Commit Graph

414 Commits

Author SHA1 Message Date
Fabiano Rosas
7f5b50a401 migration/qemu-file: add utility methods for working with seekable channels
Add utility methods that will be needed when implementing 'mapped-ram'
migration capability.

Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: "Daniel P. Berrangé" <berrange@redhat.com>
Link: https://lore.kernel.org/r/20240229153017.2221-7-farosas@suse.de
Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-01 15:42:04 +08:00
Steve Sistare
9867d4ddd0 migration: stop vm for cpr
When migration for cpr is initiated, stop the vm and set state
RUN_STATE_FINISH_MIGRATE before ram is saved.  This eliminates the
possibility of ram and device state being out of sync, and guarantees
that a guest in the suspended state remains suspended, because qmp_cont
rejects a cont command in the RUN_STATE_FINISH_MIGRATE state.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/1708622920-68779-11-git-send-email-steven.sistare@oracle.com
Signed-off-by: Peter Xu <peterx@redhat.com>
2024-02-28 11:31:28 +08:00
Steve Sistare
4af667f87c migration: notifier error checking
Check the status returned by migration notifiers for event type
MIG_EVENT_PRECOPY_SETUP, and report errors.  None of the notifiers
return an error status at this time.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/1708622920-68779-10-git-send-email-steven.sistare@oracle.com
Signed-off-by: Peter Xu <peterx@redhat.com>
2024-02-28 11:31:28 +08:00
Steve Sistare
6835f5a1bc migration: per-mode notifiers
Keep a separate list of migration notifiers for each migration mode.

Suggested-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/1708622920-68779-8-git-send-email-steven.sistare@oracle.com
Signed-off-by: Peter Xu <peterx@redhat.com>
2024-02-28 11:31:28 +08:00
Steve Sistare
5663dd3f1a migration: MigrationNotifyFunc
Define MigrationNotifyFunc to improve type safety and simplify migration
notifiers.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/1708622920-68779-7-git-send-email-steven.sistare@oracle.com
Signed-off-by: Peter Xu <peterx@redhat.com>
2024-02-28 11:31:28 +08:00
Steve Sistare
c763a23e41 migration: remove postcopy_after_devices
postcopy_after_devices and migration_in_postcopy_after_devices are no
longer used, so delete them.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/1708622920-68779-6-git-send-email-steven.sistare@oracle.com
Signed-off-by: Peter Xu <peterx@redhat.com>
2024-02-28 11:31:28 +08:00
Steve Sistare
9d9babf78d migration: MigrationEvent for notifiers
Passing MigrationState to notifiers is unsound because they could access
unstable migration state internals or even modify the state.  Instead, pass
the minimal info needed in a new MigrationEvent struct, which could be
extended in the future if needed.

Suggested-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/1708622920-68779-5-git-send-email-steven.sistare@oracle.com
Signed-off-by: Peter Xu <peterx@redhat.com>
2024-02-28 11:31:28 +08:00
Steve Sistare
3e7757301c migration: convert to NotifierWithReturn
Change all migration notifiers to type NotifierWithReturn, so notifiers
can return an error status in a future patch.  For now, pass NULL for the
notifier error parameter, and do not check the return value.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/1708622920-68779-4-git-send-email-steven.sistare@oracle.com
[peterx: dropped unexpected update to roms/seabios-hppa]
Signed-off-by: Peter Xu <peterx@redhat.com>
2024-02-28 11:31:28 +08:00
Steve Sistare
d91f33c72e migration: remove error from notifier data
Remove the error object from opaque data passed to notifiers.
Use the new error parameter passed to the notifier instead.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/1708622920-68779-3-git-send-email-steven.sistare@oracle.com
Signed-off-by: Peter Xu <peterx@redhat.com>
2024-02-28 11:31:28 +08:00
Stefan Hajnoczi
a4a411fbaf Replace "iothread lock" with "BQL" in comments
The term "iothread lock" is obsolete. The APIs use Big QEMU Lock (BQL)
in their names. Update the code comments to use "BQL" instead of
"iothread lock".

