From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751681AbcG0Cv2 (ORCPT ); Tue, 26 Jul 2016 22:51:28 -0400 Received: from mga03.intel.com ([134.134.136.65]:57536 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750764AbcG0CvT (ORCPT ); Tue, 26 Jul 2016 22:51:19 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.28,428,1464678000"; d="scan'208";a="740249135" From: Rui Wang To: helgaas@kernel.org Cc: tglx@linutronix.de, rjw@rjwysocki.net, tony.luck@intel.com, bhelgaas@google.com, linux-acpi@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, rui.y.wang@intel.com Subject: Re: [PATCH 3/4] x86/ioapic: Fix lost ioapic resource after hot-removal and hotadd Date: Wed, 27 Jul 2016 10:35:12 +0800 Message-Id: <1469586912-21693-1-git-send-email-rui.y.wang@intel.com> X-Mailer: git-send-email 1.7.5.4 In-Reply-To: <20160726202422.GF15037@localhost> References: <20160726202422.GF15037@localhost> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, July 27, 2016 4:24 AM, Bjorn Helgaas wrote: > On Wed, Jul 27, 2016 at 12:13:16AM +0800, Rui Wang wrote: > > ioapic resource at 0xfecxxxxx gets lost from /proc/iomem after > > hot-removing and then hot-adding the ioapic devices. > > > > After system boot, in /proc/iomem: > > fec00000-fecfffff : PNP0003:00 > > fec00000-fec003ff : IOAPIC 0 > > fec01000-fec013ff : IOAPIC 1 > > fec40000-fec403ff : IOAPIC 2 > > fec80000-fec803ff : IOAPIC 3 > > fecc0000-fecc03ff : IOAPIC 4 > > > > Then hot-remove IOAPIC 2 and hot-add it again: > > fec00000-fecfffff : PNP0003:00 > > fec00000-fec003ff : IOAPIC 0 > > fec01000-fec013ff : IOAPIC 1 > > fec80000-fec803ff : IOAPIC 3 > > fecc0000-fecc03ff : IOAPIC 4 > > > > The range at 0xfec40000 is lost from /proc/iomem. It is because > > handle_ioapic_add() requests resource from either PCI config BAR or > > acpi _CRS, not both. But Intel platforms map the IOxAPIC registers > > s/acpi/ACPI/ > s/ioapic/IOAPIC/ throughout > > > at both the PCI config BAR (called MBAR) and the 0xfecX_YZ00 to > > 0xfecX_Y2FF range (called ABAR). Both of the ranges should be claimed > > I guess you mean the 0xfecX_YZ00-0xfecX_Y2FF range appears in _CRS? Yes. That range appears in _CRS for each IOAPIC. I'll make it cleaner in the commit message. Thanks Rui