The virDomainDefineXML method is one of the few that still lacks
an 'unsigned int flags' parameter. This will be needed for adding
XML validation to this API. virDomainCreateXML fortunately already
has flags.
The members of struct virSecurityLabel and struct virSecurityModel
were not shown in the libvirt API docs because the corresponding
<field> elements were missing from the libvirt-api.xml.
The reason is that apibuild.py does not cope well with typedef's
using inline struct definitions. It fails to associate the comment
with the typedef and because of this refuses to write out the
field of the struct.
This patch introduces access to allocation information about
a backing chain of a live domain. While querying storage
volumes for read-only disks could provide some of the details,
we do NOT want to read() a file while qemu is writing it.
Also, there is one case where we have to rely on qemu: when
doing a block commit into a backing file, where that file is
stored in qcow2 format on a host block device, we want to know
the current highest write offset into that image, in order to
know if the disk must be resized larger. qemu-img does not
(currently) show this information, and none of the earlier
block APIs were extensible enough to expose it. But
virDomainListGetStats is perfect for the job!
We don't need a new group of statistics, as the existing block
group is sufficient. On the other hand, as existing libvirt
releases already report 1:1 mapping of block.count to <disk>
devices, changing the array size could confuse older clients;
and even with newer clients, the time and memory taken to
report additional statistics is not always necessary (backing
files are generally read-only except for block-commit, so while
read statistics may change, sizing statistics will not). So
the choice here is to add a new flag that only newer callers
will pass, when they are prepared for the additional information.
This patch introduces the new API, but it will take more
patches to get it implemented for qemu.
* include/libvirt/libvirt-domain.h
(VIR_CONNECT_GET_ALL_DOMAINS_STATS_BACKING): New flag.
* src/libvirt-domain.c (virConnectGetAllDomainStats): Document it,
and add a new field when it is in use.
* tools/virsh-domain-monitor.c (cmdDomstats): Use new flag.
* tools/virsh.pod (domstats): Document it.
Signed-off-by: Eric Blake <eblake@redhat.com>
The documentation for virDomainBlockInfo was confusing: it stated
that 'physical' was the size of the container, then gave an example
of it being the amount of storage used by a sparse file (that is,
for a sparse raw image on a regular file, the wording implied
capacity==physical, while allocation was smaller; but the example
instead claimed physical==allocation). Since we use 'physical' for
the last offset of a block device, we should do likewise for
regular files.
Furthermore, the example claimed that for a qcow2 regular file,
allocation==physical. At the time the code was first written,
this was true (qcow2 files were allocated sequentially, and were
never sparse, so the last sector written happened to also match
the disk space occupied); but modern qemu does much better and
can punch holes for a qcow2 with allocation < physical.
Basically, after this patch, the three fields are now reliably
mapped as:
'capacity' - how much storage the guest can see (equal to
physical for raw images, determined by image metadata otherwise)
'allocation' - how much storage the image occupies (similar to
what 'du' would report)
'physical' - the last offset of the image (similar to what 'ls'
would report)
'capacity' can be larger than 'physical' (such as for a qcow2
image that does not vary much from a backing file) or smaller
(such as for a qcow2 file with lots of internal snapshots).
Likewise, 'allocation' can be (slightly) larger than 'physical'
(such as counting the tail of cluster allocations required to
round a file size up to filesystem granularity) or smaller
(for a sparse file). A block-resize operation changes capacity
(which, for raw images, also changes physical); many non-raw
images automatically grow physical and allocation as necessary
when starting with an allocation smaller than capacity; and even
when capacity and physical stay unchanged, allocation can change
when converting sectors from holes to data or back.
Note that this does not change semantics for qcow2 images stored
on block devices; there, we still rely on qemu to report the
highest written extent for allocation. So using this API to
track when to extend a block device because a qcow2 image is
about to exceed a threshold will not see any changes.
Also, note that virStorageVolInfo is unfortunately limited to
just 'capacity' and 'allocation' (we can't expand it to add
'physical', although we can expand the XML to add it there);
historically, that struct's 'allocation' value has reported
file size for qcow2 files (what this patch terms 'physical'
for a domain block device), but disk usage for raw files (what
this patch terms 'allocation'). So follow-up patches will be
needed to make storage volumes report the same allocation
values and get at physical values, where those differ.
* include/libvirt/libvirt-domain.h (_virDomainBlockInfo): Tweak
documentation to match saner definition.
* src/qemu/qemu_driver.c (qemuDomainGetBlockInfo): For regular
files, physical size is capacity, not allocation.
Signed-off-by: Eric Blake <eblake@redhat.com>
The apibuild.py script did not handle whitespace in preprocessor
macros, so it failed to detect constants declared with '# define'
instead of '#define'. Since we now correctly indent our public
header files, we have silently lost all constants from
libvirt-api.xml. This also caused us to not detect formatting
errors in constant docs
This changes the display from:
libvirt-storage: APIs for management of storages
to
libvirt-storage: APIs for management of storage pools and volumes
In making that change I expected my build tree html output to be
regenerated; however, it wasn't because the dependency for the separated
libvirt-storage.h wasn't there. It was only present for libvirt.h.in
So I added each in the order displayed on the docs/html/index.html page
virDomainGetFSInfo returns a list of filesystems information mounted in the
guest, which contains mountpoints, device names, filesystem types, and
device aliases named by libvirt. This will be useful, for example, to
specify mountpoints to fsfreeze when taking snapshot of a part of disks.
Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama@hds.com>
As qemu is now able to notify us about change of the channel state used
for communication with the guest agent we now can more precisely track
the state of the guest agent.
To allow notifying management apps this patch implements a new event
that will be triggered on changes of the guest agent state.
Add support for bps_max and friends in the driver part.
In the part checking if a qemu is running, check if the running binary
support bps_max, if not print an error message, if yes add it to
"info" variable
Signed-off-by: Matthias Gatto <matthias.gatto@outscale.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
The cfg.mk rule for checking preprocessor indentation was
mistakenly missing the libvirt.h.in file due to bad file
extension matching rule. Fix that and the resolve the
incorrect indentation that is identified.
Create a new libvirt-host.h file to hold the public
API definitions for the virConnect type. This header
file is not self-contained, so applications will not directly
include it. They will continue to #include <libvirt/libvirt.h>
Create a new libvirt-domain.h file to hold the public
API definitions for the virDomain type. This header
file is not self-contained, so applications will not directly
include it. They will continue to #include <libvirt/libvirt.h>
Create a new libvirt-event.h file to hold the public
API definitions for the virEvent type. This header
file is not self-contained, so applications will not directly
include it. They will continue to #include <libvirt/libvirt.h>
Create a new libvirt-storage.h file to hold the public
API definitions for the virStorage/Vol type. This header
file is not self-contained, so applications will not directly
include it. They will continue to #include <libvirt/libvirt.h>
Create a new libvirt-stream.h file to hold the public
API definitions for the virStream type. This header
file is not self-contained, so applications will not directly
include it. They will continue to #include <libvirt/libvirt.h>
Note the definition of virStreamPtr is not moved, since that
must be declared early for all other libvirt APIs to be able
to reference it.
Create a new libvirt-secret.h file to hold the public
API definitions for the virSecret type. This header
file is not self-contained, so applications will not directly
include it. They will continue to #include <libvirt/libvirt.h>
Create a new libvirt-nodedev.h file to hold the public
API definitions for the virNodeDevice type. This header
file is not self-contained, so applications will not directly
include it. They will continue to #include <libvirt/libvirt.h>
Create a new libvirt-nwfilter.h file to hold the public
API definitions for the virNWFilter type. This header
file is not self-contained, so applications will not directly
include it. They will continue to #include <libvirt/libvirt.h>
Create a new libvirt-interface.h file to hold the public
API definitions for the virInterface type. This header
file is not self-contained, so applications will not directly
include it. They will continue to #include <libvirt/libvirt.h>
Create a new libvirt-network.h file to hold the public
API definitions for the virNetwork type. This header
file is not self-contained, so applications will not directly
include it. They will continue to #include <libvirt/libvirt.h>
Create a new libvirt-domain-snapshot.h file to hold the public
API definitions for the virDomainSnapshot type. This header
file is not self-contained, so applications will not directly
include it. They will continue to #include <libvirt/libvirt.h>
Aeons ago (commit 34dcbbb4, v0.8.2), we added a new libvirt event
(VIR_DOMAIN_EVENT_ID_IO_ERROR_REASON) in order to tell the user WHY
the guest halted. This is because at least VDSM wants to react
differently to ENOSPC events (resize the lvm partition to be larger,
and resume the guest as if nothing had happened) from all other events
(I/O is hosed, throw up our hands and flag things as broken). At the
time this was done, downstream RHEL qemu added a vendor extension
'__com.redhat_reason', which would be exactly one of these strings:
"enospc", "eperm", "eio", and "eother". In our stupidity, we exposed
those exact strings to clients, rather than an enum, and we also
return "" if we did not have access to a reason (which was the case
for upstream qemu).
Fast forward to now: upstream qemu commit c7c2ff0c (will be qemu 2.2)
FINALLY adds a 'nospace' boolean, after discussion with multiple
projects determined that VDSM really doesn't care about distinction
between any other error types. So this patch converts 'nospace' into
the string "enospc" for compatibility with RHEL clients that were
already used to the downstream extension, while leaving the reason
blank for all other cases (no change from the status quo).
See also https://bugzilla.redhat.com/show_bug.cgi?id=1119784
* src/qemu/qemu_monitor_json.c (qewmuMonitorJSONHandleIOError):
Parse reason field from modern qemu.
* include/libvirt/libvirt.h.in
(virConnectDomainEventIOErrorReasonCallback): Document it.
Signed-off-by: Eric Blake <eblake@redhat.com>
For the new VIR_DOMAIN_EVENT_ID_TUNABLE event we have a bunch of
constants added
VIR_DOMAIN_EVENT_CPUTUNE_<blah>
VIR_DOMAIN_EVENT_BLKDEVIOTUNE_<blah>
This naming convention is bad for two reasons
- There is no common prefix unique for the events to both
relate them, and distinguish them from other event
constants
- The values associated with the constants were chosen
to match the names used with virConnectGetAllDomainStats
so having EVENT in the constant name is not applicable in
that respect
This patch proposes renaming the constants to
VIR_DOMAIN_TUNABLE_CPU_<blah>
VIR_DOMAIN_TUNABLE_BLKDEV_<blah>
ie, given them a common VIR_DOMAIN_TUNABLE prefix.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Use the universal tunable event to report changes to user. All
blkdeviotune values are prefixed with "blkdeviotune".
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
A long time ago in a galaxy far, far away it has been decided
that libvirt will manage not only domains but host as well. And
with my latest work on qemu driver supporting huge pages, we miss
the cherry on top: an API to allocate huge pages on the run.
Currently users are forced to log into the host and adjust the
huge pages pool themselves. However, with this API the problem
is gone - they can both size up and size down the pool.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
There are now two places in libvirt which use polkit. Currently
they use pkexec, which is set to be replaced by direct DBus API
calls. Add a common API which they will both be able to use for
this purpose.
No tests are added at this time, since the impl will be gutted
in favour of a DBus API call shortly.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Now we have universal tunable event so we can use it for reporting
changes to user. The cputune values will be prefixed with "cputune" to
distinguish it from other tunable events.
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
This new event will use typedParameters to expose what has been actually
updated and the reason is that we can in the future extend any tunable
values or add new tunable values. With typedParameters we don't have to
worry about creating some other events, we will just use this universal
event to inform user about updates.
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
RDMA Live migration requires registering memory with the hardware, and
thus QEMU offers a new 'capability' to pre-register / mlock() the guest
memory in advance for higher RDMA performance before the migration
begins. This capability is disabled by default, which means QEMU will
register the memory with the hardware in an on-demand basis.
This patch exposes this capability with the following example usage:
virsh migrate --live --rdma-pin-all --migrateuri rdma://hostname domain qemu+ssh://hostname/system
Signed-off-by: Michael R. Hines <mrhines@us.ibm.com>
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
RDMA migration uses the 'setup' state in QEMU to optionally lock
all memory before the migration starts. The total time spent in
this state is exposed as VIR_DOMAIN_JOB_SETUP_TIME.
Additionally, QEMU also exports migration throughput (mbps) for both
memory and disk, so let's add them too: VIR_DOMAIN_JOB_MEMORY_BPS,
VIR_DOMAIN_JOB_DISK_BPS.
Signed-off-by: Michael R. Hines <mrhines@us.ibm.com>
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
This patch implements the VIR_DOMAIN_STATS_BLOCK group of statistics.
To do so, a helper function to get the block stats of all the disks of
a domain is added.
Signed-off-by: Francesco Romani <fromani@redhat.com>
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
This patch implements the VIR_DOMAIN_STATS_INTERFACE group of
statistics.
Signed-off-by: Francesco Romani <fromani@redhat.com>
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
This patch implements the VIR_DOMAIN_STATS_VCPU group of statistics. To
do so, this patch also extracts a helper to gather the vCPU information.
Signed-off-by: Francesco Romani <fromani@redhat.com>
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
This patch implements the VIR_DOMAIN_STATS_CPU_TOTAL group of
statistics.
Signed-off-by: Francesco Romani <fromani@redhat.com>
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
We stupidly modeled block job bandwidth after migration
bandwidth, which in turn was an 'unsigned long' and therefore
subject to 32-bit vs. 64-bit interpretations. To work around
the fact that 10-gigabit interfaces are possible but don't fit
within 32 bits, the original interface took the number scaled
as MiB/sec. But this scaling is rather coarse, and it might
be nice to tune bandwidth finer than in megabyte chunks.
Several of the block job calls that can set speed are fed
through a common interface, so it was easier to adjust them all
at once. Note that there is intentionally no flag for the new
virDomainBlockCopy; there, since the API already uses a 64-bit
type always, instead of a possible 32-bit type, and is brand
new, it was easier to just avoid scaling issues. As with the
previous patch that adjusted the query side (commit db33cc24),
omitting the new flag preserves old behavior, and the
documentation now mentions limits of what happens when a 32-bit
machine is on either client or server side.
* include/libvirt/libvirt.h.in (virDomainBlockJobSetSpeedFlags)
(virDomainBlockPullFlags)
(VIR_DOMAIN_BLOCK_REBASE_BANDWIDTH_BYTES)
(VIR_DOMAIN_BLOCK_COMMIT_BANDWIDTH_BYTES): New enums.
* src/libvirt.c (virDomainBlockJobSetSpeed, virDomainBlockPull)
(virDomainBlockRebase, virDomainBlockCommit): Document them.
* src/qemu/qemu_driver.c (qemuDomainBlockJobSetSpeed)
(qemuDomainBlockPull, qemuDomainBlockRebase)
(qemuDomainBlockCommit, qemuDomainBlockJobImpl): Support new flag.
Signed-off-by: Eric Blake <eblake@redhat.com>
When a domain is undefined, there are options to remove it's
managed save state or snapshots. However, there's another file
that libvirt creates per domain: the NVRAM variable store file.
Make sure that the file is not left behind if the domain is
undefined.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
virDomainGetJobStats gains new VIR_DOMAIN_JOB_STATS_COMPLETED flag that
can be used to fetch statistics of a completed job rather than a
currently running job.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
To date, anyone performing a block copy and pivot ends up with
the destination being treated as <disk type='file'>. While this
works for data access for a block device, it has at least one
noticeable shortcoming: virDomainGetBlockInfo() reports allocation
differently for block devices visited as files (the size of the
device) than for block devices visited as <disk type='block'>
(the maximum sector used, as reported by qemu); and this difference
is significant when trying to manage qcow2 format on block devices
that can be grown as needed.
Of course, the more powerful virDomainBlockCopy() API can already
express the ability to set the <disk> type. But a new API can't
be backported, while a new flag to an existing API can; and it is
also rather inconvenient to have to resort to the full power of
generating XML when just adding a flag to the older call will do
the trick. So this patch enhances blockcopy to let the user flag
when the resulting XML after the copy must list the device as
type='block'.
* include/libvirt/libvirt.h.in (VIR_DOMAIN_BLOCK_REBASE_COPY_DEV):
New flag.
* src/libvirt.c (virDomainBlockRebase): Document it.
* tools/virsh-domain.c (opts_block_copy, blockJobImpl): Add
--blockdev option.
* tools/virsh.pod (blockcopy): Document it.
* src/qemu/qemu_driver.c (qemuDomainBlockRebase): Allow new flag.
(qemuDomainBlockCopy): Remember the flag, and make sure it is only
used on actual block devices.
* tests/qemuxml2argvdata/qemuxml2argv-disk-mirror.xml: Test it.
Signed-off-by: Eric Blake <eblake@redhat.com>
While reviewing the new virDomainBlockCopy API, Peter Krempa
pointed out that our existing design of using MiB/s for block
job bandwidth is rather coarse, especially since qemu tracks
it in bytes/s; so virDomainBlockCopy only accepts bytes/s.
But once the new API is implemented for qemu, we will be in
the situation where it is possible to set a value that cannot
be accurately reflected back to the user, because the existing
virDomainGetBlockJobInfo defaults to the coarser units.
Fortunately, we have an escape hatch; and one that has already
served us well in the past: we can use the flags argument to
specify which scale to use (see virDomainBlockResize for prior
art). This patch fixes the query side of the API; made easier
by previous patches that split the query side out from the
modification code. Later patches will address the virsh
interface, as well retrofitting all other blockjob APIs to
also accept a flag for toggling bandwidth units.
* include/libvirt/libvirt.h.in (_virDomainBlockJobInfo)
(VIR_DOMAIN_BLOCK_COPY_BANDWIDTH): Document sizing issues.
(virDomainBlockJobInfoFlags): New enum.
* src/libvirt.c (virDomainGetBlockJobInfo): Document new flag.
* src/qemu/qemu_monitor.h (qemuMonitorBlockJobInfo): Add parameter.
* src/qemu/qemu_monitor.c (qemuMonitorBlockJobInfo): Likewise.
* src/qemu/qemu_monitor_json.h (qemuMonitorJSONBlockJobInfo):
Likewise.
* src/qemu/qemu_monitor_json.c (qemuMonitorJSONBlockJobInfo)
(qemuMonitorJSONGetBlockJobInfoOne): Likewise. Don't scale here.
* src/qemu/qemu_migration.c (qemuMigrationDriveMirror): Update
callers.
* src/qemu/qemu_driver.c (qemuDomainBlockPivot)
(qemuDomainBlockJobImpl): Likewise.
(qemuDomainGetBlockJobInfo): Likewise, and support new flag.
Signed-off-by: Eric Blake <eblake@redhat.com>
While qemu definitely caps granularity to 64 MiB, it places no
limits on buf-size. On a machine beefy enough for lots of
memory, a buf-size larger than 2 GiB is feasible, so we should
pass a 64-bit parameter.
* include/libvirt/libvirt.h.in (VIR_DOMAIN_BLOCK_COPY_BUF_SIZE):
Allow 64 bits.
Signed-off-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Let's fix this before we bake in a painful API. Since we know
that we have exactly one non-negative fd on success, we might
as well return the fd directly instead of forcing the user to
pass in a pointer. Furthermore, I found some memory and fd
leaks while reviewing the code - the idea is that on success,
libvirtd will have handed two fds in two different directions:
one to qemu, and one to the RPC client.
* include/libvirt/libvirt.h.in (virDomainOpenGraphicsFD): Drop
unneeded parameter.
* src/driver.h (virDrvDomainOpenGraphicsFD): Likewise.
* src/libvirt.c (virDomainOpenGraphicsFD): Adjust interface to
return fd directly.
* daemon/remote.c (remoteDispatchDomainOpenGraphicsFd): Adjust
semantics.
* src/qemu/qemu_driver.c (qemuDomainOpenGraphicsFD): Likewise,
and plug fd leak.
* src/remote/remote_driver.c (remoteDomainOpenGraphicsFD):
Likewise, and plug memory and fd leak.
Signed-off-by: Eric Blake <eblake@redhat.com>
This commit (finally) adds the virDomainBlockCopy API, with the
intent that it will provide more power to the existing 'virsh
blockcopy' command.
'virsh blockcopy' was first added in Apr 2012 (v0.9.12), which
corresponds to the upstream qemu 1.2 timeframe. It was done as
a hack on top of the existing virDomainBlockRebase() API call,
for two reasons: 1) it was targetting a feature that landed first
in downstream RHEL qemu, but had not stabilized in upstream qemu
at the time (and indeed, 'drive-mirror' only landed upstream in
qemu 1.3 with slight differences to the first RHEL attempt,
and later gained further parameters like granularity and buf-size
that are also worth exposing), and 2) extending an existing API
allowed it to be backported without worrying about bumping .so
versions. A virDomainBlockCopy() API was proposed at that time
[1], but we decided not to accept it into libvirt until after
upstream qemu stabilized, and it ended up getting scrapped.
Whether or not RHEL should have attempted adding a new feature
without getting it upstream first is a debate that can be held
another day; but enough time has now elapsed that we are ready to
do the interface cleanly.
[1] https://www.redhat.com/archives/libvir-list/2012-April/msg00768.html
Delaying the creation of a clean API until now has also had a
benefit: we've only recently learned of a few shortcomings in the
original design: 1) it is unable to target a network destination
(such as a gluster volume) because it hard-coded the assumption
that the destination is a local file name. Because of all the
refactoring we've done to add virStorageSourcePtr, we are in a
better position to declare an API that parses XML describing a
host storage source as the copy destination, which was not
possible had we implemented virDomainBlockCopy as it had been
originally envisioned (although a network target will have to wait
until a later libvirt release compared to the API addition to
actually be implemented). 2) the design of using MiB/sec as the
bandwidth throttle is rather coarse; qemu is actually tuned to
bytes/second, and libvirt is preventing access to that level of
detail. A later patch will add flags to existing block job API
that can request bytes/second instead of back-compat MiB/s, but as
this is a new API, we can get it right to begin with.
At least I had the foresight to create 'virsh blockcopy' as a
separate command at the UI level (commit 1f06c00) rather than
leaking the underlying API overload of virDomainBlockRebase onto
shell users.
A further note on the bandwidth option: virTypedParameters
intentionally lacks unsigned long (since variable-width
interaction between mixed 32- vs. 64-bit client/server setups is
nasty), but we have to deal with the fact that we are interacting
with existing older code that mistakenly chose unsigned long
bandwidth at a point before we decided to prohibit it in all new
API. The typed parameter is therefore unsigned long long, but
the implementation (in a later patch) will have to do overflow
detection on 32-bit platforms, as well as capping the value to
match the LLONG_MAX>>20 cap of the existing MiB/s interfaces.
* include/libvirt/libvirt.h.in (virDomainBlockCopy): New API.
(virDomainBlockJobType, virConnectDomainEventBlockJobStatus):
Update related documentation.
* src/libvirt.c (virDomainBlockCopy): Implement it.
* src/libvirt_public.syms (LIBVIRT_1.2.8): Export it.
* src/driver.h (_virDriver): New driver callback.
Signed-off-by: Eric Blake <eblake@redhat.com>
The motivation for this API is that management layers that use libvirt
usually poll for statistics using various split up APIs we currently
provide. To get all the necessary stuff, the app needs to issue a lot of
calls and aggregate the results.
The APIs I'm introducing here:
1) Returns data in a format that we can expand in the future and is
(pseudo) hierarchical. The data is returned as typed parameters where
the fields are constructed as dot-separated strings containing names and
other stuff in a list of typed params.
2) Stats for multiple (all) domains can be queried at once and are
returned in one call. This will decrease the overhead necessary to issue
multiple calls per domain multiplied by the count of domains.
3) Selectable (bit mask) fields in the returned format. This will allow
to retrieve only specific stats according to the app's need.
The stats groups will be enabled using a bit field @stats passed as the
function argument. A few sample stats groups that this API will support:
VIR_DOMAIN_STATS_STATE
VIR_DOMAIN_STATS_CPU
VIR_DOMAIN_STATS_BLOCK
VIR_DOMAIN_STATS_INTERFACE
(Note that this is only an example, the initial implementation supports
only VIR_DOMAIN_STATS_STATE while others will be added later.)
the returned typed params will use the following scheme
state.state = VIR_DOMAIN_RUNNING
state.reason = VIR_DOMAIN_RUNNING_BOOTED (the actual values according to
the enum)
cpu.count = 8
cpu.0.state = running
cpu.0.time = 1234
