Re: [RFC kvm-unit-tests PATCH] powerpc: add tests for XICS

[Benjamin Herrenschmidt <benh@au1.ibm.com>]

On Wed, 2017-11-22 at 13:39 +0100, Laurent Vivier wrote:
> These errors can be fixed by two different ways:
> 
> A- don't allow set-xive to set the priority to 255 (the MASKED value)
>    and return an error value, and get-xive return an error value if
>    priority is the MASKED value
> 
> B- store the server in set-xive even it the value is the MASKED one, so
> we can get it with get-xive and use it with int-on (with the saved
> priority value)
> 
> (A) follows the specs:
> 
> Linux on Power Architecture Platform Reference,  v1.1
> R1–7.3.10.2–5. For the PowerPC External Interrupt option: The
>                ibm,set-xive call must return the Status of -3
>                (Argument Error) for an unimplemented Interrupt number.
> 
> (B) would behave like XICS with P8 and TCG.
> 
> Any ideas?

I don't see much point in supporting an unbalance where somebody
masks with set_xive and unmasks with int_on...

These PAPR APIs originates from pre-historical times, it's a bit
of a mess.

set_xive should be able to set a priority of 255, that's a
requirement, but we could fix the emulation to store the server
in that case I suppose.


Ben.