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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 96B32C433E1 for ; Tue, 19 May 2020 09:15:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 643B2206D4 for ; Tue, 19 May 2020 09:15:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="UCHDF2Zg" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728502AbgESJPg (ORCPT ); Tue, 19 May 2020 05:15:36 -0400 Received: from mail.skyhub.de ([5.9.137.197]:57080 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726818AbgESJPg (ORCPT ); Tue, 19 May 2020 05:15:36 -0400 Received: from zn.tnic (p200300ec2f0b87003113f65f16dcf690.dip0.t-ipconnect.de [IPv6:2003:ec:2f0b:8700:3113:f65f:16dc:f690]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 99A811EC0322; Tue, 19 May 2020 11:15:34 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1589879734; 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: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=3zIW0mscrSzBoJoj+N7Op6mZu6eLSey92yt+pTI7244=; b=UCHDF2ZgyRLRTP7XNdnuIZv4h2qPUWVp7D7heCzAdEWdt15yHiKvQO71Kib2dI9IztD8je 0XrJlp8xpdDb5g8DZ7zW5IDgqVo7PX01g/D/UXElv00ZpVvJMc6eM9sQURxg+yMMLTb+Sd 4Qav+EDQoW5GfHKrvicE0mYg0jJJncI= Date: Tue, 19 May 2020 11:15:26 +0200 From: Borislav Petkov To: Joerg Roedel Cc: x86@kernel.org, hpa@zytor.com, Andy Lutomirski , Dave Hansen , Peter Zijlstra , Thomas Hellstrom , Jiri Slaby , Dan Williams , Tom Lendacky , Juergen Gross , Kees Cook , David Rientjes , Cfir Cohen , Erdem Aktas , Masami Hiramatsu , Mike Stunes , Joerg Roedel , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: Re: [PATCH v3 35/75] x86/head/64: Build k/head64.c with -fno-stack-protector Message-ID: <20200519091526.GB444@zn.tnic> References: <20200428151725.31091-1-joro@8bytes.org> <20200428151725.31091-36-joro@8bytes.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20200428151725.31091-36-joro@8bytes.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Tue, Apr 28, 2020 at 05:16:45PM +0200, Joerg Roedel wrote: > From: Joerg Roedel > > The code inserted by the stack protector does not work in the early > boot environment because it uses the GS segment, at least with memory > encryption enabled. Can you elaborate on why is that a problem? The stack cookie is not generated that early yet so it should be comparing %gs:40 to 0. Also, it generates the checking code here only with CONFIG_STACKPROTECTOR_STRONG=y > Make sure the early code is compiled without this feature enabled. If so, then this should be with CONFIG_AMD_MEM_ENCRYPT ifdeffery around it. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette