Commit 498d783 cleans up some of virtual file names for parsing strings
in memory. This patch cleans up (hopefuly) the rest forgotten by the
first patch.
This patch also changes all of the previously modified "filenames" to
valid URI's replacing spaces for underscores.
Changes to v1:
- Replace all spaces for underscores, so that the strings form valid
URI's
- Replace spaces in places changed by commit 498d783
While parsing XML strings from memory, the previous convention in
libvirt was to set the virtual file name to "domain.xml" or something
similar. This could potentialy trick the user into looking for a file
named domain.xml on the disk in an attempt to fix the error.
This patch changes these filenames to something that can't be as easily
confused for a valid filename.
Examples of error messages:
---------------------------
Error while loading file from disk:
15:07:59.015: 527: error : catchXMLError:709 : /path/to/domain.xml:1: StartTag: invalid element name
<domain type='kvm'><
--------------------^
Error while parsing definition in memory:
15:08:43.581: 525: error : catchXMLError:709 : (domain definition):2: error parsing attribute name
<name>vm1</name>
--^
Regression introduced in commit d6f6b2d194c. Running
'virsh snapshot-create dom' would mistakenly report that
disks can only be specified for disk snapshots.
* src/conf/domain_conf.c (virDomainSnapshotDefParseString): Only
give error about no disk support when <disk> was found.
A new element is introduced to XML that allows to control
state of virtual network interfaces in hypervisors.
Live modification of the link state allows networking tools
propagate topology changes to guest OS or testing of
scenarios in complex (virtual) networks.
This patch adds elements to XML grammars and parsing and generating
code.
It is important to be able to attach USB redirected devices to a
particular controller (one that supports USB2 for instance).
Without this patch, only the default bus was used.
<redirdev bus='usb' type='spicevmc'>
<address type='usb' bus='0' port='4'/>
</redirdev>
Snapshots alter the set of disk image files opened by qemu, so
they must be audited. But they don't involve a full disk definition
structure, just the new filename. Make the next patch easier by
refactoring the audit routines to just operate on file name.
* src/conf/domain_audit.h (virDomainAuditDisk): Update prototype.
* src/conf/domain_audit.c (virDomainAuditDisk): Act on strings,
not definition structures.
(virDomainAuditStart): Update caller.
* src/qemu/qemu_hotplug.c (qemuDomainChangeEjectableMedia)
(qemuDomainAttachPciDiskDevice, qemuDomainAttachSCSIDisk)
(qemuDomainAttachUsbMassstorageDevice)
(qemuDomainDetachPciDiskDevice, qemuDomainDetachDiskDevice):
Likewise.
I got confused when 'virsh domblkinfo dom disk' required the
path to a disk (which can be ambiguous, since a single file
can back multiple disks), rather than the unambiguous target
device name that I was using in disk snapshots. So, in true
developer fashion, I went for the best of both worlds - all
interfaces that operate on a disk (aka block) now accept
either the target name or the unambiguous path to the backing
file used by the disk.
* src/conf/domain_conf.h (virDomainDiskIndexByName): Add
parameter.
(virDomainDiskPathByName): New prototype.
* src/libvirt_private.syms (domain_conf.h): Export it.
* src/conf/domain_conf.c (virDomainDiskIndexByName): Also allow
searching by path, and decide whether ambiguity is okay.
(virDomainDiskPathByName): New function.
(virDomainDiskRemoveByName, virDomainSnapshotAlignDisks): Update
callers.
* src/qemu/qemu_driver.c (qemudDomainBlockPeek)
(qemuDomainAttachDeviceConfig, qemuDomainUpdateDeviceConfig)
(qemuDomainGetBlockInfo, qemuDiskPathToAlias): Likewise.
* src/qemu/qemu_process.c (qemuProcessFindDomainDiskByPath):
Likewise.
* src/libxl/libxl_driver.c (libxlDomainAttachDeviceDiskLive)
(libxlDomainDetachDeviceDiskLive, libxlDomainAttachDeviceConfig)
(libxlDomainUpdateDeviceConfig): Likewise.
* src/uml/uml_driver.c (umlDomainBlockPeek): Likewise.
* src/xen/xend_internal.c (xenDaemonDomainBlockPeek): Likewise.
* docs/formatsnapshot.html.in: Update documentation.
* tools/virsh.pod (domblkstat, domblkinfo): Likewise.
* docs/schemas/domaincommon.rng (diskTarget): Tighten pattern on
disk targets.
* docs/schemas/domainsnapshot.rng (disksnapshot): Update to match.
* tests/domainsnapshotxml2xmlin/disk_snapshot.xml: Update test.
Adds an optional element to <domainsnapshot>, which will be used
to give user control over external snapshot filenames on input,
and specify generated filenames on output.
For now, no driver accepts this element; that will come later.
<domainsnapshot>
...
<disks>
<disk name='vda' snapshot='no'/>
<disk name='vdb' snapshot='internal'/>
<disk name='vdc' snapshot='external'>
<driver type='qcow2'/>
<source file='/path/to/new'/>
</disk>
</disks>
<domain>
...
<devices>
<disk ...>
<driver name='qemu' type='raw'/>
<target dev='vdc'/>
<source file='/path/to/old'/>
</disk>
</devices>
</domain>
</domainsnapshot>
* src/conf/domain_conf.h (_virDomainSnapshotDiskDef): New type.
(_virDomainSnapshotDef): Add new elements.
(virDomainSnapshotAlignDisks): New prototype.
* src/conf/domain_conf.c (virDomainSnapshotDiskDefClear)
(virDomainSnapshotDiskDefParseXML, disksorter)
(virDomainSnapshotAlignDisks): New functions.
(virDomainSnapshotDefParseString): Parse new fields.
(virDomainSnapshotDefFree): Clean them up.
(virDomainSnapshotDefFormat): Output them.
* src/libvirt_private.syms (domain_conf.h): Export new function.
* docs/schemas/domainsnapshot.rng (domainsnapshot, disksnapshot):
Add more xml.
* docs/formatsnapshot.html.in: Document it.
* tests/domainsnapshotxml2xmlin/disk_snapshot.xml: New test.
* tests/domainsnapshotxml2xmlout/disk_snapshot.xml: Update.
In order to distinguish disk snapshots from system checkpoints, a
new state value that is only valid for snapshots is helpful.
* include/libvirt/libvirt.h.in (VIR_DOMAIN_LAST): New placeholder.
* src/conf/domain_conf.h (virDomainSnapshotState): New enum mapping.
(VIR_DOMAIN_DISK_SNAPSHOT): New internal enum value.
* src/conf/domain_conf.c (virDomainState): Use placeholder.
(virDomainSnapshotState): Extend mapping by one for use in snapshot.
(virDomainSnapshotDefParseString, virDomainSnapshotDefFormat):
Handle new state.
(virDomainObjSetState, virDomainStateReasonToString)
(virDomainStateReasonFromString): Avoid compiler warnings.
* tools/virsh.c (vshDomainState, vshDomainStateReasonToString):
Likewise.
* src/libvirt_private.syms (domain_conf.h): Export new functions.
* docs/schemas/domainsnapshot.rng: Tighten state definition.
* docs/formatsnapshot.html.in: Document it.
* tests/domainsnapshotxml2xmlout/disk_snapshot.xml: New test.
As discussed here:
https://www.redhat.com/archives/libvir-list/2011-August/msg00361.htmlhttps://www.redhat.com/archives/libvir-list/2011-August/msg00552.html
Adds snapshot attribute and transient sub-element:
<devices>
<disk type=... snapshot='no|internal|external'>
...
<transient/>
</disk>
</devices>
* docs/schemas/domaincommon.rng (snapshot): New define.
(disk): Add snapshot and persistent attributes.
* docs/formatdomain.html.in: Document them.
* src/conf/domain_conf.h (virDomainDiskSnapshot): New enum.
(_virDomainDiskDef): New fields.
* tests/qemuxml2argvdata/qemuxml2argv-disk-transient.xml: New
test of rng, no args counterpart until qemu support is complete.
* tests/qemuxml2argvdata/qemuxml2argv-disk-snapshot.args: New
file, snapshot attribute does not affect args.
* tests/qemuxml2argvdata/qemuxml2argv-disk-snapshot.xml: Likewise.
* tests/qemuxml2argvtest.c (mymain): Run new test.
Fix bug #611823 storage driver should prohibit pools with duplicate
underlying storage.
Add internal API virStoragePoolSourceFindDuplicate() to do uniqueness
check based on source location infomation for pool type.
