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/arch/x86/guest/vcpu.c

@@ -383,7 +383,6 @@ int32_t create_vcpu(uint16_t pcpu_id, struct acrn_vm *vm, struct acrn_vcpu **rtn
 	vcpu->paused_cnt = 0U;
 	vcpu->running = 0;
 	vcpu->arch.nr_sipi = 0;
-	vcpu->pending_pre_work = 0U;
 	vcpu->state = VCPU_INIT;
 
 	reset_vcpu_regs(vcpu);
@@ -535,7 +534,6 @@ void reset_vcpu(struct acrn_vcpu *vcpu)
 	vcpu->paused_cnt = 0U;
 	vcpu->running = 0;
 	vcpu->arch.nr_sipi = 0;
-	vcpu->pending_pre_work = 0U;
 
 	vcpu->arch.exception_info.exception = VECTOR_INVALID;
 	vcpu->arch.cur_context = NORMAL_WORLD;
@@ -679,8 +677,3 @@ int32_t prepare_vcpu(struct acrn_vm *vm, uint16_t pcpu_id)
 
 	return ret;
 }
-
-void request_vcpu_pre_work(struct acrn_vcpu *vcpu, uint16_t pre_work_id)
-{
-	bitmap_set_lock(pre_work_id, &vcpu->pending_pre_work);
-}

hypervisor/arch/x86/io_emul.c

@@ -146,18 +146,7 @@ void emulate_io_post(struct acrn_vcpu *vcpu)
 		} else {
 			switch (vcpu->req.type) {
 			case REQ_MMIO:
-				/*
-				 * In IO completion polling mode, the post work of IO emulation will
-				 * be running on its own pcpu, then we can do MMIO post work directly;
-				 * While in notification mode, the post work of IO emulation will be
-				 * running on SOS pcpu, then we need request_vcpu_pre_work and let
-				 * its own pcpu get scheduled and finish the MMIO post work.
-				 */
-				if (!vcpu->vm->sw.is_completion_polling) {
-					request_vcpu_pre_work(vcpu, ACRN_VCPU_MMIO_COMPLETE);
-				} else {
 				dm_emulate_mmio_post(vcpu);
-				}
 				break;
 
 			case REQ_PORTIO:

hypervisor/common/hv_main.c

@@ -8,23 +8,12 @@
 #include <schedule.h>
 #include <softirq.h>
 
-static void run_vcpu_pre_work(struct acrn_vcpu *vcpu)
-{
-	uint64_t *pending_pre_work = &vcpu->pending_pre_work;
-
-	if (bitmap_test_and_clear_lock(ACRN_VCPU_MMIO_COMPLETE, pending_pre_work)) {
-		dm_emulate_mmio_post(vcpu);
-	}
-}
-
 void vcpu_thread(struct sched_object *obj)
 {
 	struct acrn_vcpu *vcpu = list_entry(obj, struct acrn_vcpu, sched_obj);
 	uint32_t basic_exit_reason = 0U;
 	int32_t ret = 0;
 
-	run_vcpu_pre_work(vcpu);
-
 	do {
 		/* If vcpu is not launched, we need to do init_vmcs first */
 		if (!vcpu->launched) {
@@ -46,15 +35,7 @@ void vcpu_thread(struct sched_object *obj)
 		}
 
 		if (need_reschedule(vcpu->pcpu_id)) {
-			/*
-			 * In extrem case, schedule() could return. Which
-			 * means the vcpu resume happens before schedule()
-			 * triggered by vcpu suspend. In this case, we need
-			 * to do pre work and continue vcpu loop after
-			 * schedule() is return.
-			 */
 			schedule();
-			run_vcpu_pre_work(vcpu);
 			continue;
 		}
 

hypervisor/common/io_req.c

@@ -154,6 +154,8 @@ int32_t acrn_insert_request_wait(struct acrn_vcpu *vcpu, const struct io_request
 				}
 				asm_pause();
 			}
+		} else if (need_reschedule(vcpu->pcpu_id)) {
+			schedule();
 		}
 		ret = 0;
 	} else {

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);
-
 /**
  * @}
  */