Helper to say if we are doing a migration over rdma.
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231011203527.9061-2-quintela@redhat.com>
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>
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>
Migration bandwidth is a very important value to live migration. It's
because it's one of the major factors that we'll make decision on when to
switchover to destination in a precopy process.
This value is currently estimated by QEMU during the whole live migration
process by monitoring how fast we were sending the data. This can be the
most accurate bandwidth if in the ideal world, where we're always feeding
unlimited data to the migration channel, and then it'll be limited to the
bandwidth that is available.
However in reality it may be very different, e.g., over a 10Gbps network we
can see query-migrate showing migration bandwidth of only a few tens of
MB/s just because there are plenty of other things the migration thread
might be doing. For example, the migration thread can be busy scanning
zero pages, or it can be fetching dirty bitmap from other external dirty
sources (like vhost or KVM). It means we may not be pushing data as much
as possible to migration channel, so the bandwidth estimated from "how many
data we sent in the channel" can be dramatically inaccurate sometimes.
With that, the decision to switchover will be affected, by assuming that we
may not be able to switchover at all with such a low bandwidth, but in
reality we can.
The migration may not even converge at all with the downtime specified,
with that wrong estimation of bandwidth, keeping iterations forever with a
low estimation of bandwidth.
The issue is QEMU itself may not be able to avoid those uncertainties on
measuing the real "available migration bandwidth". At least not something
I can think of so far.
One way to fix this is when the user is fully aware of the available
bandwidth, then we can allow the user to help providing an accurate value.
For example, if the user has a dedicated channel of 10Gbps for migration
for this specific VM, the user can specify this bandwidth so QEMU can
always do the calculation based on this fact, trusting the user as long as
specified. It may not be the exact bandwidth when switching over (in which
case qemu will push migration data as fast as possible), but much better
than QEMU trying to wildly guess, especially when very wrong.
A new parameter "avail-switchover-bandwidth" is introduced just for this.
So when the user specified this parameter, instead of trusting the
estimated value from QEMU itself (based on the QEMUFile send speed), it
trusts the user more by using this value to decide when to switchover,
assuming that we'll have such bandwidth available then.
Note that specifying this value will not throttle the bandwidth for
switchover yet, so QEMU will always use the full bandwidth possible for
sending switchover data, assuming that should always be the most important
way to use the network at that time.
This can resolve issues like "unconvergence migration" which is caused by
hilarious low "migration bandwidth" detected for whatever reason.
Reported-by: Zhiyi Guo <zhguo@redhat.com>
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
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: <20231010221922.40638-1-peterx@redhat.com>
Current migration_completion function is a bit long. Refactor the long
implementation into different subfunctions:
- migration_completion_precopy: completion code related to precopy
- migration_completion_postcopy: completion code related to postcopy
Rename await_return_path_close_on_source to
close_return_path_on_source: It is renamed to match with
open_return_path_on_source.
This improves readability and is easier for future updates (e.g. add new
subfunctions when completion code related to new features are needed). No
functional changes intended.
Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Isaku Yamahata <isaku.yamahata@intel.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230804093053.5037-1-wei.w.wang@intel.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
It's just a simple wrapper for rp_sem on either wait() or kick(), make it
even clearer on how it is used. Prepared to be used even for other things.
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-ID: <20231004220240.167175-8-peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Introduce a helper to detect whether MigrationState.error is set for
whatever reason.
This is preparation work for any thread (e.g. source return path thread) to
setup errors in an unified way to MigrationState, rather than relying on
its own way to set errors (mark_source_rp_bad()).
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: <20231004220240.167175-3-peterx@redhat.com>
Display it as long as being set, irrelevant of FAILED status. E.g., it may
also be applicable to PAUSED stage of postcopy, to provide hint on what has
gone wrong.
The error_mutex seems to be overlooked when referencing the error, add it
to be very safe.
This will change QAPI behavior by showing up error message outside !FAILED
status, but it's intended and doesn't expect to break anyone.
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2018404
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: <20231004220240.167175-2-peterx@redhat.com>
We are sending a migration event of MIGRATION_STATUS_SETUP at
qemu_start_incoming_migration but never actually setting the state.
This creates a window between qmp_migrate_incoming and
process_incoming_migration_co where the migration status is still
MIGRATION_STATUS_NONE. Calling query-migrate during this time will
return an empty response even though the incoming migration command
has already been issued.
Commit 7cf1fe6d68 ("migration: Add migration events on target side")
has added support to the 'events' capability to the incoming part of
migration, but chose to send the SETUP event without setting the
state. I'm assuming this was a mistake.
This introduces a change in behavior, any QMP client waiting for the
SETUP event will hang, unless it has previously enabled the 'events'
capability. Having the capability enabled is sufficient to continue to
receive the event.
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230712190742.22294-5-farosas@suse.de>
Extend the migration URI to support file:<filename>. This can be used for
any migration scenario that does not require a reverse path. It can be
used as an alternative to 'exec:cat > file' in minimized containers that
do not contain /bin/sh, and it is easier to use than the fd:<fdname> URI.
It can be used in HMP commands, and as a qemu command-line parameter.
For best performance, guest ram should be shared and x-ignore-shared
should be true, so guest pages are not written to the file, in which case
the guest may remain running. If ram is not so configured, then the user
is advised to stop the guest first. Otherwise, a busy guest may re-dirty
the same page, causing it to be appended to the file multiple times,
and the file may grow unboundedly. That issue is being addressed in the
"fixed-ram" patch series.
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Tested-by: Michael Galaxy <mgalaxy@akamai.com>
Reviewed-by: Michael Galaxy <mgalaxy@akamai.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <1694182931-61390-2-git-send-email-steven.sistare@oracle.com>
In the function qmp_migrate(), yank_unregister_instance() gets called
twice which isn't required. Hence, refactoring it so that it gets called
during the local_error cleanup.
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Acked-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Tejus GK <tejus.gk@nutanix.com>
Message-ID: <20230621130940.178659-3-tejus.gk@nutanix.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Now that the return path thread is allowed to finish during a paused
migration, we can move the cleanup of the QEMUFiles to the main
migration thread.
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20230918172822.19052-9-farosas@suse.de>
Replace the return path retry logic with finishing and restarting the
thread. This fixes a race when resuming the migration that leads to a
segfault.
Currently when doing postcopy we consider that an IO error on the
return path file could be due to a network intermittency. We then keep
the thread alive but have it do cleanup of the 'from_dst_file' and
wait on the 'postcopy_pause_rp' semaphore. When the user issues a
migrate resume, a new return path is opened and the thread is allowed
to continue.
There's a race condition in the above mechanism. It is possible for
the new return path file to be setup *before* the cleanup code in the
return path thread has had a chance to run, leading to the *new* file
being closed and the pointer set to NULL. When the thread is released
after the resume, it tries to dereference 'from_dst_file' and crashes:
Thread 7 "return path" received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7fffd1dbf700 (LWP 9611)]
0x00005555560e4893 in qemu_file_get_error_obj (f=0x0, errp=0x0) at ../migration/qemu-file.c:154
154 return f->last_error;
(gdb) bt
#0 0x00005555560e4893 in qemu_file_get_error_obj (f=0x0, errp=0x0) at ../migration/qemu-file.c:154
#1 0x00005555560e4983 in qemu_file_get_error (f=0x0) at ../migration/qemu-file.c:206
#2 0x0000555555b9a1df in source_return_path_thread (opaque=0x555556e06000) at ../migration/migration.c:1876
#3 0x000055555602e14f in qemu_thread_start (args=0x55555782e780) at ../util/qemu-thread-posix.c:541
#4 0x00007ffff38d76ea in start_thread (arg=0x7fffd1dbf700) at pthread_create.c:477
#5 0x00007ffff35efa6f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95
Here's the race (important bit is open_return_path happening before
migration_release_dst_files):
migration | qmp | return path
--------------------------+-----------------------------+---------------------------------
qmp_migrate_pause()
shutdown(ms->to_dst_file)
f->last_error = -EIO
migrate_detect_error()
postcopy_pause()
set_state(PAUSED)
wait(postcopy_pause_sem)
qmp_migrate(resume)
migrate_fd_connect()
resume = state == PAUSED
open_return_path <-- TOO SOON!
set_state(RECOVER)
post(postcopy_pause_sem)
(incoming closes to_src_file)
res = qemu_file_get_error(rp)
migration_release_dst_files()
ms->rp_state.from_dst_file = NULL
post(postcopy_pause_rp_sem)
postcopy_pause_return_path_thread()
wait(postcopy_pause_rp_sem)
rp = ms->rp_state.from_dst_file
goto retry
qemu_file_get_error(rp)
SIGSEGV
-------------------------------------------------------------------------------------------
We can keep the retry logic without having the thread alive and
waiting. The only piece of data used by it is the 'from_dst_file' and
it is only allowed to proceed after a migrate resume is issued and the
semaphore released at migrate_fd_connect().
Move the retry logic to outside the thread by waiting for the thread
to finish before pausing the migration.
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20230918172822.19052-8-farosas@suse.de>
We'll start calling the await_return_path_close_on_source() function
from other parts of the code, so move all of the related checks and
tracepoints into it.
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20230918172822.19052-7-farosas@suse.de>
This file is owned by the return path thread which is already doing
cleanup.
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20230918172822.19052-6-farosas@suse.de>
It's not safe to call qemu_file_shutdown() on the to_dst_file without
first checking for the file's presence under the lock. The cleanup of
this file happens at postcopy_pause() and migrate_fd_cleanup() which
are not necessarily running in the same thread as migrate_fd_cancel().
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20230918172822.19052-5-farosas@suse.de>
We cannot call qemu_file_shutdown() on the return path file without
taking the file lock. The return path thread could be running it's
cleanup code and have just cleared the from_dst_file pointer.
Checking ms->to_dst_file for errors could also race with
migrate_fd_cleanup() which clears the to_dst_file pointer.
Protect both accesses by taking the file lock.
This was caught by inspection, it should be rare, but the next patches
will start calling this code from other places, so let's do the
correct thing.
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20230918172822.19052-4-farosas@suse.de>
We don't need to set the rp_state.error right after a shutdown because
qemu_file_shutdown() always sets the QEMUFile error, so the return
path thread would have seen it and set the rp error itself.
Setting the error outside of the thread is also racy because the
thread could clear it after we set it.
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20230918172822.19052-3-farosas@suse.de>
We hit intermit CI issue on failing at migration-test over the unit test
preempt/plain:
qemu-system-x86_64: Unable to read from socket: Connection reset by peer
Memory content inconsistency at 5b43000 first_byte = bd last_byte = bc current = 4f hit_edge = 1
**
ERROR:../tests/qtest/migration-test.c:300:check_guests_ram: assertion failed: (bad == 0)
(test program exited with status code -6)
Fabiano debugged into it and found that the preempt thread can quit even
without receiving all the pages, which can cause guest not receiving all
the pages and corrupt the guest memory.
To make sure preempt thread finished receiving all the pages, we can rely
on the page_requested_count being zero because preempt channel will only
receive requested page faults. Note, not all the faulted pages are required
to be sent via the preempt channel/thread; imagine the case when a
requested page is just queued into the background main channel for
migration, the src qemu will just still send it via the background channel.
Here instead of spinning over reading the count, we add a condvar so the
main thread can wait on it if that unusual case happened, without burning
the cpu for no good reason, even if the duration is short; so even if we
spin in this rare case is probably fine. It's just better to not do so.
The condvar is only used when that special case is triggered. Some memory
ordering trick is needed to guarantee it from happening (against the
preempt thread status field), so the main thread will always get a kick
when that triggers correctly.
Closes: https://gitlab.com/qemu-project/qemu/-/issues/1886
Debugged-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20230918172822.19052-2-farosas@suse.de>
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>
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>
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>
There are places in migration.c where the migration is marked failed with
MIGRATION_STATUS_FAILED, but the failure reason is never updated. Hence
libvirt doesn't know why the migration failed when it queries for it.
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Tejus GK <tejus.gk@nutanix.com>
Message-ID: <20230621130940.178659-2-tejus.gk@nutanix.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Extend query-migrate to provide throttle time and estimated
ring full time with dirty-limit capability enabled, through which
we can observe if dirty limit take effect during live migration.
Signed-off-by: Hyman Huang(黄勇) <yong.huang@smartx.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-ID: <168733225273.5845.15871826788879741674-8@git.sr.ht>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Implement dirty-limit convergence algo for live migration,
which is kind of like auto-converge algo but using dirty-limit
instead of cpu throttle to make migration convergent.
Enable dirty page limit if dirty_rate_high_cnt greater than 2
when dirty-limit capability enabled, Disable dirty-limit if
migration be canceled.
Note that "set_vcpu_dirty_limit", "cancel_vcpu_dirty_limit"
commands are not allowed during dirty-limit live migration.
Signed-off-by: Hyman Huang(黄勇) <yong.huang@smartx.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <168733225273.5845.15871826788879741674-7@git.sr.ht>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
We're about to add more functions to this file so make it use the same
coding style as the rest of the code.
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
Message-Id: <20230607161306.31425-2-farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
The only migrate_fd_error() call sites are in "migration/migration.c",
which is also where we define migrate_fd_error(). Make the function
static, and remove its declaration from "migration/migration.h".
Cc: Juan Quintela <quintela@redhat.com> (maintainer:Migration)
Cc: Leonardo Bras <leobras@redhat.com> (reviewer:Migration)
Cc: Peter Xu <peterx@redhat.com> (reviewer:Migration)
Cc: qemu-trivial@nongnu.org
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2018404
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
It cuts back on those awkward, duplicated !(has_resume && resume)
expressions.
Cc: Juan Quintela <quintela@redhat.com> (maintainer:Migration)
Cc: Leonardo Bras <leobras@redhat.com> (reviewer:Migration)
Cc: Peter Xu <peterx@redhat.com> (reviewer:Migration)
Cc: qemu-trivial@nongnu.org
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2018404
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
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: 3710586caa ("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>
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>
Currently, it is only done when the iteration finishes successfully.
Not cleaning up the userfaultfd write protection can lead to
symptoms/issues such as the process hanging in memmove or GDB not
being able to attach.
Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
Message-Id: <20230526115908.196171-1-f.ebner@proxmox.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
1. Otherwise failed migration just drops guest-panicked state, which is
not good for management software.
2. We do keep different paused states like guest-panicked during
migration with help of global_state state.
3. We do restore running state on source when migration is cancelled or
failed.
4. "postmigrate" state is documented as "guest is paused following a
successful 'migrate'", so originally it's only for successful path
and we never documented current behavior.
Let's restore paused states like guest-panicked in case of cancel or
fail too. Allow same transitions like for inmigrate state.
This commit changes the behavior that was introduced by commit
42da5550d6 "migration: set state to post-migrate on failure" and
provides a bit different fix on related
https://bugzilla.redhat.com/show_bug.cgi?id=1355683
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20230517123752.21615-6-vsementsov@yandex-team.ru>
Signed-off-by: Juan Quintela <quintela@redhat.com>
No logic change here, only refactoring. That's a preparation for next
commit where we finally restore the stopped vm state on migration
failure or cancellation.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20230517123752.21615-5-vsementsov@yandex-team.ru>
Signed-off-by: Juan Quintela <quintela@redhat.com>
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>
Once there rename it to migration_transferred_bytes() and pass a
QEMUFile instead of a migration object.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20230515195709.63843-7-quintela@redhat.com>
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>
Define and use RATE_LIMIT_DISABLED instead.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Message-Id: <20230515195709.63843-2-quintela@redhat.com>
Let's make better public interface for COLO: instead of
colo_process_incoming_thread and not trivial logic around creating the
thread let's make simple colo_incoming_co(), hiding implementation from
generic code.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20230515130640.46035-4-vsementsov@yandex-team.ru>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Originally, migration_incoming_co was introduced by
25d0c16f62
"migration: Switch to COLO process after finishing loadvm"
to be able to enter from COLO code to one specific yield point, added
by 25d0c16f62.
Later in 923709896b
"migration: poll the cm event for destination qemu"
we reused this variable to wake the migration incoming coroutine from
RDMA code.
That was doubtful idea. Entering coroutines is a very fragile thing:
you should be absolutely sure which yield point you are going to enter.
I don't know how much is it safe to enter during qemu_loadvm_state()
which I think what RDMA want to do. But for sure RDMA shouldn't enter
the special COLO-related yield-point. As well, COLO code doesn't want
to enter during qemu_loadvm_state(), it want to enter it's own specific
yield-point.
As well, when in 8e48ac9586
"COLO: Add block replication into colo process" we added
bdrv_invalidate_cache_all() call (now it's called activate_all())
it became possible to enter the migration incoming coroutine during
that call which is wrong too.
So, let't make these things separate and disjoint: loadvm_co for RDMA,
non-NULL during qemu_loadvm_state(), and colo_incoming_co for COLO,
non-NULL only around specific yield.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20230515130640.46035-3-vsementsov@yandex-team.ru>
Signed-off-by: Juan Quintela <quintela@redhat.com>
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>
That the implementation does the check every 100 milliseconds is an
implementation detail that shouldn't be seen on the interfaz.
Notice that all callers of qemu_file_set_rate_limit() used the
division or pass 0, so this change is a NOP.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20230508130909.65420-4-quintela@redhat.com>
And it is the best way to not have rate_limit.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20230508130909.65420-2-quintela@redhat.com>
We generally require same set of capabilities on source and target.
Let's require x-colo capability to use COLO on target.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Lukas Straub <lukasstraub2@web.de>
Reviewed-by: Zhang Chen <chen.zhang@intel.com>
Message-Id: <20230428194928.1426370-11-vsementsov@yandex-team.ru>
Signed-off-by: Juan Quintela <quintela@redhat.com>
COLO is not listed as running state in migrate_is_running(), so, it's
theoretically possible to disable colo capability in COLO state and the
unexpected error in migration_iteration_finish() is reachable.
Let's disallow that in qmp_migrate_set_capabilities. Than the error
becomes absolutely unreachable: we can get into COLO state only with
enabled capability and can't disable it while we are in COLO state. So
substitute the error by simple assertion.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Message-Id: <20230428194928.1426370-10-vsementsov@yandex-team.ru>
Signed-off-by: Juan Quintela <quintela@redhat.com>
have_colo_incoming_thread variable is unused. colo_incoming_thread can
be local.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Zhang Chen <chen.zhang@intel.com>
Message-Id: <20230428194928.1426370-6-vsementsov@yandex-team.ru>
Signed-off-by: Juan Quintela <quintela@redhat.com>
We don't allow to use x-colo capability when replication is not
configured. So, no reason to build COLO when replication is disabled,
it's unusable in this case.
Note also that the check in migrate_caps_check() is not the only
restriction: some functions in migration/colo.c will just abort if
called with not defined CONFIG_REPLICATION, for example:
migration_iteration_finish()
case MIGRATION_STATUS_COLO:
migrate_start_colo_process()
colo_process_checkpoint()
abort()
It could probably make sense to have possibility to enable COLO without
REPLICATION, but this requires deeper audit of colo & replication code,
which may be done later if needed.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Acked-by: Dr. David Alan Gilbert <dave@treblig.org>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20230428194928.1426370-4-vsementsov@yandex-team.ru>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Commit fe904ea824 added a fail_inactivate label, which tries to
reactivate disks on the source after a failure while s->state ==
MIGRATION_STATUS_ACTIVE, but didn't actually use the label if
qemu_savevm_state_complete_precopy() failed. This failure to
reactivate is also present in commit 6039dd5b1c (also covering the new
s->state == MIGRATION_STATUS_DEVICE state) and 403d18ae (ensuring
s->block_inactive is set more reliably).
Consolidate the two labels back into one - no matter HOW migration is
failed, if there is any chance we can reach vm_start() after having
attempted inactivation, it is essential that we have tried to restart
disks before then. This also makes the cleanup more like
migrate_fd_cancel().
Suggested-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20230502205212.134680-1-eblake@redhat.com>
Acked-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This fixes compress with colo.
Signed-off-by: Lukas Straub <lukasstraub2@web.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
