diff --git a/hw/e1000.c b/hw/e1000.c index 70aba11296..8d87492e0b 100644 --- a/hw/e1000.c +++ b/hw/e1000.c @@ -344,6 +344,15 @@ is_vlan_txd(uint32_t txd_lower) return ((txd_lower & E1000_TXD_CMD_VLE) != 0); } +/* FCS aka Ethernet CRC-32. We don't get it from backends and can't + * fill it in, just pad descriptor length by 4 bytes unless guest + * told us to trip it off the packet. */ +static inline int +fcs_len(E1000State *s) +{ + return (s->mac_reg[RCTL] & E1000_RCTL_SECRC) ? 0 : 4; +} + static void xmit_seg(E1000State *s) { @@ -662,7 +671,7 @@ e1000_receive(VLANClientState *nc, const uint8_t *buf, size_t size) if (desc.buffer_addr) { cpu_physical_memory_write(le64_to_cpu(desc.buffer_addr), (void *)(buf + vlan_offset), size); - desc.length = cpu_to_le16(size + 4 /* for FCS */); + desc.length = cpu_to_le16(size + fcs_len(s)); desc.status |= E1000_RXD_STAT_EOP|E1000_RXD_STAT_IXSM; } else // as per intel docs; skip descriptors with null buf addr DBGOUT(RX, "Null RX descriptor!!\n");