* AUTHORS: add Lei Li
Commit 69278878 fixed one direction of arbitrarily-named snapshots,
but not the round trip path. While auditing domain_conf, I found
a couple other instances that weren't escaping arbitrary strings.
* src/conf/domain_conf.c (virDomainFSDefFormat)
(virDomainGraphicsListenDefFormat, virDomainSnapshotDefFormat):
Escape arbitrary strings.
Just like VM saved state images (virsh save), snapshots MUST
track the inactive domain xml to detect any ABI incompatibilities.
The indentation is not perfect, but functionality comes before form.
Later patches will actually supply a full domain; for now, this
wires up the storage to support one, but doesn't ever generate one
in dumpxml output.
Happily, libvirt.c was already rejecting use of VIR_DOMAIN_XML_SECURE
from read-only connections, even though before this patch, there was
no information to be secured by the use of that flag.
And while we're at it, mark the libvirt snapshot metadata files
as internal-use only.
* src/libvirt.c (virDomainSnapshotGetXMLDesc): Document flag.
* src/conf/domain_conf.h (_virDomainSnapshotDef): Add member.
(virDomainSnapshotDefParseString, virDomainSnapshotDefFormat):
Update signature.
* src/conf/domain_conf.c (virDomainSnapshotDefFree): Clean up.
(virDomainSnapshotDefParseString): Optionally parse domain.
(virDomainSnapshotDefFormat): Output full domain.
* src/esx/esx_driver.c (esxDomainSnapshotCreateXML)
(esxDomainSnapshotGetXMLDesc): Update callers.
* src/vbox/vbox_tmpl.c (vboxDomainSnapshotCreateXML)
(vboxDomainSnapshotGetXMLDesc): Likewise.
* src/qemu/qemu_driver.c (qemuDomainSnapshotCreateXML)
(qemuDomainSnapshotLoad, qemuDomainSnapshotGetXMLDesc)
(qemuDomainSnapshotWriteMetadata): Likewise.
* docs/formatsnapshot.html.in: Rework doc example.
Based on a patch by Philipp Hahn.
Minor semantic change - allow domain xml to be generated in place
within a larger buffer, rather than having to go through a
temporary string.
* src/conf/domain_conf.c (virDomainDefFormatInternal): Add
parameter.
(virDomainDefFormat, virDomainObjFormat): Update callers.
Redefining a qemu snapshot requires a bit of a tweak to the common
snapshot parsing code, but the end result is quite nice.
Be careful that redefinitions do not introduce circular parent
chains. Also, we don't want to allow conversion between online
and offline existing snapshots. We could probably do some more
validation for snapshots that don't already exist to make sure
they are even feasible, by parsing qemu-img output, but that
can come later.
* src/conf/domain_conf.h (virDomainSnapshotParseFlags): New
internal flags.
* src/conf/domain_conf.c (virDomainSnapshotDefParseString): Alter
signature to take internal flags.
* src/esx/esx_driver.c (esxDomainSnapshotCreateXML): Update caller.
* src/vbox/vbox_tmpl.c (vboxDomainSnapshotCreateXML): Likewise.
* src/qemu/qemu_driver.c (qemuDomainSnapshotCreateXML): Support
new public flags.
Similar to the last patch in isolating the filtering from the
client actions, so that clients don't have to reinvent the
filtering.
* src/conf/domain_conf.h (virDomainSnapshotForEachChild): New
prototype.
* src/libvirt_private.syms (domain_conf.h): Export it.
* src/conf/domain_conf.c (virDomainSnapshotActOnChild)
(virDomainSnapshotForEachChild): New functions.
(virDomainSnapshotCountChildren): Delete.
(virDomainSnapshotHasChildren): Simplify.
* src/qemu/qemu_driver.c (qemuDomainSnapshotReparentChildren)
(qemuDomainSnapshotDelete): Likewise.
This one's nasty. Ever since we fixed virHashForEach to prevent
nested hash iterations for safety reasons (commit fba550f6),
virDomainSnapshotDelete with VIR_DOMAIN_SNAPSHOT_DELETE_CHILDREN
has been broken for qemu: it deletes children, while leaving
grandchildren intact but pointing to a no-longer-present parent.
But even before then, the code would often appear to succeed to
clean up grandchildren, but risked memory corruption if you have
a large and deep hierarchy of snapshots.
For acting on just children, a single virHashForEach is sufficient.
