On the POWER9 processor, the XIVE interrupt controller can control
interrupt sources using MMIO to trigger events, to EOI or to turn off
the sources. Priority management and interrupt acknowledgment is also
controlled by MMIO in the presenter sub-engine.
These MMIO regions are exposed to guests in QEMU with a set of 'ram
device' memory mappings, similarly to VFIO, and the VMAs are populated
dynamically with the appropriate pages using a fault handler.
But, these regions are an issue for migration. We need to discard the
associated RAMBlocks from the RAM state on the source VM and let the
destination VM rebuild the memory mappings on the new host in the
post_load() operation just before resuming the system.
To achieve this goal, the following introduces a new RAMBlock flag
RAM_MIGRATABLE which is updated in the vmstate_register_ram() and
vmstate_unregister_ram() routines. This flag is then used by the
migration to identify RAMBlocks to discard on the source. Some checks
are also performed on the destination to make sure nothing invalid was
sent.
This change impacts the boston, malta and jazz mips boards for which
migration compatibility is broken.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
In the vmstate.h file, we just need a struct name. Use a forward
declaration instead of an include, then adjust the one affected .c file
to include the file that is no longer implicit from the header.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
The first allow-oob=true command. It's used on destination side when
the postcopy migration is paused and ready for a recovery. After
execution, a new migration channel will be established for postcopy to
continue.
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180502104740.12123-21-peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
---
s/2.12/2.13/
This is hook function to be called when a postcopy migration wants to
resume from a failure. For each module, it should provide its own
recovery logic before we switch to the postcopy-active state.
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180502104740.12123-16-peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Creating new message to reply for MIG_CMD_POSTCOPY_RESUME. One uint32_t
is used as payload to let the source know whether destination is ready
to continue the migration.
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180502104740.12123-15-peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Introducing this new command to be sent when the source VM is ready to
resume the paused migration. What the destination does here is
basically release the fault thread to continue service page faults.
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180502104740.12123-14-peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Introducing new return path message MIG_RP_MSG_RECV_BITMAP to send
received bitmap of ramblock back to source.
This is the reply message of MIG_CMD_RECV_BITMAP, it contains not only
the header (including the ramblock name), and it was appended with the
whole ramblock received bitmap on the destination side.
When the source receives such a reply message (MIG_RP_MSG_RECV_BITMAP),
it parses it, convert it to the dirty bitmap by inverting the bits.
One thing to mention is that, when we send the recv bitmap, we are doing
these things in extra:
- converting the bitmap to little endian, to support when hosts are
using different endianess on src/dst.
- do proper alignment for 8 bytes, to support when hosts are using
different word size (32/64 bits) on src/dst.
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180502104740.12123-13-peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Add a new vm command MIG_CMD_RECV_BITMAP to request received bitmap for
one ramblock.
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180502104740.12123-12-peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Allows the fault thread to stop handling page faults temporarily. When
network failure happened (and if we expect a recovery afterwards), we
should not allow the fault thread to continue sending things to source,
instead, it should halt for a while until the connection is rebuilt.
When the dest main thread noticed the failure, it kicks the fault thread
to switch to pause state.
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180502104740.12123-7-peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
When there is IO error on the incoming channel (e.g., network down),
instead of bailing out immediately, we allow the dst vm to switch to the
new POSTCOPY_PAUSE state. Currently it is still simple - it waits the
new semaphore, until someone poke it for another attempt.
One note is that here on ram loading thread we cannot detect the
POSTCOPY_ACTIVE state, but we need to detect the more specific
POSTCOPY_INCOMING_RUNNING state, to make sure we have already loaded all
the device states.
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180502104740.12123-5-peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Notify the vhost-user slave on reception of the 'postcopy-listen'
event from the source.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Wire up a notifier to send a VHOST_USER_POSTCOPY_ADVISE
message on an incoming advise.
Later patches will fill in the behaviour/contents of the
message.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Postcopy migration of dirty bitmaps. Only named dirty bitmaps are migrated.
If destination qemu is already containing a dirty bitmap with the same name
as a migrated bitmap (for the same node), then, if their granularities are
the same the migration will be done, otherwise the error will be generated.
If destination qemu doesn't contain such bitmap it will be created.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-id: 20180313180320.339796-12-vsementsov@virtuozzo.com
[Changed '+' to '*' as per list discussion. --js]
Signed-off-by: John Snow <jsnow@redhat.com>
Only-postcopy savevm states (dirty-bitmap) don't need live iteration, so
to disable them and stop transporting empty sections there is a new
savevm handler.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 20180313180320.339796-10-vsementsov@virtuozzo.com
There would be savevm states (dirty-bitmap) which can migrate only in
postcopy stage. The corresponding pending is introduced here.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-id: 20180313180320.339796-6-vsementsov@virtuozzo.com
This patch does not allows saving/loading vmstate when
replay events queue is not empty. There is no reliable
way to save events queue, because it describes internal
coroutine state. Therefore saving and loading operations
should be deferred to another record/replay step.
Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
Message-Id: <20180227095214.1060.32939.stgit@pasha-VirtualBox>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
The previous commit improved compile time by including less of the
generated QAPI headers. This is impossible for stuff defined directly
in qapi-schema.json, because that ends up in headers that that pull in
everything.
Move everything but include directives from qapi-schema.json to new
sub-module qapi/misc.json, then include just the "misc" shard where
possible.
It's possible everywhere, except:
* monitor.c needs qmp-command.h to get qmp_init_marshal()
* monitor.c, ui/vnc.c and the generated qapi-event-FOO.c need
qapi-event.h to get enum QAPIEvent
Perhaps we'll get rid of those some other day.
Adding a type to qapi/migration.json now recompiles some 120 instead
of 2300 out of 5100 objects.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20180211093607.27351-25-armbru@redhat.com>
[eblake: rebase to master]
Signed-off-by: Eric Blake <eblake@redhat.com>
Let the callers take the object, then pass it to migrate_init().
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180208103132.28452-12-peterx@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
If the postcopy down due to some reason, we can always see this on dst:
qemu-system-x86_64: RP: Received invalid message 0x0000 length 0x0000
However in most cases that's not the real issue. The problem is that
qemu_get_be16() has no way to show whether the returned data is valid or
not, and we are _always_ assuming it is valid. That's possibly not wise.
The best approach to solve this would be: refactoring QEMUFile interface
to allow the APIs to return error if there is. However it needs quite a
bit of work and testing. For now, let's explicitly check the validity
first before using the data in all places for qemu_get_*().
This patch tries to fix most of the cases I can see. Only if we are with
this, can we make sure we are processing the valid data, and also can we
make sure we can capture the channel down events correctly.
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180208103132.28452-2-peterx@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
QEMUFile uses buffered IO so when writing small amounts (such as the Xen
device state file), the actual write call and any errors that may occur
only happen as part of qemu_fclose(). Therefore, report IO errors when
saving the device state under Xen by checking the return value of
qemu_fclose().
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Message-Id: <20180206163039.23661-1-ross.lagerwall@citrix.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
This cleanup makes the number of objects depending on qapi/error.h
drop from 1910 (out of 4743) to 1612 in my "build everything" tree.
While there, separate #include from file comment with a blank line,
and drop a useless comment on why qemu/osdep.h is included first.
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20180201111846.21846-5-armbru@redhat.com>
[Semantic conflict with commit 34e304e975 resolved, OSX breakage fixed]
If postcopy-ram was set on the source but not on the destination,
migration doesn't occur, the destination prints an error and boots
the guest:
qemu-system-ppc64: Expected vmdescription section, but got 0
We end up with two running instances.
This behaviour was introduced in 2.11 by commit 58110f0acb "migration:
split common postcopy out of ram postcopy" to prepare ground for the
upcoming dirty bitmap postcopy support. It adds a new case where the
source may send an empty postcopy advise because dirty bitmap doesn't
need to check page sizes like RAM postcopy does.
If the source has enabled postcopy-ram, then it sends an advise with
the page size values. If the destination hasn't enabled postcopy-ram,
then loadvm_postcopy_handle_advise() leaves the page size values on
the stream and returns. This confuses qemu_loadvm_state() later on
and causes the destination to start execution.
As discussed several times, postcopy-ram should be enabled both sides
to be functional. This patch changes the destination to perform some
extra checks on the advise length to ensure this is the case. Otherwise
an error is returned and migration is aborted.
Reported-by: Balamuruhan S <bala24@linux.vnet.ibm.com>
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Daniel Henrique Barboza <danielhb@linux.vnet.ibm.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <151791621042.19120.3103118434734245776.stgit@bahia>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Since qemu_fopen_channel_{in,out}put take references on the underlying
IO channels, make sure to release our references to them.
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Message-Id: <20171101142526.1006-2-ross.lagerwall@citrix.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
MAX_VM_CMD_PACKAGED_SIZE is a constant used in qemu_savevm_send_packaged
and loadvm_handle_cmd_packaged to determine whether a package is too
big to be sent or received. qemu_savevm_send_packaged is called inside
postcopy_start (migration/migration.c) to send the MigrationState
in a single blob to the destination, using the MIG_CMD_PACKAGED subcommand,
which will read it up using loadvm_handle_cmd_packaged. If the blob is
larger than MAX_VM_CMD_PACKAGED_SIZE, an error is thrown and the postcopy
migration is aborted. Both MAX_VM_CMD_PACKAGED_SIZE and MIG_CMD_PACKAGED
were introduced by commit 11cf1d984b ("MIG_CMD_PACKAGED: Send a packaged
chunk ..."). The constant has its original value of 1ul << 24 (16MB).
The current MAX_VM_CMD_PACKAGED_SIZE value is not enough to support postcopy
migration of bigger pseries guests. The blob size for a postcopy migration of
a pseries guest with the following setup:
qemu-system-ppc64 --nographic -vga none -machine pseries,accel=kvm -m 64G \
-smp 1,maxcpus=32 -device virtio-blk-pci,drive=rootdisk \
-drive file=f27.qcow2,if=none,cache=none,format=qcow2,id=rootdisk \
-netdev user,id=u1 -net nic,netdev=u1
Goes around 12MB. Bumping the RAM to 128G makes the blob sizes goes to 20MB.
With 256G the blob goes to 37MB - more than twice the current maximum size.
At this moment the pseries machine can handle guests with up to 1TB of RAM,
making this postcopy blob goes to 128MB of size approximately.
Following the discussions made in [1], there is a need to understand what
devices are aggressively consuming the blob in that manner and see if that
can be mitigated. Until then, we can set MAX_VM_CMD_PACKAGED_SIZE to the
maximum value allowed. Since the size is a 32 bit int variable, we can set
it as 1ul << 32, giving a maximum blob size of 4G that is enough to support
postcopy migration of 32TB RAM guests given the above constraints.
[1] https://lists.nongnu.org/archive/html/qemu-devel/2018-01/msg06313.html
Signed-off-by: Daniel Henrique Barboza <danielhb@linux.vnet.ibm.com>
Reported-by: Balamuruhan S <bala24@linux.vnet.ibm.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
When doing a live migration of a Xen guest with libxl, the images for
block devices are locked by the original QEMU process, and this prevent
the QEMU at the destination to take the lock and the migration fail.
>From QEMU point of view, once the RAM of a domain is migrated, there is
two QMP commands, "stop" then "xen-save-devices-state", at which point a
new QEMU is spawned at the destination.
Release locks in "xen-save-devices-state" so the destination can takes
them, if it's a live migration.
This patch add the "live" parameter to "xen-save-devices-state" which
default to true so older version of libxenlight can work with newer
version of QEMU.
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Route the errors from vsmtate_save_state back up through
vmstate_save and out to the normal device state path.
That's the normal error path done.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20170925112917.21340-6-dgilbert@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Modify the pre_save method on VMStateDescription to return an int
rather than void so that it potentially can fail.
Changed zillions of devices to make them return 0; the only
case I've made it return non-0 is hw/intc/s390_flic_kvm.c that already
had an error_report/return case.
Note: If you add an error exit in your pre_save you must emit
an error_report to say why.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20170925112917.21340-2-dgilbert@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
That tiny refactoring is necessary to be able to set
UFFD_FEATURE_THREAD_ID while requesting features, and then
to create downtime context in case when kernel supports it.
Signed-off-by: Alexey Perevalov <a.perevalov@samsung.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Split common postcopy staff from ram postcopy staff.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Now postcopy-able states are recognized by not NULL
save_live_complete_postcopy handler. But when we have several different
postcopy-able states, it is not convenient. Ram postcopy may be
disabled, while some other postcopy enabled, in this case Ram state
should behave as it is not postcopy-able.
This patch add separate has_postcopy handler to specify behaviour of
savevm state.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
If the bdrv_inactivate_all fails near the end of the migration,
the migration will fail and often the only diagnostics in the log
are an I/O error which you can't distinguish from an error on
the socket connection.
Add an error so we know when it's actually a block problem.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20170822170212.27347-1-dgilbert@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
We need to do things at load time and at cleanup time.
Signed-off-by: Juan Quintela <quintela@redhat.com>
--
Move the printing of the error message so we can print the device
giving the error.
Add call to postcopy stuff
Message-Id: <20170628095228.4661-4-quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
We need a cleanup for loads, so we rename here to be consistent.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
--
Rename htab_cleanup to htap_save_cleanup as dave suggestion
Message-Id: <20170628095228.4661-3-quintela@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
We are going to use it now for more than save live regions.
Once there rename qemu_savevm_state_begin() to qemu_savevm_state_setup().
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20170628095228.4661-2-quintela@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
These two parameters:
- MachineState::enforce_config_section
- MigrationState::send_configuration
are playing similar role here. This patch merges the first one into
second, then we'll have a single place to reference whether we need to
send the configuration section.
I didn't remove the MachineState.enforce_config_section field since when
applying that machine property (in machine_set_property()) we haven't
yet initialized global properties and migration object. Then, it's
still not easy to pass that boolean to MigrationState at such an early
time.
A natural benefit for current patch is that now we kept the meaning of
"enforce-config-section" since it'll still have the highest
priority (that's what "enforce" mean I guess).
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <1498536619-14548-10-git-send-email-peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Move it into MigrationState, revert its meaning and renaming it to
send_section_footer, with a property bound to it. Same trick is played
like previous patches.
Removing savevm_skip_section_footers().
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <1498536619-14548-9-git-send-email-peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
It was in SaveState but now moved to MigrationState altogether, reverted
its meaning, then renamed to "send_configuration". Again, using
HW_COMPAT_2_3 for old PC/SPAPR machines, and accel_register_prop() for
xen_init().
Removing savevm_skip_configuration().
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <1498536619-14548-8-git-send-email-peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
One less global variable, and it does only matter with migration.
We keep the old "--only-migratable" option, but also now we support:
-global migration.only-migratable=true
Currently still keep the old interface.
Hmm, now vl.c has no way to access migrate_get_current(). Export a
function for it to setup only_migratable.
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <1498536619-14548-7-git-send-email-peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
migration_incoming_state_destroy() uses qemu_fclose() on the vmstate
file. Make sure to call it inside an AioContext acquire/release region.
This fixes an 'qemu: qemu_mutex_unlock: Operation not permitted' abort
in loadvm.
This patch closes the vmstate file before ending the drained region.
Previously we closed the vmstate file after ending the drained region.
The order does not matter.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
blk/bdrv_drain_all() only takes effect for a single instant and then
resumes block jobs, guest devices, and other external clients like the
NBD server. This can be handy when performing a synchronous drain
before terminating the program, for example.
Monitor commands usually need to quiesce I/O across an entire code
region so blk/bdrv_drain_all() is not suitable. They must use
bdrv_drain_all_begin/end() to mark the region. This prevents new I/O
requests from slipping in or worse - block jobs completing and modifying
the graph.
I audited other blk/bdrv_drain_all() callers but did not find anything
that needs a similar fix. This patch fixes the savevm/loadvm commands.
Although I haven't encountered a read world issue this makes the code
safer.
Suggested-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
AioContext was designed to allow nested acquire/release calls. It uses
a recursive mutex so callers don't need to worry about nesting...or so
we thought.
BDRV_POLL_WHILE() is used to wait for block I/O requests. It releases
the AioContext temporarily around aio_poll(). This gives IOThreads a
chance to acquire the AioContext to process I/O completions.
It turns out that recursive locking and BDRV_POLL_WHILE() don't mix.
BDRV_POLL_WHILE() only releases the AioContext once, so the IOThread
will not be able to acquire the AioContext if it was acquired
multiple times.
Instead of trying to release AioContext n times in BDRV_POLL_WHILE(),
this patch simply avoids nested locking in save_vmstate(). It's the
simplest fix and we should step back to consider the big picture with
all the recent changes to block layer threading.
This patch is the final fix to solve 'savevm' hanging with -object
iothread.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Previously, dst side will immediately try to lock the write byte upon
receiving QEMU_VM_EOF, but at src side, bdrv_inactivate_all() is only
done after sending it. If the src host is under load, dst may fail to
acquire the lock due to racing with the src unlocking it.
Fix this by hoisting the bdrv_inactivate_all() operation before
QEMU_VM_EOF.
N.B. A further improvement could possibly be done to cleanly handover
locks between src and dst, so that there is no window where a third QEMU
could steal the locks and prevent src and dst from running.
N.B. This commit includes a minor improvement to the error handling
by using qemu_file_set_error().
Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Fam Zheng <famz@redhat.com>
Message-id: 20170616160658.32290-1-famz@redhat.com
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
[PMM: noted qemu_file_set_error() use in commit as suggested by Daniel]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Nothing uses it outside of migration.h
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
It don't belong anywhere else, just the global state where everybody
can stick other things.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
They are indpendent, and nowadays almost every device register things
with qdev->vmsd.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
