On UEFI UP2 board, APs might execute HLT before SOS kernel INIT them.
After SOS kernel take over and will re-init the APs directly. The flows
from HV perspective is like:
HLT trap:
wait_event(VCPU_EVENT_VIRTUAL_INTERRUPT) -> sleep_thread
SOS kernel INIT, SIPI APs:
pause_vcpu(ZOMBIE) -> sleep_thread
-> reset_vcpu
-> launch_vcpu -> wake_vcpu
However, the last wake_vcpu will fail because the cpu event
VCPU_EVENT_VIRTUAL_INTERRUPT had not got signaled.
This patch will reset all vcpu events in reset_vcpu. If the thread was
previously waiting for a event, its waiting status will be cleared and
launch_vcpu will wake it to running.
Tracked-On: #4402
Signed-off-by: Shuo A Liu <shuo.a.liu@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
This simple event implemention can only support exclusive waiting
at same time. It mainly used by thread who want to wait for special event
happens.
Thread A who want to wait for some events calls
wait_event(struct sched_event *);
Thread B who can give the event signal calls
signal_event(struct sched_event *);
Tracked-On: #4329
Signed-off-by: Shuo A Liu <shuo.a.liu@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
Shuo A Liu