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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 5ECCBC432C1 for ; Wed, 25 Sep 2019 06:57:04 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2CD97217F4 for ; Wed, 25 Sep 2019 06:57:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2CD97217F4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id DE683B8E; Wed, 25 Sep 2019 06:57:03 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id CBE3D9CA for ; Wed, 25 Sep 2019 06:57:02 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 746C08B2 for ; Wed, 25 Sep 2019 06:56:54 +0000 (UTC) Received: from mail-pf1-f199.google.com (mail-pf1-f199.google.com [209.85.210.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 02754C059758 for ; Wed, 25 Sep 2019 06:56:54 +0000 (UTC) Received: by mail-pf1-f199.google.com with SMTP id v6so3305504pfm.1 for ; Tue, 24 Sep 2019 23:56:53 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=ijT0fpBaBgG6WmvEUpSA+esMu5WxoRviWQWfgADFoo4=; b=RPaFqySiyYq9viNW+xu5fyp+EiTHGFE4dOLPRZPABR7lWCxj44DhLFh0ArbIffQ1rV lnhPMGOcLyKz4/C2uD+EspCOwsNkOir/HfmHHlG21KOXZ082Hy75vVMRJ2Ah3EdFdFPJ BzFL0dY6nnZFqWqoUh3ThICjV3DL8EOH4I4XrI07cW0N5VQ4w/DtxoHmTfI7lwl+sGqQ l8GeOFQxIBnRSHQK0Q7abfi/Amh1Nqcuagn9Kzf0cgC02aOFqmK5WTZ6YlagaCIp+6OX M3EQPzFx/WrekaW+BRpdw65hwNyI55Hnbg1bwHe8j1YBzmGXo27w+CD2evc7ShcaPtBx gZIA== X-Gm-Message-State: APjAAAV5irullYoIQNlNYQ+pBi8ge+aPR0OMDzhYnlTf8Rfa/OQBktDa y0XwLPm1cFjOIxwcZbiHyBq4+KMeb7anDyUC/OYw+CkbASw+uBZ9vy3c6+B4u0zaOg6OJjq9NiR if+DQ5XhYKcQwfZv+0PRStI8+ymyDUA== X-Received: by 2002:aa7:91d4:: with SMTP id z20mr8178146pfa.131.1569394613574; Tue, 24 Sep 2019 23:56:53 -0700 (PDT) X-Google-Smtp-Source: APXvYqyEQscMvlt2r5p9VzQw9b3ybPcThukuDsFI9KDVwsVjgxUw63WdPiTX25gqJqaKL+BCyIqXjg== X-Received: by 2002:aa7:91d4:: with SMTP id z20mr8178134pfa.131.1569394613417; Tue, 24 Sep 2019 23:56:53 -0700 (PDT) Received: from xz-x1 ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id g24sm6184543pgn.90.2019.09.24.23.56.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 24 Sep 2019 23:56:52 -0700 (PDT) Date: Wed, 25 Sep 2019 14:56:40 +0800 From: Peter Xu To: Lu Baolu Subject: Re: [RFC PATCH 0/4] Use 1st-level for DMA remapping in guest Message-ID: <20190925065640.GO28074@xz-x1> References: <20190923122454.9888-1-baolu.lu@linux.intel.com> <20190923122715.53de79d0@jacob-builder> <20190923202552.GA21816@araj-mobl1.jf.intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.4 (2019-03-13) Cc: "Tian, Kevin" , Alex Williamson , "Raj, Ashok" , "kvm@vger.kernel.org" , "Kumar, Sanjay K" , "iommu@lists.linux-foundation.org" , "linux-kernel@vger.kernel.org" , "Sun, Yi Y" , David Woodhouse X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: iommu-bounces@lists.linux-foundation.org Errors-To: iommu-bounces@lists.linux-foundation.org On Wed, Sep 25, 2019 at 10:48:32AM +0800, Lu Baolu wrote: > Hi Kevin, > > On 9/24/19 3:00 PM, Tian, Kevin wrote: > > > > > '-----------' > > > > > '-----------' > > > > > > > > > > This patch series only aims to achieve the first goal, a.k.a using > > first goal? then what are other goals? I didn't spot such information. > > > > The overall goal is to use IOMMU nested mode to avoid shadow page table > and VMEXIT when map an gIOVA. This includes below 4 steps (maybe not > accurate, but you could get the point.) > > 1) GIOVA mappings over 1st-level page table; > 2) binding vIOMMU 1st level page table to the pIOMMU; > 3) using pIOMMU second level for GPA->HPA translation; > 4) enable nested (a.k.a. dual stage) translation in host. > > This patch set aims to achieve 1). Would it make sense to use 1st level even for bare-metal to replace the 2nd level? What I'm thinking is the DPDK apps - they have MMU page table already there for the huge pages, then if they can use 1st level as the default device page table then it even does not need to map, because it can simply bind the process root page table pointer to the 1st level page root pointer of the device contexts that it uses. Regards, -- Peter Xu _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu