Re: [Qemu-devel] [PATCH v2] net: imx: limit buffer descriptor count

[Paolo Bonzini <pbonzini@redhat.com>]

On 22/09/2016 12:31, P J P wrote:
> From: Prasad J Pandit <pjp@fedoraproject.org>
> 
> i.MX Fast Ethernet Controller uses buffer descriptors to manage
> data flow to/fro receive & transmit queues. While transmitting
> packets, it could continue to read buffer descriptors if a buffer
> descriptor has length of zero and has crafted values in bd.flags.
> Set an upper limit to number of buffer descriptors.
> 
> Reported-by: Li Qiang <liqiang6-s@360.cn>
> Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
> ---
>  hw/net/imx_fec.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> Update per
>   -> https://lists.gnu.org/archive/html/qemu-devel/2016-09/msg05284.html
> 
> diff --git a/hw/net/imx_fec.c b/hw/net/imx_fec.c
> index e60e338..547fa99 100644
> --- a/hw/net/imx_fec.c
> +++ b/hw/net/imx_fec.c
> @@ -94,6 +94,8 @@ static const VMStateDescription vmstate_imx_fec = {
>  #define PHY_INT_PARFAULT            (1 << 2)
>  #define PHY_INT_AUTONEG_PAGE        (1 << 1)
>  
> +#define IMX_MAX_DESC                1024
> +
>  static void imx_fec_update(IMXFECState *s);
>  
>  /*
> @@ -264,12 +266,12 @@ static void imx_fec_update(IMXFECState *s)
>  
>  static void imx_fec_do_tx(IMXFECState *s)
>  {
> -    int frame_size = 0;
> +    int frame_size = 0, descnt = 0;
>      uint8_t frame[FEC_MAX_FRAME_SIZE];
>      uint8_t *ptr = frame;
>      uint32_t addr = s->tx_descriptor;
>  
> -    while (1) {
> +    while (descnt++ < IMX_MAX_DESC) {
>          IMXFECBufDesc bd;
>          int len;
>  
> 

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>