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_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 02E3BC43603 for ; Tue, 17 Dec 2019 01:38:22 +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 C92BA218AC for ; Tue, 17 Dec 2019 01:38:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C92BA218AC 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 913E6226DB; Tue, 17 Dec 2019 01:38:21 +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 G3WyAsrQeKSI; Tue, 17 Dec 2019 01:38:20 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by silver.osuosl.org (Postfix) with ESMTP id 705EA2048F; Tue, 17 Dec 2019 01:38:20 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 60C99C1AE8; Tue, 17 Dec 2019 01:38:20 +0000 (UTC) Received: from hemlock.osuosl.org (smtp2.osuosl.org [140.211.166.133]) by lists.linuxfoundation.org (Postfix) with ESMTP id ACED1C077D for ; Tue, 17 Dec 2019 01:38:18 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by hemlock.osuosl.org (Postfix) with ESMTP id 9457487F5C for ; Tue, 17 Dec 2019 01:38:18 +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 8ahEdK317Fpr for ; Tue, 17 Dec 2019 01:38:18 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga06.intel.com (mga06.intel.com [134.134.136.31]) by hemlock.osuosl.org (Postfix) with ESMTPS id DE6A887E9D for ; Tue, 17 Dec 2019 01:38:17 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 16 Dec 2019 17:38:17 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.69,323,1571727600"; d="scan'208";a="227319645" Received: from allen-box.sh.intel.com (HELO [10.239.159.136]) ([10.239.159.136]) by orsmga002.jf.intel.com with ESMTP; 16 Dec 2019 17:38:14 -0800 Subject: Re: [PATCH v3 5/6] iommu/vt-d: Flush PASID-based iotlb for iova over first level To: "Liu, Yi L" , Joerg Roedel , David Woodhouse , Alex Williamson References: <20191211021219.8997-1-baolu.lu@linux.intel.com> <20191211021219.8997-6-baolu.lu@linux.intel.com> <6a5f6695-d1fd-e7d1-3ea3-f222a1ef0e54@linux.intel.com> From: Lu Baolu Message-ID: Date: Tue, 17 Dec 2019 09:37:22 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.1 MIME-Version: 1.0 In-Reply-To: <6a5f6695-d1fd-e7d1-3ea3-f222a1ef0e54@linux.intel.com> Content-Language: en-US Cc: "Tian, Kevin" , "Raj, Ashok" , "kvm@vger.kernel.org" , "Kumar, Sanjay K" , "iommu@lists.linux-foundation.org" , "linux-kernel@vger.kernel.org" , "Sun, Yi Y" 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-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" Hi again, On 12/17/19 9:19 AM, Lu Baolu wrote: > Hi Yi, > > On 12/15/19 5:22 PM, Liu, Yi L wrote: >> Ok, let me explain more... default pasid is meaningful only when >> the domain has been attached to a device as an aux-domain. right? > > No exactly. Each domain has a specific default pasid, no matter normal > domain (RID based) or aux-domain (PASID based). The difference is for a > normal domain RID2PASID value is used, for an aux-domain the pasid is > allocated from a global pool. > > The same concept used in VT-d 3.x scalable mode. For RID based DMA > translation RID2PASID value is used when walking the tables; For PASID > based DMA translation a real pasid in the transaction is used. > >> If a domain only has one device, and it is attached to this device as >> normal domain (normal domain means non aux-domain here). Then >> you should flush cache with domain-id and RID2PASID value. >> If a domain has one device, and it is attached to this device as >> aux-domain. Then you may want to flush cache with domain-id >> and default pasid. right? > > A domain's counterpart is IOMMU group. So we say attach/detach domain > to/from devices in a group. We don't allow devices with different > default pasid sitting in a same group, right? > >> Then let's come to the case I mentioned in previous email. a mdev >> and another device assigned to a single VM. In host, you will have >> a domain which has two devices, one device(deva) is attached as > > No. We will have two IOMMU groups and two domains. Correct me if my > understanding is not right. Reconsidered this. Unfortunately, my understanding is not right. :-( A single domain could be attached to multiple IOMMU groups. So it comes to the issue you concerned. Do I understand it right? > >> normal domain, another one (devB) is attached as aux-domain. Then >> which pasid should be used when the mapping in IOVA page table is >> modified? RID2PASID or default pasid? I think both should be used >> since the domain means differently to the two devices. If you just >> use default pasid, then deva may still be able to use stale caches. You are right. I will change it accordingly. The logic should look like: if (domain attached to physical device) flush_piotlb_with_RID2PASID() else if (domain_attached_to_mdev_device) flush_piotlb_with_default_pasid() Does this work for you? Thanks for catching this! Best regards, baolu _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu