Jiri Denemark [Wed, 8 Mar 2023 09:58:11 +0000 (10:58 +0100)]
docs: Document requirements on format strings in translated messages
Preserving the order of format strings (%s, ...) when translating
messages may be very hard or even impossible depending on the target
language. On the other hand, reordering them requires understanding the
C-format strings which is not something we should expect from
translators. And even if someone reorders format strings in the right
way (by addressing arguments directly using N$), someone else may use a
translation tool that requires format strings in msgid and msgstr to
match exactly and forces these correct formats to be reverted.
As a result of this, we had several reported crashes in some locales
because integers were formatted as strings. So to make such crashes less
likely to happen and to make translating our messages easier, we now
require all messages that are marked for translation to use format
strings that always refer to the same argument no matter where they
appear in a message (e.g., %1$s, %5$llu).
Signed-off-by: Jiri Denemark <jdenemar@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Peter Krempa [Thu, 30 Mar 2023 09:42:31 +0000 (11:42 +0200)]
conf: Clear pointer to freed bitmap holding hostdev's 'origstates'
'virDomainHostdevDefClear' must clear the pointers too as it can be
invoked multiple times on the same object e.g. inside
qemuDomainRemoveHostDevice once via virDomainHostdevDefFree which skips
freeing the object if it's used via <interface> and thus has a 'net'
definition corresponding to it, and then subsequently via
virDomainNetDefFree.
Fix it by clearing the pointer along with freeing it.
Fixes: d9e4075d4e9
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2182961 Signed-off-by: Peter Krempa <pkrempa@redhat.com> Reviewed-by: Ján Tomko <jtomko@redhat.com>
Andrea Bolognani [Mon, 27 Mar 2023 17:30:48 +0000 (19:30 +0200)]
qemu: Default to raw firmware for existing domains
The changes to the output files are the exact opposite of
those from commit 22207713cf8e: this is proof that the fix is
working as intended, and that existing domains will keep using
raw firmware images regardless of whether or not qcow2 images
are available on the system and have higher priority.
New domains will keep picking whatever firmware is considered
the preferred one according to the order of descriptors, as
evidenced by the fact that the recently introduced
firmware-auto-efi-abi-update-aarch64 test case is unaffected.
Signed-off-by: Andrea Bolognani <abologna@redhat.com> Reviewed-by: Martin Kletzander <mkletzan@redhat.com>
Andrea Bolognani [Mon, 27 Mar 2023 17:56:46 +0000 (19:56 +0200)]
tests: Add firmware-auto-efi-abi-update-aarch64 test case
The input is identical to that of the existing
firmware-auto-efi-aarch64 test, but in this case we want to
cover the scenario in which that input is used to define a new
domain rather than loading the definition of an existing domain
from disk.
Signed-off-by: Andrea Bolognani <abologna@redhat.com> Reviewed-by: Martin Kletzander <mkletzan@redhat.com>
Michal Privoznik [Mon, 27 Mar 2023 11:50:40 +0000 (13:50 +0200)]
tests: Compile virgdbusmock.c with GIO_COMPILATION enabled
There are couple of g_dbus_*() functions we provide an
alternative implementation for in our virgdbusmock.c. However,
these functions are declared in gio/gdbusconnection.h as:
The solution is to do what glib does when it compiles the gio
module: set GIO_COMPILATION macro which in turn annotates the
function with dllexport attribute.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com> Reviewed-by: Martin Kletzander <mkletzan@redhat.com>
There were two issues with this commit. First is the missing propagation
of CFLAGS into the build environment and second is the fact that this is
not enough to disable the check for -fsemantic-interposition. The
proper fix would require setting MESON_OPTS or similar and also add the
propagation of such variable into the cirrus builds etc., but at this
point I burned so much time on this trivial piece of rubbish that I
think it's easier to just wait for macos to gain a newer clang =D
Signed-off-by: Martin Kletzander <mkletzan@redhat.com> Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Michal Privoznik [Fri, 24 Mar 2023 11:03:28 +0000 (12:03 +0100)]
esx: Change the default username when connecting to VCenter
While it's true that the default username is:
administrator@${SSO-Domain}
in majority of cases the ${SSO-Domain} is "vsphere.local". But
our code (and what virsh displays then) says it's just
"administrator".
