Re: [PATCH 0/9] migration: Drop/unexport migration_is_device() and migration_is_active()

[Cédric Le Goater]

On 12/16/24 10:46, Avihai Horon wrote:
> Hello,
>
> This follows up on Peter's series [1] to simplify migration status API
> to a single migration_is_running() function.
>
> Peter's series tried to drop migration_is_device() and
> migration_is_active(), however VFIO used them to check if dirty page
> tracking has been started in order to avoid errors in log sync, so they
> couldn't simply be dropped without some preliminary cleanups.
>
> This series handles these preliminary cleanups and eventually drops
> migration_is_device() and unexports migration_is_active().
>
> The series has been migration tested with the following:
> - VFIO device dirty tracking.
> - Legacy VFIO iommu dirty tracking.
> - vIOMMU + Legacy VFIO iommu dirty tracking (migration with vIOMMU is
>    currently blocked, so I used a patched QEMU to allow it).
>
> I didn't test it with iommu DPT as I don't have access to such HW.
> Cedric, I remember you said that you have such HW, it would be very
> helpful if you could test it.

Yes. I can.

I am bit busy now and I only looked quickly at the comments. I understand
from Joao that it shouldn't be too complex to change the VFIO dirty
tracking engines to use calc-dirty-rate, which I agree would useful.

How far are we from that ? We are early in the QEMU cycle and this series
looks ok, may be needs one respin. Should we merge it first ? I feel this
would be good to have before the migration cleanups and the next version
of Maciej's multifd series.


Thanks,

C.





> Patch structure:
> 1-6: Refactor and clean up VFIO dirty page tracking helpers.
> 7: Refactor dirty limit code.
> 8-9: Drop/unexport migration_is_device() and migration_is_running().
>
> Thanks.
>
> [1]
> https://lore.kernel.org/qemu-devel/20241024213056.1395400-1-peterx@redhat.com/
>
> Avihai Horon (9):
>    vfio/container: Add dirty tracking started flag
>    vfio/migration: Refactor vfio_devices_all_dirty_tracking() logic
>    vfio/migration: Refactor vfio_devices_all_running_and_mig_active()
>      logic
>    vfio/migration: Add vfio_devices_all_dirty_tracking_started() helper
>    vfio/migration: Drop vfio_dma_unmap_dirty_sync_needed()
>    vfio/migration: Rename vfio_devices_all_dirty_tracking()
>    system/dirtylimit: Don't use migration_is_active()
>    migration: Drop migration_is_device()
>    migration: Unexport migration_is_active()
>
>   include/hw/vfio/vfio-common.h         |  4 +-
>   include/hw/vfio/vfio-container-base.h |  1 +
>   include/migration/misc.h              |  2 -
>   hw/vfio/common.c                      | 61 ++++++++++++---------------
>   hw/vfio/container-base.c              |  8 +++-
>   hw/vfio/container.c                   |  2 +-
>   migration/migration.c                 | 23 ++++------
>   system/dirtylimit.c                   |  3 +-
>   8 files changed, 48 insertions(+), 56 deletions(-)