The drivers were accepting domain configs without checking if those
were actually meant for them. For example the LXC driver happily
accepts configs with type QEMU.

Add a check for the expected domain types to the virDomainDefParse*
functions.

For controlled shutdown we issue a 'system_powerdown' command
to the QEMU monitor. This triggers an ACPI event which (most)
guest OS wire up to a controlled shutdown. There is no equiv
ACPI event to trigger a controlled reboot. This patch attempts
to fake a reboot.

 - In qemuDomainObjPrivatePtr we have a bool fakeReboot
   flag.
 - The virDomainReboot method sets this flag and then
   triggers a normal 'system_powerdown'.
 - The QEMU process is started with '-no-shutdown'
   so that the guest CPUs pause when it powers off the
   guest
 - When we receive the 'POWEROFF' event from QEMU JSON
   monitor if fakeReboot is not set we invoke the
   qemuProcessKill command and shutdown continues
   normally
 - If fakeReboot was set, we spawn a background thread
   which issues 'system_reset' to perform a warm reboot
   of the guest hardware. Then it issues 'cont' to
   start the CPUs again

* src/qemu/qemu_command.c: Add -no-shutdown flag if
  we have JSON support
* src/qemu/qemu_domain.h: Add 'fakeReboot' flag to
  qemuDomainObjPrivate struct
* src/qemu/qemu_driver.c: Fake reboot using the
  system_powerdown command if JSON support is available
* src/qemu/qemu_monitor.c, src/qemu/qemu_monitor.h,
  src/qemu/qemu_monitor_json.c, src/qemu/qemu_monitor_json.h,
  src/qemu/qemu_monitor_text.c, src/qemu/qemu_monitor_text.h: Add
  binding for system_reset command
* src/qemu/qemu_process.c: Reset the guest & start CPUs if
  fakeReboot is set

The QEMU integrates with the lock manager instructure in a number
of key places

 * During startup, a lock is acquired in between the fork & exec
 * During startup, the libvirtd process acquires a lock before
   setting file labelling
 * During shutdown, the libvirtd process acquires a lock
   before restoring file labelling
 * During hotplug, unplug & media change the libvirtd process
   holds a lock while setting/restoring labels

The main content lock is only ever held by the QEMU child process,
or libvirtd during VM shutdown. The rest of the operations only
require libvirtd to hold the metadata locks, relying on the active
QEMU still holding the content lock.

* src/qemu/qemu_conf.c, src/qemu/qemu_conf.h,
  src/qemu/libvirtd_qemu.aug, src/qemu/test_libvirtd_qemu.aug:
  Add config parameter for configuring lock managers
* src/qemu/qemu_driver.c: Add calls to the lock manager

Update the qemuDomainMigrateBegin method so that it accepts
an optional incoming XML document. This will be validated
for ABI compatibility against the current domain config,
and if this check passes, will be passed back out for use
by the qemuDomainMigratePrepare method on the target

* src/qemu/qemu_domain.c, src/qemu/qemu_domain.h,
  src/qemu/qemu_migration.c: Allow custom XML to be passed

Originally most of libvirt domain-specific calls were blocking
during a migration.
A new mechanism to allow specific calls (blkstat/blkinfo) to be
executed in such condition has been implemented.
In the long term it'd be desirable to get a more general
solution to mark further APIs as migration safe, without needing
special case code.

 * src/qemu/qemu_migration.c: add some additional job signal
   flags for doing blkstat/blkinfo during a migration
 * src/qemu/qemu_domain.c: add a condition variable that can be
   used to efficiently wait for the migration code to clear the
   signal flag
 * src/qemu/qemu_driver.c: execute blkstat/blkinfo using the
   job signal flags during migration

As well as taint warnings going to the main libvirt log,
add taint warnings to the per-domain logfile

  Domain id=3 is tainted: high-privileges
  Domain id=3 is tainted: disk-probing
  Domain id=3 is tainted: shell-scripts
  Domain id=3 is tainted: custom-monitor

* src/qemu/qemu_domain.c, src/qemu/qemu_domain.h: Enhance
  qemuDomainTaint to also log to the domain logfile
* src/qemu/qemu_driver.c: Pass -1 for logFD to taint methods to
  auto-append to logfile
* src/qemu/qemu_process.c: Pass open logFD at startup for taint
  methods

The qemuDomainAppendLog method allows writing a formatted string
to the end of the domain logfile, optionally opening it if needed.

* src/qemu/qemu_domain.c, src/qemu/qemu_domain.h: Add
  qemuDomainAppendLog

Move the qemuProcessLogReadFD and qemuProcessLogFD methods
into qemu_domain.c, renaming them to qemuDomainCreateLog
and qemuDomainOpenLog.

* src/qemu/qemu_domain.c, src/qemu/qemu_domain.h: Add
  qemuDomainCreateLog and qemuDomainOpenLog.
* src/qemu/qemu_process.c: Remove qemuProcessLogFD
  and qemuProcessLogReadFD

Wire up logging of VM tainting to the QEMU driver

 - If running QEMU as root user/group or without capabilities
   being cleared
 - If passing custom QEMU command line args
 - If issuing custom QEMU monitor commands
 - If using a network interface config with an associated
   shell script
 - If using a disk config relying on format probing

The warnings, per-VM appear in the main libvirtd logs

  11:56:17.571: 10832: warning : qemuDomainObjTaint:712 : Domain id=1 name='l2' uuid=c7a3edbd-edaf-9455-926a-d65c16db1802 is tainted: high-privileges
  11:56:17.571: 10832: warning : qemuDomainObjTaint:712 : Domain id=1 name='l2' uuid=c7a3edbd-edaf-9455-926a-d65c16db1802 is tainted: disk-probing

The taint flags are reset when the VM is stopped.

* src/qemu/qemu_domain.c, src/qemu/qemu_domain.h: Helper APIs
  for logging taint warnings
* src/qemu/qemu_driver.c: Log tainting with custom QEMU monitor
  commands and disk/net hotplug with unsupported configs
* src/qemu/qemu_process.c: Log tainting at startup based on
  unsupported configs

To cope with the QEMU binary being changed while a VM is running,
it is neccessary to persist the original qemu capabilities at the
time the VM is booted.

* src/qemu/qemu_capabilities.c, src/qemu/qemu_capabilities.h: Add
  an enum for a string rep of every capability
* src/qemu/qemu_domain.c, src/qemu/qemu_domain.h: Support for
  storing capabilities in the domain status XML
* src/qemu/qemu_process.c: Populate & free QEMU capabilities at
  domain startup

Enhance the QEMU migration monitoring loop, so that it can get
a signal to change migration speed on the fly

* src/qemu/qemu_domain.h: Add signal for changing speed on the fly
* src/qemu/qemu_driver.c: Wire up virDomainMigrateSetSpeed driver
* src/qemu/qemu_migration.c: Support signal for changing speed

The introduction of the v3 migration protocol, along with
support for migration cookies, will significantly expand
the size of the migration code. Move it all to a separate
file to make it more manageable

The functions are not moved 100%. The API entry points
remain in the main QEMU driver, but once the public
virDomainPtr is resolved to the internal virDomainObjPtr,
all following code is moved.

This will allow the new v3 API entry points to call into the
same shared internal migration functions

* src/qemu/qemu_domain.c, src/qemu/qemu_domain.h: Add
  qemuDomainFormatXML helper method
* src/qemu/qemu_driver.c: Remove all migration code
* src/qemu/qemu_migration.c, src/qemu/qemu_migration.h: Add
  all migration code.

Move the qemudStartVMDaemon and qemudShutdownVMDaemon
methods into a separate file, renaming them to
qemuProcessStart, qemuProcessStop. All helper methods
called by these are also moved & renamed to match

* src/Makefile.am: Add qemu_process.c/.h
* src/qemu/qemu_command.c: Add qemuDomainAssignPCIAddresses
* src/qemu/qemu_command.h: Add VNC port min/max
* src/qemu/qemu_domain.c, src/qemu/qemu_domain.h: Add
  domain event queue helpers
* src/qemu/qemu_driver.c, src/qemu/qemu_driver.h: Remove
  all QEMU process startup/shutdown functions
* src/qemu/qemu_process.c, src/qemu/qemu_process.h: Add
  all QEMU process startup/shutdown functions

* src/conf/domain_conf.h (virDomainChrDeviceType): Drop monitor.
* src/conf/domain_conf.c (virDomainChrDevice)
(virDomainChrDefParseTargetXML, virDomainChrDefFormat): Drop
monitor support.
* src/qemu/qemu_command.h (qemuBuildCommandLine): Alter signature.
* src/qemu/qemu_monitor.h (qemuMonitorOpen): Likewise.
* src/qemu/qemu_domain.h (_qemuDomainObjPrivate): Change type of
monConfig.
* src/qemu/qemu_domain.c (qemuDomainObjPrivateFree)
(qemuDomainObjPrivateXMLFormat, qemuDomainObjPrivateXMLParse):
Adjust to type change.
* src/qemu/qemu_command.c (qemuBuildCommandLine): Likewise.
* src/qemu/qemu_driver.c (qemuPrepareMonitorChr)
(qemudStartVMDaemon, qemuDomainXMLToNative, qemuConnectMonitor)
(qemudShutdownVMDaemon): Likewise.
* src/qemu/qemu_hotplug.c (qemuDomainAttachNetDevice): Likewise.
* src/qemu/qemu_monitor.c (qemuMonitorOpen): Likewise.
* tests/qemuxml2argvtest.c (testCompareXMLToArgvFiles): Likewise.

To allow the APIs to be used from separate files, move the domain
lock / job helper code into qemu_domain.c

* src/qemu/qemu_domain.c, src/qemu/qemu_domain.h: Add domain lock
  / job code
* src/qemu/qemu_driver.c: Remove domain lock / job code

Move the code for handling the QEMU virDomainObjPtr private
data, and custom XML namespace into a separate file

* src/qemu/qemu_domain.c, src/qemu/qemu_domain.h: New file
  for private data & namespace code
* src/qemu/qemu_driver.c, src/qemu/qemu_driver.h: Remove
  private data & namespace code
* src/qemu/qemu_driver.h, src/qemu/qemu_command.h: Update
  includes
* src/Makefile.am: Add src/qemu/qemu_domain.c