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authorYuji Shimada <shimada-yxb@necst.nec.co.jp>2009-03-16 17:13:39 +0900
committerJesse Barnes <jbarnes@virtuousgeek.org>2009-03-20 10:48:15 -0700
commit32a9a682bef2f6fce7026bd94d1ce20028b0e52d (patch)
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parent1c8d7b0a562da06d3ebe83f01b1ed553205d1ae4 (diff)
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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: [<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...] 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. 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 <achiang@hp.com> Reviewed-by: Yu Zhao <yu.zhao@intel.com> Signed-off-by: Yuji Shimada <shimada-yxb@necst.nec.co.jp> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/kernel-parameters.txt9
1 files changed, 9 insertions, 0 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index c7c441e7930e..1754fedc531c 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1760,6 +1760,15 @@ and is between 256 and 4096 characters. It is defined in the file
cbmemsize=nn[KMG] The fixed amount of bus space which is
reserved for the CardBus bridge's memory
window. The default value is 64 megabytes.
+ resource_alignment=
+ Format:
+ [<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...]
+ 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.
pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
Management.