To enable it to be called from multiple locations, split out
the code for building the -drive arg string. This will be needed
by later patches which do drive hotplug, the conversion to use
-device, and the conversion to controller/bus/unit addressing

* src/qemu/qemu_conf.c, src/qemu/qemu_conf.h: Add qemuBuildDriveStr
  for building -drive arg string

Convert the QEMU monitor APIs over to use virDomainDeviceAddress
structs for passing addresses in/out, instead of individual bits.
This makes the number of parameters smaller & easier to deal with.
No functional change

* src/qemu/qemu_driver.c, src/qemu/qemu_monitor.c,
  src/qemu/qemu_monitor.h, src/qemu/qemu_monitor_text.c,
  src/qemu/qemu_monitor_text.h: Change monitor hotplug APIs to
  take an explicit address ptr for all host/guest addresses

When parsing the <disk> element specification, if no <address>
is provided for the disk, then automatically assign one based on
the <target dev='sdXX'/> device name. This provides for backwards
compatability with existing applications using libvirt, while also
allowing new apps to have complete fine grained control.

* src/conf/domain_conf.h, src/conf/domain_conf.c,
  src/libvirt_private.syms: Add virDomainDiskDefAssignAddress()
  for assigning a controller/bus/unit address based on disk target
* src/qemu/qemu_conf.c: Call virDomainDiskDefAssignAddress() after
  generating XML from ARGV
* tests/qemuxml2argvdata/*.xml: Add in drive address information
  to all XML files

All guest devices now use a common device address structure
summarized by:

  enum virDomainDeviceAddressType {
    VIR_DOMAIN_DEVICE_ADDRESS_TYPE_NONE,
    VIR_DOMAIN_DEVICE_ADDRESS_TYPE_PCI,
  };

  struct _virDomainDevicePCIAddress {
    unsigned int domain;
    unsigned int bus;
    unsigned int slot;
    unsigned int function;
  };

  struct _virDomainDeviceInfo {
    int type;
    union {
        virDomainDevicePCIAddress pci;
    } addr;
  };

This replaces the anonymous structs in Disk/Net/Hostdev data
structures. Where available, the address is *always* printed
in the XML file, instead of being hidden in the internal state
file.

  <address type='pci' domain='0x0000' bus='0x1e' slot='0x07' function='0x0'/>

The structure definition is based on Wolfgang Mauerer's disk
controller patch series.

* docs/schemas/domain.rng: Define the <address> syntax and
  associate it with disk/net/hostdev devices
* src/conf/domain_conf.h, src/conf/domain_conf.c,
  src/libvirt_private.syms: APIs for parsing/formatting address
  information. Also remove the QEMU specific 'pci_addr' attributes
* src/qemu/qemu_driver.c: Replace use of 'pci_addr' attrs with
  new standardized format.

Based off how QEMU does it, look through /sys/bus/usb/devices/* for
matching vendor:product info, and if found, use info from the surrounding
files to build the device's /dev/bus/usb path.

This fixes USB device assignment by vendor:product when running qemu
as non-root (well, it should, but for some reason I couldn't reproduce
the failure people are seeing in [1], but it appears to work properly)

[1] https://bugzilla.redhat.com/show_bug.cgi?id=542450

This way we won't squash the original error report in
MigratePerform, as is done for P2P and Tunneled migration.

qemudWaitForMonitor calls qemudReadLogOutput with qemudFindCharDevicePTYs
as callback. qemudFindCharDevicePTYs calls qemudExtractTTYPath to assign
a string to chr->data.file.path. Afterwards qemudWaitForMonitor may call
qemudFindCharDevicePTYsMonitor that overwrites chr->data.file.path without
freeing the old value. This results in leaking the memory allocated by
qemudExtractTTYPath.

Report an OOM error if the strdup in qemudFindCharDevicePTYsMonitor fails.

The -mem-prealloc flag should be used when using large pages
This ensures qemu tries to allocate all required memory immediately,
rather than when first used. The latter mode will crash qemu
if hugepages aren't available when accessed, while the former
should gracefully fallback to non-hugepages.

* src/qemu/qemu_conf.c: add -mem-prealloc flag to qemu command line
  when using large pages

The behavior for the qemu balloon device has changed.  Formerly, a virtio
balloon device was provided by default.  Now, '-balloon virtio' must be
specified on the command line to enable it.  This patch causes libvirt to
add '-balloon virtio' to the command line whenever the -balloon option is
available.
* src/qemu/qemu_conf.c src/qemu/qemu_conf.h: check for the new flag and
  add "-baloon vitio" to qemu command when needed
* tests/qemuhelptest.c: add the new flag for detection

This change makes the 'info chardev' parser ignore any trailing
whitespace on a line. This fixes a specific problem handling a '\r\n'
line ending.

* src/qemu/qemu_monitor_text.c: Ignore trailing whitespace in
  'info chardev' output.

* src/qemu/qemu_driver.c (qemudDomainMigratePrepare2): Remove useless
test of always-non-NULL uri_out parameter.  Use ATTRIBUTE_NONNULL to
inform tools.

* src/qemu/qemu_driver.c (qemudDomainAttachDevice): Call
virCgroupDenyDevicePath only if cgroup is non-NULL.

* src/qemu/qemu_conf.h: Remove QEMU_CMD_FLAG_0_12 and just leave
  the lone JSON flag
* src/qemu/qemu_conf.c: Enable JSON on QEMU 0.13 or later, but
  leave it disabled for now

* src/qemu/qemu_conf.c: CPU models should be probed only if the
  a guest's XML contains CPU model, not each time a qemu command line
  is generated.

The XML XPath for detecting JSON in the running VM statefile was
wrong causing all VMs to get JSON mode enabled at libvirtd restart.

In addition if a VM was running a JSON enabled QEMU once, and then
altered to point to a non-JSON enabled QEMU later the 'monJSON'
flag would not get reset to 0.

* src/qemu/qemu_driver.c: Fix setting/detection of JSON mode

* src/qemu/qemu_driver.c: The 'if' statement is supposed to check return
  value of pci = pciGetDevice(conn, ...); , but check uses if (!dev),
  fix it

Support for memory statistics reporting is accepted for qemu inclusion.
Statistics are reported via the monitor command 'info balloon' as a comma
seprated list:

(qemu) info balloon
balloon: actual=1024,mem_swapped_in=0,mem_swapped_out=0,major_page_faults=88,minor_page_faults=105535,free_mem=1017065472,total_mem=1045229568

Libvirt, qemu, and the guest operating system may support a subset of the
statistics defined by the virtio spec.  Thus, only statistics recognized by
components will be reported.

* src/qemu/qemu_driver.c src/qemu/qemu_monitor_text.[ch]: implement the
  new entry point by using info balloon monitor command

Set up the types for the domainMemoryStats function and insert it into the
virDriver structure definition.  Because of static initializers, update
every driver and set the new field to NULL.

* include/libvirt/libvirt.h.in: new API
* src/driver.h src/*/*_driver.c src/vbox/vbox_tmpl.c: add the new
  entry to the driver structure
* python/generator.py: fix compiler errors, the actual python binding is
  implemented later

* src/qemu/qemu_conf.c src/qemu/qemu_conf.h src/qemu/qemu_driver.c:
  add the new entry point, extend capabilities and code to interract
  with qemu

* src/driver.h: add an extra entry point in the structure
* src/esx/esx_driver.c src/lxc/lxc_driver.c src/opennebula/one_driver.c
  src/openvz/openvz_driver.c src/phyp/phyp_driver.c src/qemu/qemu_driver.c
  src/remote/remote_driver.c src/test/test_driver.c src/uml/uml_driver.c
  src/vbox/vbox_tmpl.c src/xen/xen_driver.c: add NULL entry points for
  all drivers

* src/qemu/qemu_driver.c (doNonTunnelMigrate): Don't let a
NULL "uri_out" provoke a NULL-dereference in doNativeMigrate:
supply omitted goto-after-qemudReportError.

* src/qemu/qemu_driver.c (qemudDomainMigratePrepareTunnel): Upon an
out of memory error, we would end up with unixfile==NULL and attempt
to unlink(NULL).  Skip the unlink when it's NULL.

* src/qemu/qemu_driver.c (qemudDomainMigrateFinish2): Set
"event" to NULL after qemuDomainEventQueue frees it, so a
subsequent free (after endjob label) upon qemuMonitorStartCPUs
failure does not cause a double free.

* src/qemu/qemu_driver.c: #undef LOOKUP_PTYS after use in
  qemudFindCharDevicePTYsMonitor()

If there are no references remaining to the object, vm is set to NULL
and vm->persistent cannot be accessed.  Fixed by this trivial patch.

* src/qemu/qemu_driver.c (qemudDomainCoreDump): Avoid possible
  NULL pointer dereference on --crash dump.

This is trivial for QEMU since you just have to not stop the vm before
starting the dump.  And for Xen, you just pass the flag down to xend.

* include/libvirt/libvirt.h.in (virDomainCoreDumpFlags): Add VIR_DUMP_LIVE.
* src/qemu/qemu_driver.c (qemudDomainCoreDump): Support live dumping.
* src/xen/xend_internal.c (xenDaemonDomainCoreDump): Support live dumping.
* tools/virsh.c (opts_dump): Add --live. (cmdDump): Map it to VIR_DUMP_LIVE.

This patch adds the --crash option (already present in "xm dump-core")
to "virsh dump".  virDomainCoreDump already has a flags argument, so
the API/ABI is untouched.

* include/libvirt/libvirt.h.in (virDomainCoreDumpFlags): New flag for
  CoreDump
* src/test/test_driver.c (testDomainCoreDump): Do not crash
  after dump unless VIR_DUMP_CRASH is given.
* src/qemu/qemu_driver.c (qemudDomainCoreDump): Shutdown the domain
  instead of restarting it if --crash is passed.
* src/xen/xend_internal.c (xenDaemonDomainCoreDump): Support --crash.
* tools/virsh.c (opts_dump): Add --crash.
  (cmdDump): Map it to flags for virDomainCoreDump and pass them.

1) qemuMigrateToCommand uses ">>" so we have to truncate the file
before starting the migration;

2) the command wasn't updated to chown the driver and set/restore
the security lavels;

3) the VM does not have to be resumed if migration fails;

4) the file is not removed when migration fails.

* src/qemu/qemu_driver.c (qemuDomainCoreDump): Truncate file before
  dumping, set/restore ownership and security labels for the file.

Those were pointed by DanB in his review but not yet fixed

* src/qemu/qemu_driver.c: qemudWaitForMonitor() use EnterMonitorWithDriver()
  and ExitMonitorWithDriver() there
* src/qemu/qemu_monitor_text.c: checking fro strdu failure and hash
  table add error in qemuMonitorTextGetPtyPaths()

This change makes the QEMU driver get pty paths from the output of the
monitor 'info chardev' command. This output is structured, and contains
both the name of the device and the path on the same line. This is
considerably more reliable than parsing the startup log output, which
requires the parsing code to know which order QEMU will print pty
information in.

Note that we still need to parse the log output as the monitor itself
may be on a pty. This should be rare, however, and the new code will
replace all pty paths parsed by the log output method once the monitor
is available.

* src/qemu/qemu_monitor.(c|h) src/qemu_monitor_text.(c|h): Implement
  qemuMonitorGetPtyPaths().
* src/qemu/qemu_driver.c: Get pty path information using
  qemuMonitorGetPtyPaths().

* src/qemu/qemu_driver.c: Parse pty devices for channels

Change -monitor, -serial and -parallel output to use -chardev if it is
available.
* src/qemu/qemu_conf.c: Update qemudBuildCommandLine to use -chardev where
  available.
* tests/qemuxml2argvtest.c tests/qemuxml2argvdata/: Add -chardev equivalents
  for all current serial and parallel tests.

Even if qemudStartVMDaemon suceeds, an error was logged such as
'qemuRemoveCgroup:1778 : internal error Unable to find cgroup for'.
This is because qemudStartVMDaemon calls qemuRemoveCgroup to
ensure that old cgroup does not remain. This workaround makes
sense but leaving an error message may confuse users.
* src/qemu/qemu_driver.c: a an option to the function to suppress the
  error being logged

This adds a new flag, VIR_MIGRATE_PAUSED, that mandates pausing
the migrated VM before starting it.

* include/libvirt/libvirt.h.in (virDomainMigrateFlags): Add VIR_MIGRATE_PAUSED.
* src/qemu/qemu_driver.c (qemudDomainMigrateFinish2): Handle VIR_MIGRATE_PAUSED.
* tools/virsh.c (opts_migrate): Add --suspend. (cmdMigrate): Handle it.
* tools/virsh.pod (migrate): Document it.

This makes a small change on the failed-migration path.  Up to now,
all VMs that failed non-live migration after the "stop" command
were restarted.  This must not be done when the VM was paused in
the first place.

* src/qemu/qemu_driver.c (qemudDomainMigratePerform): Do not restart
  a paused VM that fails migration.  Set paused state after "stop",
  reset it after failure.

See also:
https://bugzilla.redhat.com/show_bug.cgi?id=545400#c1

Replace free(virBufferContentAndReset()) with virBufferFreeAndReset().
Update documentation and replace all remaining calls to free() with
calls to VIR_FREE(). Also add missing calls to virBufferFreeAndReset()
and virReportOOMError() in OOM error cases.