static void __init xen_hvm_init_mem_mapping(void)
{
	early_memunmap(HYPERVISOR_shared_info, PAGE_SIZE);
	HYPERVISOR_shared_info = __va(PFN_PHYS(shared_info_pfn));

	/*
	 * The virtual address of the shared_info page has changed, so
	 * the vcpu_info pointer for VCPU 0 is now stale.
	 *
	 * The prepare_boot_cpu callback will re-initialize it via
	 * xen_vcpu_setup, but we can't rely on that to be called for
	 * old Xen versions (xen_have_vector_callback == 0).
	 *
	 * It is, in any case, bad to have a stale vcpu_info pointer
	 * so reset it now.
	 */
	xen_vcpu_info_reset(0);
}
static void __init xen_hvm_init_mem_mapping(void)
{
	early_memunmap(HYPERVISOR_shared_info, PAGE_SIZE);
	HYPERVISOR_shared_info = __va(PFN_PHYS(shared_info_pfn));

	 
	xen_vcpu_info_reset(0);
}