From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.zytor.com (terminus.zytor.com [198.137.202.136]) (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 AC76135F603 for ; Tue, 24 Mar 2026 08:07:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.136 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774339662; cv=none; b=C1Uua42qOstbzB3/c8x7xMxc55CvvyJyFG9tqUJYbM2H9ZQH8vd64whlcWUn1vobn0+U97wHAfYuMNwEx/dfKpxIOhEHXLFApr4WIJ/dosoQS2X6z/5nQp1N3fTr0FT2Y6zqtfOTLO20OdyTC174BDaODj098X311i59UKLMTvg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774339662; c=relaxed/simple; bh=wXstj+X6FVeBfcf4f6tp2+lojnUM2Wr6vWyfSpb2qoo=; h=Date:From:To:CC:Subject:In-Reply-To:References:Message-ID: MIME-Version:Content-Type; b=AWaJdRCA95/POiMOcNpNvh08Tt17Cz8yoBiWfOOmPbpIsE3u5zB8W9TMXt562lCrkPPYg3nj2zIL5Np/xcxuZirPaDVtjnj54YrFy4wnPrZsdis65Maz0I2DlFeZoFKZZPwqY9TffOVUdqoQch8Ymkap8I6+BcnICKQnxtx0358= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zytor.com; spf=pass smtp.mailfrom=zytor.com; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b=eQEsZMtz; arc=none smtp.client-ip=198.137.202.136 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zytor.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=zytor.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b="eQEsZMtz" Received: from ehlo.thunderbird.net (c-76-133-66-138.hsd1.ca.comcast.net [76.133.66.138]) (authenticated bits=0) by mail.zytor.com (8.18.1/8.17.1) with ESMTPSA id 62O7p2rh029611 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NO); Tue, 24 Mar 2026 00:51:02 -0700 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.zytor.com 62O7p2rh029611 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2026022301; t=1774338663; bh=wXstj+X6FVeBfcf4f6tp2+lojnUM2Wr6vWyfSpb2qoo=; h=Date:From:To:CC:Subject:In-Reply-To:References:From; b=eQEsZMtzeHd7UEK0FJeeileb563u3vWDM1lfiT+Y41oPefpOG7Kl4PG1CZudRGxsX oCXgXXcrcjbdaM0cxSpFbmvqnWLrzagLK3PMbR0FP03y2fnbgnyzau1l2m6NGanPRa O5w7tRbkF18G8To8sO78Mk8/gv/8BlmWoUUCD7Dy5l7SlkdHyUX8c6ms1JcHqt2C3I 8L3Jx3PAkevrpVxY+k2eQjQ9OPcmtGSwuWZRK2WhSEChXXdcOwFJcI0cxdadHnzHgY ZcPk0A5G1Zz0rz5vpMv1SXg33LLi42XuMrjjd8t2U4guTMRprxo8aeFbVuOyy02AnB CPnZs4cwDMzFg== Date: Tue, 24 Mar 2026 00:50:55 -0700 From: "H. Peter Anvin" To: Sohil Mehta , Xin Li CC: Thomas Gleixner , Ingo Molnar , Borislav Petkov , 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 User-Agent: K-9 Mail for Android In-Reply-To: <1fb5ae44-d443-414f-9d63-3efce4b73bc9@intel.com> 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> Message-ID: 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-Transfer-Encoding: quoted-printable On March 23, 2026 10:08:42 PM PDT, Sohil Mehta = wrote: >On 3/23/2026 8:52 PM, H=2E Peter Anvin wrote: >>>> Nit: Would it be better to compare with "off" rather than not on? >>> >>> +1 :) >>> >>=20 >> It would change the meaning of something like "fred=3D0" though=2E >>=20 > >I don't believe we have ever supported fred=3D0 or fred=3D1, did we? > >Also, I am not sure about letting userspace be creative with command >line parameters :) For example, fred=3Dyes and fred=3Denable will both pa= ss >the same check and cause FRED to be disabled=2E Unfortunately right now we *are* being creative: anytime but the exact str= ing "on" disables FRED=2E This is a general problem=2E In the kernel; overa= ll I feel promoting foo=3D syntax for booleans, which was not the original = style, was a mistake, but here we are=2E Anyway, I don't have a strong preference and I think we can leave that pol= icy decision to the maintainers=2E=20