Re: [PATCH 0/3] vhost_net: support for cross endian guests

["Michael S. Tsirkin" <mst@redhat.com>]

On Fri, Feb 20, 2015 at 11:07:24AM +0100, Greg Kurz wrote:
> Hi,
> 
> This patchset allows vhost_net to be used with legacy virtio
> when guest and host have a different endianness. It is based
> on previous work by Cédric Le Goater:
> 
> https://www.mail-archive.com/kvm-ppc@vger.kernel.org/msg09848.html
> 
> As suggested by MST:
> - the API now asks for a specific format (big endian) instead of the hint
>   whether byteswap is needed or not (patch 1)
> - rebased on top of the virtio-1 accessors (patch 2)
> 
> Patch 3 is a separate fix: I think it is also valid for virtio-1.

I don't think so. See e.g. this code in tun:
                        gso.csum_offset = cpu_to_tun16(tun, skb->csum_offset);
looks like it has the correct endian-ness for virtio-1.



> Please comment.
> 
> ---
> 
> Greg Kurz (3):
>       vhost: add VHOST_VRING_F_LEGACY_BIG_ENDIAN flag
>       vhost: add support for legacy virtio
>       vhost_net: fix virtio_net header endianness
> 
> 
>  drivers/vhost/net.c        |   32 ++++++++++++++++++++++++++------
>  drivers/vhost/vhost.c      |    6 +++++-
>  drivers/vhost/vhost.h      |   23 +++++++++++++++++------
>  include/uapi/linux/vhost.h |    2 ++
>  4 files changed, 50 insertions(+), 13 deletions(-)
> 
> --
> Greg