Re: [PATCH] KVM: Introduce dynamically registered hypercall capability

["Radim Krčmář" <rkrcmar@redhat.com>]

2014-11-27 05:30-0800, Phil White:
> This introduces a list of entries which associate a function pointer of
> kvm_hc_type to a hypercall number and allows the ability to register and
> unregister entries.  In addition, it also allows the ability to retrieve a
> function pointer of kvm_hc_type for a given hypercall number which is meant
> to be called from the arch-specific section.
> 
> The main intent is to allow modules to register hypercalls which they own
> rather than requiring the addition of a stub of some sort.  It will also
> allow each arch to maintain separate lists of hypercalls rather than having
> to respect changes in include/uapi/linux/kvm_para.h
> 
> Signed-off-by: Phil White <pwhite@mvista.com>
> ---

Apart from other problems,
how are guests going to use these hypercalls?

(If hc_nr is dynamic, a guest doesn't know its number and even if it is
 static, someone could have registered it beforehand => this needs some
 kind of synchronization with host modules.  A hardcoded reservation?)