From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1162711AbdAIDku (ORCPT ); Sun, 8 Jan 2017 22:40:50 -0500 Received: from szxga01-in.huawei.com ([58.251.152.64]:9293 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1162689AbdAIDkp (ORCPT ); Sun, 8 Jan 2017 22:40:45 -0500 Subject: Re: [PATCH] ACPI/PCI: Fix bus range comparation in pci_mcfg_lookup To: "Rafael J. Wysocki" , Len Brown , Tomasz Nowicki , Jayachandran C , Lorenzo Pieralisi , jorn Helgaas References: <1483513206-113046-1-git-send-email-wangzhou1@hisilicon.com> CC: , , , , , From: Zhou Wang Message-ID: <58730600.3080802@hisilicon.com> Date: Mon, 9 Jan 2017 11:39:44 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 MIME-Version: 1.0 In-Reply-To: <1483513206-113046-1-git-send-email-wangzhou1@hisilicon.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.63.139.185] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A090202.58730621.0040,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-06-18 04:22:30, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 95e8542e51467ef7c7d3e6caf2f4f24d Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2017/1/4 15:00, Zhou Wang wrote: > The configuration data provided by an MCFG region (ie PCI segment and > bus range) may span multiple host bridges. > > Current code in pci_mcfg_lookup() carries out an exact match of host > bridge bus range start value against the MCFG region(s) bus range start > value which would cause configurations like the following: > > MCFG region: > bus range: 0x00~0xff. > segment: 0. > > PCI host bridges configuration (segment numbers and bus ranges): > host bridge 1: > bus range: 0x00~0x1f. > segment: 0. > host bridge 2: > bus range: 0x20~0x4f. > segment: 0. > > to fail, in that the bus range start value for host bridge 2 does > not match the bus range start value of the respective MCFG region. > > Relax the bus range check in pci_mcfg_lookup() to cater for > PCI configurations with multiple host bridges sharing the same > MCFG region. > > Signed-off-by: Zhou Wang > Reviewed-by: Tomasz Nowicki > Acked-by: Lorenzo Pieralisi > --- > drivers/acpi/pci_mcfg.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/drivers/acpi/pci_mcfg.c b/drivers/acpi/pci_mcfg.c > index a6a4cea..2944353 100644 > --- a/drivers/acpi/pci_mcfg.c > +++ b/drivers/acpi/pci_mcfg.c > @@ -195,11 +195,10 @@ int pci_mcfg_lookup(struct acpi_pci_root *root, struct resource *cfgres, > goto skip_lookup; > > /* > - * We expect exact match, unless MCFG entry end bus covers more than > - * specified by caller. > + * We expect the range in bus_res in the coverage of MCFG bus range. > */ > list_for_each_entry(e, &pci_mcfg_list, list) { > - if (e->segment == seg && e->bus_start == bus_res->start && > + if (e->segment == seg && e->bus_start <= bus_res->start && > e->bus_end >= bus_res->end) { > root->mcfg_addr = e->addr; > } > Hi Rafael, Could you please look into this patch if you have time? Thanks, Zhou