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 ADE82C7EE2F for ; Sun, 26 Feb 2023 11:18:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229639AbjBZLSO (ORCPT ); Sun, 26 Feb 2023 06:18:14 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47096 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229470AbjBZLSM (ORCPT ); Sun, 26 Feb 2023 06:18:12 -0500 Received: from mail.skyhub.de (mail.skyhub.de [5.9.137.197]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5A1E34EE1; Sun, 26 Feb 2023 03:18:11 -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 C4A311EC05B0; Sun, 26 Feb 2023 12:18:09 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1677410289; 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=Fqca05TAjyju01u0iIdb8z1cG5MT45Cv6Y7lhY3Umj8=; b=jIwESVcTEQVvy+6uCr73JGWEzdJ4pig7GZmp2tyYMtE8Mp5gPFQ39fx1t41A2BJW/S0C7D fMkYE3m7OxzkOasn/G17ICTgpmzA/diz6Aq17Rj5O7WNtiJSAvfpEy1SVZTUNXfEt9sGly fTwBBZQutvKO3/lJ9F2BAmR6TgvySKU= Date: Sun, 26 Feb 2023 12:18:06 +0100 From: Borislav Petkov To: Josh Poimboeuf Cc: Pawan Gupta , Kim Phillips , x86@kernel.org, Boris Ostrovsky , Dave Hansen , "H. Peter Anvin" , Ingo Molnar , Joao Martins , Jonathan Corbet , Konrad Rzeszutek Wilk , Paolo Bonzini , Sean Christopherson , Thomas Gleixner , David Woodhouse , Greg Kroah-Hartman , Juergen Gross , Peter Zijlstra , Tony Luck , Tom Lendacky , Alexey Kardashevskiy , kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] x86/CPU/AMD: Make sure EFER[AIBRSE] is set Message-ID: References: <20230225000931.wrednfun4jifkqau@treble> <20230225005221.425yahqvxb57c43x@desk> <20230225013202.g7tibykvylprsxs5@treble> <20230225172832.sqdd7dejkkmjxpt6@treble> <20230225234330.caznxpkjhq3u5tls@treble> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20230225234330.caznxpkjhq3u5tls@treble> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Feb 25, 2023 at 03:43:30PM -0800, Josh Poimboeuf wrote: > Hm? So code in bugs.c is not vendor-specific? That seems circular and > I don't get your point. Lemme try that again... So there's an obvious benefit of keeping vendor-specific CPU code in one place: Intel stuff in cpu/intel*, AMD stuff in cpu/amd.c The sekjority stuff is still vendor-specific CPU code. Now, if you wanna add a function pointer ->bugs_init or so, say, to struct cpu_dev and keep the respective code in amd.c or intel.c, then we get the best of both worlds: - vendor-specific code remains in the respective file - you have a vendor-specific function which does hw vuln-specific work *without* vendor checks and so on > Right, so rather than spreading all the bug-related MSR logic around, > just do it in one spot. It is all CPU init code and I'm wondering if splitting stuff by vendor wouldn't make all that maze in bugs.c a lot more palatable. And get rid of $ git grep VENDOR arch/x86/kernel/cpu/bugs.c | wc -l 11 those, for starters. There's this trade-off of 1. keeping bugs setup code in one place - but then you need to do vendor checks and the other CPU setup code is somewhere else and it is probably related, MSR_AMD64_DE_CFG_LFENCE_SERIALIZE_BIT in amd.c for example. or 2. separating it into their respective files. Then the respective vendor code is simple because you don't need vendor checks. It would need to be done in a slick way, though, so that it remains maintainable. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette