utf-8?B?K3B1SDdpL3RCNDdSWnV5cisvK3lMbGc5alE0K3l2Nis0Y1NiZlhrK0VWWTB6?= =?utf-8?B?S25VUzlkdG4zRW9zSDUzb1hoTk1mUjE0TjJaRUNnb1dqWlJDSmg2cGNYWS9z?= =?utf-8?B?R3J0RzlTVWltZXdtQ3ZWUHB2WVNUbjdCdWJ4RElFMFB6RVN0bXFxYXB3bnky?= =?utf-8?B?RzNzbmcwRE9aQVl3d1ZXazNIeE1LZlJmdzQ4WDVCeDNTaStTSUIvK1ZxY3Iv?= =?utf-8?B?SERmQkdmK0EvK2MwZzdwbyttNU1kWWZQdUg3ZGVzTWtINnM3NElKVXU5dklU?= =?utf-8?B?R0d6Y1dqTklIdjYxa3NwNitFVzBmMGRDUWlpTUp1a3FpcEM1MWFGbVZnSGpm?= =?utf-8?B?NEFSeDFDK2E3djgzTlBoVG5UcFRIUVdsaWZhRmZ4bW9UQjV5Z1FaNHhOY1hE?= =?utf-8?B?V0cvL0RaU3RDSUIxcTlrLzhCNEdHZXhOeE9TVVFoNWF4NXBVMjNTOTFVWEwx?= =?utf-8?B?d0Y1YW5SbVNDSFNSK2pMWHFRU1R5RW55eW1vdWdxcktzV094RUY3Qlp0aTgw?= =?utf-8?B?OU5NV04rNXBCOWVrUXB0MVBOM3RSZWJOK0pBdFpvakRCZ3RwUHltQT09?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: bf00e31b-298c-4d1a-b0d4-08df03883529 X-MS-Exchange-CrossTenant-AuthSource: IA0PR12MB8716.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 26 Aug 2026 15:39:25.5086 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: yuDZUJk0MEl+6MBRg4iCoqaHhSrRVYpKiAG+vx0jSkSZCPqj0pjWNbVAt8ZegjmN2A9nzwSR1XhZHWdwktlQOg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS0PR12MB9397 X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: C6D3F180003 X-Stat-Signature: p4nz67un8tc3wtre1kx94jketr5npg43 X-Rspam-User: X-HE-Tag: 1787758776-26622 X-HE-Meta: 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 biVtlqJ6 3K1a8ZALK88Z4KiKLABx2cft/9wx94w/NQDmvTPkDfqJGqOF2nhrlUYKqChq/8iYJtXULDZ6cx62bqZOPR3sUGnYrRHac+V7JX5zUueTEicPKCnn1J/daESB2hYNMcZhpMUisCoD4r/0IwnYmBpRJo2Mt/tqs8iT1VvNEV5FMU6H3zos68vwpV6RqGKriUhoGFNq8LV0VegXkqB0wcKC1NtR7Ez5wuQCMj492Rn9woKCkO2QBmrWGRDdSubQdMbrEexVR76Ns+R3V44bETa0RWPVlFysgDvybhobka7IaTH3zXmQhm+OHSggAv5XVNJ+ems1knHTMhG0gv7aYf8txGHU94kpgZ1u2Lfs4JriQobD2GLQQswydR0Hl7a2zmuwSytkBJ+Xnx4dU6Y3Py6qpRMNB/0g00zK68FL6hT58hAmVh7PlwgZCpMAJwpo7dM+XmYDB5USx2QPYd0c4cewSgFfw+r5XzATpzQZW8PauLFeDCm0= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 25.08.26 18:33, Mostafa Saleh wrote: > On Mon, Aug 24, 2026 at 10:59:21AM +0200, Dragos Tatulea wrote: >> >> >> On 16.06.26 13:06, Mostafa Saleh wrote: >>> On Tue, Jun 16, 2026 at 02:33:52AM +0200, Luigi Rizzo wrote: >>> [...] >>> I am still looking into this, I was planning to bring this up in the >>> upcoming LPC. >>> I will give this patch a try. However, I believe that we need a more >>> generalised concept for CoCo pre-decrypted allocators in the kernel. >>> >> There is a talk at LPC in the networking track about this [2]. This is >> exactly the type of discussion that I was hoping to have there. > > I see, thanks for point that. I plan to be in LPC, so I will aim to > attend this talk. > Great! >> >> Besides the issues mentioned in this thread we've also found that a lot >> of overhead can come only from swiotlb allocations when running many queues. >> >> I will add information about this series in my talk. Hopefully I will also >> have time to add some numbers for comparison. > > I had a quick look, I am not sure how that will shape at the end, but I > think we need a general solution beyond NICs. For example in pKVM the > bouncing is used with virtio devices, so doing this per-driver won't > really work and is not possible in some scenarios where memory is > allocated from the core kernel and then passed to the driver. > So, I was thinking the kernel relying on > CC_ATTR_MEM_ENCRYPT/force_dma_unencrypted() could detect that and > allocate pre-shared memory for those cases. > Ideally it shouldn't be per driver. But I was thinking that there should be a way for the user to provision memory for certain devices. Thanks, Dragos