Re: [PATCH v1 6/9] hw/net/xilinx_axienet: Handle fragmented packets from DMA

["Edgar E. Iglesias" <edgar.iglesias@xilinx.com>]

On Thu, Apr 30, 2020 at 06:24:36PM +0200, Edgar E. Iglesias wrote:
> From: "Edgar E. Iglesias" <edgar.iglesias@xilinx.com>
> 
> Add support for fragmented packets from the DMA.


In v2 I'll add a check in the tx-path for packets larger than c_txmem...

Cheers,
Edgar


> 
> Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
> ---
>  hw/net/xilinx_axienet.c | 31 ++++++++++++++++++++++++-------
>  1 file changed, 24 insertions(+), 7 deletions(-)
> 
> diff --git a/hw/net/xilinx_axienet.c b/hw/net/xilinx_axienet.c
> index bd48305577..e3826cf3fc 100644
> --- a/hw/net/xilinx_axienet.c
> +++ b/hw/net/xilinx_axienet.c
> @@ -402,6 +402,9 @@ struct XilinxAXIEnet {
>  
>      uint32_t hdr[CONTROL_PAYLOAD_WORDS];
>  
> +    uint8_t *txmem;
> +    uint32_t txpos;
> +
>      uint8_t *rxmem;
>      uint32_t rxsize;
>      uint32_t rxpos;
> @@ -421,6 +424,7 @@ static void axienet_rx_reset(XilinxAXIEnet *s)
>  static void axienet_tx_reset(XilinxAXIEnet *s)
>  {
>      s->tc = TC_JUM | TC_TX | TC_VLAN;
> +    s->txpos = 0;
>  }
>  
>  static inline int axienet_rx_resetting(XilinxAXIEnet *s)
> @@ -902,17 +906,28 @@ xilinx_axienet_data_stream_push(StreamSlave *obj, uint8_t *buf, size_t size,
>      XilinxAXIEnetStreamSlave *ds = XILINX_AXI_ENET_DATA_STREAM(obj);
>      XilinxAXIEnet *s = ds->enet;
>  
> -    /* We don't support fragmented packets yet.  */
> -    assert(eop);
> -
>      /* TX enable ?  */
>      if (!(s->tc & TC_TX)) {
>          return size;
>      }
>  
> +    if (s->txpos == 0 && eop) {
> +        /* Fast path single fragment.  */
> +        s->txpos = size;
> +    } else {
> +        memcpy(s->txmem + s->txpos, buf, size);
> +        buf = s->txmem;
> +        s->txpos += size;
> +
> +        if (!eop) {
> +            return size;
> +        }
> +    }
> +
>      /* Jumbo or vlan sizes ?  */
>      if (!(s->tc & TC_JUM)) {
> -        if (size > 1518 && size <= 1522 && !(s->tc & TC_VLAN)) {
> +        if (s->txpos > 1518 && s->txpos <= 1522 && !(s->tc & TC_VLAN)) {
> +            s->txpos = 0;
>              return size;
>          }
>      }
> @@ -923,7 +938,7 @@ xilinx_axienet_data_stream_push(StreamSlave *obj, uint8_t *buf, size_t size,
>          uint32_t tmp_csum;
>          uint16_t csum;
>  
> -        tmp_csum = net_checksum_add(size - start_off,
> +        tmp_csum = net_checksum_add(s->txpos - start_off,
>                                      buf + start_off);
>          /* Accumulate the seed.  */
>          tmp_csum += s->hdr[2] & 0xffff;
> @@ -936,12 +951,13 @@ xilinx_axienet_data_stream_push(StreamSlave *obj, uint8_t *buf, size_t size,
>          buf[write_off + 1] = csum & 0xff;
>      }
>  
> -    qemu_send_packet(qemu_get_queue(s->nic), buf, size);
> +    qemu_send_packet(qemu_get_queue(s->nic), buf, s->txpos);
>  
> -    s->stats.tx_bytes += size;
> +    s->stats.tx_bytes += s->txpos;
>      s->regs[R_IS] |= IS_TX_COMPLETE;
>      enet_update_irq(s);
>  
> +    s->txpos = 0;
>      return size;
>  }
>  
> @@ -989,6 +1005,7 @@ static void xilinx_enet_realize(DeviceState *dev, Error **errp)
>      s->TEMAC.parent = s;
>  
>      s->rxmem = g_malloc(s->c_rxmem);
> +    s->txmem = g_malloc(s->c_txmem);
>      return;
>  
>  xilinx_enet_realize_fail:
> -- 
> 2.20.1
>