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Tsirkin" CC: Shahaf Shuler , Jason Wang , 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+zRVK4Lh0XAKfuxkEAgAAbnwCAAAWygIACz0CAgAGL1YCAAJh1gIAAMuaAgAAJaICAARgbgA== Date: Tue, 21 Jan 2020 14:07:59 +0000 Message-ID: <20200121140755.GB12330@mellanox.com> 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> <20200120162449-mutt-send-email-mst@kernel.org> In-Reply-To: <20200120162449-mutt-send-email-mst@kernel.org> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-clientproxiedby: SN4PR0701CA0026.namprd07.prod.outlook.com (2603:10b6:803:2d::24) 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: acf5f34e-40fd-4f16-9a8c-08d79e7b5218 x-ms-traffictypediagnostic: VI1PR05MB4512:|VI1PR05MB4512: x-ms-exchange-transport-forked: True x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:8882; x-forefront-prvs: 0289B6431E x-forefront-antispam-report: SFV:NSPM;SFS:(10009020)(4636009)(39860400002)(136003)(396003)(376002)(346002)(366004)(199004)(189003)(478600001)(86362001)(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: acf5f34e-40fd-4f16-9a8c-08d79e7b5218 X-MS-Exchange-CrossTenant-originalarrivaltime: 21 Jan 2020 14:07:59.3113 (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: r3DzMNMycWf7/ozGh2jSMLYD45/MXQhC94LNiWOZzGprK9HQyZ7VTnoiuvi2bEFNGvMoaNiu0LMcgNaSrixtDg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: VI1PR05MB4512 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 20, 2020 at 04:25:23PM -0500, Michael S. Tsirkin wrote: > On Mon, Jan 20, 2020 at 08:51:43PM +0000, Shahaf Shuler wrote: > > 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()/unma= p(). > > > > > > > > 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 suppor= ts > > > vIOMMU. > > >=20 > > > There are different optimization goals in the drivers for these two > > > configurations. > >=20 > > +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 that can be set after the virtio device is active.=20 >=20 > Frankly I don't see when we'd use the static one. > Memory hotplug is enabled for most guests... If someone wants to run a full performance application, like dpdk, then they may wish to trade memory hotplug in that VM for more performance. Perhaps Shahaf can quantify the performance delta? Jason