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2023-02-23migration/colo: Improve an x-colo-lost-heartbeat error messageMarkus Armbruster
The QERR_ macros are leftovers from the days of "rich" error objects. We've been trying to reduce their remaining use. Get rid of a use of QERR_FEATURE_DISABLED, and improve the somewhat imprecise error message (qemu) x_colo_lost_heartbeat Error: The feature 'colo' is not enabled to Error: VM is not in COLO mode Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20230207075115.1525-12-armbru@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Juan Quintela <quintela@redhat.com>
2023-02-23error: Drop superfluous #include "qapi/qmp/qerror.h"Markus Armbruster
Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20230207075115.1525-2-armbru@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Konstantin Kostiuk <kkostiuk@redhat.com>
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>
2023-02-15migration: In case of postcopy, the memory ends in res_postcopy_onlyJuan Quintela
So remove last assignation of res_compatible. Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-15migration/block: Convert remaining DPRINTF() debug macro to trace eventsPhilippe Mathieu-Daudé
Finish the conversion from commit fe80c0241d ("migration: using trace_ to replace DPRINTF"). Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-15migration/qemu-file: Add qemu_file_get_to_fd()Avihai Horon
Add new function qemu_file_get_to_fd() that allows reading data from QEMUFile and writing it straight into a given fd. This will be used later in VFIO migration code. Signed-off-by: Avihai Horon <avihaih@nvidia.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Reviewed-by: Cédric Le Goater <clg@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-13ram: Document migration ram flagsJuan Quintela
0x80 is RAM_SAVE_FLAG_HOOK, it is in qemu-file now. Bigger usable flag is 0x200, noticing that. We can reuse RAM_SAVe_FLAG_FULL. Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-13migration/multifd: Move load_cleanup inside incoming_state_destroyLeonardo Bras
Currently running migration_incoming_state_destroy() without first running multifd_load_cleanup() will cause a yank error: qemu-system-x86_64: ../util/yank.c:107: yank_unregister_instance: Assertion `QLIST_EMPTY(&entry->yankfns)' failed. (core dumped) The above error happens in the target host, when multifd is being used for precopy, and then postcopy is triggered and the migration finishes. This will crash the VM in the target host. To avoid that, move multifd_load_cleanup() inside migration_incoming_state_destroy(), so that the load cleanup becomes part of the incoming state destroying process. Running multifd_load_cleanup() twice can become an issue, though, but the only scenario it could be ran twice is on process_incoming_migration_bh(). So removing this extra call is necessary. On the other hand, this multifd_load_cleanup() call happens way before the migration_incoming_state_destroy() and having this happening before dirty_bitmap_mig_before_vm_start() and vm_start() may be a need. So introduce a new function multifd_load_shutdown() that will mainly stop all multifd threads and close their QIOChannels. Then use this function instead of multifd_load_cleanup() to make sure nothing else is received before dirty_bitmap_mig_before_vm_start(). Fixes: b5eea99ec2 ("migration: Add yank feature") Reported-by: Li Xiaohui <xiaohli@redhat.com> Signed-off-by: Leonardo Bras <leobras@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-13migration/multifd: Join all multifd threads in order to avoid leaksLeonardo Bras
Current approach will only join threads that are still running. For the threads not joined, resources or private memory are always kept in the process space and never reclaimed before process end, and this risks serious memory leaks. This should usually not represent a big problem, since multifd migration is usually just ran at most a few times, and after it succeeds there is not much to be done before exiting the process. Yet still, it should not hurt performance to join all of them. Fixes: b5eea99ec2 ("migration: Add yank feature") Reported-by: Li Xiaohui <xiaohli@redhat.com> Signed-off-by: Leonardo Bras <leobras@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-13migration/multifd: Remove unnecessary assignment on multifd_load_cleanup()Leonardo Bras
Before assigning "p->quit = true" for every multifd channel, multifd_load_cleanup() will call multifd_recv_terminate_threads() which already does the same assignment, while protected by a mutex. So there is no point doing the same assignment again. Fixes: b5eea99ec2 ("migration: Add yank feature") Reported-by: Li Xiaohui <xiaohli@redhat.com> Signed-off-by: Leonardo Bras <leobras@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-13migration/multifd: Change multifd_load_cleanup() signature and usageLeonardo Bras
Since it's introduction in commit f986c3d256 ("migration: Create multifd migration threads"), multifd_load_cleanup() never returned any value different than 0, neither set up any error on errp. Even though, on process_incoming_migration_bh() an if clause uses it's return value to decide on setting autostart = false, which will never happen. In order to simplify the codebase, change multifd_load_cleanup() signature to 'void multifd_load_cleanup(void)', and for every usage remove error handling or decision made based on return value != 0. Fixes: b5eea99ec2 ("migration: Add yank feature") Reported-by: Li Xiaohui <xiaohli@redhat.com> Signed-off-by: Leonardo Bras <leobras@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> 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: 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: Cleanup postcopy_preempt_setup()Peter Xu
Since we just dropped the only case where postcopy_preempt_setup() can return an error, it doesn't need a retval anymore because it never fails. Move the preempt check to the caller, preparing it to be used elsewhere to do nothing but as simple as kicking the async connection. 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>
2023-02-11AVX512 support for xbzrle_encode_bufferling xu
This commit is the same with [PATCH v6 1/2], and provides avx512 support for xbzrle_encode_buffer function to accelerate xbzrle encoding speed. Runtime check of avx512 support and benchmark for this feature are added. Compared with C version of xbzrle_encode_buffer function, avx512 version can achieve 50%-70% performance improvement on benchmarking. In addition, if dirty data is randomly located in 4K page, the avx512 version can achieve almost 140% performance gain. Signed-off-by: ling xu <ling1.xu@intel.com> Co-authored-by: Zhou Zhao <zhou.zhao@intel.com> Co-authored-by: Jun Jin <jun.i.jin@intel.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>
2023-02-11migration: Make ram_save_target_page() a pointerJuan Quintela
We are going to create a new function for multifd latest in the series. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2023-02-11migration: Calculate ram size onceJuan Quintela
We are recalculating ram size continously, when we know that it don't change during migration. Create a field in RAMState to track it. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
2023-02-11migration: Split ram_bytes_total_common() in two functionsJuan Quintela
It is just a big if in the middle of the function, and we need two functions anways. Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Signed-off-by: Juan Quintela <quintela@redhat.com> --- Reindent to make Phillipe happy (and CODING_STYLE)
2023-02-11migration: Make find_dirty_block() return a single parameterJuan Quintela
We used to return two bools, just return a single int with the following meaning: old return / again / new return false false PAGE_ALL_CLEAN false true PAGE_TRY_AGAIN true true PAGE_DIRTY_FOUND /* We don't care about again at all */ Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-11migration: Simplify ram_find_and_save_block()Juan Quintela
We will need later that find_dirty_block() return errors, so simplify the loop. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-11multifd: Remove some redundant codeLi Zhang
Clean up some unnecessary code Signed-off-by: Li Zhang <lizhang@suse.de> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-11multifd: cleanup the function multifd_channel_connectLi Zhang
Cleanup multifd_channel_connect Signed-off-by: Li Zhang <lizhang@suse.de> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-11migration: Remove spurious filesJuan Quintela
I introduced spurious files on my tree during a rebase: commit ebfc57871506b3fe36cc41f69ee3ad31a34afd63 Author: Zhenzhong Duan <zhenzhong.duan@intel.com> Date: Mon Oct 17 15:53:51 2022 +0800 multifd: Fix flush of zero copy page send request Make IO channel flush call after the inflight request has been drained in multifd thread, or else we may missed to flush the inflight request. Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com> To make things worse, it appears like Zhenzhong is the one to blame. for(int i=0; i < 1000000; i++) { printf("I will not do rebases when I am tired\n"); } Sorry, Juan. Reviewed-by: Cédric Le Goater <clg@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-08Drop duplicate #includeMarkus Armbruster
Tracked down with the help of scripts/clean-includes. Signed-off-by: Markus Armbruster <armbru@redhat.com> Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Greg Kurz <groug@kaod.org> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Message-Id: <20230202133830.2152150-21-armbru@redhat.com>
2023-02-06migration: save/delete migration thread infoJiang Jiacheng
To support query migration thread infomation, save and delete thread(live_migration and multifdsend) information at thread creation and finish. Signed-off-by: Jiang Jiacheng <jiangjiacheng@huawei.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-06migration: Introduce interface query-migrationthreadsJiang Jiacheng
Introduce interface query-migrationthreads. The interface is used to query information about migration threads and returns with migration thread's name and its id. Introduce threadinfo.c to manage threads with migration. Signed-off-by: Jiang Jiacheng <jiangjiacheng@huawei.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-06multifd: Fix flush of zero copy page send requestZhenzhong Duan
Make IO channel flush call after the inflight request has been drained in multifd thread, or else we may missed to flush the inflight request. Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-06multifd: Fix a race on reading MultiFDPages_t.blockZhenzhong Duan
In multifd_queue_page() MultiFDPages_t.block is checked twice. Between the two checks, MultiFDPages_t.block may be reset to NULL by multifd thread. This lead to the 2nd check always true then a redundant page submitted to multifd thread again. Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-06migration: check magic value for deciding the mapping of channelsmanish.mishra
Current logic assumes that channel connections on the destination side are always established in the same order as the source and the first one will always be the main channel followed by the multifid or post-copy preemption channel. This may not be always true, as even if a channel has a connection established on the source side it can be in the pending state on the destination side and a newer connection can be established first. Basically causing out of order mapping of channels on the destination side. Currently, all channels except post-copy preempt send a magic number, this patch uses that magic number to decide the type of channel. This logic is applicable only for precopy(multifd) live migration, as mentioned, the post-copy preempt channel does not send any magic number. Also, tls live migrations already does tls handshake before creating other channels, so this issue is not possible with tls, hence this logic is avoided for tls live migrations. This patch uses read peek to check the magic number of channels so that current data/control stream management remains un-effected. Reviewed-by: Peter Xu <peterx@redhat.com> Reviewed-by: Daniel P. Berrange <berrange@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Suggested-by: Daniel P. Berrange <berrange@redhat.com> Signed-off-by: manish.mishra <manish.mishra@nutanix.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-06io: Add support for MSG_PEEK for socket channelmanish.mishra
MSG_PEEK peeks at the channel, The data is treated as unread and the next read shall still return this data. This support is currently added only for socket class. Extra parameter 'flags' is added to io_readv calls to pass extra read flags like MSG_PEEK. Reviewed-by: Peter Xu <peterx@redhat.com> Reviewed-by: Daniel P. Berrange <berrange@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Suggested-by: Daniel P. Berrange <berrange@redhat.com> Signed-off-by: manish.mishra <manish.mishra@nutanix.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-06migration/dirtyrate: Show sample pages only in page-sampling modeZhenzhong Duan
The value of "Sample Pages" is confusing in mode other than page-sampling. See below: (qemu) calc_dirty_rate -b 10 520 (qemu) info dirty_rate Status: measuring Start Time: 11646834 (ms) Sample Pages: 520 (per GB) Period: 10 (sec) Mode: dirty-bitmap Dirty rate: (not ready) (qemu) info dirty_rate Status: measured Start Time: 11646834 (ms) Sample Pages: 0 (per GB) Period: 10 (sec) Mode: dirty-bitmap Dirty rate: 2 (MB/s) While it's totally useless in dirty-ring and dirty-bitmap mode, fix to show it only in page-sampling mode. Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com> Reviewed-by: Peter Xu <peterx@redhat.com> Reviewed-by: Juan Quintela <quintela@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/rdma: fix return value for qio_channel_rdma_{readv,writev}Fiona Ebner
