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,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 B5B0AC433DB for ; Sat, 27 Mar 2021 22:55:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8725261992 for ; Sat, 27 Mar 2021 22:55:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231138AbhC0Wy7 (ORCPT ); Sat, 27 Mar 2021 18:54:59 -0400 Received: from mga03.intel.com ([134.134.136.65]:51892 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230442AbhC0Wyv (ORCPT ); Sat, 27 Mar 2021 18:54:51 -0400 IronPort-SDR: +XnP62xFZ1ZskJbyJpMBKTJ473a6MYBKT/lJIfSfAGRBzhZK/9xpwSJ6YIREi86uG8w4bjnavF 0uxBiKVOpB7Q== X-IronPort-AV: E=McAfee;i="6000,8403,9936"; a="191372617" X-IronPort-AV: E=Sophos;i="5.81,284,1610438400"; d="scan'208";a="191372617" Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Mar 2021 15:54:50 -0700 IronPort-SDR: tLs+vEWBm+KU13l9rHtZuMweC2BQY8CntP+pmIr7kzddndrVxq4uZMkkb62u+90ChAj35C15tv WR5C8fGTuQVw== X-IronPort-AV: E=Sophos;i="5.81,284,1610438400"; d="scan'208";a="392673510" Received: from ovanloen-mobl.amr.corp.intel.com (HELO skuppusw-mobl5.amr.corp.intel.com) ([10.209.177.136]) by orsmga002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Mar 2021 15:54:49 -0700 From: Kuppuswamy Sathyanarayanan To: Peter Zijlstra , Andy Lutomirski , Dave Hansen Cc: Andi Kleen , Kirill Shutemov , Kuppuswamy Sathyanarayanan , Dan Williams , Raj Ashok , Sean Christopherson , linux-kernel@vger.kernel.org, Kuppuswamy Sathyanarayanan Subject: [PATCH v2 1/1] x86/tdx: Handle MWAIT, MONITOR and WBINVD Date: Sat, 27 Mar 2021 15:54:40 -0700 Message-Id: X-Mailer: git-send-email 2.25.1 In-Reply-To: <91C0F6F1-B8C3-4130-B903-C63CD4B87F3F@amacapital.net> References: <91C0F6F1-B8C3-4130-B903-C63CD4B87F3F@amacapital.net> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 v1: * Added WARN() for MWAIT #VE exception. 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..3c6158a53c17 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); + tdg_get_info(); pv_ops.irq.safe_halt = tdg_safe_halt; @@ -362,6 +365,26 @@ int tdg_handle_virtualization_exception(struct pt_regs *regs, case EXIT_REASON_EPT_VIOLATION: ve->instr_len = tdg_handle_mmio(regs, ve); break; + /* + * Per Guest-Host-Communication Interface (GHCI) for Intel Trust + * Domain Extensions (Intel TDX) specification, sec 2.4, + * some instructions that unconditionally cause #VE (such as WBINVD, + * MONITOR, MWAIT) do not have corresponding TDCALL + * [TDG.VP.VMCALL ] leaves, since the TD has been designed + * with no deterministic way to confirm the result of those operations + * performed by the host VMM. In those cases, the goal is for the TD + * #VE handler to increment the RIP appropriately based on the VE + * information provided via TDCALL. + */ + case EXIT_REASON_WBINVD: + pr_warn_once("WBINVD #VE Exception\n"); + case EXIT_REASON_MONITOR_INSTRUCTION: + /* Handle as nops. */ + break; + case EXIT_REASON_MWAIT_INSTRUCTION: + /* MWAIT is supressed, not supposed to reach here. */ + WARN(1, "MWAIT unexpected #VE Exception\n"); + return -EFAULT; default: pr_warn("Unexpected #VE: %d\n", ve->exit_reason); return -EFAULT; -- 2.25.1