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Paul Durrant <paul@xen.org>
Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Message-id: 20240102153529.486531-5-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2024-01-08 10:45:43 -05:00
Peter Maydell
c8193acc07 migration 1st pull for 9.0
- We lost Juan and Leo in the maintainers file
 - Steven's suspend state fix
 - Steven's fix for coverity on migrate_mode
 - Avihai's migration cleanup series
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Merge tag 'migration-20240104-pull-request' of https://gitlab.com/peterx/qemu into staging

migration 1st pull for 9.0

- We lost Juan and Leo in the maintainers file
- Steven's suspend state fix
- Steven's fix for coverity on migrate_mode
- Avihai's migration cleanup series

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* tag 'migration-20240104-pull-request' of https://gitlab.com/peterx/qemu: (26 commits)
  migration: fix coverity migrate_mode finding
  migration/multifd: Remove unnecessary usage of local Error
  migration: Remove unnecessary usage of local Error
  migration: Fix migration_channel_read_peek() error path
  migration/multifd: Remove error_setg() in migration_ioc_process_incoming()
  migration/multifd: Fix leaking of Error in TLS error flow
  migration/multifd: Simplify multifd_channel_connect() if else statement
  migration/multifd: Fix error message in multifd_recv_initial_packet()
  migration: Remove errp parameter in migration_fd_process_incoming()
  migration: Refactor migration_incoming_setup()
  migration: Remove nulling of hostname in migrate_init()
  migration: Remove migrate_max_downtime() declaration
  tests/qtest: postcopy migration with suspend
  tests/qtest: precopy migration with suspend
  tests/qtest: option to suspend during migration
  tests/qtest: migration events
  migration: preserve suspended for bg_migration
  migration: preserve suspended for snapshot
  migration: preserve suspended runstate
  migration: propagate suspended runstate
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2024-01-05 13:35:25 +00:00
Steve Sistare
58b105703e migration: preserve suspended for snapshot
Restoring a snapshot can break a suspended guest.  Snapshots suffer from
the same suspended-state issues that affect live migration, plus they must
handle an additional problematic scenario, which is that a running vm must
remain running if it loads a suspended snapshot.

To save, the existing vm_stop call now completely stops the suspended
state.  Finish with vm_resume to leave the vm in the state it had prior
to the save, correctly restoring the suspended state.

To load, if the snapshot is not suspended, then vm_stop + vm_resume
correctly handles all states, and leaves the vm in the state it had prior
to the load.  However, if the snapshot is suspended, restoration is
trickier.  First, call vm_resume to restore the state to suspended so the
current state matches the saved state.  Then, if the pre-load state is
running, call wakeup to resume running.

Prior to these changes, the vm_stop to RUN_STATE_SAVE_VM and
RUN_STATE_RESTORE_VM did not change runstate if the current state was
suspended, but now it does, so allow these transitions.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/1704312341-66640-8-git-send-email-steven.sistare@oracle.com
Signed-off-by: Peter Xu <peterx@redhat.com>
2024-01-04 09:52:42 +08:00
Richard Henderson
2027001919 migration: Make VMStateDescription.subsections const
Allow the array of pointers to itself be const.
Propagate this through the copies of this field.

Tested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20231221031652.119827-2-richard.henderson@linaro.org>
2023-12-29 11:17:30 +11:00
Steve Sistare
fa3673e497 migration: per-mode blockers
Extend the blocker interface so that a blocker can be registered for
one or more migration modes.  The existing interfaces register a
blocker for all modes, and the new interfaces take a varargs list
of modes.

Internally, maintain a separate blocker list per mode.  The same Error
object may be added to multiple lists.  When a block is deleted, it is
removed from every list, and the Error is freed.

No functional change until a new mode is added.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <1698263069-406971-3-git-send-email-steven.sistare@oracle.com>
2023-11-01 16:13:59 +01:00
Steve Sistare
eea1e5c9d6 migration: mode parameter
Create a mode migration parameter that can be used to select alternate
migration algorithms.  The default mode is normal, representing the
current migration algorithm, and does not need to be explicitly set.

