From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bjorn Helgaas Subject: Re: [PATCH] ACPI/PCI: Fix bus range comparation in pci_mcfg_lookup Date: Wed, 11 Jan 2017 15:37:27 -0600 Message-ID: <20170111213727.GO14532@bhelgaas-glaptop.roam.corp.google.com> References: <1483513206-113046-1-git-send-email-wangzhou1@hisilicon.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail.kernel.org ([198.145.29.136]:34212 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755170AbdAKVhc (ORCPT ); Wed, 11 Jan 2017 16:37:32 -0500 Content-Disposition: inline In-Reply-To: <1483513206-113046-1-git-send-email-wangzhou1@hisilicon.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Zhou Wang Cc: "Rafael J. Wysocki" , Len Brown , Tomasz Nowicki , Jayachandran C , Lorenzo Pieralisi , jorn Helgaas , liudongdong3@huawei.com, gabriele.paoloni@huawei.com, xuwei5@hisilicon.com, linux-acpi@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org On Wed, Jan 04, 2017 at 03:00:06PM +0800, 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 Applied to pci/enumeration for v4.11 with the following changelog: PCI/ACPI: Fix bus range comparison in pci_mcfg_lookup() The configuration data provided by an MCFG entry, i.e., PCI segment and bus range, may span multiple host bridges. pci_mcfg_lookup() previously required an exact match of the host bridge starting bus and the MCFG starting bus, which made the following configuration fail: MCFG region: segment: 0 bus range: 0x00-0xff host bridge segment: 0 bus range: 0x20-0x4f Relax the bus range check in pci_mcfg_lookup() so we can use any MCFG entry that contains the required bus range, as we do in pci_mmconfig_lookup(). [bhelgaas: changelog] Signed-off-by: Zhou Wang Signed-off-by: Bjorn Helgaas 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; > } > -- > 1.9.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html