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Diffstat (limited to 'docs')
| -rw-r--r-- | docs/devel/migration/vfio.rst | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/docs/devel/migration/vfio.rst b/docs/devel/migration/vfio.rst index a803a09..673e354 100644 --- a/docs/devel/migration/vfio.rst +++ b/docs/devel/migration/vfio.rst @@ -232,3 +232,18 @@ Postcopy ======== Postcopy migration is currently not supported for VFIO devices. + +Multifd +======= + +Starting from QEMU version 10.0 there's a possibility to transfer VFIO device +_STOP_COPY state via multifd channels. This helps reduce downtime - especially +with multiple VFIO devices or with devices having a large migration state. +As an additional benefit, setting the VFIO device to _STOP_COPY state and +saving its config space is also parallelized (run in a separate thread) in +such migration mode. + +The multifd VFIO device state transfer is controlled by +"x-migration-multifd-transfer" VFIO device property. This property defaults to +AUTO, which means that VFIO device state transfer via multifd channels is +attempted in configurations that otherwise support it. |