hv: add vm restart API

And export the API to DM. DM will do system reboot/S3 resume based
on this API.

Also add the pre-assumption description for some vm APIs.

Signed-off-by: Yin Fengwei <fengwei.yin@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>

hypervisor/arch/x86/guest/vm.c

@@ -289,6 +289,9 @@ int shutdown_vm(struct vm *vm)
 	return status;
 }
 
+/**
+ *  * @pre vm != NULL
+ */
 int start_vm(struct vm *vm)
 {
 	struct vcpu *vcpu = NULL;
@@ -303,9 +306,33 @@ int start_vm(struct vm *vm)
 	return 0;
 }
 
-/*
- * DM only pause vm for shutdown/reboot. If we need to
- * extend the pause vm for DM, this API should be extended.
+/**
+ *  * @pre vm != NULL
+ */
+int reset_vm(struct vm *vm)
+{
+	int i;
+	struct vcpu *vcpu = NULL;
+
+	if (vm->state != VM_PAUSED)
+		return -1;
+
+	foreach_vcpu(i, vm, vcpu) {
+		reset_vcpu(vcpu);
+		if (is_vcpu_bsp(vcpu))
+			vm_sw_loader(vm, vcpu);
+
+		vcpu->arch_vcpu.cpu_mode = CPU_MODE_REAL;
+	}
+
+	vioapic_reset(vm->arch_vm.virt_ioapic);
+
+	start_vm(vm);
+	return 0;
+}
+
+/**
+ *  * @pre vm != NULL
  */
 void pause_vm(struct vm *vm)
 {
@@ -323,6 +350,9 @@ void pause_vm(struct vm *vm)
 	}
 }
 
+/**
+ *  * @pre vm != NULL
+ */
 void resume_vm(struct vm *vm)
 {
 	uint16_t i;
@@ -335,13 +365,19 @@ void resume_vm(struct vm *vm)
 	vm->state = VM_STARTED;
 }
 
-/* Resume vm from S3 state
+/**
+ * @brief Resume vm from S3 state
  *
  * To resume vm after guest enter S3 state:
  * - reset BSP
  * - BSP will be put to real mode with entry set as wakeup_vec
  * - init_vmcs BSP. We could call init_vmcs here because we know current
  *   pcpu is mapped to BSP of vm.
+ *
+ * @vm[in]		vm pointer to vm data structure
+ * @wakeup_vec[in]	The resume address of vm
+ *
+ * @pre vm != NULL
  */
 void resume_vm_from_s3(struct vm *vm, uint32_t wakeup_vec)
 {

hypervisor/arch/x86/guest/vmcall.c

@@ -65,6 +65,11 @@ int vmcall_vmexit_handler(struct vcpu *vcpu)
 		ret = hcall_start_vm((uint16_t)param1);
 		break;
 
+	case HC_RESET_VM:
+		/* param1: vmid */
+		ret = hcall_reset_vm((uint16_t)param1);
+		break;
+
 	case HC_PAUSE_VM:
 		/* param1: vmid */
 		ret = hcall_pause_vm((uint16_t)param1);

hypervisor/common/hypercall.c

@@ -266,6 +266,17 @@ int32_t hcall_create_vcpu(struct vm *vm, uint16_t vmid, uint64_t param)
 	return ret;
 }
 
+int32_t hcall_reset_vm(uint16_t vmid)
+{
+	struct vm *target_vm = get_vm_from_vmid(vmid);
+
+	if ((target_vm == NULL) || is_vm0(target_vm))
+		return -1;
+
+	reset_vm(target_vm);
+	return 0;
+}
+
 int32_t hcall_assert_irqline(struct vm *vm, uint16_t vmid, uint64_t param)
 {
 	int32_t ret = 0;

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

@@ -173,6 +173,7 @@ void pause_vm(struct vm *vm);
 void resume_vm(struct vm *vm);
 void resume_vm_from_s3(struct vm *vm, uint32_t wakeup_vec);
 int start_vm(struct vm *vm);
+int reset_vm(struct vm *vm);
 int create_vm(struct vm_description *vm_desc, struct vm **vm);
 int prepare_vm0(void);
 #ifdef CONFIG_VM0_DESC

hypervisor/include/common/hypercall.h

@@ -76,6 +76,20 @@ int32_t hcall_create_vm(struct vm *vm, uint64_t param);
  */
 int32_t hcall_destroy_vm(uint16_t vmid);
 
+/**
+ * @brief reset virtual machine
+ *
+ * Reset a virtual machine, it will make target VM rerun from
+ * pre-defined entry. Comparing to start vm, this function reset
+ * each vcpu state and do some initialization for guest.
+ * The function will return -1 if the target VM does not exist.
+ *
+ * @param vmid ID of the VM
+ *
+ * @return 0 on success, non-zero on error.
+ */
+int32_t hcall_reset_vm(uint16_t vmid);
+
 /**
  * @brief start virtual machine
  *

hypervisor/include/public/acrn_hv_defs.h

@@ -35,6 +35,7 @@
 #define HC_START_VM                 BASE_HC_ID(HC_ID, HC_ID_VM_BASE + 0x02UL)
 #define HC_PAUSE_VM                 BASE_HC_ID(HC_ID, HC_ID_VM_BASE + 0x03UL)
 #define HC_CREATE_VCPU              BASE_HC_ID(HC_ID, HC_ID_VM_BASE + 0x04UL)
+#define HC_RESET_VM                 BASE_HC_ID(HC_ID, HC_ID_VM_BASE + 0x05UL)
 
 /* IRQ and Interrupts */
 #define HC_ID_IRQ_BASE              0x20UL