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>
This is the big patch that removes
aio_context_acquire()/aio_context_release() from the block layer and
affected block layer users.
There isn't a clean way to split this patch and the reviewers are likely
the same group of people, so I decided to do it in one patch.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Paul Durrant <paul@xen.org>
Message-ID: <20231205182011.1976568-7-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
qemu_uuid_unparse() includes a trailing NUL when writing the uuid
string and the buffer size should be UUID_FMT_LEN + 1 bytes. Add a
define for this size and use it where required.
Cc: Fam Zheng <fam@euphon.net>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: "Denis V. Lunev" <den@openvz.org>
Signed-off-by: Cédric Le Goater <clg@redhat.com>
This patch is inspired by Joao Martin's patch here:
https://lore.kernel.org/r/20230926161841.98464-1-joao.m.martins@oracle.com
Add tracepoints for major downtime checkpoints on both src and dst. They
share the same tracepoint with a string showing its stage.
Besides the checkpoints in the previous patch, this patch also added
destination checkpoints.
On src, we have these checkpoints added:
- src-downtime-start: right before vm stops on src
- src-vm-stopped: after vm is fully stopped
- src-iterable-saved: after all iterables saved (END sections)
- src-non-iterable-saved: after all non-iterable saved (FULL sections)
- src-downtime-stop: migration fully completed
On dst, we have these checkpoints added:
- dst-precopy-loadvm-completes: after loadvm all done for precopy
- dst-precopy-bh-*: record BH steps to resume VM for precopy
- dst-postcopy-bh-*: record BH steps to resume VM for postcopy
On dst side, we don't have a good way to trace total time consumed by
iterable or non-iterable for now. We can mark it by 1st time receiving a
FULL / END section, but rather than that let's just rely on the other
tracepoints added for vmstates to back up the information.
With this patch, one can enable "vmstate_downtime*" tracepoints and it'll
enable all tracepoints for downtime measurements necessary.
Drop loadvm_postcopy_handle_run_bh() tracepoint alongside, because they
service the same purpose, which was only for postcopy. We then have
unified prefix for all downtime relevant tracepoints.
Co-developed-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231030163346.765724-6-peterx@redhat.com>
We have a bunch of savevm_section* tracepoints, they're good to analyze
migration stream, but not always suitable if someone would like to analyze
the migration downtime. Two major problems:
- savevm_section* tracepoints are dumping all sections, we only care
about the sections that contribute to the downtime
- They don't have an identifier to show the type of sections, so no way
to filter downtime information either easily.
We can add type into the tracepoints, but instead of doing so, this patch
kept them untouched, instead of adding a bunch of downtime specific
tracepoints, so one can enable "vmstate_downtime*" tracepoints and get a
full picture of how the downtime is distributed across iterative and
non-iterative vmstate save/load.
Note that here both save() and load() need to be traced, because both of
them may contribute to the downtime. The contribution is not a simple "add
them together", though: consider when the src is doing a save() of device1
while the dest can be load()ing for device2, so they can happen
concurrently.
Tracking both sides make sense because device load() and save() can be
imbalanced, one device can save() super fast, but load() super slow, vice
versa. We can't figure that out without tracing both.
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231030163346.765724-4-peterx@redhat.com>
Before finally register one SaveStateEntry, we detect for duplicated
entries. This could be helpful to notify us asap instead of get
silent migration failures which could be hard to diagnose.
For example, this patch will generate a message like this (if without
previous fixes on x2apic) as long as we wants to boot a VM instance
with "-smp 200,maxcpus=288,sockets=2,cores=72,threads=2" and QEMU will
bail out even before VM starts:
savevm_state_handler_insert: Detected duplicate SaveStateEntry: id=apic, instance_id=0x0
Suggested-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231020090731.28701-10-quintela@redhat.com>
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>
This let us simplify code of this shape.
qemu_fflush(f);
int ret = qemu_file_get_error(f);
if (ret) {
return ret;
}
into:
int ret = qemu_fflush(f);
if (ret) {
return ret;
}
I updated all callers where there is any error check.
qemu_fclose() don't need to check for f->last_error because
qemu_fflush() returns it at the beggining of the function.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231025091117.6342-13-quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
qemu_file_transferred() don't exist anymore, so we can reuse the name.
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231025091117.6342-7-quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
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>
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>
There's a bug on dest that if a double fault triggered on dest qemu (a
network issue during postcopy-recover), we won't set PAUSED correctly
because we assumed we always came from ACTIVE.
Fix that by always overwriting the state to PAUSE.
We could also check for these two states, but maybe it's an overkill. We
did the same on the src QEMU to unconditionally switch to PAUSE anyway.
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: <20231004220240.167175-10-peterx@redhat.com>
A few code paths exist in the source code,where a migration is
marked as failed via MIGRATION_STATUS_FAILED, but the failure happens
outside of migration.c
In such cases, an error_report() call is made, however the current
MigrationState is never updated with the error description, and hence
clients like libvirt never know the actual reason for the failure.
This patch covers such cases outside of migration.c and updates the
error description at the appropriate places.
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: <20231003065538.244752-3-tejus.gk@nutanix.com>
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>
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>
We do a qemu_fclose() just after that, that also does a qemu_fflush(),
so remove one qemu_fflush().
