aboutsummaryrefslogtreecommitdiff
path: root/include/migration/register.h
AgeCommit message (Collapse)AuthorFilesLines
2024-04-23migration: Add Error** argument to .load_setup() handlerCédric Le Goater1-1/+2
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 Goater1-1/+2
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>
2024-03-11migration: Add documentation for SaveVMHandlersCédric Le Goater1-26/+237
The SaveVMHandlers structure is still in use for complex subsystems and devices. Document the handlers since we are going to modify a few later. Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Cédric Le Goater <clg@redhat.com> Link: https://lore.kernel.org/r/20240304122844.1888308-9-clg@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-11migration: Remove SaveStateHandler and LoadStateHandler typedefsCédric Le Goater1-2/+2
They are only used once. Reviewed-by: Fabiano Rosas <farosas@suse.de> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Cédric Le Goater <clg@redhat.com> Link: https://lore.kernel.org/r/20240304122844.1888308-8-clg@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com>
2024-01-08Replace "iothread lock" with "BQL" in commentsStefan Hajnoczi1-4/+4
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>
2023-10-17migration: hold the BQL during setupFiona Ebner1-1/+1
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>
2023-09-11migration: Add .save_prepare() handler to struct SaveVMHandlersAvihai Horon1-0/+5
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>
2023-06-30migration: Implement switchover ack logicAvihai Horon1-0/+2
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>
2023-02-15migration: Rename res_{postcopy,precopy}_onlyJuan Quintela1-12/+15
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 Quintela1-5/+2
Nothing assigns to it after previous commit. Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-06migration: Remove unused threshold_size parameterJuan Quintela1-2/+0
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 Quintela1-7/+12
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 Quintela1-1/+1
So remove it everywhere. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-01-20migration: Change SaveStateEntry.instance_id into uint32_tPeter Xu1-1/+1
It was always used as 32bit, so define it as used to be clear. Instead of using -1 as the auto-gen magic value, we switch to UINT32_MAX. We also make sure that we don't auto-gen this value to avoid overflowed instance IDs without being noticed. Suggested-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2020-01-06vmstate: replace DeviceState with VMStateIfMarc-André Lureau1-1/+1
Replace DeviceState dependency with VMStateIf on vmstate API. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Acked-by: Halil Pasic <pasic@linux.ibm.com>
2020-01-06vmstate: add qom interface to get idMarc-André Lureau1-0/+2
Add an interface to get the instance id, instead of depending on Device and qdev_get_dev_path(). Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2019-09-12migration: register_savevm_live doesn't need devDr. David Alan Gilbert1-2/+1
Commit 78dd48df3 removed the last caller of register_savevm_live for an instantiable device (rather than a single system wide device); so trim out the parameter. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Message-Id: <20190822115433.12070-1-dgilbert@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2019-01-23vmstate: constify SaveVMHandlersMarc-André Lureau1-1/+1
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <20181114133139.27346-1-marcandre.lureau@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2018-05-15migration: introduce SaveVMHandlers.resume_preparePeter Xu1-0/+2
This is hook function to be called when a postcopy migration wants to resume from a failure. For each module, it should provide its own recovery logic before we switch to the postcopy-active state. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20180502104740.12123-16-peterx@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2018-03-13migration: add is_active_iterate handlerVladimir Sementsov-Ogievskiy1-0/+9
Only-postcopy savevm states (dirty-bitmap) don't need live iteration, so to disable them and stop transporting empty sections there is a new savevm handler. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Message-id: 20180313180320.339796-10-vsementsov@virtuozzo.com
2018-03-13migration: introduce postcopy-only pendingVladimir Sementsov-Ogievskiy1-2/+15
There would be savevm states (dirty-bitmap) which can migrate only in postcopy stage. The corresponding pending is introduced here. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Message-id: 20180313180320.339796-6-vsementsov@virtuozzo.com
2017-09-22migration: add has_postcopy savevm handlerVladimir Sementsov-Ogievskiy1-0/+1
Now postcopy-able states are recognized by not NULL save_live_complete_postcopy handler. But when we have several different postcopy-able states, it is not convenient. Ram postcopy may be disabled, while some other postcopy enabled, in this case Ram state should behave as it is not postcopy-able. This patch add separate has_postcopy handler to specify behaviour of savevm state. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2017-07-10migration: Create load_setup()/cleanup() methodsJuan Quintela1-0/+2
We need to do things at load time and at cleanup time. Signed-off-by: Juan Quintela <quintela@redhat.com> -- Move the printing of the error message so we can print the device giving the error. Add call to postcopy stuff Message-Id: <20170628095228.4661-4-quintela@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2017-07-10migration: Rename cleanup() to save_cleanup()Juan Quintela1-1/+1
We need a cleanup for loads, so we rename here to be consistent. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> -- Rename htab_cleanup to htap_save_cleanup as dave suggestion Message-Id: <20170628095228.4661-3-quintela@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2017-07-10migration: Rename save_live_setup() to save_setup()Juan Quintela1-1/+1
We are going to use it now for more than save live regions. Once there rename qemu_savevm_state_begin() to qemu_savevm_state_setup(). Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Message-Id: <20170628095228.4661-2-quintela@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2017-06-14migration: Fix compilation with older compilersJuan Quintela1-3/+0
That typedefs are needed on both files. New compilers (F25 where I work) don't complain about repeating a typedef. But older ones complain. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Greg Kurz <groug@kaod.org>
2017-06-13migration: Split registration functions from vmstate.hJuan Quintela1-0/+56
They are indpendent, and nowadays almost every device register things with qdev->vmsd. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Reviewed-by: Peter Xu <peterx@redhat.com>
generated by cgit v1.1 at 2024-10-19 04:52:08 +0000