Commit id 'c6212539' explicitly allowed a negative value to be used for
offset and length as a shorthand for the largest value after commit id
'f18c02ec' modified virStrToLong_ui() to essentially disallow a negative
value.
However, allowing a negative value for offset ONLY worked if the negative
value was -1 since the eventual lseek() does allow a -1 to mean the end
of the file. Providing other negative values resulted in errors such as:
$ virsh vol-download --pool default qcow3-vol2 /home/vm-images/raw \
--offset -2 --length -1000
error: cannot download from volume qcow3-vol2
error: Unable to seek /home/vm-images/qcow3-vol2 to 18446744073709551614: Invalid argument
$
Thus, it seems unreasonable to expect or allow a negative value for offset
since the only benefit is to lseek() to the end of the file and then only
take advantage of how the OS would handle such a seek. For the purposes of
upload or download of volume data, that seems to be a no-op. Therefore,
disallow a negative value for offset.
Additionally, modify the man page for vol-upload and vol-download to provide
more details regarding the valid values for both offset and length.
Peter Krempa [Mon, 7 Jul 2014 14:50:11 +0000 (16:50 +0200)]
storage: Split out volume wiping as separate backend function
For non-local storage drivers we can't expect to use the "scrub" tool to
wipe the volume. Split the code into a separate backend function so that
we can add protocol specific code later.
Peter Krempa [Mon, 7 Jul 2014 13:41:33 +0000 (15:41 +0200)]
storage: wipe: Move helper code into storage backend
The next patch will move the storage volume wiping code into the
individual backends. This patch splits out the common code to wipe a
local volume into a separate backend helper so that the next patch is
simpler.
qemu: leave restricting cpuset.mems after initialization
When domain is started with numatune memory mode strict and the
nodeset does not include host NUMA node with DMA and DMA32 zones, KVM
initialization fails. This is because cgroup restrict even kernel
allocations. We are already doing numa_set_membind() which does the
same thing, only it does not restrict kernel allocations.
This patch leaves the userspace numa_set_membind() in place and moves
the cpuset.mems setting after the point where monitor comes up, but
before vcpu and emulator sub-groups are created.
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
Currently, we only bind the whole QEMU domain to memory nodes
specified in nodemask altogether. That, however, doesn't make much
sense when one wants to control from where the memory for particular
guest nodes should be allocated. QEMU allows us to do that by
specifying 'host-nodes' parameter for the 'memory-backend-ram' object,
so let's use that.
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
When qemu switched to using OptsVisitor for -numa parameter, it did
two things in the same patch. One of them is that the numa parameter
is now visible in "query-command-line-options", the second one is that
it enabled using disjoint cpu ranges for -numa specification. This
will be used in later patch.
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
numatune: Encapsulate numatune configuration in order to unify results
There were numerous places where numatune configuration (and thus
domain config as well) was changed in different ways. On some
places this even resulted in persistent domain definition not to be
stable (it would change with daemon's restart).
In order to uniformly change how numatune config is dealt with, all
the internals are now accessible directly only in numatune_conf.c and
outside this file accessors must be used.
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
Since there was already public virDomainNumatune*, I changed the
private virNumaTune to match the same, so all the uses are unified and
public API is kept:
s/vir\(Domain\)\?Numa[tT]une/virDomainNumatune/g
then shrunk long lines, and mainly functions, that were created after
that:
sed -i 's/virDomainNumatuneMemPlacementMode/virDomainNumatunePlacement/g'
And to cope with the enum name, I haad to change the constants as
well:
In XML format, by definition, order of fields should not matter, so
order of parsing the elements doesn't affect the end result. When
specifying guest NUMA cells, we depend only on the order of the 'cell'
elements. With this patch all older domain XMLs are parsed as before,
but with the 'id' attribute they are parsed and formatted according to
that field. This will be useful when we have tuning settings for
particular guest NUMA node.
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
This patch adds support for the QEMU vhost-user feature to libvirt.
vhost-user enables the communication between a QEMU virtual machine
and other userspace process using the Virtio transport protocol.
It uses a char dev (e.g. Unix socket) for the control plane,
while the data plane based on shared memory.
Eric Blake [Mon, 14 Jul 2014 16:13:18 +0000 (10:13 -0600)]
blockjob: wait for pivot to complete
https://bugzilla.redhat.com/show_bug.cgi?id=1119173 documents that
commit eaba79d was flawed in the implementation of the
VIR_DOMAIN_BLOCK_JOB_ABORT_ASYNC flag when it comes to completing
a blockcopy. Basically, the qemu pivot action is async (the QMP
command returns immediately, but the user must wait for the
BLOCK_JOB_COMPLETE event to know that all I/O related to the job
has finally been flushed), but the libvirt command was documented
as synchronous by default. As active block commit will also be
using this code, it is worth fixing now.
* src/qemu/qemu_driver.c (qemuDomainBlockJobImpl): Don't skip wait
loop after pivot.
Eric Blake [Tue, 15 Jul 2014 19:44:26 +0000 (13:44 -0600)]
util: forbid freeing const pointers
Now that we've finally fixed all the violators, it's time to
enforce that any pointer to a const object is never freed (it
is aliasing some other memory, where the non-const original
should be freed instead). Alas, the code still needs a normal
vs. Coverity version, but at least we are still guaranteeing
that the macro call evaluates its argument exactly once.
I verified that we still get the following compiler warnings,
which in turn halts the build thanks to -Werror on gcc (hmm,
gcc 4.8.3's placement of the ^ for ?: type mismatch is a bit
off, but that's not our problem):
int oops1 = 0;
VIR_FREE(oops1);
const char *oops2 = NULL;
VIR_FREE(oops2);
struct blah { int dummy; } oops3;
VIR_FREE(oops3);
util/virauthconfig.c:159:35: error: pointer/integer type mismatch in conditional expression [-Werror]
VIR_FREE(oops1);
^
util/virauthconfig.c:161:5: error: passing argument 1 of 'virFree' discards 'const' qualifier from pointer target type [-Werror]
VIR_FREE(oops2);
^
In file included from util/virauthconfig.c:28:0:
util/viralloc.h:79:6: note: expected 'void *' but argument is of type 'const void *'
void virFree(void *ptrptr) ATTRIBUTE_NONNULL(1);
^
util/virauthconfig.c:163:35: error: type mismatch in conditional expression
VIR_FREE(oops3);
^
* src/util/viralloc.h (VIR_FREE): No longer cast away const.
* src/xenapi/xenapi_utils.c (xenSessionFree): Work around bogus
header.
Chunyan Liu [Tue, 15 Jul 2014 08:49:47 +0000 (16:49 +0800)]
add nocow test case
Add file in storagevolxml2xmlin and storagevolxml2xmlout, let
storagevolxml2xmltest and storagevolschematest cover 'nocow'.
Add test case to storagevolxml2argvtest to cover 'nocow'.
Chunyan Liu [Tue, 15 Jul 2014 08:49:46 +0000 (16:49 +0800)]
storagevol: add nocow to vol xml
Add 'nocow' to storage volume xml so that user can have an option
to set NOCOW flag to the newly created volume. It's useful on btrfs
file system to enhance performance.
Btrfs has low performance when hosting VM images, even more when the guest
in those VM are also using btrfs as file system. One way to mitigate this
bad performance is to turn off COW attributes on VM files. Generally, there
are two ways to turn off COW on btrfs: a) by mounting fs with nodatacow,
then all newly created files will be NOCOW. b) per file. Add the NOCOW file
attribute. It could only be done to empty or new files.
This patch tries the second way, according to 'nocow' option, it could set
NOCOW flag per file:
for raw file images, handle 'nocow' in libvirt code; for non-raw file images,
pass 'nocow=on' option to qemu-img, and let qemu-img to handle that (requires
qemu-img version >= 2.1).
Michal Privoznik [Tue, 15 Jul 2014 11:36:00 +0000 (13:36 +0200)]
Fix const correctness
In many places we define a variable as a 'const char *' when in fact
we modify it just a few lines below. Or even free it. We should not do
that.