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20230530183941.7223-3-quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Fast don't say much. Noflush indicates more clearly that it is like
qemu_file_transferred but without the flush.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20230530183941.7223-2-quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
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>
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>
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>
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>
Change all the functions that use it. It was already passed as
uint64_t.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20230504113841.23130-8-quintela@redhat.com>
migration_stats is just too long, and it is going to have more than
ram counters in the near future.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Lukas Straub <lukasstraub2@web.de>
There is already include/qemu/stats.h, so stats.h was a bad idea.
We want this file to not depend on anything else, we will move all the
migration counters/stats to this struct.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Lukas Straub <lukasstraub2@web.de>
For VMS_ARRAY typed vmsd fields, also dump the number of entries in the
array in -vmstate-dump.
Without such information, vmstate static checker can report false negatives
of incompatible vmsd on VMS_ARRAY typed fields, when the src/dst do not
have the same type of array defined. It's because in the checker we only
check against size of fields within a VMSD field.
One example: e1000e used to have a field defined as a boolean array with 5
entries, then removed it and replaced it with UNUSED (in 31e3f318c8):
- VMSTATE_BOOL_ARRAY(core.eitr_intr_pending, E1000EState,
- E1000E_MSIX_VEC_NUM),
+ VMSTATE_UNUSED(E1000E_MSIX_VEC_NUM),
It's a legal replacement but vmstate static checker is not happy with it,
because it checks only against the "size" field between the two
fields (here one is BOOL_ARRAY, the other is UNUSED):
For BOOL_ARRAY:
{
"field": "core.eitr_intr_pending",
"version_id": 0,
"field_exists": false,
"size": 1
},
For UNUSED:
{
"field": "unused",
"version_id": 0,
"field_exists": false,
"size": 5
},
It's not the script to blame because there's just not enough information
dumped to show the total size of the entry for an array. Add it.
Note that this will not break old vmstate checker because the field will
just be ignored.
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Instead of print it to STDERR, bring the error upwards so that it can be
reported via QMP responses.
E.g.:
{ "execute": "migrate-set-capabilities" ,
"arguments": { "capabilities":
[ { "capability": "postcopy-ram", "state": true } ] } }
{ "error":
{ "class": "GenericError",
"desc": "Postcopy is not supported: Host backend files need to be TMPFS
or HUGETLBFS only" } }
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Once that we are there, we rename the function to migrate_block()
to be consistent with all other capabilities.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
We move there all capabilities helpers from migration.c.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
Following David advise:
- looked through the history, capabilities are newer than 2012, so we
can remove that bit of the header.
- This part is posterior to Anthony.
Original Author is Orit. Once there,
I put myself. Peter Xu also did quite a bit of work here.
Anyone else wants/needs to be there? I didn't search too hard
because nobody asked before to be added.
What do you think?
It is clear from the context what that means, and such a long name
with the extra long names of the capabilities make very difficilut to
stay inside the 80 columns limit.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
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>
Nothing assigns to it after previous commit.
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Signed-off-by: Juan Quintela <quintela@redhat.com>
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>
I called the helper function from the wrong top level function.
This code was introduced in:
commit c8df4a7aef
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>
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>
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>
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>
... 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>
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>
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>
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>
We have two inclusion loops:
block/block.h
-> block/block-global-state.h
-> block/block-common.h
-> block/blockjob.h
-> block/block.h
block/block.h
-> block/block-io.h
-> block/block-common.h
-> block/blockjob.h
-> block/block.h
I believe these go back to Emanuele's reorganization of the block API,
merged a few months ago in commit d7e2fe4aac.
Fortunately, breaking them is merely a matter of deleting unnecessary
includes from headers, and adding them back in places where they are
now missing.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20221221133551.3967339-2-armbru@redhat.com>
Snapshot loading only expects to call deterministic handlers, not
non-deterministic ones. So introduce a way of registering handlers that
won't be called when reseting for snapshots.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Message-id: 20221025004327.568476-2-Jason@zx2c4.com
[PMM: updated json doc comment with Markus' text; fixed
checkpatch style nit]
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
To allow postcopy recovery, the ram fast load (preempt-only) dest QEMU thread
needs similar handling on fault tolerance. When ram_load_postcopy() fails,
instead of stopping the thread it halts with a semaphore, preparing to be
kicked again when recovery is detected.
A mutex is introduced to make sure there's no concurrent operation upon the
socket. To make it simple, the fast ram load thread will take the mutex during
its whole procedure, and only release it if it's paused. The fast-path socket
will be properly released by the main loading thread safely when there's
network failures during postcopy with that mutex held.
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20220707185506.27257-1-peterx@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Create a new socket for postcopy to be prepared to send postcopy requested
pages via this specific channel, so as to not get blocked by precopy pages.
A new thread is also created on dest qemu to receive data from this new channel
based on the ram_load_postcopy() routine.
The ram_load_postcopy(POSTCOPY) branch and the thread has not started to
function, and that'll be done in follow up patches.
Cleanup the new sockets on both src/dst QEMUs, meanwhile look after the new
thread too to make sure it'll be recycled properly.
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20220707185502.27149-1-peterx@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
dgilbert: With Peter's fix to quieten compiler warning on
start_migration
