Ulrich Weigand wrote:
>
> Valery Brasseur wrote:
>
> > In the same way : did the guest OS know about the multi-cpu hardware ?
>
> No. To allow this would be a *lot* of effort: not only would we need
> to present emulated APICs and SMP-BIOS and whatnot to the guest, but
> also the various monitor algorithms would need to be MP safe, which
> makes things like 'lets change a descriptor table and trial-execute
> one instruction' rather impossible ...
Since there are a _lot_ of issues surrounding a VM which
offers a virtualized MP system, my thoughts are that we should
focus on a VM which offers only one virtualized processor for now.
I'd say at some point, after we get some OSes running, we should
look back at what we learned, and then decide if we want to
rewrite some componets of FreeMWare to handle more than
one virtualized processor. It should be more obvious then.
MP systems pose a ton of coherency issues, which will be
even worse to deal with in a VM environment, especially since we're
playing CPU tricks already.
We can however make use of an MP host, by spinning some
parts of the device emulation and GUI to other tasks.
The host can then schedule these tasks across multiple
processors as it sees fits.
-Kevin
