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=-14.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,HK_RANDOM_FROM,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 2C3CEC433DB for ; Tue, 30 Mar 2021 04:57:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E12A261919 for ; Tue, 30 Mar 2021 04:57:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230333AbhC3E5M (ORCPT ); Tue, 30 Mar 2021 00:57:12 -0400 Received: from mga18.intel.com ([134.134.136.126]:49193 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230280AbhC3E4q (ORCPT ); Tue, 30 Mar 2021 00:56:46 -0400 IronPort-SDR: tOxfriJYc7noS5ajTjzn0aWXb3fbmD1zpaOsEW4KLg15GAQfBTmgHEo0Fw/1bFRqeCPcYNdBdu SwLIGy4MAdEg== X-IronPort-AV: E=McAfee;i="6000,8403,9938"; a="179231599" X-IronPort-AV: E=Sophos;i="5.81,289,1610438400"; d="scan'208";a="179231599" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Mar 2021 21:56:46 -0700 IronPort-SDR: lsuIO7yps5TfrDZEGzRip6Lgqbfy7fftvVLDnbNXnCqD+Veh0/QF6Sy27gfIyskw0m2qoyZiE2 sXG9UwdqgAbg== X-IronPort-AV: E=Sophos;i="5.81,289,1610438400"; d="scan'208";a="417992474" Received: from unknown (HELO [10.239.13.106]) ([10.239.13.106]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Mar 2021 21:56:43 -0700 Subject: Re: [PATCH v1 1/1] x86/tdx: Handle MWAIT, MONITOR and WBINVD To: Kuppuswamy Sathyanarayanan , Peter Zijlstra , Andy Lutomirski , Dave Hansen Cc: Andi Kleen , Kirill Shutemov , Kuppuswamy Sathyanarayanan , Dan Williams , Raj Ashok , Sean Christopherson , linux-kernel@vger.kernel.org References: <331b34e3d6153f0a7b0ab0a9a8cb5de71f0bfd93.1616803999.git.sathyanarayanan.kuppuswamy@linux.intel.com> From: Xiaoyao Li Message-ID: Date: Tue, 30 Mar 2021 12:56:41 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.9.0 MIME-Version: 1.0 In-Reply-To: <331b34e3d6153f0a7b0ab0a9a8cb5de71f0bfd93.1616803999.git.sathyanarayanan.kuppuswamy@linux.intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/27/2021 8:18 AM, Kuppuswamy Sathyanarayanan wrote: > In non-root TDX guest mode, MWAIT, MONITOR and WBINVD instructions > are not supported. So handle #VE due to these instructions as no ops. > > Signed-off-by: Kuppuswamy Sathyanarayanan > Reviewed-by: Andi Kleen > --- > > Changes since previous series: > * Suppressed MWAIT feature as per Andi's comment. > * Added warning debug log for MWAIT #VE exception. > > arch/x86/kernel/tdx.c | 23 +++++++++++++++++++++++ > 1 file changed, 23 insertions(+) > > diff --git a/arch/x86/kernel/tdx.c b/arch/x86/kernel/tdx.c > index e936b2f88bf6..fb7d22b846fc 100644 > --- a/arch/x86/kernel/tdx.c > +++ b/arch/x86/kernel/tdx.c > @@ -308,6 +308,9 @@ void __init tdx_early_init(void) > > setup_force_cpu_cap(X86_FEATURE_TDX_GUEST); > > + /* MWAIT is not supported in TDX platform, so suppress it */ > + setup_clear_cpu_cap(X86_FEATURE_MWAIT); In fact, MWAIT bit returned by CPUID instruction is zero for TD guest. This is enforced by SEAM module. Do we still need to safeguard it by setup_clear_cpu_cap() here? > + > tdg_get_info(); > > pv_ops.irq.safe_halt = tdg_safe_halt;