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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B37D4C433F5 for ; Tue, 5 Oct 2021 23:06:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9B67F611C5 for ; Tue, 5 Oct 2021 23:06:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237041AbhJEXIU (ORCPT ); Tue, 5 Oct 2021 19:08:20 -0400 Received: from mga12.intel.com ([192.55.52.136]:14166 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237005AbhJEXIH (ORCPT ); Tue, 5 Oct 2021 19:08:07 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10128"; a="205998523" X-IronPort-AV: E=Sophos;i="5.85,350,1624345200"; d="scan'208";a="205998523" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Oct 2021 16:06:16 -0700 X-IronPort-AV: E=Sophos;i="5.85,350,1624345200"; d="scan'208";a="438908013" Received: from alyee-mobl.amr.corp.intel.com (HELO skuppusw-desk1.amr.corp.intel.com) ([10.254.5.222]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Oct 2021 16:06:15 -0700 From: Kuppuswamy Sathyanarayanan To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, Paolo Bonzini , David Hildenbrand , Andrea Arcangeli , Josh Poimboeuf , "H . Peter Anvin" Cc: Dave Hansen , Tony Luck , Dan Williams , Andi Kleen , Kirill Shutemov , Sean Christopherson , Kuppuswamy Sathyanarayanan , Kuppuswamy Sathyanarayanan , linux-kernel@vger.kernel.org Subject: [PATCH v7 3/6] x86/topology: Disable CPU online/offline control for TDX guest Date: Tue, 5 Oct 2021 16:05:47 -0700 Message-Id: <20211005230550.1819406-4-sathyanarayanan.kuppuswamy@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20211005230550.1819406-1-sathyanarayanan.kuppuswamy@linux.intel.com> References: <20211005230550.1819406-1-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 titled "AP initialization in OS" (index 4.3.5) and sec titled "Hotplug Device" (index 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 v6: * None arch/x86/kernel/tdx.c | 16 ++++++++++++++++ arch/x86/kernel/topology.c | 3 ++- 2 files changed, 18 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/tdx.c b/arch/x86/kernel/tdx.c index a66520405109..203deb57c4c9 100644 --- a/arch/x86/kernel/tdx.c +++ b/arch/x86/kernel/tdx.c @@ -4,6 +4,8 @@ #undef pr_fmt #define pr_fmt(fmt) "tdx: " fmt +#include + #include #include #include @@ -307,6 +309,17 @@ static int tdx_handle_mmio(struct pt_regs *regs, struct ve_info *ve) return insn.length; } +static int tdx_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 tdx_get_ve_info(struct ve_info *ve) { struct tdx_module_output out = {0}; @@ -451,5 +464,8 @@ void __init tdx_early_init(void) pv_ops.irq.safe_halt = tdx_safe_halt; pv_ops.irq.halt = tdx_halt; + cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "tdx:cpu_hotplug", + NULL, tdx_cpu_offline_prepare); + pr_info("Guest initialized\n"); } diff --git a/arch/x86/kernel/topology.c b/arch/x86/kernel/topology.c index bd83748e2bde..ded34eda5bac 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) && !cc_platform_has(CC_ATTR_GUEST_TDX)) per_cpu(cpu_devices, num).cpu.hotpluggable = 1; return register_cpu(&per_cpu(cpu_devices, num).cpu, num); -- 2.25.1