From nobody Fri Sep 12 16:19:03 2025 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 A0895C636D3 for ; Wed, 8 Feb 2023 17:17:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229630AbjBHRRC (ORCPT ); Wed, 8 Feb 2023 12:17:02 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46774 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231768AbjBHRQ4 (ORCPT ); Wed, 8 Feb 2023 12:16:56 -0500 Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C64AD2701; Wed, 8 Feb 2023 09:16:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1675876605; x=1707412605; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=nl2OUQ7BdrvxDP7SzGL7J/lTrhswqlssdfXHqoQ7T2Y=; b=nZ2PWwpT4TdMxrz0QJyBmd4Cei+p+Jayanfm1gAlC5XSgoSrjx7Lx/6s 7jGU6Vkp1BH6S8Egj46s4Zdj4U73fWKl3CU7emQjG435FYrjgcgJvPhZb eH5QmbWV1YAq5K6PEFDALhzIIXQ97Xtf1hFYhYJTYNypk0gy63D5zV9lt uVTnjA8EqBtou9B9cmvdivWC+nOrcAUORrPOh5CvHpLfrOAJVZdNfFc7f E5pU5iLOKC1Na4yp7/S+FEbyYKAB4/1WUh1u88W8mg2GqxVBSINUfySEe RuCc/60joTpuaXxgLxodbnHrPBDOGfFQ7umg1sfVMczmjzmD5LT+IoDFu A==; X-IronPort-AV: E=McAfee;i="6500,9779,10615"; a="309510719" X-IronPort-AV: E=Sophos;i="5.97,281,1669104000"; d="scan'208";a="309510719" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Feb 2023 09:15:27 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10615"; a="810019514" X-IronPort-AV: E=Sophos;i="5.97,281,1669104000"; d="scan'208";a="810019514" Received: from srinivas-otcpl-7600.jf.intel.com (HELO jacob-builder.jf.intel.com) ([10.54.39.106]) by fmsmga001.fm.intel.com with ESMTP; 08 Feb 2023 09:15:26 -0800 From: Jacob Pan To: LKML , iommu@lists.linux.dev, "Lu Baolu" , Joerg Roedel Cc: David Woodhouse , Raj Ashok , "Tian, Kevin" , Yi Liu , Jacob Pan , stable@vger.kernel.org, Sukumar Ghorai Subject: [PATCH v3] iommu/vt-d: Fix PASID directory pointer coherency Date: Wed, 8 Feb 2023 09:19:02 -0800 Message-Id: <20230208171902.1580104-1-jacob.jun.pan@linux.intel.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" On platforms that do not support IOMMU Extended capability bit 0 Page-walk Coherency, CPU caches are not snooped when IOMMU is accessing any translation structures. IOMMU access goes only directly to memory. Intel IOMMU code was missing a flush for the PASID table directory that resulted in the unrecoverable fault as shown below. This patch adds clflush calls whenever allocating and updating a PASID table directory to ensure cache coherency. On the reverse direction, there's no need to clflush the PASID directory pointer when we deactivate a context entry in that IOMMU hardware will not see the old PASID directory pointer after we clear the context entry. PASID directory entries are also never freed once allocated. [ 0.555386] DMAR: DRHD: handling fault status reg 3 [ 0.555805] DMAR: [DMA Read NO_PASID] Request device [00:0d.2] fault add= r 0x1026a4000 [fault reason 0x51] SM: Present bit in Directory Entry is cle= ar [ 0.556348] DMAR: Dump dmar1 table entries for IOVA 0x1026a4000 [ 0.556348] DMAR: scalable mode root entry: hi 0x0000000102448001, low 0= x0000000101b3e001 [ 0.556348] DMAR: context entry: hi 0x0000000000000000, low 0x0000000101= b4d401 [ 0.556348] DMAR: pasid dir entry: 0x0000000101b4e001 [ 0.556348] DMAR: pasid table entry[0]: 0x0000000000000109 [ 0.556348] DMAR: pasid table entry[1]: 0x0000000000000001 [ 0.556348] DMAR: pasid table entry[2]: 0x0000000000000000 [ 0.556348] DMAR: pasid table entry[3]: 0x0000000000000000 [ 0.556348] DMAR: pasid table entry[4]: 0x0000000000000000 [ 0.556348] DMAR: pasid table entry[5]: 0x0000000000000000 [ 0.556348] DMAR: pasid table entry[6]: 0x0000000000000000 [ 0.556348] DMAR: pasid table entry[7]: 0x0000000000000000 [ 0.556348] DMAR: PTE not present at level 4 Cc: Fixes: 0bbeb01a4faf ("iommu/vt-d: Manage scalalble mode PASID tables") Reported-by: Sukumar Ghorai Signed-off-by: Ashok Raj Signed-off-by: Jacob Pan --- v3: Add clflush after PASID directory allocation to prevent malicious device attack with unauthorized PASIDs. Also flush all the PASID entries after directory updates. (Baolu) v2: Add clflush to PASID directory update case (Baolu, Kevin review) --- drivers/iommu/intel/iommu.c | 2 ++ drivers/iommu/intel/pasid.c | 7 +++++++ 2 files changed, 9 insertions(+) diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index 59df7e42fd53..161342e7149d 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -1976,6 +1976,8 @@ static int domain_context_mapping_one(struct dmar_dom= ain *domain, pds =3D context_get_sm_pds(table); context->lo =3D (u64)virt_to_phys(table->table) | context_pdts(pds); + if (!ecap_coherent(iommu->ecap)) + clflush_cache_range(table->table, sizeof(u64)); =20 /* Setup the RID_PASID field: */ context_set_sm_rid2pasid(context, PASID_RID2PASID); diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c index fb3c7020028d..979f796175b1 100644 --- a/drivers/iommu/intel/pasid.c +++ b/drivers/iommu/intel/pasid.c @@ -128,6 +128,9 @@ int intel_pasid_alloc_table(struct device *dev) pasid_table->max_pasid =3D 1 << (order + PAGE_SHIFT + 3); info->pasid_table =3D pasid_table; =20 + if (!ecap_coherent(info->iommu->ecap)) + clflush_cache_range(pasid_table->table, size); + return 0; } =20 @@ -215,6 +218,10 @@ static struct pasid_entry *intel_pasid_get_entry(struc= t device *dev, u32 pasid) free_pgtable_page(entries); goto retry; } + if (!ecap_coherent(info->iommu->ecap)) { + clflush_cache_range(entries, VTD_PAGE_SIZE); + clflush_cache_range(&dir[dir_index].val, sizeof(*dir)); + } } =20 return &entries[index]; --=20 2.25.1