Index: /trunk/src/VBox/Devices/Network/DevE1000.cpp
===================================================================
--- /trunk/src/VBox/Devices/Network/DevE1000.cpp	(revision 43326)
+++ /trunk/src/VBox/Devices/Network/DevE1000.cpp	(revision 43327)
@@ -1127,4 +1127,6 @@
     /** TX: Will this frame be sent as GSO. */
     bool        fGSO;
+    /** TX: False will force segmentation in e1000 instead of sending frames as GSO. */
+    bool        fGSOEnabled;
     /** TX: Number of bytes in next packet. */
     uint32_t    cbTxAlloc;
@@ -3342,9 +3344,10 @@
  * Checks if we can use GSO processing for the current TSE frame.
  *
+ * @param   pState              The device state structure.
  * @param   pGso                The GSO context.
  * @param   pData               The first data descriptor of the frame.
  * @param   pCtx                The TSO context descriptor.
  */
-DECLINLINE(bool) e1kCanDoGso(PCPDMNETWORKGSO pGso, E1KTXDAT const *pData, E1KTXCTX const *pCtx)
+DECLINLINE(bool) e1kCanDoGso(E1KSTATE *pState, PCPDMNETWORKGSO pGso, E1KTXDAT const *pData, E1KTXCTX const *pCtx)
 {
     if (!pData->cmd.fTSE)
@@ -3356,4 +3359,9 @@
     {
         E1kLog(("e1kCanDoGso: VLE\n"));
+        return false;
+    }
+    if (RT_UNLIKELY(!pState->fGSOEnabled))
+    {
+        E1kLog3(("e1kCanDoGso: GSO disabled via CFGM\n"));
         return false;
     }
@@ -4432,5 +4440,5 @@
                     cbVTag = 4;
                 E1kLog3(("%s About to allocate TX buffer: cbVTag=%u\n", INSTANCE(pState), cbVTag));
-                if (e1kCanDoGso(&pState->GsoCtx, &pDesc->data, &pState->contextTSE))
+                if (e1kCanDoGso(pState, &pState->GsoCtx, &pDesc->data, &pState->contextTSE))
                     rc = e1kXmitAllocBuf(pState, pState->contextTSE.dw2.u20PAYLEN + pState->contextTSE.dw3.u8HDRLEN + cbVTag,
                                     true /*fExactSize*/, true /*fGso*/);
@@ -4830,5 +4838,5 @@
                         pState->u16VTagTCI = pDesc->data.dw3.u16Special;
                     }
-                    pState->fGSO = e1kCanDoGso(&pState->GsoCtx, &pDesc->data, &pState->contextTSE);
+                    pState->fGSO = e1kCanDoGso(pState, &pState->GsoCtx, &pDesc->data, &pState->contextTSE);
                 }
                 cbPacket += pDesc->data.cmd.u20DTALEN;
@@ -7268,5 +7276,5 @@
     if (!CFGMR3AreValuesValid(pCfg, "MAC\0" "CableConnected\0" "AdapterType\0"
                                     "LineSpeed\0" "GCEnabled\0" "R0Enabled\0"
-                                    "EthernetCRC\0" "LinkUpDelay\0"))
+                                    "EthernetCRC\0" "GSOEnabled\0" "LinkUpDelay\0"))
         return PDMDEV_SET_ERROR(pDevIns, VERR_PDM_DEVINS_UNKNOWN_CFG_VALUES,
                                 N_("Invalid configuration for E1000 device"));
@@ -7277,4 +7285,5 @@
     pState->fGCEnabled   = true;
     pState->fEthernetCRC = true;
+    pState->fGSOEnabled  = true;
 
     /* Get config params */
@@ -7307,4 +7316,10 @@
         return PDMDEV_SET_ERROR(pDevIns, rc,
                                 N_("Configuration error: Failed to get the value of 'EthernetCRC'"));
+
+    rc = CFGMR3QueryBoolDef(pCfg, "GSOEnabled", &pState->fGSOEnabled, true);
+    if (RT_FAILURE(rc))
+        return PDMDEV_SET_ERROR(pDevIns, rc,
+                                N_("Configuration error: Failed to get the value of 'GSOEnabled'"));
+
     rc = CFGMR3QueryU32Def(pCfg, "LinkUpDelay", (uint32_t*)&pState->cMsLinkUpDelay, 5000); /* ms */
     if (RT_FAILURE(rc))
@@ -7322,7 +7337,8 @@
     }
 
-    E1kLog(("%s Chip=%s LinkUpDelay=%ums EthernetCRC=%s\n", INSTANCE(pState),
+    E1kLog(("%s Chip=%s LinkUpDelay=%ums EthernetCRC=%s GSO=%s\n", INSTANCE(pState),
             g_Chips[pState->eChip].pcszName, pState->cMsLinkUpDelay,
-            pState->fEthernetCRC ? "on" : "off"));
+            pState->fEthernetCRC ? "on" : "off",
+            pState->fGSOEnabled ? "enabled" : "disabled"));
 
     /* Initialize state structure */