apic: Move hypervisor detection of x2apic to hypervisor.h

Then we can reuse it for Xen later.
Acked-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: NAvi Kivity <avi@redhat.com>
Acked-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NSheng Yang <sheng@linux.intel.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

arch/x86/include/asm/hypervisor.h

@@ -20,6 +20,8 @@
 #ifndef _ASM_X86_HYPERVISOR_H
 #define _ASM_X86_HYPERVISOR_H
 
+#include <asm/kvm_para.h>
+
 extern void init_hypervisor(struct cpuinfo_x86 *c);
 extern void init_hypervisor_platform(void);
 
@@ -47,4 +49,11 @@ extern const struct hypervisor_x86 x86_hyper_vmware;
 extern const struct hypervisor_x86 x86_hyper_ms_hyperv;
 extern const struct hypervisor_x86 x86_hyper_xen_hvm;
 
+static inline bool hypervisor_x2apic_available(void)
+{
+	if (kvm_para_available())
+		return true;
+	return false;
+}
+
 #endif

arch/x86/kernel/apic/apic.c

@@ -50,8 +50,8 @@
 #include <asm/mtrr.h>
 #include <asm/smp.h>
 #include <asm/mce.h>
-#include <asm/kvm_para.h>
 #include <asm/tsc.h>
+#include <asm/hypervisor.h>
 
 unsigned int num_processors;
 
@@ -1476,7 +1476,8 @@ void __init enable_IR_x2apic(void)
 		/* IR is required if there is APIC ID > 255 even when running
 		 * under KVM
 		 */
-		if (max_physical_apicid > 255 || !kvm_para_available())
+		if (max_physical_apicid > 255 ||
+		    !hypervisor_x2apic_available())
 			goto nox2apic;
 		/*
 		 * without IR all CPUs can be addressed by IOAPIC/MSI