[Qemu-devel] [RFC v3 0/2] Add live migration support in the PVRDMA device

[Sukrit Bhatnagar]

In v2, we had successful migration of PCI and MSIX states as well as
various DMA addresses and ring page information.
This series enables the migration of various GIDs used by the device.

We have switched to a setup having two hosts and two VMs running atop them.
Migrations are now performed over the local network. This has settled the
same-host issue with libvirt.

We also have performed various ping-pong tests (ibv_rc_pingpong) in the
guest(s) after adding GID migration support and this is the current status:
- ping-pong to localhost succeeds, when performed before starting the
  migration and after the completion of migration.
- ping-pong to a peer succeeds, both before and after migration as above,
  provided that both VMs are running on/migrated to the same host.
  So, if two VMs were started on two different hosts, and one of them
  was migrated to the other host, the ping-pong was successful.
  Similarly, if two VMs are migrated to the same host, then after migration,
  the ping-pong was successful.
- ping-pong to a peer on the remote host is not working as of now.

Our next goal is to achieve successful migration with live traffic.

This series can be also found at:
https://github.com/skrtbhtngr/qemu/tree/gsoc19


History:

v2 -> v3:
- remove struct PVRDMAMigTmp and VMSTATE_WITH_TMP
- use predefined PVRDMA_HW_NAME for the vmsd name
- add vmsd for gids and a gid table field in pvrdma_state
- perform gid registration in pvrdma_post_load
- define pvrdma_post_save to unregister gids in the source host

v1 -> v2:
- modify load_dsr() to make it idempotent
- switch to VMStateDescription
- add fields for PCI and MSIX state
- define a temporary struct PVRDMAMigTmp to use WITH_TMP macro
- perform mappings to CQ and event notification rings at load
- vmxnet3 issue solved by Marcel's patch
- BounceBuffer issue solved automatically by switching to VMStateDescription


Link(s) to v2:
https://lists.gnu.org/archive/html/qemu-devel/2019-07/msg01848.html
https://lists.gnu.org/archive/html/qemu-devel/2019-07/msg01849.html
https://lists.gnu.org/archive/html/qemu-devel/2019-07/msg01850.html

Link(s) to v1:
https://lists.gnu.org/archive/html/qemu-devel/2019-06/msg04924.html
https://lists.gnu.org/archive/html/qemu-devel/2019-06/msg04923.html

Sukrit Bhatnagar (2):
  hw/pvrdma: make DSR mapping idempotent in load_dsr()
  hw/pvrdma: add live migration support

 hw/rdma/vmw/pvrdma_main.c | 94 +++++++++++++++++++++++++++++++++++----
 1 file changed, 86 insertions(+), 8 deletions(-)

-- 
2.21.0