hv: initial host reset implementation

- add the GUEST_FLAG_HIGHEST_SEVERITY flag to indicate that the guest has
  privilege to reboot the host system.

- this flag is statically assigned to guest(s) in vm_configurations.c in
  different scenarios.

- implement reset_host() function to reset the host. First try the ACPI
  reset register if available, then try the 0xcf9 PIO.

Tracked-On: #3145
Signed-off-by: Sainath Grandhi <sainath.grandhi@intel.com>
Signed-off-by: Zide Chen <zide.chen@intel.com>
Acked-by: Anthony Xu <anthony.xu@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>

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

@@ -218,6 +218,7 @@ void vrtc_init(struct acrn_vm *vm);
 
 bool is_lapic_pt_configured(const struct acrn_vm *vm);
 bool is_rt_vm(const struct acrn_vm *vm);
+bool is_highest_severity_vm(const struct acrn_vm *vm);
 bool vm_hide_mtrr(const struct acrn_vm *vm);
 
 #endif /* !ASSEMBLER */

hypervisor/include/public/acrn_common.h

@@ -53,6 +53,7 @@
 #define GUEST_FLAG_CLOS_REQUIRED		(1UL << 3U)     /* Whether CLOS is required */
 #define GUEST_FLAG_HIDE_MTRR			(1UL << 4U)  	/* Whether hide MTRR from VM */
 #define GUEST_FLAG_RT				(1UL << 5U)     /* Whether the vm is RT-VM */
+#define GUEST_FLAG_HIGHEST_SEVERITY		(1UL << 6U)     /* Whether has the highest severity */
 
 /* TODO: We may need to get this addr from guest ACPI instead of hardcode here */
 #define VIRTUAL_PM1A_CNT_ADDR		0x404U