On 06/26/2010 02:25 AM, Alexander Graf wrote:

We just introduced a new PV interface that screams for documentation. So here
it is - a shiny new and awesome text file describing the internal works of
the PPC KVM paravirtual interface.


+Querying for existence
+======================
+
+To find out if we're running on KVM or not, we overlay the PVR register. Usually
+the PVR register contains an id that identifies your CPU type. If, however, you
+pass KVM_PVR_PARA in the register that you want the PVR result in, the register
+still contains KVM_PVR_PARA after the mfpvr call.
+
+	LOAD_REG_IMM(r5, KVM_PVR_PARA)
+	mfpvr	r5
+	[r5 still contains KVM_PVR_PARA]
+
+Once determined to run under a PV capable KVM, you can now use hypercalls as
+described below.
   

On x86 we allow host userspace to determine whether the guest sees the 
paravirt interface (and what features are exposed).  This allows you to 
live migrate from a newer host to an older host, by not exposing the 
newer features.

-- 
error compiling committee.c: too many arguments to function