diff --git a/hw/net/e1000.c b/hw/net/e1000.c
index d8da2f6528..15949a3d64 100644
--- a/hw/net/e1000.c
+++ b/hw/net/e1000.c
@@ -667,9 +667,11 @@ process_tx_desc(E1000State *s, struct e1000_tx_desc *dp)
addr = le64_to_cpu(dp->buffer_addr);
if (tp->cptse) {
+ assert(tp->tso_props.hdr_len);
msh = tp->tso_props.hdr_len + tp->tso_props.mss;
do {
bytes = split_size;
+ assert(msh > tp->size);
if (tp->size + bytes > msh)
bytes = msh - tp->size;
@@ -681,22 +683,26 @@ process_tx_desc(E1000State *s, struct e1000_tx_desc *dp)
memmove(tp->header, tp->data, tp->tso_props.hdr_len);
}
tp->size = sz;
+ assert(tp->size); /* sz may get truncated */
addr += bytes;
if (sz == msh) {
xmit_seg(s);
memmove(tp->data, tp->header, tp->tso_props.hdr_len);
tp->size = tp->tso_props.hdr_len;
}
+ assert(split_size >= bytes);
split_size -= bytes;
} while (bytes && split_size);
} else {
split_size = MIN(sizeof(tp->data) - tp->size, split_size);
+ assert(tp->size && split_size);
pci_dma_read(d, addr, tp->data + tp->size, split_size);
tp->size += split_size;
}
if (!(txd_lower & E1000_TXD_CMD_EOP))
return;
+ assert(tp->size && tp->tso_props.hdr_len);
if (!(tp->cptse && tp->size < tp->tso_props.hdr_len)) {
xmit_seg(s);
}