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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 5D9A3C3A59F for ; Thu, 29 Aug 2019 06:09:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1BDE222CED for ; Thu, 29 Aug 2019 06:09:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="cu92urpL" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727495AbfH2GJx (ORCPT ); Thu, 29 Aug 2019 02:09:53 -0400 Received: from mail.skyhub.de ([5.9.137.197]:52886 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726330AbfH2GJw (ORCPT ); Thu, 29 Aug 2019 02:09:52 -0400 Received: from zn.tnic (p200300EC2F0D0C00C4AC36401DE27C46.dip0.t-ipconnect.de [IPv6:2003:ec:2f0d:c00:c4ac:3640:1de2:7c46]) (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 716081EC0B6E; Thu, 29 Aug 2019 08:09:51 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1567058991; 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=Jj3hmfHkutQGkUAabd2SGodGbh+Q3mOjtDk+Bx2jxgA=; b=cu92urpLpwKFnxncJm4XSu8FXQ3eXvrVWuKHqcJ9FEtVBz6+JvFqHcTe7zRYHLMseQI19z 9f6eamT7a19dM7nu57xqwEAZ55sWzIExYAxveWd+aJ66vQ9AJ1QaWjHKbleW34F4OLEcof QfglIoEvi8mr9UjFagS23991FM1UpsU= Date: Thu, 29 Aug 2019 08:09:42 +0200 From: Borislav Petkov To: Ashok Raj Cc: Mihai Carabas , Boris Ostrovsky , "H. Peter Anvin" , Ingo Molnar , Jon Grimm , kanth.ghatraju@oracle.com, konrad.wilk@oracle.com, patrick.colp@oracle.com, Thomas Gleixner , Tom Lendacky , x86-ml , linux-kernel@vger.kernel.org Subject: Re: [PATCH] x86/microcode: Add an option to reload microcode even if revision is unchanged Message-ID: <20190829060942.GA1312@zn.tnic> References: <1567056803-6640-1-git-send-email-ashok.raj@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1567056803-6640-1-git-send-email-ashok.raj@intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 28, 2019 at 10:33:22PM -0700, Ashok Raj wrote: > During microcode development, its often required to test different versions > of microcode. Intel microcode loader enforces loading only if the revision is > greater than what is currently loaded on the cpu. Overriding this behavior > allows us to reuse the same revision during development cycles. > This facilty also allows us to share debug microcode with development > partners for getting feedback before microcode release. > > Microcode developers should have other ways to check which > of their internal version is actually loaded. For e.g. checking a > temporary MSR for instance. In order to reload the same microcode do as > shown below. > > # echo 2 > /sys/devices/system/cpu/microcode/reload > > as root. > > > I tested this on top of the parallel ucode load patch > > https://lore.kernel.org/r/1566506627-16536-2-git-send-email-mihai.carabas@oracle.com/ > > v2: [Mihai] Address comments from Boris > - Support for AMD > - add taint flag > - removed global force_ucode_load and parameterized it. As I've said before, I don't like the churn in this version and how it turns out. I'll have a look at how to do this cleanly when I get some free cycles. -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.