From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.20]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 74E3B23ABB9 for ; Sun, 21 Jun 2026 01:53:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.20 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782006822; cv=none; b=ErtgR8eX2N2e+ElLunxdW/n7hfabliIr/psQhJNKuYeOaLQUWPORWipqHq/1GBbxbimnSUKbt125IQ7qMiwPDdEe3yh88nWD59zW24z7uRnW/IxS1eVqNpp3pkWhtNhOSA5o45PsVCdwUjee2c9QlGgzCO975yPvDCUK9asRXmk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782006822; c=relaxed/simple; bh=0IdytbMR6TeppsD+FYqGVCZHan6NncQo+OpSjxk8I4A=; h=Message-ID:Date:MIME-Version:Cc:Subject:To:References:From: In-Reply-To:Content-Type; b=Ts+EbZ7tRKFmZH/9k4cSqjYBn+Kd/aOlUfHnuiL3idk01ElszCNGvqyujNG8FJIaSn5spgpXVGCl7/RpwIXSuqFMO3uqKvO3ZbVohhR7VirhfXg4r07DstdBi6S1u9YbusT/NBC7+vQlw+Z/tuMArsBh8UaDT7bAW0dzrK3DLto= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=KCeZ9Nl6; arc=none smtp.client-ip=198.175.65.20 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="KCeZ9Nl6" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1782006822; x=1813542822; h=message-id:date:mime-version:cc:subject:to:references: from:in-reply-to:content-transfer-encoding; bh=0IdytbMR6TeppsD+FYqGVCZHan6NncQo+OpSjxk8I4A=; b=KCeZ9Nl63NSMIYMIHKYXCM7Ls9BtFdqqI1vupU0C8fRPCuijwEgBUDFC CLn0X0Jg69MtSeuDntKnSjZ9ODri8VA47F1s3Rkn2PPN9bsH+G+VAz4U2 5uwhMOahKyJi0oJk/6mquLdKBJ6riGqqBND+W5FAXtagZ34BR0cyoohU3 VZ41LJWL1hDdItuyyZXtkh9ptRZivFtyBUmUjXzOlQaaEYOpet6BJcClF 5Z0OBKUrnb/7/kdIZmvgx1w5kIKipfM4eXmiZuo0RkPhwTJndGpXAPb3Z vJuIlvL/9+7E3fd9+4cSfMSGqucs78ZUGVeMXZTOKcfcoZ/LbCJcIeqQc w==; X-CSE-ConnectionGUID: wja0HhvTS5OZxLilG06B9A== X-CSE-MsgGUID: ldgKBTwARrOFIMGHigWT3Q== X-IronPort-AV: E=McAfee;i="6800,10657,11823"; a="82556315" X-IronPort-AV: E=Sophos;i="6.24,216,1774335600"; d="scan'208";a="82556315" Received: from fmviesa004.fm.intel.com ([10.60.135.144]) by orvoesa112.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Jun 2026 18:53:41 -0700 X-CSE-ConnectionGUID: 6u0UB0TbQyq5DxD3eFw+QA== X-CSE-MsgGUID: FxUDobN6RDifAvLqSfvaDA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.24,216,1774335600"; d="scan'208";a="250831584" Received: from unknown (HELO [10.238.9.114]) ([10.238.9.114]) by fmviesa004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Jun 2026 18:53:37 -0700 Message-ID: <25bfc4b7-ec84-41f9-a68c-5dda7839320d@linux.intel.com> Date: Sun, 21 Jun 2026 09:53:36 +0800 Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Cc: baolu.lu@linux.intel.com, Joerg Roedel , Mika Westerberg , Ashok Raj , Chris Wright , Jesse Barnes , "Mallick, Asit K" , "iommu@lists.linux.dev" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 6/9] iommu/vt-d: Call dmar_can_force_on() for tboot optin To: "Tian, Kevin" , Joerg Roedel , Will Deacon , Robin Murphy References: <20260604051540.592925-1-kevin.tian@intel.com> <20260604051540.592925-7-kevin.tian@intel.com> Content-Language: en-US From: Baolu Lu In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 6/17/2026 3:19 PM, Tian, Kevin wrote: >> From: Baolu Lu >> Sent: Friday, June 12, 2026 9:58 PM >> >> On 6/4/2026 1:15 PM, Kevin Tian wrote: >>> >>> static __init int tboot_force_iommu(void) >>> { >>> - if (!tboot_enabled()) >>> + if (!tboot_enabled() || intel_iommu_tboot_noforce) >> >> Hmm, it looks a bit strange here. The core design philosophy is that the >> trusted boot environment takes priority over user options. However, > > user options here refer to "iommu=off" or "intel_iommu=off" which > opts to enable/disable iommu. > >> checking intel_iommu_tboot_noforce at the very top means a user >> option (intel_iommu=tboot_noforce) is successfully overriding tboot. > > but tboot_noforce is to specify the forceon policy on tboot. No conflict. > >> >> Is this an exception? If so, it might be worth adding a brief comment >> clarifying why `tboot_noforce` is allowed to bypass the priority? > > so this is irrelevant to the enable/disable priority part. Okay, that explains. The "intel_iommu=tboot_noforce" option is used to disable tboot entirely, which is not part of the enable/disable override. I suppose tboot_noforce is only designed for debugging purposes, so it should not be used in a production environment. Thanks, baolu