Re: [PATCH v2 02/10] ppc: Remove stub of PPC970 HID4 implementation

[BALATON Zoltan]

On Tue, 7 Jan 2020, Greg Kurz wrote:
> On Tue, 7 Jan 2020 18:32:15 +0100
> Greg Kurz <address@hidden> wrote:
>
> > On Tue,  7 Jan 2020 15:48:19 +1100
> > David Gibson <address@hidden> wrote:
> >
> > > The PowerPC 970 CPU was a cut-down POWER4, which had hypervisor capability.
> > > However, it can be (and often was) strapped into "Apple mode", where the
> > > hypervisor capabilities were disabled (essentially putting it always in
> > > hypervisor mode).
>
> Isn't it supervisor mode instead of hypervisor mode ?

By the way, do you know if this strapping is hardware or software based? 
So is it the firmware that disables it on Apple hardware or is it some CPU 
pin connected somewhere on the motherboard or it's within the CPU and 
cannot be changed? I wonder if it's theoretically possible to re-enable it 
on an Apple G5 or we would likely never see a PowerPC 970 with HV enabled?

Regards,
BALATON Zoltan