[SeaBIOS] vgabios -> seabios breaks (my) 16-bit applications

[Paolo Bonzini]

> > No, KVM hides the fact that you are in protected mode.  EMM386 would be
> > affected, but then it is not impossible for old programs to require
> > disabling it.
> 
> I was under the vague impression that kvm uses VM86 mode to run 16bit
> code on some Intel chipsets.  The SMSW instruction isn't privileged so
> I didn't think it could be hidden.

It isn't privileged indeed (nice trick in fact!), but that doesn't matter
for VT-x extensions.

Old processors let you run the processor in VMX non-root mode (i.e. as a VM)
only in protected mode, so KVM uses VM86 when the processor is in real mode
(and uses an interpreter while in big real mode or during real<->protected mode
transitions).

But all the bells and whistles of VMX still apply, including the ability to
fake the value of CR0 for both MOV and [LS]MSW instructions.

Paolo