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,URIBL_BLOCKED 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 F3163C433E0 for ; Fri, 3 Jul 2020 22:31:39 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id BC6872192A for ; Fri, 3 Jul 2020 22:31:39 +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" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BC6872192A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linutronix.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jrUD6-0006Ke-EQ; Fri, 03 Jul 2020 22:31:08 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jrUD4-0006KZ-Db for xen-devel@lists.xenproject.org; Fri, 03 Jul 2020 22:31:07 +0000 X-Inumbo-ID: e044b874-bd7c-11ea-bca7-bc764e2007e4 Received: from galois.linutronix.de (unknown [2a0a:51c0:0:12e:550::1]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id e044b874-bd7c-11ea-bca7-bc764e2007e4; Fri, 03 Jul 2020 22:31:03 +0000 (UTC) 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 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 X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: X86 ML Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" 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