Re: [Qemu-devel] [PATCH] qemu: Introduce VIRTIO_NET_F_STANDBY feature bit to virtio_net

[Jason Wang]

On 2018年06月05日 09:41, Samudrala, Sridhar wrote:
> Ping on this patch now that the kernel patches are accepted into 
> davem's net-next tree.
> https://patchwork.ozlabs.org/cover/920005/
>
>
> On 5/7/2018 4:09 PM, Sridhar Samudrala wrote:
> > This feature bit can be used by hypervisor to indicate virtio_net 
> > device to
> > act as a standby for another device with the same MAC address.
> >
> > I tested this with a small change to the patch to mark the STANDBY 
> > feature 'true'
> > by default as i am using libvirt to start the VMs.
> > Is there a way to pass the newly added feature bit 'standby' to qemu 
> > via libvirt
> > XML file?

Maybe you can try qemu command line passthrough:

https://libvirt.org/drvqemu.html#qemucommand

The patch looks good to me. Let's see if Michael have any comment.

Thanks

> > Signed-off-by: Sridhar Samudrala <address@hidden>
> > ---
> >   hw/net/virtio-net.c                         | 2 ++
> >   include/standard-headers/linux/virtio_net.h | 3 +++
> >   2 files changed, 5 insertions(+)
> >
> > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> > index 90502fca7c..38b3140670 100644
> > --- a/hw/net/virtio-net.c
> > +++ b/hw/net/virtio-net.c
> > @@ -2198,6 +2198,8 @@ static Property virtio_net_properties[] = {
> >                        true),
> >       DEFINE_PROP_INT32("speed", VirtIONet, net_conf.speed, 
> > SPEED_UNKNOWN),
> >       DEFINE_PROP_STRING("duplex", VirtIONet, net_conf.duplex_str),
> > +    DEFINE_PROP_BIT64("standby", VirtIONet, host_features, 
> > VIRTIO_NET_F_STANDBY,
> > +                      false),
> >       DEFINE_PROP_END_OF_LIST(),
> >   };
> >   diff --git a/include/standard-headers/linux/virtio_net.h 
> > b/include/standard-headers/linux/virtio_net.h
> > index e9f255ea3f..01ec09684c 100644
> > --- a/include/standard-headers/linux/virtio_net.h
> > +++ b/include/standard-headers/linux/virtio_net.h
> > @@ -57,6 +57,9 @@
> >                        * Steering */
> >   #define VIRTIO_NET_F_CTRL_MAC_ADDR 23    /* Set MAC address */
> >   +#define VIRTIO_NET_F_STANDBY      62    /* Act as standby for 
> > another device
> > +                                         * with the same MAC.
> > +                                         */
> >   #define VIRTIO_NET_F_SPEED_DUPLEX 63    /* Device set linkspeed and 
> > duplex */
> >     #ifndef VIRTIO_NET_NO_LEGACY