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2024-08-16savevm: Fix load_snapshot error path crashNicholas Piggin1-0/+1
An error path missed setting *errp, which can cause a NULL deref. Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Message-Id: <20240813050638.446172-11-npiggin@gmail.com> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Message-Id: <20240813202329.1237572-19-alex.bennee@linaro.org>
2024-08-02migration: Free removed SaveStateEntryAkihiko Odaki1-0/+2
This fixes LeakSanitizer warnings. Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Fabiano Rosas <farosas@suse.de>
2024-06-21migration/postcopy: Add postcopy-recover-setup phasePeter Xu1-2/+2
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>
2024-06-21migration: Rename thread debug namesPeter Xu1-1/+1
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>
2024-05-27migration: Rephrase message on failure to save / load Xen device stateMarkus Armbruster1-3/+2
Functions that use an Error **errp parameter to return errors should not also report them to the user, because reporting is the caller's job. When the caller does, the error is reported twice. When it doesn't (because it recovered from the error), there is no error to report, i.e. the report is bogus. qmp_xen_save_devices_state() and qmp_xen_load_devices_state() violate this principle: they call qemu_save_device_state() and qemu_loadvm_state(), which call error_report_err(). I wish I could clean this up now, but migration's error reporting is too complicated (confused?) for me to mess with it. Instead, I'm merely improving the error reported by qmp_xen_load_devices_state() and qmp_xen_load_devices_state() to the QMP core from An IO error has occurred to saving Xen device state failed and loading Xen device state failed respectively. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-ID: <20240513141703.549874-6-armbru@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Acked-by: Fabiano Rosas <farosas@suse.de> Acked-by: Peter Xu <peterx@redhat.com>
2024-05-08migration: Remove block migrationFabiano Rosas1-5/+0
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>
2024-04-24Merge tag 'pull-error-2024-04-24' of https://repo.or.cz/qemu/armbru into stagingRichard Henderson1-1/+1
Error reporting patches for 2024-04-24 # -----BEGIN PGP SIGNATURE----- # # iQJGBAABCAAwFiEENUvIs9frKmtoZ05fOHC0AOuRhlMFAmYouloSHGFybWJydUBy # ZWRoYXQuY29tAAoJEDhwtADrkYZTzLwP+wQjCWJHpTB+uQ3+U5Tb77BUJxuEjDMj # txNIJBXHOo7erxTSCieLuQICm8e30z62QAK4nVStyMDcyGh1KfwdSDAxBFnuLpA2 # 7X5bXbvCrm4vXVASRTV1zKCYDlIXFfrMWLvN5KgM90RsodLcy0szlXg+qYyoIM3Z # 8zp0Ug0fQPFHiOAQJi9ZTOsCYJBhZc2sbzgQEmf/g6q9bJaZHzPEHvVT4AQhTAtn # 7BIJY+vGDZNZwbP/0obWy2lai3kbGak8OXpwq/bewdrxeRmvqmM7sk+V/P2tXQD+ # kZe0/HWuDoO5J8L3KHiJnBJ0KCk8fbo4I0T6v9vf55Sj8K0r7O9sykgXXWv8q0lO # GrQa0YcyWAckI41stYQpwEpIlRanuZv/p8OZFJIqsTAfaw7RlbIBYA9xZCUnTton # FbHO/t2BLfo8eO9/xRD4r1u6vMbVozImPETuUMPyLHzlrdw2thxddKQNInHYYZ2U # SvvaByceEP2UywOnOflZhVL2dIhhnrBztiW2Vqod1fQHpfBAcJn909PZIlPZyMkr # gUnABI/rtC/lW3pBee6HmfzJ6Fah0e0XCpCY20qFe27Bi/z3xKi5NWYuyAUG5csp # CuTsc4pXfPVj5Z+Mk4pyY8PK5k4jSa7vAVLCLTNzXJLZlJTb6yuf0HsJ7768nHDc # hSEIjLwQWYtw # =r8Rv # -----END PGP SIGNATURE----- # gpg: Signature made Wed 24 Apr 2024 12:52:58 AM PDT # gpg: using RSA key 354BC8B3D7EB2A6B68674E5F3870B400EB918653 # gpg: issuer "armbru@redhat.com" # gpg: Good signature from "Markus Armbruster <armbru@redhat.com>" [undefined] # gpg: aka "Markus Armbruster <armbru@pond.sub.org>" [undefined] # 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: 354B C8B3 D7EB 2A6B 6867 4E5F 3870 B400 EB91 8653 * tag 'pull-error-2024-04-24' of https://repo.or.cz/qemu/armbru: qapi: Inline and remove QERR_PROPERTY_VALUE_BAD definition qapi: Inline and remove QERR_MIGRATION_ACTIVE definition qapi: Correct error message for 'vcpu_dirty_limit' parameter qapi: Inline and remove QERR_INVALID_PARAMETER_TYPE definition qapi: Inline QERR_INVALID_PARAMETER_TYPE definition (constant value) qapi: Inline and remove QERR_INVALID_PARAMETER definition qapi: Inline and remove QERR_DEVICE_NO_HOTPLUG definition qapi: Inline and remove QERR_DEVICE_HAS_NO_MEDIUM definition qapi: Inline and remove QERR_BUS_NO_HOTPLUG definition error: Drop superfluous #include "qapi/qmp/qerror.h" Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2024-04-24qapi: Inline and remove QERR_MIGRATION_ACTIVE definitionPhilippe Mathieu-Daudé1-1/+1
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 aeaafb1e59f (migration: export migration_is_running) resolved]
2024-04-23migration: Add Error** argument to .load_setup() handlerCédric Le Goater1-4/+7
This will be useful to report errors at a higher level, mostly in VFIO today. Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Cédric Le Goater <clg@redhat.com> Link: https://lore.kernel.org/r/20240320064911.545001-9-clg@redhat.com [peterx: drop comment for ERRP_GUARD, per Markus] Signed-off-by: Peter Xu <peterx@redhat.com>
2024-04-23migration: Add Error** argument to .save_setup() handlerCédric Le Goater1-3/+1
The purpose is to record a potential error in the migration stream if qemu_savevm_state_setup() fails. Most of the current .save_setup() handlers can be modified to use the Error argument instead of managing their own and calling locally error_report(). Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Harsh Prateek Bora <harshpb@linux.ibm.com> Cc: Halil Pasic <pasic@linux.ibm.com> Cc: Thomas Huth <thuth@redhat.com> Cc: Eric Blake <eblake@redhat.com> Cc: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Cc: John Snow <jsnow@redhat.com> Cc: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Peter Xu <peterx@redhat.com> Reviewed-by: Thomas Huth <thuth@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Signed-off-by: Cédric Le Goater <clg@redhat.com> Link: https://lore.kernel.org/r/20240320064911.545001-8-clg@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com>
2024-04-23migration: Add Error** argument to qemu_savevm_state_setup()Cédric Le Goater1-11/+15
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>
2024-04-23migration: Add Error** argument to vmstate_save()Cédric Le Goater1-10/+16
This will prepare ground for future changes adding an Error** argument to qemu_savevm_state_setup(). Reviewed-by: Prasad Pandit <pjp@fedoraproject.org> Signed-off-by: Cédric Le Goater <clg@redhat.com> Link: https://lore.kernel.org/r/20240320064911.545001-6-clg@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com>
2024-04-07migration/postcopy: ensure preempt channel is ready before loading statesWei Wang1-0/+21
Before loading the guest states, ensure that the preempt channel has been ready to use, as some of the states (e.g. via virtio_load) might trigger page faults that will be handled through the preempt channel. So yield to the main thread in the case that the channel create event hasn't been dispatched. Cc: qemu-stable <qemu-stable@nongnu.org> Fixes: 9358982744 ("migration: Send requested page directly in rp-return thread") Originally-by: Lei Wang <lei4.wang@intel.com> Link: https://lore.kernel.org/all/9aa5d1be-7801-40dd-83fd-f7e041ced249@intel.com/T/ Signed-off-by: Lei Wang <lei4.wang@intel.com> Signed-off-by: Wei Wang <wei.w.wang@intel.com> Link: https://lore.kernel.org/r/20240405034056.23933-1-wei.w.wang@intel.com [peterx: add a todo section, add Fixes and copy stable for 8.0+] Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-11migration: export migration_is_runningSteve Sistare1-1/+1
Delete the MigrationState parameter from migration_is_running and move it to the public API in misc.h. Signed-off-by: Steve Sistare <steven.sistare@oracle.com> Link: https://lore.kernel.org/r/1710179338-294359-5-git-send-email-steven.sistare@oracle.com Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-11migration: Do not call PRECOPY_NOTIFY_SETUP notifiers in case of errorCédric Le Goater1-1/+5
