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 4B9D2C433EF for ; Mon, 2 May 2022 05:04:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1383306AbiEBFHh (ORCPT ); Mon, 2 May 2022 01:07:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44336 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346303AbiEBFHe (ORCPT ); Mon, 2 May 2022 01:07:34 -0400 Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 99B5E18B2F; Sun, 1 May 2022 22:04:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1651467847; x=1683003847; h=message-id:subject:from:to:cc:date:in-reply-to: references:mime-version:content-transfer-encoding; bh=V1kJORjn9br3AwkVpZzF5nhWVGElfcC89uM3ZN5Q7cY=; b=gVJwl2PMfLj6VpOQNkWMvxOuwhnAbKplGGK7G3Jx+6gZ4rezkXjKajpA c8RWIIhQeXMK2jjKjrvEnTdT7yRsIvV0cWSjmSNvtc/LPAnI/EfUubqxm cAyhG6BHvQBQB93ydUfndyLy4+X+09MAiv2wfvVS1vIq0dNbeZDgm2Aik aNc8vmIyLluBVXhokmeBTynPPmZCzZybP7v81IY8Nati2m6bn56Iy/Aky 64jmCvA/Jfwhud+rjagttrRqwGwN1H5iRuBw8oxYBVfmPUMlQ81dUIAq2 Hm5O2c0unCMlzpAyd7sFP4NRpdsYvxCAuWlwC8+Uv7FO8mFjn5l67cowd w==; X-IronPort-AV: E=McAfee;i="6400,9594,10334"; a="247674779" X-IronPort-AV: E=Sophos;i="5.91,190,1647327600"; d="scan'208";a="247674779" Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 May 2022 22:04:07 -0700 X-IronPort-AV: E=Sophos;i="5.91,190,1647327600"; d="scan'208";a="886061235" Received: from bwu50-mobl.amr.corp.intel.com (HELO khuang2-desk.gar.corp.intel.com) ([10.254.2.219]) by fmsmga005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 May 2022 22:04:04 -0700 Message-ID: <33e3c91973dd22cada87d9c78e3e4b9eb4da9778.camel@intel.com> Subject: Re: [PATCH v3 09/21] x86/virt/tdx: Get information about TDX module and convertible memory From: Kai Huang To: Dave Hansen , 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 Date: Mon, 02 May 2022 17:04:02 +1200 In-Reply-To: <4aea41ea-211f-fbde-34e9-4c4467ebc848@intel.com> References: <145620795852bf24ba2124a3f8234fd4aaac19d4.1649219184.git.kai.huang@intel.com> <0bab7221179229317a11311386c968bd0d40e344.camel@intel.com> <98f81eed-e532-75bc-d2d8-4e020517b634@intel.com> <4aea41ea-211f-fbde-34e9-4c4467ebc848@intel.com> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.42.4 (3.42.4-1.fc35) MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2022-04-29 at 10:47 -0700, Dave Hansen wrote: > On 4/28/22 16:14, Kai Huang wrote: > > On Thu, 2022-04-28 at 07:06 -0700, Dave Hansen wrote: > > > On 4/27/22 17:15, Kai Huang wrote: > > > > > Couldn't we get rid of that comment if you did something like: > > > > > > > > > > ret = tdx_get_sysinfo(&tdx_cmr_array, &tdx_sysinfo); > > > > > > > > Yes will do. > > > > > > > > > and preferably make the variables function-local. > > > > > > > > 'tdx_sysinfo' will be used by KVM too. > > > > > > In other words, it's not a part of this series so I can't review whether > > > this statement is correct or whether there's a better way to hand this > > > information over to KVM. > > > > > > This (minor) nugget influencing the design also isn't even commented or > > > addressed in the changelog. > > > > TDSYSINFO_STRUCT is 1024B and CMR array is 512B, so I don't think it should be > > in the stack. I can change to use dynamic allocation at the beginning and free > > it at the end of the function. KVM support patches can change it to static > > variable in the file. > > 2k of stack is big, but it isn't a deal breaker for something that's not > nested anywhere and that's only called once in a pretty controlled > setting and not in interrupt context. I wouldn't cry about it. OK. I'll change to use function local variables for both of them. -- Thanks, -Kai