Re: [Xen-devel] [PATCH v3] xen: introduce VCPUOP_register_runstate_phys_memory_area hypercall

[Andrii Anisov <andrii.anisov@xxxxxxxxx>]

Hello Jan,

On 17.06.19 09:28, Jan Beulich wrote:
> > We may require existing runstate area unregistering if the system is aware
> > of it. But it is for the new interface.
> > The old one has no documentation about the unregistering. The implicit way
> > is known to us, but not known to users.
> > How to solve the clash?
> And once again I'm not sure what to answer, considering that I've
> already outlined a possible model (without any explicit unregistration).
Just to be sure, "the model" you are talking about is following:

> I thought it had been clarified already that normal guests can very
> well use both interfaces, just not both at the same time: Boot loader
> and OS could disagree in this regard, as the prime example.
Is it correct?

But with the current interface (VA) that model is already broken without 
unregistration. On change between entities with different VA spaces the 
hypervisor definitely has a chance to spoil the new VA space at the old address.
IMHO it should be fixed (at least documented) for the old interface.

--
Sincerely,
Andrii Anisov.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel