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Andre Przywara
a8992d6236
Currently we use the chosen/bootargs property as the Xen commandline and rely on xen,dom0-bootargs for Dom0. However this brings issues with bootloaders, which usually build bootargs by bootscripts for a Linux kernel - and not for the entirely different Xen hypervisor. Introduce a new possible device tree property "xen,xen-bootargs" explicitly for the Xen hypervisor and make the selection of which to use more fine grained: - If xen,xen-bootargs is present, it will be used for Xen. - If xen,dom0-bootargs is present, it will be used for Dom0. - If xen,xen-bootargs is _not_ present, but xen,dom0-bootargs is, bootargs will be used for Xen. Like the current situation. - If no Xen specific properties are present, bootargs is for Dom0. - If xen,xen-bootargs is present, but xen,dom0-bootargs is missing, bootargs will be used for Dom0. The aim is to allow common bootscripts to boot both Xen and native Linux with the same device tree blob. If needed, one could hard-code the Xen commandline into the DTB, leaving bootargs for Dom0 to be set by the (non Xen-aware) bootloader. I will send out a appropriate u-boot patch, which writes the content of the "xen_bootargs" environment variable into the xen,xen-bootargs dtb property. Signed-off-by: Andre Przywara <andre.przywara@linaro.org> Signed-off-by: Julien Grall <julien.grall@linaro.org> Acked-by: Ian Campbell <ian.campbell@citrix.com>
52 lines
1.6 KiB
Plaintext
52 lines
1.6 KiB
Plaintext
Dom0 kernel and ramdisk modules
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Xen is passed the dom0 kernel and initrd via a reference in the /chosen
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node of the device tree.
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Each node has the form /chosen/modules/module@<N> and contains the following
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properties:
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- compatible
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Must be:
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"xen,<type>", "xen,multiboot-module"
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where <type> must be one of:
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- "linux-zimage" -- the dom0 kernel
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- "linux-initrd" -- the dom0 ramdisk
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- reg
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Specifies the physical address of the module in RAM and the
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length of the module.
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- bootargs (optional)
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Command line associated with this module. This is deprecated and should
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be replaced by the bootargs variations described below.
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Command lines
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=============
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Xen also checks for properties directly under /chosen to find suitable command
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lines for Xen and Dom0. The logic is the following:
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- If xen,xen-bootargs is present, it will be used for Xen.
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- If xen,dom0-bootargs is present, it will be used for Dom0.
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- If xen,xen-bootargs is _not_ present, but xen,dom0-bootargs is,
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bootargs will be used for Xen.
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- If no Xen specific properties are present, bootargs is for Dom0.
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- If xen,xen-bootargs is present, but xen,dom0-bootargs is missing,
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bootargs will be used for Dom0.
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Most of these cases is to make booting with Xen-unaware bootloaders easier.
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For those you would hardcode the Xen commandline in the DTB under
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/chosen/xen,xen-bootargs and would let the bootloader set the Dom0 command
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line by writing bootargs (as for native Linux).
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A Xen-aware bootloader would set xen,xen-bootargs for Xen, xen,dom0-bootargs
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for Dom0 and bootargs for native Linux.
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