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,USER_AGENT_SANE_2 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 2D0FBC433DF for ; Tue, 16 Jun 2020 15:15:49 +0000 (UTC) Received: from hemlock.osuosl.org (smtp2.osuosl.org [140.211.166.133]) (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 E9BEF207C3 for ; Tue, 16 Jun 2020 15:15:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E9BEF207C3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by hemlock.osuosl.org (Postfix) with ESMTP id 9D5ED89498; Tue, 16 Jun 2020 15:15:48 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from hemlock.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id mcfEg-6ftKUI; Tue, 16 Jun 2020 15:15:48 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by hemlock.osuosl.org (Postfix) with ESMTP id 17E2E890D5; Tue, 16 Jun 2020 15:15:48 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 02DA9C0888; Tue, 16 Jun 2020 15:15:48 +0000 (UTC) Received: from hemlock.osuosl.org (smtp2.osuosl.org [140.211.166.133]) by lists.linuxfoundation.org (Postfix) with ESMTP id A5B23C016E for ; Tue, 16 Jun 2020 15:15:46 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by hemlock.osuosl.org (Postfix) with ESMTP id A18688947D for ; Tue, 16 Jun 2020 15:15:46 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from hemlock.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id QIArmgXFX8Tg for ; Tue, 16 Jun 2020 15:15:46 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by hemlock.osuosl.org (Postfix) with ESMTPS id EBFBE890D5 for ; Tue, 16 Jun 2020 15:15:45 +0000 (UTC) IronPort-SDR: m2YgwiB4mfRgK7H4IXPuPxcGSpUhKOBAqXuhLAPdJicmRFmbfX6I9ip1Q6KPFI9VRjrupmjRA6 Z4lL1nOwLhRg== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Jun 2020 08:15:45 -0700 IronPort-SDR: n1885/AvwQW6RHQ0gOhNxz+f6MggStKTc9mydEKv3qqA/HV3Ui8qqtqJd04eZ19F61nluF+pUP wNsPZKWJuJGw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,518,1583222400"; d="scan'208";a="449871882" Received: from jacob-builder.jf.intel.com (HELO jacob-builder) ([10.7.199.155]) by orsmga005.jf.intel.com with ESMTP; 16 Jun 2020 08:15:44 -0700 Date: Tue, 16 Jun 2020 08:22:12 -0700 From: Jacob Pan To: Alex Williamson Subject: Re: [PATCH v2 1/3] docs: IOMMU user API Message-ID: <20200616082212.0c1611dd@jacob-builder> In-Reply-To: <20200611172727.78dbb822@jacob-builder> References: <1591848735-12447-1-git-send-email-jacob.jun.pan@linux.intel.com> <1591848735-12447-2-git-send-email-jacob.jun.pan@linux.intel.com> <20200611094741.6d118fa8@w520.home> <20200611125205.1e0280d3@jacob-builder> <20200611144047.79613c32@x1.home> <20200611172727.78dbb822@jacob-builder> Organization: OTC X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Cc: "Tian, Kevin" , Raj Ashok , Jonathan Corbet , Jean-Philippe Brucker , LKML , Christoph Hellwig , iommu@lists.linux-foundation.org, David Woodhouse X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 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 Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On Thu, 11 Jun 2020 17:27:27 -0700 Jacob Pan wrote: > > > > But then I thought it even better if VFIO leaves the entire > > copy_from_user() to the layer consuming it. > > > OK. Sounds good, that was what Kevin suggested also. I just wasn't > sure how much VFIO wants to inspect, I thought VFIO layer wanted to > do a sanity check. > > Anyway, I will move copy_from_user to iommu uapi layer. Just one more point brought up by Yi when we discuss this offline. If we move copy_from_user to iommu uapi layer, then there will be multiple copy_from_user calls for the same data when a VFIO container has multiple domains, devices. For bind, it might be OK. But might be additional overhead for TLB flush request from the guest. Thoughts? Jacob _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu