CVQ of net vhost-vdpa devices can be intercepted since the work of [1]. 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 fixes [1], [2] and [3] to be applied to achieve full live migration. Thanks! [1] https://lists.nongnu.org/archive/html/qemu-devel/2022-07/msg02984.html [2] https://lists.nongnu.org/archive/html/qemu-devel/2022-07/msg03993.html [3] https://lists.nongnu.org/archive/html/qemu-devel/2022-08/msg00325.html 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 (10): vhost: stop transfer elem ownership in vhost_handle_guest_kick vhost: use SVQ element ndescs instead of opaque data for desc validation vhost: Do not depend on !NULL VirtQueueElement on vhost_svq_flush vdpa: Get buffers from VhostVDPAState on vhost_vdpa_net_cvq_map_elem vdpa: Extract vhost_vdpa_net_cvq_add from vhost_vdpa_net_handle_ctrl_avail vdpa: Make vhost_vdpa_net_cvq_map_elem accept any out sg vdpa: add NetClientState->load() callback vdpa: add net_vhost_vdpa_cvq_info NetClientInfo 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 | 2 + hw/net/vhost_net.c | 7 ++ hw/virtio/vhost-shadow-virtqueue.c | 31 +++--- hw/virtio/vhost-vdpa.c | 14 --- net/vhost-vdpa.c | 163 +++++++++++++++++++++-------- 6 files changed, 145 insertions(+), 73 deletions(-) -- 2.31.1
