Re: [PATCH] Revert "hw/net: Fix the transmission return size"

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

On Thu, Nov 06, 2025 at 12:48:37PM +0300, Ilya Repko wrote:
> This reverts commit 3a6d374b754b4b345195ff6846eeaffedc96a7c5.
> 
> During axienet_eth_rx_notify(), s->rxpos is modified to indicate how much
> data was pushed to AXI DMA. eth_rx() would then return this value.
> If at 0, network subsystem would consider packet reception as failed
> and put the packet in a queue for later.
> 
> Before we attempt to push packet data to AXI DMA, the packet is stored
> in s->rxmem buffer. If an attempt to push data fails, we will reattempt
> to deliver it from s->rxmem buffer once s2mm stream gets a new descriptor.
> s->rxmem would not be overwritten by a subsequent eth_rx() call, because
> eth_can_rx() protects it in case it has any data at all. Leaving the packet
> in a NetQueue though effectively duplicates it.
> 
> Therefore, eth_rx() must indicate successful packet reception in case
> data push to AXI DMA fails.

Hi,

Adding Fea since we're reverting his patch, he may have some insights.

What you describe sounds reasonable but I think we've seen issues with
both your version (the original one) and Fea's version.

What machine are you running? Are you running Linux guests?

Cheers,
Edgar




> 
> Signed-off-by: Ilya Repko <i.repko@syntacore.com>
> ---
>  hw/net/xilinx_axienet.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/hw/net/xilinx_axienet.c b/hw/net/xilinx_axienet.c
> index 31e7708082..101b3f260a 100644
> --- a/hw/net/xilinx_axienet.c
> +++ b/hw/net/xilinx_axienet.c
> @@ -867,7 +867,7 @@ static ssize_t eth_rx(NetClientState *nc, const uint8_t *buf, size_t size)
>      axienet_eth_rx_notify(s);
>  
>      enet_update_irq(s);
> -    return s->rxpos;
> +    return size;
>  }
>  
>  static size_t
> -- 
> 2.51.1
>