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>
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