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=-5.8 required=3.0 tests=BAYES_00,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 0555DC4332F for ; Fri, 24 Sep 2021 09:51:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E05B1610CF for ; Fri, 24 Sep 2021 09:51:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245355AbhIXJxY (ORCPT ); Fri, 24 Sep 2021 05:53:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59056 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245320AbhIXJxY (ORCPT ); Fri, 24 Sep 2021 05:53:24 -0400 Received: from mail.skyhub.de (mail.skyhub.de [IPv6:2a01:4f8:190:11c2::b:1457]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7FCADC061574; Fri, 24 Sep 2021 02:51:51 -0700 (PDT) Received: from zn.tnic (p200300ec2f0dd600d43e805889b23e24.dip0.t-ipconnect.de [IPv6:2003:ec:2f0d:d600:d43e:8058:89b2:3e24]) (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 DC4151EC0301; Fri, 24 Sep 2021 11:51:45 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1632477106; 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=chSLn6PIxzKxo322BTSR3wKHxsK14lHDAqUJBVwt9Eo=; b=CfbAAofZ6R9ns5NFPki+7QaitPLpejuXdZJnxlWVBsvBowrNUxHEqrUKe2Y/BdplMet7fD Nq3F50WTgrfr42U+7z5YTTrv+pRjCylIw87rlK6B7Va1B8V8LlSqHAb6L8QXwsedXXkhcz 4vGmH2JazfBltplsu+R4klbu0kJ61KI= Date: Fri, 24 Sep 2021 11:51:44 +0200 From: Borislav Petkov To: Tom Lendacky Cc: "Kirill A. Shutemov" , linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, x86@kernel.org, iommu@lists.linux-foundation.org, kvm@vger.kernel.org, linux-efi@vger.kernel.org, platform-driver-x86@vger.kernel.org, linux-graphics-maintainer@vmware.com, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, kexec@lists.infradead.org, linux-fsdevel@vger.kernel.org, Brijesh Singh , Joerg Roedel , Andi Kleen , Sathyanarayanan Kuppuswamy , Tianyu Lan , Christoph Hellwig , Thomas Gleixner , Ingo Molnar , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Will Deacon Subject: Re: [PATCH v3 5/8] x86/sme: Replace occurrences of sme_active() with cc_platform_has() Message-ID: References: <20210921213401.i2pzaotgjvn4efgg@box.shutemov.name> <00f52bf8-cbc6-3721-f40e-2f51744751b0@amd.com> <20210921215830.vqxd75r4eyau6cxy@box.shutemov.name> <01891f59-7ec3-cf62-a8fc-79f79ca76587@amd.com> <20210922143015.vvxvh6ec73lffvkf@box.shutemov.name> <20210922210558.itofvu3725dap5xx@box.shutemov.name> <20210924094132.gxyqp4z3qdk5w4j6@box.shutemov.name> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20210924094132.gxyqp4z3qdk5w4j6@box.shutemov.name> Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org On Fri, Sep 24, 2021 at 12:41:32PM +0300, Kirill A. Shutemov wrote: > On Thu, Sep 23, 2021 at 08:21:03PM +0200, Borislav Petkov wrote: > > On Thu, Sep 23, 2021 at 12:05:58AM +0300, Kirill A. Shutemov wrote: > > > Unless we find other way to guarantee RIP-relative access, we must use > > > fixup_pointer() to access any global variables. > > > > Yah, I've asked compiler folks about any guarantees we have wrt > > rip-relative addresses but it doesn't look good. Worst case, we'd have > > to do the fixup_pointer() thing. > > > > In the meantime, Tom and I did some more poking at this and here's a > > diff ontop. > > > > The direction being that we'll stick both the AMD and Intel > > *cc_platform_has() call into cc_platform.c for which instrumentation > > will be disabled so no issues with that. > > > > And that will keep all that querying all together in a single file. > > And still do cc_platform_has() calls in __startup_64() codepath? > > It's broken. > > Intel detection in cc_platform_has() relies on boot_cpu_data.x86_vendor > which is not initialized until early_cpu_init() in setup_arch(). Given > that X86_VENDOR_INTEL is 0 it leads to false-positive. Yeah, Tom, I had the same question yesterday. /me looks in his direction. :-) -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette