diff --git a/hw/net/xilinx_ethlite.c b/hw/net/xilinx_ethlite.c
index 330dccb83d..d54f96df24 100644
--- a/hw/net/xilinx_ethlite.c
+++ b/hw/net/xilinx_ethlite.c
@@ -3,6 +3,9 @@
  *
  * Copyright (c) 2009 Edgar E. Iglesias.
  *
+ * DS580: https://docs.amd.com/v/u/en-US/xps_ethernetlite
+ * LogiCORE IP XPS Ethernet Lite Media Access Controller
+ *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
@@ -33,6 +36,7 @@
 #include "trace.h"
 
 #define R_TX_BUF0     0
+#define BUFSZ_MAX      0x07e4
 #define R_TX_LEN0     (0x07f4 / 4)
 #define R_TX_GIE0     (0x07f8 / 4)
 #define R_TX_CTRL0    (0x07fc / 4)
@@ -191,7 +195,7 @@ static ssize_t eth_rx(NetClientState *nc, const uint8_t *buf, size_t size)
         return -1;
     }
 
-    if (size > (R_MAX - R_RX_BUF0 - rxbase) * 4) {
+    if (size >= BUFSZ_MAX) {
         trace_ethlite_pkt_size_too_big(size);
         return -1;
     }