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 C5F9EC32771 for ; Mon, 20 Jan 2020 20:52:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9248722522 for ; Mon, 20 Jan 2020 20:52:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=Mellanox.com header.i=@Mellanox.com header.b="ZI4tydE3" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727254AbgATUw2 (ORCPT ); Mon, 20 Jan 2020 15:52:28 -0500 Received: from mail-db8eur05on2041.outbound.protection.outlook.com ([40.107.20.41]:61728 "EHLO EUR05-DB8-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726586AbgATUw1 (ORCPT ); Mon, 20 Jan 2020 15:52:27 -0500 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=GinDkqLvzgbmalXmyMtMefJW3nmjuXcgxT87JPD2KJ8goziWb5dFzfRlYwM2zkKB4yWfNi93Wyu6/Jbk9iXdGtIyd26lOp+UgQqFWZwFaPZr/ise/ceHPG523DfZGA/R27pZdy44hZCA2p1uSMYorM2+C009LWp/l2AAZ1DArFpaFK5JSi1EEx1aVFZ/R7VGK8UuIqsiKKJl5XsINBRyl932+/X1lANfPYrsPUj8/g5uIfI+lpg+ZS06ppb8KHwuezXXF4anFaoigHcAG+1T8IoRJ1uXytAJQGtCg9iqOVrlBdNOEA+ifSd5lUQqB+iNb39HghOHGeMLtS6kpRvShQ== 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=BALKI9NsSM2rAos4Vxt8hfbiMtUUjSbmJC1+NsyQhls=; b=Ue4a3PhX7WPKXOWZIgyx3iFfxeF1a33kZlgn6AeWY8b41pmo6I1+MTem0yG/m2FnGMRSHUAAzwH8WzkTSZKrXOc7yJXSlp80jVc95uC4Rfa8VqXoMFMAKKymU+JjyDskbGupuIBhOhBZQn4vl/yvgEy/FjFNVHBoQnpVa+WJpN8mIaVoTT+5mUI6LFyC4VT3GYRabU4ypd1LVolGmCzKhQRbFywbws0in1dglqxfONgaTfryoHFL/P8N2zf6QXFRzO8DNxIyI/1zhSguu3K/qpvTOQxaApS9oWCnOLT2Q96mcJbRrXRiu8KFQCkT8QfX3UJp5SHq22nexDaTHLGN/Q== 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=BALKI9NsSM2rAos4Vxt8hfbiMtUUjSbmJC1+NsyQhls=; b=ZI4tydE3ozP1fwSmARFAldlRlCa6V0gPoLoUp1EFueDMOXStDOTM5Av0SBCbUCo3RxFanW3wSvJ+btrawdXmdYlU40knGAhAmUr3KDaAKf/JUj6siRQWIcpQ57qPl7aFQ53L7TpqnVPtvap47NTK9NZoAtNwt7q/eaitHHtYIfg= Received: from AM0PR0502MB3795.eurprd05.prod.outlook.com (52.133.45.150) by AM0PR0502MB3876.eurprd05.prod.outlook.com (52.133.48.18) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2644.19; Mon, 20 Jan 2020 20:51:44 +0000 Received: from AM0PR0502MB3795.eurprd05.prod.outlook.com ([fe80::d862:228a:d87f:99bb]) by AM0PR0502MB3795.eurprd05.prod.outlook.com ([fe80::d862:228a:d87f:99bb%7]) with mapi id 15.20.2644.026; Mon, 20 Jan 2020 20:51:44 +0000 From: Shahaf Shuler To: Jason Gunthorpe , Jason Wang CC: Rob Miller , "Michael S. Tsirkin" , "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: AQHVzGqTFJN2iC19r0STv/0Uj4sDPafuxkEAgAAbnwCAAAWygIACyO6wgAGSJ4CAAJh8gIAAMkCQ Date: Mon, 20 Jan 2020 20:51:43 +0000 Message-ID: References: <20200116124231.20253-1-jasowang@redhat.com> <20200116124231.20253-4-jasowang@redhat.com> <20200117070324-mutt-send-email-mst@kernel.org> <239b042c-2d9e-0eec-a1ef-b03b7e2c5419@redhat.com> <20200120174933.GB3891@mellanox.com> In-Reply-To: <20200120174933.GB3891@mellanox.