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 2E007C433EF for ; Thu, 21 Apr 2022 02:42:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1383794AbiDUCpB (ORCPT ); Wed, 20 Apr 2022 22:45:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45006 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229462AbiDUCo7 (ORCPT ); Wed, 20 Apr 2022 22:44:59 -0400 Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C35F3B3E; Wed, 20 Apr 2022 19:42:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1650508930; x=1682044930; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=QvTMlm8zkmv6XEevm736zdXwgrbOlcTEqT+gBwIB7y4=; b=caKcb+/QUTyH4FNxoZQxr+8dwFpzmMnRMR/C0971aMoF+8dyRUlM2UYD kH2ZbPVQQI5v9ezlgqD7nlugtMf2favJunhWHJXrmjBGh+GeSATZ61ZNg 5shjaKRjQ60q3hA+K8niJB/kBXD29IBNGMM8Md2wpHyvID8dFozEey5eD Zsp3roEB80MGp8zgyIWdwXf5hOjuZ8HdLsvuZ1hGysJRJ59paaDVQvLYv XYQjSV1RNSkcjwpxr6Z+SqHvX8ePLzxTfXLWgiczwjskIcuNkzNAuVzPB t00DH0IYd7BtK0I8l3kE09IEZ3VgGtbh0h6hhMEwro0YGpPaJKe05l5ht Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10323"; a="244798148" X-IronPort-AV: E=Sophos;i="5.90,277,1643702400"; d="scan'208";a="244798148" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Apr 2022 19:42:10 -0700 X-IronPort-AV: E=Sophos;i="5.90,277,1643702400"; d="scan'208";a="555520403" Received: from dmertma-mobl4.amr.corp.intel.com (HELO [10.209.83.57]) ([10.209.83.57]) by orsmga007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Apr 2022 19:42:09 -0700 Message-ID: <1e184b44-8024-b8ae-98a8-cf2b6f78df61@linux.intel.com> Date: Wed, 20 Apr 2022 19:42:06 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Firefox/91.0 Thunderbird/91.7.0 Subject: Re: [PATCH v3 4/4] platform/x86: intel_tdx_attest: Add TDX Guest attestation interface driver Content-Language: en-US To: Kai Huang , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, Hans de Goede , Mark Gross Cc: "H . Peter Anvin" , "Kirill A . Shutemov" , Tony Luck , Andi Kleen , linux-kernel@vger.kernel.org, platform-driver-x86@vger.kernel.org, isaku.yamahata@gmail.com References: <20220415220109.282834-1-sathyanarayanan.kuppuswamy@linux.intel.com> <20220415220109.282834-5-sathyanarayanan.kuppuswamy@linux.intel.com> <420a4d689f73f9f7dc1ef71c61da75b7c9777a3f.camel@intel.com> From: Sathyanarayanan Kuppuswamy In-Reply-To: <420a4d689f73f9f7dc1ef71c61da75b7c9777a3f.camel@intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/20/22 5:11 PM, Kai Huang wrote: > On Wed, 2022-04-20 at 16:45 -0700, Sathyanarayanan Kuppuswamy wrote: >> If we want to support multiple GetQuote requests in parallel, then we >> need some way to uniquely identify the GetQuote requests. So that when >> we get completion notification, we can understand which request is >> completed. This part is not mentioned/discussed in ABI spec. So we want >> to serialize the requests for now. >> > > Yes it's unfortunate that this part (whether concurrent GetQuote requests are > supported by TDX architecture) is not explicitly mentioned in GHCI spec. I am > fine with only supporting GetQuote requests one by one. AFAICT there's no > request to support concurrent GetQuote requests anyway. What concerns me is > exactly how explain this. > > As I said, we have GET_QUOTE_IN_FLIGHT flag now. Theoretically, you can queue > multiple GetQuote requests, and when you receive the interrupt, you check which > buffer has GET_QUOTE_IN_FLIGHT cleared. That buffer is the one with Quote > ready. However I am not 100% sure whether above will always work. Interrupt > can get lost when there are multiple Quotes ready in multiple buffer in very > short time period, etc? Perhaps Isaku can provide more input here. Either supported or not, it should be mentioned in the GHCI spec. Currently, there are no details related to it. If it is supported, the specification should include the protocol to use. I will check with Isaku about it. > > Anyway, how about explaining in this way: > > "The GHCI spec doesn't clearly say whether TDX can support or how to support > multiple GetQuote requests in parallel. Attestation request is not supposed to > be frequent and should not be in performance critical path. Only support > GetQuote requests in serialized way for now." It seems good enough. I will use it. > > -- Sathyanarayanan Kuppuswamy Linux Kernel Developer