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 AF3D9C5479D for ; Wed, 11 Jan 2023 14:33:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232778AbjAKOdO (ORCPT ); Wed, 11 Jan 2023 09:33:14 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43062 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238543AbjAKOcF (ORCPT ); Wed, 11 Jan 2023 09:32:05 -0500 Received: from mail.skyhub.de (mail.skyhub.de [5.9.137.197]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DAB3B19C1B for ; Wed, 11 Jan 2023 06:30:20 -0800 (PST) Received: from zn.tnic (p5de8e9fe.dip0.t-ipconnect.de [93.232.233.254]) (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 421351EC06C1; Wed, 11 Jan 2023 15:30:19 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1673447419; 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=NA7mwk/Ho8iSsKJyfJlHX4iE/hrNeawT1dy1bhzSM7A=; b=F9KN9T/+5lKvqdSQTZ1Ns7N0wweGvK/IWkC6oOj5tgDc5h3b23py0t5QUDeIQFTLrINAzN PpwKHMv6ItAFMzQlRqmuZMHNl3V8EXQHMJTPZKHa9T+8hy8lKEuyZdBVMboly8MrhATBGO pkj+wvSCD6zkMegEy77RDhHgU7Qxuv8= Date: Wed, 11 Jan 2023 15:30:18 +0100 From: Borislav Petkov To: Xin Li Cc: linux-kernel@vger.kernel.org, x86@kernel.org, tglx@linutronix.de, mingo@redhat.com, dave.hansen@linux.intel.com, hpa@zytor.com, peterz@infradead.org, brgerst@gmail.com, chang.seok.bae@intel.com, jgross@suse.com Subject: Re: [PATCH v5 5/5] x86/gsseg: use the LKGS instruction if available for load_gs_index() Message-ID: References: <20221128164028.4570-1-xin3.li@intel.com> <20221128164028.4570-6-xin3.li@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20221128164028.4570-6-xin3.li@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 28, 2022 at 08:40:28AM -0800, Xin Li wrote: > From: "H. Peter Anvin (Intel)" > > The LKGS instruction atomically loads a segment descriptor into the > %gs descriptor registers, *except* that %gs.base is unchanged, and the > base is instead loaded into MSR_IA32_KERNEL_GS_BASE, which is exactly > what we want this function to do. > > Signed-off-by: H. Peter Anvin (Intel) > Signed-off-by: Peter Zijlstra (Intel) > Signed-off-by: Brian Gerst > Signed-off-by: Juergen Gross > Signed-off-by: Xin Li I'm reading this SOB chain as hpa wrote it -> then it went to Peter -> then to Brian -> then to Juergen -> and you're sending it. I'm pretty sure that cannot be right. > --- > > Changes since v4: > * Clear the LKGS feature from Xen PV guests (Juergen Gross). > > Changes since v3: > * We want less ASM not more, thus keep local_irq_save/restore() inside > native_load_gs_index() (Thomas Gleixner). > * For paravirt enabled kernels, initialize pv_ops.cpu.load_gs_index to > native_lkgs (Thomas Gleixner). > > Changes since v2: > * Mark DI as input and output (+D) as in V1, since the exception handler > modifies it (Brian Gerst). > > Changes since v1: > * Use EX_TYPE_ZERO_REG instead of fixup code in the obsolete .fixup code > section (Peter Zijlstra). > * Add a comment that states the LKGS_DI macro will be repalced with "lkgs %di" > once the binutils support the LKGS instruction (Peter Zijlstra). I guess that explains what the SOB chain is supposed to mean - you've gotten review feedback. But that doesn't need such a SOB chain. Sounds like you need to refresh on Documentation/process/submitting-patches.rst Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette