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_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 0B0F9C2BA19 for ; Tue, 14 Apr 2020 16:00:46 +0000 (UTC) Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137]) (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 CA84620656 for ; Tue, 14 Apr 2020 16:00:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CA84620656 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 fraxinus.osuosl.org (Postfix) with ESMTP id A7E428574F; Tue, 14 Apr 2020 16:00:45 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from fraxinus.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id rqmqZmgHSbyO; Tue, 14 Apr 2020 16:00:45 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by fraxinus.osuosl.org (Postfix) with ESMTP id 249D884D74; Tue, 14 Apr 2020 16:00:45 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 054DDC1D7D; Tue, 14 Apr 2020 16:00:45 +0000 (UTC) Received: from hemlock.osuosl.org (smtp2.osuosl.org [140.211.166.133]) by lists.linuxfoundation.org (Postfix) with ESMTP id DFAEFC0172 for ; Tue, 14 Apr 2020 16:00:43 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by hemlock.osuosl.org (Postfix) with ESMTP id D7D3287B4D for ; Tue, 14 Apr 2020 16:00:43 +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 1b5PDMRp77Qv for ; Tue, 14 Apr 2020 16:00:42 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by hemlock.osuosl.org (Postfix) with ESMTPS id 9436A87AFE for ; Tue, 14 Apr 2020 16:00:42 +0000 (UTC) IronPort-SDR: wQxqXLsZa+liNrfmPcoh5MH6bpKZ3ST3H6ml/Xkav8gUIk8oONrhRtLD/KPx3GbaybZZo54Jci eHH7isJ1Kxyw== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Apr 2020 09:00:41 -0700 IronPort-SDR: FM4ZlxhcT/aVlmT/AZL2mrP/IwuvOXgnjOtMwfo/CPoCI2buYptuu+D3vIGFEttw4e8azX4WEW IGORjgXUp+3w== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.72,382,1580803200"; d="scan'208";a="399994497" Received: from jacob-builder.jf.intel.com (HELO jacob-builder) ([10.7.199.155]) by orsmga004.jf.intel.com with ESMTP; 14 Apr 2020 09:00:41 -0700 Date: Tue, 14 Apr 2020 09:06:36 -0700 From: Jacob Pan To: Christoph Hellwig Subject: Re: [PATCH v2 1/3] iommu/uapi: Define uapi version and capabilities Message-ID: <20200414090636.1798d0c2@jacob-builder> In-Reply-To: <20200414081107.GA7315@infradead.org> References: <20200327074702.GA27959@infradead.org> <20200327165335.397f24a3@jacob-builder> <20200330090746.23c5599c@jacob-builder> <20200331085444.44bee0bb@jacob-builder> <20200402113604.6eea1e6f@jacob-builder> <20200413134157.395981a6@jacob-builder> <20200414081107.GA7315@infradead.org> 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" , Jean-Philippe Brucker , LKML , "iommu@lists.linux-foundation.org" , Alex Williamson , 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 Tue, 14 Apr 2020 01:11:07 -0700 Christoph Hellwig wrote: > On Mon, Apr 13, 2020 at 01:41:57PM -0700, Jacob Pan wrote: > > Hi All, > > > > Just a gentle reminder, any feedback on the options I listed below? > > New ideas will be even better. > > > > Christoph, does the explanation make sense to you? We do have the > > capability/flag based scheme for IOMMU API extension, the version is > > mainly used for size lookup. Compatibility checking is another use > > of the version, it makes checking easy when a vIOMMU is launched. > > No. If you truely need different versions use different ioctl > identifiers. OK. I will drop the global version and keep the current per API/IOCTL struct. > If it really is just the size pass the size and not a > version. OK, I think we have a path forward. I will remove the size-version lookup. My concern was that since we cannot trust the size provided by userspace. We must sanity check the argsz based on knowledge of the struct within the kernel. AFAIK, VFIO does this check by looking at offsetofend(user_struct, last_element). But in this case, VFIO is not the end consumer, and last_element can be a variable size union. So we'd better let IOMMU driver deal with it. _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu