e1000: only use TSE if enabled for current packet (Anthony Xu).

Previously, all data descriptors used TSE context descriptor by default,
It's not correct, per spec, data descriptor uses TSE bit to indicate
whether use TSE,
Legacy data descripter never use TSE.
This patch fixed this bug.


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@4878 c046a42c-6fe2-441c-8c8c-71466251a162

hw/e1000.c

@@ -105,6 +105,7 @@ typedef struct E1000State_st {
         char tse;
         char ip;
         char tcp;
+        char cptse;     // current packet tse bit
     } tx;
 
     struct {
@@ -308,7 +309,7 @@ xmit_seg(E1000State *s)
     unsigned int frames = s->tx.tso_frames, css, sofar, n;
     struct e1000_tx *tp = &s->tx;
 
-    if (tp->tse) {
+    if (tp->tse && tp->cptse) {
         css = tp->ipcss;
         DBGOUT(TXSUM, "frames %d size %d ipcss %d\n",
                frames, tp->size, css);
@@ -382,37 +383,49 @@ process_tx_desc(E1000State *s, struct e1000_tx_desc *dp)
             tp->tucso = tp->tucss + (tp->tcp ? 16 : 6);
         }
         return;
-    } else if (dtype == (E1000_TXD_CMD_DEXT | E1000_TXD_DTYP_D))
+    } else if (dtype == (E1000_TXD_CMD_DEXT | E1000_TXD_DTYP_D)) {
+        // data descriptor
         tp->sum_needed = le32_to_cpu(dp->upper.data) >> 8;
+        tp->cptse = ( txd_lower & E1000_TXD_CMD_TSE ) ? 1 : 0;
+    } else
+        // legacy descriptor
+        tp->cptse = 0;
 
     addr = le64_to_cpu(dp->buffer_addr);
-    if (tp->tse) {
+    if (tp->tse && tp->cptse) {
         hdr = tp->hdr_len;
         msh = hdr + tp->mss;
+        do {
+            bytes = split_size;
+            if (tp->size + bytes > msh)
+                bytes = msh - tp->size;
+            cpu_physical_memory_read(addr, tp->data + tp->size, bytes);
+            if ((sz = tp->size + bytes) >= hdr && tp->size < hdr)
+                memmove(tp->header, tp->data, hdr);
+            tp->size = sz;
+            addr += bytes;
+            if (sz == msh) {
+                xmit_seg(s);
+                memmove(tp->data, tp->header, hdr);
+                tp->size = hdr;
+            }
+        } while (split_size -= bytes);
+    } else if (!tp->tse && tp->cptse) {
+        // context descriptor TSE is not set, while data descriptor TSE is set
+        DBGOUT(TXERR, "TCP segmentaion Error\n");
+    } else {
+        cpu_physical_memory_read(addr, tp->data + tp->size, split_size);
+        tp->size += split_size;
     }
-    do {
-        bytes = split_size;
-        if (tp->size + bytes > msh)
-            bytes = msh - tp->size;
-        cpu_physical_memory_read(addr, tp->data + tp->size, bytes);
-        if ((sz = tp->size + bytes) >= hdr && tp->size < hdr)
-            memmove(tp->header, tp->data, hdr);
-        tp->size = sz;
-        addr += bytes;
-        if (sz == msh) {
-            xmit_seg(s);
-            memmove(tp->data, tp->header, hdr);
-            tp->size = hdr;
-        }
-    } while (split_size -= bytes);
 
     if (!(txd_lower & E1000_TXD_CMD_EOP))
         return;
-    if (tp->size > hdr)
+    if (!(tp->tse && tp->cptse && tp->size < hdr))
         xmit_seg(s);
     tp->tso_frames = 0;
     tp->sum_needed = 0;
     tp->size = 0;
+    tp->cptse = 0;
 }
 
 static uint32_t