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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 53E15C433B4 for ; Mon, 10 May 2021 17:22:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1D5B061352 for ; Mon, 10 May 2021 17:22:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232296AbhEJRXq (ORCPT ); Mon, 10 May 2021 13:23:46 -0400 Received: from mga02.intel.com ([134.134.136.20]:29432 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231381AbhEJRXo (ORCPT ); Mon, 10 May 2021 13:23:44 -0400 IronPort-SDR: cTZIc3Dy8vCfZOSHClJhgvQEwgslemH6yffgZXYF+jtqB4+lIz5287ItzpN9zonT9XpK3oKOfL 2REb5A88CPXQ== X-IronPort-AV: E=McAfee;i="6200,9189,9980"; a="186380052" X-IronPort-AV: E=Sophos;i="5.82,287,1613462400"; d="scan'208";a="186380052" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 May 2021 10:22:38 -0700 IronPort-SDR: yeBh7/THipK27vGT9BNdOezKYbGpTBar79hWpMunY4quKozgF+1gaCutIBcxq2EY/oBWAm8oku W9DaNfmASv+g== X-IronPort-AV: E=Sophos;i="5.82,287,1613462400"; d="scan'208";a="536492536" Received: from tassilo.jf.intel.com ([10.54.74.11]) by fmsmga001-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 May 2021 10:22:38 -0700 Date: Mon, 10 May 2021 10:22:37 -0700 From: Andi Kleen To: "Kuppuswamy, Sathyanarayanan" Cc: "Rafael J. Wysocki" , Rafael J Wysocki , Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" , Peter Zijlstra , Len Brown , Robert Moore , Erik Kaneda , ACPI Devel Maling List , "open list:ACPI COMPONENT ARCHITECTURE (ACPICA)" , Linux Kernel Mailing List , the arch/x86 maintainers , Sean Christopherson Subject: Re: [PATCH v3 3/3] x86/acpi, x86/boot: Add multiprocessor wake-up support Message-ID: <20210510172237.GU4032392@tassilo.jf.intel.com> References: <20210426023941.729334-1-sathyanarayanan.kuppuswamy@linux.intel.com> <20210426023941.729334-4-sathyanarayanan.kuppuswamy@linux.intel.com> <97e14cdc-ea98-18b8-0c89-db52440a7716@linux.intel.com> <4fa40e7a-bcb2-db0f-8dc5-28728b14377d@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4fa40e7a-bcb2-db0f-8dc5-28728b14377d@linux.intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On Mon, May 10, 2021 at 10:10:24AM -0700, Kuppuswamy, Sathyanarayanan wrote: > > > On 5/10/21 9:55 AM, Rafael J. Wysocki wrote: > > I'm not sure how my comment regarding the fact that for a given CPU > > this function is only usable once has been addressed. > > > > While it may not be a practical concern in the use case that you are > > after (TDX), this is a generic mechanism and it needs to cover other > > possible usage scenarios. > > For the same CPU, if we try to use mailbox again, firmware will not > respond to it. So the command will timeout and return error. Right because the firmware code doesn't run anymore. The only possibility would be for Linux to put back some code that spins and waits again, but that would be quite pointless and wasteful. -Andi