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

[Greg Kurz <gkurz@linux.vnet.ibm.com>]

On Sun, 22 Feb 2015 10:53:51 +0100
"Michael S. Tsirkin" <mst@redhat.com> wrote:
> 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.
> 
> 

Indeed. I will fix tun/macvtap as you suggested.

Thanks for the review.

--
Greg

> 
> > 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
> 

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