No functional change until a new mode is added, except that the mode is
shown by the 'info migrate' command.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <1698263069-406971-2-git-send-email-steven.sistare@oracle.com>
2023-11-01 16:13:58 +01:00
Juan Quintela
485fb95546 migration: Hack to maintain backwards compatibility for ppc
Current code does:
- register pre_2_10_vmstate_dummy_icp with "icp/server" and instance
  dependinfg on cpu number
- for newer machines, it register vmstate_icp with "icp/server" name
  and instance 0
- now it unregisters "icp/server" for the 1st instance.

This is wrong at many levels:
- we shouldn't have two VMSTATEDescriptions with the same name
- In case this is the only solution that we can came with, it needs to
  be:
  * register pre_2_10_vmstate_dummy_icp
  * unregister pre_2_10_vmstate_dummy_icp
  * register real vmstate_icp

Created vmstate_replace_hack_for_ppc() with warnings left and right
that it is a hack.

CC: Cedric Le Goater <clg@kaod.org>
CC: Daniel Henrique Barboza <danielhb413@gmail.com>
CC: David Gibson <david@gibson.dropbear.id.au>
CC: Greg Kurz <groug@kaod.org>

Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231020090731.28701-8-quintela@redhat.com>
2023-11-01 16:13:58 +01:00
Juan Quintela
71daf640d9 migration: Create vmstate_register_any()
We have lots of cases where we are using an instance_id==0 when we
should be using VMSTATE_INSTANCE_ID_ANY (-1).  Basically everything
that can have more than one needs to have a proper instance_id or -1
and the system will take one for it.

vmstate_register_any(): We register with -1.

Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231020090731.28701-2-quintela@redhat.com>
2023-11-01 16:13:58 +01:00
Marc-André Lureau
4d8bdc2ae0 migration: rename vmstate_save_needed->vmstate_section_needed
The function is used on save at this point. The following commits will
use it on load.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231024084043.2926316-5-marcandre.lureau@redhat.com>
2023-10-30 17:44:03 +01:00
Steve Sistare
d9cda21303 migration: simplify notifiers
Pass the callback function to add_migration_state_change_notifier so
that migration can initialize the notifier on add and clear it on
delete, which simplifies the call sites.  Shorten the function names
so the extra arg can be added more legibly.  Hide the global notifier
list in a new function migration_call_notifiers, and make it externally
visible so future live update code can call it.

No functional change.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Tested-by: Michael Galaxy <mgalaxy@akamai.com>
Reviewed-by: Michael Galaxy <mgalaxy@akamai.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <1686148954-250144-1-git-send-email-steven.sistare@oracle.com>
2023-10-20 08:51:41 +02:00
Steve Sistare
c8a7fc5179 migration: simplify blockers
Modify migrate_add_blocker and migrate_del_blocker to take an Error **
reason.  This allows migration to own the Error object, so that if
an error occurs in migrate_add_blocker, migration code can free the Error
and clear the client handle, simplifying client code.  It also simplifies
the migrate_del_blocker call site.

In addition, this is a pre-requisite for a proposed future patch that would
add a mode argument to migration requests to support live update, and
maintain a list of blockers for each mode.  A blocker may apply to a single
mode or to multiple modes, and passing Error** will allow one Error object
to be registered for multiple modes.

No functional change.

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: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <1697634216-84215-1-git-send-email-steven.sistare@oracle.com>
2023-10-20 08:51:41 +02:00
Fiona Ebner
930e239d11 migration: hold the BQL during setup
This is intended to be a semantic revert of commit 9b09503752
("migration: run setup callbacks out of big lock"). There have been so
many changes since that commit (e.g. a new setup callback
dirty_bitmap_save_setup() that also needs to be adapted now), it's
easier to do the revert manually.

For snapshots, the bdrv_writev_vmstate() function is used during setup
(in QIOChannelBlock backing the QEMUFile), but not holding the BQL
while calling it could lead to an assertion failure. To understand
how, first note the following:

1. Generated coroutine wrappers for block layer functions spawn the
coroutine and use AIO_WAIT_WHILE()/aio_poll() to wait for it.
2. If the host OS switches threads at an inconvenient time, it can
happen that a bottom half scheduled for the main thread's AioContext
is executed as part of a vCPU thread's aio_poll().

An example leading to the assertion failure is as follows:

main thread:
1. A snapshot-save QMP command gets issued.
2. snapshot_save_job_bh() is scheduled.

vCPU thread:
3. aio_poll() for the main thread's AioContext is called (e.g. when
the guest writes to a pflash device, as part of blk_pwrite which is a
generated coroutine wrapper).
4. snapshot_save_job_bh() is executed as part of aio_poll().
3. qemu_savevm_state() is called.
4. qemu_mutex_unlock_iothread() is called. Now
qemu_get_current_aio_context() returns 0x0.
5. bdrv_writev_vmstate() is executed during the usual savevm setup
via qemu_fflush(). But this function is a generated coroutine wrapper,
so it uses AIO_WAIT_WHILE. There, the assertion
assert(qemu_get_current_aio_context() == qemu_get_aio_context());
will fail.

To fix it, ensure that the BQL is held during setup. While it would
only be needed for snapshots, adapting migration too avoids additional
logic for conditional locking/unlocking in the setup callbacks.
Writing the header could (in theory) also trigger qemu_fflush() and
thus bdrv_writev_vmstate(), so the locked section also covers the
qemu_savevm_state_header() call, even for migration for consistency.

The section around multifd_send_sync_main() needs to be unlocked to
avoid a deadlock. In particular, the multifd_save_setup() function calls
socket_send_channel_create() using multifd_new_send_channel_async() as a
callback and then waits for the callback to signal via the
channels_ready semaphore. The connection happens via
qio_task_run_in_thread(), but the callback is only executed via
qio_task_thread_result() which is scheduled for the main event loop.
Without unlocking the section, the main thread would never get to
process the task result and the callback meaning there would be no
signal via the channels_ready semaphore.

The comment in ram_init_bitmaps() was introduced by 4987783400
("migration: fix incorrect memory_global_dirty_log_start outside BQL")
and is removed, because it referred to the qemu_mutex_lock_iothread()
call.

Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231013105839.415989-1-f.ebner@proxmox.com>
2023-10-17 09:25:13 +02:00
Tejus GK
969298f9d7 migration/vmstate: Introduce vmstate_save_state_with_err
Currently, a few code paths exist in the function vmstate_save_state_v,
which ultimately leads to a migration failure. However, an update in the
current MigrationState for the error description is never done.

vmstate.c somehow doesn't seem to allow	the use	of migrate_set_error due
to some	dependencies for unit tests. Hence, this patch introduces a new
function vmstate_save_state_with_err, which will eventually propagate
the error message to savevm.c where a migrate_set_error	call can be
eventually done.

Acked-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Tejus GK <tejus.gk@nutanix.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231003065538.244752-2-tejus.gk@nutanix.com>
2023-10-04 10:54:40 +02:00
Stefan Hajnoczi
9ef497755a vfio queue:
* Small downtime optimisation for VFIO migration
 * P2P support for VFIO migration
 * Introduction of a save_prepare() handler to fail VFIO migration
 * Fix on DMA logging ranges calculation for OVMF enabling dynamic window
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Merge tag 'pull-vfio-20230911' of https://github.com/legoater/qemu into staging

vfio queue:

* Small downtime optimisation for VFIO migration
* P2P support for VFIO migration
* Introduction of a save_prepare() handler to fail VFIO migration
* Fix on DMA logging ranges calculation for OVMF enabling dynamic window

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# gpg: Signature made Mon 11 Sep 2023 02:54:12 EDT
# gpg:                using RSA key A0F66548F04895EBFE6B0B6051A343C7CFFBECA1
# gpg: Good signature from "Cédric Le Goater <clg@redhat.com>" [unknown]
# gpg:                 aka "Cédric Le Goater <clg@kaod.org>" [unknown]
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: A0F6 6548 F048 95EB FE6B  0B60 51A3 43C7 CFFB ECA1

* tag 'pull-vfio-20230911' of https://github.com/legoater/qemu:
  vfio/common: Separate vfio-pci ranges
  vfio/migration: Block VFIO migration with background snapshot
  vfio/migration: Block VFIO migration with postcopy migration
  migration: Add .save_prepare() handler to struct SaveVMHandlers
  migration: Move more initializations to migrate_init()
  vfio/migration: Fail adding device with enable-migration=on and existing blocker
  migration: Add migration prefix to functions in target.c
  vfio/migration: Allow migration of multiple P2P supporting devices
  vfio/migration: Add P2P support for VFIO migration
  vfio/migration: Refactor PRE_COPY and RUNNING state checks
  qdev: Add qdev_add_vm_change_state_handler_full()
  sysemu: Add prepare callback to struct VMChangeStateEntry
  vfio/migration: Move from STOP_COPY to STOP in vfio_save_cleanup()

