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 CBCC2C433ED for ; Mon, 26 Apr 2021 18:03:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 931E360FE5 for ; Mon, 26 Apr 2021 18:03:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234241AbhDZSEX (ORCPT ); Mon, 26 Apr 2021 14:04:23 -0400 Received: from mga05.intel.com ([192.55.52.43]:6419 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234279AbhDZSDa (ORCPT ); Mon, 26 Apr 2021 14:03:30 -0400 IronPort-SDR: x47xAY+uSnimq6jHnwkHjI32XzJoNUGqlg37wq0Wt4MN+4X65bRpUmab65YZ3pS7lDrq/phU5x +KvBpT7nft4g== X-IronPort-AV: E=McAfee;i="6200,9189,9966"; a="281710678" X-IronPort-AV: E=Sophos;i="5.82,252,1613462400"; d="scan'208";a="281710678" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Apr 2021 11:02:47 -0700 IronPort-SDR: dvcm1gFRbCpTm4A7Ju6gGo23W0T2DiLrXFXbmCghwgYPgdNa8RFg5rtYpsYDgby3kVx31Bs0WB +mlYWkXRTwPw== X-IronPort-AV: E=Sophos;i="5.82,252,1613462400"; d="scan'208";a="447353367" Received: from ssumanpx-mobl.amr.corp.intel.com (HELO skuppusw-mobl5.amr.corp.intel.com) ([10.254.34.197]) by fmsmga004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Apr 2021 11:02:44 -0700 From: Kuppuswamy Sathyanarayanan To: Peter Zijlstra , Andy Lutomirski , Dave Hansen , Dan Williams , Tony Luck Cc: Andi Kleen , Kirill Shutemov , Kuppuswamy Sathyanarayanan , Raj Ashok , Sean Christopherson , linux-kernel@vger.kernel.org, Kuppuswamy Sathyanarayanan Subject: [RFC v2 09/32] x86/tdx: Add HLT support for TDX guest Date: Mon, 26 Apr 2021 11:01:36 -0700 Message-Id: <5c11caeada56565b02ca64185be224056f3274c3.1619458733.git.sathyanarayanan.kuppuswamy@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Kirill A. Shutemov" Per Guest-Host-Communication Interface (GHCI) for Intel Trust Domain Extensions (Intel TDX) specification, sec 3.8, TDVMCALL[Instruction.HLT] provides HLT operation. Use it to implement halt() and safe_halt() paravirtualization calls. The same TDVMCALL is used to handle #VE exception due to EXIT_REASON_HLT. Signed-off-by: Kirill A. Shutemov Reviewed-by: Andi Kleen Reviewed-by: Tony Luck Signed-off-by: Kuppuswamy Sathyanarayanan --- arch/x86/kernel/tdx.c | 44 ++++++++++++++++++++++++++++++++++++------- 1 file changed, 37 insertions(+), 7 deletions(-) diff --git a/arch/x86/kernel/tdx.c b/arch/x86/kernel/tdx.c index ccfcb07bfb2c..5169f72b6b3f 100644 --- a/arch/x86/kernel/tdx.c +++ b/arch/x86/kernel/tdx.c @@ -82,6 +82,27 @@ static void tdg_get_info(void) td_info.attributes = out.rdx; } +static __cpuidle void tdg_halt(void) +{ + u64 ret; + + ret = __tdvmcall(EXIT_REASON_HLT, 0, 0, 0, 0, NULL); + + /* It should never fail */ + BUG_ON(ret); +} + +static __cpuidle void tdg_safe_halt(void) +{ + /* + * Enable interrupts next to the TDVMCALL to avoid + * performance degradation. + */ + asm volatile("sti\n\t"); + + tdg_halt(); +} + unsigned long tdg_get_ve_info(struct ve_info *ve) { u64 ret; @@ -111,13 +132,19 @@ unsigned long tdg_get_ve_info(struct ve_info *ve) int tdg_handle_virtualization_exception(struct pt_regs *regs, struct ve_info *ve) { - /* - * TODO: Add handler support for various #VE exit - * reasons. It will be added by other patches in - * the series. - */ - pr_warn("Unexpected #VE: %lld\n", ve->exit_reason); - return -EFAULT; + switch (ve->exit_reason) { + case EXIT_REASON_HLT: + tdg_halt(); + break; + default: + pr_warn("Unexpected #VE: %lld\n", ve->exit_reason); + return -EFAULT; + } + + /* After successful #VE handling, move the IP */ + regs->ip += ve->instr_len; + + return 0; } void __init tdx_early_init(void) @@ -129,5 +156,8 @@ void __init tdx_early_init(void) tdg_get_info(); + pv_ops.irq.safe_halt = tdg_safe_halt; + pv_ops.irq.halt = tdg_halt; + pr_info("TDX guest is initialized\n"); } -- 2.25.1