Re: [Qemu-arm] [Qemu-devel] [PATCH v2 2/4] ftgmac100: add IEEE 802.1Q VLAN support

[Peter Maydell]

On 30 May 2018 at 07:17, Cédric Le Goater <address@hidden> wrote:
> The ftgmac100 NIC supports VLAN tag insertion and the MAC engine also
> has a control to remove VLAN tags from received packets.
>
> The VLAN control bits and VLAN tag information are contained in the
> second word of the transmit and receive descriptors. The Insert VLAN
> bit and the VLAN Tag available bit are only valid in the first segment
> of the packet.
>
> Signed-off-by: Cédric Le Goater <address@hidden>
> Reviewed-by: Philippe Mathieu-Daudé <address@hidden>

> +        /* Check for VLAN */
> +        if (bd.des0 & FTGMAC100_TXDES0_FTS &&
> +            bd.des1 & FTGMAC100_TXDES1_INS_VLANTAG &&
> +            be16_to_cpu(PKT_GET_ETH_HDR(ptr)->h_proto) != ETH_P_VLAN) {

This is kind of bogus because there's no guarantee that h_proto here
is sufficiently aligned to do a halfword load. However this is
a problem common to all the PKT_GET_* macros so we should probably
attack it separately to this series.

Getting the ethernet h_proto field seems common enough that
something like

static inline uint16_t eth_get_proto(uint8_t *pkt)
{
    return lduw_be_p(&PKT_GET_ETH_HDR(pkt)->h_proto);
}

would be handy in eth.h.


Anyway, I've applied this series to target-arm.next.

thanks
-- PMM