From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:58773 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750922AbdBOGpU (ORCPT ); Wed, 15 Feb 2017 01:45:20 -0500 Received: from pps.filterd (m0098416.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v1F6hS7r170899 for ; Wed, 15 Feb 2017 01:45:20 -0500 Received: from e35.co.us.ibm.com (e35.co.us.ibm.com [32.97.110.153]) by mx0b-001b2d01.pphosted.com with ESMTP id 28mf8pcwxk-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 15 Feb 2017 01:45:19 -0500 Received: from localhost by e35.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 14 Feb 2017 23:45:19 -0700 From: Yongji Xie To: bhelgaas@google.com Cc: linux-pci@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, alex.williamson@redhat.com, gwshan@linux.vnet.ibm.com, aik@ozlabs.ru, benh@kernel.crashing.org, mpe@ellerman.id.au, paulus@samba.org, zhong@linux.vnet.ibm.com Subject: [PATCH v9 3/3] PCI: Don't extend device's size when using default alignment for all devices Date: Wed, 15 Feb 2017 14:45:06 +0800 In-Reply-To: <1487141106-2503-1-git-send-email-xyjxie@linux.vnet.ibm.com> References: <1487141106-2503-1-git-send-email-xyjxie@linux.vnet.ibm.com> Message-Id: <1487141106-2503-4-git-send-email-xyjxie@linux.vnet.ibm.com> Sender: linux-pci-owner@vger.kernel.org List-ID: Currently we reassign the alignment by extending resources' size in pci_reassigndev_resource_alignment(). This could potentially break some drivers when the driver uses the size to locate register whose length is related to the size. Some examples as below: - misc\Hpilo.c: off = pci_resource_len(pdev, bar) - 0x2000; - net\ethernet\chelsio\cxgb4\cxgb4_uld.h: (pci_resource_len((pdev), 2) - roundup_pow_of_two((vres)->ocq.size)) - infiniband\hw\nes\Nes_hw.c: num_pds = pci_resource_len(nesdev->pcidev, BAR_1) >> PAGE_SHIFT; This risk could be easily prevented before because we only had one way (kernel parameter resource_alignment) to touch those codes. And even some users may be happy to see the extended size. But now we define a default alignment for all devices which would also touch those codes. It would be hard to prevent the risk in this case. So this patch tries to use START_ALIGNMENT to identify the resource's alignment without extending the size when the alignment reassigning is caused by the default alignment. Signed-off-by: Yongji Xie --- drivers/pci/pci.c | 34 ++++++++++++++++++++++++---------- 1 files changed, 24 insertions(+), 10 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 2622e9b..0017e5e 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -4958,7 +4958,8 @@ void pci_ignore_hotplug(struct pci_dev *dev) * 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; unsigned short vendor, device, subsystem_vendor, subsystem_device; @@ -5002,6 +5003,7 @@ static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev) (!device || (device == dev->device)) && (!subsystem_vendor || (subsystem_vendor == dev->subsystem_vendor)) && (!subsystem_device || (subsystem_device == dev->subsystem_device))) { + *resize = true; if (align_order == -1) align = PAGE_SIZE; else @@ -5027,6 +5029,7 @@ static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev) bus == dev->bus->number && slot == PCI_SLOT(dev->devfn) && func == PCI_FUNC(dev->devfn)) { + *resize = true; if (align_order == -1) align = PAGE_SIZE; else @@ -5059,6 +5062,7 @@ void pci_reassigndev_resource_alignment(struct pci_dev *dev) struct resource *r; resource_size_t align, size; u16 command; + bool resize = false; /* * VF BARs are read-only zero according to SR-IOV spec r1.1, sec @@ -5070,7 +5074,7 @@ void pci_reassigndev_resource_alignment(struct pci_dev *dev) return; /* 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; @@ -5098,15 +5102,25 @@ void pci_reassigndev_resource_alignment(struct pci_dev *dev) } 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 { + if (size < align) { + r->flags &= ~IORESOURCE_SIZEALIGN; + r->flags |= IORESOURCE_STARTALIGN | + IORESOURCE_UNSET; + r->start = align; + 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 -- 1.7.1