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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 87A86C4321D for ; Mon, 20 Aug 2018 16:01:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4AA9221581 for ; Mon, 20 Aug 2018 16:01:10 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4AA9221581 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linutronix.de 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 S1727274AbeHTTRU (ORCPT ); Mon, 20 Aug 2018 15:17:20 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:55896 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726667AbeHTTRU (ORCPT ); Mon, 20 Aug 2018 15:17:20 -0400 Received: from hsi-kbw-5-158-153-52.hsi19.kabel-badenwuerttemberg.de ([5.158.153.52] helo=nanos.tec.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1frmbs-0000HZ-2U; Mon, 20 Aug 2018 18:00:52 +0200 Date: Mon, 20 Aug 2018 18:00:51 +0200 (CEST) From: Thomas Gleixner To: Jim Mattson cc: Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Borislav Petkov , Konrad Rzeszutek Wilk , David Woodhouse , linux-kernel@vger.kernel.org, Fred Jacobs , Peter Shier Subject: Re: [PATCH] x86/spectre: Expand test for vulnerability to empty RSB exploits In-Reply-To: <20180807222535.143193-1-jmattson@google.com> Message-ID: References: <20180807222535.143193-1-jmattson@google.com> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 7 Aug 2018, Jim Mattson wrote: > Skylake-era Intel CPUs are vulnerable to exploits of empty RSB > conditions. On hardware, platform vulnerability can be determined > simply by checking the processor's DisplayModel/DisplayFamily > signature. However, when running in a VM, the operating system should > also query IA32_ARCH_CAPABILITIES.RSBA[bit 2], a synthetic bit that > can be set by a hypervisor to indicate that the VM might run on a > vulnerable physical processor, regardless of the > DisplayModel/DisplayFamily reported by CPUID. > > Note that IA32_ARCH_CAPABILITIES.RSBA[bit 2] is always clear on > hardware, so the DisplayModel/DisplayFamily check is still required. > > For all of the details, see the Intel white paper, "Retpoline: A > Branch Target Injection Mitigation" (document number 337131-001), > section 5.3: Virtual Machine CPU Identification. > > Signed-off-by: Jim Mattson > Reviewed-by: Peter Shier That has been superseeded by: fdf82a7856b3 ("x86/speculation: Protect against userspace-userspace spectreRSB") right? At least it does not apply anymore... Thanks, tglx