Index: sys/dev/hyperv/vmbus/hv_vmbus_drv_freebsd.c
===================================================================
--- sys/dev/hyperv/vmbus/hv_vmbus_drv_freebsd.c
+++ sys/dev/hyperv/vmbus/hv_vmbus_drv_freebsd.c
@@ -118,7 +118,7 @@
 			 * This will cause message queue rescan to possibly
 			 * deliver another msg from the hypervisor
 			 */
-			wrmsr(HV_X64_MSR_EOM, 0);
+			wrmsr(MSR_HV_EOM, 0);
 		}
 	}
 }
@@ -170,7 +170,7 @@
 			 * This will cause message queue rescan to possibly
 			 * deliver another msg from the hypervisor
 			 */
-			wrmsr(HV_X64_MSR_EOM, 0);
+			wrmsr(MSR_HV_EOM, 0);
 		}
 	}
 
Index: sys/dev/hyperv/vmbus/hyperv_reg.h
===================================================================
--- sys/dev/hyperv/vmbus/hyperv_reg.h
+++ sys/dev/hyperv/vmbus/hyperv_reg.h
@@ -70,6 +70,8 @@
 #define MSR_HV_SIMP_RSVD_MASK		0x0ffeULL
 #define MSR_HV_SIMP_PGSHIFT		12
 
+#define MSR_HV_EOM			0x40000084
+
 #define MSR_HV_SINT0			0x40000090
 #define MSR_HV_SINT_VECTOR_MASK		0x00ffULL
 #define MSR_HV_SINT_RSVD1_MASK		0xff00ULL