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

From: Greg Kurz
Date: Mon Feb 23 2015 - 08:25:26 EST


On Sun, 22 Feb 2015 10:53:51 +0100
"Michael S. Tsirkin" <mst@xxxxxxxxxx> 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 CÃdric Le Goater:
> >
> > https://www.mail-archive.com/kvm-ppc@xxxxxxxxxxxxxxx/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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