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=-3.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT autolearn=ham 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 313ACC31680 for ; Mon, 21 Jan 2019 19:15:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EB75521019 for ; Mon, 21 Jan 2019 19:15:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548098146; bh=9fPvEs/PgoQJvwCEzm5MVBesbZMOcsYpOdVVRUXs97s=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=tGBg+EPPyOD2dSuttuX4ZJdLSG6mdsKzYSPQuYtKlzhSIs+3epT/W125dVc49xgvk wg9yxDnY5+gkVt68hinhkxiqUKw1tMCWrLa9qkndCk5os8MjhU+4eTa2LnboCjqp9/ oCLR1lS8mnS31Yx0TSq/PJOZBzZD8jhZwSwkP2JQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727855AbfAUTPo (ORCPT ); Mon, 21 Jan 2019 14:15:44 -0500 Received: from mail.kernel.org ([198.145.29.99]:39956 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726078AbfAUTPo (ORCPT ); Mon, 21 Jan 2019 14:15:44 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id DC52D2089F; Mon, 21 Jan 2019 19:15:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548098143; bh=9fPvEs/PgoQJvwCEzm5MVBesbZMOcsYpOdVVRUXs97s=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=qdkw6Sx7rdfdAlIyZsB2CHz/w77+d136iOeZGU2dm5z9uPefs+b4w1FnxqeVSdm6S z4h7/tstUMLhJ4G+ym9p36ToBYrSKRg+C5eqAZ8fdI1CzAGCVpqhDkAztuMf7dlJoO kGCWFIE6wF1Z2og9FnaqKMjonCSHQmyxQuWRyTYg= Date: Mon, 21 Jan 2019 20:15:41 +0100 From: Greg KH To: Andi Kleen Cc: Julian Stecklina , linux-kernel@vger.kernel.org, David Woodhouse , Liran Alon , Paolo Bonzini , Thomas Gleixner , Linus Torvalds , x86@kernel.org, Kernel Hardening Subject: Re: [RFC] x86/speculation: add L1 Terminal Fault / Foreshadow demo Message-ID: <20190121191541.GB4026@kroah.com> References: <1548076208-6442-1-git-send-email-jsteckli@amazon.de> <20190121183618.GP6118@tassilo.jf.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190121183618.GP6118@tassilo.jf.intel.com> User-Agent: Mutt/1.11.2 (2019-01-07) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 21, 2019 at 10:36:18AM -0800, Andi Kleen wrote: > > + /* Check the start address: needs to be page-aligned.. */ > > +- if (start & ~PAGE_MASK) > > ++ if (start & ~PAGE_MASK) { > > ++ > > ++ /* > > ++ * XXX Hack > > ++ * > > ++ * We re-use this error case to show case a cache load gadget: > > ++ * There is a mispredicted branch, which leads to prefetching > > ++ * the cache with attacker controlled data. > > ++ */ > > ++ asm volatile ( > > Obviously that can never be added to a standard kernel. No, that's why it is a patch, right? People want to test things, it's nice to have a way to easily do this. > And I don't see much point in shipping test cases that require non > standard kernel patching. The idea of shipping test cases is that > you can easily test them, but in this form it can't. It's better than having nothing at all, which is what we have today. So I see no harm in it, only benefits. thanks, greg k-h