Re: XEN...if ever?
On Wed, Apr 12, 2006 at 02:22:40PM +1000, Aaron Kerr wrote:
> I really some of this porting effort produces something that is G4
First avoid posting in Hideous Trash Makeup Language, thanks.
Second, there is no hope of making Xen work on the existing
G4. The hypervisor support is equivalent to a third privilege
level in the processor. The G4 only has two privilege levels,
and I can't think of an efficient way of emulating a third
level (you'd have to run the OS in user mode).
For the record, x86 is not the only architecture with more
than 2 privilege levels, Vaxes had 4 or 5 25 years ago, ia64
and I believe hppa also have at least 4 privilege levels.
However the x86 implementation is so impractical (the processor
is not fully virtualizable) that Intel and AMD recently added
level, very similar to an hypervisor state, that should allow
full processor virtualization. This is in addition to SMM
that was added a long time ago and turned out to be a
nightmare in some cases (some functions emulated by
SMM have a very long latency).