HV: Using INIT to kick vCPUs off when RTVM poweroff by itself

When RTVM is trying to poweroff by itself, we use INIT to
kick vCPUs off the non-root mode.

For RTVM, only if vm state equal VM_POWERING_OFF, we take action to pause
the vCPUs with INIT signal. Otherwise, we will reject the pause request.

Tracked-On: #2865
Signed-off-by: Kaige Fu <kaige.fu@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>

Author: KaigeFu

hypervisor/arch/x86/guest/vcpu.c

@@ -598,7 +598,13 @@ void pause_vcpu(struct acrn_vcpu *vcpu, enum vcpu_state new_state)
 
 	if (atomic_load32(&vcpu->running) == 1U) {
 		remove_from_cpu_runqueue(&vcpu->sched_obj, vcpu->pcpu_id);
-		make_reschedule_request(vcpu->pcpu_id, DEL_MODE_IPI);
+
+		if (is_lapic_pt(vcpu->vm)) {
+			make_reschedule_request(vcpu->pcpu_id, DEL_MODE_INIT);
+		} else {
+			make_reschedule_request(vcpu->pcpu_id, DEL_MODE_IPI);
+		}
+
 		release_schedule_lock(vcpu->pcpu_id);
 
 		if (vcpu->pcpu_id != pcpu_id) {

hypervisor/arch/x86/guest/vm.c

@@ -547,10 +547,21 @@ void pause_vm(struct acrn_vm *vm)
 	struct acrn_vcpu *vcpu = NULL;
 
 	if (vm->state != VM_PAUSED) {
-		vm->state = VM_PAUSED;
+		if (is_rt_vm(vm)) {
+			/* Only when RTVM is powering off by itself, we can pause vcpu */
+			if (vm->state == VM_POWERING_OFF) {
+				foreach_vcpu(i, vm, vcpu) {
+					pause_vcpu(vcpu, VCPU_ZOMBIE);
+				}
 
-		foreach_vcpu(i, vm, vcpu) {
-			pause_vcpu(vcpu, VCPU_ZOMBIE);
+				vm->state = VM_PAUSED;
+			}
+		} else {
+			foreach_vcpu(i, vm, vcpu) {
+				pause_vcpu(vcpu, VCPU_ZOMBIE);
+			}
+
+			vm->state = VM_PAUSED;
 		}
 	}
 }

hypervisor/arch/x86/guest/vmexit.c

@@ -28,6 +28,7 @@ static int32_t unhandled_vmexit_handler(struct acrn_vcpu *vcpu);
 static int32_t xsetbv_vmexit_handler(struct acrn_vcpu *vcpu);
 static int32_t wbinvd_vmexit_handler(struct acrn_vcpu *vcpu);
 static int32_t undefined_vmexit_handler(struct acrn_vcpu *vcpu);
+static int32_t init_signal_vmexit_handler(__unused struct acrn_vcpu *vcpu);
 
 /* VM Dispatch table for Exit condition handling */
 static const struct vm_exit_dispatch dispatch_table[NR_VMX_EXIT_REASONS] = {
@@ -38,7 +39,7 @@ static const struct vm_exit_dispatch dispatch_table[NR_VMX_EXIT_REASONS] = {
 	[VMX_EXIT_REASON_TRIPLE_FAULT] = {
 		.handler = unhandled_vmexit_handler},
 	[VMX_EXIT_REASON_INIT_SIGNAL] = {
-		.handler = unhandled_vmexit_handler},
+		.handler = init_signal_vmexit_handler},
 	[VMX_EXIT_REASON_STARTUP_IPI] = {
 		.handler = unhandled_vmexit_handler},
 	[VMX_EXIT_REASON_IO_SMI] = {
@@ -343,3 +344,21 @@ static int32_t undefined_vmexit_handler(struct acrn_vcpu *vcpu)
 	vcpu_inject_ud(vcpu);
 	return 0;
 }
+
+/*
+ * This handler is only triggered by INIT signal when poweroff from inside of RTVM
+ */
+static int32_t init_signal_vmexit_handler(__unused struct acrn_vcpu *vcpu)
+{
+	/*
+	 * Intel SDM Volume 3, 25.2:
+	 *   INIT signals. INIT signals cause VM exits. A logical processer performs none
+	 *   of the operations normally associated with these events. Such exits do not modify
+	 *   register state or clear pending events as they would outside of VMX operation (If
+	 *   a logical processor is the wait-for-SIPI state, INIT signals are blocked. They do
+	 *   not cause VM exits in this case).
+	 *
+	 * So, it is safe to ignore the signal and reture here.
+	 */
+	return 0;
+}