On Fri, Aug 06, 2021 at 08:55:56AM +0000, Parav Pandit wrote:
>
>
> > From: Michael S. Tsirkin <mst@xxxxxxxxxx>
> > Sent: Friday, August 6, 2021 2:12 PM
>
>
> > > enum vdpa_attr {
> > > @@ -33,6 +34,16 @@ enum vdpa_attr {
> > > VDPA_ATTR_DEV_MAX_VQS, /* u32 */
> > > VDPA_ATTR_DEV_MAX_VQ_SIZE, /* u16 */
> > > + VDPA_ATTR_DEV_NET_CFG_MACADDR, /* binary */
> > > + VDPA_ATTR_DEV_NET_STATUS, /* u8 */
> > > + VDPA_ATTR_DEV_NET_CFG_MAX_VQP, /* u16 */
> > > + VDPA_ATTR_DEV_NET_CFG_MTU, /* u16 */
> > > + VDPA_ATTR_DEV_NET_CFG_SPEED, /* u16 */
> > > + VDPA_ATTR_DEV_NET_CFG_DUPLEX, /* u16 */
> > > + VDPA_ATTR_DEV_NET_CFG_RSS_MAX_KEY_LEN, /* u8 */
> > > + VDPA_ATTR_DEV_NET_CFG_RSS_MAX_IT_LEN, /* u16 */
> > > + VDPA_ATTR_DEV_NET_CFG_RSS_HASH_TYPES, /* u32 */
> > > +
> > > /* new attributes must be added above here */
> > > VDPA_ATTR_MAX,
> > > };
> >
> > The point is to try and not reinvent a dedicated vpda interface where a
> > generic one exits.
> > E.g. for phy things such as mac speed etc, I think most people are using
> > ethtool things right?
>
> As you know vdpa is the backend device for the front-end netdevice accessed by the ethtool.
> vdpa management tool here is composing the vdpa device.
>
> For example creator (hypervisor) of the vdpa devices knows that a guest VM is given 4 vcpus,
> So hypervisor creates a vdpa devices with config space layout as,
> max_virtqueue_pairs = 4.
> And the MAC address chosen by hypervisor in mac[6].
>
> Guest VM ethtool can still chose to use less number of channels.
>
> Typically,
> ethtool is for guest VM.
> vdpa device is in hypevisor.
>
> How can hypervisor compose a vdpa device without any tool?
> How can it tell ethtool, what is supported and what are the defaults?
>
> I must be misunderstanding your comment about ethtool.
> Can you please explain?
I am basically saying that we probably want to be able to
change MAC of a VDPA device on the host without desroying and recreating the device
as long as it's not in use.
For a VF I can do this on the host:
ip link set eth0 vf 1 mac 00:11:22:33:44:55
ideally same thing would work for vdpa.
--
MST
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