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Date: Fri, 19 Jun 2015 11:16:35 +0200
From: Thomas Huth <thuth@redhat.com>
Message-ID: <20150619111635.1a37f6e2@thh440s>
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Subject: Re: [Qemu-devel] [PATCH 5/6] vhost-net: tell tap backend about the
 vnet endianness
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To: Greg Kurz <gkurz@linux.vnet.ibm.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>, Jason Wang <jasowang@redhat.com>, qemu-devel@nongnu.org, Stefan Hajnoczi <stefanha@redhat.com>, "Michael S. Tsirkin" <mst@redhat.com>


 Hi,

On Wed, 17 Jun 2015 15:23:49 +0200
Greg Kurz <gkurz@linux.vnet.ibm.com> wrote:

> The default behaviour for TAP/MACVTAP is to consider vnet as native endian.
> 
> This patch handles the cases when this is not true:
> - virtio 1.0: always little-endian
> - legacy cross-endian
> 
> Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
> ---
>  hw/net/vhost_net.c |   33 ++++++++++++++++++++++++++++++++-
>  1 file changed, 32 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
> index 1c55517e3611..8cbb2f618c1c 100644
> --- a/hw/net/vhost_net.c
> +++ b/hw/net/vhost_net.c
...
> @@ -365,6 +394,8 @@ void vhost_net_stop(VirtIODevice *dev, NetClientState *ncs,
>          fflush(stderr);
>      }
>      assert(r >= 0);
> +
> +    assert(vhost_net_set_vnet_endian(dev, ncs[0].peer, false) >= 0);
>  }

Putting the vhost_net_set_vnet_endian() within the assert statement
looks somewhat wrong to me. assert() gets defined to nothing in case
NDEBUG is defined, so the call would then simply be dropped.
I guess you rather want something like this here:

    r = vhost_net_set_vnet_endian(dev, ncs[0].peer, false);
    assert(r >= 0);

?

 Thomas