From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 823AFC4338F for ; Wed, 4 Aug 2021 19:28:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6C6D060F58 for ; Wed, 4 Aug 2021 19:28:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240783AbhHDT2N (ORCPT ); Wed, 4 Aug 2021 15:28:13 -0400 Received: from mga01.intel.com ([192.55.52.88]:42526 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231281AbhHDT2C (ORCPT ); Wed, 4 Aug 2021 15:28:02 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10066"; a="235953239" X-IronPort-AV: E=Sophos;i="5.84,295,1620716400"; d="scan'208";a="235953239" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Aug 2021 12:27:49 -0700 X-IronPort-AV: E=Sophos;i="5.84,295,1620716400"; d="scan'208";a="585563757" Received: from mjkendri-mobl.amr.corp.intel.com (HELO skuppusw-desk1.amr.corp.intel.com) ([10.254.17.117]) by fmsmga001-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Aug 2021 12:27:48 -0700 From: Kuppuswamy Sathyanarayanan To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Peter Zijlstra , Andy Lutomirski Cc: Peter H Anvin , Dave Hansen , Tony Luck , Dan Williams , Andi Kleen , Kirill Shutemov , Sean Christopherson , Kuppuswamy Sathyanarayanan , x86@kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v4 3/5] x86/topology: Disable CPU online/offline control for TDX guest Date: Wed, 4 Aug 2021 12:27:26 -0700 Message-Id: <20210804192729.2902472-4-sathyanarayanan.kuppuswamy@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210804192729.2902472-1-sathyanarayanan.kuppuswamy@linux.intel.com> References: <20210804192729.2902472-1-sathyanarayanan.kuppuswamy@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org As per Intel TDX Virtual Firmware Design Guide, sec 4.3.5 and sec 9.4, all unused CPUs are put in spinning state by TDVF until OS requests for CPU bring-up via mailbox address passed by ACPI MADT table. Since by default all unused CPUs are always in spinning state, there is no point in supporting dynamic CPU online/offline feature. So current generation of TDVF does not support CPU hotplug feature. It may be supported in next generation. Signed-off-by: Kuppuswamy Sathyanarayanan Reviewed-by: Andi Kleen Reviewed-by: Tony Luck --- Changes since v3: * Rebased on top of Tom Lendacky's protected guest change. Changes since v1: * Replaced is_tdx_guest() check with prot_guest_has(PR_GUEST_TDX). arch/x86/kernel/tdx.c | 15 +++++++++++++++ arch/x86/kernel/topology.c | 3 ++- 2 files changed, 17 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/tdx.c b/arch/x86/kernel/tdx.c index 4080f7546e62..1b6ed482c6b6 100644 --- a/arch/x86/kernel/tdx.c +++ b/arch/x86/kernel/tdx.c @@ -5,6 +5,7 @@ #define pr_fmt(fmt) "x86/tdx: " fmt #include +#include #include #include @@ -303,6 +304,17 @@ static int tdg_handle_mmio(struct pt_regs *regs, struct ve_info *ve) return insn.length; } +static int tdg_cpu_offline_prepare(unsigned int cpu) +{ + /* + * Per Intel TDX Virtual Firmware Design Guide, + * sec 4.3.5 and sec 9.4, Hotplug is not supported + * in TDX platforms. So don't support CPU + * offline feature once it is turned on. + */ + return -EOPNOTSUPP; +} + unsigned long tdg_get_ve_info(struct ve_info *ve) { u64 ret; @@ -443,5 +455,8 @@ void __init tdx_early_init(void) pv_ops.irq.safe_halt = tdg_safe_halt; pv_ops.irq.halt = tdg_halt; + cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "tdg:cpu_hotplug", + NULL, tdg_cpu_offline_prepare); + pr_info("Guest initialized\n"); } diff --git a/arch/x86/kernel/topology.c b/arch/x86/kernel/topology.c index bd83748e2bde..c637f49d029a 100644 --- a/arch/x86/kernel/topology.c +++ b/arch/x86/kernel/topology.c @@ -32,6 +32,7 @@ #include #include #include +#include #include #include @@ -130,7 +131,7 @@ int arch_register_cpu(int num) } } } - if (num || cpu0_hotpluggable) + if ((num || cpu0_hotpluggable) && !prot_guest_has(PATTR_GUEST_TDX)) per_cpu(cpu_devices, num).cpu.hotpluggable = 1; return register_cpu(&per_cpu(cpu_devices, num).cpu, num); -- 2.25.1