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Currently only have test cover for virtiofsd (which I know uses the DEVICE_STATE extension). The I've also done a lot of manual testing with virtiofsd and this works well. |
alyssais
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Each vhost-user device type had near identical State structs. Deduplicate those by introducing a new common struct (and parameterising it when it needs to embed a config member.) This will make it easier to reuse more code in the future and to add more struct members to handle the requirements of snapshot/restore. These changes have been designed to have no impact on the existing snapshot/restore state. Signed-off-by: Rob Bradford <[email protected]>
With a common state structure for all vhost-user devices the state() methods can also be refactored for reuse. This will make it easier to add new common fields in the future for snapshot/restore. Signed-off-by: Rob Bradford <[email protected]>
In GenericVhostUser's read_config and write_config, access vu_common.acked_protocol_features directly instead of going through the state() method which creates a struct. This removes creating the struct just to access two fields that are already directly accessible. Signed-off-by: Rob Bradford <[email protected]>
This is a refactoring step in preparation for fetching backend device state via SET_DEVICE_STATE_FD which can fail. Signed-off-by: Rob Bradford <[email protected]>
Rename update_supports_migration() to update_supported_features() as this method will be extended to track additional capability flags beyond just migration support (e.g. DEVICE_STATE for snapshot/restore.) Signed-off-by: Rob Bradford <[email protected]>
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sboeuf
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The vhost-user protocol now has support for the backend to provide an opaque blob of data (read or written through a pipe) that the VMM can use to save/restore state after snapshot/restore or live migration. It also adds a command for checking the backend accepts the uploaded device state. One quirk of saving the state is that GET_VRING_BASE must be used first to quiesce the state of the backend and flush any in-flight requests. This then also requires saving that index for use on the restore. Signed-off-by: Rob Bradford <[email protected]>
Fetch the opaque device state from the backend and store it along with the last vring used in the state used for the snapshot. Signed-off-by: Rob Bradford <[email protected]>
Add a common method for validating the state (checking vrings & device_state) and then restoring the backend state if present. Signed-off-by: Rob Bradford <[email protected]>
Enable the DEVICE_STATE protocol feature negotiation for all vhost-user devices (block, fs, net, and generic). Restoring the state (including the backend state if present) and vrings. Signed-off-by: Rob Bradford <[email protected]>
Add test_snapshot_restore_virtio_fs which validates that virtio-fs continues to work correctly across a snapshot/restore cycle. Signed-off-by: Rob Bradford <[email protected]>
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See: #7850