Initial CPU state

[Amjad50]

I noticed in UEFI and BIOS, the state of the CPU is different, namely the MSR and C0,4 registers.
for example, as of writing this issue, with UEFI, the kernel cannot write to protected user pages, but with BIOS it can. (tested in qemu only).
Which resulted in a crash in the ELF loader for UEFI, because we are writing to a read-only user pages.

Would be good to have a standard known from boot which features we have support for.