[Qemu-devel] [PATCH 0/17 v5] Localhost migration with side channel for ram

[Lei Li <lilei@linux.vnet.ibm.com>]

This patch series tries to introduce a mechanism using side
channel pipe for RAM via SCM_RIGHTS with unix domain socket
protocol migration.

This side channel is used for the page flipping by vmsplice,
which is the internal mechanism for localhost migration that
we are trying to add to QEMU. The backgroud info and previous
patch series for reference,

Localhost migration
http://lists.nongnu.org/archive/html/qemu-devel/2013-08/msg02916.html

migration: Introduce side channel for RAM
http://lists.gnu.org/archive/html/qemu-devel/2013-09/msg04043.html

I have picked patches from the localhost migration series and rebased 
it on the series of side channel, now it is a complete series that
passed the basic test.

Please let me know if there is anything needs to be fixed or improved.
Your suggestions and comments are very welcome, and thanks to Paolo
for his continued review and useful suggestions.


Changes since V4:
  Rename the capability to x-unix-page-flipping for now. (Paolo)

Changes since V3:
  Address comments from Paolo including:

    - Get rid of useless check in send_pipefd() and the override
      of before_ram_iterate, send pipefd in the first save_page
      call, qemu_get_byte() in the first ram_load correspondingly.
    - Add new argument ram_addr_t to hook_ram_load to cut half of
      the data transferred on the socket.
    - Add transition from 'debug' to 'memory-stale'.
    - Other minor fixes.

Changes since V2:
  Address comments from Paolo including:

    - Doc improvement for QAPI.
    - Use callback get_buffer as the only one receiver.
    - Rename the new RunState flipping-migrate to memory-stale, and
      add transition from 'prelaunch' to 'memory-stale'.
    - Other minor fixes.

Changes since V1:
  Address suggestions from Paolo Bonzini including:

    - Use Unix socket QEMUFile as basis of code and adjust the way
      of overriding RDMA hooks.
    - Involve the vmsplice for page flipping.
    - Add new RunState RUN_STATE_FLIPPING_MIGRATE and add it to
      runstate_needs_reset() for the adjustment of the current
      migration process with page flipping.



Lei Li (17):
  QAPI: introduce magration capability unix_page_flipping
  migration: add migrate_unix_page_flipping()
  qmp-command.hx: add missing docs for migration capabilites
  migration-local: add QEMUFileLocal with socket based QEMUFile
  migration-local: introduce qemu_fopen_socket_local()
  migration-local: add send_pipefd()
  save_page: replace block_offset with a MemoryRegion
  migration-local: override save_page for page transmit
  savevm: adjust ram_control_save_page with page flipping
  add unix_msgfd_lookup() to callback get_buffer
  add argument ram_addr_t to hook_ram_load
  migration-local: override hook_ram_load 
  migration-unix: replace qemu_fopen_socket with qemu_fopen_socket_local
  add new RanState RAN_STATE_MEMORY_STALE
  migration-unix: page flipping support on unix outgoing
  migration: adjust migration_thread() process for unix_page_flipping
  hmp: better format for info migrate_capabilities

 Makefile.target               |   1 +
 arch_init.c                   |   4 +-
 migration-local.c             | 512 ++++++++++++++++++++++++++++++++++++++++++
 hmp.c                         |   5 +-
 include/migration/migration.h |   3 +
 include/migration/qemu-file.h |   2 +
 migration-unix.c              |  27 ++-
 migration-rdma.c              |   4 +-
 migration.c                   |  18 +-
 qapi-schema.json              |  18 +-
 qmp-commands.hx               |   8 +
 savevm.c                      |  21 +-
 vl.c                          |  12 +-
 13 files changed, 617 insertions(+), 27 deletions(-)
 create mode 100644 migration-local.c