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| author | Maciej S. Szmigiero <maciej.szmigiero@oracle.com> | 2025-03-04 23:03:58 +0100 |
|---|---|---|
| committer | Cédric Le Goater <clg@redhat.com> | 2025-03-06 06:47:34 +0100 |
| commit | 623af41dd331d1a57a41bc3374e3d134adb33f4c (patch) | |
| tree | e78c17d5700329f110f707a197a72dbcd78bba51 /docs | |
| parent | 6d644baef20303fa4b2b342f556e26c2262b439f (diff) | |
| download | qemu-623af41dd331d1a57a41bc3374e3d134adb33f4c.zip qemu-623af41dd331d1a57a41bc3374e3d134adb33f4c.tar.gz qemu-623af41dd331d1a57a41bc3374e3d134adb33f4c.tar.bz2 | |
vfio/migration: Add x-migration-multifd-transfer VFIO property
This property allows configuring whether to transfer the particular device
state via multifd channels when live migrating that device.
It defaults to AUTO, which means that VFIO device state transfer via
multifd channels is attempted in configurations that otherwise support it.
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Link: https://lore.kernel.org/qemu-devel/d6dbb326e3d53c7104d62c96c9e3dd64e1c7b940.1741124640.git.maciej.szmigiero@oracle.com
[ clg: Added documentation ]
Signed-off-by: Cédric Le Goater <clg@redhat.com>
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. |