This part adds support for qemu making a macvtap tap device available
via file descriptor passed to qemu command line. This also attempts to
tear down the macvtap device when a VM terminates. This includes support
for attachment and detachment to/from running VM.
* src/qemu/qemu_conf.[ch] src/qemu/qemu_driver.c: add support in the
  QEmu driver

Current PCI addresses are allocated at time of VM startup.
To make them truely persistent, it is neccessary to do this
at time of virDomainDefine/virDomainCreate. The code in
qemuStartVMDaemon still remains in order to cope with upgrades
from older libvirt releases

* src/qemu/qemu_driver.c: Rename existing qemuAssignPCIAddresses
  to qemuDetectPCIAddresses. Add new qemuAssignPCIAddresses which
  does auto-allocation upfront. Call qemuAssignPCIAddresses from
  qemuDomainDefine and qemuDomainCreate to assign PCI addresses that
  can then be persisted. Don't clear PCI addresses at shutdown if
  they are intended to be persistent

The old text mode monitor prompts for a password when disks are
encrypted. This interactive approach doesn't work for JSON mode
monitor. Thus there is a new 'block_passwd' command that can be
used.

* src/qemu/qemu_driver.c: Split out code for looking up a disk
  secret from findVolumeQcowPassphrase, into a new method
  getVolumeQcowPassphrase. Enhance qemuInitPasswords() to also
  set the disk encryption password via the monitor
* 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
  support for the 'block_passwd' monitor command.

Since c26cb923, the dname
parameter has been ignored by these two functions.  Use it.
* src/qemu/qemu_driver.c (qemudDomainMigratePrepareTunnel): Honor dname
parameter once again.
(qemudDomainMigratePrepare2): Likewise.

Currently the timeout for reading startup output is 3 seconds. If the
host is under any sort of load, we can easily trigger this. Lets bump
it to 30 seconds.

Since the polling loop checks to see if the process has died, we shouldn't
erroneously hit this timeout if qemu bombs (only if it is stuck in some
infinite loop).

The timeout errors were unconditionally being overwritten by the less
helpful 'unable to start guest' error.

The virConnectPtr is no longer required for error reporting since
that is recorded in a thread local. Remove use of virConnectPtr
from all APIs in cpu_conf.{h,c} and update all callers to
match

The virConnectPtr is no longer required for error reporting since
that is recorded in a thread local. Remove use of virConnectPtr
from all APIs in node_device_conf.{h,c} and update all callers to
match

The QEMU flags are commonly stored as a signed or unsigned int,
allowing only 31 flags. This limit is rather close, so to aid
future patches, change it to a 64-bit int

* src/qemu/qemu_conf.c, src/qemu/qemu_conf.h, src/qemu/qemu_driver.c,
  tests/qemuargv2xmltest.c, tests/qemuhelptest.c, tests/qemuxml2argvtest.c:
  Use 'unsigned long long' for QEMU flags

The virConnectPtr is no longer required for error reporting since
that is recorded in a thread local. Remove use of virConnectPtr
from all APIs in security_driver.{h,c} and update all callers to
match

The security driver was mistakenly initialized before the QEMU
config file was loaded. This prevents it being turned off again.
The capabilities XML was also getting the wrong security driver
name, due to the stacked driver arrangement.

* src/qemu/qemu_driver.c: Fix initialization order and capabilities
  model name

It was used for error reporting only.

It was used for error reporting only.

It was used for error reporting only.

It was used for error reporting only.

Implementation of domain{Attach,Detach}DeviceFlags handlers
in the drivers.

If the primary security driver (SELinux/AppArmour) was disabled
then the secondary QEMU DAC security driver was also disabled.
This is mistaken, because the latter must be active at all times

* src/qemu/qemu_driver.c: Ensure DAC driver is always active

To allow devices to be hot(un-)plugged it is neccessary to ensure
they all have a unique device aliases. This fixes the hotplug
methods to assign device aliases before invoking the monitor
commands which need them

* src/qemu/qemu_conf.c, src/qemu/qemu_conf.h: Expose methods
  for assigning device aliases for disks, host devices and
  controllers
* src/qemu/qemu_driver.c: Assign device aliases when hotplugging
  all types of device
* tests/qemuxml2argvdata/qemuxml2argv-hostdev-pci-address-device.args,
  tests/qemuxml2argvdata/qemuxml2argv-hostdev-usb-address-device.args:
  Update for changed hostdev naming scheme

This patch re-arranges the QEMU device alias assignment code to
make it easier to call into the same codeblock when performing
device hotplug. The new code has the ability to skip over already
assigned names to facilitate hotplug

* src/qemu/qemu_driver.c: Call qemuAssignDeviceNetAlias()
  instead of qemuAssignNetNames
* src/qemu/qemu_conf.h: Export qemuAssignDeviceNetAlias()
  instead of qemuAssignNetNames
* src/qemu/qemu_driver.c: Merge the legacy disk/network alias
  assignment code into the main methods

The current way of assigning names to the host network backend and
NIC device in QEMU was over complicated, by varying naming scheme
based on the NIC model and backend type. This simplifies the naming
to simply be 'net0' and 'hostnet0', allowing code to easily determine
the host network name and vlan based off the primary device alias
name 'net0'. This in turn allows removal of alot of QEMU specific
code from the XML parser, and makes it easier to assign new unique
names for NICs that are hotplugged

* src/conf/domain_conf.c, src/conf/domain_conf.h: Remove hostnet_name
  and vlan fields from virNetworkDefPtr
* src/qemu/qemu_conf.c, src/qemu/qemu_conf.h, src/qemu/qemu_driver.c:
  Use a single network alias naming scheme regardless of NIC type
  or backend type. Determine VLANs from the alias name.
* tests/qemuxml2argvdata/qemuxml2argv-net-eth-names.args,
  tests/qemuxml2argvdata/qemuxml2argv-net-virtio-device.args,
  tests/qemuxml2argvdata/qemuxml2argv-net-virtio-netdev.args: Update
  for new simpler naming scheme

PCI disk, disk controllers, net devices and host devices need to
have PCI addresses assigned before they are hot-plugged

* src/qemu/qemu_conf.c: Add APIs for ensuring a device has an
  address and releasing unused addresses
* src/qemu/qemu_driver.c: Ensure all devices have addresses
  when hotplugging.

The current QEMU code allocates PCI addresses incrementally starting
at 4. This is not satisfactory because the user may have given some
addresses in their XML config, which need to be skipped over when
allocating addresses to remaining devices.

It is thus neccessary to maintain a list of already allocated PCI
addresses and then only allocate ones that remain unused. This is
also required for domain device hotplug to work properly later.

* src/qemu/qemu_conf.c, src/qemu/qemu_conf.h: Add APIs for creating
  list of existing PCI addresses, and allocating new addresses.
  Refactor address assignment to use this code
* src/qemu/qemu_driver.c: Pull PCI address assignment up into the
  qemuStartVMDaemon() method, as a prelude to moving it into the
  'define' method. Update list of allocated addresses when connecting
  to a running VM at daemon startup.
* tests/qemuxml2argvtest.c, tests/qemuargv2xmltest.c,
  tests/qemuxml2xmltest.c: Remove USB product test since all
  passthrough is done based on address
* tests/qemuxml2argvdata/qemuxml2argv-hostdev-usb-product.args,
  tests/qemuxml2argvdata/qemuxml2argv-hostdev-usb-product.xml: Kil
  unused data files

Since QEMU startup uses the new -device argument, the hotplug
code needs todo the same. This converts disk, network and
host device hotplug to use the device_add command

* src/qemu/qemu_driver.c: Use new device_add monitor APIs
  whereever possible

All the helper functions for building command line arguments
now return a 'char *', instead of acepting a 'char **' or
virBufferPtr argument

* qemu/qemu_conf.c: Standardize syntax for building args
* qemu/qemu_conf.h: Export all functions for building args
* qemu/qemu_driver.c: Update for changed syntax for building
  NIC/hostnet args

* src/qemu/qemu_driver.c (qemudLogReadFD): Don't pass a negative
offset (from a preceding failed attempt to seek to EOF) to this use
of lseek.

Similar to the race fixed by
be34c3c7, make sure
to wait around for KVM to release the resources from
a hot-detached PCI device before attempting to
rebind that device to the host driver.
Signed-off-by: NChris Lalancette <clalance@redhat.com>

If you shutdown libvirtd while a domain with PCI
devices is running, then try to restart libvirtd,
libvirtd will crash.

This happens because qemuUpdateActivePciHostdevs() is calling
pciDeviceListSteal() with a dev of 0x0 (NULL), and then trying
to dereference it.  This patch fixes it up so that
qemuUpdateActivePciHostdevs() steals the devices after first
Get()'ting them, avoiding the crash.
Signed-off-by: NChris Lalancette <clalance@redhat.com>

Certain hypervisors (like qemu/kvm) map the PCI bar(s) on
the host when doing device passthrough.  This can lead to a race
condition where the hypervisor is still cleaning up the device while
libvirt is trying to re-attach it to the host device driver.  To avoid
this situation, we look through /proc/iomem, and if the hypervisor is
still holding onto the bar (denoted by the string in the matcher variable),
then we can wait around a bit for that to clear up.

v2: Thanks to review by DV, make sure we wait the full timeout per-device
Signed-off-by: NChris Lalancette <clalance@redhat.com>

The loop looking for the controller associated with a SCI drive had
an off by one, causing it to miss the last controller.

* src/qemu/qemu_driver.c: Fix off-by-1 in searching for SCSI
  drive hotplug

The hotplug code in QEMU was leaking memory because although the
inner device object was being moved into the main virDomainDefPtr
config object, the outer container virDomainDeviceDefPtr was not.

 * src/qemu/qemu_driver.c: Clarify code to show that the inner
   device object is owned by the main domain config upon
   successfull attach.

The hotplug code was not correctly invoking the security driver
in error paths. If a hotplug attempt failed, the device would
be left with VM permissions applied, rather than restored to the
original permissions. Also, a CDROM media that is ejected was
not restored to original permissions. Finally there was a bogus
call to set hostdev permissions in the hostdev unplug code

* qemu/qemu_driver.c: Fix security driver usage in hotplug/unplug

If there is a problem with VM startup, PCI devices may be left
assigned to pci-stub / pci-back. Adding a call to reattach
host devices in the cleanup path is required.

* qemu/qemu_driver.c: qemuDomainReAttachHostDevices() when
  VM startup fails

Remove all the QEMU driver calls for setting file ownership and
process uid/gid. Instead wire in the QEMU DAC security driver,
stacking it ontop of the primary SELinux/AppArmour driver.

* qemu/qemu_driver.c: Switch over to new DAC security driver

Pulling the disk labelling code out of the exec hook, and into
libvirtd will allow it to access shared state in the daemon. It
will also make debugging & error reporting easier / more reliable.

* qemu/qemu_driver.c: Move initial disk labelling calls up into
  libvirtd. Add cleanup of disk labels upon failure