Commit Graph

45954 Commits

Author SHA1 Message Date
Jiri Denemark
691ce4ea8f qemu: Separate starting migration from qemuMigrationSrcRun
qemuMigrationSrcRun does a lot of thing before and after telling QEMU to
start the migration. Let's make the core reusable by moving it to a new
qemuMigrationSrcStart function.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
d1b6bce02c qemu: Refactor qemuMigrationSrcPerformPhase
To make the code flow a bit more sensible.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
37a67122dd qemu: Implement VIR_MIGRATE_POSTCOPY_RESUME for Begin phase
Mostly we just need to check whether the domain is in a failed post-copy
migration that can be resumed.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
a5e603c808 qemu: Don't set VIR_MIGRATE_PAUSED for post-copy resume
For historical reasons we automatically enabled VIR_MIGRATE_PAUSED flag
when a migration was started for a paused domain. However, when resuming
failed post-copy migration the domain on the source host will always be
paused (as it is already running on the destination host). We must avoid
enabling VIR_MIGRATE_PAUSED in this case.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
6280246971 virsh: Add --postcopy-resume option for migrate command
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
f55aedc845 Introduce VIR_MIGRATE_POSTCOPY_RESUME flag
This flag can be used to restart post-copy migration once it failed
because of a broken connection.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
b3110bb8e4 qemu: Use QEMU_MIGRATION_PHASE_POSTCOPY_FAILED
This phase marks a migration protocol as broken in a post-copy phase.
Libvirt is no longer actively watching the migration in this phase as
the migration API that started the migration failed.

This may either happen when post-copy migration really fails (QEMU
enters postcopy-paused migration state) or when the migration still
progresses between both QEMU processes, but libvirt lost control of it
because the connection between libvirt daemons (in p2p migration) or a
daemon and client (non-p2p migration) was closed. For example, when one
of the daemons was restarted.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
f1da6e9076 qemu: Do not set job owner in qemuMigrationJobSetPhase
Both qemuMigrationJobSetPhase and qemuMigrationJobStartPhase were doing
the same thing, which made little sense. Let's follow the difference
between qemuDomainObjSetJobPhase and qemuDomainObjStartJobPhase and
change job owner only in qemuMigrationJobStartPhase.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
2b163ca301 qemu: Refactor qemuDomainObjSetJobPhase
We will want to update migration phase without affecting job ownership.
Either in the thread that already owns the job or from an event handler
which only changes the phase (of a job no-one owns) without assuming it.

Let's move the ownership change to a new qemuDomainObjStartJobPhase
helper and let qemuDomainObjSetJobPhase set the phase without touching
ownership.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
69d9f54c66 qemu: Make qemuMigrationCheckPhase failure fatal
The check can reveal a serious bug in our migration code and we should
not silently ignore it.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
a5dc9bf96b qemu: Separate protocol checks from qemuMigrationJobSetPhase
Into a new qemuMigrationCheckPhase helper, which can be reused in other
places.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
6efd671a11 qemu: Add new migration phases for post-copy recovery
When recovering from a failed post-copy migration, we need to go through
all migration phases again, but don't need to repeat all the steps in
each phase. Let's create a new set of migration phases dedicated to
post-copy recovery so that we can easily distinguish between normal and
recovery code.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
ab3fd13932 qemu: Introduce qemuMigrationSrcBeginXML helper
Turn the final part of Begin phase formatting a domain XML for migration
into a reusable helper.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
3c1f37848d qemu: Check flags incompatible with offline migration earlier
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
2b137aba20 qemu: Improve post-copy migration handling on reconnect
When libvirt daemon is restarted during an active post-copy migration,
we do not always mark the migration as broken. In this phase libvirt is
not really needed for migration to finish successfully. In fact the
migration could have even finished while libvirt was not running or it
may still be happily running.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
c556d02551 qemu: Ignore missing memory statistics in query-migrate
We want to use query-migrate QMP command to check the current migration
state when reconnecting to active domains, but the reply we get to this
command may not contain any statistics at all if called on the
destination host.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
6908f857f8 qemu: Finish completed unattended migration
So far migration could only be completed while a migration API was
running and waiting for the migration to finish. In case such API could
not be called (the connection that initiated the migration is broken)
the migration would just be aborted or left in a "don't know what to do"
state. But this will change soon and we will be able to successfully
complete such migration once we get the corresponding event from QEMU.
This is specific to post-copy migration when vCPUs are already running
on the destination and we're only waiting for all memory pages to be
transferred. Such post-copy migration (which no-one is actively
watching) is called unattended migration.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
cc9f385a1d qemu: Pass qemuDomainJobObj to qemuMigrationDstComplete
When reconnecting to an active domain we need to use a different job
structure than the one referenced from the VM object.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
dbfcbe0896 qemu: Make sure migrationPort is released even in callbacks
Normally migrationPort is released in the Finish phase, but we need to
make sure it is properly released also in case qemuMigrationDstFinish is
not called at all. Currently the only callback which is called in this
situation qemuMigrationDstPrepareCleanup which already releases
migrationPort. This patch adds similar handling to additional callbacks
which will be used in the future.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
cff2e25043 qemu: Make final part of migration Confirm phase reusable
By separating it into a dedicated qemuMigrationSrcComplete function
which can be later called in other places.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
4c4e6913f4 qemu: Handle migration job in qemuMigrationDstFinish
The function which started a migration phase should also finish it by
calling qemuMigrationJobFinish/qemuMigrationJobContinue so that the code
is easier to follow.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
923ce7ed00 qemu: Introduce qemuMigrationDstFinishActive
Refactors qemuMigrationDstFinish by moving some parts to a dedicated
function for easier introduction of postcopy resume code without
duplicating common parts of the Finish phase. The goal is to have the
following call graph:

    - qemuMigrationDstFinish
        - qemuMigrationDstFinishOffline
        - qemuMigrationDstFinishActive
            - qemuMigrationDstFinishFresh
            - qemuMigrationDstFinishResume

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
229456b140 qemu: Separate cookie parsing for qemuMigrationDstFinishOffline
To keep all cookie handling (parsing and formatting) in the same
function.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
71951e9869 qemu: Introduce qemuMigrationDstFinishOffline
Refactors qemuMigrationDstFinish by moving some parts to a dedicated
function for easier introduction of postcopy resume code without
duplicating common parts of the Finish phase. The goal is to have the
following call graph:

    - qemuMigrationDstFinish
        - qemuMigrationDstFinishOffline
        - qemuMigrationDstFinishActive
            - qemuMigrationDstFinishFresh
            - qemuMigrationDstFinishResume

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
8ede853a9f qemu: Introduce qemuMigrationDstFinishFresh
Refactors qemuMigrationDstFinish by moving some parts to a dedicated
function for easier introduction of postcopy resume code without
duplicating common parts of the Finish phase. The goal is to have the
following call graph:

    - qemuMigrationDstFinish
        - qemuMigrationDstFinishOffline
        - qemuMigrationDstFinishActive
            - qemuMigrationDstFinishFresh
            - qemuMigrationDstFinishResume

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
3865596cf9 qemu: Preserve error in qemuMigrationDstFinish
We want to prevent our error path that can potentially kill the domain
on the destination host from overwriting an error reported earlier, but
we were only doing so in one specific path when starting vCPUs fails.
Let's do it in all paths.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
ea08483e7d qemu: Drop obsolete comment in qemuMigrationDstFinish
The comment about QEMU < 0.10.6 has been irrelevant for years.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
c41edf420b qemu: Make final part of migration Finish phase reusable
By separating it into a dedicated qemuMigrationDstComplete function
which can be later called in other places.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
c542432357 qemu: Generate migration cookie in Finish phase earlier
The final part of Finish phase will be refactored into a dedicated
function and we don't want to generate the cookie there.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
6bb40ef6b1 qemu: Rename "endjob" label in qemuMigrationDstFinish
Let's call it "error" so that it's clear the label is only used in
failure path.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
5eb956e284 qemu: Separate success and failure path in qemuMigrationDstFinish
Most of the code in "endjob" label is executed only on failure. Let's
duplicate the rest so that the label can be used only in error path
making the success path easier to follow and refactor.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
4cd9b5cdb8 qemu: Move success-only code out of endjob in qemuMigrationDstFinish
Code executed only when dom != NULL can be moved before "endjob" label,
to the only place where dom is set.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
b85eed31a5 qemu: Create domain object at the end of qemuMigrationDstFinish
We don't need the object until we get to the "endjob" label.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
73b81fc55f qemu: Add support for postcopy-recover QEMU migration state
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
5dd2d11ec0 qemu: Handle 'postcopy-paused' migration state
When connection breaks during post-copy migration, QEMU enters
'postcopy-paused' state. We need to handle this state and make the
situation visible to upper layers.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
458fa0e2bf qemu: Use switch in qemuProcessHandleMigrationStatus
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
425886ea99 qemu: Fetch paused migration stats
Even though a migration is paused, we still want to see the amount of
data transferred so far and that the migration is indeed not progressing
any further.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
918c14ee06 qemu: Don't wait for migration job when migration is running
Migration is a job which takes some time and if it succeeds, there's
nothing to call another migration on. If a migration fails, it might
make sense to rerun it with different arguments, but this would only be
done once the first migration fails rather than while it is still
running.

If this was not enough, the migration job now stays active even if
post-copy migration fails and anyone possibly retrying the migration
would be waiting for the job timeout just to get a suboptimal error
message.

So let's special case getting a migration job when another one is
already active.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
96db9dcfe9 qemu: Drop forward declarations in migration code
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
7c36e5004c qemu: Restore async job start timestamp on reconnect
Jobs that are supposed to remain active even when libvirt daemon
restarts were reported as started at the time the daemon was restarted.
This is not very helpful, we should restore the original timestamp.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
013d3091e0 qemu: Restore failed migration job on reconnect
Since we keep the migration job active when post-copy migration fails,
we need to restore it when reconnecting to running domains.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
c2f6a6a726 qemu: Abort failed post-copy when we haven't called Finish yet
When migration fails after it already switched to post-copy phase on the
source, but early enough that we haven't called Finish on the
destination yet, we know the vCPUs were not started on the destination
and the source host still has a complete state of the domain. Thus we
can just ignore the fact post-copy phase started and normally abort the
migration and resume vCPUs on the source.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
88a59fbbf3 qemu: Keep migration job active after failed post-copy
When post-copy migration fails, we can't just abort the migration and
resume the domain on the source host as it is already running on the
destination host and no host has a complete state of the domain memory.
Instead of the current approach of just marking the domain on both ends
as paused/running with a post-copy failed sub state, we will keep the
migration job active (even though the migration API will return failure)
so that the state is more visible and we can better control what APIs
can be called on the domains and even allow for resuming the migration.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
6637880b3c qemu: Add qemuDomainObjRestoreAsyncJob
The code for setting up a previously active backup job in
qemuProcessRecoverJob is generalized into a dedicated function so that
it can be later reused in other places.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
d6d1c4980d qemu: Rename qemuDomainObjRestoreJob as qemuDomainObjPreserveJob
It is used for saving job out of domain object. Just like
virErrorPreserveLast is used for errors. Let's make the naming
consistent as Restore would suggest different semantics.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
7c1840fa37 qemu: Introduce qemuProcessCleanupMigrationJob
The function can be used as a callback for qemuDomainCleanupAdd to
automatically clean up a migration job when a domain is destroyed.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
83ccd3a3d1 conf: Introduce virDomainObjIsPostcopy helper
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
efe95fb878 conf: Introduce virDomainObjIsFailedPostcopy helper
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
6ca0ff90ac qemu: Make qemuDomainCleanupAdd return void
The function never returns anything but zero.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00
Jiri Denemark
3abe9c496c qemu: Explicitly emit events on post-copy failure
The events would normally be triggered only if we're changing domain
state. But most of the time the domain is already in the right state and
we're just changing its substate from {PAUSED,RUNNING}_POSTCOPY to
*_POSTCOPY_FAILED. Let's emit lifecycle events explicitly when post-copy
migration fails to make the failure visible without polling.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2022-06-07 17:40:20 +02:00