From: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@futurfusion.io>

Dear friends,

This patchset adds basic live migration support for
QEMU emulated NVMe device.

Implementation has some limitations:
- only one NVMe namespace is supported
- SMART counters are not preserved
- CMB is not supported
- PMR is not supported
- SPDM is not supported
- SR-IOV is not supported

I believe this is something I can support in next patchset versions or
separately on-demand (when usecase appears).

Testing.

This patch series was manually tested on:
- Debian 13.3 VM (kernel 6.12.69+deb13-amd64) using fio on *non-root* NVMe disk
  (root disk was virtio-scsi):

time fio --name=nvme-verify \
    --filename=/dev/nvme0n1 \
    --size=5G \
    --rw=randwrite \
    --bs=4k \
    --iodepth=16 \
    --numjobs=1 \
    --direct=0 \
    --ioengine=io_uring \
    --verify=crc32c \
    --verify_fatal=1

- Windows Server 2022 VM (NVMe drive was a *root* disk) with opened browser
  playing video.

No defects were found.

I'm currently working to address feedback from Peter Xu and Klaus Jensen:
- improvements on migration API side to make dynamic arrays support more flexible
- figuring out what is a right way to go with NVMe feature migration capability checks

Changelog for version 3:
- rebased
- simple functional test was added (in accordance with Klaus Jensen's review comment)
  $ meson test 'func-x86_64-nvme_migration' --setup thorough -C build

Changelog for version 2:
- full support for AERs (in-flight requests and queued events too)

Kind regards,
Alex

Alexander Mikhalitsyn (6):
  migration: add VMSTATE_VARRAY_OF_POINTER_TO_STRUCT_UINT{8, 32}_ALLOC
  tests/functional/migration: add VM launch/configure hooks
  hw/nvme: add migration blockers for non-supported cases
  hw/nvme: split nvme_init_sq/nvme_init_cq into helpers
  hw/nvme: add basic live migration support
  tests/functional/x86_64: add migration test for NVMe device

 hw/nvme/ctrl.c                                | 665 +++++++++++++++++-
 hw/nvme/nvme.h                                |   5 +
 hw/nvme/trace-events                          |  11 +
 include/migration/vmstate.h                   |  33 +
 migration/vmstate-types.c                     |  88 +++
 tests/functional/migration.py                 |  22 +-
 tests/functional/x86_64/meson.build           |   1 +
 .../functional/x86_64/test_nvme_migration.py  | 159 +++++
 8 files changed, 951 insertions(+), 33 deletions(-)
 create mode 100755 tests/functional/x86_64/test_nvme_migration.py

-- 
2.47.3