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=-2.3 required=3.0 tests=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 36253C32774 for ; Fri, 27 Sep 2019 08:07:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 17EF5217D7 for ; Fri, 27 Sep 2019 08:07:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726440AbfI0IHB (ORCPT ); Fri, 27 Sep 2019 04:07:01 -0400 Received: from mga07.intel.com ([134.134.136.100]:1691 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725804AbfI0IHB (ORCPT ); Fri, 27 Sep 2019 04:07:01 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 27 Sep 2019 01:07:00 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,554,1559545200"; d="scan'208";a="201940621" Received: from dpdk-virtio-tbie-2.sh.intel.com (HELO ___) ([10.67.104.73]) by orsmga002.jf.intel.com with ESMTP; 27 Sep 2019 01:06:58 -0700 Date: Fri, 27 Sep 2019 16:04:10 +0800 From: Tiwei Bie To: Jason Wang Cc: mst@redhat.com, alex.williamson@redhat.com, maxime.coquelin@redhat.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, dan.daly@intel.com, cunming.liang@intel.com, zhihong.wang@intel.com, lingshan.zhu@intel.com Subject: Re: [PATCH] vhost: introduce mdev based hardware backend Message-ID: <20190927080410.GA22568@___> References: <20190926045427.4973-1-tiwei.bie@intel.com> <1b4b8891-8c14-1c85-1d6a-2eed1c90bcde@redhat.com> <20190927045438.GA17152@___> <49bb0777-3761-3737-8e5b-568957f9a935@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <49bb0777-3761-3737-8e5b-568957f9a935@redhat.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, Sep 27, 2019 at 03:14:42PM +0800, Jason Wang wrote: > On 2019/9/27 下午12:54, Tiwei Bie wrote: > > > > + > > > > + /* > > > > + * In vhost-mdev, userspace should pass ring addresses > > > > + * in guest physical addresses when IOMMU is disabled or > > > > + * IOVAs when IOMMU is enabled. > > > > + */ > > > A question here, consider we're using noiommu mode. If guest physical > > > address is passed here, how can a device use that? > > > > > > I believe you meant "host physical address" here? And it also have the > > > implication that the HPA should be continuous (e.g using hugetlbfs). > > The comment is talking about the virtual IOMMU (i.e. iotlb in vhost). > > It should be rephrased to cover the noiommu case as well. Thanks for > > spotting this. > > > So the question still, if GPA is passed how can it be used by the > virtio-mdev device? Sorry if I didn't make it clear.. Of course, GPA can't be passed in noiommu mode. > > Thanks >