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=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 4CAACC433DF for ; Fri, 3 Jul 2020 22:31:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 276E22192A for ; Fri, 3 Jul 2020 22:31:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="UxWfa4HS"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="bvB//3vc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726766AbgGCWbE (ORCPT ); Fri, 3 Jul 2020 18:31:04 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:35838 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726188AbgGCWbD (ORCPT ); Fri, 3 Jul 2020 18:31:03 -0400 From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1593815461; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=e6HM5KalB3cdRfA4Hps7INNFh9eeE6yz+RhORK/ferw=; b=UxWfa4HS6S7NQAyS/jMl4fjxbcCv1prvRSCKbsDllp1+dzc5z4T7inYWBkJ3FhkaGfHaTZ vAGLgP5gEjwFC1sgShElbTjfY3RehAdz/I6E1I+msYo1HdhV615kK2pihe8pCXeOFCgX9E WONDkzZJl/h8MJnEGa00LKFRZ09tDewa4sRXfvLgaYEAaDe0ATeTslGCTtHWH9CNJoVLkl 62KdtDowVoLPx/rBXkQleegbyC+nJxPWzpcyu6WdZgfHKU6pXPFzpUBtldeZBQuvTSrj0p EV6miUZEF3v9PMDvUvKVJnZHJUh9rLNxNz7hdtwPUXED6ouA+tE72u89gRISxw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1593815461; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=e6HM5KalB3cdRfA4Hps7INNFh9eeE6yz+RhORK/ferw=; b=bvB//3vcFyKBqGU4jVbTlAhUCfJaMSN/jkN+tpi1wI9XzIYrvfyn0Bmgf8ATogOTaNPtl2 DSyT7KFiHbveqTBg== To: Andrew Cooper , Andy Lutomirski , xen-devel , LKML , Juergen Gross , Jan Beulich , Boris Ostrovsky Cc: X86 ML Subject: Re: FSGSBASE seems to be busted on Xen PV In-Reply-To: References: Date: Sat, 04 Jul 2020 00:31:00 +0200 Message-ID: <87eepss02j.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Andrew Cooper writes: > On 03/07/2020 18:10, Andy Lutomirski wrote: >> If you can't get this fixed in upstream Xen reasonably quickly, we may >> need to disable FSGSBASE in a Xen PV guest in Linux. > > This has come up several times before, but if its actually breaking > userspace then Xen needs to change. > > I'll see about making something which is rather more robust. You mean disabling XEN PV completely? That would be indeed very robust and allows us to get rid of lots of obscure code. Feel free to add my Acked-by :) Thanks, tglx