[PATCH 18/19] KVM: PPC: Book3S HV: add passthrough support

[Benjamin Herrenschmidt]

On Wed, 2019-01-23 at 21:30 +1100, Paul Mackerras wrote:
> > Afaik bcs we change the mapping to point to the real HW irq ESB page
> > instead of the "IPI" that was there at VM init time.
> 
> So that makes it sound like there is a whole lot going on that hasn't
> even been hinted at in the patch descriptions...  It sounds like we
> need a good description of how all this works and fits together
> somewhere under Documentation/.
> 
> In any case we need much more informative patch descriptions.  I
> realize that it's all currently in Cedric's head, but I bet that in
> two or three years' time when we come to try to debug something, it
> won't be in anyone's head...

The main problem is understanding XIVE itself. It's not realistic to
ask Cedric to write a proper documentation for XIVE as part of the
patch series, but sadly IBM doesn't have a good one to provide either.

Ben.