[Qemu-devel] [PULL 25/37] net/cadence_gem: Fix rx multi-fragment packets

[Peter Maydell <peter.maydell@linaro.org>]

From: Peter Crosthwaite <peter.crosthwaite@xilinx.com>

Bytes_to_copy was being updated before its final use where it
advances the rx buffer pointer. This was causing total mayhem,
where packet data for any subsequent fragments was being fetched
from the wrong place.

Reported-by: Deepika Dhamija <deepika@xilinx.com>
Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: c2a1c65c1fd06eb274442a0fa4a6839d940e145e.1386136219.git.peter.crosthwaite@xilinx.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 hw/net/cadence_gem.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/net/cadence_gem.c b/hw/net/cadence_gem.c
index 8cfad04..2afafdf 100644
--- a/hw/net/cadence_gem.c
+++ b/hw/net/cadence_gem.c
@@ -733,8 +733,8 @@ static ssize_t gem_receive(NetClientState *nc, const uint8_t *buf, size_t size)
         /* Copy packet data to emulated DMA buffer */
         cpu_physical_memory_write(rx_desc_get_buffer(s->rx_desc) + rxbuf_offset,
                                   rxbuf_ptr, MIN(bytes_to_copy, rxbufsize));
-        bytes_to_copy -= MIN(bytes_to_copy, rxbufsize);
         rxbuf_ptr += MIN(bytes_to_copy, rxbufsize);
+        bytes_to_copy -= MIN(bytes_to_copy, rxbufsize);
 
         /* Update the descriptor.  */
         if (first_desc) {
-- 
1.8.5