Changeset 76766 in vbox for trunk/src/VBox

Timestamp:

Jan 11, 2019 8:56:40 AM (6 years ago)

Author:

vboxsync

Message:

PCnet: Improved loopback mode emulation.

File:

• trunk/src/VBox/Devices/Network/DevPCNet.cpp (modified) (6 diffs)

trunk/src/VBox/Devices/Network/DevPCNet.cpp

@@ -293 +293 @@
  * There were also non-busmastering LANCE adapters, such as the BICC 4110-1, DEC DEPCA,
  * or NTI 16. Those are uninteresting.
- * 
+ *
  * Newer adapters based on the integrated PCnet-ISA (Am79C960) and later have a fixed
  * register layout compatible with the NE2100. However, they may still require different
@@ -1874 +1874 @@
  * Write data into guest receive buffers.
  */
-static void pcnetReceiveNoSync(PPCNETSTATE pThis, const uint8_t *buf, size_t cbToRecv, bool fAddFCS)
+static void pcnetReceiveNoSync(PPCNETSTATE pThis, const uint8_t *buf, size_t cbToRecv, bool fAddFCS, bool fLoopback)
 {
     PPDMDEVINS pDevIns = PCNETSTATE_2_DEVINS(pThis);
@@ -1959 +1959 @@
 
             if (!fStrip) {
-                while (cbToRecv < 60)
-                    src[cbToRecv++] = 0;
+                /* In loopback mode, Runt Packed Accept is always enabled internally;
+                 * don't do any padding because guest may be looping back very short packets.
+                 */
+                if (!fLoopback)
+                    while (cbToRecv < 60)
+                        src[cbToRecv++] = 0;
 
                 if (fAddFCS)
@@ -2109 +2113 @@
     /* see description of TXDPOLL:
      * ``transmit polling will take place following receive activities'' */
-    pcnetPollRxTx(pThis);
+    if (!fLoopback)
+        pcnetPollRxTx(pThis);
     pcnetUpdateIrq(pThis);
 }
@@ -2234 +2239 @@
             pcnetRdtePoll(pThis);
 
-        pcnetReceiveNoSync(pThis, pThis->abLoopBuf, pSgBuf->cbUsed, true /* fAddFCS */);
+        pcnetReceiveNoSync(pThis, pThis->abLoopBuf, pSgBuf->cbUsed, true /* fAddFCS */, fLoopback);
         pThis->Led.Actual.s.fReading = 0;
         rc = VINF_SUCCESS;
@@ -4676 +4681 @@
         if (cb > 70) /* unqualified guess */
             pThis->Led.Asserted.s.fReading = pThis->Led.Actual.s.fReading = 1;
-        pcnetReceiveNoSync(pThis, (const uint8_t *)pvBuf, cb, fAddFCS);
+        pcnetReceiveNoSync(pThis, (const uint8_t *)pvBuf, cb, fAddFCS, false);
         pThis->Led.Actual.s.fReading = 0;
     }