Changeset 88424 in vbox for trunk/src/VBox/Devices

Timestamp:

Apr 8, 2021 6:20:16 PM (4 years ago)

Author:

vboxsync

Message:

Dev/E1000: (bugref:9850) Added a comment about relaxed RDT checks.

File:

• trunk/src/VBox/Devices/Network/DevE1000.cpp (modified) (1 diff)

trunk/src/VBox/Devices/Network/DevE1000.cpp

@@ -1731 +1731 @@
     pContext->rdt   = RDT;
     uint32_t cRxRingSize = pContext->rdlen / sizeof(E1KRXDESC);
+    /*
+     * Note that the checks for RDT are a bit different. Some guests, OS/2 for
+     * example, intend to use all descriptors in RX ring, so they point RDT
+     * right beyond the last descriptor in the ring. While this is not
+     * acceptable for other registers, it works out fine for RDT.
+     */
 #ifdef DEBUG
     if (pContext->rdh >= cRxRingSize)