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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 50853C3DA7D for ; Thu, 5 Jan 2023 15:02:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233871AbjAEPC2 (ORCPT ); Thu, 5 Jan 2023 10:02:28 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42970 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233893AbjAEOih (ORCPT ); Thu, 5 Jan 2023 09:38:37 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2A14659331; Thu, 5 Jan 2023 06:38:36 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id DE046B81AF8; Thu, 5 Jan 2023 14:38:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EF626C433EF; Thu, 5 Jan 2023 14:38:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1672929513; bh=G5YNmA8ky3bK+urw6zEhSYdIXfh6FrcGi/1KX+rdWGY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=kWHP6ROg0Nu4Xd0xp5ri7h/b9Bo/9GbbKJJZMbaVpxT6mhqpUGovDYnqHKgClMOh3 OuOzM7RDmqzmPgev4zlXYBXr0fuRCb5/7n1bkmBN58NFTU4QixQFCXupvOQMTfA7YT ZPHYSCAKK8B+Bjzux3Z7pyB2yiFeJXhj/KCvfvXc= Date: Thu, 5 Jan 2023 15:38:30 +0100 From: Greg KH To: "Raphael S. Carvalho" Cc: Aaron Lu , Dave Hansen , Pavel Boldin , Pavel Boldin , Moritz Lipp , Daniel Gruss , Michael Schwarz , linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] selftest/x86/meltdown: Add a selftest for meltdown Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 05, 2023 at 11:11:15AM -0300, Raphael S. Carvalho wrote: > On Thu, Jan 5, 2023 at 10:42 AM Greg KH wrote: > > > > On Thu, Jan 05, 2023 at 08:35:05PM +0800, Aaron Lu wrote: > > > To capture potential programming errors like mistakenly setting Global > > > bit on kernel page table entries, a selftest for meltdown is added. > > > > > > This selftest is based on Pavel Boldin's work at: > > > https://github.com/linux-test-project/ltp/blob/master/testcases/cve/meltdown.c > > > > > > In addition to the existing test of reading kernel variable > > > saved_command_line from user space, one more test of reading user local > > > variable through kernel direct map address is added. For the existing > > > test(reading saved_command_line) to report a failure, both the high kernel > > > mapping and low kernel mapping have to be in leaked state; For the added > > > test(read local var), only low kernel mapping leak is enough to trigger > > > a test fail, so both tests are useful. > > > > > > Test results of 10 runs: > > > > > > On v6.1-rc8 with nopti kernel cmdline option: > > > > > > host test_out_rate_1 test_out_rate_2 > > > lkp-bdw-de1 50% 100% > > > lkp-hsw-d01 70% 100% > > > lkp-hsw-d02 0% 80% > > > lkp-hsw-d03 60% 100% > > > lkp-hsw-d04 20% 100% > > > lkp-hsw-d05 60% 100% > > > lkp-ivb-d01 0% 70% > > > lkp-kbl-d01 100% 100% > > > lkp-skl-d02 100% 90% > > > lkp-skl-d03 90% 100% > > > lkp-skl-d05 60% 100% > > > kbl-vm 100% 80% > > > 2 other machines have 0% rate for both tests. > > > > > > bdw=broadwell, hsw=haswell, ivb=ivybridge, etc. > > > > > > test_out_rate_1: test reports fail rate for the test of reading > > > saved_command_line from user space; > > > test_out_rate_2: test reports fail rate for the test of reading user > > > local variable through kernel direct map address in user space. > > > > > > On v5.19 without nopti cmdline option: > > > host test_out_rate_2 > > > lkp-bdw-de1 80% > > > lkp-hsw-4ex1 50% > > > lkp-hsw-d01 30% > > > lkp-hsw-d03 10% > > > lkp-hsw-d04 10% > > > lkp-kbl-d01 10% > > > kbl-vm 80% > > > 7 other machines have 0% rate for test2. > > > > > > Also tested on an i386 VM with 512M memory and the test out rate is 100% > > > when adding nopti to kernel cmdline with v6.1-rc8. > > > > > > Main changes I made from Pavel Boldin's meltdown test are: > > > - Replace rdtscll() and clflush() with kernel's implementation; > > > - Reimplement find_symbol_in_file() to avoid bringing in LTP's library > > > functions; > > > - Coding style changes: placing the function return type in the same > > > line of the function. > > > > > > Signed-off-by: Aaron Lu > > > --- > > > Notable changes from RFC v3: > > > - Drop RFC tag; > > > - Change the base code from zlib licensed one to GPL licensed one. > > > > Sorry, but this still gets my NAK for the issues raised in previous > > reviews that are not addressed here for some reason :( > > Greg, the selftest is no longer based on > https://github.com/IAIK/meltdown/blob/master/LICENSE, which is > originally zlib licensed. In this version, Aaron is basing the test on > https://github.com/linux-test-project/ltp/blob/master/testcases/cve/meltdown.c, > which is indeed licensed with: GPL-2.0-or-later That's not what the submission looks like, it looks a lot like the last one from the first defines and variables... But hey, what do I know, I'm not a lawyer which is why I keep insisting that one from Intel actually read over this submission and sign-off on it to verify that they agree with all of this. thanks, greg k-h