Both migration thread or background snapshot thread will take a refcount of
the migration object at the entrace of the thread function.
That makes sense, because it protects the object from being freed by the
main thread in migration_shutdown() later, but it might still race with it
if the thread is scheduled too late. Consider the case right after
pthread_create() happened, VM shuts down with the object released, but
right after that the migration thread finally got created, referencing
MigrationState* in the opaque pointer which is already freed.
The only 100% safe way to make sure it won't get freed is taking the
refcount right before the thread is created, meanwhile when BQL is held.
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20241024213056.1395400-2-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
When VM is configured with huge memory, the current throttle logic
doesn't look like to scale, because migration_trigger_throttle()
is only called for each iteration, so it won't be invoked for a long
time if one iteration can take a long time.
The periodic dirty sync aims to fix the above issue by synchronizing
the ramblock from remote dirty bitmap and, when necessary, triggering
the CPU throttle multiple times during a long iteration.
This is a trade-off between synchronization overhead and CPU throttle
impact.
Signed-off-by: Hyman Huang <yong.huang@smartx.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/f61f1b3653f2acf026901103e1c73d157d38b08f.1729146786.git.yong.huang@smartx.com
[peterx: make prev_cnt global, and reset for each migration]
Signed-off-by: Peter Xu <peterx@redhat.com>
Move cpu-throttle.c from system to migration since it's
only used for migration; this makes us avoid exporting the
util functions and variables in misc.h but export them in
migration.h when implementing the periodic ramblock dirty
sync feature in the upcoming commits.
Since CPU throttle timers are only used in migration, move
their registry to migration_object_init.
Signed-off-by: Hyman Huang <yong.huang@smartx.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/c1b3efaa0cb49e03d422e9da97bdb65cc3d234d1.1729146786.git.yong.huang@smartx.com
[peterx: Fix build on MacOS on cocoa.m, not move cpu-throttle.h yet]
[peterx: Fix subject spelling, per pm215]
Signed-off-by: Peter Xu <peterx@redhat.com>
Keep migration thread names together, so it's easier to see a list of all
possible migration threads.
Still two functional changes below besides the macro defintions:
- There's one dirty rate thread that we overlooked before, now we add
that too and name it as "mig/dirtyrate" following the old rules.
- The old name "mig/src/rp-thr" has "-thr" but it may not be useful if
it's a thread name anyway, while "rp" can be slightly hard to read.
Taking this chance to rename it to "mig/src/return", hopefully a better
name.
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Acked-by: Hyman Huang <yong.huang@smartx.com>
Reviewed-by: Zhang Chen <chen.zhang@intel.com>
Link: https://lore.kernel.org/r/20241011153652.517440-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
The cleanup function can in many cases needs cleanup on its own.
The major thing we want to do here is not referencing to_dst_file when
without the file mutex. When at it, touch things elsewhere too to make it
look slightly better in general.
One thing to mention is, migration_thread has its own "running" boolean, so
it doesn't need to rely on to_dst_file being non-NULL. Multifd has a
dependency so it needs to be skipped if to_dst_file is not yet set; add a
richer comment for such reason.
Resolves: Coverity CID 1527402
Reported-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240919163042.116767-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
../migration/dirtyrate.c:186:5: error: ‘records’ may be used uninitialized [-Werror=maybe-uninitialized]
../migration/dirtyrate.c:168:12: error: ‘gen_id’ may be used uninitialized [-Werror=maybe-uninitialized]
../migration/migration.c:2273:5: error: ‘file’ may be used uninitialized [-Werror=maybe-uninitialized]
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Hyman Huang <yong.huang@smartx.com>
Fix a segmentation fault in multifd when rb->receivedmap is cleared
too early.
After commit 5ef7e26bdb ("migration/multifd: solve zero page causing
multiple page faults"), multifd started using the rb->receivedmap
bitmap, which belongs to ram.c and is initialized and *freed* from the
ram SaveVMHandlers.
Multifd threads are live until migration_incoming_state_destroy(),
which is called after qemu_loadvm_state_cleanup(), leading to a crash
when accessing rb->receivedmap.
process_incoming_migration_co() ...
qemu_loadvm_state() multifd_nocomp_recv()
qemu_loadvm_state_cleanup() ramblock_recv_bitmap_set_offset()
rb->receivedmap = NULL set_bit_atomic(..., rb->receivedmap)
...
migration_incoming_state_destroy()
multifd_recv_cleanup()
multifd_recv_terminate_threads(NULL)
Move the loadvm cleanup into migration_incoming_state_destroy(), after
multifd_recv_cleanup() to ensure multifd threads have already exited
when rb->receivedmap is cleared.
Adjust the postcopy listen thread comment to indicate that we still
want to skip the cpu synchronization.
CC: qemu-stable@nongnu.org
Fixes: 5ef7e26bdb ("migration/multifd: solve zero page causing multiple page faults")
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240917185802.15619-3-farosas@suse.de
[peterx: added comment in migration_incoming_state_destroy()]
Signed-off-by: Peter Xu <peterx@redhat.com>
This patch adds a migration state on src called "postcopy-recover-setup".
The new state will describe the intermediate step starting from when the
src QEMU received a postcopy recovery request, until the migration channels
are properly established, but before the recovery process take place.
The request came from Libvirt where Libvirt currently rely on the migration
state events to detect migration state changes. That works for most of the
migration process but except postcopy recovery failures at the beginning.
Currently postcopy recovery only has two major states:
- postcopy-paused: this is the state that both sides of QEMU will be in
for a long time as long as the migration channel was interrupted.
- postcopy-recover: this is the state where both sides of QEMU handshake
with each other, preparing for a continuation of postcopy which used to
be interrupted.
The issue here is when the recovery port is invalid, the src QEMU will take
the URI/channels, noticing the ports are not valid, and it'll silently keep
in the postcopy-paused state, with no event sent to Libvirt. In this case,
the only thing Libvirt can do is to poll the migration status with a proper
interval, however that's less optimal.
Considering that this is the only case where Libvirt won't get a
notification from QEMU on such events, let's add postcopy-recover-setup
state to mimic what we have with the "setup" state of a newly initialized
migration, describing the phase of connection establishment.
With that, postcopy recovery will have two paths to go now, and either path
will guarantee an event generated. Now the events will look like this
during a recovery process on src QEMU:
- Initially when the recovery is initiated on src, QEMU will go from
"postcopy-paused" -> "postcopy-recover-setup". Old QEMUs don't have
this event.
- Depending on whether the channel re-establishment is succeeded:
- In succeeded case, src QEMU will move from "postcopy-recover-setup"
to "postcopy-recover". Old QEMUs also have this event.
- In failure case, src QEMU will move from "postcopy-recover-setup" to
"postcopy-paused" again. Old QEMUs don't have this event.
This guarantees that Libvirt will always receive a notification for
recovery process properly.
One thing to mention is, such new status is only needed on src QEMU not
both. On dest QEMU, the state machine doesn't change. Hence the events
don't change either. It's done like so because dest QEMU may not have an
explicit point of setup start. E.g., it can happen that when dest QEMUs
doesn't use migrate-recover command to use a new URI/channel, but the old
URI/channels can be reused in recovery, in which case the old ports simply
can work again after the network routes are fixed up.
Add a new helper postcopy_is_paused() detecting whether postcopy is still
paused, taking RECOVER_SETUP into account too. When using it on both
src/dst, a slight change is done altogether to always wait for the
semaphore before checking the status, because for both sides a sem_post()
will be required for a recovery.
Cc: Jiri Denemark <jdenemar@redhat.com>
Cc: Prasad Pandit <ppandit@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Buglink: https://issues.redhat.com/browse/RHEL-38485
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Destination QEMU can setup incoming ports for two purposes: either a fresh
new incoming migration, in which QEMU will switch to SETUP for channel
establishment, or a paused postcopy migration, in which QEMU will stay in
POSTCOPY_PAUSED until kicking off the RECOVER phase.
Now the state machine worked on dest node for the latter, only because
migrate_set_state() implicitly will become a noop if the current state
check failed. It wasn't clear at all.
Clean it up by providing a helper migration_incoming_state_setup() doing
proper checks over current status. Postcopy-paused will be explicitly
checked now, and then we can bail out for unknown states.
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
QEMU uses "int" in most cases even if it stores MigrationStatus. I don't
know why, so let's try to do that right and see what blows up..
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
The postcopy thread names on dest QEMU are slightly confusing, partly I'll
need to blame myself on 36f62f11e4 ("migration: Postcopy preemption
preparation on channel creation"). E.g., "fault-fast" reads like a fast
version of "fault-default", but it's actually the fast version of
"postcopy/listen".
Taking this chance, rename all the migration threads with proper rules.
Considering we only have 15 chars usable, prefix all threads with "mig/",
meanwhile identify src/dst threads properly this time. So now most thread
names will look like "mig/DIR/xxx", where DIR will be "src"/"dst", except
the bg-snapshot thread which doesn't have a direction.
For multifd threads, making them "mig/{src|dst}/{send|recv}_%d".
We used to have "live_migration" thread for a very long time, now it's
called "mig/src/main". We may hope to have "mig/dst/main" soon but not
yet.
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Zhijian Li (Fujitsu) <lizhijian@fujitsu.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
When multifd is used along with mapped-ram, we can take benefit of a
filesystem that supports the O_DIRECT flag and perform direct I/O in
the multifd threads. This brings a significant performance improvement
because direct-io writes bypass the page cache which would otherwise
be thrashed by the multifd data which is unlikely to be needed again
in a short period of time.
To be able to use a multifd channel opened with O_DIRECT, we must
ensure that a certain aligment is used. Filesystems usually require a
block-size alignment for direct I/O. The way to achieve this is by
enabling the mapped-ram feature, which already aligns its I/O properly
(see MAPPED_RAM_FILE_OFFSET_ALIGNMENT at ram.c).
By setting O_DIRECT on the multifd channels, all writes to the same
file descriptor need to be aligned as well, even the ones that come
from outside multifd, such as the QEMUFile I/O from the main migration
code. This makes it impossible to use the same file descriptor for the
QEMUFile and for the multifd channels. The various flags and metadata
written by the main migration code will always be unaligned by virtue
of their small size. To workaround this issue, we'll require a second
file descriptor to be used exclusively for direct I/O.
The second file descriptor can be obtained by QEMU by re-opening the
migration file (already possible), or by being provided by the user or
management application (support to be added in future patches).
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
- Li Zhijian's COLO minor fixes
- Marc-André's virtio-gpu fix
- Fiona's virtio-net USO fix
- A couple of migration-test fixes from Thomas
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Merge tag 'migration-20240522-pull-request' of https://gitlab.com/farosas/qemu into staging
Migration pull request
- Li Zhijian's COLO minor fixes
- Marc-André's virtio-gpu fix
- Fiona's virtio-net USO fix
- A couple of migration-test fixes from Thomas
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# gpg: Signature made Wed 22 May 2024 03:13:28 PM PDT
# gpg: using RSA key AA1B48B0A22326A5A4C364CFC798DC741BEC319D
# gpg: issuer "farosas@suse.de"
# gpg: Good signature from "Fabiano Rosas <farosas@suse.de>" [unknown]
# gpg: aka "Fabiano Almeida Rosas <fabiano.rosas@suse.com>" [unknown]
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg: There is no indication that the signature belongs to the owner.
# Primary key fingerprint: AA1B 48B0 A223 26A5 A4C3 64CF C798 DC74 1BEC 319D
* tag 'migration-20240522-pull-request' of https://gitlab.com/farosas/qemu:
tests/qtest/migration-test: Fix the check for a successful run of analyze-migration.py
tests/qtest/migration-test: Run some basic tests on s390x and ppc64 with TCG, too
hw/core/machine: move compatibility flags for VirtIO-net USO to machine 8.1
virtio-gpu: fix v2 migration
migration: fix a typo
migration: add "exists" info to load-state-field trace
migration/colo: Tidy up bql_unlock() around bdrv_activate_all()
migration/colo: make colo_incoming_co() return void
migration/colo: Minor fix for colo error message
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Currently, it always returns 0, no need to check the return value at all.
