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 E589BC4CEC9 for ; Tue, 17 Sep 2019 06:46:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A036120640 for ; Tue, 17 Sep 2019 06:46:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="UMYw0f+j" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404328AbfIQGqU (ORCPT ); Tue, 17 Sep 2019 02:46:20 -0400 Received: from mail.skyhub.de ([5.9.137.197]:60016 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726953AbfIQGqT (ORCPT ); Tue, 17 Sep 2019 02:46:19 -0400 Received: from nazgul.tnic (unknown [193.86.95.52]) (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 CB7771EC0200; Tue, 17 Sep 2019 08:46:17 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1568702778; 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=9Q0Z13rG711uvWRmfQeCjyd2F/ANVybw/Hkd7OjcJ+k=; b=UMYw0f+j81fcQuCG7ECcpHsVLbVG9alHrC0/6b8TqoWSohdnLoJyU/hHYtNk8lTLsbMLU/ EF9zGd03VHAckmOpVQvt4YVaVkT39pU1toKGQuSjHJnX5qUHUspRS4y2kiMsESxoxNbCKP dRxae3zO6LYvSxKaji6M0M4BGLV+rbo= Date: Tue, 17 Sep 2019 08:46:12 +0200 From: Borislav Petkov To: Thomas Gleixner Cc: "Raj, Ashok" , Johannes Erdfelt , Boris Ostrovsky , Mihai Carabas , "H. Peter Anvin" , Ingo Molnar , Jon Grimm , kanth.ghatraju@oracle.com, konrad.wilk@oracle.com, patrick.colp@oracle.com, 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: <20190917064612.GA12174@nazgul.tnic> References: <20190905222706.GA4422@otc-nc-03> <20190906144039.GA29569@sventech.com> <20190907003338.GA14807@araj-mobl1.jf.intel.com> <20190917003122.GA3005@otc-nc-03> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: 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 Tue, Sep 17, 2019 at 08:37:10AM +0200, Thomas Gleixner wrote: > So what happens if the ucode update "fixes" one of the executed > instructions on the fly? Is that guaranteed to be safe? There is nothing > which says so. You'd expect that when you load microcode on the core, the one thread does the loading and the other SMT thread is in a holding pattern. That would be optimal. Considering the dancing through hoops we're doing to keep all threads quiesced, I'd be sceptical that is the case... -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. --