[SeaBIOS] [Qemu-devel] seabios serial console vs. sgabios

[Gerd Hoffmann]

  Hi,

> > Hmm, why?  The user asked for a serial console.  Whenever that is
> > provided by seabios builtin support or the sgabios rom doesn't
> > really
> > matter, no?
> 
> Surely it has ABI implications for the guest if we stop putting the
> sgabios option ROM into memory - changing layout of ROMS

Because of that changing -device sga behavior on the qemu side must be
tied to the qemu machine type.

> > Also, the question is what seabios should do in case both are
> > active. 
> > Which I think can happen today with libvirt if you configure a
> > virtual
> > machine without vga (libvirt passes -machine graphics=off which
> > activates builtin serial console) and with "<bios
> > useserial='yes'/>"
> > (enables sgabios rom).
> 
> Libvirt doesn't use  '-machine graphics=off' AFAIK, only '-
> nographic'.

I think that is pretty much the same.  Setting "graphichs=off" is one
of the effects of passing -nographic, and the other effects (like
setting up default serial + monitor in a different way) don't happen
due to libvirt also using -nodefaults.

cheers,
  Gerd