There's one exception though, in xenSessionFree() xenapi_utils.c. We
are freeing the xen_session structure which is defined in
xen/api/xen_common.h public header. The structure contains session_id
which is type of 'const char *' when in fact it should have been just
'char *'. So I'm leaving this unmodified, just noticing the fact in
comment.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Peter Krempa [Tue, 15 Jul 2014 12:41:58 +0000 (14:41 +0200)]
storage: fs: Don't fail volume update if backing store isn't accessible
When the backing store of a volume wasn't accessible while updating the
volume definition the call would fail altogether. In cases where we
currently (incorrectly) treat remote backing stores as local one this
might lead to strange errors.
Ignore the opening errors until we figure out how to track proper volume
metadata.
Peter Krempa [Tue, 15 Jul 2014 12:33:23 +0000 (14:33 +0200)]
storage: fs: Properly parse backing store info
Use the backing store parser to properly create the information about a
volume's backing store. Unfortunately as the storage driver isn't
prepared to allow volumes backed by networked filesystems add a
workaround that will avoid changing the XML output.
Ján Tomko [Tue, 15 Jul 2014 12:32:03 +0000 (14:32 +0200)]
Fix assignment of comparison against zero
Assign the value we're comparing:
(val = func()) < 0
instead of assigning the comparison value:
(val = func() < 0)
Both were introduced along with the code,
the TLS tests by commit bd789df in 0.9.4
net events by commit de87691 in 1.2.2.
Note that the event id type fix is a no-op:
vshNetworkEventIdTypeFromString can only return
-1 (failure) and the event is never used or
0 (the only possible event) and the value of 0 < 0 is still 0.
Rework the apparmor lxc profile abstraction to mimic ubuntu's container-default.
This profile allows quite a lot, but strives to restrict access to
dangerous resources.
Removing the explicit authorizations to bash, systemd and cron files,
forces them to keep the lxc profile for all applications inside the
container. PUx permissions where leading to running systemd (and others
tasks) unconfined.
Put the generic files, network and capabilities restrictions directly
in the TEMPLATE.lxc: this way, users can restrict them on a per
container basis.
Rename linuxDomainInterfaceStats to virNetInterfaceStats in order
to allow adding platform specific implementations without
making consumer worrying about specific implementation to be used.
Also, rename util/virstatslinux.c to util/virstats.c so placing
other platform specific implementations into this file don't
look unexpected from the file name.
Chunyan Liu [Tue, 15 Jul 2014 05:03:16 +0000 (13:03 +0800)]
libxl: fix return value error Attach|DetachDeviceFlags
Code logic in libxlDomainAttachDeviceFlags and libxlDomainDetachDeviceFlags
is wrong with return value in error cases.
'ret' was being set to 0 if 'flags & VIR_DOMAIN_DEVICE_MODIFY_CONFIG' was
false. Then if something like virDomainDeviceDefParse() failed in the
VIR_DOMAIN_DEVICE_MODIFY_LIVE logic, the error would be reported but the
function would return success.
spec: Update polkit dependencies for CVE-2013-4311
Use secured polkit on distros which provide it. However, RHEL-6 will
still allow for older polkit-0.93 rather than forcing polkit-0.96-5
which is not available in all RHEL-6 releases.
4cc1f1a01fb338de939ba88eb933931687b22336 introduced a crash when doing a
block copy as virStorageSourceInitChainElement was called on
"disk->mirror" that is still NULL at that point instead of "mirror"
which temporarily holds the mirror source struct until it's fully
initialized. This resulted into a crash as a NULL was dereferenced.
John Ferlan [Mon, 14 Jul 2014 16:17:44 +0000 (12:17 -0400)]
GetBlockInfo: Use the correct path to qemuOpenFile
Commit id '3ea661de' refactored the code to use the 'disk->src->path'
instead of getting the path from virDomainDiskGetSource(). The one
call to qemuOpenFile() didn't use the disk source path, rather it used
the path as passed from the caller (in this case 'vda') - this caused
a failure with the virt-test/tp-libvirt as follows:
$ virsh domblkinfo virt-tests-vm1 vda
error: cannot stat file '/home/virt-test/shared/data/images/jeos-20-64.qcow2': Bad file descriptor
Eric Blake [Mon, 23 Jun 2014 21:59:02 +0000 (15:59 -0600)]
docs: mention more about older capability feature bits
Our documentation for features was rather sparse; this fleshes out
more of the details for other existing capabilities (and cost me
some time trawling git history).
* docs/formatcaps.html.in: Document it feature bits.
