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 D0C40C433ED for ; Thu, 8 Apr 2021 08:17:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 989266113D for ; Thu, 8 Apr 2021 08:17:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229820AbhDHIRx (ORCPT ); Thu, 8 Apr 2021 04:17:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54704 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229566AbhDHIRw (ORCPT ); Thu, 8 Apr 2021 04:17:52 -0400 Received: from mail.skyhub.de (mail.skyhub.de [IPv6:2a01:4f8:190:11c2::b:1457]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8EDBFC061760; Thu, 8 Apr 2021 01:17:41 -0700 (PDT) Received: from zn.tnic (p200300ec2f095000d1c5cef8b4104033.dip0.t-ipconnect.de [IPv6:2003:ec:2f09:5000:d1c5:cef8:b410:4033]) (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 F17F71EC027D; Thu, 8 Apr 2021 10:17:39 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1617869860; 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=hFlLhXCwCKYT4yY3v85LDEYvANk/g2ETWMLwyVoq7x8=; b=L7EMzURMHopNG1JZ4WjphuwjMHQdEiMYD1AflIaSEWIieJC564aYKAzgqqPMy3r67ZzPe5 Uz/GHbkNazFEitPiP0BZEBb/tNiTvKsZK4O+STaH7NkDscBi/KlDXVZlsg5ah5YJhNg2f7 Q094Ghb+7vEdoW0zKDGeTToe1PFdeYc= Date: Thu, 8 Apr 2021 10:17:40 +0200 From: Borislav Petkov To: Brijesh Singh Cc: linux-kernel@vger.kernel.org, x86@kernel.org, kvm@vger.kernel.org, ak@linux.intel.com, Thomas Gleixner , Ingo Molnar , Joerg Roedel , "H. Peter Anvin" , Tony Luck , Dave Hansen , "Peter Zijlstra (Intel)" , Paolo Bonzini , Tom Lendacky , David Rientjes , Sean Christopherson Subject: Re: [RFC Part1 PATCH 07/13] x86/compressed: register GHCB memory when SNP is active Message-ID: <20210408081740.GA10192@zn.tnic> References: <20210324164424.28124-1-brijesh.singh@amd.com> <20210324164424.28124-8-brijesh.singh@amd.com> <20210407115959.GC25319@zn.tnic> <2453bacb-dce3-a9c2-f506-7dae7796ab7e@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <2453bacb-dce3-a9c2-f506-7dae7796ab7e@amd.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 07, 2021 at 12:34:59PM -0500, Brijesh Singh wrote: > The feature is part of the GHCB version 2 and is enforced by the > hypervisor. I guess it can be extended for the ES. Since this feature > was not available in GHCB version 1 (base ES) so it should be presented > as an optional for the ES ? Yeah, it probably is not worth the effort. If an attacker controls the guest kernel, then it can re-register a new GHCB so it doesn't really matter. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette