Commit Graph

34134 Commits

Author SHA1 Message Date
Michal Privoznik
9b332820f3 lib: Format PCI address differently
Currently, the way we format PCI address is using printf-s
precision, e.g. "%.4x". This works if we don't want to print any
value outside of bounds (which is usually the case). However,
turns out, PCI domain can be 0x10000 which doesn't work well with
our format strings. However, if we change the format string to
"%04x" then we still pad small values with zeroes but also we are
able to print values that are larger than four digits. In fact,
this format string used by kernel to print a PCI address:

  "%04x:%02x:%02x.%d"

The other three format strings (for bus, device and function) are
changed too, so that we use the same format string as kernel.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-08-05 19:42:15 +02:00
Michal Privoznik
f0c50bc1ce lib: Unify PCI address formatting
The format string for a PCI address is copied over and over
again, often with slight adjustments. Introduce global
VIR_PCI_DEVICE_ADDRESS_FMT macro that holds the formatting string
and use it wherever possible.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-08-05 19:42:15 +02:00
Michal Privoznik
a0a341e82a virPCIDevice: Make @name dynamically allocated
In near future, the length restriction of PCI domain is going to
be lifted. This means that our assumption that PCI address is 13
bytes long is no longer true. We can avoid this problem by making
@name dynamically allocated and thus not bother with actual
length of stringified PCI address.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-08-05 19:42:15 +02:00
Michal Privoznik
1ab3d8b49e virPCIDeviceNew: Prefer VIR_RETURN_PTR
This function declares @ret variable and then uses
VIR_STEAL_PTR() to avoid freeing temporary variable @dev which is
constructed. Well, as of 267f1e6da5 we have VIR_RETURN_PTR()
macro so that we can avoid this pattern.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-08-05 19:42:15 +02:00
Michal Privoznik
1737d11e1b qemuBuildPCIHostdevDevStr: Always format PCI domain onto cmd line
While it's true that older QEMUs were not able to deal with PCI
domains, we don't support those versions anymore (see
4a42ece13a). Therefore it is safe to always format fully
expanded PCI address. Format PCI domain always as it will
simplify next commits.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-08-05 19:42:15 +02:00
Wang Huaqiang
86e3de0565 conf: Refactor and rename the function to validate a new resctrl monitor
A new algorithm for detecting the vcpus and monitor type conflicts
between new monitor an existing allocation and monitor groups.

After refactoring, since we are verifying both @vcpus and monitor
type @tag at the same time, the validating function name has been
renamed from virDomainResctrlMonValidateVcpus to
virDomainResctrlValidateMonitor.

Signed-off-by: Wang Huaqiang <huaqiang.wang@intel.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2019-08-05 19:41:12 +02:00
Wang Huaqiang
59ad6fd4f8 util: Remove unused virResctrlMonitorGetCacheOccupancy
Signed-off-by: Wang Huaqiang <huaqiang.wang@intel.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2019-08-05 19:41:12 +02:00
Wang Huaqiang
9549a8967a util: Extend virresctl API to retrieve multiple monitor statistics
Export virResctrlMonitorGetStats and make
virResctrlMonitorGetCacheOccupancy obsoleted.

Signed-off-by: Wang Huaqiang <huaqiang.wang@intel.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2019-08-05 19:41:12 +02:00
Wang Huaqiang
c09a14e5b4 util: Refactor 'virResctrlMonitorStats'
Refactor 'virResctrlMonitorStats' to track multiple statistical
records.

Signed-off-by: Wang Huaqiang <huaqiang.wang@intel.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2019-08-05 19:41:12 +02:00
Wang Huaqiang
782dd229ac util: Refactor and rename 'virResctrlMonitorFreeStats'
Refactor and rename 'virResctrlMonitorFreeStats' to
'virResctrlMonitorStatsFree' to free one
'virResctrlMonitorStatsPtr' object.

Signed-off-by: Wang Huaqiang <huaqiang.wang@intel.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2019-08-05 19:41:12 +02:00
Wang Huaqiang
6d7d79856c conf: Append 'resctrl' object according to number of monitor group directly
'virResctrlAllocIsEmpty' checks if cache allocation or memory
bandwidth allocation settings are specified in configuration
file. It is not proper to be used in checking memory bandwidth
allocation is specified in XML settings because this function
could not distinguish memory bandwidth allocations from cache
allocations.

Here using the local variable @n, which indicates the cache
allocation groups or memory bandwidth groups depending on the
context it is in, to decide if append a new @resctrl object.

If @n is zero and no monitors groups specified in XML, then
we should not append a new @resctrl object to @def->resctrls.

This kind of replacement is also more efficient and avoiding
a long function calling path.

Signed-off-by: Wang Huaqiang <huaqiang.wang@intel.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2019-08-05 19:41:12 +02:00
Wang Huaqiang
df471f4188 conf: refactor 'virDomainResctrlVcpuMatch' and some code cleanup
Let 'virDomainResctrlVcpuMatch' to retrieve a pointer of
virDomainResctrlDefPtr in its third parameter instead
of virResctrlAllocPtr, if @vcpus is matched with the vcpus
of some resctrl allocation in list of @def->resctrls.

Signed-off-by: Wang Huaqiang <huaqiang.wang@intel.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2019-08-05 19:41:12 +02:00
Wang Huaqiang
4f380977fe conf: some code cleanup
Creating object and judging if it is successfully created in fewer
lines.

Signed-off-by: Wang Huaqiang <huaqiang.wang@intel.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2019-08-05 19:41:12 +02:00
Wang Huaqiang
48e188d2a8 conf: code cleanup for return error code directly
code cleanup for 'virDomainCachetuneDefParse' and
'virDomainMemorytuneDefParse'.

Signed-off-by: Wang Huaqiang <huaqiang.wang@intel.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2019-08-05 19:41:12 +02:00
Wang Huaqiang
53c87fb920 conf: code cleanup, remove empty line and one space
Remove some redundant space and line.

Signed-off-by: Wang Huaqiang <huaqiang.wang@intel.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2019-08-05 19:41:11 +02:00
Wang Huaqiang
816cef0783 util, conf: Handle default monitor group of an allocation properly
'default monitor of an allocation' is defined as the resctrl
monitor group that created along with an resctrl allocation,
which is created by resctrl file system. If the monitor group
specified in domain configuration file is happened to be a
default monitor group of an allocation, then it is not necessary
to create monitor group since it is already created. But if
an monitor group is not an allocation default group, you
should create the group under folder
'/sys/fs/resctrl/mon_groups' and fill the vcpu PIDs to 'tasks'
file.

Signed-off-by: Wang Huaqiang <huaqiang.wang@intel.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2019-08-05 19:41:11 +02:00
Michal Privoznik
0f68e1c9ba libxl: Implement domain metadata getter/setter
Fortunately, the code that handles metadata getting or setting is
driver agnostic, so all that is needed from individual hypervisor
drivers is to call the right functions.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1732306

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>
2019-08-05 19:40:14 +02:00
Roman Bolshakov
9fbf56855d tools: console: Use proper constructor
"virsh console" on macOS cannot attach to a domain and it doesn't matter if
it's local or remote domain:
  $ ~ virsh console vm
  Connected to domain vm
  Escape character is ^]
  error: internal error: unable to wait on console condition

The error comes from pthread_cond_wait that fails with EINVAL. The mutex
in the parent is not initialized with pthread_mutex_init and it results
in silent failure of pthead_mutex_lock and the attach failure.

Fixes: 98361cc3b9 ("tools: console: make console virLockableObject")
Signed-off-by: Roman Bolshakov <r.bolshakov@yadro.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2019-08-05 19:39:44 +02:00
Michal Privoznik
9f02064277 news.xml: Restore blank news example
In v5.6.0-rc1~347 I've mistakenly messed up news.xml as the
change I wanted to promote was added into a comment (I blame git
rebase for that). Anyway, restore the original state of the
comment so it can be copied again.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
2019-08-05 19:33:25 +02:00
Michal Privoznik
61819282a0 maint: Post-release version bump to 5.7.0
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
2019-08-05 19:23:46 +02:00
Daniel Veillard
bafb3d1fbe Release of libvirt-5.6.0
* docs/news.xml: updated for release

Signed-off-by: Daniel Veillard <veillard@redhat.com>
2019-08-05 19:17:01 +02:00
Andrea Bolognani
7ce621ef93 news: Update for 5.6.0 release
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Acked-by: Daniel Veillard <veillard@redhat.com>
2019-08-03 12:25:04 +02:00
Eric Blake
8bfb1371d9 tests: Fix virsh-snapshot/checkpoint without readline-devel
readline-devel is an optional build dependency; when it is not
present, the output of 'virsh <<EOF ... EOF' is different in that the
input provided by the user is not echoed, and prompts become
interleaved on the same line as actual output, which in turn causes
the sed doing prompt filtering to mess up:

| ./virsh-snapshot
| --- exp	2019-07-31 18:42:31.107399428 -0300
| +++ out.cooked	2019-07-31 18:42:31.108399437 -0300
| @@ -1,8 +1,3 @@
| -
| -
| -Domain snapshot s3 created from 's3.xml'
| -Domain snapshot s2 created from 's2.xml'
| -Name:           s2
|  Domain:         test
|  Current:        yes
|  State:          running

Maybe we should fix virsh in interactive mode to echo regardless of
whether readline-devel was used, but the quicker fix is to make the
test use 'virsh "..."' rather than reading its input from stdin.

Reported-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Tested-by: Daniel Henrique Barboza <danielhb413@gmail.com>
2019-08-02 09:44:41 -05:00
Jim Fehlig
bd24bab96a news: add entry for new max_threads_per_process option in qemu.conf
Signed-off-by: Jim Fehlig <jfehlig@suse.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
2019-08-01 09:01:22 -06:00
Eric Blake
b4ab33b90b news: Add news entry for checkpoints
Checkpoints are definitely a news-worthy addition, even if the
virDomainBackup API is not going to make it until a later release.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
2019-07-31 08:10:22 -05:00
Eric Blake
f682d88c41 news: Grammar tweaks
Wording improvements in the recent patches.

Signed-off-by: Eric Blake <eblake@redhat.com>
2019-07-31 08:09:57 -05:00
Han Han
b8114dde86 news: Support encrypted soft TPM
Signed-off-by: Han Han <hhan@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
2019-07-31 15:07:13 +02:00
Han Han
18eb0843d9 news: Allow XML validation for snapshot creation
Signed-off-by: Han Han <hhan@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
2019-07-31 15:02:34 +02:00
Andrea Bolognani
8fe64e9712 gitdm: Add some more companies
Employees from these companies have made contributions to
libvirt over the past few releases.

Signed-off-by: Andrea Bolognani <abologna@redhat.com>
2019-07-31 11:46:31 +02:00
Eric Blake
b0ecc0a04c backup: remote: Trivial whitespace fix
I messed up formatting during conflict resolution across rebasing
while preparing my checkpoint patches :)

Signed-off-by: Eric Blake <eblake@redhat.com>
2019-07-30 16:46:55 -05:00
Jiri Denemark
ad9d5d3a6a cpu: Drop CPUID definition for hv-spinlocks
hv-spinlocks is not a CPUID feature and should not be checked as such.
While starting a domain with hv-spinlocks enabled, we would report a
warning about unsupported hyperv spinlocks feature even though it was
set properly.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-07-30 17:09:53 +02:00
Daniel P. Berrangé
3bdca9273c po: refresh translations from zanata
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-07-30 12:43:31 +01:00
Vitaly Kuznetsov
37ce8cfaa3 docs: formatdomain: move 'msrs' out of Hyper-V Enlightenments
Introduced by: commit e9528f41c6

'msrs' is a feature unrelated to Hyper-V Enlightenments, the commit message
which added it and the test have it right:

