Probing for native availability of isel from userspace

[Kumar Gala]

On Sep 25, 2012, at 3:59 PM, Benjamin Herrenschmidt wrote:

> On Tue, 2012-09-25 at 15:17 +0200, Segher Boessenkool wrote:
>>>> Fine. But I believe that mfpvr emulation came first, which is the  
>>>> point
>>>> I object to (see the mess that the fact that CPUID is available to
>>>> applications made to x86 when SSE registers were added).
>>> 
>>> Heh, possibly, I don't remember... I added the cputable, I think we
>>> added mfpvr because we didn't have anything, then I added cputable  
>>> which
>>> got us the HW caps, but some old stuff still relied on mfpvr so we
>>> couldn't completely remove it.
>> 
>> If I have my history right end up, MFPVR emulation was added for MoL.
>> Which is funny (if you like that kind of thing) because it now hurts
>> all other "hypervisor in userspace" kind of things, that might want
>> to lie in their emulated PVR...
> 
> Are you sure ? MOL had a kernel module, it wouldn't have needed that...

I feel like there was some JVMs (IBMs?) that used MFPVR to determine some things.

- k