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=-2.5 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 3F590C433DF for ; Thu, 2 Jul 2020 06:22:46 +0000 (UTC) Received: from silver.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (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 1010820874 for ; Thu, 2 Jul 2020 06:22:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1010820874 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 silver.osuosl.org (Postfix) with ESMTP id A302026316; Thu, 2 Jul 2020 06:22:45 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from silver.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id VOAW7Z3Tag6U; Thu, 2 Jul 2020 06:22:44 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by silver.osuosl.org (Postfix) with ESMTP id 81B62253CA; Thu, 2 Jul 2020 06:22:43 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 65A0CC0865; Thu, 2 Jul 2020 06:22:43 +0000 (UTC) Received: from silver.osuosl.org (smtp3.osuosl.org [140.211.166.136]) by lists.linuxfoundation.org (Postfix) with ESMTP id 6257FC0733 for ; Thu, 2 Jul 2020 06:22:42 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by silver.osuosl.org (Postfix) with ESMTP id 3AD4F26316 for ; Thu, 2 Jul 2020 06:22:42 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from silver.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Xlf6mGqMXC9P for ; Thu, 2 Jul 2020 06:22:41 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by silver.osuosl.org (Postfix) with ESMTPS id 6796A253CA for ; Thu, 2 Jul 2020 06:22:41 +0000 (UTC) IronPort-SDR: hBA5c9yjKzaLn6hJQi7FURedcb77EjmBhsY7FPVDZsCvoAvm9nvJW5Fx0kSlJVWWDD8IzeOV2H 6zZF5P6yTmcQ== X-IronPort-AV: E=McAfee;i="6000,8403,9669"; a="164866038" X-IronPort-AV: E=Sophos;i="5.75,303,1589266800"; d="scan'208";a="164866038" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Jul 2020 23:22:40 -0700 IronPort-SDR: LIeRYbr2nmV6Iwj4ogP9DmdggqXOqeepFNfDsGQSMbLg7LNVOyZYo2tuMuXdmKSlzm12jCJqNu y6oFkQ7/SvlQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.75,303,1589266800"; d="scan'208";a="455400649" Received: from jacob-builder.jf.intel.com (HELO jacob-builder) ([10.7.199.155]) by orsmga005.jf.intel.com with ESMTP; 01 Jul 2020 23:22:40 -0700 Date: Wed, 1 Jul 2020 23:29:16 -0700 From: Jacob Pan To: Jean-Philippe Brucker , "Raj, Ashok" Subject: IOASID set token Message-ID: <20200701232916.38fd7908@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" , "Lu, Baolu" , "iommu@lists.linux-foundation.org" , "Wu, Hao" 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" Hi Jean, Have a question for you on whether we can have a fixed token type for ioasid_set. Currently, ioasid_set has an arbitrary token. For VT-d vSVA usage, we choose mm as ioasid_set token to identify PASIDs within a guest. We have multiple in-kernel users of PASIDs such as VFIO, KVM, and VDCM. When an IOASID set is created, there is not a good way to communicate about the token choices. So we have to let VDCM and KVM *assume* mm is used as token, then retrieve ioasid_set based on the token. This assumption of "mm as token" is not a reliable SW architecture. So we are thinking if we can have an explicit ioasid_set token type where mm is used. After all, PASID and mm are closely related. The code change might be the following: 1. add a flag to indicate token type when ioasid_set is allocated, e.g. IOASID_SET_TYPE_MM IOASID_SET_TYPE_ANY 2. other users of the ioasid_set can query if an mm token exists based on the flag IOASID_SET_TYPE_MM, then retrieve the ioasid_set. Existing ioasid_set user can still use arbitrary token under the flag IOASID_SET_TYPE_ANY Would this be an issue for ARM usage? Thanks, Jacob _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu