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2015-11-10Don't sync dirty bitmaps in postcopyDr. David Alan Gilbert
Once we're in postcopy the source processors are stopped and memory shouldn't change any more, so there's no need to look at the dirty map. There are two notes to this: 1) If we do resync and a page had changed then the page would get sent again, which the destination wouldn't allow (since it might have also modified the page) 2) Before disabling this I'd seen very rare cases where a page had been marked dirtied although the memory contents are apparently identical Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Reviewed-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10postcopy: Check order of received target pagesDr. David Alan Gilbert
Ensure that target pages received within a host page are in order. This shouldn't trigger, but in the cases where the sender goes wrong and sends stuff out of order it produces a corruption that's really nasty to debug. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10Postcopy: Use helpers to map pages during migrationDr. David Alan Gilbert
In postcopy, the destination guest is running at the same time as it's receiving pages; as we receive new pages we must put them into the guests address space atomically to avoid a running CPU accessing a partially written page. Use the helpers in postcopy-ram.c to map these pages. qemu_get_buffer_in_place is used to avoid a copy out of qemu_file in the case that postcopy is going to do a copy anyway. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10postcopy_ram.c: place_page and helpersDr. David Alan Gilbert
postcopy_place_page (etc) provide a way for postcopy to place a page into guests memory atomically (using the copy ioctl on the ufd). Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Amit Shah <amit.shah@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10Page request: Consume pages off the post-copy queueDr. David Alan Gilbert
When transmitting RAM pages, consume pages that have been queued by MIG_RPCOMM_REQPAGE commands and send them ahead of normal page scanning. Note: a) After a queued page the linear walk carries on from after the unqueued page; there is a reasonable chance that the destination was about to ask for other closeby pages anyway. b) We have to be careful of any assumptions that the page walking code makes, in particular it does some short cuts on its first linear walk that break as soon as we do a queued page. c) We have to be careful to not break up host-page size chunks, since this makes it harder to place the pages on the destination. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10Page request: Process incoming page requestDr. David Alan Gilbert
On receiving MIG_RPCOMM_REQ_PAGES look up the address and queue the page. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Amit Shah <amit.shah@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10Page request: Add MIG_RP_MSG_REQ_PAGES reverse commandDr. David Alan Gilbert
Add MIG_RP_MSG_REQ_PAGES command on Return path for the postcopy destination to request a page from the source. Two versions exist: MIG_RP_MSG_REQ_PAGES_ID that includes a RAMBlock name and start/len MIG_RP_MSG_REQ_PAGES that just has start/len for use with the same RAMBlock as a previous MIG_RP_MSG_REQ_PAGES_ID Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10Postcopy: End of iterationDr. David Alan Gilbert
The end of migration in postcopy is a bit different since some of the things normally done at the end of migration have already been done on the transition to postcopy. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10Postcopy: Postcopy startup in migration threadDr. David Alan Gilbert
Rework the migration thread to setup and start postcopy. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Amit Shah <amit.shah@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10postcopy: ram_enable_notify to switch on userfaultDr. David Alan Gilbert
Mark the area of RAM as 'userfault' Start up a fault-thread to handle any userfaults we might receive from it (to be filled in later) Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Reviewed-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10postcopy: Incoming initialisationDr. David Alan Gilbert
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Reviewed-by: Amit Shah <amit.shah@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10migration_completion: Take current stateDr. David Alan Gilbert
Soon we'll be in either ACTIVE or POSTCOPY_ACTIVE when we complete migration, and we need to know which we expect to be in to change state safely. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10Postcopy: Maintain unsentmapDr. David Alan Gilbert
Maintain an 'unsentmap' of pages that have yet to be sent. This is used in the following patches to discard some set of the pages already sent as we enter postcopy mode. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10Add qemu_savevm_state_complete_postcopyDr. David Alan Gilbert
Add qemu_savevm_state_complete_postcopy to complement qemu_savevm_state_complete_precopy together with a new save_live_complete_postcopy method on devices. The save_live_complete_precopy method is called on all devices during a precopy migration, and all non-postcopy devices during a postcopy migration at the transition. The save_live_complete_postcopy method is called at the end of postcopy for all postcopiable devices. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10Avoid sending vmdescription during postcopyDr. David Alan Gilbert
VMDescription is normally sent at the end, after all of the devices; however that's not the end for postcopy, so just don't send it when in postcopy. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10MIGRATION_STATUS_POSTCOPY_ACTIVE: Add new migration stateDr. David Alan Gilbert
'MIGRATION_STATUS_POSTCOPY_ACTIVE' is entered after migrate_start_postcopy 'migration_in_postcopy' is provided for other sections to know if they're in postcopy. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10migration_completion: Take current stateDr. David Alan Gilbert
Soon we'll be in either ACTIVE or POSTCOPY_ACTIVE when we complete migration, and we need to know which we expect to be in to change state safely. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10migrate_start_postcopy: Command to trigger transition to postcopyDr. David Alan Gilbert
Once postcopy is enabled (with migrate_set_capability), the migration will still start on precopy mode. To cause a transition into postcopy the: migrate_start_postcopy command must be issued. Postcopy will start sometime after this (when it's next checked in the migration loop). Issuing the command before migration has started will error, and issuing after it has finished is ignored. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10postcopy: OS support testDr. David Alan Gilbert
Provide a check to see if the OS we're running on has all the bits needed for postcopy. Creates postcopy-ram.c which will get most of the other helpers we need. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Amit Shah <amit.shah@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10Modify save_live_pending for postcopyDr. David Alan Gilbert
Modify save_live_pending to return separate postcopiable and non-postcopiable counts. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10MIG_CMD_PACKAGED: Send a packaged chunk of migration streamDr. David Alan Gilbert
MIG_CMD_PACKAGED is a migration command that wraps a chunk of migration stream inside a package whose length can be determined purely by reading its header. The destination guarantees that the whole MIG_CMD_PACKAGED is read off the stream prior to parsing the contents. This is used by postcopy to load device state (from the package) while leaving the main stream free to receive memory pages. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Amit Shah <amit.shah@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10Add wrappers and handlers for sending/receiving the postcopy-ram migration ↵Dr. David Alan Gilbert
messages. The state of the postcopy process is managed via a series of messages; * Add wrappers and handlers for sending/receiving these messages * Add state variable that track the current state of postcopy Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Amit Shah <amit.shah@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10Add migration-capability boolean for postcopy-ram.Dr. David Alan Gilbert
The 'postcopy ram' capability allows postcopy migration of RAM; note that the migration starts off in precopy mode until postcopy mode is triggered (see the migrate_start_postcopy patch later in the series). Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10Rework loadvm path for subloopsDr. David Alan Gilbert
Postcopy needs to have two migration streams loading concurrently; one from memory (with the device state) and the other from the fd with the memory transactions. Split the core of qemu_loadvm_state out so we can use it for both. Allow the inner loadvm loop to quit and cause the parent loops to exit as well. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10Return path: Source handling of return pathDr. David Alan Gilbert
Open a return path, and handle messages that are received upon it. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10migration_is_setup_or_activeDr. David Alan Gilbert
Add 'migration_is_setup_or_active' utility function to check state. (It gets postcopy added to it's list later on in the series) Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10Return path: Send responses from destination to sourceDr. David Alan Gilbert
Add migrate_send_rp_message to send a message from destination to source along the return path. (It uses a mutex to let it be called from multiple threads) Add migrate_send_rp_shut to send a 'shut' message to indicate the destination is finished with the RP. Add migrate_send_rp_ack to send a 'PONG' message in response to a PING Use it in the MSG_RP_PING handler Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Amit Shah <amit.shah@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10Return path: Control commandsDr. David Alan Gilbert
Add two src->dest commands: * OPEN_RETURN_PATH - To request that the destination open the return path * PING - Request an acknowledge from the destination Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Amit Shah <amit.shah@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10Migration commandsDr. David Alan Gilbert
Create QEMU_VM_COMMAND section type for sending commands from source to destination. These commands are not intended to convey guest state but to control the migration process. For use in postcopy. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Amit Shah <amit.shah@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10Return path: socket_writev_buffer: Block even on non-blocking fd'sDr. David Alan Gilbert
The destination sets the fd to non-blocking on incoming migrations; this also affects the return path from the destination, and thus we need to make sure we can safely write to the return path. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Amit Shah <amit.shah@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10Return path: Open a return path on QEMUFile for socketsDr. David Alan Gilbert
Postcopy needs a method to send messages from the destination back to the source, this is the 'return path'. Wire it up for 'socket' QEMUFile's. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10Rename save_live_complete to save_live_complete_precopyDr. David Alan Gilbert
In postcopy we're going to need to perform the complete phase for postcopiable devices at a different point, start out by renaming all of the 'complete's to make the difference obvious. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Amit Shah <amit.shah@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10migrate_init: Call from savevmDr. David Alan Gilbert
Suspend to file is very much like a migrate, and it makes life easier if we have the Migration state available, so initialise it in the savevm.c code for suspending. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Reviewed-by: Juan Quintela <quintela@redhat.com> Reviewd-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10ram_load: Factor out host_from_stream_offset call and checkDr. David Alan Gilbert
The main RAM load loop has a call to host_from_stream_offset for each page type that actually loads data with the same test; factor it out before the switch. The host = NULL is to silence a bogus gcc warning of an unitialised in the RAM_SAVE_COMPRESS_PAGE case, it doesn't seem to realise that host is always initialised by the if at the top in the cases the switch takes. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10ram_debug_dump_bitmap: Dump a migration bitmap as textDr. David Alan Gilbert
Useful for debugging the migration bitmap and other bitmaps of the same format (including the sentmap in postcopy). The bitmap is printed to stderr. Lines that are all the expected value are excluded so the output can be quite compact for many bitmaps. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Amit Shah <amit.shah@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10Add wrapper for setting blocking status on a QEMUFileDr. David Alan Gilbert
Add a wrapper to change the blocking status on a QEMUFile rather than having to use qemu_set_block(qemu_get_fd(f)); it seems best to avoid exposing the fd since not all QEMUFile's really have one. With this wrapper we could move the implementation down to be different on different transports. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Amit Shah <amit.shah@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10Add qemu_get_buffer_in_place to avoid copies some of the timeDr. David Alan Gilbert
qemu_get_buffer always copies the data it reads to a users buffer, however in many cases the file buffer inside qemu_file could be given back to the caller, avoiding the copy. This isn't always possible depending on the size and alignment of the data. Thus 'qemu_get_buffer_in_place' either copies the data to a supplied buffer or updates a pointer to the internal buffer if convenient. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10Rename mis->file to from_src_fileDr. David Alan Gilbert
'file' becomes confusing when you have flows in each direction; rename to make it clear. This leaves just the main forward direction ms->file, which is used in a lot of places and is probably not worth renaming given the churn. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10qemu_ram_block_by_nameDr. David Alan Gilbert
Add a function to find a RAMBlock by name; use it in two of the places that already open code that loop; we've got another use later in postcopy. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-10Move configuration section writingDr. David Alan Gilbert
The vmstate_configuration is currently written in 'qemu_savevm_state_begin', move it to 'qemu_savevm_state_header' since it's got a hard requirement that it must be the 1st thing after the header. (In postcopy some 'command' sections get sent early before the saving of the main sections and hence before qemu_savevm_state_begin). Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Amit Shah <amit.shah@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-11-04migration: code clean upLiang Li
Just clean up code, no behavior change. Signed-off-by: Liang Li <liang.z.li@intel.com> Reviewed-by: Juan Quintela <quintela@redhat.com>al3 Reviewed-by: Amit Shah <amit.shah@redhat.com>al3 Signed-off-by: Juan Quintela <quintela@redhat.com>al3
2015-11-04migration: rename cancel to cleanup in SaveVMHandlesLiang Li
'cleanup' seems more appropriate than 'cancel'. Signed-off-by: Liang Li <liang.z.li@intel.com> Reviewed-by: Juan Quintela <quintela@redhat.com>al3 Reviewed-by: Amit Shah <amit.shah@redhat.com>al3 Signed-off-by: Juan Quintela <quintela@redhat.com>al3
2015-11-04migration: rename qemu_savevm_state_cancelLiang Li
The function qemu_savevm_state_cancel is called after the migration in migration_thread, it seems strange to 'cancel' it after completion, rename it to qemu_savevm_state_cleanup looks better. Signed-off-by: Liang Li <liang.z.li@intel.com> Reviewed-by: Juan Quintela <quintela@redhat.com>al3 Reviewed-by: Amit Shah <amit.shah@redhat.com>al3 Signed-off-by: Juan Quintela <quintela@redhat.com>al3
2015-11-04migration: defer migration_end & blk_mig_cleanupLiang Li
Because of the patch 3ea3b7fa9af067982f34b of kvm, which introduces a lazy collapsing of small sptes into large sptes mechanism, now migration_end() is a time consuming operation because it calls memroy_global_dirty_log_stop(), which will trigger the dropping of small sptes operation and takes about dozens of milliseconds, so call migration_end() before all the vmsate data has already been transferred to the destination will prolong VM downtime. This operation should be deferred after all the data has been transferred to the destination. blk_mig_cleanup() can be deferred too. For a VM with 8G RAM, this patch can reduce the VM downtime about 30 ms. Signed-off-by: Liang Li <liang.z.li@intel.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com>al3 Reviewed-by: Amit Shah <amit.shah@redhat.com>al3 Signed-off-by: Juan Quintela <quintela@redhat.com>al3
2015-10-23block: Prepare for NULL BDSMax Reitz
blk_bs() will not necessarily return a non-NULL value any more (unless blk_is_available() is true or it can be assumed to otherwise, e.g. because it is called immediately after a successful blk_new_with_bs() or blk_new_open()). Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-10-20coroutine: move into libqemuutil.a libraryDaniel P. Berrange
The coroutine files are currently referenced by the block-obj-y variable. The coroutine functionality though is already used by more than just the block code. eg migration code uses coroutine yield. In the future the I/O channel code will also use the coroutine yield functionality. Since the coroutine code is nicely self-contained it can be easily built as part of the libqemuutil.a library, making it widely available. The headers are also moved into include/qemu, instead of the include/block directory, since they are now part of the util codebase, and the impl was never in the block/ directory either. Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-10-15migration: fix deadlockDenis V. Lunev
Release qemu global mutex before call synchronize_rcu(). synchronize_rcu() waiting for all readers to finish their critical sections. There is at least one critical section in which we try to get QGM (critical section is in address_space_rw() and prepare_mmio_access() is trying to aquire QGM). Both functions (migration_end() and migration_bitmap_extend()) are called from main thread which is holding QGM. Thus there is a race condition that ends up with deadlock: main thread working thread Lock QGA | | Call KVM_EXIT_IO handler | | | Open rcu reader's critical section Migration cleanup bh | | | synchronize_rcu() is | waiting for readers | | prepare_mmio_access() is waiting for QGM \ / deadlock The patch changes bitmap freeing from direct g_free after synchronize_rcu to free inside call_rcu. Signed-off-by: Denis V. Lunev <den@openvz.org> Reported-by: Igor Redko <redkoi@virtuozzo.com> Tested-by: Igor Redko <redkoi@virtuozzo.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com> CC: Anna Melekhova <annam@virtuozzo.com> CC: Juan Quintela <quintela@redhat.com> CC: Amit Shah <amit.shah@redhat.com> CC: Paolo Bonzini <pbonzini@redhat.com> CC: Wen Congyang <wency@cn.fujitsu.com>
2015-10-15migration: announce VM's new home just before VM is runnableAmit Shah
We were announcing the dest host's IP as our new IP a bit too soon -- if there were errors detected after this announcement was done, the migration is failed and the VM could continue running on the src host -- causing problems later. Move around the qemu_announce_self() call so it's done just before the VM is runnable. Signed-off-by: Amit Shah <amit.shah@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-10-15Migration: Generate the completed event only when we completeDr. David Alan Gilbert
The current migration-completed event is generated a bit too early, which means that an eager libvirt that's ready to go as soon as it sees the event ends up racing with the actual end of migration. This corresponds to RH bug: https://bugzilla.redhat.com/show_bug.cgi?id=1271145 Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Amit Shah <amit.shah@redhat.com> xSigned-off-by: Juan Quintela <quintela@redhat.com>
2015-09-30migration: Disambiguate MAX_THROTTLEJason J. Herne
Migration has a define for MAX_THROTTLE. Update comment to clarify that this is used for throttling transfer speed. Hopefully this will prevent it from being confused with a guest cpu throttling entity. Signed-off-by: Jason J. Herne <jjherne@linux.vnet.ibm.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com>