In addition, enter colo coroutine only if migration_incoming_colo_enabled()
is true.
Once the destination side enters the COLO* state, the COLO process will
take over the remaining processes until COLO exits.
Cc: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Zhang Chen <chen.zhang@intel.com>
Signed-off-by: Li Zhijian <lizhijian@fujitsu.com>
[fixed mangled author email address]
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Use it to update the current error of the migration stream if
available and if not, simply print out the error. Next changes will
update with an error to report.
Reviewed-by: Avihai Horon <avihaih@nvidia.com>
Acked-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>
The 'compress' migration capability enables the old compression code
which has shown issues over the years and is thought to be less stable
and tested than the more recent multifd-based compression. The old
compression code has been deprecated in 8.2 and now is time to remove
it.
Deprecation commit 864128df46 ("migration: Deprecate old compression
method").
Acked-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
The block migration has been considered obsolete since QEMU 8.2 in
favor of the more flexible storage migration provided by the
blockdev-mirror driver. Two releases have passed so now it's time to
remove it.
Deprecation commit 66db46ca83 ("migration: Deprecate block
migration").
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
The block migration is considered obsolete and has been deprecated in
8.2. Remove the migrate command option that enables it. This only
affects the QMP and HMP commands, the feature can still be accessed by
setting the migration 'block' capability. The whole feature will be
removed in a future patch.
Deprecation commit 8846b5bfca ("migration: migrate 'blk' command
option is deprecated.").
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
The block incremental option for block migration has been deprecated
in 8.2 in favor of using the block-mirror feature. Remove it now.
Deprecation commit 40101f320d ("migration: migrate 'inc' command
option is deprecated.").
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
The 'skipped' field of the MigrationStats struct has been deprecated
in 8.1. Time to remove it.
Deprecation commit 7b24d32634 ("migration: skipped field is really
obsolete.").
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Now we do set MIGRATION_FAILED state, but don't give a chance to
orchestrator to query migration state and get the error.
Let's provide a possibility for QMP-based orchestrators to get an error
like with outgoing migration.
For hmp_migrate_incoming(), let's enable the new behavior: HMP is not
and ABI, it's mostly intended to use by developer and it makes sense
not to stop the process.
For x-exit-preconfig, let's keep the old behavior:
- it's called from init(), so here we want to keep current behavior by
default
- it does exit on error by itself as well
So, if we want to change the behavior of x-exit-preconfig, it should be
another patch.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Acked-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Unify error reporting in the function. This simplifies the following
commit, which will not-exit-on-error behavior variant to the function.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
It's bad idea to leave critical section with error object freed, but
s->error still set, this theoretically may lead to use-after-free
crash. Let's avoid it.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Make call to migration_incoming_state_destroy(), instead of doing only
partial of it.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Address the comment added in commit 4629ed1e98
("qerror: Finally unused, clean up"), from 2015:
/*
* These macros will go away, please don't use
* in new code, and do not add new ones!
*/
Mechanical transformation using sed, manually
removing the definition in include/qapi/qmp/qerror.h.
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240312141343.3168265-10-armbru@redhat.com>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
[Straightforward conflict with commit aeaafb1e59 (migration: export
migration_is_running) resolved]
This prepares ground for the changes coming next which add an Error**
argument to the .save_setup() handler. Callers of qemu_savevm_state_setup()
now handle the error and fail earlier setting the migration state from
MIGRATION_STATUS_SETUP to MIGRATION_STATUS_FAILED.
In qemu_savevm_state(), move the cleanup to preserve the error
reported by .save_setup() handlers.
Since the previous behavior was to ignore errors at this step of
migration, this change should be examined closely to check that
cleanups are still correctly done.
Signed-off-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/20240320064911.545001-7-clg@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
There are several places where postcopy_start() fails without setting
errp. This can cause a null pointer de-reference, as in case of error,
the caller of postcopy_start() copies/prints the error set in errp.
Fix it by setting errp in all of postcopy_start() error paths.
Cc: qemu-stable <qemu-stable@nongnu.org>
Fixes: 908927db28 ("migration: Update error description whenever migration fails")
Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/20240328140252.16756-3-avihaih@nvidia.com
Signed-off-by: Peter Xu <peterx@redhat.com>
After commit 9425ef3f99 ("migration: Use migrate_has_error() in
close_return_path_on_source()"), close_return_path_on_source() assumes
that migration error is set if an error occurs during migration.
This may not be true if migration errors in migration_completion(). For
example, if qemu_savevm_state_complete_precopy() errors, migration error
will not be set.
This in turn, will cause a migration hang bug, similar to the bug that
was fixed by commit 22b04245f0 ("migration: Join the return path
thread before releasing to_dst_file"), as shutdown() will not be issued
for the return-path channel.
Fix it by ensuring migration error is set in case of error in
migration_completion().
Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Fixes: 9425ef3f99 ("migration: Use migrate_has_error() in close_return_path_on_source()")
Acked-by: Cédric Le Goater <clg@redhat.com>
Link: https://lore.kernel.org/r/20240328140252.16756-2-avihaih@nvidia.com
Signed-off-by: Peter Xu <peterx@redhat.com>
With current code base I can observe extremely high sync count during
precopy, as long as one enables postcopy-ram=on before switchover to
postcopy.
To provide some context of when QEMU decides to do a full sync: it checks
must_precopy (which implies "data must be sent during precopy phase"), and
as long as it is lower than the threshold size we calculated (out of
bandwidth and expected downtime) QEMU will kick off the slow/exact sync.
However, when postcopy is enabled (even if still during precopy phase), RAM
only reports all pages as can_postcopy, and report must_precopy==0. Then
"must_precopy <= threshold_size" mostly always triggers and enforces a slow
sync for every call to migration_iteration_run() when postcopy is enabled
even if not used. That is insane.
It turns out it was a regress bug introduced in the previous refactoring in
8.0 as reported by Nina [1]:
(a) c8df4a7aef ("migration: Split save_live_pending() into state_pending_*")
Then a workaround patch is applied at the end of release (8.0-rc4) to fix it:
(b) 28ef5339c3 ("migration: fix ram_state_pending_exact()")
However that "workaround" was overlooked when during the cleanup in this
9.0 release in this commit..
(c) b0504edd40 ("migration: Drop unnecessary check in ram's pending_exact()")
Then the issue was re-exposed as reported by Nina [1].
The problem with (b) is that it only fixed the case for RAM, rather than
all the rest of iterators. Here a slow sync should only be required if all
dirty data (precopy+postcopy) is less than the threshold_size that QEMU
calculated. It is even debatable whether a sync is needed when switched to
postcopy. Currently ram_state_pending_exact() will be mostly noop if
switched to postcopy, and that logic seems to apply too for all the rest of
iterators, as sync dirty bitmap during a postcopy doesn't make much sense.
However let's leave such change for later, as we're in rc phase.
So rather than reusing commit (b), this patch provides the complete fix for
all iterators. When at it, cleanup a little bit on the lines around.
[1] https://gitlab.com/qemu-project/qemu/-/issues/1565
Reported-by: Nina Schoetterl-Glausch <nsg@linux.ibm.com>
Fixes: b0504edd40 ("migration: Drop unnecessary check in ram's pending_exact()")
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240320214453.584374-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
This reverts commit decdc76772 in full
and also the relevant migration-tests from
7a09f09283.
After the addition of the new QAPI-based migration address API in 8.2
we've been converting an "fd:" URI into a SocketAddress, missing the
fact that the "fd:" syntax could also be used for a plain file instead
of a socket. This is a problem because the SocketAddress is part of
the API, so we're effectively asking users to create a "socket"
channel to pass in a plain file.
The easiest way to fix this situation is to deprecate the usage of
both SocketAddress and "fd:" when used with a plain file for
migration. Since this has been possible since 8.2, we can wait until
9.1 to deprecate it.
For 9.0, however, we should avoid adding further support to migration
to a plain file using the old "fd:" syntax or the new SocketAddress
API, and instead require the usage of either the old-style "file:" URI
or the FileMigrationArgs::filename field of the new API with the
"/dev/fdset/NN" syntax, both of which are already supported.
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240319210941.1907-1-farosas@suse.de
Signed-off-by: Peter Xu <peterx@redhat.com>
When doing migration using the fd: URI, QEMU will fetch the file
descriptor passed in via the monitor at
fd_start_outgoing|incoming_migration(), which means the checks at
migration_channels_and_transport_compatible() happen too soon and we
don't know at that point whether the FD refers to a plain file or a
socket.
For this reason, we've been allowing a migration channel of type
SOCKET_ADDRESS_TYPE_FD to pass the initial verifications in scenarios
where the socket migration is not supported, such as with fd + multifd.
The commit decdc76772 ("migration/multifd: Add mapped-ram support to
fd: URI") was supposed to add a second check prior to starting
migration to make sure a socket fd is not passed instead of a file fd,
but failed to do so.
Add the missing verification and update the comment explaining this
situation which is currently incorrect.
Fixes: decdc76772 ("migration/multifd: Add mapped-ram support to fd: URI")
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/20240315032040.7974-2-farosas@suse.de
Signed-off-by: Peter Xu <peterx@redhat.com>
Delete the MigrationState parameter from migration_is_setup_or_active
and move it to the public API in misc.h.
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Link: https://lore.kernel.org/r/1710179338-294359-3-git-send-email-steven.sistare@oracle.com
Signed-off-by: Peter Xu <peterx@redhat.com>
If we receive a file descriptor that points to a regular file, there's
nothing stopping us from doing multifd migration with mapped-ram to
that file.
Enable the fd: URI to work with multifd + mapped-ram.
Note that the fds passed into multifd are duplicated because we want
to avoid cross-thread effects when doing cleanup (i.e. close(fd)). The
original fd doesn't need to be duplicated because monitor_get_fd()
transfers ownership to the caller.
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/20240229153017.2221-23-farosas@suse.de
Signed-off-by: Peter Xu <peterx@redhat.com>
The new mapped-ram stream format uses a file transport and puts ram
pages in the migration file at their respective offsets and can be
done in parallel by using the pwritev system call which takes iovecs
and an offset.
Add support to enabling the new format along with multifd to make use
of the threading and page handling already in place.
This requires multifd to stop sending headers and leaving the stream
format to the mapped-ram code. When it comes time to write the data, we
need to call a version of qio_channel_write that can take an offset.
Usage on HMP is:
(qemu) stop
(qemu) migrate_set_capability multifd on
(qemu) migrate_set_capability mapped-ram on
(qemu) migrate_set_parameter max-bandwidth 0
(qemu) migrate_set_parameter multifd-channels 8
(qemu) migrate file:migfile
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240229153017.2221-21-farosas@suse.de
Signed-off-by: Peter Xu <peterx@redhat.com>
On the receiving side we don't need to differentiate between main
channel and threads, so whichever channel is defined first gets to be
the main one. And since there are no packets, use the atomic channel
count to index into the params array.
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240229153017.2221-19-farosas@suse.de
Signed-off-by: Peter Xu <peterx@redhat.com>
The mapped-ram migration format needs a channel that supports seeking
to be able to write each page to an arbitrary offset in the migration
stream.
Reviewed-by: "Daniel P. Berrangé" <berrange@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240229153017.2221-9-farosas@suse.de
Signed-off-by: Peter Xu <peterx@redhat.com>
Add a new migration capability 'mapped-ram'.
The core of the feature is to ensure that RAM pages are mapped
directly to offsets in the resulting migration file instead of being
streamed at arbitrary points.
The reasons why we'd want such behavior are:
- The resulting file will have a bounded size, since pages which are
dirtied multiple times will always go to a fixed location in the
file, rather than constantly being added to a sequential
stream. This eliminates cases where a VM with, say, 1G of RAM can
result in a migration file that's 10s of GBs, provided that the
workload constantly redirties memory.
- It paves the way to implement O_DIRECT-enabled save/restore of the
migration stream as the pages are ensured to be written at aligned
offsets.
- It allows the usage of multifd so we can write RAM pages to the
migration file in parallel.
For now, enabling the capability has no effect. The next couple of
patches implement the core functionality.
Acked-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240229153017.2221-8-farosas@suse.de
Signed-off-by: Peter Xu <peterx@redhat.com>
close_return_path_on_source() retrieves the migration error from the
the QEMUFile '->to_dst_file' to know if a shutdown is required. This
shutdown is required to exit the return-path thread.
Avoid relying on '->to_dst_file' and use migrate_has_error() instead.
(using to_dst_file is a heuristic to infer whether
rp_state.from_dst_file might be stuck on a recvmsg(). Using a generic
method for detecting errors is more reliable. We also want to reduce
dependency on QEMUFile::last_error)
Suggested-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
[added some words about the motivation for this patch]
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240226203122.22894-3-farosas@suse.de
Signed-off-by: Peter Xu <peterx@redhat.com>
The return path thread might hang at a blocking system call. Before
joining the thread we might need to issue a shutdown() on the socket
file descriptor to release it. To determine whether the shutdown() is
necessary we look at the QEMUFile error.
Make sure we only clean up the QEMUFile after the return path has been
waited for.
This fixes a hang when qemu_savevm_state_setup() produced an error
that was detected by migration_detect_error(). That skips
migration_completion() so close_return_path_on_source() would get
stuck waiting for the RP thread to terminate.
Reported-by: Cédric Le Goater <clg@redhat.com>
Tested-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240226203122.22894-2-farosas@suse.de
Signed-off-by: Peter Xu <peterx@redhat.com>
The QMP command query_migrate might see incorrect throughput numbers
if it runs after we've set the migration completion status but before
migration_calculate_complete() has updated s->total_time and s->mbps.
The migration status would show COMPLETED, but the throughput value
would be the one from the last iteration and not the one from the
whole migration. This will usually be a larger value due to the time
period being smaller (one iteration).
Move migration_calculate_complete() earlier so that the status
MIGRATION_STATUS_COMPLETED is only emitted after the final counters
update. Keep everything under the BQL so the QMP thread sees the
updates as atomic.
Rename migration_calculate_complete to migration_completion_end to
reflect its new purpose of also updating s->state.
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240226143335.14282-1-farosas@suse.de
Signed-off-by: Peter Xu <peterx@redhat.com>
When migration for cpr is initiated, stop the vm and set state
RUN_STATE_FINISH_MIGRATE before ram is saved. This eliminates the
possibility of ram and device state being out of sync, and guarantees
that a guest in the suspended state remains suspended, because qmp_cont
rejects a cont command in the RUN_STATE_FINISH_MIGRATE state.
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/1708622920-68779-11-git-send-email-steven.sistare@oracle.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Check the status returned by migration notifiers for event type
MIG_EVENT_PRECOPY_SETUP, and report errors. None of the notifiers
return an error status at this time.
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/1708622920-68779-10-git-send-email-steven.sistare@oracle.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Move common code for the error path in migrate_fd_connect to a shared
fail label. No functional change.
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/1708622920-68779-9-git-send-email-steven.sistare@oracle.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Keep a separate list of migration notifiers for each migration mode.
Suggested-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/1708622920-68779-8-git-send-email-steven.sistare@oracle.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Define MigrationNotifyFunc to improve type safety and simplify migration
notifiers.
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/1708622920-68779-7-git-send-email-steven.sistare@oracle.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Passing MigrationState to notifiers is unsound because they could access
unstable migration state internals or even modify the state. Instead, pass
the minimal info needed in a new MigrationEvent struct, which could be
extended in the future if needed.
Suggested-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/1708622920-68779-5-git-send-email-steven.sistare@oracle.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Change all migration notifiers to type NotifierWithReturn, so notifiers
can return an error status in a future patch. For now, pass NULL for the
notifier error parameter, and do not check the return value.
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/1708622920-68779-4-git-send-email-steven.sistare@oracle.com
[peterx: dropped unexpected update to roms/seabios-hppa]
Signed-off-by: Peter Xu <peterx@redhat.com>
We currently have an unfavorable situation around multifd channels
creation and the migration thread execution.
We create the multifd channels with qio_channel_socket_connect_async
-> qio_task_run_in_thread, but only connect them at the
multifd_new_send_channel_async callback, called from
qio_task_complete, which is registered as a glib event.
So at multifd_send_setup() we create the channels, but they will only
be actually usable after the whole multifd_send_setup() calling stack
returns back to the main loop. Which means that the migration thread
is already up and running without any possibility for the multifd
channels to be ready on time.
We currently rely on the channels-ready semaphore blocking
multifd_send_sync_main() until channels start to come up and release
it. However there have been bugs recently found when a channel's
creation fails and multifd_send_cleanup() is allowed to run while
other channels are still being created.
Let's start to organize this situation by moving the
multifd_send_setup() call into the migration thread. That way we
unblock the main-loop to dispatch the completion callbacks and
actually have a chance of getting the multifd channels ready for when
the migration thread needs them.
The next patches will deal with the synchronization aspects.
Note that this takes multifd_send_setup() out of the BQL.
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240206215118.6171-5-farosas@suse.de
Signed-off-by: Peter Xu <peterx@redhat.com>
Hide the error handling inside multifd_send_setup to make it cleaner
for the next patch to move the function around.
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240206215118.6171-4-farosas@suse.de
Signed-off-by: Peter Xu <peterx@redhat.com>
The commit in the fixes line mistakenly modified the channels and
transport compatibility check logic so it now checks multi-channel
support only for socket transport type.
Thus, running multifd migration using a transport other than socket that
is incompatible with multi-channels (such as "exec") would lead to a
segmentation fault instead of an error message.
For example:
(qemu) migrate_set_capability multifd on
(qemu) migrate -d "exec:cat > /tmp/vm_state"
Segmentation fault (core dumped)
Fix it by checking multi-channel compatibility for all transport types.
Cc: qemu-stable <qemu-stable@nongnu.org>
Fixes: d95533e1cd ("migration: modify migration_channels_and_uri_compatible() for new QAPI syntax")
Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/20240125162528.7552-2-avihaih@nvidia.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Most of the multifd code uses send/recv to represent the two sides, but
some rare cases use save/load.
Since send/recv is the majority, replacing the save/load use cases to use
send/recv globally. Now we reach a consensus on the naming.
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240202102857.110210-22-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
A memory page poisoned from the hypervisor level is no longer readable.
The migration of a VM will crash Qemu when it tries to read the
memory address space and stumbles on the poisoned page with a similar
stack trace:
Program terminated with signal SIGBUS, Bus error.
#0 _mm256_loadu_si256
#1 buffer_zero_avx2
#2 select_accel_fn
#3 buffer_is_zero
#4 save_zero_page
#5 ram_save_target_page_legacy
#6 ram_save_host_page
#7 ram_find_and_save_block
#8 ram_save_iterate
#9 qemu_savevm_state_iterate
#10 migration_iteration_run
#11 migration_thread
#12 qemu_thread_start
To avoid this VM crash during the migration, prevent the migration
when a known hardware poison exists on the VM.
Signed-off-by: William Roche <william.roche@oracle.com>
Link: https://lore.kernel.org/r/20240130190640.139364-2-william.roche@oracle.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Now that the migration state reference counting is correct, further
wrap the bottom half dispatch process to avoid future issues.
Move BH creation and scheduling together and wrap the dispatch with an
intermediary function that will ensure we always keep the ref/unref
balanced.
Also move the responsibility of deleting the BH into the wrapper and
remove the now unnecessary pointers.
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240119233922.32588-6-farosas@suse.de
Signed-off-by: Peter Xu <peterx@redhat.com>
We need to hold a reference to the current_migration object around
async calls to avoid it been freed while still in use.
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240119233922.32588-3-farosas@suse.de
Signed-off-by: Peter Xu <peterx@redhat.com>
We're currently allowing the process_incoming_migration_bh bottom-half
to run without holding a reference to the 'current_migration' object,
which leads to a segmentation fault if the BH is still live after
migration_shutdown() has dropped the last reference to
current_migration.
In my system the bug manifests as migrate_multifd() returning true
when it shouldn't and multifd_load_shutdown() calling
multifd_recv_terminate_threads() which crashes due to an uninitialized
multifd_recv_state.
Fix the issue by holding a reference to the object when scheduling the
BH and dropping it before returning from the BH. The same is already
done for the cleanup_bh at migrate_fd_cleanup_schedule().
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1969
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240119233922.32588-2-farosas@suse.de
Signed-off-by: Peter Xu <peterx@redhat.com>
We're not currently reporting the errors set with migrate_set_error()
when incoming migration fails.
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/20240104142144.9680-5-farosas@suse.de
Signed-off-by: Peter Xu <peterx@redhat.com>
The inital conditional statements in qmp migration functions is harder
to understand than necessary. It is better to get all errors out of
the way in the beginning itself to have better readability and error
handling.
Signed-off-by: Het Gala <het.gala@nutanix.com>
Suggested-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20231205080039.197615-1-het.gala@nutanix.com
Signed-off-by: Peter Xu <peterx@redhat.com>
The term "iothread lock" is obsolete. The APIs use Big QEMU Lock (BQL)
in their names. Update the code comments to use "BQL" instead of
"iothread lock".
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Paul Durrant <paul@xen.org>
Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Message-id: 20240102153529.486531-5-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The Big QEMU Lock (BQL) has many names and they are confusing. The
actual QemuMutex variable is called qemu_global_mutex but it's commonly
referred to as the BQL in discussions and some code comments. The
locking APIs, however, are called qemu_mutex_lock_iothread() and
qemu_mutex_unlock_iothread().
The "iothread" name is historic and comes from when the main thread was
split into into KVM vcpu threads and the "iothread" (now called the main
loop thread). I have contributed to the confusion myself by introducing
a separate --object iothread, a separate concept unrelated to the BQL.
The "iothread" name is no longer appropriate for the BQL. Rename the
locking APIs to:
- void bql_lock(void)
- void bql_unlock(void)
- bool bql_locked(void)
There are more APIs with "iothread" in their names. Subsequent patches
will rename them. There are also comments and documentation that will be
updated in later patches.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paul Durrant <paul@xen.org>
Acked-by: Fabiano Rosas <farosas@suse.de>
Acked-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Acked-by: Peter Xu <peterx@redhat.com>
Acked-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Acked-by: Hyman Huang <yong.huang@smartx.com>
Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-id: 20240102153529.486531-2-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
According to Error API, usage of ERRP_GUARD() or a local Error instead
of errp is needed if errp is passed to void functions, where it is later
dereferenced to see if an error occurred.
There are several places in migration.c that use local Error although it
is not needed. Change these places to use errp directly.
Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20231231093016.14204-11-avihaih@nvidia.com
Signed-off-by: Peter Xu <peterx@redhat.com>
If multifd_load_setup() fails in migration_ioc_process_incoming(),
error_setg() is called with errp. This will lead to an assert because in
that case errp already contains an error.
Fix it by removing the redundant error_setg().
Fixes: 6720c2b327 ("migration: check magic value for deciding the mapping of channels")
Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20231231093016.14204-9-avihaih@nvidia.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Commit 6720c2b327 ("migration: check magic value for deciding the
mapping of channels") extracted the only code that could fail in
migration_incoming_setup().
Now migration_incoming_setup() can't fail, so refactor it to return void
and remove errp parameter.
Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Link: https://lore.kernel.org/r/20231231093016.14204-4-avihaih@nvidia.com
Signed-off-by: Peter Xu <peterx@redhat.com>
MigrationState->hostname is set to NULL in migrate_init(). This is
redundant because it is already freed and set to NULL in
migrade_fd_cleanup(). Remove it.
Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20231231093016.14204-3-avihaih@nvidia.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Do not wake a suspended guest during bg_migration, and restore the prior
state at finish rather than unconditionally running. Allow the additional
state transitions that occur.
