From patchwork Wed May 27 16:56:15 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jon Derrick X-Patchwork-Id: 11573579 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 588D514F6 for ; Wed, 27 May 2020 16:56:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 407CB2088E for ; Wed, 27 May 2020 16:56:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726748AbgE0Q4X (ORCPT ); Wed, 27 May 2020 12:56:23 -0400 Received: from mga12.intel.com ([192.55.52.136]:24078 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726363AbgE0Q4X (ORCPT ); Wed, 27 May 2020 12:56:23 -0400 IronPort-SDR: tAcCzAGIpsnkk9NM4FHtMZvRNvb6Oaz9rn9nOLHgR8OG0aOfJl5ltbUoPCy77bY4vXdP1EB7va 14zd7Xhc4pJw== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 May 2020 09:56:22 -0700 IronPort-SDR: ljnwbifSi6tpzAZRS3tJCSTDtQX25lWKO+sp42EQ+RzMLhQIPq+xmCqfGncYN7KLMv6U+22KyH DxL7UDXCiPgw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,442,1583222400"; d="scan'208";a="302522293" Received: from jderrick-mobl.amr.corp.intel.com ([10.209.128.69]) by orsmga008.jf.intel.com with ESMTP; 27 May 2020 09:56:21 -0700 From: Jon Derrick To: Cc: , Joerg Roedel , Lu Baolu , Jacob Pan , Sai Praneeth Prakhya , Ashok Raj , Jon Derrick Subject: [PATCH v1 1/3] iommu/vt-d: Only clear real DMA device's context entries Date: Wed, 27 May 2020 10:56:15 -0600 Message-Id: <20200527165617.297470-2-jonathan.derrick@intel.com> X-Mailer: git-send-email 2.25.4 In-Reply-To: <20200527165617.297470-1-jonathan.derrick@intel.com> References: <20200527165617.297470-1-jonathan.derrick@intel.com> MIME-Version: 1.0 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Domain context mapping can encounter issues with sub-devices of a real DMA device. A sub-device cannot have a valid context entry due to it potentially aliasing another device's 16-bit ID. It's expected that sub-devices of the real DMA device uses the real DMA device's requester when context mapping. This is an issue when a sub-device is removed where the context entry is cleared for all aliases. Other sub-devices are still valid, resulting in those sub-devices being stranded without valid context entries. The correct approach is to use the real DMA device when programming the context entries. The insertion path is correct because device_to_iommu() will return the bus and devfn of the real DMA device. The removal path needs to only operate on the real DMA device, otherwise the entire context entry would be cleared for all sub-devices of the real DMA device. This patch also adds a helper to determine if a struct device is a sub-device of a real DMA device. Signed-off-by: Jon Derrick Acked-by: Lu Baolu --- drivers/iommu/intel-iommu.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index ff5a30a..1ff45b2 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -2500,6 +2500,12 @@ static int domain_setup_first_level(struct intel_iommu *iommu, flags); } +static bool dev_is_real_dma_subdevice(struct device *dev) +{ + return dev && dev_is_pci(dev) && + pci_real_dma_dev(to_pci_dev(dev)) != to_pci_dev(dev); +} + static struct dmar_domain *dmar_insert_one_dev_info(struct intel_iommu *iommu, int bus, int devfn, struct device *dev, @@ -4975,7 +4981,8 @@ static void __dmar_remove_one_dev_info(struct device_domain_info *info) PASID_RID2PASID, false); iommu_disable_dev_iotlb(info); - domain_context_clear(iommu, info->dev); + if (!dev_is_real_dma_subdevice(info->dev)) + domain_context_clear(iommu, info->dev); intel_pasid_free_table(info->dev); }