Quote: I note our German maintainers have been conspicuously quiet

Allright, so here's the short answer to the original question. You can
build the kernel with either a tape or
a card reader boot loader. When you IPL that, it gets loaded into guest
real memory starting from address
0. However, if you use zipl to prepare a disk, the boot code will skip the
first 64k and start loading the
rest of the kernel above 64k. When the kernel starts up, it will allocate
addional memory for its purposes
such as memory management or task management data structures, and also for
loadable kernel modules.
At the same time, it will free up memory during startup like kernel
functions that are only used for
initialization (kernel message: "freeing bootmem"). The resulting footprint
for both kernel binary code and
its data structures will be spread over the guest real address space, with
a big chunk being the kernel text
section starting at 64k ending at about 5meg depending on your kernel
configuration.

Since this guest real address space is seperate from both the application
address spaces and the LPAR/VM
hypervisor address spaces it does not matter to either an application
and/or a hypervisor where the kernel
and its data structures are located in memory.


with kind regards
Carsten Otte
IBM Linux Technology Center / Boeblingen lab
--
omnis enim res, quae dando non deficit, dum habetur et non datur, nondum
habetur, quomodo habenda est

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