hv: implement NEED_SHUTDOWN_VM request to idle thread

For pre-launched VMs and SOS, VM shutdown should not be executed in the
current VM context.

- implement NEED_SHUTDOWN_VM request so that the BSP of the target VM can shut
  down the guest in idle thread.
- implement shutdown_vm_from_idle() to shut down target VM.

Tracked-On: #2700
Signed-off-by: Zide Chen <zide.chen@intel.com>
Signed-off-by: Sainath Grandhi <sainath.grandhi@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>

hypervisor/arch/x86/guest/vm_reset.c

@@ -0,0 +1,19 @@
+/*
+ * Copyright (C) 2019 Intel Corporation. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <vm.h>
+#include <vm_reset.h>
+#include <per_cpu.h>
+
+void shutdown_vm_from_idle(uint16_t pcpu_id)
+{
+	struct acrn_vm *vm = get_vm_from_vmid(per_cpu(shutdown_vm_id, pcpu_id));
+	const struct acrn_vcpu *vcpu = vcpu_from_vid(vm, BOOT_CPU_ID);
+
+	if (vcpu->pcpu_id == pcpu_id) {
+		(void)shutdown_vm(vm);
+	}
+}