Hi Petr,
You're preaching to the choir, man...
[PATCH 00/10] Enhance /dev/mem to allow read/write of arbitrary physical addresses
https://lkml.org/lkml/2011/6/17/81
and especially your response to Ingo:
https://lkml.org/lkml/2011/6/17/106
I fought and lost that war within Red Hat years ago, but I wish you
the best of luck!
Thanks,
Dave