From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936821AbdAIVqF (ORCPT ); Mon, 9 Jan 2017 16:46:05 -0500 Received: from mail-oi0-f68.google.com ([209.85.218.68]:32886 "EHLO mail-oi0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752155AbdAIVqA (ORCPT ); Mon, 9 Jan 2017 16:46:00 -0500 MIME-Version: 1.0 In-Reply-To: <58730600.3080802@hisilicon.com> References: <1483513206-113046-1-git-send-email-wangzhou1@hisilicon.com> <58730600.3080802@hisilicon.com> From: "Rafael J. Wysocki" Date: Mon, 9 Jan 2017 22:45:59 +0100 X-Google-Sender-Auth: YgYbJEUM2cuvfLdk9LQgvy4_Kf8 Message-ID: Subject: Re: [PATCH] ACPI/PCI: Fix bus range comparation in pci_mcfg_lookup To: Zhou Wang Cc: "Rafael J. Wysocki" , Len Brown , Tomasz Nowicki , Jayachandran C , Lorenzo Pieralisi , jorn Helgaas , Dongdong Liu , Gabriele Paoloni , xuwei5@hisilicon.com, ACPI Devel Maling List , Linux PCI , Linux Kernel Mailing 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 On Mon, Jan 9, 2017 at 4:39 AM, Zhou Wang wrote: > 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? Well, it makes sense to me, but this is PCI, so Bjorn has to decide here. Thanks, Rafael