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2023-09-11 09:13:08 -04:00
Avihai Horon
08fc4cb517 migration: Add .save_prepare() handler to struct SaveVMHandlers
Add a new .save_prepare() handler to struct SaveVMHandlers. This handler
is called early, even before migration starts, and can be used by
devices to perform early checks.

Refactor migrate_init() to be able to return errors and call
.save_prepare() from there.

Suggested-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2023-09-11 08:34:06 +02:00
Kevin Wolf
8686a689e5 vmstate: Mark VMStateInfo.get/put() coroutine_mixed_fn
Migration code can run both in coroutine context (the usual case) and
non-coroutine context (at least savevm/loadvm for snapshots). This also
affects the VMState callbacks, and devices must consider this. Change
the callback definition in VMStateInfo to be explicit about it.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20230905145002.46391-2-kwolf@redhat.com>
Acked-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-09-08 17:03:09 +02:00
David Hildenbrand
f161c88a03 migration/ram: Expose ramblock_is_ignored() as migrate_ram_is_ignored()
virtio-mem wants to know whether it should not mess with the RAMBlock
content (e.g., discard RAM, preallocate memory) on incoming migration.

So let's expose that function as migrate_ram_is_ignored() in
migration/misc.h

Message-ID: <20230706075612.67404-4-david@redhat.com>
Acked-by: Peter Xu <peterx@redhat.com>
Tested-by: Mario Casquero <mcasquer@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
2023-07-12 09:25:37 +02:00
Alex Bennée
6caf1571a9 include/migration: mark vmstate_register() as a legacy function
Mention that QOM-ified devices already have support for registering
the description.

Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20230630180423.558337-24-alex.bennee@linaro.org>
2023-07-03 12:52:11 +01:00
Avihai Horon
1b4adb10f8 migration: Implement switchover ack logic
Implement switchover ack logic. This prevents the source from stopping
the VM and completing the migration until an ACK is received from the
destination that it's OK to do so.

To achieve this, a new SaveVMHandlers handler switchover_ack_needed()
and a new return path message MIG_RP_MSG_SWITCHOVER_ACK are added.

The switchover_ack_needed() handler is called during migration setup in
the destination to check if switchover ack is used by the migrated
device.

When switchover is approved by all migrated devices in the destination
that support this capability, the MIG_RP_MSG_SWITCHOVER_ACK return path
message is sent to the source to notify it that it's OK to do
switchover.

Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Tested-by: YangHang Liu <yanghliu@redhat.com>
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2023-06-30 06:02:51 +02:00
Vladimir Sementsov-Ogievskiy
c33f1829f8 migration: never fail in global_state_store()
Actually global_state_store() can never fail. Let's get rid of extra
error paths.

To make things clear, use new runstate_get() and use same approach for
global_state_store() and global_state_store_running().

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20230517123752.21615-3-vsementsov@yandex-team.ru>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-06-02 01:03:19 +02:00
Juan Quintela
e1fde0e038 migration: Move rate_limit_max and rate_limit_used to migration_stats
These way we can make them atomic and use this functions from any
place.  I also moved all functions that use rate_limit to
migration-stats.

Functions got renamed, they are not qemu_file anymore.

qemu_file_rate_limit -> migration_rate_exceeded
qemu_file_set_rate_limit -> migration_rate_set
qemu_file_get_rate_limit -> migration_rate_get
qemu_file_reset_rate_limit -> migration_rate_reset
qemu_file_acct_rate_limit -> migration_rate_account.

Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20230515195709.63843-6-quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-05-18 18:40:51 +02:00
Vladimir Sementsov-Ogievskiy
d0a14a2ba0 migration: process_incoming_migration_co(): move colo part to colo
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>
2023-05-18 18:40:51 +02:00
Vladimir Sementsov-Ogievskiy
4332ffcd7b colo: make colo_checkpoint_notify static and provide simpler API
colo_checkpoint_notify() is mostly used in colo.c. Outside we use it
once when x-checkpoint-delay migration parameter is set. So, let's
simplify the external API to only that function - notify COLO that
parameter was set. This make external API more robust and hides
implementation details from external callers. Also this helps us to
make COLO module optional in further patch (i.e. we are going to add
possibility not build the COLO module).

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: <20230428194928.1426370-3-vsementsov@yandex-team.ru>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-05-10 18:48:11 +02:00
Juan Quintela
c938157713 migration: move migration_global_dump() to migration-hmp-cmds.c
It is only used there, so we can make it static.
Once there, remove spice.h that it is not used.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

---

fix David Edmonson ui/qemu-spice.h unintended removal
2023-04-24 15:01:46 +02:00
Paolo Bonzini
394b9407e4 migration: mark mixed functions that can suspend
There should be no paths from a coroutine_fn to aio_poll, however in
practice coroutine_mixed_fn will call aio_poll in the !qemu_in_coroutine()
path.  By marking mixed functions, we can track accurately the call paths
that execute entirely in coroutine context, and find more missing
coroutine_fn markers.  This results in more accurate checks that
coroutine code does not end up blocking.

If the marking were extended transitively to all functions that call
these ones, static analysis could be done much more efficiently.
However, this is a start and makes it possible to use vrc's path-based
searches to find potential bugs where coroutine_fns call blocking functions.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-04-20 11:17:35 +02:00
Juan Quintela
24beea4efe migration: Rename res_{postcopy,precopy}_only
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>
2023-02-15 20:04:30 +01:00
Juan Quintela
24f254ed79 migration: Remove unused res_compatible
Nothing assigns to it after previous commit.

Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-15 20:04:30 +01:00
Dr. David Alan Gilbert
89c5684891 migration: Add canary to VMSTATE_END_OF_LIST
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>
2023-02-06 19:22:56 +01:00
David Hildenbrand
80fe315c38 migration/ram: Factor out check for advised postcopy
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>
2023-02-06 19:22:56 +01:00
David Hildenbrand
508f7988fd migration/vmstate: Introduce VMSTATE_WITH_TMP_TEST() and VMSTATE_BITMAP_TEST()
We'll make use of both next in the context of virtio-mem.

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>S
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-06 19:22:56 +01:00
David Hildenbrand
62f42625d4 migration/savevm: Allow immutable device state to be migrated early (i.e., 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>
2023-02-06 19:22:56 +01:00
Juan Quintela
fd70385d38 migration: Remove unused threshold_size parameter
Until previous commit, save_live_pending() was used for ram.  Now with
the split into state_pending_estimate() and state_pending_exact() it
is not needed anymore, so remove them.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2023-02-06 19:22:56 +01:00
Juan Quintela
c8df4a7aef 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.

The only "device" that implements different functions for _estimate()
and _exact() is ram.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2023-02-06 19:22:56 +01:00
Juan Quintela
255dc7af7e migration: No save_live_pending() method uses the QEMUFile parameter
So remove it everywhere.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2023-02-06 19:22:56 +01:00
Peter Maydell
1862198702 migration: Remove load_state_old and minimum_version_id_old
There are no longer any VMStateDescription structs in the tree which
use the load_state_old support for custom handling of incoming
migration from very old QEMU.  Remove the mechanism entirely.

This includes removing one stray useless setting of
minimum_version_id_old in a VMStateDescription with no load_state_old
function, which crept in after the global weeding-out of them in
commit 17e3134061.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20220215175705.3846411-1-peter.maydell@linaro.org>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Francisco Iglesias <francisco.iglesias@xilinx.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2022-03-02 18:20:45 +00:00
Rao, Lei
795969ab1f Fixed a QEMU hang when guest poweroff in COLO mode
When the PVM guest poweroff, the COLO thread may wait a semaphore
in colo_process_checkpoint().So, we should wake up the COLO thread
before migration shutdown.

Signed-off-by: Lei Rao <lei.rao@intel.com>
Reviewed-by: Zhang Chen <chen.zhang@intel.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2021-12-15 10:31:42 +01:00
Peter Xu
60fd680193 migration: Add migrate_add_blocker_internal()
An internal version that removes -only-migratable implications.  It can be used
for temporary migration blockers like dump-guest-memory.

Reviewed-by: Marc-André Lureau <marcandre.lureau@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>
2021-11-01 22:56:44 +01:00
David Hildenbrand
0fd7616e0f vfio: Support for RamDiscardManager in the vIOMMU case
vIOMMU support works already with RamDiscardManager as long as guests only
map populated memory. Both, populated and discarded memory is mapped
into &address_space_memory, where vfio_get_xlat_addr() will find that
memory, to create the vfio mapping.

Sane guests will never map discarded memory (e.g., unplugged memory
blocks in virtio-mem) into an IOMMU - or keep it mapped into an IOMMU while
memory is getting discarded. However, there are two cases where a malicious
guests could trigger pinning of more memory than intended.

One case is easy to handle: the guest trying to map discarded memory
into an IOMMU.

The other case is harder to handle: the guest keeping memory mapped in
the IOMMU while it is getting discarded. We would have to walk over all
mappings when discarding memory and identify if any mapping would be a
violation. Let's keep it simple for now and print a warning, indicating
that setting RLIMIT_MEMLOCK can mitigate such attacks.

We have to take care of incoming migration: at the point the
IOMMUs get restored and start creating mappings in vfio, RamDiscardManager
implementations might not be back up and running yet: let's add runstate
priorities to enforce the order when restoring.

Acked-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Auger Eric <eric.auger@redhat.com>
Cc: Wei Yang <richard.weiyang@linux.alibaba.com>
Cc: teawater <teawaterz@linux.alibaba.com>
Cc: Marek Kedzierski <mkedzier@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20210413095531.25603-10-david@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
2021-07-08 15:54:45 -04:00
Philippe Mathieu-Daudé
feece4d070 cpu: Move CPUClass::vmsd to SysemuCPUOps
Migration is specific to system emulation.

- Move the CPUClass::vmsd field to SysemuCPUOps,
- restrict VMSTATE_CPU() macro to sysemu,
- vmstate_dummy is now unused, remove it.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210517105140.1062037-16-f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2021-05-26 15:33:59 -07:00
David Hildenbrand
1a37352277 migrate/ram: remove "ram_bulk_stage" and "fpo_enabled"
The bulk stage is kind of weird: migration_bitmap_find_dirty() will
indicate a dirty page, however, ram_save_host_page() will never save it, as
migration_bitmap_clear_dirty() detects that it is not dirty.

We already fill the bitmap in ram_list_init_bitmaps() with ones, marking
everything dirty - it didn't used to be that way, which is why we needed
an explicit first bulk stage.

Let's simplify: make the bitmap the single source of thuth. Explicitly
handle the "xbzrle_enabled after first round" case.

Regarding XBZRLE (implicitly handled via "ram_bulk_stage = false" right
now), there is now a slight change in behavior:
- Colo: When starting, it will be disabled (was implicitly enabled)
  until the first round actually finishes.
- Free page hinting: When starting, XBZRLE will be disabled (was implicitly
  enabled) until the first round actually finished.
- Snapshots: When starting, XBZRLE will be disabled. We essentially only
  do a single run, so I guess it will never actually get disabled.

Postcopy seems to indirectly disable it in ram_save_page(), so there
shouldn't be really any change.

Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Juan Quintela <quintela@redhat.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Andrey Gruzdev <andrey.gruzdev@virtuozzo.com>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20210216105039.40680-1-david@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-05-13 18:21:13 +01:00
Andrey Gruzdev
1a8e44a89f migration: Inhibit virtio-balloon for the duration of background snapshot
The same thing as for incoming postcopy - we cannot deal with concurrent
RAM discards when using background snapshot feature in outgoing migration.

Fixes: 8518278a6a (migration: implementation
  of background snapshot thread)
Signed-off-by: Andrey Gruzdev <andrey.gruzdev@virtuozzo.com>
Reported-by: David Hildenbrand <david@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Message-Id: <20210401092226.102804-3-andrey.gruzdev@virtuozzo.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-04-06 18:56:01 +01:00