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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 94E52C33CAA for ; Tue, 21 Jan 2020 14:05:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6242F21569 for ; Tue, 21 Jan 2020 14:05:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=Mellanox.com header.i=@Mellanox.com header.b="ZrZdHQnk" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729073AbgAUOFK (ORCPT ); Tue, 21 Jan 2020 09:05:10 -0500 Received: from mail-eopbgr10075.outbound.protection.outlook.com ([40.107.1.75]:8174 "EHLO EUR02-HE1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727817AbgAUOFK (ORCPT ); Tue, 21 Jan 2020 09:05:10 -0500 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=ghChAIvnTjU72aZ8uN7llJtLVkWPnUZ5PzMLsuKaj9QrPd+xMqlMzIlYF6VS1I29FMfJwOkq57Q/jhvmSfhg+cUctyesYtIL/lfyPFzGR/pMs3dPEMtWyd5878WNv9E1od1nVGtLRF5rbphnGnpj/zz+u1m+V5I1TEV2k5ztN8MAcFr6IG6rcjW3jLOv0ID537t4G8+xxhS4mbe1QAYTyBPkUOn9xhiJba+vpIkErNpSAxUIG2/73ELbMdE0mJUhjdKXvzhdpOwfA7/+cLz8koZx2OENb3L4QlRiBnFiHrYJh/uR2DEsJtsoACTJppGWuVRjHjg2XatBhlDw7HBLIg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=/7OzItzkaEvJ7h4xt015A/r1HsxEaQKVQAX2j+LjPfU=; b=lmNHsCn5c+KQ3Bnxyp6jEF280T3dEuQXHYON+XRk/lEJY1Mqejm0ydEbE9V2T6lCdJqmWLpI/coRPihJD40dFz5y/JbdJ1idkMeL/wvuf5O6kYXXUZogIOIsvqgrqZeAQ2HF8FhOraxk587/64XlLLfHa5C3JgPAnVfKHYUvboml9e718nOHjBEuTbxsQlJAyiDTOuVFBDO58Xvdt73SvP089ZvhYLDAMlEME70uwMsi4QomkbMfAK8OpC1glruKm8Y6qTU0zFMtyJf/d1UrbeQl62F1dDWcyt3aNu4bRKrAa8tGaHbcgX0RvO+kSO1/IZYY6KhTQy54Rq9JjhGszQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=mellanox.com; dmarc=pass action=none header.from=mellanox.com; dkim=pass header.d=mellanox.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Mellanox.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=/7OzItzkaEvJ7h4xt015A/r1HsxEaQKVQAX2j+LjPfU=; b=ZrZdHQnkSB8ov3Jk69oyHdPxh4l5YCYOScqn9pV6XRJnrNQSNhqembCi1jWaeBqB/HZiEbjhRru3OORq0jxTBpRNLU/QOCK6gBv4o1FjGuI0eCvj4Kxf3g1Oiv7Xfl3U0PABv4EqtajjXtvDlO2ymLLuPOh2IRlJM2oQYitRM7o= Received: from VI1PR05MB4141.eurprd05.prod.outlook.com (52.133.14.15) by VI1PR05MB4512.eurprd05.prod.outlook.com (52.133.14.10) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2644.22; Tue, 21 Jan 2020 14:05:05 +0000 Received: from VI1PR05MB4141.eurprd05.prod.outlook.com ([fe80::1c00:7925:d5c6:d60d]) by VI1PR05MB4141.eurprd05.prod.outlook.com ([fe80::1c00:7925:d5c6:d60d%7]) with mapi id 15.20.2644.027; Tue, 21 Jan 2020 14:05:04 +0000 Received: from mlx.ziepe.ca (12.231.255.114) by DM6PR10CA0034.namprd10.prod.outlook.com (2603:10b6:5:60::47) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2644.20 via Frontend Transport; Tue, 21 Jan 2020 14:05:04 +0000 Received: from jgg by jggl.ziepe.ca with local (Exim 4.90_1) (envelope-from ) id 1itu9I-0002XK-Ro; Tue, 21 Jan 2020 10:04:56 -0400 From: Jason Gunthorpe To: "Michael S. Tsirkin" CC: Jason Wang , Shahaf Shuler , Rob Miller , "linux-kernel@vger.kernel.org" , "kvm@vger.kernel.org" , "virtualization@lists.linux-foundation.org" , Netdev , "Bie, Tiwei" , "maxime.coquelin@redhat.com" , "Liang, Cunming" , "Wang, Zhihong" , "Wang, Xiao W" , "haotian.wang@sifive.com" , "Zhu, Lingshan" , "eperezma@redhat.com" , "lulu@redhat.com" , Parav Pandit , "Tian, Kevin" , "stefanha@redhat.com" , "rdunlap@infradead.org" , "hch@infradead.org" , Ariel Adam , "jakub.kicinski@netronome.com" , Jiri Pirko , "hanand@xilinx.com" , "mhabets@solarflare.com" Subject: Re: [PATCH 3/5] vDPA: introduce vDPA bus Thread-Topic: [PATCH 