On 2/17/26 14:05, Avihai Horon wrote:
On 2/16/2026 7:40 PM, Cédric Le Goater wrote:
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On 2/16/26 14:25, Avihai Horon wrote:
On 2/16/2026 2:22 PM, Cédric Le Goater wrote:
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Peter, Avihai,
As for enabling the VFIO migration events by default, I guess we
all agree it could be done. We simply need a stakeholder to change
the default behavior.
Ack.
There could be value for the sysmgmt layers to receive a VFIO
migration event reporting progress. For example, an event could
be sent from vfio_save_iterate() including relevant size metrics
to indicate progress (or not).
Any opinions ?
Amm, I am not sure an event is the right way to report VFIO stats, as it's not
some change that mgmt needs to be notified about promptly.
Mgmt layer can query migration stats when needed using the QMP 'query-migrate'
command that returns, among other info, a VfioStats struct with the total
amount of VFIO devices data transferred. If needed, this can be extended with
more info about remaining data size, etc.
Makes sense?
so you would opt to extend migration_populate_vfio_info() with more
info on the VFIO devices. Fine. mgmt should poll then. My knowledge
on these layers is limited.
The extra info would be "precopy initial" and "precopy dirty" sizes
I suppose. Per device (more complex) or overall ?
I think per device would be more helpful.
Yeah I think too.
Extending migration_populate_vfio_info() could be a nice add, but
I am not sure how is this related to this patch I sent?
I was just extending the discussion, thinking aloud. Sorry for the
confusion.
This patch is in vfio-next. I am waiting for Ankit to respin its
series and I will send a PR.
Or we're discussing this because you initially thought that this
could be a reason to enable vfio events by default?
It could be a reason but it really depends on how the sysmgmt layer
wants to consume the info.
Users have been requesting more fine-grained VFIO information to
improve the migration flow. Leveraging VfioStats seems to be the
safest approach for that today.
Thanks,
C.