But for acting on an entire subtree, it requires iteration; and
since we declared recursion as invalid, we have to switch to a
while loop. Doing this correctly requires quite a bit of overhaul,
so I added a new helper function to isolate the algorithm from the
actions, so that callers do not have to reinvent the iteration.
Note that this _still_ does not handle CHILDREN correctly if one
of the children is the current snapshot; that will be next.
* src/conf/domain_conf.h (_virDomainSnapshotDef): Add mark.
(virDomainSnapshotForEachDescendant): New prototype.
* src/libvirt_private.syms (domain_conf.h): Export it.
* src/conf/domain_conf.c (virDomainSnapshotMarkDescendant)
(virDomainSnapshotActOnDescendant)
(virDomainSnapshotForEachDescendant): New functions.
* src/qemu/qemu_driver.c (qemuDomainSnapshotDiscardChildren):
Replace...
(qemuDomainSnapshotDiscardDescenent): ...with callback that
doesn't nest hash traversal.
(qemuDomainSnapshotDelete): Use new function.
Each snapshot lookup was iterating over the entire hash table, O(n),
instead of honing in directly on the hash key, amortized O(1).
Besides, fixing this means that virDomainSnapshotFindByName can now
be used inside another virHashForeach iteration (without this patch,
attempts to lookup a snapshot by name during a hash iteration will
fail due to nested iteration).
* src/conf/domain_conf.c (virDomainSnapshotFindByName): Simplify.
(virDomainSnapshotObjListSearchName): Delete unused function.
So that devices can be attached to hubs. Example, to attach to first
port of a usb-hub on port 1.
<hub type='usb'>
<address type='usb' bus='0' port='1'/>
</hub>
<input type='mouse' type='usb'>
<address type='usb' bus='0' port='1.1'/>
</hub>
also add a test entry
Newer QEMU introduced cache=directsync for -drive, this patchset
is to expose it in libvirt layer.
* Introduced a new QEMU capability flag ($prefix_CACHE_DIRECTSYNC),
As even $prefix_CACHE_V2 is set, we can't known if directsync
is supported.
Audit all changes to the qemu vm->current_snapshot, and make them
update the saved xml file for both the previous and the new
snapshot, so that there is always at most one snapshot with
<active>1</active> in the xml, and that snapshot is used as the
current snapshot even across libvirtd restarts.
This patch does not fix the case of virDomainSnapshotDelete(,CHILDREN)
where one of the children is the current snapshot; that will be later.
* src/conf/domain_conf.h (_virDomainSnapshotDef): Alter member
type and name.
* src/conf/domain_conf.c (virDomainSnapshotDefParseString)
(virDomainSnapshotDefFormat): Update clients.
* docs/schemas/domainsnapshot.rng: Tighten rng.
* src/qemu/qemu_driver.c (qemuDomainSnapshotLoad): Reload current
snapshot.
(qemuDomainSnapshotCreateXML, qemuDomainRevertToSnapshot)
(qemuDomainSnapshotDiscard): Track current snapshot.
This patch moves some of the sriov related pci code from node_device driver
to src/util/pci.[ch]. Some functions had to go thru name and argument list
change to accommodate the move.
Signed-off-by: Roopa Prabhu <roprabhu@cisco.com>
Signed-off-by: Christian Benvenuti <benve@cisco.com>
Signed-off-by: David Wang <dwang2@cisco.com>
In some versions of qemu, both virtio-blk-pci and virtio-net-pci
devices can have an event_idx setting that determines some details of
event processing. When it is enabled, it "reduces the number of
interrupts and exits for the guest". qemu will automatically enable
this feature when it is available, but there may be cases where this
new feature could actually make performance worse (NB: no such case
has been found so far).
As a safety switch in case such a situation is encountered in the
field, this patch adds a new attribute "event_idx" to the <driver>
element of both disk and interface devices. event_idx can be set to
"on" (to force event_idx on in case qemu has it disabled by default)
or "off" (for force event_idx off). In the case that event_idx support
isn't present in qemu, the attribute is ignored (this on the advice of
the qemu developer).
docs/formatdomain.html.in: document the new flag (marking it as
"don't mess with this!"
docs/schemas/domain.rng: add event_idx in appropriate places
src/conf/domain_conf.[ch]: add event_idx to parser and formatter
src/libvirt_private.syms: export
virDomainVirtioEventIdx(From|To)String
src/qemu/qemu_capabilities.[ch]: detect and report event_idx in
disk/net
src/qemu/qemu_command.c: add event_idx parameter to qemu commandline
when appropriate.
tests/qemuxml2argvdata/qemuxml2argv-event_idx.args,
tests/qemuxml2argvdata/qemuxml2argv-event_idx.xml,
tests/qemuxml2argvtest.c,
tests/qemuxml2xmltest.c: test cases for event_idx.
