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=-3.9 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,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 209D5C388F9 for ; Tue, 27 Oct 2020 11:26:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7F1B022265 for ; Tue, 27 Oct 2020 11:26:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="q3qzXDPy" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S460323AbgJ0L0k (ORCPT ); Tue, 27 Oct 2020 07:26:40 -0400 Received: from mail.skyhub.de ([5.9.137.197]:53410 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S460314AbgJ0L0j (ORCPT ); Tue, 27 Oct 2020 07:26:39 -0400 Received: from zn.tnic (p200300ec2f0dae00ea24eb74b2fb7b68.dip0.t-ipconnect.de [IPv6:2003:ec:2f0d:ae00:ea24:eb74:b2fb:7b68]) (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 A67AE1EC025D; Tue, 27 Oct 2020 12:26:38 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1603797998; 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=ef6LYmbq9FJher6dg4RpLI0Ys/mS9KqfkzUSj4o9KXc=; b=q3qzXDPyaUj0JIal3lSgXmgnov9BoNEmhBXfGov5q9D1Nl0Xf7jeUmSveq99RYk9CR9/bM TsnK0FbPUEA/TAqAgdKKy6njwGyRROhPZj6fEVlsAWVtowp9PbcemGMpIanKIaf0+qQaAu 7/rlI1/WSfC4yW76NCg8iitJcF0O7LQ= Date: Tue, 27 Oct 2020 12:26:35 +0100 From: Borislav Petkov To: Joerg Roedel Cc: x86@kernel.org, Joerg Roedel , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Kees Cook , Arvind Sankar , Martin Radev , Tom Lendacky , linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 5/5] x86/sev-es: Do not support MMIO to/from encrypted memory Message-ID: <20201027112635.GF15580@zn.tnic> References: <20201021123938.3696-1-joro@8bytes.org> <20201021123938.3696-6-joro@8bytes.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20201021123938.3696-6-joro@8bytes.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Oct 21, 2020 at 02:39:38PM +0200, Joerg Roedel wrote: > From: Joerg Roedel > > MMIO memory is usually not mapped encrypted, so there is no reason to > support emulated MMIO when it is mapped encrypted. > > This prevents a possible hypervisor attack where it maps a RAM page as "Prevent... " > an MMIO page in the nested page-table, so that any guest access to it > will trigger a #VC exception and leak the data on that page to the ^ "... via the GHCB (like with normal MMIO)... " Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette