diff options
Diffstat (limited to 'docs/devel')
| -rw-r--r-- | docs/devel/migration/vfio.rst | 19 |
1 files changed, 17 insertions, 2 deletions
diff --git a/docs/devel/migration/vfio.rst b/docs/devel/migration/vfio.rst index d6cf60890c..a803a09bc1 100644 --- a/docs/devel/migration/vfio.rst +++ b/docs/devel/migration/vfio.rst @@ -71,11 +71,23 @@ VFIO implements the device hooks for the iterative approach as follows: reassembles the multifd received data and loads it in-order into the device. In the non-multifd mode this function is a NOP. -* A ``save_state`` function to save the device config space if it is present. +* A ``save_state`` function to save the device config space if it is present + in the non-multifd mode. + In the multifd mode it just emits either a dummy EOS marker. * A ``save_live_complete_precopy`` function that sets the VFIO device in _STOP_COPY state and iteratively copies the data for the VFIO device until the vendor driver indicates that no data remains. + In the multifd mode it just emits a dummy EOS marker. + +* A ``save_live_complete_precopy_thread`` function that in the multifd mode + provides thread handler performing multifd device state transfer. + It sets the VFIO device to _STOP_COPY state, iteratively reads the data + from the VFIO device and queues it for multifd transmission until the vendor + driver indicates that no data remains. + After that, it saves the device config space and queues it for multifd + transfer too. + In the non-multifd mode this thread is a NOP. * A ``load_state`` function that loads the config section and the data sections that are generated by the save functions above. @@ -184,8 +196,11 @@ Live migration save path Then the VFIO device is put in _STOP_COPY state (FINISH_MIGRATE, _ACTIVE, _STOP_COPY) .save_live_complete_precopy() is called for each active device - For the VFIO device, iterate in .save_live_complete_precopy() until + For the VFIO device: in the non-multifd mode iterate in + .save_live_complete_precopy() until pending data is 0 + In the multifd mode this iteration is done in + .save_live_complete_precopy_thread() instead. | (POSTMIGRATE, _COMPLETED, _STOP_COPY) Migraton thread schedules cleanup bottom half and exits |