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 BB532C433EF for ; Fri, 8 Apr 2022 03:55:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234003AbiDHD5S (ORCPT ); Thu, 7 Apr 2022 23:57:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54816 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234018AbiDHD5D (ORCPT ); Thu, 7 Apr 2022 23:57:03 -0400 Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E11BDD555C for ; Thu, 7 Apr 2022 20:54:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1649390098; x=1680926098; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=cgaS9ZvpFeSv+RbYtEAFTm8IymBUs7K6+jgyHaDx9hI=; b=ILQhtt8bF3nCaGH5vZZNZn8foMTqra8dnZQy3SI4X39ddEflQzFENPfK Mxp3d2JOyr+O9LlEgbO020LPBalMp1+rhPmsA7RsKFojpKP/vKTqatRth sr2Dar9o6bOdWmpEEzebMZJC/RfSt5s0hpxO1mErJwKqT3zAvXc3YxWZ9 wKTiTkMqwTJWsQpl3IRkZC7ePG29YQg1t8MKdrHdWHjUifZkHn17lRbcU Ppd0iu6jk8P1xMP190sHLxQp0eN2LlVckL3J/5Rfxs77ehpNmShWZxBEi ka0Y220cuZBKgCdv0IdOCCmxSUT2XPmhkquDPl9K+WndHFCsACFl61K9c w==; X-IronPort-AV: E=McAfee;i="6400,9594,10310"; a="241435240" X-IronPort-AV: E=Sophos;i="5.90,243,1643702400"; d="scan'208";a="241435240" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Apr 2022 20:54:58 -0700 X-IronPort-AV: E=Sophos;i="5.90,243,1643702400"; d="scan'208";a="571337373" Received: from vjcarmax-mobl.amr.corp.intel.com (HELO [10.252.140.177]) ([10.252.140.177]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Apr 2022 20:54:57 -0700 Message-ID: <8d6789ba-85d3-3482-4bbb-3693073bea06@linux.intel.com> Date: Thu, 7 Apr 2022 20:54:56 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Firefox/91.0 Thunderbird/91.5.0 Subject: Re: [PATCH v2] x86/apic: Do apic driver probe for "nosmp" use case Content-Language: en-US To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H . Peter Anvin" Cc: linux-kernel@vger.kernel.org, "Kirill A . Shutemov" , "Rafael J . Wysocki" , Tony Luck References: <20220406185430.552016-1-sathyanarayanan.kuppuswamy@linux.intel.com> <87mtgxzuzz.ffs@tglx> From: Sathyanarayanan Kuppuswamy In-Reply-To: <87mtgxzuzz.ffs@tglx> 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 4/6/22 3:50 PM, Thomas Gleixner wrote: > On Wed, Apr 06 2022 at 18:54, Kuppuswamy Sathyanarayanan wrote: >> diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c >> index b70344bf6600..79b8b521981c 100644 >> --- a/arch/x86/kernel/apic/apic.c >> +++ b/arch/x86/kernel/apic/apic.c >> @@ -1419,22 +1419,22 @@ void __init apic_intr_mode_init(void) >> return; >> case APIC_VIRTUAL_WIRE: >> pr_info("APIC: Switch to virtual wire mode setup\n"); >> - default_setup_apic_routing(); >> break; >> case APIC_VIRTUAL_WIRE_NO_CONFIG: >> pr_info("APIC: Switch to virtual wire mode setup with no configuration\n"); >> upmode = true; >> - default_setup_apic_routing(); >> break; >> case APIC_SYMMETRIC_IO: >> pr_info("APIC: Switch to symmetric I/O mode setup\n"); >> - default_setup_apic_routing(); >> break; >> case APIC_SYMMETRIC_IO_NO_ROUTING: >> pr_info("APIC: Switch to symmetric I/O mode setup in no SMP routine\n"); >> + upmode = true; > > Why? The changelog tells nothing about this change. > > And it's not correct because the APIC configuration is there, otherwise > __apic_intr_mode_select() would have returned APIC_VIRTUAL_WIRE_NO_CONFIG. Makes sense. I initially thought since APIC_SYMMETRIC_IO_NO_ROUTING is only used in non-smp case (setup_max_cpus == 0), we can force uniprocessor mode. But checking again, my assumption is incorrect. It will only be used in non MADT/MP case. I will remove the upmode change in next version. > > Thanks, > > tglx -- Sathyanarayanan Kuppuswamy Linux Kernel Developer