> From: Qemu-devel bounces+yishaih=nvidia@nongnu.org> On Behalf Of Juan Quintela
> Sent: Monday, 3 October 2022 6:16
> To: qemu-de...@nongnu.org
> Cc: Alex Williamson ; Eric Blake
> ; Stefan Hajnoczi ; Fam
> Zheng ; qemu-s3...@nongnu.org; Cornelia Huck
> ; Thomas Huth ; Vladimir
> Sementsov-Ogievskiy ; Laurent Vivier
> ; John Snow ; Dr. David Alan
> Gilbert ; Christian Borntraeger
> ; Halil Pasic ; Juan
> Quintela ; Paolo Bonzini ;
> qemu-block@nongnu.org; Eric Farman ; Richard
> Henderson ; David Hildenbrand
>
> Subject: [RFC 0/7] migration patches for VFIO
>
> Hi
>
> VFIO migration has several requirements:
> - the size of the state is only known when the guest is stopped
As was discussed in the conference call, I just sent a patch to the kernel
mailing list to be able to get the state size in each state.
See:
https://patchwork.kernel.org/project/kvm/patch/20221020132109.112708-1-yish...@nvidia.com/
This can drop the need to stop the guest and ask for that data.
So, I assume that you can drop some complexity and hacks from your RFC once
you'll send the next series.
Specifically,
No need to stop the VM and re-start it in case the SLA can't meet, just read
upon RUNNING the estimated data length that will be required to complete
STOP_COPY and use it.
Yishai
> - they need to send possible lots of data.
>
> this series only address the 1st set of problems.
>
> What they do:
> - res_compatible parameter was not used anywhere, just add that
> information to res_postcopy.
> - Remove QEMUFILE parameter from save_live_pending
> - Split save_live_pending into
> * save_pending_estimate(): the pending state size without trying too hard
> * save_pending_exact(): the real pending state size, it is called with the
> guest stopped.
> - Now save_pending_* don't need the threshold parameter
> - HACK a way to stop the guest before moving there.
>
> ToDo:
> - autoconverge test is broken, no real clue why, but it is possible that the
> test
> is wrong.
>
> - Make an artifact to be able to send massive amount of data in the save
> state stage (probably more multifd channels).
>
> - Be able to not having to start the guest between cheking the state pending
> size and migration_completion().
>
> Please review.
>
> Thanks, Juan.
>
> Juan Quintela (7):
> migration: Remove res_compatible parameter
> migration: No save_live_pending() method uses the QEMUFile parameter
> migration: Block migration comment or code is wrong
> migration: Split save_live_pending() into state_pending_*
> migration: Remove unused threshold_size parameter
> migration: simplify migration_iteration_run()
> migration: call qemu_savevm_state_pending_exact() with the guest
> stopped
>
> docs/devel/migration.rst | 18 ++--
> docs/devel/vfio-migration.rst | 4 +--
> include/migration/register.h | 29 ++-
> migration/savevm.h | 8 +++---
> hw/s390x/s390-stattrib.c | 11 ---
> hw/vfio/migration.c| 17 +--
> migration/block-dirty-bitmap.c | 14 -
> migration/block.c | 17 ++-
> migration/migration.c | 52 ++
> migration/ram.c| 35 ---
> migration/savevm.c | 37 +---
> tests/qtest/migration-test.c | 3 +-
> hw/vfio/trace-events | 2 +-
> migration/trace-events | 7 +++--
> 14 files changed, 148 insertions(+), 106 deletions(-)
>
> --
> 2.37.2
>
