Commit 1b1402b9 introduced a regression.  Since older libvirt versions
would silently round memory up (until the previous patch), but populated
current memory based on querying the guest, it was possible to have
dumpxml show cur > max by the amount of the rounding.  For example, if
a user requested 1048570 KiB memory (just shy of 1GiB), the qemu
driver would actually run with 1048576 KiB, and libvirt 0.9.10 would
output a current that was 6KiB larger than the maximum.  Situations
where this could have an impact include, but are not limited to,
migration from old to new libvirt, managedsave in old libvirt and
start in new libvirt, snapshot creation in old libvirt and revert in
new libvirt - without this patch, the new libvirt would reject the
VM because of the rounding discrepancy.

Fix things by adding a fuzz factor, and silently clamp current down to
maximum in that case, rather than failing to reparse XML for an existing
VM.  From a practical standpoint, this has no user impact: 'virsh
dumpxml' will continue to query the running guest rather than rely on
the incoming xml, which will see the currect current value, and even if
clamping down occurs during parsing, it will be by at most the fuzz
factor of a megabyte alignment, and rounded back up when passed back to
the hypervisor.

Meanwhile, we continue to reject cur > max if the difference is beyond
the fuzz factor of nearest megabyte.  But this is not a real change in
behavior, since with 0.9.10, even though the parser allowed it, later
in the processing stream we would reject it at the qemu layer; so
rejecting it in the parser just moves error detection to a nicer place.

* src/conf/domain_conf.c (virDomainDefParseXML): Don't reject
existing XML.
Based on a report by Zhou Peng.

This patch reverts commit b0e2bb33. Its functionality has been replaced
by commit 3269ee65.

* src/conf/domain_conf.c (virDomainChannelDefCheckABIStability): avoid
  crashing libvirtd due to derefing a NULL pointer.

For details, please see bug:
RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=808371Signed-off-by: NAlex Jia <ajia@redhat.com>

libvirt documentation for channels with type 'spicevmc' says that the
'target' child node has:
"an optional attribute name controls how the guest will have access
 to the channel, and defaults to name='com.redhat.spice.0'."

However, this default value is never set in libvirt code base,
there's only a check in qemu_command.c to error out if the name
attribute doesn't have the expected value (if it's set).

This commit sets a default target name for spicevmc channels during
the domain configuration parsing so that the code agrees with the
documentation.

Pass argv to the init binary of LXC, using a new <initarg> element.

* docs/formatdomain.html.in: Document <os> usage for containers
* docs/schemas/domaincommon.rng: Add <initarg> element
* src/conf/domain_conf.c, src/conf/domain_conf.h: parsing and
  formatting of <initarg>
* src/lxc/lxc_container.c: Setup LXC argv
* tests/Makefile.am, tests/lxcxml2xmldata/lxc-systemd.xml,
  tests/lxcxml2xmltest.c, tests/testutilslxc.c,
  tests/testutilslxc.h: Test parsing/formatting of LXC related
  XML parts

Return statements with parameter enclosed in parentheses were modified
and parentheses were removed. The whole change was scripted, here is how:

List of files was obtained using this command:
git grep -l -e '\<return\s*([^()]*\(([^()]*)[^()]*\)*)\s*;' |             \
grep -e '\.[ch]$' -e '\.py$'

Found files were modified with this command:
sed -i -e                                                                 \
's_^\(.*\<return\)\s*(\(\([^()]*([^()]*)[^()]*\)*\))\s*\(;.*$\)_\1 \2\4_' \
-e 's_^\(.*\<return\)\s*(\([^()]*\))\s*\(;.*$\)_\1 \2\3_'

Then checked for nonsense.

The whole command looks like this:
git grep -l -e '\<return\s*([^()]*\(([^()]*)[^()]*\)*)\s*;' |             \
grep -e '\.[ch]$' -e '\.py$' | xargs sed -i -e                            \
's_^\(.*\<return\)\s*(\(\([^()]*([^()]*)[^()]*\)*\))\s*\(;.*$\)_\1 \2\4_' \
-e 's_^\(.*\<return\)\s*(\([^()]*\))\s*\(;.*$\)_\1 \2\3_'

This introduces a new domain state pmsuspended to represent
the domain which has been suspended by guest power management,
e.g. (entered itno s3 state). Because a "running" state could
be confused in this case, one will see the guest is paused
actually while playing. And state "paused" is for the domain
which was paused by virDomainSuspend.

The "tray" is only allowed for removable disks, i.e. CDROM and
Floppy disks.

A few times libvirt users manually setting mac addresses have
complained of a networking failure that ends up being due to a multicast
mac address being used for a guest interface. This patch prevents that
by logging an error and failing if a multicast mac address is
encountered in each of the three following cases:

1) domain xml <interface> mac address.
2) network xml bridge mac address.
3) network xml dhcp/host mac address.

There are several other places where a mac address can be input that
aren't controlled in this manner because failure to do so has no
consequences (e.g., if the address will be used to search through
existing interfaces for a match).

The RNG has been updated to add multiMacAddr and uniMacAddr along with
the existing macAddr, and macAddr was switched to uniMacAddr where
appropriate.

If no <interface> elements are included in an LXC guest XML
description, then the LXC guest will just see the host's
network interfaces. It is desirable to be able to hide the
host interfaces, without having to define any guest interfaces.

This patch introduces a new feature flag <privnet/> to allow
forcing of a private network namespace for LXC. In the future
I also anticipate that we will add <privuser/> to force a
private user ID namespace.

* src/conf/domain_conf.c, src/conf/domain_conf.h: Add support
  for <privnet/> feature. Auto-set <privnet> if any <interface>
  devices are defined
* src/lxc/lxc_container.c: Honour request for private network
  namespace

numad is an user-level daemon that monitors NUMA topology and
processes resource consumption to facilitate good NUMA resource
alignment of applications/virtual machines to improve performance
and minimize cost of remote memory latencies. It provides a
pre-placement advisory interface, so significant processes can
be pre-bound to nodes with sufficient available resources.

More details: http://fedoraproject.org/wiki/Features/numad

"numad -w ncpus:memory_amount" is the advisory interface numad
provides currently.

This patch add the support by introducing a new XML attribute
for <vcpu>. e.g.

  <vcpu placement="auto">4</vcpu>
  <vcpu placement="static" cpuset="1-10^6">4</vcpu>

The returned advisory nodeset from numad will be printed
in domain's dumped XML. e.g.
  <vcpu placement="auto" cpuset="1-10^6">4</vcpu>

If placement is "auto", the number of vcpus and the current
memory amount specified in domain XML will be used for numad
command line (numad uses MB for memory amount):
  numad -w $num_of_vcpus:$current_memory_amount / 1024

The advisory nodeset returned from numad will be used to set
domain process CPU affinity then. (e.g. qemuProcessInitCpuAffinity).

If the user specifies both CPU affinity policy (e.g.
(<vcpu cpuset="1-10,^7,^8">4</vcpu>) and placement == "auto"
the specified CPU affinity will be overridden.

Only QEMU/KVM drivers support it now.

See docs update in patch for more details.

Even though we say in documentation setting (tls-)port to -1 is legacy
compat style for enabling autoport, we're roughly doing this for VNC.
However, in case of SPICE auto enable autoport iff both port & tlsPort
are equal -1 as documentation says autoport plays with both.

When host-model and host-passthrouh CPU modes were introduced, qemu
driver was properly modify to update guest CPU definition during
migration so that we use the right CPU at the destination. However,
similar treatment is needed for (managed)save and snapshots since they
need to save the exact CPU so that a domain can be properly restored.
To avoid repetition of such situation, all places that need live XML
share the code which generates it.

As a side effect, this patch fixes error reporting from
qemuDomainSnapshotWriteMetadata().

spice agent-mouse support

Usage:
  <graphics type='spice'>
    <mouse mode='client'|'server'/>
  <graphics/>
Signed-off-by: NOsier Yang <jyang@redhat.com>

There are several functions in domain_conf.c that remove a device
object from the domain's list of that object type, but don't free the
object or return it to the caller to free. In many cases this isn't a
problem because the caller already had a pointer to the object and
frees it afterward, but in several cases the removed object was just
left floating around with no references to it.

In particular, the function qemuDomainDetachDeviceConfig() calls
functions to locate and remove net (virDomainNetRemoveByMac), disk
(virDomainDiskRemoveByName()), and lease (virDomainLeaseRemove())
devices, but neither it nor its caller qemuDomainModifyDeviceConfig()
ever obtain a pointer to the device being removed, much less free it.

This patch modifies the following "remove" functions to return a
pointer to the device object being removed from the domain device
arrays, to give the caller the option of freeing the device object
using that pointer if needed. In places where the object was
previously leaked, it is now freed:

  virDomainDiskRemove
  virDomainDiskRemoveByName
  virDomainNetRemove
  virDomainNetRemoveByMac
  virDomainHostdevRemove
  virDomainLeaseRemove
  virDomainLeaseRemoveAt

The functions that had been leaking:

  libxlDomainDetachConfig - leaked a virDomainDiskDef
  qemuDomainDetachDeviceConfig - could leak a virDomainDiskDef,
                            a virDomainNetDef, or a
                            virDomainLeaseDef
  qemuDomainDetachLease   - leaked a virDomainLeaseDef

It will be used in a different file in an upcoming patch.

Some members are generated during XML parse (e.g. MAC address of
an interface); However, with current implementation, if we
are plugging a device both to persistent and live config,
we parse given XML twice: first time for live, second for config.
This is wrong then as the second time we are not guaranteed
to generate same values as we did for the first time.
To prevent that we need to create a copy of DeviceDefPtr;
This is done through format/parse process instead of writing
functions for deep copy as it is easier to maintain:
adding new field to any virDomain*DefPtr doesn't require change
of copying function.

Output is still in kibibytes, but input can now be in different
scales for ease of typing.

* src/conf/domain_conf.c (virDomainParseMemory): New helper.
(virDomainDefParseXML): Use it when parsing.
* docs/schemas/domaincommon.rng: Expand XML; rename memoryKBElement
to memoryElement and update callers.
* docs/formatdomain.html.in (elementsMemoryAllocation): Document
scaling.
* tests/qemuxml2argvdata/qemuxml2argv-memtune.xml: Adjust test.
* tests/qemuxml2xmltest.c: Likewise.
* tests/qemuxml2xmloutdata/qemuxml2xmlout-memtune.xml: New file.

Using 'unsigned long' for memory values is risky on 32-bit platforms,
as a PAE guest can have more than 4GiB memory.  Our API is
(unfortunately) locked at 'unsigned long' and a scale of 1024, but
the rest of our system should consistently use 64-bit values,
especially since the previous patch centralized overflow checking.

* src/conf/domain_conf.h (_virDomainDef): Always use 64-bit values
for memory.  Change hugepage_backed to a bool.
* src/conf/domain_conf.c (virDomainDefParseXML)
(virDomainDefCheckABIStability, virDomainDefFormatInternal): Fix
clients.
* src/vmx/vmx.c (virVMXFormatConfig): Likewise.
* src/xenxs/xen_sxpr.c (xenParseSxpr, xenFormatSxpr): Likewise.
* src/xenxs/xen_xm.c (xenXMConfigGetULongLong): New function.
(xenXMConfigGetULong, xenXMConfigSetInt): Avoid truncation.
(xenParseXM, xenFormatXM): Fix clients.
* src/phyp/phyp_driver.c (phypBuildLpar): Likewise.
* src/openvz/openvz_driver.c (openvzDomainSetMemoryInternal):
Likewise.
* src/vbox/vbox_tmpl.c (vboxDomainDefineXML): Likewise.
* src/qemu/qemu_command.c (qemuBuildCommandLine): Likewise.
* src/qemu/qemu_process.c (qemuProcessStart): Likewise.
* src/qemu/qemu_monitor.h (qemuMonitorGetBalloonInfo): Likewise.
* src/qemu/qemu_monitor_text.h (qemuMonitorTextGetBalloonInfo):
Likewise.
* src/qemu/qemu_monitor_text.c (qemuMonitorTextGetBalloonInfo):
Likewise.
* src/qemu/qemu_monitor_json.h (qemuMonitorJSONGetBalloonInfo):
Likewise.
* src/qemu/qemu_monitor_json.c (qemuMonitorJSONGetBalloonInfo):
Likewise.
* src/qemu/qemu_driver.c (qemudDomainGetInfo)
(qemuDomainGetXMLDesc): Likewise.
* src/uml/uml_conf.c (umlBuildCommandLine): Likewise.

The test domain allows <memory>0</memory>, but the RNG was stating
that memory had to be at least 4096000 bytes.  Hypervisors should
enforce their own limits, rather than complicating the RNG.

Meanwhile, some copy and paste had introduced some fishy constructs
in various unit tests.

* docs/schemas/domaincommon.rng (memoryKB, memoryKBElement): Drop
limit that isn't enforced in code.
* src/conf/domain_conf.c (virDomainDefParseXML): Require current
<= maximum.
* tests/qemuxml2argvdata/*.xml: Fix offenders.

Make it obvious to 'dumpxml' readers what unit we are using,
since our default of KiB for memory (1024) differs from qemu's
default of MiB; and differs from our use of bytes for storage.

Tests were updated via:

$ find tests/*data tests/*out -name '*.xml' | \
  xargs sed -i 's/<\(memory\|currentMemory\|hard_limit\|soft_limit\|min_guarantee\|swap_hard_limit\)>/<\1 unit='"'KiB'>/"
$ find tests/*data tests/*out -name '*.xml' | \
  xargs sed -i 's/<\(capacity\|allocation\|available\)>/<\1 unit='"'bytes'>/"

followed by a few fixes for the stragglers.

Note that with this patch, the RNG for <memory> still forbids
validation of anything except unit='KiB', since the code silently
ignores the attribute; a later patch will expand <memory> to allow
scaled input in the code and update the RNG to match.

* docs/schemas/basictypes.rng (unit): Add 'bytes'.
(scaledInteger): New define.
* docs/schemas/storagevol.rng (sizing): Use it.
* docs/schemas/storagepool.rng (sizing): Likewise.
* docs/schemas/domaincommon.rng (memoryKBElement): New define; use
for memory elements.
* src/conf/storage_conf.c (virStoragePoolDefFormat)
(virStorageVolDefFormat): Likewise.
* src/conf/domain_conf.h (_virDomainDef): Document unit used
internally.
* src/conf/storage_conf.h (_virStoragePoolDef, _virStorageVolDef):
Likewise.
* tests/*data/*.xml: Update all tests.
* tests/*out/*.xml: Likewise.
* tests/define-dev-segfault: Likewise.
* tests/openvzutilstest.c (testReadNetworkConf): Likewise.
* tests/qemuargv2xmltest.c (blankProblemElements): Likewise.

This exact code is duplicated in qemuDomainDetachNetDevice().

This patch makes sure that each network device ("interface") of
type='hostdev' appears on both the hostdevs list and the nets list of
the virDomainDef, and it modifies the qemu driver startup code so that
these devices will be presented to qemu on the commandline as hostdevs
rather than as network devices.

It does not add support for hotplug of these type of devices, or code
to honor the <mac address> or <virtualport> given in the config (both
of those will be done in separate patches).

Once each device is placed on both lists, much of what this patch does
is modify places in the code that traverse all the device lists so
that these hybrid devices are only acted on once - either along with
the other hostdevs, or along with the other network interfaces. (In
many cases, only one of the lists is traversed / a specific operation
is performed on only one type of device. In those instances, the code
can remain unchanged.)

There is one special case - when building the commandline, interfaces
are allowed to proceed all the way through
networkAllocateActualDevice() before deciding to skip the rest of
netdev-specific processing - this is so that (once we have support for
networks with pools of hostdev devices) we can get the actual device
allocated, then rely on the loop processing all hostdevs to generate
the correct commandline.

(NB: <interface type='hostdev'> is only supported for PCI network
devices that are SR-IOV Virtual Functions (VF). Standard PCI[e] and
USB devices, and even the Physical Functions (PF) of SR-IOV devices
can only be assigned to a guest using the more basic <hostdev> device
entry. This limitation is mostly due to the fact that non-SR-IOV
ethernet devices tend to lose mac address configuration whenever the
card is reset, which happens when a card is assigned to a guest;
SR-IOV VFs fortunately don't suffer the same problem.)

This is the new interface type that sets up an SR-IOV PCI network
device to be assigned to the guest with PCI passthrough after
initializing some network device-specific things from the config
(e.g. MAC address, virtualport profile parameters). Here is an example
of the syntax:

  <interface type='hostdev' managed='yes'>
    <source>
      <address type='pci' domain='0' bus='0' slot='4' function='3'/>
    </source>
    <mac address='00:11:22:33:44:55'/>
    <address type='pci' domain='0' bus='0' slot='7' function='0'/>
  </interface>

This would assign the PCI card from bus 0 slot 4 function 3 on the
host, to bus 0 slot 7 function 0 on the guest, but would first set the
MAC address of the card to 00:11:22:33:44:55.

NB: The parser and formatter don't care if the PCI card being
specified is a standard single function network adapter, or a virtual
function (VF) of an SR-IOV capable network adapter, but the upcoming
code that implements the back end of this config will work *only* with
SR-IOV VFs. This is because modifying the mac address of a standard
network adapter prior to assigning it to a guest is pointless - part
of the device reset that occurs during that process will reset the MAC
address to the value programmed into the card's firmware.

Although it's not supported by any of libvirt's hypervisor drivers,
usb network hostdevs are also supported in the parser and formatter
for completeness and consistency. <source> syntax is identical to that
for plain <hostdev> devices, except that the <address> element should
have "type='usb'" added if bus/device are specified:

  <interface type='hostdev'>
    <source>
      <address type='usb' bus='0' device='4'/>
    </source>
    <mac address='00:11:22:33:44:55'/>
  </interface>

If the vendor/product form of usb specification is used, type='usb'
is implied:

  <interface type='hostdev'>
    <source>
      <vendor id='0x0012'/>
      <product id='0x24dd'/>
    </source>
    <mac address='00:11:22:33:44:55'/>
  </interface>

Again, the upcoming patch to fill in the backend of this functionality
will log an error and fail with "Unsupported Config" if you actually
try to assign a USB network adapter to a guest using <interface
type='hostdev'> - just use a standard <hostdev> entry in that case
(and also for single-port PCI adapters).

Three new functions useful in other files:

virDomainHostdevInsert:

Add a new hostdev at the end of the array. This would more sensibly be
called virDomainHostdevAppend, but the existing functions for other
types of devices are called Insert.

virDomainHostdevRemove:

Eliminates one entry from the hostdevs array, but doesn't free it;
patterned after the code at the end of the two
qemuDomainDetachHostXXXDevice functions (and also other pre-existing
virDomainXXXRemove functions for other device types).

virDomainHostdevFind:

This function is patterned from the search loops at the top of
qemuDomainDetachHostPciDevice and qemuDomainDetachHostUsbDevice, and
will be used to re-factor those (and other detach-related) functions.

The parent can be any type of device. It defaults to type=none, and a
NULL pointer. The intent is that if a hostdevdef is contained in the
def for a higher level device (e.g. virDomainNetDef), hostdev->parent
will point to the higher level device, and type will be set to that
type of device. This way, during attach and detach of the device,
parent can be checked, and appropriate callouts made to do higher
level device initialization (e.g. setting MAC address).

Also, although these hostdevs with parents will be added to a domain's
hostdevs list, they will be treated slightly differently when
traversing the list, e.g. virDomainHostdefDefFree for a hostdev that
has a parent doesn't need to be called (and will be a NOP); it will
simply be removed from the list (since the parent device object is in
its own type-specific list, and will be freed from there).

In an upcoming patch, virDomainNetDef will acquire a
virDomainHostdevDef, and the <interface> XML will take on some of the
elements of a <hostdev>. To avoid duplicating the code for parsing and
formatting the <source> element (which will be nearly identical in
these two cases), this patch factors those parts out of the
HostdevDef's parse and format functions, and puts them into separate
helper functions that are now called by the HostdevDef
parser/formatter, and will soon be called by the NetDef
parser/formatter.

One change in behavior - previously virDomainHostdevDefParseXML() had
diverged from current common coding practice by logging an error and
failing if it found any subelements of <hostdev> other than those it
understood (standard libvirt practice is to ignore/discard unknown
elements and attributes during parse). The new helper function ignores
unknown elements, and thus so does the new
virDomainHostdevDefParseXML.

In order to allow for a virDomainHostdevDef that uses the
virDomainDeviceInfo of a "higher level" device (such as a
virDomainNetDef), this patch changes the virDomainDeviceInfo in the
HostdevDef into a virDomainDeviceInfoPtr. Rather than adding checks
all over the code to check for a null info, we just guarantee that it
is always valid. The new function virDomainHostdevDefAlloc() allocates
a virDomainDeviceInfo and plugs it in, and virDomainHostdevDefFree()
makes sure it is freed.

