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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 A1A4AC6778D for ; Tue, 11 Sep 2018 06:11:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 48C72206BB for ; Tue, 11 Sep 2018 06:11:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 48C72206BB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lynx.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727651AbeIKLIo (ORCPT ); Tue, 11 Sep 2018 07:08:44 -0400 Received: from [216.100.252.242] ([216.100.252.242]:38853 "EHLO asmtp.lnxw.com" rhost-flags-FAIL-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726569AbeIKLIn (ORCPT ); Tue, 11 Sep 2018 07:08:43 -0400 X-Greylist: delayed 472 seconds by postgrey-1.27 at vger.kernel.org; Tue, 11 Sep 2018 07:08:43 EDT Received: from [10.21.42.214] ([10.21.42.214]) (authenticated bits=0) by asmtp.lnxw.com (8.13.8/8.13.8) with ESMTP id w8B62jqj009943 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NO); Mon, 10 Sep 2018 23:02:47 -0700 Subject: Re: x86/apic: MSI address malformed for "flat" driver To: Thomas Gleixner , Philipp Eppelt Cc: linux-kernel@vger.kernel.org References: From: Cyril Novikov Message-ID: <27bccfd2-0ede-cd3a-2717-741d3dffebdf@lynx.com> Date: Mon, 10 Sep 2018 23:02:46 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/7/2018 12:11 PM, Thomas Gleixner wrote: > On Thu, 6 Sep 2018, Philipp Eppelt wrote: >> >> The "flat" driver defines the MSI addressing scheme to be used as >> logical addressing in flat mode. The MSI msg address is composed >> accordingly, but sets MSI_ADDR_REDIRECTION_CPU which is a zero at bit[3]. > > Correct. That's what it means: > > * When RH is 0, the interrupt is directed to the processor listed in the > Destination ID field. > > So for DM: > > * If RH is 0, then the DM bit is ignored and the message is sent ahead > independent of whether the physical or logical destination mode is > used. > > which is means that the delivery does not do any magic redirections, > because the Redirection Hint is off. If RH is set, then the delivery can > redirect according to the rules in the DM section. We are not using that > because we want targeted single CPU delivery. > > The interpretation of the DID field is purely depending on the local APIC > itself by matching the APIC ID against the DID field. And the local APIC ID > of CPU0 is 1 << 0, i.e. 0x1 which matches the MSI message you see. I believe you are wrong here and the local APIC ID of CPU0 is 0. processor : 0 vendor_id : GenuineIntel ... physical id : 0 siblings : 8 core id : 0 cpu cores : 4 apicid : 0 The fact that the code works means that DM is not ignored when RH is 0. In other words, RH=0 DM=1 means logical destination mode. -- Cyril