This is wrong also from a different POV: the username must
contain the suffix no matter what and our default suggests
otherwise.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2181234 Signed-off-by: Michal Privoznik <mprivozn@redhat.com> Reviewed-by: Martin Kletzander <mkletzan@redhat.com>
Michal Privoznik [Wed, 22 Mar 2023 15:33:32 +0000 (16:33 +0100)]
virt-host-validate: Detect SMMU support on ARMs
In vir-host-validate we do two checks related to IOMMU:
1) hardware support, and
2) kernel support.
While users are usually interested in the latter, the former also
makes sense. And for the former (hardware support) we have this
huge if-else block for nearly every architecture, except ARM.
Now, IOMMU is called SMMU in ARM world, and while there's
certainly a definitive way of detecting SMMU support (e.g. via
dumping some registers in asm), we can work around this - just
like we do for Intel and AMD - and check for an ACPI table
presence.
In ARM world, there's I/O Remapping Table (IORT) which describes
SMMU capabilities on given host and is exposed in sysfs
(regardless of arm_smmu module).
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2178885 Signed-off-by: Michal Privoznik <mprivozn@redhat.com> Reviewed-by: Ján Tomko <jtomko@redhat.com>
Michal Privoznik [Tue, 21 Mar 2023 16:01:34 +0000 (17:01 +0100)]
meson: Don't build tests when CLang lacks -fsemantic-interposition
There are some CLang versions that do not support
-fsemantic-interposition. If that's the case, the code is
optimized so much that our mocking no longer works.
Therefore, disable tests and produce a warning.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com> Reviewed-by: Martin Kletzander <mkletzan@redhat.com>
Michal Privoznik [Wed, 22 Mar 2023 11:39:21 +0000 (12:39 +0100)]
qemu_shim: Require absolute path for root directory
The virConnectOpen(), well virConnectOpenInternal() reports an
error if embed root is not an absolute path. This is a fair
requirement, but our qemu_shim doesn't check this requirement and
passes the path to mkdir(), only to fail later on, leaving the
empty directory behind:
$ ls -d asd
ls: cannot access 'asd': No such file or directory
$ virt-qemu-run -r asd whatever.xml
virt-qemu-run: cannot open qemu:///embed?root=asd: unsupported configuration: root path must be absolute
$ ls -d asd
asd
Signed-off-by: Michal Privoznik <mprivozn@redhat.com> Reviewed-by: Kristina Hanicova <khanicov@redhat.com>
Michal Privoznik [Wed, 22 Mar 2023 10:07:50 +0000 (11:07 +0100)]
qemu_domain: Drop ATTRIBUTE_NONNULL() for non-existent arguments
After cleanup done in v8.2.0-rc1~47 the
qemuDomainObjExitMonitor() and after v8.7.0-rc1~176 the
qemuDomainObjEnterMonitor() lost the @driver argument. But
corresponding ATTRIBUTE_NONNULL() annotation was not removed and
both functions are still annotated as ATTRIBUTE_NONNULL(2) even
though they accept just one argument (@obj).
Signed-off-by: Michal Privoznik <mprivozn@redhat.com> Reviewed-by: Kristina Hanicova <khanicov@redhat.com>
Andrea Bolognani [Fri, 17 Mar 2023 10:19:04 +0000 (11:19 +0100)]
qemu: Move validation check out of postparse
Suggested-by: Michal Privoznik <mprivozn@redhat.com> Signed-off-by: Andrea Bolognani <abologna@redhat.com> Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Andrea Bolognani [Fri, 17 Mar 2023 11:00:39 +0000 (12:00 +0100)]
conf: Move validation check out of postparse
The reason why it was in postparse in the first place was so
that we could could automatically enable the secure-boot feature
in some cases, but that no longer happens so we can finally move
it to the proper location.
Signed-off-by: Andrea Bolognani <abologna@redhat.com> Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Andrea Bolognani [Wed, 15 Mar 2023 19:23:58 +0000 (20:23 +0100)]
conf: Don't explicitly set the secure-boot feature
Now that we're adding information obtained from the firmware
descriptor to the domain XML, this will happen automatically
whenever a firmware that has the enrolled-keys feature ends up
being selected.
Signed-off-by: Andrea Bolognani <abologna@redhat.com> Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Andrea Bolognani [Wed, 15 Mar 2023 16:53:02 +0000 (17:53 +0100)]
qemu: Automatically add firmware type/features information
Even when the user is not taking advantage of firmware
autoselection and instead manually providing all the necessary
information, in most cases they're still going to use firmware
builds that are provided by the OS vendor, are installed in
standard paths and come with a corresponding firmware
descriptor.