There were 4 places allocating virDomainHostdevDefs, all of them
parsers of one sort or another, and those have all had their
VIR_ALLOC(hostdev) changed to virDomainHostdevDefAlloc(). Other than
that, and the new functions, all the rest of the changes are just
mechanical removals of "&" or changing "." to "->".

There will be cases where the iterator callback will need to know the
type of the device whose info is being operated on, and possibly even
need to use some of the device's config. This patch adds a
virDomainDeviceDefPtr to the args of every callback, and fills it in
appropriately as the devices are iterated through.

No code change, movement only.  This is necessary to eliminate forward
references.

Not all device types were represented in virDomainDeviceType, so some
types of devices couldn't be represented in a virDomainDeviceDef
(which requires a different type of pointer in the union for each
different kind of device).

Since serial, parallel, channel, and console devices are all
virDomainChrDef, and the virDomainDeviceType is never used to produce
a string from the type (and only used in the other direction
internally to code, never to produce XML), I only added one "CHR"
type, which is associated with "virDomainChrDefPtr chr" in the union.

* src/conf/domain_conf.h: Add new member "target" to struct
  _virDomainDeviceDriveAddress.

* src/conf/domain_conf.c: Parse and format "target"

* Lots of tests (.xml) in tests/domainsnapshotxml2xmlout,
  tests/qemuxml2argvdata, tests/qemuxml2xmloutdata, and
  tests/vmx2xmldata/ are modified for newly introduced
  attribute "target" for address of "drive" type.

Adding a new model for virtio-scsi roughly follows the same scheme
as the previous patch.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

KVM will be able to use a PCI SCSI controller even on POWER.  Let
the user specify the vSCSI controller by other means than a default.

After this patch, the QEMU driver will actually look at the model
and reject anything but auto, lsilogic and ibmvscsi.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NOsier Yang <jyang@redhat.com>

Previously we would have:

"os type 'hvm' & arch 'idontexist' combination is not supported"

Now we get

"No guest options available for arch 'idontexist'"

or if options available but guest OS type not applicable:

"No os type 'xen' available for arch 'x86_64'"

Bug introduced in commit 35abced2.  On an inactive domain,
$ virsh snapshot-create-as dom snap
$ virsh snapshot-create dom
$ virsh snapshot-create dom
$ virsh snapshot-delete --children dom snap
could crash libvirtd, due to a use-after-free that results
when the callback freed the current element in the iteration.

* src/conf/domain_conf.c (virDomainSnapshotForEachChild)
(virDomainSnapshotActOnDescendant): Allow iteration to delete
current child.

This patch allows libvirt to add interfaces to already
existing Open vSwitch bridges. The following syntax in
domain XML file can be used:

    <interface type='bridge'>
      <mac address='52:54:00:d0:3f:f2'/>
      <source bridge='ovsbr'/>
      <virtualport type='openvswitch'>
        <parameters interfaceid='921a80cd-e6de-5a2e-db9c-ab27f15a6e1d'/>
      </virtualport>
      <address type='pci' domain='0x0000' bus='0x00'
                          slot='0x03' function='0x0'/>
    </interface>

or if libvirt should auto-generate the interfaceid use
following syntax:

    <interface type='bridge'>
      <mac address='52:54:00:d0:3f:f2'/>
      <source bridge='ovsbr'/>
      <virtualport type='openvswitch'>
      </virtualport>
      <address type='pci' domain='0x0000' bus='0x00'
                          slot='0x03' function='0x0'/>
    </interface>

It is also possible to pass an optional profileid. To do that
use following syntax:

   <interface type='bridge'>
     <source bridge='ovsbr'/>
     <mac address='00:55:1a:65:a2:8d'/>
     <virtualport type='openvswitch'>
       <parameters interfaceid='921a80cd-e6de-5a2e-db9c-ab27f15a6e1d'
                   profileid='test-profile'/>
     </virtualport>
   </interface>

To create Open vSwitch bridge install Open vSwitch and
run the following command:

    ovs-vsctl add-br ovsbr

An upcoming patch will add a <virtualport> element to interfaces of
type='bridge', so it makes sense to give this function a more generic
name.

This reverts commit 7b345b69.

Conflicts:

	tests/qemuxml2argvdata/qemuxml2argv-disk-scsi-vscsi.xml