When commit bd2270608fa0 ("migration/ram.c: add a notifier chain for precopy") added PRECOPY_NOTIFY_SETUP notifiers at the end of qemu_savevm_state_setup(), it didn't take into account a possible error in the loop calling vmstate_save() or .save_setup() handlers. Check ret value before calling the notifiers. Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Cédric Le Goater <clg@redhat.com> Link: https://lore.kernel.org/r/20240304122844.1888308-10-clg@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-11migration: Don't serialize devices in qemu_savevm_state_iterate()Avihai Horon1-9/+6
Commit 90697be8896c ("live migration: Serialize vmstate saving in stage 2") introduced device serialization in qemu_savevm_state_iterate(). The rationale behind it was to first complete migration of slower changing block devices and only then migrate the RAM, to avoid sending fast changing RAM pages over and over. This commit was added a long time ago, and while it was useful back then, it is not the case anymore: 1. Block migration is deprecated, see commit 66db46ca83b8 ("migration: Deprecate block migration"). 2. Today there are other iterative devices besides RAM and block, such as VFIO, which are registered for migration after RAM. With current serialization behavior, a fast changing device can block other devices from sending their data, which may prevent migration from converging in some cases. The issue described in item 2 was observed in several VFIO migration scenarios with switchover-ack capability enabled, where some workload on the VM prevented RAM from ever reaching a hard zero, thus blocking VFIO initial pre-copy data from being sent. Hence, destination could not ack switchover and migration could not converge. Fix that by not serializing iterative devices in qemu_savevm_state_iterate(). Note that this still doesn't fully prevent device starvation. As correctly pointed out by Peter [1], a fast changing device might constantly consume all allocated bandwidth and block the following devices. However, this scenario is more likely to happen only if max-bandwidth is low. [1] https://lore.kernel.org/qemu-devel/Zd6iw9dBhW6wKNxx@x1n/ Signed-off-by: Avihai Horon <avihaih@nvidia.com> Reviewed-by: Fabiano Rosas <farosas@suse.de> Link: https://lore.kernel.org/r/20240304105339.20713-2-avihaih@nvidia.com Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-01migration/ram: Introduce 'mapped-ram' migration capabilityFabiano Rosas1-0/+1
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>
2024-01-29migration: Centralize BH creation and dispatchFabiano Rosas1-6/+1
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>
2024-01-29migration: Reference migration state around loadvm_postcopy_handle_run_bhFabiano Rosas1-0/+2
We need to hold a reference to the current_migration object around async calls to avoid it been freed while still in use. Even on this load-side function, we might still use the MigrationState, e.g to check for capabilities. Signed-off-by: Fabiano Rosas <farosas@suse.de> Link: https://lore.kernel.org/r/20240119233922.32588-4-farosas@suse.de Signed-off-by: Peter Xu <peterx@redhat.com>
2024-01-05Merge tag 'migration-20240104-pull-request' of ↵Peter Maydell1-10/+13
https://gitlab.com/peterx/qemu into staging migration 1st pull for 9.0 - We lost Juan and Leo in the maintainers file - Steven's suspend state fix - Steven's fix for coverity on migrate_mode - Avihai's migration cleanup series # -----BEGIN PGP SIGNATURE----- # # iIgEABYKADAWIQS5GE3CDMRX2s990ak7X8zN86vXBgUCZZY0TxIccGV0ZXJ4QHJl # ZGhhdC5jb20ACgkQO1/MzfOr1wbSxgEAoM5g3wkc22lpAlRpU+hJUqT9NVOVQSK+ # Fk7XJYTdSgABAKzykA6hAmU5Kj+yVI6jI874SVZbs2FWpFs4osvsKk4D # =sfuM # -----END PGP SIGNATURE----- # gpg: Signature made Thu 04 Jan 2024 04:30:07 GMT # gpg: using EDDSA key B9184DC20CC457DACF7DD1A93B5FCCCDF3ABD706 # gpg: issuer "peterx@redhat.com" # gpg: Good signature from "Peter Xu <xzpeter@gmail.com>" [unknown] # gpg: aka "Peter Xu <peterx@redhat.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: B918 4DC2 0CC4 57DA CF7D D1A9 3B5F CCCD F3AB D706 * tag 'migration-20240104-pull-request' of https://gitlab.com/peterx/qemu: (26 commits) migration: fix coverity migrate_mode finding migration/multifd: Remove unnecessary usage of local Error migration: Remove unnecessary usage of local Error migration: Fix migration_channel_read_peek() error path migration/multifd: Remove error_setg() in migration_ioc_process_incoming() migration/multifd: Fix leaking of Error in TLS error flow migration/multifd: Simplify multifd_channel_connect() if else statement migration/multifd: Fix error message in multifd_recv_initial_packet() migration: Remove errp parameter in migration_fd_process_incoming() migration: Refactor migration_incoming_setup() migration: Remove nulling of hostname in migrate_init() migration: Remove migrate_max_downtime() declaration tests/qtest: postcopy migration with suspend tests/qtest: precopy migration with suspend tests/qtest: option to suspend during migration tests/qtest: migration events migration: preserve suspended for bg_migration migration: preserve suspended for snapshot migration: preserve suspended runstate migration: propagate suspended runstate ... Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2024-01-04migration: preserve suspended for snapshotSteve Sistare1-10/+13
Restoring a snapshot can break a suspended guest. Snapshots suffer from the same suspended-state issues that affect live migration, plus they must handle an additional problematic scenario, which is that a running vm must remain running if it loads a suspended snapshot. To save, the existing vm_stop call now completely stops the suspended state. Finish with vm_resume to leave the vm in the state it had prior to the save, correctly restoring the suspended state. To load, if the snapshot is not suspended, then vm_stop + vm_resume correctly handles all states, and leaves the vm in the state it had prior to the load. However, if the snapshot is suspended, restoration is trickier. First, call vm_resume to restore the state to suspended so the current state matches the saved state. Then, if the pre-load state is running, call wakeup to resume running. Prior to these changes, the vm_stop to RUN_STATE_SAVE_VM and RUN_STATE_RESTORE_VM did not change runstate if the current state was suspended, but now it does, so allow these transitions. Signed-off-by: Steve Sistare <steven.sistare@oracle.com> Reviewed-by: Peter Xu <peterx@redhat.com> Link: https://lore.kernel.org/r/1704312341-66640-8-git-send-email-steven.sistare@oracle.com Signed-off-by: Peter Xu <peterx@redhat.com>
2023-12-30migration: Constify VMStateRichard Henderson1-5/+5
Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Message-Id: <20231221031652.119827-67-richard.henderson@linaro.org>
2023-12-29migration: Make VMStateDescription.subsections constRichard Henderson1-6/+6
Allow the array of pointers to itself be const. Propagate this through the copies of this field. Tested-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Message-Id: <20231221031652.119827-2-richard.henderson@linaro.org>
2023-12-21block: remove AioContext lockingStefan Hajnoczi1-22/+0
This is the big patch that removes aio_context_acquire()/aio_context_release() from the block layer and affected block layer users. There isn't a clean way to split this patch and the reviewers are likely the same group of people, so I decided to do it in one patch. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Paul Durrant <paul@xen.org> Message-ID: <20231205182011.1976568-7-stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-11-03util/uuid: Add UUID_STR_LEN definitionCédric Le Goater1-2/+2
qemu_uuid_unparse() includes a trailing NUL when writing the uuid string and the buffer size should be UUID_FMT_LEN + 1 bytes. Add a define for this size and use it where required. Cc: Fam Zheng <fam@euphon.net> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Juan Quintela <quintela@redhat.com> Reviewed-by: "Denis V. Lunev" <den@openvz.org> Signed-off-by: Cédric Le Goater <clg@redhat.com>
2023-11-01migration: Add tracepoints for downtime checkpointsPeter Xu1-5/+9
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>
2023-11-01migration: Add per vmstate downtime tracepointsPeter Xu1-4/+45
We have a bunch of savevm_section* tracepoints, they're good to analyze migration stream, but not always suitable if someone would like to analyze the migration downtime. Two major problems: - savevm_section* tracepoints are dumping all sections, we only care about the sections that contribute to the downtime - They don't have an identifier to show the type of sections, so no way to filter downtime information either easily. We can add type into the tracepoints, but instead of doing so, this patch kept them untouched, instead of adding a bunch of downtime specific tracepoints, so one can enable "vmstate_downtime*" tracepoints and get a full picture of how the downtime is distributed across iterative and non-iterative vmstate save/load. Note that here both save() and load() need to be traced, because both of them may contribute to the downtime. The contribution is not a simple "add them together", though: consider when the src is doing a save() of device1 while the dest can be load()ing for device2, so they can happen concurrently. Tracking both sides make sense because device load() and save() can be imbalanced, one device can save() super fast, but load() super slow, vice versa. We can't figure that out without tracing both. 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: <20231030163346.765724-4-peterx@redhat.com>
2023-11-01migration: Check in savevm_state_handler_insert for dupsPeter Xu1-0/+14
Before finally register one SaveStateEntry, we detect for duplicated entries. This could be helpful to notify us asap instead of get silent migration failures which could be hard to diagnose. For example, this patch will generate a message like this (if without previous fixes on x2apic) as long as we wants to boot a VM instance with "-smp 200,maxcpus=288,sockets=2,cores=72,threads=2" and QEMU will bail out even before VM starts: savevm_state_handler_insert: Detected duplicate SaveStateEntry: id=apic, instance_id=0x0 Suggested-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Message-ID: <20231020090731.28701-10-quintela@redhat.com>
2023-11-01migration: Hack to maintain backwards compatibility for ppcJuan Quintela1-0/+18
Current code does: - register pre_2_10_vmstate_dummy_icp with "icp/server" and instance dependinfg on cpu number - for newer machines, it register vmstate_icp with "icp/server" name and instance 0 - now it unregisters "icp/server" for the 1st instance. This is wrong at many levels: - we shouldn't have two VMSTATEDescriptions with the same name - In case this is the only solution that we can came with, it needs to be: * register pre_2_10_vmstate_dummy_icp * unregister pre_2_10_vmstate_dummy_icp * register real vmstate_icp Created vmstate_replace_hack_for_ppc() with warnings left and right that it is a hack. CC: Cedric Le Goater <clg@kaod.org> CC: Daniel Henrique Barboza <danielhb413@gmail.com> CC: David Gibson <david@gibson.dropbear.id.au> CC: Greg Kurz <groug@kaod.org> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Message-ID: <20231020090731.28701-8-quintela@redhat.com>
2023-10-31qemu-file: Make qemu_fflush() return errorsJuan Quintela1-2/+1
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>
2023-10-31qemu-file: Remove _noflush from qemu_file_transferred_noflush()Juan Quintela1-3/+3
qemu_file_transferred() don't exist anymore, so we can reuse the name. Reviewed-by: Fabiano Rosas <farosas@suse.de> Signed-off-by: Juan Quintela <quintela@redhat.com> Message-ID: <20231025091117.6342-7-quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-10-30migration: rename vmstate_save_needed->vmstate_section_neededMarc-André Lureau1-1/+1
The function is used on save at this point. The following commits will use it on load. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Message-ID: <20231024084043.2926316-5-marcandre.lureau@redhat.com>
2023-10-17migration: hold the BQL during setupFiona Ebner1-2/+0
This is intended to be a semantic revert of commit 9b09503752 ("migration: run setup callbacks out of big lock"). There have been so many changes since that commit (e.g. a new setup callback dirty_bitmap_save_setup() that also needs to be adapted now), it's easier to do the revert manually. For snapshots, the bdrv_writev_vmstate() function is used during setup (in QIOChannelBlock backing the QEMUFile), but not holding the BQL while calling it could lead to an assertion failure. To understand how, first note the following: 1. Generated coroutine wrappers for block layer functions spawn the coroutine and use AIO_WAIT_WHILE()/aio_poll() to wait for it. 2. If the host OS switches threads at an inconvenient time, it can happen that a bottom half scheduled for the main thread's AioContext is executed as part of a vCPU thread's aio_poll(). An example leading to the assertion failure is as follows: main thread: 1. A snapshot-save QMP command gets issued. 2. snapshot_save_job_bh() is scheduled. vCPU thread: 3. aio_poll() for the main thread's AioContext is called (e.g. when the guest writes to a pflash device, as part of blk_pwrite which is a generated coroutine wrapper). 4. snapshot_save_job_bh() is executed as part of aio_poll(). 3. qemu_savevm_state() is called. 4. qemu_mutex_unlock_iothread() is called. Now qemu_get_current_aio_context() returns 0x0. 5. bdrv_writev_vmstate() is executed during the usual savevm setup via qemu_fflush(). But this function is a generated coroutine wrapper, so it uses AIO_WAIT_WHILE. There, the assertion assert(qemu_get_current_aio_context() == qemu_get_aio_context()); will fail. To fix it, ensure that the BQL is held during setup. While it would only be needed for snapshots, adapting migration too avoids additional logic for conditional locking/unlocking in the setup callbacks. Writing the header could (in theory) also trigger qemu_fflush() and thus bdrv_writev_vmstate(), so the locked section also covers the qemu_savevm_state_header() call, even for migration for consistency. The section around multifd_send_sync_main() needs to be unlocked to avoid a deadlock. In particular, the multifd_save_setup() function calls socket_send_channel_create() using multifd_new_send_channel_async() as a callback and then waits for the callback to signal via the channels_ready semaphore. The connection happens via qio_task_run_in_thread(), but the callback is only executed via qio_task_thread_result() which is scheduled for the main event loop. Without unlocking the section, the main thread would never get to process the task result and the callback meaning there would be no signal via the channels_ready semaphore. The comment in ram_init_bitmaps() was introduced by 4987783400 ("migration: fix incorrect memory_global_dirty_log_start outside BQL") and is removed, because it referred to the qemu_mutex_lock_iothread() call. Signed-off-by: Fiona Ebner <f.ebner@proxmox.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: <20231013105839.415989-1-f.ebner@proxmox.com>
2023-10-17migration: Add the configuration vmstate to the json writerNikolay Borisov1-4/+16
Make the migration json writer part of MigrationState struct, allowing the 'configuration' object be serialized to json. This will facilitate the parsing of the 'configuration' object in the next patch that fixes analyze-migration.py for arm. Signed-off-by: Nikolay Borisov <nborisov@suse.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: <20231009184326.15777-2-farosas@suse.de>
2023-10-11migration: Allow RECOVER->PAUSED convertion for dest qemuPeter Xu1-1/+2
There's a bug on dest that if a double fault triggered on dest qemu (a network issue during postcopy-recover), we won't set PAUSED correctly because we assumed we always came from ACTIVE. Fix that by always overwriting the state to PAUSE. We could also check for these two states, but maybe it's an overkill. We did the same on the src QEMU to unconditionally switch to PAUSE anyway. Reviewed-by: Fabiano Rosas <farosas@suse.de> 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: <20231004220240.167175-10-peterx@redhat.com>
2023-10-04migration: Update error description outside migration.cTejus GK1-3/+14
A few code paths exist in the source code,where a migration is marked as failed via MIGRATION_STATUS_FAILED, but the failure happens outside of migration.c In such cases, an error_report() call is made, however the current MigrationState is never updated with the error description, and hence clients like libvirt never know the actual reason for the failure. This patch covers such cases outside of migration.c and updates the error description at the appropriate places. Acked-by: Peter Xu <peterx@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Tejus GK <tejus.gk@nutanix.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Message-ID: <20231003065538.244752-3-tejus.gk@nutanix.com>
2023-10-04migration/vmstate: Introduce vmstate_save_state_with_errTejus GK1-1/+1
Currently, a few code paths exist in the function vmstate_save_state_v, which ultimately leads to a migration failure. However, an update in the current MigrationState for the error description is never done. vmstate.c somehow doesn't seem to allow the use of migrate_set_error due to some dependencies for unit tests. Hence, this patch introduces a new function vmstate_save_state_with_err, which will eventually propagate the error message to savevm.c where a migrate_set_error call can be eventually done. Acked-by: Peter Xu <peterx@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Tejus GK <tejus.gk@nutanix.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Message-ID: <20231003065538.244752-2-tejus.gk@nutanix.com>
2023-09-11migration: Add .save_prepare() handler to struct SaveVMHandlersAvihai Horon1-1/+28
Add a new .save_prepare() handler to struct SaveVMHandlers. This handler is called early, even before migration starts, and can be used by devices to perform early checks. Refactor migrate_init() to be able to return errors and call .save_prepare() from there. Suggested-by: Peter Xu <peterx@redhat.com> Signed-off-by: Avihai Horon <avihaih@nvidia.com> Reviewed-by: Peter Xu <peterx@redhat.com> Reviewed-by: Cédric Le Goater <clg@redhat.com> Signed-off-by: Cédric Le Goater <clg@redhat.com>
2023-09-11migration: Move more initializations to migrate_init()Avihai Horon1-3/+0
Initialization of mig_stats, compression_counters and VFIO bytes transferred is hard-coded in migration code path and snapshot code path. Make the code cleaner by initializing them in migrate_init(). Suggested-by: Cédric Le Goater <clg@redhat.com> Signed-off-by: Avihai Horon <avihaih@nvidia.com> Reviewed-by: Cédric Le Goater <clg@redhat.com> Signed-off-by: Cédric Le Goater <clg@redhat.com>
2023-09-11migration: Add migration prefix to functions in target.cAvihai Horon1-1/+1
The functions in target.c are not static, yet they don't have a proper migration prefix. Add such prefix. Signed-off-by: Avihai Horon <avihaih@nvidia.com> Reviewed-by: Cédric Le Goater <clg@redhat.com> Signed-off-by: Cédric Le Goater <clg@redhat.com>
2023-07-26migration: Change qemu_file_transferred to noflushJuan Quintela1-1/+1
We do a qemu_fclose() just after that, that also does a qemu_fflush(), so remove one qemu_fflush(). Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Message-ID: <20230530183941.7223-3-quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-07-26qemu-file: Rename qemu_file_transferred_ fast -> noflushJuan Quintela1-2/+2
Fast don't say much. Noflush indicates more clearly that it is like qemu_file_transferred but without the flush. Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Message-ID: <20230530183941.7223-2-quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-07-25migration: spelling fixesMichael Tokarev1-1/+1