Similarly, even when the user is not guiding the autoselection
process by specifying the desired status of certain features
and instead is relying on the system-level descriptor priority
being set up correctly, libvirt will still ultimately decide to
use a specific descriptor, which includes information about the
firmware's features.
In both these cases, take the additional information that were
obtained from the firmware descriptor and reflect them back into
the domain XML, where they can be conveniently inspected by the
user and management applications alike.
Signed-off-by: Andrea Bolognani <abologna@redhat.com> Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Andrea Bolognani [Tue, 14 Mar 2023 22:08:29 +0000 (23:08 +0100)]
qemu: Don't drop firmware type/features information
Now that we no longer reject configurations that include both
this information and explicit firmware details, as long of
course as everything is internally consistent, and that we've
ensured that we produce maximally compatible XML on migration,
we can stop stripping this information at the end of the
firmware selection process.
There are several advantages to keeping this information around:
* if the user wants to change the firmware configuration for
an existing VM, they can simply drop the <loader> and
<nvram> elements, tweak the firmware autoselection parameters
and let libvirt pick a firmware that matches on the new
requirements;
* management applications can inspect the XML and easily
figure out firmware-related information without having to
reverse-engineer them based on some opaque paths.
Overall, this change makes things more transparent and easier to
understand. The improvement is so significant that, in a
follow-up commit, we're going to ensure that this information is
available in even more cases.
Signed-off-by: Andrea Bolognani <abologna@redhat.com> Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Andrea Bolognani [Fri, 17 Mar 2023 10:12:31 +0000 (11:12 +0100)]
conf: Don't format firmware type/features when migrating
The combination of explicit firmware paths, which we now
produce in all cases, and firmware autoselection knobs is
explicitly rejected by libvirt 8.6.0 and newer.
Right now we produce inherently migratable XML in all cases,
since we always strip those bits, but that's going to change
soon. To prepare for that, make sure that we always skip the
problematic elements and attributes when preparing a
migratable XML.
The destination will simply receive a fully specified firmware
configuration, which is indistinguishable from one that was
manually provided by the user and is thus accepted by any old
version of libvirt, regardless of whether or not firmware
autoselection was used on the source host.
Signed-off-by: Andrea Bolognani <abologna@redhat.com> Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Andrea Bolognani [Tue, 14 Mar 2023 22:02:46 +0000 (23:02 +0100)]
conf: Remove some firmware validation checks
libvirt 8.6.0 introduced these checks and very clearly delineated
two possible firmware selection scenarios: manual firmware
selection, where the user is responsible for providing all
information, and firmware autoselection, where a list of desired
features is provided and everything else is handled by libvirt.
In the interest of maintaining the clear separation between these
two scenarios, setting most attributes when firmware autoselection
is active will result in the configuration being rejected.
This works fine, but is unnecessarily restrictive: in most cases,
the additional information that the user has provided matches
the information that libvirt would have discovered on its own by
looking at firmware descriptors, and asking the user to scrub it
from the XML only result in pointless friction.
Remove these checks entirely.
Unsurprisingly, this results in a few test cases that were
rejected until now to suddenly start working and producing
sensible results.
The firmware-auto-efi-loader-path-nonstandard test case is
notable: while we can now enable the xml2xml part of the test,
the xml2argv part is still failing, although in a slightly
different way. This is expected: since the firmware binary is a
non-standard one, libvirt is unable to figure out the missing
information from a firmware descriptor, and the configuration
is still ultimately an invalid one. However, if we were to find
such a configuration on disk at daemon startup, we would not
ignore it completely and instead would offer the user a chance
to fix it.
Signed-off-by: Andrea Bolognani <abologna@redhat.com> Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Andrea Bolognani [Thu, 16 Mar 2023 18:42:56 +0000 (19:42 +0100)]
qemu: Discard requires-smm firmware when loader.secure=no
The requires-smm feature being present in a firmware descriptor
causes loader.secure=yes to be automatically chosen for the
domain, so we have to avoid this situation or the user's choice
will be silently subverted.
Note that we can't actually encounter loader.secure=no in this
function at the moment because of earlier checks, but that's
going to change soon.
Signed-off-by: Andrea Bolognani <abologna@redhat.com> Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Andrea Bolognani [Wed, 15 Mar 2023 17:12:58 +0000 (18:12 +0100)]
qemu: Introduce qemuFirmwareMatchesPaths()
Right now we have checks in place that ensure that explicit
paths are not provided when firmware autoselection has been
enabled, but that's going to change soon.