upon errors. As the documentation in include/io/channel.h states, only -1 and QIO_CHANNEL_ERR_BLOCK should be returned upon error. Other values have the potential to confuse the call sites. error_setg is used rather than error_setg_errno, because there are certain code paths where -1 (as a non-errno) is propagated up (e.g. starting from qemu_rdma_block_for_wrid or qemu_rdma_post_recv_control) all the way to qio_channel_rdma_{readv,writev}. Similar to a216ec85b7 ("migration/channel-block: fix return value for qio_channel_block_{readv,writev}"). Suggested-by: Zhang Chen <chen.zhang@intel.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Fiona Ebner <f.ebner@proxmox.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-06migration: Show downtime during postcopy phasePeter Xu
The downtime should be displayed during postcopy phase because the switchover phase is done. OTOH it's weird to show "expected downtime" which can confuse what does that mean if the switchover has already happened anyway. This is a slight ABI change on QMP, but I assume it shouldn't affect anyone. Reviewed-by: Leonardo Bras <leobras@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-06migration/ram: Factor out check for advised postcopyDavid Hildenbrand
Let's factor out this check, to be used in virtio-mem context next. While at it, fix a spelling error in a related comment. 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: 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/ram: Optimize ram_write_tracking_start() for RamDiscardManagerDavid Hildenbrand
ram_block_populate_read() already optimizes for RamDiscardManager. However, ram_write_tracking_start() will still try protecting discarded memory ranges. Let's optimize, because discarded ranges don't map any pages and (1) For anonymous memory, trying to protect using uffd-wp without a mapped page is ignored by the kernel and consequently a NOP. (2) For shared/file-backed memory, we will fill present page tables in the range with PTE markers. However, we will even allocate page tables just to fill them with unnecessary PTE markers and effectively waste memory. So let's exclude these ranges, just like ram_block_populate_read() already does. Reviewed-by: Peter Xu <peterx@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/ram: Rely on used_length for uffd_change_protection()David Hildenbrand
ram_mig_ram_block_resized() will abort migration (including background snapshots) when resizing a RAMBlock. ram_block_populate_read() will only populate RAM up to used_length, so at least for anonymous memory protecting everything between used_length and max_length won't actually be protected and is just a NOP. So let's only protect everything up to used_length. Note: it still makes sense to register uffd-wp for max_length, such that RAM_UF_WRITEPROTECT is independent of a changing used_length. Reviewed-by: Peter Xu <peterx@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/ram: Don't explicitly unprotect when unregistering uffd-wpDavid Hildenbrand
When unregistering uffd-wp, older kernels before commit f369b07c86143 ("mm/uffd:reset write protection when unregister with wp-mode") won't clear the uffd-wp PTE bit. When re-registering uffd-wp, the previous uffd-wp PTE bits would trigger again. With above commit, the kernel will clear the uffd-wp PTE bits when unregistering itself. Consequently, we'll clear the uffd-wp PTE bits now twice -- whereby we don't care about clearing them at all: a new background snapshot will re-register uffd-wp and re-protect all memory either way. So let's skip the manual clearing of uffd-wp. If ever relevant, we could clear conditionally in uffd_unregister_memory() -- we just need a way to figure out more recent kernels. Reviewed-by: Peter Xu <peterx@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/ram: Fix error handling in ram_write_tracking_start()David Hildenbrand
If something goes wrong during uffd_change_protection(), we would miss to unregister uffd-wp and not release our reference. Fix it by performing the uffd_change_protection(true) last. Note that a uffd_change_protection(false) on the recovery path without a prior uffd_change_protection(false) is fine. Fixes: 278e2f551a09 ("migration: support UFFD write fault processing in ram_save_iterate()") Cc: qemu-stable@nongnu.org Reviewed-by: Peter Xu <peterx@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/ram: Fix populate_read_range()David Hildenbrand
Unfortunately, commit f7b9dcfbcf44 broke populate_read_range(): the loop end condition is very wrong, resulting in that function not populating the full range. Lets' fix that. Fixes: f7b9dcfbcf44 ("migration/ram: Factor out populating pages readable in ram_block_populate_pages()") Cc: qemu-stable@nongnu.org Reviewed-by: Peter Xu <peterx@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>
2023-02-06util/userfaultfd: Add uffd_open()Peter Xu
Add a helper to create the uffd handle. Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-06migration: simplify migration_iteration_run()Juan Quintela
Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@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>