diff options
| -rw-r--r-- | drivers/pci/pci.c | 59 |
1 files changed, 43 insertions, 16 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 7eb6eb3..c140cb2 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -4959,11 +4959,13 @@ 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; unsigned short vendor, device, subsystem_vendor, subsystem_device; @@ -5005,6 +5007,7 @@ 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 @@ -5030,6 +5033,7 @@ 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 @@ -5050,7 +5054,7 @@ out: } static void pci_request_resource_alignment(struct pci_dev *dev, int bar, - resource_size_t align) + resource_size_t align, bool resize) { struct resource *r = &dev->resource[bar]; resource_size_t size; @@ -5069,23 +5073,45 @@ static void pci_request_resource_alignment(struct pci_dev *dev, int bar, return; /* - * Increase the size of the resource. BARs are aligned on their - * size, so when we reallocate space for this resource, we'll - * allocate it with the larger alignment. It also prevents - * assignment of any other BARs inside the size. If we're - * requesting page alignment, this means no other BARs will share - * the page. + * Increase the alignment of the resource. There are two ways we + * can do this: * - * This makes the resource larger than the hardware BAR, which may - * break drivers that compute things based on the resource size, - * e.g., to find registers at a fixed offset before the end of the - * BAR. We hope users don't request alignment for such devices. + * 1) Increase the size of the resource. BARs are aligned on their + * size, so when we reallocate space for this resource, we'll + * allocate it with the larger alignment. This also prevents + * assignment of any other BARs inside the alignment region, so + * if we're requesting page alignment, this means no other BARs + * will share the page. + * + * The disadvantage is that this makes the resource larger than + * the hardware BAR, which may break drivers that compute things + * based on the resource size, e.g., to find registers at a + * fixed offset before the end of the BAR. + * + * 2) Retain the resource size, but use IORESOURCE_STARTALIGN and + * set r->start to the desired alignment. By itself this + * doesn't prevent other BARs being put inside the alignment + * region, but if we realign *every* resource of every device in + * the system, none of them will share an alignment region. + * + * When the user has requested alignment for only some devices via + * the "pci=resource_alignment" argument, "resize" is true and we + * use the first method. Otherwise we assume we're aligning all + * devices and we use the second. */ + dev_info(&dev->dev, "BAR%d %pR: requesting alignment to %#llx\n", bar, r, (unsigned long long)align); - r->start = 0; - r->end = align - 1; + if (resize) { + r->start = 0; + r->end = align - 1; + } else { + r->flags &= ~IORESOURCE_SIZEALIGN; + r->flags |= IORESOURCE_STARTALIGN; + r->start = align; + r->end = r->start + size - 1; + } r->flags |= IORESOURCE_UNSET; } @@ -5102,6 +5128,7 @@ void pci_reassigndev_resource_alignment(struct pci_dev *dev) struct resource *r; resource_size_t align; u16 command; + bool resize = false; /* * VF BARs are read-only zero according to SR-IOV spec r1.1, sec @@ -5113,7 +5140,7 @@ 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; @@ -5131,7 +5158,7 @@ void pci_reassigndev_resource_alignment(struct pci_dev *dev) pci_write_config_word(dev, PCI_COMMAND, command); for (i = 0; i <= PCI_ROM_RESOURCE; i++) - pci_request_resource_alignment(dev, i, align); + pci_request_resource_alignment(dev, i, align, resize); /* * Need to disable bridge's resource window, |
