diff --git a/sys/dev/hyperv/vmbus/vmbus_reg.h b/sys/dev/hyperv/vmbus/vmbus_reg.h
--- a/sys/dev/hyperv/vmbus/vmbus_reg.h
+++ b/sys/dev/hyperv/vmbus/vmbus_reg.h
@@ -102,7 +102,7 @@
 
 	struct hyperv_mon_param
 			mnf_param[VMBUS_MONTRIGS_MAX][VMBUS_MONTRIG_LEN];
-	uint8_t		mnf_rsvd4[1984];
+	uint8_t		mnf_rsvd4[PAGE_SIZE - 2112];
 } __packed;
 CTASSERT(sizeof(struct vmbus_mnf) == PAGE_SIZE);
 
@@ -168,7 +168,7 @@
 	} br_feature_bits;
 
 	/* Padding to PAGE_SIZE */
-	uint8_t			br_rsvd2[4020];
+	uint8_t			br_rsvd2[PAGE_SIZE - 76];
 
 	/*
 	 * Total guest to host interrupt count