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=-7.7 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,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 2E6FAC04EBF for ; Tue, 4 Dec 2018 11:04:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E9F482087F for ; Tue, 4 Dec 2018 11:04:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="cHkXvwGt" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E9F482087F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728017AbeLDLEf (ORCPT ); Tue, 4 Dec 2018 06:04:35 -0500 Received: from mail.kernel.org ([198.145.29.99]:51650 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728003AbeLDLEd (ORCPT ); Tue, 4 Dec 2018 06:04:33 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C90E021527; Tue, 4 Dec 2018 11:04:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1543921472; bh=jYiSOXOY58QwGDh3vit4SP6BPLczW91Zgh8T3vmM7cU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cHkXvwGtegfIFahfxCvSDWLNJRKvIHHuAJciPk3bdaED7ujJCFiet9J53csWeuxSG 8G0H0kd3zyTc1H6fgkHZV/iz7E43IeqQrqxGgDQjmgLrQhyPl7pFIzlr42CanSI8v7 ZOrun0otigFgERXq8aTZkKkX3foBIJ6gSgkSk8Z0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Tim Chen , Thomas Gleixner , Ingo Molnar , Peter Zijlstra , Andy Lutomirski , Linus Torvalds , Jiri Kosina , Tom Lendacky , Josh Poimboeuf , Andrea Arcangeli , David Woodhouse , Andi Kleen , Dave Hansen , Casey Schaufler , Asit Mallick , Arjan van de Ven , Jon Masters , Waiman Long , Dave Stewart , Kees Cook Subject: [PATCH 4.14 084/146] x86/speculation: Disable STIBP when enhanced IBRS is in use Date: Tue, 4 Dec 2018 11:49:30 +0100 Message-Id: <20181204103730.206501751@linuxfoundation.org> X-Mailer: git-send-email 2.19.2 In-Reply-To: <20181204103726.750894136@linuxfoundation.org> References: <20181204103726.750894136@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tim Chen tim.c.chen@linux.intel.com commit 34bce7c9690b1d897686aac89604ba7adc365556 upstream If enhanced IBRS is active, STIBP is redundant for mitigating Spectre v2 user space exploits from hyperthread sibling. Disable STIBP when enhanced IBRS is used. Signed-off-by: Tim Chen Signed-off-by: Thomas Gleixner Reviewed-by: Ingo Molnar Cc: Peter Zijlstra Cc: Andy Lutomirski Cc: Linus Torvalds Cc: Jiri Kosina Cc: Tom Lendacky Cc: Josh Poimboeuf Cc: Andrea Arcangeli Cc: David Woodhouse Cc: Andi Kleen Cc: Dave Hansen Cc: Casey Schaufler Cc: Asit Mallick Cc: Arjan van de Ven Cc: Jon Masters Cc: Waiman Long Cc: Greg KH Cc: Dave Stewart Cc: Kees Cook Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20181125185003.966801480@linutronix.de Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/cpu/bugs.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -319,6 +319,10 @@ static bool stibp_needed(void) if (spectre_v2_enabled == SPECTRE_V2_NONE) return false; + /* Enhanced IBRS makes using STIBP unnecessary. */ + if (spectre_v2_enabled == SPECTRE_V2_IBRS_ENHANCED) + return false; + if (!boot_cpu_has(X86_FEATURE_STIBP)) return false; @@ -843,6 +847,9 @@ static ssize_t l1tf_show_state(char *buf static char *stibp_state(void) { + if (spectre_v2_enabled == SPECTRE_V2_IBRS_ENHANCED) + return ""; + if (x86_spec_ctrl_base & SPEC_CTRL_STIBP) return ", STIBP"; else