Re: [Qemu-devel] [PATCH 00/19 v2] Add virtio-net/tap support for partial csums and GSO

[Mark McLoughlin <markmc@redhat.com>]

Hi,

On Fri, 2009-10-30 at 11:04 +0100, Juha.Riihimaki@nokia.com wrote:
> On Oct 22, 2009, at 19:43, ext Mark McLoughlin wrote:
> 
> > Hey,
> >        Over a year ago we added some code to qemu-kvm.git which takes
> > advantage of the recent tun/tap IFF_VNET_HDR feature in order to allow
> > virtio-net to send and receive packets with partial checksums and
> > segmentation offloaded:
> >
> >  http://article.gmane.org/gmane.comp.emulators.kvm.devel/20440
> >
> >  "This allows us to pass larger packets and packets with
> >  partial checkums between the guest and the host, greatly
> >  increasing the achievable bandwidth."
> >
> >        Unfortunately, that implementation was quite hacky as it
> > made some assumptions that would break if e.g. you added another
> > network client to a vlan where the feature had enabled.
> >
> >        Now that we have the -netdev parameter, we can more safely
> > pair the NIC and backend, allowing us to negatiate features like
> > this.
> >
> >        What follows is a somewhat cleaned up version of the code
> > from qemu-kvm.git. Further cleanups are probably possible, but I
> > think this much is mergeable. Some points of discussion:
> 
> I think this patch set has broken the QEMU build on OS X. The reason  
> is that there are some definitions in tap-linux.h which only gets  
> included in net.c if __linux__ is defined but the other parts of net.c  
> which utilize definitions from tap-linux.h get compiled in  
> nevertheless. It compiles if all definitions (except for the extra  
> includes) from tap-linux.h are included for OS X as well. I've  
> attached below a sample of the compiler output.

It doesn't look like this is still a problem anymore with latest git?
Could you try again?

There are probably other problems now :-)

Thanks,
Mark.