From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.alien8.de (mail.alien8.de [65.109.113.108]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C6DE73FB04B for ; Wed, 25 Mar 2026 16:30:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=65.109.113.108 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774456256; cv=none; b=X0dom69jLay/7busVeM3ctchX9YNs4EN6OKYoZZSP5fRzbhrlmXVvnqnqOaDZGycZlqq4rZkVYxGRRMn390LMv/35hztIOS7L85ypwB8ogSQkOdVS7foWuUQcppxkcj8ZYFTDzD+qkjFL0VV4uhN6aZTFOhYt2PJyvZapP6tYbc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774456256; c=relaxed/simple; bh=ac2Z0OvTyvHOJnA6wLTpjeev2eFFQFQGPp/GTn5MGuA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=uKjPVAOcDZe8Vf/3q7RqciPXg/Un7qQyVvwu2O5FG6yC9OCZYF9G4pxtn3UUJN8/DeO6lvp8BAAQfd4j7H5PXdH8PpR8RJ7C/H409DRhK8ccNHNgZ3w1BLPjoMwQErASUxqXz+6Rlw7OTMxxodOySOIyfnDyw/4SF1uj4xGRW98= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=alien8.de; spf=pass smtp.mailfrom=alien8.de; dkim=pass (4096-bit key) header.d=alien8.de header.i=@alien8.de header.b=H3Q7tAYE; arc=none smtp.client-ip=65.109.113.108 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=alien8.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=alien8.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (4096-bit key) header.d=alien8.de header.i=@alien8.de header.b="H3Q7tAYE" Received: from localhost (localhost.localdomain [127.0.0.1]) by mail.alien8.de (SuperMail on ZX Spectrum 128k) with ESMTP id 1368740E01B5; Wed, 25 Mar 2026 16:30:51 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at mail.alien8.de Authentication-Results: mail.alien8.de (amavisd-new); dkim=pass (4096-bit key) header.d=alien8.de Received: from mail.alien8.de ([127.0.0.1]) by localhost (mail.alien8.de [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id vw6Eep7AI7-o; Wed, 25 Mar 2026 16:30:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=alien8; t=1774456245; bh=z2cg/Lf1q33IDyATd+vzuWi5AVKv6/Cyz/cymANMaY0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=H3Q7tAYEjWEC5kTDvzMP6g2Ri4T7IXB0pc0zf1vFcZ9wiNoNgN/gJpjsBv9FEBXeJ IMNCANR3i2daVlZNdg/oPHOb4ho9RDlx/AsR9dvnrkUSWikqKnAciSwZqqtOxcl2mZ iT2sWByh2OGWYOUYInI/Vzh2wLkhk+osNJs42L+rlxG0V4vmxxELx09MELzzYw+JN1 wIVq6RvyM1twk0JRL3b7FJ5nbo7roj0XPNkaed01Q0zpyztTy37oiYiHvh1t6HLm63 siHYZCxQodukfdWAYEFavmWY9BOtXLc4y5/MaocMsYQxo0RbCHkhK/gQ8lSTl1OCs4 SA234F31rV4srYWrjFtStWOWEsavsO+6ld/9b4q/zpx48C/NoLzMyyHZy8ECkTzeWj vHvP69whKjfxD3qLLBfvn7GeIDgsMAMpzt9pZ8HpMznQUuTb10eAk9Vqzlnq/VQVao GSYctyj3Jtf/G0FlA4jaSFPTxIZURlu+lya0bCEZcsROt97a5VUj2eg0TuRPCnDsz8 D6GfXdZSWf0e+hL5QyqEiHY2jHc6yFNmAKOu2xutRRCqGY2a7DTKmiTYuZUFdVE5jz gNJEg73b8dvlYp7Fb67lt2khz7Eou+nTDFxr58RRUMfdsyC5noMY+fSDjsHedubLNr g2t3jKEFeGJaNwJTAnsv5a6w= Received: from zn.tnic (p5de8e020.dip0.t-ipconnect.de [93.232.224.32]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature ECDSA (P-256) server-digest SHA256) (No client certificate requested) by mail.alien8.de (SuperMail on ZX Spectrum 128k) with UTF8SMTPSA id 9BB0840E0031; Wed, 25 Mar 2026 16:30:34 +0000 (UTC) Date: Wed, 25 Mar 2026 17:30:28 +0100 From: Borislav Petkov To: "H. Peter Anvin" Cc: Sohil Mehta , Xin Li , Thomas Gleixner , Ingo Molnar , Dave Hansen , x86@kernel.org, "Peter Zijlstra (Intel)" , Kees Cook , "Ahmed S. Darwish" , linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/2] x86/fred: enable FRED by default Message-ID: <20260325163028.GAacQNpB7DlkyS4MJ4@fat_crate.local> References: <20260323201510.1537333-1-hpa@zytor.com> <84489fd4-aa23-4ba1-b5a1-c1baafb6718d@intel.com> <927AE575-3C10-427E-9C4B-0238CBF8301E@zytor.com> <763cbc92-fda0-454e-a2dd-919671db15c3@zytor.com> <1fb5ae44-d443-414f-9d63-3efce4b73bc9@intel.com> <8cba266d-4d3d-4058-a4b4-b937395e50e3@intel.com> <20260324195351.GOacLrz90cagXTepUx@fat_crate.local> <8bb320bb-62e0-4252-8ef9-9b6aa04b02ba@zytor.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <8bb320bb-62e0-4252-8ef9-9b6aa04b02ba@zytor.com> On Wed, Mar 25, 2026 at 09:22:35AM -0700, H. Peter Anvin wrote: > Well, that's easy. I just didn't want to change existing behavior. If that is > your policy decision then I'm fine with that. > > We don't even need a new function; it is actually an even smaller change to > the code than this patchset version, so I'll rev the patchset. > > It WOULD be good to have a global function to parse boolean arguments in a > kernel-coherent manner, but that is out of scope for this patchset. Right. > > Because you should not poke at clearing CPUID features unless you know what > > you're doing and this cmdline option should not exist at all. But we have it > > so... > > > > Well, it is useful for testing code paths for legacy hardware. ... which would presume you know what you're doing. clearcpuid= is not something you or I or anyone else wants to debug when people start clearing random CPUID bits without knowing any better. Thus the tainting. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette