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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: Add a semaphore to count PONGsPeter Xu
This is mostly useless, but useful for us to know whether the main channel is correctly established without changing the migration protocol. 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: Rework multi-channel checks on URIPeter Xu
The whole idea of multi-channel checks was not properly done, IMHO. Currently we check multi-channel in a lot of places, but actually that's not needed because we only need to check it right after we get the URI and that should be it. If the URI check succeeded, we should never need to check it again because we must have it. If it check fails, we should fail immediately on either the qmp_migrate or qmp_migrate_incoming, instead of failingg it later after the connection established. Neither should we fail any set capabiliities like what we used to do here: 5ad15e8614 ("migration: allow enabling mutilfd for specific protocol only", 2021-10-19) Because logically the URI will only be set later after the capability is set, so it doesn't make a lot of sense to check the URI type when setting the capability, because we're checking the cap with an old URI passed in, and that may not even be the URI we're going to use later. This patch mostly reverted all such checks for before, dropping the variable migrate_allow_multi_channels and helpers. Instead, add a common helper to check URI for multi-channels for either qmp_migrate and qmp_migrate_incoming and that should do all the proper checks. The failure will only trigger with the "migrate" or "migrate_incoming" command, or when user specified "-incoming xxx" where "xxx" is not "defer". Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-06migration/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>
2022-12-15migration: Remove old preempt code around state maintainancePeter Xu
With the new code to send pages in rp-return thread, there's little help to keep lots of the old code on maintaining the preempt state in migration thread, because the new way should always be faster.. Then if we'll always send pages in the rp-return thread anyway, we don't need those logic to maintain preempt state anymore because now we serialize things using the mutex directly instead of using those fields. It's very unfortunate to have those code for a short period, but that's still one intermediate step that we noticed the next bottleneck on the migration thread. Now what we can do best is to drop unnecessary code as long as the new code is stable to reduce the burden. It's actually a good thing because the new "sending page in rp-return thread" model is (IMHO) even cleaner and with better performance. Remove the old code that was responsible for maintaining preempt states, at the meantime also remove x-postcopy-preempt-break-huge parameter because with concurrent sender threads we don't really need to break-huge anymore. Reviewed-by: Dr. David Alan Gilbert <dgilbert@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>
2022-07-20migration: Add property x-postcopy-preempt-break-hugePeter Xu
Add a property field that can conditionally disable the "break sending huge page" behavior in postcopy preemption. By default it's enabled. It should only be used for debugging purposes, and we should never remove the "x-" prefix. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Manish Mishra <manish.mishra@nutanix.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20220707185511.27366-1-peterx@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2022-07-20migration: Create the postcopy preempt channel asynchronouslyPeter Xu
This patch allows the postcopy preempt channel to be created asynchronously. The benefit is that when the connection is slow, we won't take the BQL (and potentially block all things like QMP) for a long time without releasing. A function postcopy_preempt_wait_channel() is introduced, allowing the migration thread to be able to wait on the channel creation. The channel is always created by the main thread, in which we'll kick a new semaphore to tell the migration thread that the channel has created. We'll need to wait for the new channel in two places: (1) when there's a new postcopy migration that is starting, or (2) when there's a postcopy migration to resume. For the start of migration, we don't need to wait for this channel until when we want to start postcopy, aka, postcopy_start(). We'll fail the migration if we found that the channel creation failed (which should probably not happen at all in 99% of the cases, because the main channel is using the same network topology). For a postcopy recovery, we'll need to wait in postcopy_pause(). In that case if the channel creation failed, we can't fail the migration or we'll crash the VM, instead we keep in PAUSED state, waiting for yet another recovery. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Manish Mishra <manish.mishra@nutanix.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20220707185509.27311-1-peterx@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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 enablementPeter Xu
This patch enables postcopy-preempt feature. It contains two major changes to the migration logic: (1) Postcopy requests are now sent via a different socket from precopy background migration stream, so as to be isolated from very high page request delays. (2) For huge page enabled hosts: when there's postcopy requests, they can now intercept a partial sending of huge host pages on src QEMU. After this patch, we'll live migrate a VM with two channels for postcopy: (1) PRECOPY channel, which is the default channel that transfers background pages; and (2) POSTCOPY channel, which only transfers requested pages. There's no strict rule of which channel to use, e.g., if a requested page is already being transferred on precopy channel, then we will keep using the same precopy channel to transfer the page even if it's explicitly requested. In 99% of the cases we'll prioritize the channels so we send requested page via the postcopy channel as long as possible. On the source QEMU, when we found a postcopy request, we'll interrupt the PRECOPY channel sending process and quickly switch to the POSTCOPY channel. After we serviced all the high priority postcopy pages, we'll switch back to PRECOPY channel so that we'll continue to send the interrupted huge page again. There's no new thread introduced on src QEMU. On the destination QEMU, one new thread is introduced to receive page data from the postcopy specific socket (done in the preparation patch). This patch has a side effect: after sending postcopy pages, previously we'll assume the guest will access follow up pages so we'll keep sending from there. Now it's changed. Instead of going on with a postcopy requested page, we'll go back and continue sending the precopy huge page (which can be intercepted by a postcopy request so the huge page can be sent partially before). Whether that's a problem is debatable, because "assuming the guest will continue to access the next page" may not really suite when huge pages are used, especially if the huge page is large (e.g. 1GB pages). So that locality hint is much meaningless if huge pages are used. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20220707185504.27203-1-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
2022-07-20migration: Add postcopy-preempt capabilityPeter Xu
Firstly, postcopy already preempts precopy due to the fact that we do unqueue_page() first before looking into dirty bits. However that's not enough, e.g., when there're host huge page enabled, when sending a precopy huge page, a postcopy request needs to wait until the whole huge page that is sending to finish. That could introduce quite some delay, the bigger the huge page is the larger delay it'll bring. This patch adds a new capability to allow postcopy requests to preempt existing precopy page during sending a huge page, so that postcopy requests can be serviced even faster. Meanwhile to send it even faster, bypass the precopy stream by providing a standalone postcopy socket for sending requested pages. Since the new behavior will not be compatible with the old behavior, this will not be the default, it's enabled only when the new capability is set on both src/dst QEMUs. This patch only adds the capability itself, the logic will be added in follow up patches. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20220707185342.26794-2-peterx@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2022-05-16migration: Add migrate_use_tls() helperLeonardo Bras
A lot of places check parameters.tls_creds in order to evaluate if TLS is in use, and sometimes call migrate_get_current() just for that test. Add new helper function migrate_use_tls() in order to simplify testing for TLS usage. Signed-off-by: Leonardo Bras <leobras@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Message-Id: <20220513062836.965425-6-leobras@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2022-05-16migration: Add zero-copy-send parameter for QMP/HMP for LinuxLeonardo Bras
Add property that allows zero-copy migration of memory pages on the sending side, and also includes a helper function migrate_use_zero_copy_send() to check if it's enabled. No code is introduced to actually do the migration, but it allow future implementations to enable/disable this feature. On non-Linux builds this parameter is compiled-out. Signed-off-by: Leonardo Bras <leobras@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Acked-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20220513062836.965425-5-leobras@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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>
2022-04-21migration: Move migrate_allow_multifd and helpers into migration.cPeter Xu
This variable, along with its helpers, is used to detect whether multiple channel will be supported for migration. In follow up patches, there'll be other capability that requires multi-channels. Hence move it outside multifd specific code and make it public. Meanwhile rename it from "multifd" to "multi_channels" to show its real meaning. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20220331150857.74406-5-peterx@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2022-03-02migration: Add migration_incoming_transport_cleanup()Peter Xu
Add a helper to cleanup the transport listener. When do it, we should also null-ify the cleanup hook and the data, then it's even safe to call it multiple times. Move the socket_address_list cleanup altogether, because that's a mirror of the listener channels and only for the purpose of query-migrate. Hence when someone wants to cleanup the listener transport, it should also want to cleanup the socket list too, always. No functional change intended. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20220301083925.33483-15-peterx@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2022-03-02migration: Move static var in ram_block_from_stream() into globalPeter Xu
Static variable is very unfriendly to threading of ram_block_from_stream(). Move it into MigrationIncomingState. Make the incoming state pointer to be passed over to ram_block_from_stream() on both caller sites. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20220301083925.33483-8-peterx@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@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
2021-11-03migration: provide an error message to migration_cancel()Laurent Vivier
This avoids to call migrate_get_current() in the caller function whereas migration_cancel() already needs the pointer to the current migration state. Signed-off-by: Laurent Vivier <lvivier@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2021-07-26migration: Make from_dst_file accesses thread-safePeter Xu
Accessing from_dst_file is potentially racy in current code base like below: if (s->from_dst_file) do_something(s->from_dst_file); Because from_dst_file can be reset right after the check in another thread (rp_thread). One example is migrate_fd_cancel(). Use the same qemu_file_lock to protect it too, just like to_dst_file. When it's safe to access without lock, comment it. There's one special reference in migration_thread() that can be replaced by the newly introduced rp_thread_created flag. Reported-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Lukas Straub <lukasstraub2@web.de> Message-Id: <20210722175841.938739-3-peterx@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> with Peter's fixup
2021-07-26migration: Fix missing join() of rp_threadPeter Xu
It's possible that the migration thread skip the join() of the rp_thread in below race and crash on src right at finishing migration: migration_thread rp_thread ---------------- --------- migration_completion() (before rp_thread quits) from_dst_file=NULL [thread got scheduled out] s->rp_state.from_dst_file==NULL (skip join() of rp_thread) migrate_fd_cleanup() qemu_fclose(s->to_dst_file) yank_unregister_instance() assert(yank_find_entry()) <------- crash It could mostly happen with postcopy, but that shouldn't be required, e.g., I think it could also trigger with MIGRATION_CAPABILITY_RETURN_PATH set. It's suspected that above race could be the root cause of a recent (but rare) migration-test break reported by either Dave or PMM: https://lore.kernel.org/qemu-devel/YPamXAHwan%2FPPXLf@work-vm/ The issue is: from_dst_file is reset in the rp_thread, so if the thread reset it to NULL fast enough then the migration thread will assume there's no rp_thread at all. This could potentially cause more severe issue (e.g. crash) after the yank code. Fix it by using a boolean to keep "whether we've created rp_thread". Cc: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20210722175841.938739-2-peterx@redhat.com> Reviewed-by: Lukas Straub <lukasstraub2@web.de> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-06-08migration: Add cleanup hook for inwards migrationDr. David Alan Gilbert
Add a cleanup hook for incoming migration that gets called at the end as a way for a transport to allow cleanup. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Message-Id: <20210421112834.107651-4-dgilbert@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-05-14Merge remote-tracking branch ↵Peter Maydell
'remotes/thuth-gitlab/tags/pull-request-2021-05-14' into staging * Replace YAML anchors by extends in the gitlab-CI yaml files * Many small qtest fixes (e.g. to fix issues discovered by Coverity) * Poison more config switches in common code * Fix the failing Travis-CI and Cirrus-CI tasks # gpg: Signature made Fri 14 May 2021 12:17:39 BST # gpg: using RSA key 27B88847EEE0250118F3EAB92ED9D774FE702DB5 # gpg: issuer "thuth@redhat.com" # gpg: Good signature from "Thomas Huth <th.huth@gmx.de>" [full] # gpg: aka "Thomas Huth <thuth@redhat.com>" [full] # gpg: aka "Thomas Huth <huth@tuxfamily.org>" [full] # gpg: aka "Thomas Huth <th.huth@posteo.de>" [unknown] # Primary key fingerprint: 27B8 8847 EEE0 2501 18F3 EAB9 2ED9 D774 FE70 2DB5 * remotes/thuth-gitlab/tags/pull-request-2021-05-14: cirrus.yml: Fix the MSYS2 task pc-bios/s390-ccw: Fix inline assembly for older versions of Clang tests/qtest/migration-test: Use g_autofree to avoid leaks on error paths configure: Poison all current target-specific #defines migration: Move populate_vfio_info() into a separate file include/sysemu: Poison all accelerator CONFIG switches in common code tests: Avoid side effects inside g_assert() arguments tests/qtest/rtc-test: Remove pointless NULL check tests/qtest/tpm-util.c: Free memory with correct free function tests/migration-test: Fix "true" vs true tests/qtest/npcm7xx_pwm-test.c: Avoid g_assert_true() for non-test assertions tests/qtest/ahci-test.c: Calculate iso_size with 64-bit arithmetic util/compatfd.c: Replaced a malloc call with g_malloc. libqtest: refuse QTEST_QEMU_BINARY=qemu-kvm docs/devel/qgraph: add troubleshooting information libqos/qgraph: fix "UNAVAILBLE" typo gitlab-ci: Replace YAML anchors by extends (native_test_job) gitlab-ci: Replace YAML anchors by extends (native_build_job) gitlab-ci: Replace YAML anchors by extends (container_job) tests/docker/dockerfiles: Add ccache to containers where it was missing Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2021-05-14migration: Move populate_vfio_info() into a separate fileThomas Huth
The CONFIG_VFIO switch only works in target specific code. Since migration/migration.c is common code, the #ifdef does not have the intended behavior here. Move the related code to a separate file now which gets compiled via specific_ss instead. Fixes: 3710586caa ("qapi: Add VFIO devices migration stats in Migration stats") Message-Id: <20210414112004.943383-3-thuth@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Signed-off-by: Thomas Huth <thuth@redhat.com>
2021-05-13migration/ram: Handle RAM block resizes during precopyDavid Hildenbrand
Resizing while migrating is dangerous and does not work as expected. The whole migration code works on the usable_length of ram blocks and does not expect this to change at random points in time. In the case of precopy, the ram block size must not change on the source, after syncing the RAM block list in ram_save_setup(), so as long as the guest is still running on the source. Resizing can be trigger *after* (but not during) a reset in ACPI code by the guest - hw/arm/virt-acpi-build.c:acpi_ram_update() - hw/i386/acpi-build.c:acpi_ram_update() Use the ram block notifier to get notified about resizes. Let's simply cancel migration and indicate the reason. We'll continue running on the source. No harm done. Update the documentation. Postcopy will be handled separately. Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: David Hildenbrand <david@redhat.com> Message-Id: <20210429112708.12291-5-david@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Manual merge
2021-02-08migration: Clean up signed vs. unsigned XBZRLE cache-sizeMarkus Armbruster
73af8dd8d7 "migration: Make xbzrle_cache_size a migration parameter" (v2.11.0) made the new parameter unsigned (QAPI type 'size', uint64_t in C). It neglected to update existing code, which continues to use int64_t. migrate_xbzrle_cache_size() returns the new parameter. Adjust its return type. QMP query-migrate-cache-size returns migrate_xbzrle_cache_size(). Adjust its return type. migrate-set-parameters passes the new parameter to xbzrle_cache_resize(). Adjust its parameter type. xbzrle_cache_resize() passes it on to cache_init(). Adjust its parameter type. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Message-Id: <20210202141734.2488076-3-armbru@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-02-08migration: implementation of background snapshot threadAndrey Gruzdev
Introducing implementation of 'background' snapshot thread which in overall follows the logic of precopy migration while internally utilizes completely different mechanism to 'freeze' vmstate at the start of snapshot creation. This mechanism is based on userfault_fd with wr-protection support and is Linux-specific. Signed-off-by: Andrey Gruzdev <andrey.gruzdev@virtuozzo.com> Acked-by: Peter Xu <peterx@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Message-Id: <20210129101407.103458-5-andrey.gruzdev@virtuozzo.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-02-08migration: introduce 'background-snapshot' migration capabilityAndrey Gruzdev
Add new capability to 'qapi/migration.json' schema. Update migrate_caps_check() to validate enabled capability set against introduced one. Perform checks for required kernel features and compatibility with guest memory backends. Signed-off-by: Andrey Gruzdev <andrey.gruzdev@virtuozzo.com> Reviewed-by: Peter Xu <peterx@redhat.com> Acked-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20210129101407.103458-2-andrey.gruzdev@virtuozzo.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-10-26migration: Maintain postcopy faulted addressesPeter Xu
Maintain a list of faulted addresses on the destination host for which we're waiting on. This is implemented using a GTree rather than a real list to make sure even there're plenty of vCPUs/threads that are faulting, the lookup will still be fast with O(log(N)) (because we'll do that after placing each page). It should bring a slight overhead, but ideally that shouldn't be a big problem simply because in most cases the requested page list will be short. Actually we did similar things for postcopy blocktime measurements. This patch didn't use that simply because: (1) blocktime measurement is towards vcpu threads only, but here we need to record all faulted addresses, including main thread and external thread (like, DPDK via vhost-user). (2) blocktime measurement will require UFFD_FEATURE_THREAD_ID, but here we don't want to add that extra dependency on the kernel version since not necessary. E.g., we don't need to know which thread faulted on which page, we also don't care about multiple threads faulting on the same page. But we only care about what addresses are faulted so waiting for a page copying from src. (3) blocktime measurement is not enabled by default. However we need this by default especially for postcopy recover. Another thing to mention is that this patch introduced a new mutex to serialize the receivedmap and the page_requested tree, however that serialization does not cover other procedures like UFFDIO_COPY. Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20201021212721.440373-4-peterx@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-10-26migration: Introduce migrate_send_rp_message_req_pages()Peter Xu
This is another layer wrapper for sending a page request to the source VM. The new migrate_send_rp_message_req_pages() will be used elsewhere in coming patches. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20201021212721.440373-3-peterx@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-10-26migration: Open brace '{' following struct go on the same lineBihong Yu
Signed-off-by: Bihong Yu <yubihong@huawei.com> Reviewed-by: Chuan Zheng <zhengchuan@huawei.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Message-Id: <1603163448-27122-5-git-send-email-yubihong@huawei.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-09-25migration/tls: save hostname into MigrationStateChuan Zheng
hostname is need in multifd-tls, save hostname into MigrationState. Signed-off-by: Chuan Zheng <zhengchuan@huawei.com> Signed-off-by: Yan Jin <jinyan12@huawei.com> Message-Id: <1600139042-104593-2-git-send-email-zhengchuan@huawei.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-09-25migration: Rework migrate_send_rp_req_pages() functionPeter Xu
We duplicated the logic of maintaining the last_rb variable at both callers of this function. Pass *rb pointer into the function so that we can avoid duplicating the logic. Also, when we have the rb pointer, it's also easier to remove the original 2nd & 4th parameters, because both of them (name of the ramblock when needed, or the page size) can be fetched from the ramblock pointer too. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20200908203022.341615-3-peterx@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-09-09Use DECLARE_*CHECKER* macrosEduardo Habkost
Generated using: $ ./scripts/codeconverter/converter.py -i \ --pattern=TypeCheckMacro $(git grep -l '' -- '*.[ch]') Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Message-Id: <20200831210740.126168-12-ehabkost@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Message-Id: <20200831210740.126168-13-ehabkost@redhat.com> Message-Id: <20200831210740.126168-14-ehabkost@redhat.com> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
2020-09-09Move QOM typedefs and add missing includesEduardo Habkost
Some typedefs and macros are defined after the type check macros. This makes it difficult to automatically replace their definitions with OBJECT_DECLARE_TYPE. Patch generated using: $ ./scripts/codeconverter/converter.py -i \ --pattern=QOMStructTypedefSplit $(git grep -l '' -- '*.[ch]') which will split "typdef struct { ... } TypedefName" declarations. Followed by: $ ./scripts/codeconverter/converter.py -i --pattern=MoveSymbols \ $(git grep -l '' -- '*.[ch]') which will: - move the typedefs and #defines above the type check macros - add missing #include "qom/object.h" lines if necessary Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Message-Id: <20200831210740.126168-9-ehabkost@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Message-Id: <20200831210740.126168-10-ehabkost@redhat.com> Message-Id: <20200831210740.126168-11-ehabkost@redhat.com> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
2020-08-27migration: Rename class type checking macrosEduardo Habkost
Rename the macros to make them consistent with the MIGRATION_OBJ macro name. This will make future conversion to OBJECT_DECLARE* easier. Signed-off-by: Eduardo Habkost <ehabkost@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Tested-By: Roman Bolshakov <r.bolshakov@yadro.com> Message-Id: <20200825192110.3528606-51-ehabkost@redhat.com> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
2020-08-21migration: Add block-bitmap-mapping parameterMax Reitz
This migration parameter allows mapping block node names and bitmap names to aliases for the purpose of block dirty bitmap migration. This way, management tools can use different node and bitmap names on the source and destination and pass the mapping of how bitmaps are to be transferred to qemu (on the source, the destination, or even both with arbitrary aliases in the migration stream). While touching this code, fix a bug where bitmap names longer than 255 bytes would fail an assertion in qemu_put_counted_string(). Suggested-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200820150725.68687-2-mreitz@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2020-07-27migration/block-dirty-bitmap: cancel migration on shutdownVladimir Sementsov-Ogievskiy
If target is turned off prior to postcopy finished, target crashes because busy bitmaps are found at shutdown. Canceling incoming migration helps, as it removes all unfinished (and therefore busy) bitmaps. Similarly on source we crash in bdrv_close_all which asserts that all bdrv states are removed, because bdrv states involved into dirty bitmap migration are referenced by it. So, we need to cancel outgoing migration as well. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> Message-Id: <20200727194236.19551-17-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2020-07-27migration/block-dirty-bitmap: move mutex init to dirty_bitmap_mig_initVladimir Sementsov-Ogievskiy
No reasons to keep two public init functions. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Message-Id: <20200727194236.19551-11-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2020-06-01migration/colo.c: Use event instead of semaphoreLukas Straub
If multiple packets miscompare in a short timeframe, the semaphore value will be increased multiple times. This causes multiple checkpoints even if one would be sufficient. Fix this by using a event instead of a semaphore for triggering checkpoints. Now, checkpoint requests will be ignored until the checkpoint event is sent to colo-compare (which releases the miscompared packets). Benchmark results (iperf3): Client-to-server tcp: without patch: ~66 Mbit/s with patch: ~61 Mbit/s Server-to-client tcp: without patch: ~702 Kbit/s with patch: ~16 Mbit/s Signed-off-by: Lukas Straub <lukasstraub2@web.de> Message-Id: <fd601ba1beb524aada54ba66e87ebfc12cf4574b.1589193382.git.lukasstraub2@web.de> Reviewed-by: zhanghailiang <zhang.zhanghailiang@huawei.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-02-28multifd: Add multifd-zstd-level parameterJuan Quintela
This parameter specifies the zstd compression level. The next patch will put it to use. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Acked-by: Markus Armbruster <armbru@redhat.com>
2020-02-28multifd: Add multifd-zlib-level parameterJuan Quintela
This parameter specifies the zlib compression level. The next patch will put it to use. Signed-off-by: Juan Quintela <quintela@redhat.com> Acked-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-02-28multifd: Make no compression operations into its own structureJuan Quintela
It will be used later. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> --- No comp value needs to be zero.
2020-01-29multifd: Make multifd_load_setup() get an Error parameterJuan Quintela
We need to change the full chain to pass the Error parameter. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-01-29migration: Create migration_is_running()Juan Quintela
This function returns true if we are in the middle of a migration. It is like migration_is_setup_or_active() with CANCELLING and COLO. Adapt all callers that are needed. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-01-20migration: Rate limit inside host pagesDr. David Alan Gilbert
When using hugepages, rate limiting is necessary within each huge page, since a 1G huge page can take a significant time to send, so you end up with bursty behaviour. Fixes: 4c011c37ecb3 ("postcopy: Send whole huge pages") Reported-by: Lin Ma <LMa@suse.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2019-10-29migration: add new migration state wait-unplugJens Freimann
This patch adds a new migration state called wait-unplug. It is entered after the SETUP state if failover devices are present. It will transition into ACTIVE once all devices were succesfully unplugged from the guest. So if a guest doesn't respond or takes long to honor the unplug request the user will see the migration state 'wait-unplug'. In the migration thread we query failover devices if they're are still pending the guest unplug. When all are unplugged the migration continues. If one device won't unplug migration will stay in wait_unplug state. Signed-off-by: Jens Freimann <jfreimann@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Message-Id: <20191029114905.6856-9-jfreimann@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2019-09-12migration: Add validate-uuid capabilityYury Kotov
This capability realizes simple source validation by UUID. It's useful for live migration between hosts. Signed-off-by: Yury Kotov <yury-kotov@yandex-team.ru> Message-Id: <20190903162246.18524-2-yury-kotov@yandex-team.ru> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2019-08-16Merge remote-tracking branch ↵Peter Maydell
'remotes/armbru/tags/pull-include-2019-08-13-v2' into staging Header cleanup patches for 2019-08-13 # gpg: Signature made Fri 16 Aug 2019 12:39:12 BST # gpg: using RSA key 354BC8B3D7EB2A6B68674E5F3870B400EB918653 # gpg: issuer "armbru@redhat.com" # gpg: Good signature from "Markus Armbruster <armbru@redhat.com>" [full] # gpg: aka "Markus Armbruster <armbru@pond.sub.org>" [full] # Primary key fingerprint: 354B C8B3 D7EB 2A6B 6867 4E5F 3870 B400 EB91 8653 * remotes/armbru/tags/pull-include-2019-08-13-v2: (29 commits) sysemu: Split sysemu/runstate.h off sysemu/sysemu.h sysemu: Move the VMChangeStateEntry typedef to qemu/typedefs.h Include sysemu/sysemu.h a lot less Clean up inclusion of sysemu/sysemu.h numa: Move remaining NUMA declarations from sysemu.h to numa.h Include sysemu/hostmem.h less numa: Don't include hw/boards.h into sysemu/numa.h Include hw/boards.h a bit less Include hw/qdev-properties.h less Include qemu/main-loop.h less Include qemu/queue.h slightly less Include hw/hw.h exactly where needed Include qom/object.h slightly less Include exec/memory.h slightly less Include migration/vmstate.h less migration: Move the VMStateDescription typedef to typedefs.h Clean up inclusion of exec/cpu-common.h Include hw/irq.h a lot less typedefs: Separate incomplete types and function types ide: Include hw/ide/internal a bit less outside hw/ide/ ... Signed-off-by: Peter Maydell <peter.maydell@linaro.org>