    <features>
      ...
      <msrs unknown='ignore'>
      ...
    </features>

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Ján Tomko <jtomko@redhat.com>
2019-07-30 12:44:58 +02:00
Vitaly Kuznetsov
08dec3b086 docs: formatdomain: fix 'SynIC' spelling
SynIC stands for 'Synthetic Interrupt Controller', it is not a NIC. Fix the
spelling in accordance with Hypervisor Top Level Functional Specification.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Ján Tomko <jtomko@redhat.com>
2019-07-30 12:44:58 +02:00
Vitaly Kuznetsov
db9829d795 docs: formatdomain: add stimer flag to the example xml
The example XML we have contains all other Hyper-V Enlightenments but
'stimer' is missing.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Ján Tomko <jtomko@redhat.com>
2019-07-30 12:44:58 +02:00
Eric Blake
fed58d83c6 build: Fix checkpoint_conf on mingw
CI flagged a failing mingw build, due to:
In file included from ../../src/conf/checkpoint_conf.c:24:
../gnulib/lib/configmake.h:8:17: error: expected identifier or '(' before string constant
    8 | #define DATADIR "/usr/i686-w64-mingw32/sys-root/mingw/share"
      |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

As previously learned in commits bd205a90 and 976abdf6, gnulib's
configmake.h header does #define DATADIR "string...", while mingw's
<winsock2.h> expects to declare a type named DATADIR. As long as the
mingw system header is included first before configmake.h, the two
uses do not conflict, but until gnulib is patched to make configmake.h
automatically work around the issue, our immediate fix is the
workaround of rearranging our include order to insure no conflict.
Copy the paradigm used in domain_conf.c of using <unistd.h> to trigger
the indirect inclusion of <winsock2.h> on mingw.

Fixes: 1a4df34a
Signed-off-by: Eric Blake <eblake@redhat.com>
2019-07-29 13:06:39 -05:00
Andrea Bolognani
a1be4aaa96 util: Fix comment for virGetEnvAllowSUID()
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
2019-07-29 19:18:28 +02:00
Daniel P. Berrangé
532c04e297 libvirt: correctly print out URI returned from probing
Turning a NULL URI instead the empty string is very misleading when
reading the debug logs as the distinction between the two is
functionally important.

Reviewed-by: Andrea Bolognani <abologna@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-07-29 17:27:59 +01:00
Michal Privoznik
019911339b commandtest: Remove commandhelper.log in test27
The recently added test27 spawns commandhelper. This is fine,
except, one of the things that commandhelper does is it records
arguments it was spawn with into commandhelper.log. Other test
cases then use checkoutput() to compare the arguments against the
expected ones and also unlink() the log file. However, test27()
is not doing that and thus it leaves the file behind. This
breaks distcheck.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2019-07-29 16:27:05 +02:00
Ilias Stamatis
adf50b57bd test_driver: implement virDomainGetCPUStats
Signed-off-by: Ilias Stamatis <stamatis.iliass@gmail.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>
2019-07-29 15:56:46 +02:00
Ilias Stamatis
ff94f44418 tests: virsh-optparse: Drop obsolete cpu-stats test cases
These test cases will start failing once the test driver provides
implementation for the virDomainGetCPUStats API.

Signed-off-by: Ilias Stamatis <stamatis.iliass@gmail.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>
2019-07-29 15:56:46 +02:00
Michal Privoznik
642c231268 qemumonitorjsontest: Don't leak 'query-jobs' info
The returned array of qemuMonitorJobInfo structs must be freed.

164 (16 direct, 148 indirect) bytes in 1 blocks are definitely lost in loss record 64 of 84
   at 0x4A3568B: realloc (vg_replace_malloc.c:826)
   by 0x4D888BD: virReallocN (viralloc.c:244)
   by 0x4D889B3: virExpandN (viralloc.c:293)
   by 0x4D88C87: virInsertElementsN (viralloc.c:435)
   by 0x214004: qemuMonitorJSONGetJobInfo (qemu_monitor_json.c:9185)
   by 0x148B3F: testQueryJobs (qemumonitorjsontest.c:2979)
   by 0x14C192: virTestRun (testutils.c:174)
   by 0x14BF36: mymain (qemumonitorjsontest.c:3286)
   by 0x14E256: virTestMain (testutils.c:1096)
   by 0x14BFD9: main (qemumonitorjsontest.c:3298)

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
ACKed-by: Peter Krempa <pkrempa@redhat.com>
2019-07-29 15:49:19 +02:00
Jiri Denemark
4c62ed6068 qemu: Fix KVM features with QEMU 4.1
Originally the names of the KVM CPU features were only used internally
for looking up their CPUID bits. So we used "__kvm_" prefix for them to
make sure the names do not collide with normal CPU features stored in
our CPU map.

