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

[David Gibson]

On Tue, Jan 07, 2020 at 07:05:41PM +0100, BALATON Zoltan wrote:
> 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?

I don't know, sorry.

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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