On Fri, Feb 20, 2015 at 11:15:05AM +0100, Greg Kurz wrote:
> Without this patch, packets are being silently dropped by the tap backend.
>
> Signed-off-by: Greg Kurz <gkurz@xxxxxxxxxxxxxxxxxx>
I think it's the wrong place to fix this. You want a tun/macvtap ioctl
to enable legacy big endian stuff. Treat it same way as vhost, with a
config option to enable.
> ---
> drivers/vhost/net.c | 32 ++++++++++++++++++++++++++------
> 1 file changed, 26 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
> index afa06d2..2923eee 100644
> --- a/drivers/vhost/net.c
> +++ b/drivers/vhost/net.c
> @@ -288,6 +288,16 @@ static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success)
> rcu_read_unlock_bh();
> }
>
> +static void fix_virtio_net_hdr(struct vhost_virtqueue *vq)
> +{
> + struct virtio_net_hdr *hdr = vq->iov[0].iov_base;
> +
> + hdr->hdr_len = vhost16_to_cpu(vq, hdr->hdr_len);
> + hdr->gso_size = vhost16_to_cpu(vq, hdr->gso_size);
> + hdr->csum_start = vhost16_to_cpu(vq, hdr->csum_start);
> + hdr->csum_offset = vhost16_to_cpu(vq, hdr->csum_offset);
> +}
> +
> /* Expects to be always run from workqueue - which acts as
> * read-size critical section for our kind of RCU. */
> static void handle_tx(struct vhost_net *net)
> @@ -352,6 +362,10 @@ static void handle_tx(struct vhost_net *net)
> "out %d, int %d\n", out, in);
> break;
> }
> +
> + if (!hdr_size)
> + fix_virtio_net_hdr(vq);
> +
> /* Skip header. TODO: support TSO. */
> len = iov_length(vq->iov, out);
> iov_iter_init(&msg.msg_iter, WRITE, vq->iov, out, len);
> @@ -609,12 +623,18 @@ static void handle_rx(struct vhost_net *net)
> continue;
> }
> /* Supply virtio_net_hdr if VHOST_NET_F_VIRTIO_NET_HDR */
> - if (unlikely(vhost_hlen) &&
> - copy_to_iter(&hdr, sizeof(hdr), &fixup) != sizeof(hdr)) {
> - vq_err(vq, "Unable to write vnet_hdr at addr %p\n",
> - vq->iov->iov_base);
> - break;
> - }
> + if (unlikely(vhost_hlen)) {
> + size_t len = copy_to_iter(&hdr, sizeof(hdr), &fixup);
> +
> + if (len != sizeof(hdr)) {
> + vq_err(vq,
> + "Unable to write vnet_hdr at addr %p\n",
> + vq->iov->iov_base);
> + break;
> + }
> + } else
> + fix_virtio_net_hdr(vq);
> +
> /* TODO: Should check and handle checksum. */
>
> num_buffers = cpu_to_vhost16(vq, headcount);
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