Problem loading linux 5.19 as PV dom0

[Juergen Gross <jgross@xxxxxxxx>]

A Linux kernel 5.19 can only be loaded as dom0, if it has been
built with CONFIG_AMD_MEM_ENCRYPT enabled. This is due to the
fact that otherwise the (relevant) last section of the built
kernel has the NOLOAD flag set (it is still marked with
SHF_ALLOC).

I think at least the hypervisor needs to be changed to support
this layout. Otherwise it will put the initial page tables for
dom0 at the same position as this last section, leading to
early crashes.

A workaround in the kernel would be to always add a small
section at the end which needs to be loaded (like is done
with CONFIG_AMD_MEM_ENCRYPT set), but I don't think we can
put this burden on all guests being capable to run in PV
mode.

I haven't tested yet, whether unprivileged PV guests are
affected, too.


Juergen

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