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Groups > linux.kernel > #1434454

[PATCH v3 4/7] PCI: Add a new option for resource_alignment to reassign alignment

From Yongji Xie <xyjxie@linux.vnet.ibm.com>
Newsgroups linux.kernel
Subject [PATCH v3 4/7] PCI: Add a new option for resource_alignment to reassign alignment
Date 2016-06-30 13:00 +0200
Message-ID <rPHRo-72-17@gated-at.bofh.it> (permalink)
References <rPHRn-72-1@gated-at.bofh.it>
Organization linux.* mail to news gateway

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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 <xyjxie@linux.vnet.ibm.com>
---
 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 82b42c9..c4802f5 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2997,13 +2997,16 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 				window. The default value is 64 megabytes.
 		resource_alignment=
 				Format:
-				[<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...]
+				[<order of align>@][<domain>:]<bus>:<slot>.<func>
+				[:noresize][; ...]
 				Specifies alignment and device to reassign
 				aligned memory resources.
 				If <order of align> 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 6241cfc..1d80a94 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4748,11 +4748,13 @@ 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;
@@ -4787,6 +4789,11 @@ 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) &&
@@ -4819,6 +4826,7 @@ void pci_reassigndev_resource_alignment(struct pci_dev *dev)
 {
 	int i;
 	struct resource *r;
+	bool resize = true;
 	resource_size_t align, size;
 
 	/* We should never try to reassign VF's alignment */
@@ -4826,7 +4834,7 @@ 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;
 
@@ -4848,15 +4856,22 @@ void pci_reassigndev_resource_alignment(struct pci_dev *dev)
 			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

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Thread

[PATCH v3 0/7] PCI: Add support for enforcing all MMIO BARs not to share PAGE_SIZE Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-06-30 13:00 +0200
  [PATCH v3 3/7] PCI: Do not disable memory decoding in pci_reassigndev_resource_alignment() Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-06-30 13:00 +0200
    Re: [PATCH v3 3/7] PCI: Do not disable memory decoding in  pci_reassigndev_resource_alignment() Gavin Shan <gwshan@linux.vnet.ibm.com> - 2016-07-01 03:00 +0200
      Re: [PATCH v3 3/7] PCI: Do not disable memory decoding in  pci_reassigndev_resource_alignment() Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-07-01 10:10 +0200
  [PATCH v3 1/7] PCI: Ignore enforced alignment when kernel uses existing firmware setup Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-06-30 13:00 +0200
    Re: [PATCH v3 1/7] PCI: Ignore enforced alignment when kernel uses  existing firmware setup Gavin Shan <gwshan@linux.vnet.ibm.com> - 2016-07-01 02:30 +0200
      Re: [PATCH v3 1/7] PCI: Ignore enforced alignment when kernel uses  existing firmware setup Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-07-01 06:50 +0200
  [PATCH v3 2/7] PCI: Ignore enforced alignment to VF BARs Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-06-30 13:00 +0200
    Re: [PATCH v3 2/7] PCI: Ignore enforced alignment to VF BARs Gavin Shan <gwshan@linux.vnet.ibm.com> - 2016-07-01 02:50 +0200
      Re: [PATCH v3 2/7] PCI: Ignore enforced alignment to VF BARs Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-07-01 07:30 +0200
        Re: [PATCH v3 2/7] PCI: Ignore enforced alignment to VF BARs Gavin Shan <gwshan@linux.vnet.ibm.com> - 2016-07-01 08:10 +0200
          Re: [PATCH v3 2/7] PCI: Ignore enforced alignment to VF BARs Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-07-01 08:50 +0200
            Re: [PATCH v3 2/7] PCI: Ignore enforced alignment to VF BARs Gavin Shan <gwshan@linux.vnet.ibm.com> - 2016-07-02 02:40 +0200
  [PATCH v3 7/7] PCI: Add a macro to set default alignment for all PCI devices Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-06-30 13:00 +0200
  [PATCH v3 4/7] PCI: Add a new option for resource_alignment to reassign alignment Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-06-30 13:00 +0200
    Re: [PATCH v3 4/7] PCI: Add a new option for resource_alignment to  reassign alignment Gavin Shan <gwshan@linux.vnet.ibm.com> - 2016-07-01 05:40 +0200
      Re: [PATCH v3 4/7] PCI: Add a new option for resource_alignment to  reassign alignment Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-07-01 09:00 +0200
  [PATCH v3 6/7] PCI: Add support for enforcing all MMIO BARs to be page aligned Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-06-30 13:00 +0200
  [PATCH v3 5/7] PCI: Do not use IORESOURCE_STARTALIGN to identify bridge resources Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-06-30 13:00 +0200
    Re: [PATCH v3 5/7] PCI: Do not use IORESOURCE_STARTALIGN to identify  bridge resources Gavin Shan <gwshan@linux.vnet.ibm.com> - 2016-07-01 04:40 +0200
      Re: [PATCH v3 5/7] PCI: Do not use IORESOURCE_STARTALIGN to identify  bridge resources Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-07-01 09:10 +0200
        Re: [PATCH v3 5/7] PCI: Do not use IORESOURCE_STARTALIGN to identify  bridge resources Gavin Shan <gwshan@linux.vnet.ibm.com> - 2016-07-02 02:40 +0200

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