[Qemu-devel] [PATCH v2 00/12] Remove RDMA migration dependence on RAMBlock offset

[Dr. David Alan Gilbert (git)]

From: "Dr. David Alan Gilbert" <address@hidden>

RDMA migration currently relies on the source and destination RAMBlocks
having the same offsets within ram_addr_t space;  unfortunately that's
just not true when:
   a) You hotplug on the source but then create the device on the command line
     on the destination.

   b) Across two versions of qemu

Thus there are migrations that work with TCP that don't with RDMA.

The changes keep stream compatibility with existing RDMA migration,
so cases that already work (i.e. no hotplug) will keep working.

The new requirements do rely on the block indexes being the same on
both sides (hence we sort to ensure that), my reading of the existing
code is that it also relies on that in various places but doesn't ensure
it's true.

With some light testing this seems to work; hopefully I've got all the
cases that pass offsets back and forward.

v2:
  Keep rdma_delete_block's ability to delete entries from the hash
     (on the source side)
  Fix ram-control-hook modification so they don't break non-rdma migrate
  Added a fix that makes the RDMA migration exit in the case of some mismatched
    configs instead of hanging.
  Clarified comments/commit messages
  Added a pair of typo fixes

Dr. David Alan Gilbert (12):
  Rename RDMA structures to make destination clear
  qemu_ram_foreach_block: pass up error value, and down the ramblock
    name
  Remove unneeded memset
  rdma typos
  Store block name in local blocks structure
  Translate offsets to destination address space
  Rework ram_control_load_hook to hook during block load
  Allow rdma_delete_block to work without the hash
  Rework ram block hash
  Sort destination RAMBlocks to be the same as the source
  Sanity check RDMA remote data
  Fail more cleanly in mismatched RAM cases

 arch_init.c                   |   4 +-
 exec.c                        |  10 +-
 include/exec/cpu-common.h     |   4 +-
 include/migration/migration.h |   2 +-
 include/migration/qemu-file.h |  14 +-
 migration/qemu-file.c         |  16 +-
 migration/rdma.c              | 347 +++++++++++++++++++++++++++++-------------
 trace-events                  |  12 +-
 8 files changed, 279 insertions(+), 130 deletions(-)

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2.4.2