Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755322AbcJGSzu (ORCPT ); Fri, 7 Oct 2016 14:55:50 -0400 Received: from mail-vk0-f67.google.com ([209.85.213.67]:35217 "EHLO mail-vk0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750975AbcJGSzl (ORCPT ); Fri, 7 Oct 2016 14:55:41 -0400 MIME-Version: 1.0 In-Reply-To: References: <1472114120-3281-4-git-send-email-douly.fnst@cn.fujitsu.com> <4608f474-c49e-550b-90e2-c5f4c25e00f5@cn.fujitsu.com> From: Yinghai Lu Date: Fri, 7 Oct 2016 11:55:39 -0700 X-Google-Sender-Auth: gcyi_5u_Nq18HclwCv6i69tx9zU Message-ID: Subject: Re: [tip:x86/apic] x86/acpi: Introduce persistent storage for cpuid <-> apicid mapping To: Thomas Gleixner Cc: Dou Liyang , Linux Kernel Mailing List , Ingo Molnar , "H. Peter Anvin" , "linux-tip-commits@vger.kernel.org" , Tony Luck , "Rafael J. Wysocki" , "lenb@kernel.org" , "Zheng, Lv" , Bob Moore , ACPI Devel Maling List Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 829 Lines: 23 On Fri, Oct 7, 2016 at 6:00 AM, Thomas Gleixner wrote: > On Fri, 7 Oct 2016, Thomas Gleixner wrote: >> On Fri, 7 Oct 2016, Dou Liyang wrote: >> > Is it possible that the "-1/oxffffffff" could appear in the MADT which is one >> > of the ACPI tables? >> >> According to the SDM the x2apic id is a 32bit ID, so 0xffffffff is a >> legitimate value. > > The ACPI spec says that bit 0 of the x2apic flags field tells whether the > logical processor is present or not. So the proper check for x2apic is that > flag. > > The lapic structure has the same flag, but the kernel ignores the flags for > both lapic and x2apic. > > I'm going to apply the minimal fix of checking for id == 0xff in > acpi_lapic_parse() for now, but this needs to be revisited and fixed > proper. Good to me. Thanks for fixing it. Yinghai