Re: [Qemu-devel] OT: Running qemu without host os?

[Mark Williamson]

> > Unless all of the guest OSes were modified to be aware that they were
> > sharing hardware (or else some really intelligent dynamic patching was
> > going on), the OSes would step all over eachother.  For instance, one
> > guest OS might put the NIC in promiscuous mode right before another
> > guest OS boots and re-initializes the NIC to non-promiscuous mode.  A
> > third guest OS might then change the MAC address on the NIC and screw
> > up ARP.
>
> Isn't that what xen does? All guest OSes has to be modified to run.

In a situation where you want multiple guests to directly control different 
bits of the hardware, Xen can hide all the "irrelevant" hardware from a guest 
so that it won't tread on other guests' devices.  This technique would be 
applicable to a hypothetical "qemu on bare metal" as well.

Cheers,
Mark