From nobody Mon Feb 9 15:06:57 2026 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 22692C74A5B for ; Wed, 29 Mar 2023 13:47:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230025AbjC2NrS (ORCPT ); Wed, 29 Mar 2023 09:47:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49878 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229847AbjC2NrN (ORCPT ); Wed, 29 Mar 2023 09:47:13 -0400 Received: from mga06.intel.com (mga06b.intel.com [134.134.136.31]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B885BB0 for ; Wed, 29 Mar 2023 06:47:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1680097632; x=1711633632; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=3gnKgqRTKyghIyM4UgGaD9bRnVtsRIMSCRTLjmJOQmI=; b=E6gsPkDApyZV7LgiUj0bdaEU0UNmbNNEHG1TZ+lpi/Qy81cYRunRMFfY EIjeGhDuGKgre2JXosVmf8q3bi4Q02j7pSeBS5/7HkiE97ctwICiHOJMt CnCnShIXAy0HGqQ3fVMrN0a/Qnlma3o2SdCL4UDQ6b/EiCZjGPp+70L2i AF5EFSObpIWPH7iZLNMQWEIzDbU+Dq/CEk1OsHkCnrlERjWMpbWUDvPuf Z9EneGoiYefnrBBFsRe3fweh7f9bC2fZGCgZkfA0AOeE3NO1qJ0IiJ0no 92ahZWm/vuoaYPfWve3lDoHkaOr1IkWDwrSvJ8lNrRm4767xNKeWOXUMB Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10664"; a="403506240" X-IronPort-AV: E=Sophos;i="5.98,300,1673942400"; d="scan'208";a="403506240" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Mar 2023 06:47:09 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10664"; a="677783384" X-IronPort-AV: E=Sophos;i="5.98,300,1673942400"; d="scan'208";a="677783384" Received: from allen-box.sh.intel.com ([10.239.159.48]) by orsmga007.jf.intel.com with ESMTP; 29 Mar 2023 06:47:07 -0700 From: Lu Baolu To: Joerg Roedel Cc: Kan Liang , Lu Baolu , iommu@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH 2/3] iommu/vt-d: Allow zero SAGAW if second-stage not supported Date: Wed, 29 Mar 2023 21:47:20 +0800 Message-Id: <20230329134721.469447-3-baolu.lu@linux.intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230329134721.469447-1-baolu.lu@linux.intel.com> References: <20230329134721.469447-1-baolu.lu@linux.intel.com> 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" The VT-d spec states (in section 11.4.2) that hardware implementations reporting second-stage translation support (SSTS) field as Clear also report the SAGAW field as 0. Fix an inappropriate check in alloc_iommu(). Fixes: 792fb43ce2c9 ("iommu/vt-d: Enable Intel IOMMU scalable mode by defau= lt") Suggested-by: Raghunathan Srinivasan Reviewed-by: Kevin Tian Signed-off-by: Jacob Pan Signed-off-by: Lu Baolu Link: https://lore.kernel.org/r/20230318024824.124542-1-baolu.lu@linux.inte= l.com --- drivers/iommu/intel/dmar.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/intel/dmar.c b/drivers/iommu/intel/dmar.c index 6acfe879589c..23828d189c2a 100644 --- a/drivers/iommu/intel/dmar.c +++ b/drivers/iommu/intel/dmar.c @@ -1071,7 +1071,8 @@ static int alloc_iommu(struct dmar_drhd_unit *drhd) } =20 err =3D -EINVAL; - if (cap_sagaw(iommu->cap) =3D=3D 0) { + if (!cap_sagaw(iommu->cap) && + (!ecap_smts(iommu->ecap) || ecap_slts(iommu->ecap))) { pr_info("%s: No supported address widths. Not attempting DMA translation= .\n", iommu->name); drhd->ignored =3D 1; --=20 2.34.1