diff --git a/include/asm-x86/irq_vectors.h b/include/asm-x86/irq_vectors.h
index 90b1d1f12f08d652d39fef01e241ed321f38c415..b95d167b7fb26d8697a1d1a56b2000648b042e8b 100644
--- a/include/asm-x86/irq_vectors.h
+++ b/include/asm-x86/irq_vectors.h
@@ -109,7 +109,15 @@
 #define LAST_VM86_IRQ		15
 #define invalid_vm86_irq(irq)	((irq) < 3 || (irq) > 15)
 
-#if !defined(CONFIG_X86_VOYAGER)
+#ifdef CONFIG_X86_64
+# if NR_CPUS < MAX_IO_APICS
+#  define NR_IRQS (NR_VECTORS + (32 * NR_CPUS))
+# else
+#  define NR_IRQS (NR_VECTORS + (32 * MAX_IO_APICS))
+# endif
+# define NR_IRQ_VECTORS NR_IRQS
+
+#elif !defined(CONFIG_X86_VOYAGER)
 
 # if defined(CONFIG_X86_IO_APIC) || defined(CONFIG_PARAVIRT) || defined(CONFIG_X86_VISWS)