From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-292030-1518535698-2-11438218460156719831 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, FREEMAIL_FORGED_FROMDOMAIN 0.195, FREEMAIL_FROM 0.001, HEADER_FROM_DIFFERENT_DOMAINS 0.001, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='com', MailFrom='org' X-Spam-charsets: plain='UTF-8' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1518535698; b=KxOpD31EQ2wK0ofWmHFOawAar9bewAIWIhFeYLWd5csC2ZT JRjVUsItn2djKbqmo7DgXc7kQ+FYRqf0WFxl2iZgnX/ksiOAQ6hKqrHLfdLeF8H8 xjIh4GYCMDwvxPdoKtZceVE9DErA5KwEc1JXy0QaqZA4wtgANZkVs/Jp8j8m/WAk 3bdVrVsApfbqx0eWZZpe+RQTWgtKrwkynjtCduGQ7uY5N0HSrlnoTS0PRMGBTusM rbLs2wfd4N1XL47Sogc8JydsccI0WaHFUS+dAwA+bhe8O15bo7H4/CLT/TB79+bJ 5AJGnHAx2E3IIHS4h5YeDSVw5NKSrCislmJNPyA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=mime-version:in-reply-to:references:from :date:message-id:subject:to:cc:content-type:sender:list-id; s= arctest; t=1518535698; bh=SqP3mpuiLMyNNiHN/VtHbmnGfX4V2a5EhDYr/z SJyRw=; b=gdDb+jhmATudmyhdmdhiSHrhx2ZerxwoNq88NFDY/3WYdCjtLRjx1C fPVTJRmxs78r9KoqDVzs341cpVKyjXWzsoVBEEU6Lk3NnrmGVyhYXZsJRVUgjKqe p6aXgHD2V1o8zij/LjOtM00OjWoBBWBYb+iLX6BJyMvzuNU82mKnumUq0QT4EdK1 c1IkH1rmDZR8liJermJ2NTbMoeRmIvRj4kMmBlekxH+m9B+vhdgygzxSRHZIkr3S 5mcbu20zVgJjftglM6R6WPvPZGxrwA2N7D9UL/1RJVj4d+YS/pWFBAtm3bzinbwj cB5ouDSZ9bkB22CBxbEY2GhauvaFjdyA== ARC-Authentication-Results: i=1; mx4.messagingengine.com; arc=none (no signatures found); dkim=pass (2048-bit rsa key sha256) header.d=gmail.com header.i=@gmail.com header.b=L0w4+RCn x-bits=2048 x-keytype=rsa x-algorithm=sha256 x-selector=20161025; dmarc=pass (p=none,has-list-id=yes,d=none) header.from=gmail.com; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-google-dkim=pass (2048-bit rsa key) header.d=1e100.net header.i=@1e100.net header.b=eKMQKf4L; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=gmail.com header.result=pass header_is_org_domain=yes Authentication-Results: mx4.messagingengine.com; arc=none (no signatures found); dkim=pass (2048-bit rsa key sha256) header.d=gmail.com header.i=@gmail.com header.b=L0w4+RCn x-bits=2048 x-keytype=rsa x-algorithm=sha256 x-selector=20161025; dmarc=pass (p=none,has-list-id=yes,d=none) header.from=gmail.com; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-google-dkim=pass (2048-bit rsa key) header.d=1e100.net header.i=@1e100.net header.b=eKMQKf4L; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=gmail.com header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964939AbeBMP1u (ORCPT ); Tue, 13 Feb 2018 10:27:50 -0500 Received: from mail-lf0-f54.google.com ([209.85.215.54]:42732 "EHLO mail-lf0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752177AbeBMP1t (ORCPT ); Tue, 13 Feb 2018 10:27:49 -0500 X-Google-Smtp-Source: AH8x226RzsdQbnpgoYvclbC6af05hmjbcd5tXgm6vDGbe+FNd4YFivNpLYh4zMQR0zMgCLVBJDr9N4oWBuqmmAZ7MfU= MIME-Version: 1.0 In-Reply-To: References: <20180209133931.211869118@linuxfoundation.org> <20180209133934.259299920@linuxfoundation.org> <20180213150007.GJ26982@kroah.com> From: Nick Lowe Date: Tue, 13 Feb 2018 15:27:47 +0000 Message-ID: Subject: Re: [PATCH 4.9 43/92] x86/pti: Do not enable PTI on CPUs which are not vulnerable to Meltdown To: Arjan van de Ven Cc: Greg Kroah-Hartman , linux-kernel@vger.kernel.org, stable@vger.kernel.org, David Woodhouse , Thomas Gleixner , Borislav Petkov , Dave Hansen , gnomes@lxorguk.ukuu.org.uk, ak@linux.intel.com, ashok.raj@intel.com, karahmed@amazon.de, torvalds@linux-foundation.org, peterz@infradead.org, Borislav Petkov , pbonzini@redhat.com, tim.c.chen@linux.intel.com Content-Type: text/plain; charset="UTF-8" Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: Hi Arjan and Greg, Sorry if I am not being clear enough. My point is that there is a check for X86_VENDOR_AMD now in two places. It is still hardcoded for the auto boot option which I think should not be there. The patch on that basis looked incomplete to me. Put another way, there is no effect to the auto option where the contents of cpu_no_meltdown[] are changed and cpu_vulnerable_to_meltdown returns differently. The auto option does not make use of a determination of the X86_BUG_CPU_MELTDOWN state. This seems wrong to me. It does not seem correct to me for the auto option to have this duplication with a check for just X86_VENDOR_AMD. Regards, Nick