While the first encountered dns host record is being parsed, it's
possible for virNetworkDef::hosts to point to memory that has been
allocated, but virNetworkDef::nhosts to still be 0. If there is a
failure during that time, virNetworkDef::hosts will be leaked.
Although this isn't currently the case for virNetworkDef::txtrecords,
it could become that way through future re-factoring, and it hurts
nothing to restructure the freeing of txtrecord data to match that of
hosts data.
Coverity complained that 395 out of 409 virAsprintf calls are
checked, and therefore assumed that the remaining cases are bugs
waiting to happen. But in each of these cases, a failed virAsprintf
will properly set the target string to NULL, and pass on that
failure to the caller, without wasting efforts to check the call.
Adding the ignore_value silences Coverity.
* src/conf/domain_audit.c (virDomainAuditGetRdev): Ignore
virAsprintf return value, when it behaves like we need.
* src/network/bridge_driver.c (networkDnsmasqLeaseFileNameDefault)
(networkRadvdConfigFileName, networkBridgeDummyNicName)
(networkRadvdPidfileBasename): Likewise.
* src/util/storage_file.c (absolutePathFromBaseFile): Likewise.
* src/openvz/openvz_driver.c (openvzGenerateContainerVethName):
Likewise.
* src/util/command.c (virCommandTranslateStatus): Likewise.
Originally noticed by comparing the xml generated by virDomainSave
with the xml produced by reparsing and redumping that xml, but I
also did an audit of every last use of VIR_DOMAIN_XML_INACTIVE in
domain_conf.c to ensure that no other discrepancies exist.
* src/conf/domain_conf.c (virDomainDeviceInfoIsSet): Add
parameter, and update all callers. Make static.
(virDomainNetDefFormat): Skip generated ifname.
(virDomainDefFormatInternal): Skip default <seclabel>.
(virDomainChrSourceDefParseXML): Skip generated pty path, and add
parameter. Update callers.
* src/conf/domain_conf.h (virDomainDeviceInfoIsSet): Delete.
* src/libvirt_private.syms (domain_conf.h): Update.
Using a macro ensures that all the code is looking for the same
prefix.
* src/conf/domain_conf.h (VIR_NET_GENERATED_PREFIX): New macro.
* src/conf/domain_conf.c (virDomainNetDefParseXML): Use it.
* src/uml/uml_conf.c (umlConnectTapDevice): Likewise.
* src/qemu/qemu_command.c (qemuNetworkIfaceConnect): Likewise.
Suggested by Laine Stump.
Once it's plugged in, the <listen> element will be an optional
replacement for the "listen" attribute that graphics elements already
have. If the <listen> element is type='address', it will have an
attribute called 'address' which will contain an IP address or dns
name that the guest's display server should listen on. If, however,
type='network', the <listen> element should have an attribute called
'network' that will be set to the name of a network configuration to
get the IP address from.
* docs/schemas/domain.rng: updated to allow the <listen> element
* docs/formatdomain.html.in: document the <listen> element and its
attributes.
* src/conf/domain_conf.[hc]:
1) The domain parser, formatter, and data structure are modified to
support 0 or more <listen> subelements to each <graphics>
element. The old style "legacy" listen attribute is also still
accepted, and will be stored internally just as if it were a
separate <listen> element. On output (i.e. format), the address
attribute of the first <listen> element of type 'address' will be
duplicated in the legacy "listen" attribute of the <graphic>
element.
2) The "listenAddr" attribute has been removed from the unions in
virDomainGRaphicsDef for graphics types vnc, rdp, and spice.
This attribute is now in the <listen> subelement (aka
virDomainGraphicsListenDef)
3) Helper functions were written to provide simple access
(both Get and Set) to the listen elements and their attributes.
