[Qemu-discuss] Impact of incorrectly-mapped OVMF

[Prerna]

Hi all,
In playing around with OVMF a few times I accidentally specified my
qemu-kvm binary with this erroneous command line: "qemu-kvm ... -bios
/usr/share/OVMF/OVMF_CODE.fd" instead of passing this as if=pflash.

I was expecting this to error out in qemu, but surprisingly qemu(2.6) let
the VM boot into EDK2 shell, and even past that into the VM's cdrom that
ran an installer.  Ofcourse the VM would sporadically see odd hangs/crashes
but that would always happen at a different time instant (sometimes not
happening for even days).

My question is, what happens from a firmware initialisation perspective if
edk2 is passed as a bios rom instead of as pflash? Also, given that all
these are effectively blobs that load into memory, is there some sort of
pre-check that can be done by QEMU to avoid loading OVMF binary as a bios
ROM ?

(Note that this is purely out of curiosity, I understand it is risky to run
this in production)

Regards,
Prerna