[Qemu-devel] [PATCH] PCnet: Allow more then two TMDs

[Jan Kiszka <jan.kiszka@siemens.com>]

A simple fix to let the PCnet emulation handle more than two fragments
for outgoing packets.

There is still a hard-coded limitation of three fragments for incoming
packets, but that didn't hurt so far, even with our test cases (the RX
code is a bit too hairy to remove that limitation without risking
regressions :->).

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>

---
 hw/pcnet.c |   13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

Index: b/hw/pcnet.c
===================================================================
--- a/hw/pcnet.c
+++ b/hw/pcnet.c
@@ -1249,15 +1249,14 @@ static void pcnet_transmit(PCNetState *s
 #endif
         if (GET_FIELD(tmd.status, TMDS, STP)) {
             s->xmit_pos = 0;
-            if (!GET_FIELD(tmd.status, TMDS, ENP)) {
-                int bcnt = 4096 - GET_FIELD(tmd.length, TMDL, BCNT);
-                s->phys_mem_read(s->dma_opaque, PHYSADDR(s, tmd.tbadr),
-                                 s->buffer, bcnt, CSR_BSWP(s));
-                s->xmit_pos += bcnt;
-            }
             xmit_cxda = PHYSADDR(s,CSR_CXDA(s));
         }
-        if (GET_FIELD(tmd.status, TMDS, ENP) && (s->xmit_pos >= 0)) {
+        if (!GET_FIELD(tmd.status, TMDS, ENP)) {
+            int bcnt = 4096 - GET_FIELD(tmd.length, TMDL, BCNT);
+            s->phys_mem_read(s->dma_opaque, PHYSADDR(s, tmd.tbadr),
+                             s->buffer + s->xmit_pos, bcnt, CSR_BSWP(s));
+            s->xmit_pos += bcnt;
+        } else if (s->xmit_pos >= 0) {
             int bcnt = 4096 - GET_FIELD(tmd.length, TMDL, BCNT);
             s->phys_mem_read(s->dma_opaque, PHYSADDR(s, tmd.tbadr),
                              s->buffer + s->xmit_pos, bcnt, CSR_BSWP(s));