* src/libvirt_private.syms: export the listen helper functions
* src/qemu/qemu_command.c, src/qemu/qemu_hotplug.c,
src/qemu/qemu_migration.c, src/vbox/vbox_tmpl.c,
src/vmx/vmx.c, src/xenxs/xen_sxpr.c, src/xenxs/xen_xm.c
Modify all these files to use the listen helper functions rather
than directly referencing the (now missing) listenAddr
attribute. There can be multiple <listen> elements to a single
<graphics>, but the drivers all currently only support one, so all
replacements of direct access with a helper function indicate index
"0".
* tests/* - only 3 of these are new files added explicitly to test the
new <listen> element. All the others have been modified to reflect
the fact that any legacy "listen" attributes passed in to the domain
parse will be saved in a <listen> element (i.e. one of the
virDomainGraphicsListenDefs), and during the domain format function,
both the <listen> element as well as the legacy attributes will be
output.
Every DomainNetDef has a bandwidth, as does every portgroup.
Whenever a DomainNetDef of type NETWORK is about to be used, a call is
made to networkAllocateActualDevice(). This function chooses the "best"
bandwidth object and places it in the DomainActualNetDef.
From that point on, whenever some code needs to use the bandwidth data
for the interface, it's retrieved with virDomainNetGetActualBandwidth(),
which will always return the "best" info as determined in the
previous step.
These functions parse given XML node and return pointer to the
output. Unknown elements are silently ignored. Attributes must
be integer and must fit in unsigned long long.
Free function frees elements of virBandwidth structure.
When an operation started by virDomainBlockPull completes (either with
success or with failure), raise an event to indicate the final status.
This API allow users to avoid polling on virDomainGetBlockJobInfo if
they would prefer to use an event mechanism.
* daemon/remote.c: Dispatch events to client
* include/libvirt/libvirt.h.in: Define event ID and callback signature
* src/conf/domain_event.c, src/conf/domain_event.h,
src/libvirt_private.syms: Extend API to handle the new event
* src/qemu/qemu_driver.c: Connect to the QEMU monitor event
for block_stream completion and emit a libvirt block pull event
* src/remote/remote_driver.c: Receive and dispatch events to application
* src/remote/remote_protocol.x: Wire protocol definition for the event
* src/remote_protocol-structs: structure definitions for protocol verification
* src/qemu/qemu_monitor.c, src/qemu/qemu_monitor.h,
src/qemu/qemu_monitor_json.c: Watch for BLOCK_STREAM_COMPLETED event
from QEMU monitor
The network XML is updated in the following ways:
1) The <forward> element can now contain a list of forward interfaces:
<forward .... >
<interface dev='eth10'/>
<interface dev='eth11'/>
<interface dev='eth12'/>
<interface dev='eth13'/>
</forward>
The first of these takes the place of the dev attribute that is
normally in <forward> - when defining a network you can specify
either one, and on output both will be present. If you specify
both on input, they must match.
2) In addition to forward modes of 'nat' and 'route', these new modes
are supported:
private, passthrough, vepa - when this network is referenced by a
domain's interface, it will have the same effect as if the
interface had been defined as type='direct', e.g.:
<interface type='direct'>
<source mode='${mode}' dev='${dev}>
...
</interface>
where ${mode} is one of the three new modes, and ${dev} is an interface
selected from the list given in <forward>.
bridge - if a <forward> dev (or multiple devs) is defined, and
forward mode is 'bridge' this is just like the modes 'private',
'passthrough', and 'vepa' above. If there is no forward dev
specified but a bridge name is given (e.g. "<bridge
name='br0'/>"), then guest interfaces using this network will use
libvirt's "host bridge" mode, equivalent to this:
<interface type='bridge'>
<source bridge='${bridge-name}'/>
...
</interface>
3) A network can have multiple <portgroup> elements, which may be
selected by the guest interface definition (by adding
"portgroup='${name}'" in the <source> element along with the
network name). Currently a portgroup can only contain a
virtportprofile, but the intent is that other configuration items
may be put there int the future (e.g. bandwidth config). When
building a guest's interface, if the <interface> XML itself has no
virtportprofile, and if the requested network has a portgroup with
a name matching the name given in the <interface> (or if one of the
network's portgroups is marked with the "default='yes'" attribute),
the virtportprofile from that portgroup will be used by the
interface.
4) A network can have a virtportprofile defined at the top level,
which will be used by a guest interface when connecting in one of
the 'direct' modes if the guest interface XML itself hasn't
specified any virtportprofile, and if there are also no matching
portgroups on the network.