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: authentication-results: spf=none (sender IP is ) smtp.mailfrom=shahafs@mellanox.com; x-originating-ip: [31.154.10.105] x-ms-publictraffictype: Email x-ms-office365-filtering-ht: Tenant x-ms-office365-filtering-correlation-id: eb4ec263-5f1e-49ac-f1eb-08d79dea8ee8 x-ms-traffictypediagnostic: AM0PR0502MB3876:|AM0PR0502MB3876: x-ms-exchange-transport-forked: True x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:9508; x-forefront-prvs: 0288CD37D9 x-forefront-antispam-report: SFV:NSPM;SFS:(10009020)(4636009)(376002)(396003)(366004)(346002)(39860400002)(136003)(199004)(189003)(81156014)(81166006)(86362001)(478600001)(8676002)(76116006)(66946007)(52536014)(7416002)(33656002)(8936002)(66446008)(64756008)(66476007)(66556008)(26005)(9686003)(7696005)(6506007)(55016002)(2906002)(186003)(4326008)(316002)(110136005)(54906003)(5660300002)(71200400001);DIR:OUT;SFP:1101;SCL:1;SRVR:AM0PR0502MB3876;H:AM0PR0502MB3795.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: HvYo1urlyLxjeYX7pRDEQ0gytB4zlLC73tpyt2mlGAEcOT7pOrgROhAiDO23XXwimGvk7fquLACm/iwSh2u2UTF64e3obID/6+4hbQdLrUV/f4L0p6/n6XZA2pIMV4HpNBIrvJqDOvZOv3xYtGNF/w92U+8smbeVu40nqkPyy/74Es791dEOVHNLWEug+eHn8ZXpdVhcbiRSXFSQVwKPKF+zYpt2L48tMzHw+KhLS+/i3JObMlafxI0H4hmTRPrLFJuXouEJm+VMj8S01ml7OLwr6NaLlX0alooUM9LhKoRos4IXFrryzSkjrXAUHhWIniEiwdxbUwUQnPqfSAVU1B2Bfw4ZZt7965BvkLAR+XiQe9VhiOUJXY/lVnFzPzCENmQeTKhHQ6zpVcQxMUX1s/QNvAzKUI+XwqRYqOA0XXLZ1dCPkC/0ttuQrR3XHPhr Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: Mellanox.com X-MS-Exchange-CrossTenant-Network-Message-Id: eb4ec263-5f1e-49ac-f1eb-08d79dea8ee8 X-MS-Exchange-CrossTenant-originalarrivaltime: 20 Jan 2020 20:51:44.1143 (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: CBU9dbfDpUmSc4YQKFwCKGAo5AuIV7aQVk+gsSwzKrZWWXEZafcNt/pUrypeB5BuLReiVVdRLIRPd3nTQltu4w== X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM0PR0502MB3876 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Monday, January 20, 2020 7:50 PM, Jason Gunthorpe: > Subject: Re: [PATCH 3/5] vDPA: introduce vDPA bus >=20 > On Mon, Jan 20, 2020 at 04:43:53PM +0800, Jason Wang wrote: > > This is similar to the design of platform IOMMU part of vhost-vdpa. We > > decide to send diffs to platform IOMMU there. If it's ok to do that in > > driver, we can replace set_map with incremental API like map()/unmap(). > > > > Then driver need to maintain rbtree itself. >=20 > I think we really need to see two modes, one where there is a fixed > translation without dynamic vIOMMU driven changes and one that supports > vIOMMU. >=20 > There are different optimization goals in the drivers for these two > configurations. +1. It will be best to have one API for static config (i.e. mapping can be set = only before virtio device gets active), and one API for dynamic changes tha= t can be set after the virtio device is active.=20 >=20 > > > If the first one, then I think memory hotplug is a heavy flow > > > regardless. Do you think the extra cycles for the tree traverse will > > > be visible in any way? > > > > I think if the driver can pause the DMA during the time for setting up > > new mapping, it should be fine. >=20 > This is very tricky for any driver if the mapping change hits the virtio = rings. :( >=20 > Even a IOMMU using driver is going to have problems with that.. >=20 > Jason