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2023-10-30migration: rename vmstate_save_needed->vmstate_section_neededMarc-André Lureau
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 Ebner
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 Borisov
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 Xu
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 GK
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 GK
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 Horon
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 Horon
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 Horon
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 Quintela
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 Quintela
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 Tokarev
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru> Reviewed-by: Fabiano Rosas <farosas@suse.de>
2023-06-30vfio/migration: Reset bytes_transferred properlyAvihai Horon
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 Horon
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-Ogievskiy
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 Quintela
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 Quintela
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 Quintela
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 Quintela
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>
2023-05-03migration: Move ram_stats to its own file migration-stats.[ch]Juan Quintela
There is already include/qemu/stats.h, so stats.h was a bad idea. We want this file to not depend on anything else, we will move all the migration counters/stats to this struct. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Lukas Straub <lukasstraub2@web.de>
2023-04-27migration/vmstate-dump: Dump array size too as "num"Peter Xu
For VMS_ARRAY typed vmsd fields, also dump the number of entries in the array in -vmstate-dump. Without such information, vmstate static checker can report false negatives of incompatible vmsd on VMS_ARRAY typed fields, when the src/dst do not have the same type of array defined. It's because in the checker we only check against size of fields within a VMSD field. One example: e1000e used to have a field defined as a boolean array with 5 entries, then removed it and replaced it with UNUSED (in 31e3f318c8b535): - VMSTATE_BOOL_ARRAY(core.eitr_intr_pending, E1000EState, - E1000E_MSIX_VEC_NUM), + VMSTATE_UNUSED(E1000E_MSIX_VEC_NUM), It's a legal replacement but vmstate static checker is not happy with it, because it checks only against the "size" field between the two fields (here one is BOOL_ARRAY, the other is UNUSED): For BOOL_ARRAY: { "field": "core.eitr_intr_pending", "version_id": 0, "field_exists": false, "size": 1 }, For UNUSED: { "field": "unused", "version_id": 0, "field_exists": false, "size": 5 }, It's not the script to blame because there's just not enough information dumped to show the total size of the entry for an array. Add it. Note that this will not break old vmstate checker because the field will just be ignored. Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-04-27migration: Allow postcopy_ram_supported_by_host() to report errPeter Xu
Instead of print it to STDERR, bring the error upwards so that it can be reported via QMP responses. E.g.: { "execute": "migrate-set-capabilities" , "arguments": { "capabilities": [ { "capability": "postcopy-ram", "state": true } ] } } { "error": { "class": "GenericError", "desc": "Postcopy is not supported: Host backend files need to be TMPFS or HUGETLBFS only" } } Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-04-24migration: Move migrate_use_block() to options.cJuan Quintela
Once that we are there, we rename the function to migrate_block() to be consistent with all other capabilities. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
2023-04-24migration: Create options.cJuan Quintela
We move there all capabilities helpers from migration.c. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> --- Following David advise: - looked through the history, capabilities are newer than 2012, so we can remove that bit of the header. - This part is posterior to Anthony. Original Author is Orit. Once there, I put myself. Peter Xu also did quite a bit of work here. Anyone else wants/needs to be there? I didn't search too hard because nobody asked before to be added. What do you think?
2023-04-24migration: rename enabled_capabilities to capabilitiesJuan Quintela
It is clear from the context what that means, and such a long name with the extra long names of the capabilities make very difficilut to stay inside the 80 columns limit. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
2023-02-15migration: Rename res_{postcopy,precopy}_onlyJuan Quintela
Once that res_compatible is removed, they don't make sense anymore. We remove the _only preffix. And to make things clearer we rename them to must_precopy and can_postcopy. Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-15migration: Remove unused res_compatibleJuan Quintela
Nothing assigns to it after previous commit. Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-11migration: Postpone postcopy preempt channel to be after mainPeter Xu
Postcopy with preempt-mode enabled needs two channels to communicate. The order of channel establishment is not guaranteed. It can happen that the dest QEMU got the preempt channel connection request before the main channel is established, then the migration may make no progress even during precopy due to the wrong order. To fix it, create the preempt channel only if we know the main channel is established. For a general postcopy migration, we delay it until postcopy_start(), that's where we already went through some part of precopy on the main channel. To make sure dest QEMU has already established the channel, we wait until we got the first PONG received. That's something we do at the start of precopy when postcopy enabled so it's guaranteed to happen sooner or later. For a postcopy recovery, we delay it to qemu_savevm_state_resume_prepare() where we'll have round trips of data on bitmap synchronizations, which means the main channel must have been established. Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-11migration: I messed state_pending_exact/estimateJuan Quintela
I called the helper function from the wrong top level function. This code was introduced in: commit c8df4a7aeffcb46020f610526eea621fa5b0cd47 Author: Juan Quintela <quintela@redhat.com> Date: Mon Oct 3 02:00:03 2022 +0200 migration: Split save_live_pending() into state_pending_* We split the function into to: - state_pending_estimate: We estimate the remaining state size without stopping the machine. - state pending_exact: We calculate the exact amount of remaining state. Thanks to Avihai Horon <avihaih@nvidia.com> for finding it. Fixes:c8df4a7aeffcb46020f610526eea621fa5b0cd47 When we introduced that patch, we enden calling state_pending_estimate() helper from qemu_savevm_statepending_exact() and state_pending_exact() helper from qemu_savevm_statepending_estimate() This patch fixes it. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-06migration: Perform vmsd structure check during testsDr. David Alan Gilbert
Perform a check on vmsd structures during test runs in the hope of catching any missing terminators and other simple screwups. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-06migration: Add canary to VMSTATE_END_OF_LISTDr. David Alan Gilbert
We fairly regularly forget VMSTATE_END_OF_LIST markers off descriptions; given that the current check is only for ->name being NULL, sometimes we get unlucky and the code apparently works and no one spots the error. Explicitly add a flag, VMS_END that should be set, and assert it is set during the traversal. Note: This can't go in until we update the copy of vmstate.h in slirp. Suggested-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-06migration/savevm: Allow immutable device state to be migrated early (i.e., ↵David Hildenbrand
before RAM) For virtio-mem, we want to have the plugged/unplugged state of memory blocks available before migrating any actual RAM content, and perform sanity checks before touching anything on the destination. This information is immutable on the migration source while migration is active, We want to use this information for proper preallocation support with migration: currently, we don't preallocate memory on the migration target, and especially with hugetlb, we can easily run out of hugetlb pages during RAM migration and will crash (SIGBUS) instead of catching this gracefully via preallocation. Migrating device state via a VMSD before we start iterating is currently impossible: the only approach that would be possible is avoiding a VMSD and migrating state manually during save_setup(), to be restored during load_state(). Let's allow for migrating device state via a VMSD early, during the setup phase in qemu_savevm_state_setup(). To keep it simple, we indicate applicable VMSD's using an "early_setup" flag. Note that only very selected devices (i.e., ones seriously messing with RAM setup) are supposed to make use of such early state migration. While at it, also use a bool for the "unmigratable" member. Reviewed-by: Peter Xu <peterx@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com>S Signed-off-by: David Hildenbrand <david@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-06migration/savevm: Prepare vmdesc json writer in qemu_savevm_state_setup()David Hildenbrand
... and store it in the migration state. This is a preparation for storing selected vmds's already in qemu_savevm_state_setup(). Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: David Hildenbrand <david@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-06migration/savevm: Move more savevm handling into vmstate_save()David Hildenbrand
Let's move more code into vmstate_save(), reducing code duplication and preparing for reuse of vmstate_save() in qemu_savevm_state_setup(). We have to move vmstate_save() to make the compiler happy. We'll now also trace from qemu_save_device_state(), triggering the same tracepoints as previously called from qemu_savevm_state_complete_precopy_non_iterable() only. Note that qemu_save_device_state() ignores iterable device state, such as RAM, and consequently doesn't trigger some other trace points (e.g., trace_savevm_state_setup()). Reviewed-by: Peter Xu <peterx@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: David Hildenbrand <david@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-06migration: Remove unused threshold_size parameterJuan Quintela
Until previous commit, save_live_pending() was used for ram. Now with the split into state_pending_estimate() and state_pending_exact() it is not needed anymore, so remove them. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2023-02-06migration: Split save_live_pending() into state_pending_*Juan Quintela
We split the function into to: - state_pending_estimate: We estimate the remaining state size without stopping the machine. - state pending_exact: We calculate the exact amount of remaining state. The only "device" that implements different functions for _estimate() and _exact() is ram. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2023-02-06migration: No save_live_pending() method uses the QEMUFile parameterJuan Quintela
So remove it everywhere. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2023-01-20include/block: Untangle inclusion loopsMarkus Armbruster
We have two inclusion loops: block/block.h -> block/block-global-state.h -> block/block-common.h -> block/blockjob.h -> block/block.h block/block.h -> block/block-io.h -> block/block-common.h -> block/blockjob.h -> block/block.h I believe these go back to Emanuele's reorganization of the block API, merged a few months ago in commit d7e2fe4aac8. Fortunately, breaking them is merely a matter of deleting unnecessary includes from headers, and adding them back in places where they are now missing. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20221221133551.3967339-2-armbru@redhat.com>
2022-10-27reset: allow registering handlers that aren't called by snapshot loadingJason A. Donenfeld
Snapshot loading only expects to call deterministic handlers, not non-deterministic ones. So introduce a way of registering handlers that won't be called when reseting for snapshots. Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Message-id: 20221025004327.568476-2-Jason@zx2c4.com [PMM: updated json doc comment with Markus' text; fixed checkpatch style nit] Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2022-07-20migration: Postcopy recover with preempt enabledPeter Xu
To allow postcopy recovery, the ram fast load (preempt-only) dest QEMU thread needs similar handling on fault tolerance. When ram_load_postcopy() fails, instead of stopping the thread it halts with a semaphore, preparing to be kicked again when recovery is detected. A mutex is introduced to make sure there's no concurrent operation upon the socket. To make it simple, the fast ram load thread will take the mutex during its whole procedure, and only release it if it's paused. The fast-path socket will be properly released by the main loading thread safely when there's network failures during postcopy with that mutex held. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20220707185506.27257-1-peterx@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2022-07-20migration: Postcopy preemption preparation on channel creationPeter Xu
Create a new socket for postcopy to be prepared to send postcopy requested pages via this specific channel, so as to not get blocked by precopy pages. A new thread is also created on dest qemu to receive data from this new channel based on the ram_load_postcopy() routine. The ram_load_postcopy(POSTCOPY) branch and the thread has not started to function, and that'll be done in follow up patches. Cleanup the new sockets on both src/dst QEMUs, meanwhile look after the new thread too to make sure it'll be recycled properly. Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20220707185502.27149-1-peterx@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> dgilbert: With Peter's fix to quieten compiler warning on start_migration
2022-06-23migration: remove the QEMUFileOps abstractionDaniel P. Berrangé
Now that all QEMUFile callbacks are removed, the entire concept can be deleted. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2022-06-22migration: convert savevm to use QIOChannelBlock for VMStateDaniel P. Berrangé
With this change, all QEMUFile usage is backed by QIOChannel at last. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> dgilbert: Wrap long lines
2022-06-22migration: rename qemu_ftell to qemu_file_total_transferredDaniel P. Berrangé
The name 'ftell' gives the misleading impression that the QEMUFile objects are seekable. This is not the case, as in general we just have an opaque stream. The users of this method are only interested in the total bytes processed. This switches to a new name that reflects the intended usage. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> dgilbert: Wrapped long line
2022-04-21migration: Allow migrate-recover to run multiple timesPeter Xu
Previously migration didn't have an easy way to cleanup the listening transport, migrate recovery only allows to execute once. That's done with a trick flag in postcopy_recover_triggered. Now the facility is already there. Drop postcopy_recover_triggered and instead allows a new migrate-recover to release the previous listener transport. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20220331150857.74406-8-peterx@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2022-03-04include/block/snapshot: global state API + assertionsEmanuele Giuseppe Esposito
Snapshots run also under the BQL, so they all are in the global state API. The aiocontext lock that they hold is currently an overkill and in future could be removed. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Message-Id: <20220303151616.325444-23-eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2022-03-04block: rename bdrv_invalidate_cache_all, blk_invalidate_cache and ↵Emanuele Giuseppe Esposito
test_sync_op_invalidate_cache Following the bdrv_activate renaming, change also the name of the respective callers. bdrv_invalidate_cache_all -> bdrv_activate_all blk_invalidate_cache -> blk_activate test_sync_op_invalidate_cache -> test_sync_op_activate No functional change intended. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Message-Id: <20220209105452.1694545-5-eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2022-03-02migration: Add postcopy_thread_create()Peter Xu
Postcopy create threads. A common manner is we init a sem and use it to sync with the thread. Namely, we have fault_thread_sem and listen_thread_sem and they're only used for this. Make it a shared infrastructure so it's easier to create yet another thread. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20220301083925.33483-7-peterx@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2022-03-02migration: Introduce postcopy channels on dest nodePeter Xu
Postcopy handles huge pages in a special way that currently we can only have one "channel" to transfer the page. It's because when we install pages using UFFDIO_COPY, we need to have the whole huge page ready, it also means we need to have a temp huge page when trying to receive the whole content of the page. Currently all maintainance around this tmp page is global: firstly we'll allocate a temp huge page, then we maintain its status mostly within ram_load_postcopy(). To enable multiple channels for postcopy, the first thing we need to do is to prepare N temp huge pages as caching, one for each channel. Meanwhile we need to maintain the tmp huge page status per-channel too. To give some example, some local variables maintained in ram_load_postcopy() are listed; they are responsible for maintaining temp huge page status: - all_zero: this keeps whether this huge page contains all zeros - target_pages: this counts how many target pages have been copied - host_page: this keeps the host ptr for the page to install Move all these fields to be together with the temp huge pages to form a new structure called PostcopyTmpPage. Then for each (future) postcopy channel, we need one structure to keep the state around. For vanilla postcopy, obviously there's only one channel. It contains both precopy and postcopy pages. This patch teaches the dest migration node to start realize the possible number of postcopy channels by introducing the "postcopy_channels" variable. Its value is calculated when setup postcopy on dest node (during POSTCOPY_LISTEN phase). Vanilla postcopy will have channels=1, but when postcopy-preempt capability is enabled (in the future), we will boost it to 2 because even during partial sending of a precopy huge page we still want to preempt it and start sending the postcopy requested page right away (so we start to keep two temp huge pages; more if we want to enable multifd). In this patch there's a TODO marked for that; so far the channels is always set to 1. We need to send one "host huge page" on one channel only and we cannot split them, because otherwise the data upon the same huge page can locate on more than one channel so we need more complicated logic to manage. One temp host huge page for each channel will be enough for us for now. Postcopy will still always use the index=0 huge page even after this patch. However it prepares for the latter patches where it can start to use multiple channels (which needs src intervention, because only src knows which channel we should use). Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20220301083925.33483-5-peterx@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> dgilbert: Fixed up long line
2022-03-02migration: Tracepoint change in postcopy-run bottom halfPeter Xu
Remove the old two tracepoints and they're even near each other: trace_loadvm_postcopy_handle_run_cpu_sync() trace_loadvm_postcopy_handle_run_vmstart() Add trace_loadvm_postcopy_handle_run_bh() with a finer granule trace. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20220301083925.33483-4-peterx@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>