xen: implement apic ipi interface

Map native ipi vector to xen vector.
Implement apic ipi interface with xen_send_IPI_one.

Tested-by: Steven Noonan <steven@uplinklabs.net>
Signed-off-by: Ben Guthro <ben@guthro.net>
Signed-off-by: Lin Ming <mlin@ss.pku.edu.cn>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 4f51beb..1ed61c2 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -74,6 +74,7 @@
 
 #include "xen-ops.h"
 #include "mmu.h"
+#include "smp.h"
 #include "multicalls.h"
 
 EXPORT_SYMBOL_GPL(hypercall_page);
@@ -849,6 +850,14 @@
 	apic->icr_write = xen_apic_icr_write;
 	apic->wait_icr_idle = xen_apic_wait_icr_idle;
 	apic->safe_wait_icr_idle = xen_safe_apic_wait_icr_idle;
+
+#ifdef CONFIG_SMP
+	apic->send_IPI_allbutself = xen_send_IPI_allbutself;
+	apic->send_IPI_mask_allbutself = xen_send_IPI_mask_allbutself;
+	apic->send_IPI_mask = xen_send_IPI_mask;
+	apic->send_IPI_all = xen_send_IPI_all;
+	apic->send_IPI_self = xen_send_IPI_self;
+#endif
 }
 
 #endif