The playback and record channel send SPICE_MSG_MIGRATE to the client.
Both playback and record channel does not have a state to restore:
while in the legacy migration implementation the record channel
used to restore the mode and start time, it looks unnecessary since
the client receives from the src MSG_RECORD_STOP before the migration
completion notification (when the vm is stopped). Afterwards, when the vm
starts on the dest side, the client receives MSG_RECORD_START.
Due to the fix in the previous patch, snd_disconnect_channel can be
called both when there is write/read error in the channel, or from
red_client_destroy (which calls client_cbs.disconnect).
Multiple calls to snd_disconnect_channel resulted in calling
channel->cleanup(channel) more than once (double release).
snd channel wasn't added to be part of the client's channels list.
As a result, when the client was destroyed, or migrated, snd channel
client wasn't destroy, or its migration callback wasn't called.
However, due to adding dummy channels to the client, we need special
handling for calls to disconnecting dummy channel clients.
TODO: we need to refactor snd_worker to use red_channel
A channel pipe item type must start from PIPE_ITEM_TYPE_CHANNEL_BASE.
SPICE_MSG_MIGRATE value eq. PIPE_ITEM_TYPE_SET_ACK. Setting a pipe item
type to SPICE_MSG_MIGRATE, leads to red_channel handling PIPE_ITEM_TYPE_SET_ACK.
If reading/writing from the device have occured before migration data
has arrived, the migration data might no longer be relvant, and we
disconnect the client.
Before sending the above msg, if there is a pending partial msg that
has been read from the agent, we send it to the client. The alternative
was to keep the msg as part of the migration data, and then
to send it to the destination server via the client and to wait there
for the msg chunk completion, before sending it to the client. Of
course, the latter is less efficient.
A channel pipe item type must start from PIPE_ITEM_TYPE_CHANNEL_BASE.
SPICE_MSG_MIGRATE value eq. PIPE_ITEM_TYPE_SET_ACK. Setting a pipe item
type to SPICE_MSG_MIGRATE, leads to red_channel handling PIPE_ITEM_TYPE_SET_ACK.
Also removed sending SPICE_MSG_MIGRATE. It will be handled in the next
patch.
Attach/detach a client to a SpiceCharDeviceState upon its
connection/disconnection, instead of upon reader_add/remove messages.
When the client is removed from a SpiceCharDeviceState, all the
messages from this client are removed from the device write queue.
This shouldn't happen when we only receive reader_remove and the
client is still connected.
When restoring migration data, we also restore data that is addressed to
the device, and that might have been originated from more than 1
message. When the write buffer that is assoicated with this data is
released, we need to free all the relevant tokens.
Tracking the channels that wait for migration data. If there
is a new migration process pending, when all the channels have
restored their state, we begin the new migration.
In semi-seamless, SPICE_MSG_MAIN_MIGRATE_END is sent.
In seamless, each channel migrates separately.
The src waits till all the clients are disconnected (or a timeout), and
then it notifies qemu that spice migration has completed.
The patch doesn't include the per-channel logic for seamless migration
(sending MSG_MIGRATE, MIGRATE_DATA, etc.).
- handle SPICE_MSGC_MAIN_MIGRATE_DST_DO_SEAMLESS
- reply with SPICE_MSG_MAIN_MIGRATE_DST_SEAMLESS_ACK/NACK
- prepare the channels for migration according to the migration
type (semi/seamless)
see spice-protocol for more details:
commit 3838ad140a046c4ddf42fef58c9727ecfdc09f9f
sending SPICE_MSG_MAIN_MIGRATE_BEGIN_SEAMLESS and handling
SPICE_MSGC_MAIN_MIGRATE_CONNECTED_SEAMLESS
The src side signals the client to establish a connection
to the destination.
In seamless migration, the client is also used to perform
a sort of handshake with the destination, for verifying
if seamless migration can be supported.
see spice-protocol for more details:
commit 3838ad140a046c4ddf42fef58c9727ecfdc09f9f
The file will hold the declarations of the different migration
data messages (depending on the channel), that will be passed
from the src server to the dst server, via the client, using
SPICE_MSG_MIGRATE_DATA.
This new call is used in order to identify whether qemu, or
the management (e.g. libvirt), support seamless migration.
If it is supported, qemu spice cmd-line configuration should have
seamless-migration=on.
In addition, we disable seamless migration support if multiple clients
are allowed. Currently, only one client is supported.
Till now, red_worker was notfied about vm status changes via QXLWorker->start/stop
(or spice_qxl_start/stop).
Newer qemu, that supports calling spice_server_vm_start/stop, will call only
these routines, and won't call QXLWorker->start/stop.
When vm state changes (started/stopped), we notify all the
attached SpiceCharDeviceStates about the change. This is mainly required
for avoiding writing/reading to/from the device during the non-live
stage of migration.
spice version will be bumped in one of the following patches.
The list of attached char_devices will be used in the next patch
for notifying each instance of SpiceCharDeviceState when the vm
is started or stopped.