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/1704312341-66640-9-git-send-email-steven.sistare@oracle.com
Signed-off-by: Peter Xu <peterx@redhat.com>
A guest that is migrated in the suspended state automaticaly wakes and
continues execution. This is wrong; the guest should end migration in
the same state it started. The root cause is that the outgoing migration
code automatically wakes the guest, then saves the RUNNING runstate in
global_state_store(), hence the incoming migration code thinks the guest is
running and continues the guest if autostart is true.
On the outgoing side, delete the call to qemu_system_wakeup_request().
Now that vm_stop completely stops a vm in the suspended state (from the
preceding patches), the existing call to vm_stop_force_state is sufficient
to correctly migrate all vmstate.
On the incoming side, call vm_start if the pre-migration state was running
or suspended. For the latter, vm_start correctly restores the suspended
state, and a future system_wakeup monitor request will cause the vm to
resume running.
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/1704312341-66640-7-git-send-email-steven.sistare@oracle.com
Signed-off-by: Peter Xu <peterx@redhat.com>
migrate_uri_parse() allocates memory to 'channel' if the user
opts for old syntax - uri, which is leaked because there is no
code for freeing 'channel'.
So, free channel to avoid memory leak in case where 'channels'
is empty and uri parsing is required.
Fixes: 5994024f ("migration: Implement MigrateChannelList to qmp migration flow")
Signed-off-by: Het Gala <het.gala@nutanix.com>
Suggested-by: Markus Armbruster <armbru@redhat.com>
Tested-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Link: https://lore.kernel.org/r/20231129204301.131228-1-het.gala@nutanix.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Since socket_parse() will allocate memory for 'saddr',and its value
will pass to 'addr' that allocated by migrate_uri_parse(),
then 'saddr' will no longer used,need to free.
But due to 'saddr->u' is shallow copying the contents of the union,
the members of this union containing allocated strings,and will be used after that.
So just free 'saddr' itself without doing a deep free on the contents of the SocketAddress.
Fixes: 72a8192e22 ("migration: convert migration 'uri' into 'MigrateAddress'")
Signed-off-by: Zongmin Zhou<zhouzongmin@kylinos.cn>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231120031428.908295-1-zhouzongmin@kylinos.cn>
Integrate MigrateChannelList with all transport backends
(socket, exec and rdma) for both src and dest migration
endpoints for hmp migration.
Suggested-by: Aravind Retnakaran <aravind.retnakaran@nutanix.com>
Signed-off-by: Het Gala <het.gala@nutanix.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Message-ID: <20231023182053.8711-14-farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Integrate MigrateChannelList with all transport backends
(socket, exec and rdma) for both src and dest migration
endpoints for qmp migration.
For current series, limit the size of MigrateChannelList
to single element (single interface) as runtime check.
Suggested-by: Aravind Retnakaran <aravind.retnakaran@nutanix.com>
Signed-off-by: Het Gala <het.gala@nutanix.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231023182053.8711-13-farosas@suse.de>
migration_channels_and_uri_compatible() check for transport mechanism
suitable for multifd migration gets executed when the caller calls old
uri syntax. It needs it to be run when using the modern MigrateChannel
QAPI syntax too.
After URI -> 'MigrateChannel' :
migration_channels_and_uri_compatible() ->
migration_channels_and_transport_compatible() passes object as argument
and check for valid transport mechanism.
Suggested-by: Aravind Retnakaran <aravind.retnakaran@nutanix.com>
Signed-off-by: Het Gala <het.gala@nutanix.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231023182053.8711-12-farosas@suse.de>
MigrateChannelList allows to connect accross multiple interfaces.
Add MigrateChannelList struct as argument to migration QAPIs.
We plan to include multiple channels in future, to connnect
multiple interfaces. Hence, we choose 'MigrateChannelList'
as the new argument over 'MigrateChannel' to make migration
QAPIs future proof.
Suggested-by: Aravind Retnakaran <aravind.retnakaran@nutanix.com>
Signed-off-by: Het Gala <het.gala@nutanix.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231023182053.8711-10-farosas@suse.de>
Convert the file: URI to accept a FileMigrationArgs to be compatible
with the new migration QAPI.
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231023182053.8711-9-farosas@suse.de>
Exec transport backend for 'migrate'/'migrate-incoming' QAPIs accept
new wire protocol of MigrateAddress struct.
It is achived by parsing 'uri' string and storing migration parameters
required for exec connection into strList struct.
Suggested-by: Aravind Retnakaran <aravind.retnakaran@nutanix.com>
Signed-off-by: Het Gala <het.gala@nutanix.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231023182053.8711-8-farosas@suse.de>
RDMA based transport backend for 'migrate'/'migrate-incoming' QAPIs
accept new wire protocol of MigrateAddress struct.
It is achived by parsing 'uri' string and storing migration parameters
required for RDMA connection into well defined InetSocketAddress struct.
Suggested-by: Aravind Retnakaran <aravind.retnakaran@nutanix.com>
Signed-off-by: Het Gala <het.gala@nutanix.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231023182053.8711-7-farosas@suse.de>
Socket transport backend for 'migrate'/'migrate-incoming' QAPIs accept
new wire protocol of MigrateAddress struct.
It is achived by parsing 'uri' string and storing migration parameters
required for socket connection into well defined SocketAddress struct.
Suggested-by: Aravind Retnakaran <aravind.retnakaran@nutanix.com>
Signed-off-by: Het Gala <het.gala@nutanix.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231023182053.8711-6-farosas@suse.de>
This patch parses 'migrate' and 'migrate-incoming' QAPI's 'uri'
string containing migration connection related information
and stores them inside well defined 'MigrateAddress' struct.
Fabiano fixed for "file" transport.
Suggested-by: Aravind Retnakaran <aravind.retnakaran@nutanix.com>
Signed-off-by: Het Gala <het.gala@nutanix.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231023182053.8711-4-farosas@suse.de>
Message-ID: <20231023182053.8711-5-farosas@suse.de>
Now we have a Error** passed into the return path thread stack, which is
even clearer than an int retval. Change ram_dirty_bitmap_reload() and the
callers to use a bool instead to replace errnos.
