From 32a9a682bef2f6fce7026bd94d1ce20028b0e52d Mon Sep 17 00:00:00 2001 From: Yuji Shimada Date: Mon, 16 Mar 2009 17:13:39 +0900 Subject: PCI: allow assignment of memory resources with a specified alignment This patch allows memory resources to be assigned with a specified alignment at boot-time or run-time. The patch is useful when we use PCI pass-through, because page-aligned memory resources are required to securely share PCI resources with guest drivers. If you want to assign the resource at boot time, please set "pci=resource_alignment=" boot parameter. This is format of "pci=resource_alignment=" boot parameter: [@][:]:.[; ...] Specifies alignment and device to reassign aligned memory resources. If is not specified, PAGE_SIZE is used as alignment. PCI-PCI bridge can be specified, if resource windows need to be expanded. This is example: pci=resource_alignment=20@07:00.0;18@0f:00.0;00:1d.7 If you want to assign the resource at run-time, please set "/sys/bus/pci/resource_alignment" file, and hot-remove the device and hot-add the device. For this purpose, fakephp or PCI hotplug interfaces can be used. The format of "/sys/bus/pci/resource_alignment" file is the same with boot parameter. You can use "," instead of ";". For example: # cd /sys/bus/pci # echo -n 20@12:00.0 > resource_alignment # echo 1 > devices/0000:12:00.0/remove # echo 1 > rescan Reviewed-by: Alex Chiang Reviewed-by: Yu Zhao Signed-off-by: Yuji Shimada Signed-off-by: Jesse Barnes --- drivers/pci/quirks.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 60 insertions(+) (limited to 'drivers/pci/quirks.c') diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index 5aa2afb23ef..50233818a76 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -24,6 +24,7 @@ #include #include #include +#include #include "pci.h" int isa_dma_bridge_buggy; @@ -34,6 +35,65 @@ int pcie_mch_quirk; EXPORT_SYMBOL(pcie_mch_quirk); #ifdef CONFIG_PCI_QUIRKS +/* + * This quirk function disables the device and releases resources + * which is specified by kernel's boot parameter 'pci=resource_alignment='. + * It also rounds up size to specified alignment. + * Later on, the kernel will assign page-aligned memory resource back + * to that device. + */ +static void __devinit quirk_resource_alignment(struct pci_dev *dev) +{ + int i; + struct resource *r; + resource_size_t align, size; + + if (!pci_is_reassigndev(dev)) + return; + + if (dev->hdr_type == PCI_HEADER_TYPE_NORMAL && + (dev->class >> 8) == PCI_CLASS_BRIDGE_HOST) { + dev_warn(&dev->dev, + "Can't reassign resources to host bridge.\n"); + return; + } + + dev_info(&dev->dev, "Disabling device and release resources.\n"); + pci_disable_device(dev); + + align = pci_specified_resource_alignment(dev); + for (i=0; i < PCI_BRIDGE_RESOURCES; i++) { + r = &dev->resource[i]; + 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); + } + r->end = size - 1; + r->start = 0; + } + /* Need to disable bridge's resource window, + * to enable the kernel to reassign new resource + * window later on. + */ + if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE && + (dev->class >> 8) == PCI_CLASS_BRIDGE_PCI) { + for (i = PCI_BRIDGE_RESOURCES; i < PCI_NUM_RESOURCES; i++) { + r = &dev->resource[i]; + if (!(r->flags & IORESOURCE_MEM)) + continue; + r->end = resource_size(r) - 1; + r->start = 0; + } + pci_disable_bridge_window(dev); + } +} +DECLARE_PCI_FIXUP_HEADER(PCI_ANY_ID, PCI_ANY_ID, quirk_resource_alignment); + /* The Mellanox Tavor device gives false positive parity errors * Mark this device with a broken_parity_status, to allow * PCI scanning code to "skip" this now blacklisted device. -- cgit v1.2.3