io_emul: remove pending_pre_work

Now we do not need pending_pre_work anymore, as we can make sure IO request
VCPU resume from where it paused.

Now only three fixed points will try to do schedule:
- vcpu_thread: before vm entry, will check reschedule flag and to it if needed
- default_idle: loop check reschedule flag to see if need switch out
- io request: if IO REQ need DM's handle, it will schedule out

Tracked-On: #2394
Signed-off-by: Jason Chen CJ <jason.cj.chen@intel.com>
Acked-by: Xu, Anthony <anthony.xu@intel.com>

hypervisor/include/arch/x86/guest/vcpu.h

@@ -13,8 +13,6 @@
 #ifndef VCPU_H
 #define VCPU_H
 
-#define	ACRN_VCPU_MMIO_COMPLETE		(0U)
-
 /* Number of GPRs saved / restored for guest in VCPU structure */
 #define NUM_GPRS                            16U
 #define GUEST_STATE_AREA_SIZE               512
@@ -274,7 +272,6 @@ struct acrn_vcpu {
 	uint64_t sync;	/*hold the bit events*/
 
 	struct sched_object sched_obj;
-	uint64_t pending_pre_work; /* any pre work pending? */
 	bool launched; /* Whether the vcpu is launched on target pcpu */
 	uint32_t paused_cnt; /* how many times vcpu is paused */
 	uint32_t running; /* vcpu is picked up and run? */
@@ -606,8 +603,6 @@ void schedule_vcpu(struct acrn_vcpu *vcpu);
  */
 int32_t prepare_vcpu(struct acrn_vm *vm, uint16_t pcpu_id);
 
-void request_vcpu_pre_work(struct acrn_vcpu *vcpu, uint16_t pre_work_id);
-
 /**
  * @}
  */