forked from mirror/qemu
You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
55 lines
1.9 KiB
ReStructuredText
55 lines
1.9 KiB
ReStructuredText
..
|
|
Copyright (c) 2020, Linaro
|
|
|
|
Guest Loader
|
|
------------
|
|
|
|
The guest loader is similar to the ``generic-loader`` although it is
|
|
aimed at a particular use case of loading hypervisor guests. This is
|
|
useful for debugging hypervisors without having to jump through the
|
|
hoops of firmware and boot-loaders.
|
|
|
|
The guest loader does two things:
|
|
|
|
- load blobs (kernels and initial ram disks) into memory
|
|
- sets platform FDT data so hypervisors can find and boot them
|
|
|
|
This is what is typically done by a boot-loader like grub using it's
|
|
multi-boot capability. A typical example would look like:
|
|
|
|
.. parsed-literal::
|
|
|
|
|qemu_system| -kernel ~/xen.git/xen/xen \
|
|
-append "dom0_mem=1G,max:1G loglvl=all guest_loglvl=all" \
|
|
-device guest-loader,addr=0x42000000,kernel=Image,bootargs="root=/dev/sda2 ro console=hvc0 earlyprintk=xen" \
|
|
-device guest-loader,addr=0x47000000,initrd=rootfs.cpio
|
|
|
|
In the above example the Xen hypervisor is loaded by the -kernel
|
|
parameter and passed it's boot arguments via -append. The Dom0 guest
|
|
is loaded into the areas of memory. Each blob will get
|
|
``/chosen/module@<addr>`` entry in the FDT to indicate it's location and
|
|
size. Additional information can be passed with by using additional
|
|
arguments.
|
|
|
|
Currently the only supported machines which use FDT data to boot are
|
|
the ARM and RiscV ``virt`` machines.
|
|
|
|
Arguments
|
|
^^^^^^^^^
|
|
|
|
The full syntax of the guest-loader is::
|
|
|
|
-device guest-loader,addr=<addr>[,kernel=<file>,[bootargs=<args>]][,initrd=<file>]
|
|
|
|
``addr=<addr>``
|
|
This is mandatory and indicates the start address of the blob.
|
|
|
|
``kernel|initrd=<file>``
|
|
Indicates the filename of the kernel or initrd blob. Both blobs will
|
|
have the "multiboot,module" compatibility string as well as
|
|
"multiboot,kernel" or "multiboot,ramdisk" as appropriate.
|
|
|
|
``bootargs=<args>``
|
|
This is an optional field for kernel blobs which will pass command
|
|
like via the ``/chosen/module@<addr>/bootargs`` node.
|