[RFC PATCH v4 1/7] PCI: Add a new option for resource_alignment to reassign alignment
From: Yongji Xie <hidden>
Date: 2016-03-07 07:49:45
Also in:
kvm, linux-pci, lkml
Subsystem:
documentation, pci subsystem, the rest · Maintainers:
Jonathan Corbet, Bjorn Helgaas, Linus Torvalds
When using resource_alignment kernel parameter, the current implement reassigns the alignment by changing resources' size which can potentially break some drivers. So this patch adds a new option "noresize" for the parameter to solve this problem. Signed-off-by: Yongji Xie <redacted> --- Documentation/kernel-parameters.txt | 5 ++++- drivers/pci/pci.c | 36 +++++++++++++++++++++++++---------- 2 files changed, 30 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: - [<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 602eb42..760cce5 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c@@ -4598,7 +4598,8 @@ static DEFINE_SPINLOCK(resource_alignment_lock); * 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;
@@ -4626,6 +4627,11 @@ 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) &&
@@ -4658,11 +4664,12 @@ void pci_reassigndev_resource_alignment(struct pci_dev *dev) { int i; struct resource *r; + bool resize; 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;
@@ -4684,15 +4691,24 @@ 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 { + if (size > align) + align = size; + 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
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1.7.9.5