Chunhe Li [Mon, 14 Jul 2014 10:37:50 +0000 (12:37 +0200)]
openvswitch: Delete port if it exists while adding a new one
If the openvswitch service is stopped, and is followed by destroying a
VM, the openvswitch bridge translates into a state where it doesn't
recover the port configuration. While it successfully fetches data
from the internal DB, since the corresponding virtual interface does
not exists anymore the whole recovery process fails leaving restarted
VM with inability to connect to the bridge. The following set of
commands will trigger the problem:
virsh start vm
service openvswitch-switch stop
virsh destroy vm
service openvswitch-switch start
virsh start vm
Signed-off-by: Chunhe Li <lichunhe@huawei.com> Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
We've always done that. Well, until 990e46c45. Point is, if we don't
format model, we may lose a domain on libvirtd restart. If the
seclabel is implicit however, we should skip it's formatting.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Peter Krempa [Mon, 7 Jul 2014 12:38:10 +0000 (14:38 +0200)]
doc: Be more specific about semantics of _REUSE_EXT flag
Snapshots and block-copy have a flag that forces qemu to re-use existing
file. Our docs weren't exactly clear on what the existing file should
contain for this to actually work.
Re-word the docs a bit to state that the file needs to be pre-created in
the desired format and the backing chain metadata needs to be set prior
to handing it over to qemu.
conf: Fix possible NULL dereference in virStorageVolTargetDefFormat
Commit dae1568c6c6455091e8cd9bc2e90a22af3d3880c converted the perms
member of the virStorageVolTarget struct into a pointer to make it
optional. But virStorageVolTargetDefFormat did not check perms for
NULL before dereferencing it.
Ian Campbell [Fri, 11 Jul 2014 13:43:47 +0000 (14:43 +0100)]
libxl: Correct cast to virDomainDiskDiscard enum.
This was converted to a typedef in 5a2bd4c9171d "conf: more enum
cleanups in "src/conf/domain_conf.h"" causing:
libxl/libxl_conf.c: In function 'libxlDiskSetDiscard':
libxl/libxl_conf.c:724:19: error: conversion to incomplete type
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Peter Krempa [Mon, 7 Jul 2014 14:50:11 +0000 (16:50 +0200)]
storage: Split out volume upload/download as separate backend function
For non-local storage drivers we can't expect to use the FDStream
backend for up/downloading volumes. Split the code into a separate
backend function so that we can add protocol specific code later.
Ján Tomko [Wed, 9 Jul 2014 08:57:33 +0000 (10:57 +0200)]
check for cfg->spiceTLS earlier in qemuProcessSPICEAllocatePorts
This saves a few lines of code and catches the error when:
<spice autoport ='yes' defaultMode='any' ..>
<channel name='main' mode='secure'/>
</spice>
is specified with spice_tls = 0 in qemu.conf.
Instead of this error in qemuBuildGraphicsSPICECommandLine:
error: unsupported configuration: spice secure channels set in XML
configuration, but TLS port is not provided
an error is reported in qemuProcessSPICEAllocatePorts:
error: unsupported configuration: Auto allocation of spice TLS port
requested but spice TLS is disabled in qemu.conf
When creating cgroups for vcpu and emulator threads whilst starting a
domain, we explicitly skip creating those cgroups in case priv->cgroup
is NULL (cgroups not supported) because SetAffinity() serves the same
purpose. If the host supports only some cgroups (the ones we need are
either unmounted or disabled in qemu.conf), we error out with weird
message even though we could continue starting the domain.
virsh: document the possibility of accepting integers for numatune mode
According to the code, 'virsh numatune' supports integers for
specifying --mode as well as the string definitions "strict",
"interleave", and "preferred". However, this possibility was not
documented anywhere, so this patch adds it to both the man page and
command help.
The commit referenced above changed function arguments of
virStorageFileGetMetadataFromBuf() but didn't tweak the
ATTRIBUTE_NONNULL tied to them. This was caught by coverity as it
actually obeys them. We disabled them for GCC and thus it didn't show
up.
Additionally in commit 3ea661deeabadc3c114dfb6f662b9fd17d714a01 I passed
NULL to the backingFormat argument which was also marked as nonnull. Use
a dummy int's address when the argument isn't supplied so that the code
doesn't need to change much.
