Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753920AbcDRK6O (ORCPT ); Mon, 18 Apr 2016 06:58:14 -0400 Received: from e28smtp05.in.ibm.com ([125.16.236.5]:55646 "EHLO e28smtp05.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753694AbcDRK5I (ORCPT ); Mon, 18 Apr 2016 06:57:08 -0400 X-IBM-Helo: d28relay08.in.ibm.com X-IBM-MailFrom: xyjxie@linux.vnet.ibm.com X-IBM-RcptTo: linux-doc@vger.kernel.org;linux-pci@vger.kernel.org;linux-kernel@vger.kernel.org;kvm@vger.kernel.org From: Yongji Xie To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, iommu@lists.linux-foundation.org, linux-doc@vger.kernel.org Cc: alex.williamson@redhat.com, bhelgaas@google.com, aik@ozlabs.ru, benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, corbet@lwn.net, warrier@linux.vnet.ibm.com, zhong@linux.vnet.ibm.com, nikunj@linux.vnet.ibm.com, gwshan@linux.vnet.ibm.com, Yongji Xie Subject: [RFC v6 03/10] PCI: Add a new option for resource_alignment to reassign alignment Date: Mon, 18 Apr 2016 18:55:59 +0800 Message-Id: <1460976961-29328-3-git-send-email-xyjxie@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1460976961-29328-1-git-send-email-xyjxie@linux.vnet.ibm.com> References: <1460976961-29328-1-git-send-email-xyjxie@linux.vnet.ibm.com> X-TM-AS-MML: disable x-cbid: 16041810-0017-0000-0000-00001E13CB97 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3984 Lines: 115 When using resource_alignment kernel parameter, the current implement reassigns the alignment by changing resources' size which can potentially break some drivers. For example, the driver uses the size to locate some register whose length is related to the size. This patch adds a new option "noresize" for the parameter to solve this problem. Signed-off-by: Yongji Xie --- Documentation/kernel-parameters.txt | 5 ++++- drivers/pci/pci.c | 35 +++++++++++++++++++++++++---------- 2 files changed, 29 insertions(+), 11 deletions(-) diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 9a53c92..d8b29ab 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -2912,13 +2912,16 @@ bytes respectively. Such letter suffixes can also be entirely omitted. window. The default value is 64 megabytes. resource_alignment= Format: - [@][:]:.[; ...] + [@][:]:. + [:noresize][; ...] Specifies alignment and device to reassign aligned memory resources. If is not specified, PAGE_SIZE is used as alignment. PCI-PCI bridge can be specified, if resource windows need to be expanded. + noresize: Don't change the resources' sizes when + reassigning alignment. ecrc= Enable/disable PCIe ECRC (transaction layer end-to-end CRC checking). bios: Use BIOS/firmware settings. This is the diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 77b7494..7564ccc 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -4594,11 +4594,13 @@ static DEFINE_SPINLOCK(resource_alignment_lock); /** * pci_specified_resource_alignment - get resource alignment specified by user. * @dev: the PCI device to get + * @resize: whether or not to change resources' size when reassigning alignment * * RETURNS: Resource alignment if it is specified. * Zero if it is not specified. */ -static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev) +static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev, + bool *resize) { int seg, bus, slot, func, align_order, count; resource_size_t align = 0; @@ -4632,6 +4634,11 @@ static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev) } } p += count; + if (!strncmp(p, ":noresize", 9)) { + *resize = false; + p += 9; + } else + *resize = true; if (seg == pci_domain_nr(dev->bus) && bus == dev->bus->number && slot == PCI_SLOT(dev->devfn) && @@ -4664,11 +4671,12 @@ void pci_reassigndev_resource_alignment(struct pci_dev *dev) { int i; struct resource *r; + bool resize = true; resource_size_t align, size; u16 command; /* check if specified PCI is target device to reassign */ - align = pci_specified_resource_alignment(dev); + align = pci_specified_resource_alignment(dev, &resize); if (!align) return; @@ -4690,15 +4698,22 @@ void pci_reassigndev_resource_alignment(struct pci_dev *dev) if (!(r->flags & IORESOURCE_MEM)) continue; size = resource_size(r); - if (size < align) { - size = align; - dev_info(&dev->dev, - "Rounding up size of resource #%d to %#llx.\n", - i, (unsigned long long)size); + if (resize) { + if (size < align) { + size = align; + dev_info(&dev->dev, + "Rounding up size of resource #%d to %#llx.\n", + i, (unsigned long long)size); + } + r->flags |= IORESOURCE_UNSET; + r->end = size - 1; + r->start = 0; + } else { + r->flags &= ~IORESOURCE_SIZEALIGN; + r->flags |= IORESOURCE_STARTALIGN | IORESOURCE_UNSET; + r->start = max(align, size); + r->end = r->start + size - 1; } - r->flags |= IORESOURCE_UNSET; - r->end = size - 1; - r->start = 0; } /* Need to disable bridge's resource window, * to enable the kernel to reassign new resource -- 1.7.9.5