[PATCH v12 00/10] migration: Modify 'migrate' and 'migrate-incoming' QAPI commands for migration

[Het Gala]

This is v12 patchset of modified 'migrate' and 'migrate-incoming' QAPI design
for upstream review.

Would like to thank all the maintainers that actively participated in the v11
patchset discussion and gave insightful suggestions to improve the patches.

Link to previous upstream community patchset links:
v1: https://lists.gnu.org/archive/html/qemu-devel/2022-12/msg04339.html
v2: https://lists.gnu.org/archive/html/qemu-devel/2023-02/msg02106.html
v3: https://lists.gnu.org/archive/html/qemu-devel/2023-02/msg02473.html
v4: https://lists.gnu.org/archive/html/qemu-devel/2023-05/msg03064.html
v5: https://lists.gnu.org/archive/html/qemu-devel/2023-05/msg04845.html
v6: https://lists.gnu.org/archive/html/qemu-devel/2023-06/msg01251.html
v7: https://lists.gnu.org/archive/html/qemu-devel/2023-07/msg02027.html
v8: https://lists.gnu.org/archive/html/qemu-devel/2023-07/msg02770.html
v9: https://lists.gnu.org/archive/html/qemu-devel/2023-07/msg04216.html
v10: https://lists.gnu.org/archive/html/qemu-devel/2023-07/msg05022.html
v11: https://lists.gnu.org/archive/html/qemu-devel/2023-10/msg00740.html

v11 -> v12 changelog:
-------------------
- Resolved double-freeing when using g_autoptr in structures that are
  nested into another.
- Overwriting of pointers to an existing allocated memory is solved at
  various places.
- Use of g_autoptr caused make check errors in non-error path while going
  out of scope inside function. Added g_steal_pointer() in the non-error
  paths wherever required.

Abstract:
---------

Current QAPI 'migrate' command design (for initiating a migration
stream) contains information regarding different migrate transport mechanism
(tcp / unix / exec), dest-host IP address, and binding port number in form of
a string. Thus the design does seem to have some design issues. Some of the
issues, stated below are:

1. Use of string URIs is a data encoding scheme within a data encoding scheme.
   QEMU code should directly be able to work with the results from QAPI,
   without resorting to do a second level of parsing (eg. socket_parse()).
2. For features / parameters related to migration, the migration tunables needs
   to be defined and updated upfront. For example, 'migrate-set-capability'
   and 'migrate-set-parameter' is required to enable multifd capability and
   multifd-number of channels respectively. Instead, 'Multifd-channels' can
   directly be represented as a single additional parameter to 'migrate'
   QAPI. 'migrate-set-capability' and 'migrate-set-parameter' commands could
   be used for runtime tunables that need setting after migration has already
   started.

The current patchset focuses on solving the first problem of multi-level
encoding of URIs. The patch defines 'migrate' command as a QAPI discriminated
union for the various transport backends (like socket, exec and rdma), and on
basis of transport backends, different migration parameters are defined.

(uri) string -->  (channel) Channel-type
                            Transport-type
                            Migration parameters based on transport type
------------------------------------------------------------------------------

Het Gala (10):
  migration: New QAPI type 'MigrateAddress'
  migration: convert migration 'uri' into 'MigrateAddress'
  migration: convert socket backend to accept MigrateAddress
  migration: convert rdma backend to accept MigrateAddress
  migration: convert exec backend to accept MigrateAddress.
  migration: New migrate and migrate-incoming argument 'channels'
  migration: modify migration_channels_and_uri_compatible() for new QAPI
    syntax
  migration: Implement MigrateChannelList to qmp migration flow.
  migration: Implement MigrateChannelList to hmp migration flow.
  migration: modify test_multifd_tcp_none() to use new QAPI syntax.

 migration/exec.c               |  74 +++++++++----
 migration/exec.h               |   8 +-
 migration/migration-hmp-cmds.c |  17 ++-
 migration/migration.c          | 189 +++++++++++++++++++++++++++------
 migration/migration.h          |   3 +-
 migration/rdma.c               |  34 +++---
 migration/rdma.h               |   6 +-
 migration/socket.c             |  39 ++-----
 migration/socket.h             |   7 +-
 qapi/migration.json            | 150 +++++++++++++++++++++++++-
 softmmu/vl.c                   |   2 +-
 tests/qtest/migration-test.c   |   7 +-
 12 files changed, 412 insertions(+), 124 deletions(-)

-- 
2.22.3