3/5] vDPA: introduce vDPA bus Thread-Index: AQHVzGqUgTlkW8H4N0+zRVK4Lh0XAKfuxkEAgAAbnwCAAAWygIACz0CAgAGL1YCAAJh1gIAAqtOAgAAds4CAACVEAIAABDeAgABhkgA= Date: Tue, 21 Jan 2020 14:05:04 +0000 Message-ID: <20200121140456.GA12330@mellanox.com> References: <20200117070324-mutt-send-email-mst@kernel.org> <239b042c-2d9e-0eec-a1ef-b03b7e2c5419@redhat.com> <20200120174933.GB3891@mellanox.com> <2a324cec-2863-58f4-c58a-2414ee32c930@redhat.com> <20200121004047-mutt-send-email-mst@kernel.org> <20200121031506-mutt-send-email-mst@kernel.org> In-Reply-To: <20200121031506-mutt-send-email-mst@kernel.org> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-clientproxiedby: DM6PR10CA0034.namprd10.prod.outlook.com (2603:10b6:5:60::47) To VI1PR05MB4141.eurprd05.prod.outlook.com (2603:10a6:803:44::15) authentication-results: spf=none (sender IP is ) smtp.mailfrom=jgg@mellanox.com; x-ms-exchange-messagesentrepresentingtype: 1 x-originating-ip: [12.231.255.114] x-ms-publictraffictype: Email x-ms-office365-filtering-ht: Tenant x-ms-office365-filtering-correlation-id: 4323a93c-c1aa-4c8f-1914-08d79e7aea08 x-ms-traffictypediagnostic: VI1PR05MB4512:|VI1PR05MB4512: x-ms-exchange-transport-forked: True x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:1227; x-forefront-prvs: 0289B6431E x-forefront-antispam-report: SFV:NSPM;SFS:(10009020)(4636009)(39860400002)(136003)(396003)(376002)(346002)(366004)(199004)(189003)(478600001)(86362001)(4744005)(6666004)(81156014)(8676002)(8936002)(81166006)(9746002)(36756003)(66946007)(64756008)(66556008)(66446008)(66476007)(7416002)(2906002)(316002)(6916009)(186003)(71200400001)(5660300002)(4326008)(26005)(52116002)(9786002)(1076003)(33656002)(2616005)(54906003)(24400500001);DIR:OUT;SFP:1101;SCL:1;SRVR:VI1PR05MB4512;H:VI1PR05MB4141.eurprd05.prod.outlook.com;FPR:;SPF:None;LANG:en;PTR:InfoNoRecords;A:1;MX:1; received-spf: None (protection.outlook.com: mellanox.com does not designate permitted sender hosts) x-ms-exchange-senderadcheck: 1 x-microsoft-antispam: BCL:0; x-microsoft-antispam-message-info: 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 Content-Type: text/plain; charset="us-ascii" Content-ID: Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: Mellanox.com X-MS-Exchange-CrossTenant-Network-Message-Id: 4323a93c-c1aa-4c8f-1914-08d79e7aea08 X-MS-Exchange-CrossTenant-originalarrivaltime: 21 Jan 2020 14:05:04.8790 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: a652971c-7d2e-4d9b-a6a4-d149256f461b X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: PhDPNjeuPgSdzALfaPBLpYKFMJMTNqSrvv0GOjfaJIgAvmGpOiGRw+S01V93Mak39dG/uhd41Zf3nHyQOENjSA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: VI1PR05MB4512 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Tue, Jan 21, 2020 at 03:15:43AM -0500, Michael S. Tsirkin wrote: > > This sounds more flexible e.g driver may choose to implement static map= ping > > one through commit. But a question here, it looks to me this still requ= ires > > the DMA to be synced with at least commit here. Otherwise device may ge= t DMA > > fault? Or device is expected to be paused DMA during begin? > >=20 > > Thanks >=20 > For example, commit might switch one set of tables for another, > without need to pause DMA. I'm not aware of any hardware that can do something like this completely atomically.. Any mapping change API has to be based around add/remove regions without any active DMA (ie active DMA is a guest error the guest can be crashed if it does this) Jason