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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 187F2C33CAA for ; Tue, 21 Jan 2020 03:33:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CDEE42073D for ; Tue, 21 Jan 2020 03:33:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="jDGbw4I2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728803AbgAUDdJ (ORCPT ); Mon, 20 Jan 2020 22:33:09 -0500 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:25271 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727009AbgAUDdJ (ORCPT ); Mon, 20 Jan 2020 22:33:09 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1579577587; h=from:from: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; bh=eZ9hoh4EXoAUSSoaNodF/53MT2MqP0i4YheKRaQPqJ0=; b=jDGbw4I2SK2BgOroGeQINVP4J8nlLqhr6RrJ8fpAMNp3CnjESfEsO5vby4g3jQAcZlNrT2 1Ue4uusDG3T6njGq920JYpXTshYHahpgTXl+ORcMC+etJsp3wQq+QVyPjtqXSHQEo+YS6d D/k8J4PhP+K6ZV3ZUnmM/g+qHLYo/H4= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-322-IXrE8Sy2N--LpvrBi-r7Rg-1; Mon, 20 Jan 2020 22:33:05 -0500 X-MC-Unique: IXrE8Sy2N--LpvrBi-r7Rg-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9F6FD107ACC4; Tue, 21 Jan 2020 03:33:02 +0000 (UTC) Received: from [10.72.12.208] (ovpn-12-208.pek2.redhat.com [10.72.12.208]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3646D5C290; Tue, 21 Jan 2020 03:32:44 +0000 (UTC) Subject: Re: [PATCH 3/5] vDPA: introduce vDPA bus To: "Michael S. Tsirkin" Cc: Shahaf Shuler , Rob Miller , "linux-kernel@vger.kernel.org" , "kvm@vger.kernel.org" , "virtualization@lists.linux-foundation.org" , Netdev , "Bie, Tiwei" , Jason Gunthorpe , "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" 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> <20200119045849-mutt-send-email-mst@kernel.org> <20200120070710-mutt-send-email-mst@kernel.org> From: Jason Wang Message-ID: Date: Tue, 21 Jan 2020 11:32:43 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20200120070710-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Content-Transfer-Encoding: quoted-printable Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020/1/20 =E4=B8=8B=E5=8D=888:09, Michael S. Tsirkin wrote: > On Mon, Jan 20, 2020 at 04:44:34PM +0800, Jason Wang wrote: >> On 2020/1/19 =E4=B8=8B=E5=8D=885:59, Michael S. Tsirkin wrote: >>> On Sun, Jan 19, 2020 at 09:07:09AM +0000, Shahaf Shuler wrote: >>>>> Technically, we can keep the incremental API >>>>> here and let the vendor vDPA drivers to record the full mapping >>>>> internally which may slightly increase the complexity of vendor dri= ver. >>>> What will be the trigger for the driver to know it received the last= mapping on this series and it can now push it to the on-chip IOMMU? >>> Some kind of invalidate API? >>> >> The problem is how to deal with the case of vIOMMU. When vIOMMU is ena= bling >> there's no concept of last mapping. >> >> Thanks > Most IOMMUs have a translation cache so have an invalidate API too. Ok, then I get you. But in this case, when vIOMMU is enabled, each new map became a "last=20 mapping". Thanks >