From patchwork Wed Jun 22 11:15:57 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Huang, Kai" X-Patchwork-Id: 12890547 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 5359DC433EF for ; Wed, 22 Jun 2022 11:16:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1357093AbiFVLQM (ORCPT ); Wed, 22 Jun 2022 07:16:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55554 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1357117AbiFVLQJ (ORCPT ); Wed, 22 Jun 2022 07:16:09 -0400 Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 29C253BFBC; Wed, 22 Jun 2022 04:16:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1655896567; x=1687432567; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=658/EnJQy8x9AQuuVjfquxiCjCcnIIMedjflGOBbyXE=; b=C6wJ7lMBNa4CT0Gv0OB7XvBTPdXfwC9lwL13uH7nWvzZYfqrmAJbvgeE xrR6kUVLDSqlZIXiYqo7VxSwOJsO22VQQDdIDZJ2gAZAm0SM0MrfhGx2W zZSQsm7iHI2D7PuvrpBXk9vWk/yElettgvYHAz7xYd82+uj+q9l+m6Wnl 7fN5GUnvEyBboKV1aIx7C8hhC03yEdkuFZczDQoedR++Uoc7T/EsVd0bc vZozT2dL/gqZWJR42Tku4ISOsSDQqsBh7rWQ8Uzz67uu7ndiK99UVxuDu 6zvqAP2+t6n8ELSS+NCKf7d2d3Ku0oA5xtT3g5chy3+5NafPodNaqWdIX A==; X-IronPort-AV: E=McAfee;i="6400,9594,10385"; a="277937027" X-IronPort-AV: E=Sophos;i="5.92,212,1650956400"; d="scan'208";a="277937027" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Jun 2022 04:16:06 -0700 X-IronPort-AV: E=Sophos;i="5.92,212,1650956400"; d="scan'208";a="834065539" Received: from jmatsis-mobl.amr.corp.intel.com (HELO khuang2-desk.gar.corp.intel.com) ([10.209.178.197]) by fmsmga006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Jun 2022 04:16:03 -0700 From: Kai Huang To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: linux-acpi@vger.kernel.org, seanjc@google.com, pbonzini@redhat.com, dave.hansen@intel.com, len.brown@intel.com, tony.luck@intel.com, rafael.j.wysocki@intel.com, reinette.chatre@intel.com, dan.j.williams@intel.com, peterz@infradead.org, ak@linux.intel.com, kirill.shutemov@linux.intel.com, sathyanarayanan.kuppuswamy@linux.intel.com, isaku.yamahata@intel.com, thomas.lendacky@amd.com, kai.huang@intel.com Subject: [PATCH v5 03/22] cc_platform: Add new attribute to prevent ACPI memory hotplug Date: Wed, 22 Jun 2022 23:15:57 +1200 Message-Id: <87dc19c47bad73509359c8e1e3a81d51d1681e4c.1655894131.git.kai.huang@intel.com> X-Mailer: git-send-email 2.36.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org Platforms with confidential computing technology may not support ACPI memory hotplug when such technology is enabled by the BIOS. Examples include Intel platforms which support Intel Trust Domain Extensions (TDX). If the kernel ever receives ACPI memory hotplug event, it is likely a BIOS bug. For ACPI memory hot-add, the kernel should speak out this is a BIOS bug and reject the new memory. For hot-removal, for simplicity just assume the kernel cannot continue to work normally, and just BUG(). Add a new attribute CC_ATTR_ACPI_MEMORY_HOTPLUG_DISABLED to indicate the platform doesn't support ACPI memory hotplug, so that kernel can handle ACPI memory hotplug events for such platform. In acpi_memory_device_{add|remove}(), add early check against this attribute and handle accordingly if it is set. Signed-off-by: Kai Huang --- drivers/acpi/acpi_memhotplug.c | 23 +++++++++++++++++++++++ include/linux/cc_platform.h | 10 ++++++++++ 2 files changed, 33 insertions(+) diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c index 24f662d8bd39..94d6354ea453 100644 --- a/drivers/acpi/acpi_memhotplug.c +++ b/drivers/acpi/acpi_memhotplug.c @@ -15,6 +15,7 @@ #include #include #include +#include #include "internal.h" @@ -291,6 +292,17 @@ static int acpi_memory_device_add(struct acpi_device *device, if (!device) return -EINVAL; + /* + * If the confidential computing platform doesn't support ACPI + * memory hotplug, the BIOS should never deliver such event to + * the kernel. Report ACPI CPU hot-add as a BIOS bug and ignore + * the memory device. + */ + if (cc_platform_has(CC_ATTR_ACPI_MEMORY_HOTPLUG_DISABLED)) { + dev_err(&device->dev, "[BIOS bug]: Platform doesn't support ACPI memory hotplug. New memory device ignored.\n"); + return -EINVAL; + } + mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL); if (!mem_device) return -ENOMEM; @@ -334,6 +346,17 @@ static void acpi_memory_device_remove(struct acpi_device *device) if (!device || !acpi_driver_data(device)) return; + /* + * The confidential computing platform is broken if ACPI memory + * hot-removal isn't supported but it happened anyway. Assume + * it is not guaranteed that the kernel can continue to work + * normally. Just BUG(). + */ + if (cc_platform_has(CC_ATTR_ACPI_CPU_HOTPLUG_DISABLED)) { + dev_err(&device->dev, "Platform doesn't support ACPI memory hotplug. BUG().\n"); + BUG(); + } + mem_device = acpi_driver_data(device); acpi_memory_remove_memory(mem_device); acpi_memory_device_free(mem_device); diff --git a/include/linux/cc_platform.h b/include/linux/cc_platform.h index 9ce9256facc8..b831c24bd7f6 100644 --- a/include/linux/cc_platform.h +++ b/include/linux/cc_platform.h @@ -93,6 +93,16 @@ enum cc_attr { * Examples include TDX platform. */ CC_ATTR_ACPI_CPU_HOTPLUG_DISABLED, + + /** + * @CC_ATTR_ACPI_MEMORY_HOTPLUG_DISABLED: ACPI memory hotplug is + * not supported. + * + * The platform/os does not support ACPI memory hotplug. + * + * Examples include TDX platform. + */ + CC_ATTR_ACPI_MEMORY_HOTPLUG_DISABLED, }; #ifdef CONFIG_ARCH_HAS_CC_PLATFORM