Re: [PATCH 19/23] KVM: PPC: Book3S: Select PR vs HV separately for each guest

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

On Fri, 2013-09-13 at 10:17 +1000, Paul Mackerras wrote:

> Aneesh and I are currently investigating an alternative approach,
> which is much more like the x86 way of doing things.  We are looking
> at splitting the code into three modules: a kvm_pr.ko module with the
> PR-specific bits, a kvm_hv.ko module with the HV-specific bits, and a
> core kvm.ko module with the generic bits (basically book3s.c,
> powerpc.c, stuff from virt/kvm/, plus the stuff that both PR and HV
> use).  Basically the core module would have a pointer to a struct
> full of function pointers for the various ops that book3s_pr.c and
> book3s_hv.c both provide.  You would only be able to have one of
> kvm_pr and kvm_hv loaded at any one time.  If they were built in, you
> could have them both built in but only one could register its function
> pointer struct with the core.  Obviously the kvm_hv module would only
> load and register its struct on a machine that had hypervisor mode
> available.  If they were both built in I would think we would give HV
> the first chance to register itself, and let PR register if we can't
> do HV.
> 
> How does that sound?

As long as we can force-load the PR one on a machine that normally runs
HV for the sake of testing ...

Also, all those KVM modules ... they don't auto-load do they ?

Cheers,
Ben.