Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1752739AbeADTAS (ORCPT <rfc822;ralf@linux-mips.org> + 1 other);
        Thu, 4 Jan 2018 14:00:18 -0500
Received: from mail-io0-f181.google.com ([209.85.223.181]:40833 "EHLO
        mail-io0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1752496AbeADTAQ (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Thu, 4 Jan 2018 14:00:16 -0500
X-Google-Smtp-Source: ACJfBovRtzokjPXn0Pw55BbRiTf1GTo1EGGugeoA/Nue+ZzaKbLoEdImgYUnS7WoG1x1g26R4xmYCjwWIqRXQSkwOfI=
MIME-Version: 1.0
In-Reply-To: <cover.1515086770.git.tim.c.chen@linux.intel.com>
References: <cover.1515086770.git.tim.c.chen@linux.intel.com>
From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Thu, 4 Jan 2018 11:00:14 -0800
X-Google-Sender-Auth: iXIA-O4p_Hga_WungprzYG-Etxk
Message-ID: <CA+55aFx+5dUyKRjXEavnxzfXbiQnrmiSCw3PgPtSb+6OP-Qhcg@mail.gmail.com>
Subject: Re: [PATCH 0/7] IBRS patch series
To: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
        Andy Lutomirski <luto@kernel.org>,
        Greg KH <gregkh@linuxfoundation.org>,
        Dave Hansen <dave.hansen@intel.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Andi Kleen <ak@linux.intel.com>,
        Arjan Van De Ven <arjan.van.de.ven@intel.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
Return-Path: <linux-kernel-owner@vger.kernel.org>

On Thu, Jan 4, 2018 at 9:56 AM, Tim Chen <tim.c.chen@linux.intel.com> wrote:
>
> Speculation on Skylake and later requires these patches ("dynamic IBRS")
> be used instead of retpoline[1].

Can somebody explain this part?

I was assuming that retpoline would work around this issue on all uarchs.

This seems to say "retpoline does nothing on Skylake+"

              Linus