Peter Krempa [Tue, 8 Jul 2014 13:52:32 +0000 (15:52 +0200)]
conf: Improve metadata type verification
Split out checking of invalid metadata type from the switch statement so
that we can use the typecasted enum value to allow tracking addition of
new items by the compliler.
Jincheng Miao [Fri, 27 Jun 2014 14:37:02 +0000 (22:37 +0800)]
qemu: fix domxml-to-native failing when spice_tls is not enabled
The default graphics channel mode is 'any', so as to defaultMode attribute.
If defaultMode and channel mode are all the default value 'any',
qemuConnectDomainXMLToNative will set TLSPort.
But in qemuBuildGraphicsSPICECommandLine, if spice_tls is not enabled, libvirtd
will report an error to tell the user that spice TLS is disabled in qemu.conf.
So qemuConnectDomainXMLToNative should check spice_tls is enabled,
then decide to allocate an tlsPort number to this graphics.
If user specified defaultMode is 'secure', qemuConnectDomainXMLToNative
could allocate tlsPort, and then let qemuBuildGraphicsSPICECommandLine reports
the spice_tls disabled error.
The related bug is:
https://bugzilla.redhat.com/show_bug.cgi?id=1113868
Signed-off-by: Jincheng Miao <jmiao@redhat.com> Signed-off-by: Ján Tomko <jtomko@redhat.com>
Peter Krempa [Mon, 30 Jun 2014 12:21:23 +0000 (14:21 +0200)]
qemu: snapshot: Refactor image labelling of new snapshot files
Now that cgroups/security driver/locking driver support labelling of
individual images and tolerate network storage we don't have to refrain
from passing all image files to it. This allows removing the checking
code as we already make sure that the snapshot function won't be called
with unsupported options.
Peter Krempa [Wed, 25 Jun 2014 15:23:44 +0000 (17:23 +0200)]
qemu: Refactor qemuDomainPrepareDiskChainElement
Now that security, cgroup and locking APIs support working on individual
images and we track the backing chain security info on a per-image basis
we can finally kill swapping the disk source in virDomainDiskDef and use
the virStorageSource directly.
Peter Krempa [Thu, 12 Jun 2014 14:57:43 +0000 (16:57 +0200)]
qemu: snapshot: Improve approach to deal with snapshot metadata
Until now we were changing information about the disk source via
multiple steps of copying data. Now that we changed to a pointer to
store the disk source we might use it to change the approach to track
the data.
Additionally this will allow proper tracking of the backing chain.
Peter Krempa [Fri, 27 Jun 2014 14:12:20 +0000 (16:12 +0200)]
qemu: block: Properly track disk source while pivoting to new image
When pivoting to a new disk source after a block commit (and possibly
after a soon-to-be-added active block commit) we changed just a few
fields to the new target. In case we'd copy a network disk to a local
file we'd not change the type properly.
To avoid such problems, switch to tracking of the source via changing of
the complete source struct to the one tracking the mirroring info.
Peter Krempa [Wed, 25 Jun 2014 15:15:17 +0000 (17:15 +0200)]
qemu: blockcopy: Use the mirror disk source to label the files
Use the source struct and the corresponding function so that we can
avoid using the path separately. Now that
qemuDomainPrepareDiskChainElementPath isn't use anywhere, we can safely
remove it.
Additionally, the removal fixes a misaligned comment as the removed
function was added under a comment for a different function.
Peter Krempa [Mon, 23 Jun 2014 14:35:34 +0000 (16:35 +0200)]
security: Introduce APIs to label single images
Add security driver functions to label separate storage images using the
virStorageSource definition. This will help to avoid the need to do ugly
changes to the disk struct and use the source directly.
Peter Krempa [Wed, 18 Jun 2014 11:09:05 +0000 (13:09 +0200)]
qemu: cgroup: Add functions to set cgroup image stuff on individual imgs
Add functions that will allow to set all the required cgroup stuff on
individual images taking a virStorageSourcePtr. Also convert functions
designed to setup whole backing chain to take advantage of the change.
