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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EC598C43334 for ; Tue, 21 Jun 2022 04:28:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343660AbiFUE2l (ORCPT ); Tue, 21 Jun 2022 00:28:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49666 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343662AbiFUE21 (ORCPT ); Tue, 21 Jun 2022 00:28:27 -0400 Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1046563BB; Mon, 20 Jun 2022 21:28:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1655785705; x=1687321705; h=message-id:date:mime-version:cc:subject:to:references: from:in-reply-to:content-transfer-encoding; bh=DkFRRkmJt7PsIWwIUdSoJXbh9kQg9crtwrrbrg/6TSU=; b=DlPvM2x8w0JMxSN5/yrRp+9MHNTz7FRXyhYD4zxJO8gM0frOo5D6TbW6 ZR6O5FRxIPAHD50brcIjC8RbPzpQxR0WbxLMs0DAev11Pb6vxMYKUzg6W lcL9pPekhvBL8JIMXYoLOqvY/0P0HYzVRRF0FTaG64Hf5tR/OmvNNTrgt Vee7CX2s3vxcEw/Pe8kFlJABne3wL0wlzGGk3UihKbU7nwmwSWBniJmIJ 7WPviYm5PVqnkZrqWvzT37dG+euDIR2kSchQdlxFPdtrRI/LtdrE8C/WC d2w6gdtKbiuxjbBgRzVHmPcBgxJG1f8SunwHVDoLTI4psQOix2ZAYW827 g==; X-IronPort-AV: E=McAfee;i="6400,9594,10384"; a="344017660" X-IronPort-AV: E=Sophos;i="5.92,207,1650956400"; d="scan'208";a="344017660" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Jun 2022 21:28:24 -0700 X-IronPort-AV: E=Sophos;i="5.92,207,1650956400"; d="scan'208";a="833395659" Received: from zequnyu-mobl1.ccr.corp.intel.com (HELO [10.255.31.162]) ([10.255.31.162]) by fmsmga006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Jun 2022 21:28:22 -0700 Message-ID: <80457871-a760-69ba-70be-5e95344182ea@linux.intel.com> Date: Tue, 21 Jun 2022 12:28:20 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 Cc: baolu.lu@linux.intel.com, "Qiang, Chenyi" , "Liu, Yi L" , "Pan, Jacob jun" , "iommu@lists.linux-foundation.org" , "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" Subject: Re: [PATCH 1/1] iommu/vt-d: Fix RID2PASID setup failure Content-Language: en-US To: "Tian, Kevin" , Joerg Roedel , "Raj, Ashok" References: <20220620081729.4610-1-baolu.lu@linux.intel.com> <5d13cab5-1f0a-51c7-78a3-fb5d3d793ab1@linux.intel.com> From: Baolu Lu In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022/6/21 11:46, Tian, Kevin wrote: >> From: Baolu Lu >> Sent: Tuesday, June 21, 2022 11:39 AM >> >> On 2022/6/21 10:54, Tian, Kevin wrote: >>>> From: Lu Baolu >>>> Sent: Monday, June 20, 2022 4:17 PM >>>> @@ -2564,7 +2564,7 @@ static int domain_add_dev_info(struct >>>> dmar_domain *domain, struct device *dev) >>>> ret = intel_pasid_setup_second_level(iommu, >>>> domain, >>>> dev, PASID_RID2PASID); >>>> spin_unlock_irqrestore(&iommu->lock, flags); >>>> - if (ret) { >>>> + if (ret && ret != -EBUSY) { >>>> dev_err(dev, "Setup RID2PASID failed\n"); >>>> dmar_remove_one_dev_info(dev); >>>> return ret; >>>> -- >>>> 2.25.1 >>> >>> It's cleaner to avoid this error at the first place, i.e. only do the >>> setup when the first device is attached to the pasid table. >> >> The logic that identifies the first device might introduce additional >> unnecessary complexity. Devices that share a pasid table are rare. I >> even prefer to give up sharing tables so that the code can be >> simpler.:-) >> > > It's not that complex if you simply move device_attach_pasid_table() > out of intel_pasid_alloc_table(). Then do the setup if > list_empty(&pasid_table->dev) and then attach device to the > pasid table in domain_add_dev_info(). The pasid table is part of the device, hence a better place to allocate/free the pasid table is in the device probe/release paths. Things will become more complicated if we change relationship between device and it's pasid table when attaching/detaching a domain. That's the reason why I thought it was additional complexity. -- Best regards, baolu