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 16A6FC433FE for ; Thu, 28 Apr 2022 17:25:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349667AbiD1R2u (ORCPT ); Thu, 28 Apr 2022 13:28:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55840 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244596AbiD1R2r (ORCPT ); Thu, 28 Apr 2022 13:28:47 -0400 Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CA38A2A272; Thu, 28 Apr 2022 10:25:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1651166731; x=1682702731; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=DYG9Rn3kLiVzbYKPE5ieeehd4+ubv2m1EeKlPf4Sh2Q=; b=koiSeosoEK/WAY2R+xeazVi621ruDH3yTi/kw41XEvsQwVJmlJpOAyzP s8WM6gJ0VZJJiOmzXirA8BZuGx6oLdbeqRKan0PEjdPIGc39+krk8zhs6 goyDE1452vL/sFtOj07urmL6t22uAaAPsA7RrIwQZvlxAAvueIev8+p3G BCrAnBOrWiffHrTlW5vmmXMRX9uOz1E0onkmJUqn1n8lpSxJyQs5P5fuU O+wMTbJx7ln5m/UpsPBvSpHKqej+rwwy2gfwZu7fKJylKjjT57nafDw1f vURkeRI4OzR8hLrDZv/aru5chxhrxQAt6eN1hBOgdQZ+0bLvR04uBx3W1 g==; X-IronPort-AV: E=McAfee;i="6400,9594,10331"; a="246917809" X-IronPort-AV: E=Sophos;i="5.91,295,1647327600"; d="scan'208";a="246917809" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Apr 2022 10:25:28 -0700 X-IronPort-AV: E=Sophos;i="5.91,295,1647327600"; d="scan'208";a="559784532" Received: from mpoursae-mobl2.amr.corp.intel.com (HELO [10.212.0.84]) ([10.212.0.84]) by orsmga007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Apr 2022 10:25:27 -0700 Message-ID: <7e63912a-895f-d3b3-3173-336beaa86d08@intel.com> Date: Thu, 28 Apr 2022 10:25:43 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Subject: Re: [PATCH v3 20/21] x86/virt/tdx: Add kernel command line to opt-in TDX host support Content-Language: en-US To: Kai Huang , linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: seanjc@google.com, pbonzini@redhat.com, len.brown@intel.com, tony.luck@intel.com, rafael.j.wysocki@intel.com, reinette.chatre@intel.com, dan.j.williams@intel.com, peterz@infradead.org, ak@linux.intel.com, kirill.shutemov@linux.intel.com, sathyanarayanan.kuppuswamy@linux.intel.com, isaku.yamahata@intel.com References: <0d50d13e5f9bd590ee97ff150f1393c4d99a8fa0.1649219184.git.kai.huang@intel.com> From: Dave Hansen In-Reply-To: <0d50d13e5f9bd590ee97ff150f1393c4d99a8fa0.1649219184.git.kai.huang@intel.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/5/22 21:49, Kai Huang wrote: > Enabling TDX consumes additional memory (used by TDX as metadata) and > additional initialization time. Introduce a kernel command line to > allow to opt-in TDX host kernel support when user truly wants to use > TDX. >From the cover letter: "This series doesn't initialize TDX at boot time" Could you please square that circle for me? How does a feature that doesn't get initialized a boot time need a boot-time command line opt-in?