This patch adds vm_event sbuf and notification initialization.
We have 2 types of event source: DM and HV, and they are slightly
different:
- Sbuf for DM event source is a memery page shared between threads.
Event notifications are delivered by userspace eventfd.
- While for hv event source, sbuf is a memery page shared with HV. Its
address(GPA) is shared to HV through hypercall. Its notifications
are generated by HV upcall, then delivered by kernel/userspace eventfd.
A sbuf message path acts like a one way ‘tunnel’, so a data structure
‘vm_event_tunnel’ is created to organize those sbufs.
Tracked-On: #8547
Signed-off-by: Wu Zhou <wu.zhou@intel.com>
Reviewed-by: Jian Jun Chen <jian.jun.chen@intel.com>