On 03/04/2018 08:05 AM, Yan Vugenfirer wrote: > > >> On 2 Mar 2018, at 22:19, Michael S. Tsirkin <m...@redhat.com >> <mailto:m...@redhat.com>> wrote: >> >> On Fri, Mar 02, 2018 at 03:14:01PM +0800, Jason Wang wrote: >>> >>> >>> On 2018年03月02日 11:46, Jason Baron wrote: >>>> Although linkspeed and duplex can be set in a linux guest via >>>> 'ethtool -s', >>>> this requires custom ethtool commands for virtio-net by default. >>>> >>>> Introduce a new feature flag, VIRTIO_NET_F_SPEED_DUPLEX, which allows >>>> the hypervisor to export a linkspeed and duplex setting. The user can >>>> subsequently overwrite it later if desired via: 'ethtool -s'. >>>> >>>> Linkspeed and duplex settings can be set as: >>>> '-device virtio-net,speed=10000,duplex=full' >>> >>> I was thinking whether or not it's better to decide the duplex by the >>> type >>> of backends. >>> >>> E.g userspace and vhost-kernel implement a in fact half duplex. But dpdk >>> implement a full duplex. >>> >>> Thanks >> >> OTOH it's a priority for some people to be able to support migration >> between different backend types. Breaking that won't be nice. > > I think that in this case we need a way to update the settings of link > speed and link duplex (maybe add QMP command). Migration between > different backend types should cause link down\link up events. And this > is a time for a driver to re-read the settings and update the OS. > > Best regards, > Yan. >
So the virtio_net driver in linux will re-read these settings on link up events. So I could add a qmp command to set these (in addition to the command-line) interface, if desired. Is there a consensus that we need to add a qmp command here? Or can that be treated as a future item, if somebody wants it? Thanks, -Jason
