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 F4020C433C1 for ; Mon, 29 Mar 2021 23:18:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C90E96188B for ; Mon, 29 Mar 2021 23:18:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229763AbhC2XRy (ORCPT ); Mon, 29 Mar 2021 19:17:54 -0400 Received: from mga09.intel.com ([134.134.136.24]:10854 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229441AbhC2XRV (ORCPT ); Mon, 29 Mar 2021 19:17:21 -0400 IronPort-SDR: NFdBpGQmtb+alLH3ZwJqkzE8lSFQiAlyuP/QJQtrQwbf+qUEZkhnoAlAy3P8YjUnC3zMEC/Z0i i0swwUBWb7Qw== X-IronPort-AV: E=McAfee;i="6000,8403,9938"; a="191743015" X-IronPort-AV: E=Sophos;i="5.81,289,1610438400"; d="scan'208";a="191743015" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Mar 2021 16:17:19 -0700 IronPort-SDR: Z5W0BMz5p8K2prWGUK0s1hxhRXMVSn9v/y8W2FVfTOvWCMp6wfu0nY2P2k38RUIchYFJLZx9vI O0477Mk34e1A== X-IronPort-AV: E=Sophos;i="5.81,289,1610438400"; d="scan'208";a="411316263" Received: from ajzangar-mobl1.amr.corp.intel.com (HELO skuppusw-mobl5.amr.corp.intel.com) ([10.212.145.70]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Mar 2021 16:17:18 -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 v3 1/1] x86/tdx: Handle MWAIT, MONITOR and WBINVD Date: Mon, 29 Mar 2021 16:16:15 -0700 Message-Id: <837afe840f5826bf7fcba07a5e483d7e2283db34.1617059703.git.sathyanarayanan.kuppuswamy@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <0356a84a-765e-b20b-2efd-c5d94fc2347e@intel.com> References: <0356a84a-765e-b20b-2efd-c5d94fc2347e@intel.com> 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 appropriately. Since the impact of executing WBINVD instruction in non ring-0 mode can be heavy, use BUG() to report it. For others, raise a WARNING message. Signed-off-by: Kuppuswamy Sathyanarayanan Reviewed-by: Andi Kleen --- Changes since v2: * Added BUG() for WBINVD, WARN for MONITOR instructions. * Fixed comments as per Dave's review. 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 | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) diff --git a/arch/x86/kernel/tdx.c b/arch/x86/kernel/tdx.c index e936b2f88bf6..4c6336a055a3 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 +365,32 @@ int tdg_handle_virtualization_exception(struct pt_regs *regs, case EXIT_REASON_EPT_VIOLATION: ve->instr_len = tdg_handle_mmio(regs, ve); break; + case EXIT_REASON_WBINVD: + /* + * WBINVD is a privileged instruction, can only be executed + * in ring 0. Since we reached here, the kernel is in buggy + * state. + */ + pr_err("WBINVD #VE Exception\n"); + BUG(); + break; + case EXIT_REASON_MONITOR_INSTRUCTION: + /* + * MONITOR is a privileged instruction, can only be executed + * in ring 0. So we are not supposed to reach here. Raise a + * warning message. + */ + WARN(1, "MONITOR unexpected #VE Exception\n"); + break; + case EXIT_REASON_MWAIT_INSTRUCTION: + /* + * MWAIT feature is suppressed in firmware and in + * tdx_early_init() by clearing X86_FEATURE_MWAIT CPU feature + * flag. Since we are not supposed to reach here, raise a + * warning message and return -EFAULT. + */ + WARN(1, "MWAIT unexpected #VE Exception\n"); + return -EFAULT; default: pr_warn("Unexpected #VE: %d\n", ve->exit_reason); return -EFAULT; -- 2.25.1