From nobody Sat Mar 15 06:33:28 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 B3FD9C4332F for ; Thu, 9 Nov 2023 11:59:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234636AbjKIL7a (ORCPT ); Thu, 9 Nov 2023 06:59:30 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47652 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234554AbjKIL7G (ORCPT ); Thu, 9 Nov 2023 06:59:06 -0500 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.8]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 090C435A5; Thu, 9 Nov 2023 03:58:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1699531108; x=1731067108; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=dMT+cVNkz5s3pqtS4rilxjvJDXZQPHh7uYPdNVf2Njg=; b=KuZBZaMn9IofNbX5ccsxoeiIr5FB1VGqDKVMqO/CbPiMqPLvHWQqmXAT hv7JGkRrJ21iZg39rjexzG+vktdJvQTktwxo2JtLq45MDHwqMx82Z4TJB mqqWbWuSRu5CNB3zW5nLT55OKlAHAnOspnArTtOrV3IPAOoe+ttKJz0Y/ czfL6nSoclfn++xXfY/1uBRLpZWXT9Quj+9WCfXfiMsutLZGSgJbd8i6H KJo8jjio5Na0hsa5lzBvigTX6T7udQ1hTljtGIU2RqcMWWxkWm303c/6g A7x49dh4qYXHsdaKiYu7FYCFptt95iYVNh1/X0aeBu6DgHvSjVBYjDUgo Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10888"; a="2936781" X-IronPort-AV: E=Sophos;i="6.03,289,1694761200"; d="scan'208";a="2936781" Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by fmvoesa102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Nov 2023 03:58:28 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10888"; a="766977056" X-IronPort-AV: E=Sophos;i="6.03,289,1694761200"; d="scan'208";a="766977056" Received: from shadphix-mobl.amr.corp.intel.com (HELO khuang2-desk.gar.corp.intel.com) ([10.209.83.35]) by fmsmga007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Nov 2023 03:58:21 -0800 From: Kai Huang To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: x86@kernel.org, dave.hansen@intel.com, kirill.shutemov@linux.intel.com, peterz@infradead.org, tony.luck@intel.com, tglx@linutronix.de, bp@alien8.de, mingo@redhat.com, hpa@zytor.com, seanjc@google.com, pbonzini@redhat.com, rafael@kernel.org, david@redhat.com, dan.j.williams@intel.com, len.brown@intel.com, ak@linux.intel.com, isaku.yamahata@intel.com, ying.huang@intel.com, chao.gao@intel.com, sathyanarayanan.kuppuswamy@linux.intel.com, nik.borisov@suse.com, bagasdotme@gmail.com, sagis@google.com, imammedo@redhat.com, kai.huang@intel.com Subject: [PATCH v15 21/23] x86/virt/tdx: Handle TDX interaction with ACPI S3 and deeper states Date: Fri, 10 Nov 2023 00:55:58 +1300 Message-ID: X-Mailer: git-send-email 2.41.0 In-Reply-To: References: 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" TDX cannot survive from S3 and deeper states. The hardware resets and disables TDX completely when platform goes to S3 and deeper. Both TDX guests and the TDX module get destroyed permanently. The kernel uses S3 to support suspend-to-ram, and S4 or deeper states to support hibernation. The kernel also maintains TDX states to track whether it has been initialized and its metadata resource, etc. After resuming from S3 or hibernation, these TDX states won't be correct anymore. Theoretically, the kernel can do more complicated things like resetting TDX internal states and TDX module metadata before going to S3 or deeper, and re-initialize TDX module after resuming, etc, but there is no way to save/restore TDX guests for now. Until TDX supports full save and restore of TDX guests, there is no big value to handle TDX module in suspend and hibernation alone. To make things simple, just choose to make TDX mutually exclusive with S3 and hibernation. Note the TDX module is initialized at runtime. To avoid having to deal with the fuss of determining TDX state at runtime, just choose TDX vs S3 and hibernation at kernel early boot. It's a bad user experience if the choice of TDX and S3/hibernation is done at runtime anyway, i.e., the user can experience being able to do S3/hibernation but later becoming unable to due to TDX being enabled. Disable TDX in kernel early boot when hibernation support is available. Currently there's no mechanism exposed by the hibernation code to allow other kernel code to disable hibernation once for all. Disable ACPI S3 when TDX is enabled by the BIOS. For now the user needs to disable TDX in the BIOS to use ACPI S3. A new kernel command line can be added in the future if there's a need to let user disable TDX host via kernel command line. Alternatively, the kernel could disable TDX when ACPI S3 is supported and request the user to disable S3 to use TDX. But there's no existing kernel command line to do that, and BIOS doesn't always have an option to disable S3. Signed-off-by: Kai Huang Reviewed-by: Kirill A. Shutemov --- v14 -> v15: - Simplify the error message when hibernation_available() returns true by removing "Use 'nohibernate' kernel command line part". Instead, explain how to resolve in the Documentation patch. (Rafael) - Simplify the comment around hibernation_available(). (Rafael) - Also guide acpi_suspend_lowlevel with CONFIG_SUSPEND. v13 -> v14: - New patch --- arch/x86/virt/vmx/tdx/tdx.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c index 53a87034ad59..cc21a0f25bee 100644 --- a/arch/x86/virt/vmx/tdx/tdx.c +++ b/arch/x86/virt/vmx/tdx/tdx.c @@ -26,6 +26,8 @@ #include #include #include +#include +#include #include #include #include @@ -1402,6 +1404,15 @@ static int __init tdx_init(void) return -ENODEV; } =20 + /* + * At this point, hibernation_available() indicates whether or + * not hibernation support has been permanently disabled. + */ + if (hibernation_available()) { + pr_err("initialization failed: Hibernation support is enabled\n"); + return -ENODEV; + } + err =3D register_memory_notifier(&tdx_memory_nb); if (err) { pr_err("initialization failed: register_memory_notifier() failed (%d)\n", @@ -1417,6 +1428,11 @@ static int __init tdx_init(void) return -ENODEV; } =20 +#if defined(CONFIG_ACPI) && defined(CONFIG_SUSPEND) + pr_info("Disable ACPI S3. Turn off TDX in the BIOS to use ACPI S3.\n"); + acpi_suspend_lowlevel =3D NULL; +#endif + /* * Just use the first TDX KeyID as the 'global KeyID' and * leave the rest for TDX guests. --=20 2.41.0