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,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 3B2CCC433DF for ; Thu, 2 Jul 2020 13:41:54 +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 0E81B20899 for ; Thu, 2 Jul 2020 13:41:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0E81B20899 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 D76798A828; Thu, 2 Jul 2020 13:41:53 +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 fkU8nz83mo+C; Thu, 2 Jul 2020 13:41:53 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by hemlock.osuosl.org (Postfix) with ESMTP id 557918A827; Thu, 2 Jul 2020 13:41:53 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 3A937C0888; Thu, 2 Jul 2020 13:41:53 +0000 (UTC) Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137]) by lists.linuxfoundation.org (Postfix) with ESMTP id B02E9C0733 for ; Thu, 2 Jul 2020 13:41:52 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by fraxinus.osuosl.org (Postfix) with ESMTP id 97FAB89019 for ; Thu, 2 Jul 2020 13:41:52 +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 dDGcH1EBJYqH for ; Thu, 2 Jul 2020 13:41:51 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) by fraxinus.osuosl.org (Postfix) with ESMTPS id 418B588F56 for ; Thu, 2 Jul 2020 13:41:51 +0000 (UTC) IronPort-SDR: hxACLdea+N6/YvmRG63MY73ZQcKE+ad3VrCA9JXL206R89Qxb++oQSplEqI6giV4sGtGQVcIyy oToflcdl8ivQ== X-IronPort-AV: E=McAfee;i="6000,8403,9669"; a="134348606" X-IronPort-AV: E=Sophos;i="5.75,304,1589266800"; d="scan'208";a="134348606" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Jul 2020 06:41:50 -0700 IronPort-SDR: wFf9IowRhIrrxXAfe0HAhCgpuT7c0GGXXdivPPwUowrtH8FRJGqQIZ8lF2g+3RsvpWBjPH1JZU iii9fIyjMu4A== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.75,304,1589266800"; d="scan'208";a="304250473" Received: from jacob-builder.jf.intel.com (HELO jacob-builder) ([10.7.199.155]) by fmsmga004.fm.intel.com with ESMTP; 02 Jul 2020 06:41:50 -0700 Date: Thu, 2 Jul 2020 06:48:25 -0700 From: Jacob Pan To: Jean-Philippe Brucker , "Raj, Ashok" , "jean-philippe@linaro.org" Subject: Re: IOASID set token Message-ID: <20200702064825.20f9d2b1@jacob-builder> In-Reply-To: <20200701232916.38fd7908@jacob-builder> References: <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, Just realized I should send this to your Linaro account instead of ARM. So Hi again :) On Wed, 1 Jul 2020 23:29:16 -0700 Jacob Pan wrote: > 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 [Jacob Pan] _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu