Re: [kvm-devel] [PATCH 10/13] KVM: Wire up hypercall handlers toa central arch-independent location

[Avi Kivity]

Arjan van de Ven wrote:
> > Somthing else that came up in a conversation with Dor: the need for a 
> > clean way to raise a guest interrupt.  The guest may be sleeping in 
> > userspace, scheduled out, or running on another cpu (and requiring an 
> > ipi to get it out of guest mode).
> >     
>
> yeah it'd be nice if I could just call a function for it rather than
> poking into kvm internals ;)
>
>   

Sure.  Please report all inconveniences (they're really bugs) so we can 
fix them.

Poking at kvm internals means you waste your time learning them, and 
later we can't change them.


> > Right now I'm thinking about using the signal machinery since it appears 
> > to do exactly the right thing.
> >     
>
> signals are *expensive* though.
>
>   

I think the expensive part of signals is userspace delivery.  If they 
are always blocked in userspace, they become just another IPC channel.

I plan to add a signal mask to KVM_RUN a la pselect() so that userspace 
can dequeue signals instead of using a signal handler.


> If you design an interrupt interface, it'd rock if you could make it
> such that it is "raise <this> interrupt within <x> miliseconds from
> now", rather than making it mostly synchronous. That way irq mitigation
> becomes part of the interface rather than having to duplicate it all
> over the virtual drivers...
>   

Can't it be done by a helper function using a timer and a signal (or 
whatever mechanism we use to wake up vcpus)?

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

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/