Avi Kivity wrote:
quoted text > Gregory Haskins wrote:
>> Avi,
>>
>> Gregory Haskins wrote:
>> =20
>>> Todo:
>>> *) Develop some kind of hypercall registration mechanism for KVM so
>>> that
>>> we can use that as an integration point instead of directly hookin=
g
quoted text >>> kvm hypercalls
>>> =20
>>
>> What would you like to see here? I now remember why I removed the
>> original patch I had for registration...it requires some kind of
>> discovery mechanism on its own. Note that this is hard, but I figured=
quoted text >> it would make the overall series simpler if I didn't go this route and=
quoted text >> instead just integrated with a statically allocated vector. That bein=
g
quoted text >> said, I have no problem adding this back in but figure we should discu=
ss
quoted text >> the approach so I don't go down a rat-hole ;)
>>
>> =20
>
>
> One idea is similar to signalfd() or eventfd(). Provide a kvm ioctl
> that takes a gsi and returns an fd. Writes to the fd change the state
> of the line, possible triggering an interrupt. Another ioctl takes a
> hypercall number or pio port as well as an existing fd. Invocations
> of the hypercall or writes to the port write to the fd (using the same
> protocol as eventfd), so the other end can respond.
>
> The nice thing is that this can be used by both kernel and userspace
> components, and for kernel components, hypercalls can be either
> buffered or unbuffered.
And thus the "kvm-eventfd" (irqfd/iosignalfd) interface project was born.=
;)
(Michael FYI: so I will be pushing a vbus-v4 series at some point in the
near future that is expressed in terms of irqfd/iosignalfd, per the
conversation above. The patches in v3 and earlier are more intrusive to
the KVM core than they will be in final form)
-Greg