When dispatching events from the event loop, the array of registered
handles is searched to see what handles happened an event on. However,
the array is searched in weird way: the check for the array boundaries
is at the end, so we may touch the elements after the end of the
array:
==10434== Invalid read of size 4
==10434== at 0x52D06B6: virEventPollDispatchHandles (vireventpoll.c:486)
==10434== by 0x52D10E4: virEventPollRunOnce (vireventpoll.c:660)
==10434== by 0x52CF207: virEventRunDefaultImpl (virevent.c:308)
==10434== by 0x1639D1: virNetServerRun (virnetserver.c:1139)
==10434== by 0x1220DC: main (libvirtd.c:1507)
==10434== Address 0xc11ff04 is 4 bytes after a block of size 960 alloc'd
==10434== at 0x4C2CA5E: realloc (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==10434== by 0x52AD378: virReallocN (viralloc.c:245)
==10434== by 0x52AD46E: virExpandN (viralloc.c:294)
==10434== by 0x52AD5B1: virResizeN (viralloc.c:352)
==10434== by 0x52CF2EC: virEventPollAddHandle (vireventpoll.c:116)
==10434== by 0x52CEF5B: virEventAddHandle (virevent.c:78)
==10434== by 0x11F69A90: nodeStateInitialize (node_device_udev.c:1797)
==10434== by 0x53C3C89: virStateInitialize (libvirt.c:743)
==10434== by 0x120563: daemonRunStateInit (libvirtd.c:919)
==10434== by 0x5317719: virThreadHelper (virthread.c:197)
==10434== by 0x8376F39: start_thread (in /lib64/libpthread-2.17.so)
==10434== by 0x8A7F9FC: clone (in /lib64/libc-2.17.so)
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Peter Krempa [Tue, 8 Jul 2014 15:34:56 +0000 (17:34 +0200)]
util: cgroup: Fix build on non-cgroup platforms
Commit a48f44510098cead629ede9a49ea4e840a28ccca introduced a helper
function to convert cgroup device mode to string. The function was only
conditionally compiled on platforms that support cgroup. This broke the
build when attempting to export the symbol:
CCLD libvirt.la
Cannot export virCgroupGetDevicePermsString: symbol not defined
Move the function out of the ifdef, as it doesn't really depend on the
cgroup code being present.
Jim Fehlig [Tue, 8 Jul 2014 21:34:48 +0000 (15:34 -0600)]
libxl: fix crash in migrate confirm for transient domains
In libxlDomainMigrationConfirm(), a transient domain is removed
from the domain list after successful migration. Later in cleanup,
the domain object is unlocked, resulting in a crash
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7fb4208ed700 (LWP 12044)]
0x00007fb4267251e6 in virClassIsDerivedFrom (klass=0xdeadbeef,
parent=0x7fb42830d0c0) at util/virobject.c:169
169 if (klass->magic == parent->magic)
(gdb) bt
0 0x00007fb4267251e6 in virClassIsDerivedFrom (klass=0xdeadbeef,
parent=0x7fb42830d0c0) at util/virobject.c:169
1 0x00007fb42672591b in virObjectIsClass (anyobj=0x7fb4100082b0,
klass=0x7fb42830d0c0) at util/virobject.c:365
2 0x00007fb42672583c in virObjectUnlock (anyobj=0x7fb4100082b0)
at util/virobject.c:338
3 0x00007fb41a8c7d7a in libxlDomainMigrationConfirm (driver=0x7fb4100404c0,
vm=0x7fb4100082b0, flags=1, cancelled=0) at libxl/libxl_migration.c:583
Fix by setting the virDomainObjPtr to NULL after removing it from
the domain list.
Jim Fehlig [Tue, 8 Jul 2014 21:17:58 +0000 (15:17 -0600)]
libxl: acquire job though begin phase only
During migration, the libxl driver starts a modify job in the
begin phase, ending the job in the confirm phase. This is
essentially VIR_MIGRATE_CHANGE_PROTECTION semantics, but the
driver does not support that flag. Without CHANGE_PROTECTION
support, the job would never be terminated in error conditions
where migrate confirm phase is not executed. Further attempts
to modify the domain would result in failure to acquire a job
after LIBXL_JOB_WAIT_TIME.
Similar to the qemu driver, end the job in the begin phase.
Protecting the domain object across all phases of migration can
be done in a future patch adding CHANGE_PROTECTION support.