But with QEMU 4.1 we check which features were enabled or disabled by a
freshly started QEMU process using their names rather than their CPUID
bits (mostly because of MSR features). Thus we need to change our made
up internal names into the actual names used by QEMU.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Tested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-07-29 15:41:51 +02:00
Jiri Denemark
9e6172937f cpu: Drop unused KVM features
Most of the internally defined KVM CPUID features are not actually used
by libvirt. The QEMU driver may enable or disable them on the command
line, but we don't check for the associated CPU properties or CPUID
bits. They would be useless with QEMU 4.1 anyway since their names were
only remotely similar to the actual feature names.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Tested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-07-29 15:41:50 +02:00
Jiri Denemark
1ddf014fef cpu: Drop KVM_ from hyperv feature macros
All the features are hyperv features even though they are provided by
KVM with QEMU. The "KVM" part in the macro names does not make a lot of
sense.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Tested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-07-29 15:41:50 +02:00
Jiri Denemark
d99e8f01c7 qemu: Prefer dashes for hyperv features
Starting with QEMU 4.1, we're using the canonical feature names on the
command line and avoid aliases to prepare for possible deprecation of
all aliases in QEMU. But we do so only for features from our CPU map,
hyperv features defined in the code were unchanged and this patch fixes
it. Some features use "hv-" prefix unconditionally because they were
introduced recently enough to always support spelling with a dash.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Tested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-07-29 15:41:50 +02:00
Jiri Denemark
0ccdd476bb qemu: Fix hyperv features with QEMU 4.1
Originally the names of the hyperv CPU features were only used
internally for looking up their CPUID bits. So we used "__kvm_hv_"
prefix for them to make sure the names do not collide with normal CPU
features stored in our CPU map.

But with QEMU 4.1 we check which features were enabled or disabled by a
freshly started QEMU process using their names rather than their CPUID
bits (mostly because of MSR features). Thus we need to change our made
up internal names into the actual names used by QEMU. Most of the names
are only used with QEMU 4.1 and newer and the reset was introduced with
QEMU recently enough to already support spelling with "-". Thus we don't
need to define them as "hv_*" with a translation to "hv-*" for new QEMU.

Without this patch libvirt would mistakenly report all hyperv features
as unavailable and refuse to start any domain using them with QEMU 4.1.

Reported-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Tested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-07-29 15:41:50 +02:00
Eric Blake
7efe930ec3 backup: Prevent snapshots and checkpoints at same time
Earlier patches mentioned that the initial implementation will prevent
snapshots and checkpoints from being used on the same domain at once.
However, the actual restriction is done in this separate patch to make
it easier to lift that restriction via a revert, when we are finally
ready to tackle that integration in the future.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2019-07-29 08:22:29 -05:00
Eric Blake
3a204b036f backup: Wire up qemu checkpoint commands over QMP
Time to actually issue the QMP transactions that create and delete
persistent checkpoints, resolving TODOs intentionally left earlier in
the series.  For create, we only need one transaction: inside, we
visit all disks affected by the checkpoint, and create a new enabled
bitmap, as well as disabling the bitmap of the first ancestor
checkpoint (if any) that also had a bitmap.  For deletion, we need
multiple QMP calls: for each disk, if there is an ancestor checkpoint
with a bitmap, then the bitmap must be merged (including activating
the ancestor bitmap if the leaf node changes), all before deleting the
bitmap from the checkpoint being removed.

Signed-off-by: Eric Blake <eblake@redhat.com>
2019-07-29 08:15:31 -05:00
Eric Blake
e3a4b8f461 backup: qemu: Add helper API for looking up node name
Qemu bitmap operations require knowing the node name associated with
the format layer (the qcow2 file); as upcoming patches will be
grabbing that information frequently, make a helper function to access
it.

Another potential benefit of this function is that we have a single
place where we could insert a QMP node-name scraping call if we don't
currently know the node name, when -blockdev is not supported;
however, the goal is that we hopefully don't ever have to do that
because we instead scrape node names only at the point where they
change.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2019-07-29 08:15:11 -05:00