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru> Reviewed-by: Fabiano Rosas <farosas@suse.de>
2023-06-30vfio/migration: Reset bytes_transferred properlyAvihai Horon1-0/+1
Currently, VFIO bytes_transferred is not reset properly: 1. bytes_transferred is not reset after a VM snapshot (so a migration following a snapshot will report incorrect value). 2. bytes_transferred is a single counter for all VFIO devices, however upon migration failure it is reset multiple times, by each VFIO device. Fix it by introducing a new function vfio_reset_bytes_transferred() and calling it during migration and snapshot start. Remove existing bytes_transferred reset in VFIO migration state notifier, which is not needed anymore. Fixes: 3710586caa5d ("qapi: Add VFIO devices migration stats in Migration stats") Signed-off-by: Avihai Horon <avihaih@nvidia.com> Reviewed-by: Cédric Le Goater <clg@redhat.com> Reviewed-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Cédric Le Goater <clg@redhat.com>
2023-06-30migration: Implement switchover ack logicAvihai Horon1-0/+54
Implement switchover ack logic. This prevents the source from stopping the VM and completing the migration until an ACK is received from the destination that it's OK to do so. To achieve this, a new SaveVMHandlers handler switchover_ack_needed() and a new return path message MIG_RP_MSG_SWITCHOVER_ACK are added. The switchover_ack_needed() handler is called during migration setup in the destination to check if switchover ack is used by the migrated device. When switchover is approved by all migrated devices in the destination that support this capability, the MIG_RP_MSG_SWITCHOVER_ACK return path message is sent to the source to notify it that it's OK to do switchover. Signed-off-by: Avihai Horon <avihaih@nvidia.com> Reviewed-by: Peter Xu <peterx@redhat.com> Tested-by: YangHang Liu <yanghliu@redhat.com> Acked-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Cédric Le Goater <clg@redhat.com>
2023-06-02migration: never fail in global_state_store()Vladimir Sementsov-Ogievskiy1-5/+1
Actually global_state_store() can never fail. Let's get rid of extra error paths. To make things clear, use new runstate_get() and use same approach for global_state_store() and global_state_store_running(). Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Reviewed-by: Juan Quintela <quintela@redhat.com> Message-Id: <20230517123752.21615-3-vsementsov@yandex-team.ru> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-05-18migration: Move rate_limit_max and rate_limit_used to migration_statsJuan Quintela1-1/+1
These way we can make them atomic and use this functions from any place. I also moved all functions that use rate_limit to migration-stats. Functions got renamed, they are not qemu_file anymore. qemu_file_rate_limit -> migration_rate_exceeded qemu_file_set_rate_limit -> migration_rate_set qemu_file_get_rate_limit -> migration_rate_get qemu_file_reset_rate_limit -> migration_rate_reset qemu_file_acct_rate_limit -> migration_rate_account. Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Message-Id: <20230515195709.63843-6-quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-05-15qemu-file: Remove total from qemu_file_total_transferred_*()Juan Quintela1-3/+3
Function is already quite long. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Cédric Le Goater <clg@kaod.org> Message-Id: <20230508130909.65420-7-quintela@redhat.com>
2023-05-05qemu-file: Make total_transferred an uint64_tJuan Quintela1-4/+2
Change all the functions that use it. It was already passed as uint64_t. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Message-Id: <20230504113841.23130-8-quintela@redhat.com>
2023-05-03migration: Rename ram_counters to mig_statsJuan Quintela1-1/+1
migration_stats is just too long, and it is going to have more than ram counters in the near future. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Lukas Straub <lukasstraub2@web.de>
generated by cgit v1.1 at 2025-02-22 05:12:10 +0000