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qemu/docs/system/guest-loader.rst

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docs: add some documentation for the guest-loader Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Alistair Francis <alistair.francis@wdc.com> Message-Id: <20210303173642.3805-7-alex.bennee@linaro.org>
2021-03-03 20:36:41 +03:00
..
Copyright (c) 2020, Linaro
Guest Loader
------------
docs: Format literals correctly In rST markup, single backticks `like this` represent "interpreted text", which can be handled as a bunch of different things if tagged with a specific "role": https://docutils.sourceforge.io/docs/ref/rst/restructuredtext.html#interpreted-text (the most common one for us is "reference to a URL, which gets hyperlinked"). The default "role" if none is specified is "title_reference", intended for references to book or article titles, and it renders into the HTML as <cite>...</cite> (usually comes out as italics). This commit fixes various places in the manual which were using single backticks when double backticks (for literal text) were intended, and covers those files where only one or two instances of these errors were made. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2021-07-26 17:23:36 +03:00
The guest loader is similar to the ``generic-loader`` although it is
docs: add some documentation for the guest-loader Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Alistair Francis <alistair.francis@wdc.com> Message-Id: <20210303173642.3805-7-alex.bennee@linaro.org>
2021-03-03 20:36:41 +03:00
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
docs: Format literals correctly In rST markup, single backticks `like this` represent "interpreted text", which can be handled as a bunch of different things if tagged with a specific "role": https://docutils.sourceforge.io/docs/ref/rst/restructuredtext.html#interpreted-text (the most common one for us is "reference to a URL, which gets hyperlinked"). The default "role" if none is specified is "title_reference", intended for references to book or article titles, and it renders into the HTML as <cite>...</cite> (usually comes out as italics). This commit fixes various places in the manual which were using single backticks when double backticks (for literal text) were intended, and covers those files where only one or two instances of these errors were made. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2021-07-26 17:23:36 +03:00
``/chosen/module@<addr>`` entry in the FDT to indicate it's location and
docs: add some documentation for the guest-loader Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Alistair Francis <alistair.francis@wdc.com> Message-Id: <20210303173642.3805-7-alex.bennee@linaro.org>
2021-03-03 20:36:41 +03:00
size. Additional information can be passed with by using additional
arguments.
Currently the only supported machines which use FDT data to boot are
docs: Format literals correctly In rST markup, single backticks `like this` represent "interpreted text", which can be handled as a bunch of different things if tagged with a specific "role": https://docutils.sourceforge.io/docs/ref/rst/restructuredtext.html#interpreted-text (the most common one for us is "reference to a URL, which gets hyperlinked"). The default "role" if none is specified is "title_reference", intended for references to book or article titles, and it renders into the HTML as <cite>...</cite> (usually comes out as italics). This commit fixes various places in the manual which were using single backticks when double backticks (for literal text) were intended, and covers those files where only one or two instances of these errors were made. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2021-07-26 17:23:36 +03:00
the ARM and RiscV ``virt`` machines.
docs: add some documentation for the guest-loader Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Alistair Francis <alistair.francis@wdc.com> Message-Id: <20210303173642.3805-7-alex.bennee@linaro.org>
2021-03-03 20:36:41 +03:00
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.
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