[libvirt PATCH] Adds e1000e/vmxnet3 Vnet_hdr suuport

[Patrick J. Magauran]

On Fri, 2020-08-07 at 17:16 +0100, Daniel P. Berrangé wrote:
> On Thu, Aug 06, 2020 at 10:53:32PM -0400, Patrick Magauran wrote:
> > Libvirt bases its decision about whether to apply the vnet_hdr flag
> > to the tap interface on whether or not the selected model is
> > VirtIO. Originally, VirtIO was the only model to support the
> > vnet_hdr in QEMU; however, the e1000e & vmxnet3 adapters also
> > support it(seemingly from introduction based on commits). This
> > passes the whole packet to the host, reducing emulation overhead
> > and improving performance.
> > 
> > Signed-off-by: Patrick Magauran <patmagauran.j at gmail.com>
> > ---
> >  src/conf/domain_conf.c    | 8 +++++++-
> >  src/conf/domain_conf.h    | 1 +
> >  src/libvirt_private.syms  | 1 +
> >  src/qemu/qemu_interface.c | 8 ++++----
> >  4 files changed, 13 insertions(+), 5 deletions(-)
> > 
> > diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
> > index 69e0439e7e..cb184110f7 100644
> > --- a/src/conf/domain_conf.c
> > +++ b/src/conf/domain_conf.c
> > @@ -30981,7 +30981,13 @@ virDomainNetIsVirtioModel(const
> > virDomainNetDef *net)
> >              net->model == VIR_DOMAIN_NET_MODEL_VIRTIO_TRANSITIONAL
> > ||
> >              net->model ==
> > VIR_DOMAIN_NET_MODEL_VIRTIO_NON_TRANSITIONAL);
> >  }
> > -
> > +bool
> > +virDomainNetIsVnetCompatModel(const virDomainNetDef *net)
> > +{
> > +    return (virDomainNetIsVirtioModel(net) ||
> > +            net->model == VIR_DOMAIN_NET_MODEL_E1000E ||
> > +            net->model == VIR_DOMAIN_NET_MODEL_VMXNET3);
> > +}
> 
> Should really live in the qemu_inteface.c file,  with
> a qemuOnterfaceIsVnetCompatModel name, since the decision
> is inherantly tied to QEMU, and inappropriate for other
> virt drivers.
> 
> 
> Regards,
> Daniel

I would think the qemu_interface.c file is more for the actual setup
functionality rather than simple helper functions. Would the
qemu_domain.c file make for sense?

--Patrick