Re: [PATCH v8 00/12] NIC vhost-vdpa state restore via Shadow CVQ

[Eugenio Perez Martin]

On Tue, Aug 9, 2022 at 7:43 PM Eugenio Pérez <eperezma@redhat.com> wrote:
>
> CVQ of net vhost-vdpa devices can be intercepted since the addition of x-svq.
> The virtio-net device model is updated. The migration was blocked because
> although the state can be megrated between VMM it was not possible to restore
> on the destination NIC.
>
> This series add support for SVQ to inject external messages without the 
> guest's
> knowledge, so before the guest is resumed all the guest visible state is
> restored. It is done using standard CVQ messages, so the vhost-vdpa device 
> does
> not need to learn how to restore it: As long as they have the feature, they
> know how to handle it.
>
> This series needs fix [1] to be applied to achieve full live
> migration.
>
> Thanks!
>
> [1] https://lists.nongnu.org/archive/html/qemu-devel/2022-08/msg00325.html
>
> v8:
> - Rename NetClientInfo load to start, so is symmetrical with stop()
> - Delete copy of device's in buffer at vhost_vdpa_net_load
>
> v7:
> - Remove accidental double free.
>
> v6:
> - Move map and unmap of the buffers to the start and stop of the device. This
>   implies more callbacks on NetClientInfo, but simplifies the SVQ CVQ code.
> - Not assume that in buffer is sizeof(virtio_net_ctrl_ack) in
>   vhost_vdpa_net_cvq_add
> - Reduce the number of changes from previous versions
> - Delete unused memory barrier
>
> v5:
> - Rename s/start/load/
> - Use independent NetClientInfo to only add load callback on cvq.
> - Accept out sg instead of dev_buffers[] at vhost_vdpa_net_cvq_map_elem
> - Use only out size instead of iovec dev_buffers to know if the descriptor is
>   effectively available, allowing to delete artificial !NULL VirtQueueElement
>   on vhost_svq_add call.
>
> v4:
> - Actually use NetClientInfo callback.
>
> v3:
> - Route vhost-vdpa start code through NetClientInfo callback.
> - Delete extra vhost_net_stop_one() call.
>
> v2:
> - Fix SIGSEGV dereferencing SVQ when not in svq mode
>
> v1 from RFC:
> - Do not reorder DRIVER_OK & enable patches.
> - Delete leftovers
>
> Eugenio Pérez (12):
>   vhost: stop transfer elem ownership in vhost_handle_guest_kick
>   vhost: use SVQ element ndescs instead of opaque data for desc
>     validation
>   vhost: Delete useless read memory barrier
>   vhost: Do not depend on !NULL VirtQueueElement on vhost_svq_flush
>   vhost_net: Add NetClientInfo prepare callback
>   vhost_net: Add NetClientInfo stop callback
>   vdpa: add net_vhost_vdpa_cvq_info NetClientInfo
>   vdpa: Move command buffers map to start of net device
>   vdpa: extract vhost_vdpa_net_cvq_add from
>     vhost_vdpa_net_handle_ctrl_avail
>   vhost_net: add NetClientState->load() callback
>   vdpa: Add virtio-net mac address via CVQ at start
>   vdpa: Delete CVQ migration blocker
>
>  include/hw/virtio/vhost-vdpa.h     |   1 -
>  include/net/net.h                  |   6 +
>  hw/net/vhost_net.c                 |  17 +++
>  hw/virtio/vhost-shadow-virtqueue.c |  27 ++--
>  hw/virtio/vhost-vdpa.c             |  14 --
>  net/vhost-vdpa.c                   | 225 ++++++++++++++++++-----------
>  6 files changed, 178 insertions(+), 112 deletions(-)
>
> --
> 2.31.1
>
>
>

Hi Jason,

Should I send a new version of this series with the changes you
proposed, or can they be done at pull time? (Mostly changes in patch
messages). Can you confirm to me that there is no other action I need
to perform?

Thanks!