Re: [RFC PATCH 0/6] Enable vdpa net migration with features depending on CVQ

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Jul 06, 2023 at 09:12:21PM +0200, Eugenio Pérez wrote:
> At this moment the migration of net features that depends on CVQ is not
> possible, as there is no reliable way to restore the device state like mac
> address, number of enabled queues, etc to the destination.  This is mainly
> caused because the device must only read CVQ, and process all the commands
> before resuming the dataplane.
> 
> This RFC lift that requirement, sending the VHOST_VDPA_SET_VRING_ENABLE ioctl
> for dataplane vqs only after the device has processed all commands.  If this
> method is valid or not, or if it must be signalled by the parent driver
> somehow, is still under discussion.  In case it is valid, this code allows
> testing the vDPA device for it.

And you plan to add the reset trick too in a future version?

> Eugenio Pérez (6):
>   vdpa: export vhost_vdpa_set_vring_ready
>   vdpa: add should_enable op
>   vdpa: use virtio_ops->should_enable at vhost_vdpa_set_vrings_ready
>   vdpa: add stub vhost_vdpa_should_enable
>   vdpa: delay enable of data vqs
>   vdpa: remove net cvq migration blocker
> 
>  include/hw/virtio/vhost-vdpa.h |  9 +++++++
>  hw/virtio/vhost-vdpa.c         | 33 +++++++++++++++++++------
>  net/vhost-vdpa.c               | 45 +++++++++++++++++++++++++---------
>  hw/virtio/trace-events         |  2 +-
>  4 files changed, 68 insertions(+), 21 deletions(-)
> 
> -- 
> 2.39.3
>