Suggested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231017202633.296756-5-peterx@redhat.com>
Normally the postcopy recover phase should only exist for a super short
period, that's the duration when QEMU is trying to recover from an
interrupted postcopy migration, during which handshake will be carried out
for continuing the procedure with state changes from PAUSED -> RECOVER ->
POSTCOPY_ACTIVE again.
Here RECOVER phase should be super small, that happens right after the
admin specified a new but working network link for QEMU to reconnect to
dest QEMU.
However there can still be case where the channel is broken in this small
RECOVER window.
If it happens, with current code there's no way the src QEMU can got kicked
out of RECOVER stage. No way either to retry the recover in another channel
when established.
This patch allows the RECOVER phase to fail itself too - we're mostly
ready, just some small things missing, e.g. properly kick the main
migration thread out when sleeping on rp_sem when we found that we're at
RECOVER stage. When this happens, it fails the RECOVER itself, and
rollback to PAUSED stage. Then the user can retry another round of
recovery.
To make it even stronger, teach QMP command migrate-pause to explicitly
kick src/dst QEMU out when needed, so even if for some reason the migration
thread didn't got kicked out already by a failing rethrn-path thread, the
admin can also kick it out.
This will be an super, super corner case, but still try to cover that.
One can try to test this with two proxy channels for migration:
(a) socat unix-listen:/tmp/src.sock,reuseaddr,fork tcp:localhost:10000
(b) socat tcp-listen:10000,reuseaddr,fork unix:/tmp/dst.sock
So the migration channel will be:
(a) (b)
src -> /tmp/src.sock -> tcp:10000 -> /tmp/dst.sock -> dst
Then to make QEMU hang at RECOVER stage, one can do below:
(1) stop the postcopy using QMP command postcopy-pause
(2) kill the 2nd proxy (b)
(3) try to recover the postcopy using /tmp/src.sock on src
(4) src QEMU will go into RECOVER stage but won't be able to continue
from there, because the channel is actually broken at (b)
Before this patch, step (4) will make src QEMU stuck in RECOVER stage,
without a way to kick the QEMU out or continue the postcopy again. After
this patch, (4) will quickly fail qemu and bounce back to PAUSED stage.
Admin can also kick QEMU from (4) into PAUSED when needed using
migrate-pause when needed.
After bouncing back to PAUSED stage, one can recover again.
Reported-by: Xiaohui Li <xiaohli@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2111332
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231017202633.296756-3-peterx@redhat.com>
rp_state.error was a boolean used to show error happened in return path
thread. That's not only duplicating error reporting (migrate_set_error),
but also not good enough in that we only do error_report() and set it to
true, we never can keep a history of the exact error and show it in
query-migrate.
To make this better, a few things done:
- Use error_setg() rather than error_report() across the whole lifecycle
of return path thread, keeping the error in an Error*.
- With above, no need to have mark_source_rp_bad(), remove it, alongside
with rp_state.error itself.
- Use migrate_set_error() to apply that captured error to the global
migration object when error occured in this thread.
- Do the same when detected qemufile error in source return path
We need to re-export qemu_file_get_error_obj() to do the last one.
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231017202633.296756-2-peterx@redhat.com>
Extend the blocker interface so that a blocker can be registered for
one or more migration modes. The existing interfaces register a
blocker for all modes, and the new interfaces take a varargs list
of modes.
Internally, maintain a separate blocker list per mode. The same Error
object may be added to multiple lists. When a block is deleted, it is
removed from every list, and the Error is freed.
No functional change until a new mode is added.
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <1698263069-406971-3-git-send-email-steven.sistare@oracle.com>
This patch is inspired by Joao Martin's patch here:
https://lore.kernel.org/r/20230926161841.98464-1-joao.m.martins@oracle.com
Add tracepoints for major downtime checkpoints on both src and dst. They
share the same tracepoint with a string showing its stage.
Besides the checkpoints in the previous patch, this patch also added
destination checkpoints.
On src, we have these checkpoints added:
- src-downtime-start: right before vm stops on src
- src-vm-stopped: after vm is fully stopped
- src-iterable-saved: after all iterables saved (END sections)
- src-non-iterable-saved: after all non-iterable saved (FULL sections)
- src-downtime-stop: migration fully completed
On dst, we have these checkpoints added:
- dst-precopy-loadvm-completes: after loadvm all done for precopy
- dst-precopy-bh-*: record BH steps to resume VM for precopy
- dst-postcopy-bh-*: record BH steps to resume VM for postcopy
On dst side, we don't have a good way to trace total time consumed by
iterable or non-iterable for now. We can mark it by 1st time receiving a
FULL / END section, but rather than that let's just rely on the other
tracepoints added for vmstates to back up the information.
With this patch, one can enable "vmstate_downtime*" tracepoints and it'll
enable all tracepoints for downtime measurements necessary.
Drop loadvm_postcopy_handle_run_bh() tracepoint alongside, because they
service the same purpose, which was only for postcopy. We then have
unified prefix for all downtime relevant tracepoints.
Co-developed-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231030163346.765724-6-peterx@redhat.com>
Provide a helper for non-COLO use case of migration to stop a VM. This
prepares for adding some downtime relevant tracepoints to migration, where
they may or may not apply to COLO.
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231030163346.765724-5-peterx@redhat.com>
Unify the three users on recording downtimes with the same pair of helpers.
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231030163346.765724-3-peterx@redhat.com>
Postcopy calculates its downtime separately. It always sets
MigrationState.downtime properly, but not MigrationState.downtime_start.
Make postcopy do the same as other modes on properly recording the
timestamp when the VM is going to be stopped. Drop the temporary variable
in postcopy_start() along the way.
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231030163346.765724-2-peterx@redhat.com>
This let us simplify code of this shape.
qemu_fflush(f);
int ret = qemu_file_get_error(f);
if (ret) {
return ret;
}
into:
int ret = qemu_fflush(f);
if (ret) {
return ret;
}
I updated all callers where there is any error check.
qemu_fclose() don't need to check for f->last_error because
qemu_fflush() returns it at the beggining of the function.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231025091117.6342-13-quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
