Hypervisor <-> dom0 userspace event channel

Hypervisor <-> dom0 userspace event channel

[Razvan Cojocaru]

Hello,

if the goal is establishing an event channel between the Xen HV and a
custom dom0 userspace application,

1. for the hypervisor code, would you recommend using the EVTCHNOP_*
hypercalls from xen/include/public/event_channel.h directly, or the
friendlier xen/include/xen/event.h functions? And for the userspace
tool, I'd use the xenctrl.h xc_evtchn_*() functions, correct?

2. what would be the best way of exposing the hypervisor event channel
port received from alloc_unbound_xen_event_channel() to the dom0
userspace application? Put it somewhere in the shared info page? I'm
assuming the XenStore is out of the question for this purpose, and
otherwise overkill.

3. what is the best way (most efficient, and Xen-friendly way) of
exposing HV data such as event channel ports or shared page mfns/pfns to
a custom dom0 userspace application?

Thanks,
Razvan