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 <xyj...@linux.vnet.ibm.com>
---
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
