diff options
| author | Maciej S. Szmigiero <maciej.szmigiero@oracle.com> | 2025-03-04 23:03:53 +0100 |
|---|---|---|
| committer | Cédric Le Goater <clg@redhat.com> | 2025-03-06 06:47:34 +0100 |
| commit | 3228d311ab1882f75b04d080d33a71fc7a0bcac5 (patch) | |
| tree | 3189ee2109c686efb16d38c73611571cbdbc377c /docs/devel/migration | |
| parent | 6bcffb1cad5b2b45152c0faa1133c96d3f129914 (diff) | |
| download | qemu-3228d311ab1882f75b04d080d33a71fc7a0bcac5.zip qemu-3228d311ab1882f75b04d080d33a71fc7a0bcac5.tar.gz qemu-3228d311ab1882f75b04d080d33a71fc7a0bcac5.tar.bz2 | |
vfio/migration: Multifd device state transfer support - received buffers queuing
The multifd received data needs to be reassembled since device state
packets sent via different multifd channels can arrive out-of-order.
Therefore, each VFIO device state packet carries a header indicating its
position in the stream.
The raw device state data is saved into a VFIOStateBuffer for later
in-order loading into the device.
The last such VFIO device state packet should have
VFIO_DEVICE_STATE_CONFIG_STATE flag set and carry the device config state.
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/e3bff515a8d61c582b94b409eb12a45b1a143a69.1741124640.git.maciej.szmigiero@oracle.com
[ clg: - Reordered savevm_vfio_handlers
- Added load_state_buffer documentation ]
Signed-off-by: Cédric Le Goater <clg@redhat.com>
Diffstat (limited to 'docs/devel/migration')
| -rw-r--r-- | docs/devel/migration/vfio.rst | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/docs/devel/migration/vfio.rst b/docs/devel/migration/vfio.rst index c49482e..8b1f288 100644 --- a/docs/devel/migration/vfio.rst +++ b/docs/devel/migration/vfio.rst @@ -76,6 +76,10 @@ VFIO implements the device hooks for the iterative approach as follows: * A ``load_state`` function that loads the config section and the data sections that are generated by the save functions above. +* A ``load_state_buffer`` function that loads the device state and the device + config that arrived via multifd channels. + It's used only in the multifd mode. + * ``cleanup`` functions for both save and load that perform any migration related cleanup. @@ -194,6 +198,9 @@ Live migration resume path (RESTORE_VM, _ACTIVE, _STOP) | For each device, .load_state() is called for that device section data + transmitted via the main migration channel. + For data transmitted via multifd channels .load_state_buffer() is called + instead. (RESTORE_VM, _ACTIVE, _RESUMING) | At the end, .load_cleanup() is called for each device and vCPUs are started |