To prepare for that, take into account user-provided paths
during firmware autoselection if present, and discard all
firmware descriptors that don't contain matching information.
Signed-off-by: Andrea Bolognani <abologna@redhat.com> Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Andrea Bolognani [Wed, 15 Mar 2023 19:51:51 +0000 (20:51 +0100)]
tests: Fix firmware descriptor masking test
Right now we're checking that firmware descriptor masking works
as intended by creating an empty file matching 60-ovmf-sb.json
in name.
However, that firmware descriptors contains the details for a
perfectly valid and quite common situation: Secure Boot being
supported by the firmware build, but being effectively disabled
by the lack of certificates in the NVRAM template.
Unmask that firmware descriptor, and instead create a dummy one
that has higher priority than all other OVMF builds and points
to paths that are obviously incorrect, which should make it
easy to notice it getting accidentally unmasked in the future.
Signed-off-by: Andrea Bolognani <abologna@redhat.com> Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
This test is intended to simulate the use of an OVMF firmware
image installed under a non-standard path. In order to make
such a configuration work, the user would have to provide
additional information.
Right now it doesn't matter, because the configuration is
rejected anyway, but the behavior is going to change slightly
in the future. Prepare by making the configuration more
complete and realistic.
Signed-off-by: Andrea Bolognani <abologna@redhat.com> Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Andrea Bolognani [Thu, 16 Mar 2023 16:36:45 +0000 (17:36 +0100)]
tests: Rename a few firmware tests
This unifies the naming between the manual and automatic
selection cases, clarifies the contents of the tests and makes
room for more tests being added in the future.
Signed-off-by: Andrea Bolognani <abologna@redhat.com> Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Michal Privoznik [Mon, 20 Mar 2023 12:38:27 +0000 (13:38 +0100)]
meson: Stop detecting -Wl,--version-script=
With its version 16.0, the LLVM's linker turned on
--no-undefined-version by default [1]. This breaks how we detect
--version-script= detection, because at the compile time there's
no library built yet that we can use to make --version-script=
happy. Unfortunately, meson does not provide a way to detect this
either [2].
But there's not much sense in detecting the argument either. We
already special case some systems (windows, darwin) and do the
check for others, which are expected to support versioned
symbols, because of ELF. Worst case scenario - the error is
reported during compile time rather than configure time.
Shaleen Bathla [Mon, 20 Mar 2023 10:39:56 +0000 (16:09 +0530)]
capabilities: reduce scope in virCapabilitiesInitCaches()
over-writing a variable in inner while-loop without freeing previous memory
leaks it over time.
To fix this, we can just change scope of bank variable to the inner loop.
Signed-off-by: Shaleen Bathla <shaleen.bathla@oracle.com> Reviewed-by: Ján Tomko <jtomko@redhat.com> Fixes: 5c84485439ee63f40002c04914e111395c598db0 Signed-off-by: Ján Tomko <jtomko@redhat.com>
Co-authored-by: Daniel P. Berrange <berrange@redhat.com> Co-authored-by: Daniel P. Berrangé <berrange@redhat.com> Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
The virNumaNodeIsAvailable function is stubbed out when building
without libnuma, such that it just returns a constant value. When
CLang is optimizing, it does inter-procedural analysis across
function calls. When it sees that the call to virNumaNodeIsAvailable
returns a fixed constant, it elides the conditional check for errors
in the callers such as virNumaNodesetIsAvailable.
This is a valid optimization as the C standard declares that there
must only be one implementation of each function in a binary. This
is normally the case, but ELF allows for function overrides when
linking or at runtime with LD_PRELOAD, which is technically outside
the mandated C language behaviour.
So while CLang's optimization works fine at runtime, it breaks in our
test suite which aims to mock the virNumaNodeIsAvailable function so
that it has specific semantics regardless of whether libnuma is built
or not. The return value check optimization though means our mock
override won't have the right effect. The mock will be invoked, but
its return value is not used.
Potentially the same problem could be exhibited with GCC if certain
combinations of optimizations are enabled, though thus far we've
not seen it.
To be robust on both CLang and GCC we need to make it more explicit
that we want to be able to replace functions and thus optimization
of calls must be limited. Currently we rely on 'noinline' which
does successfully prevent inlining of the function, but it cannot
stop the eliding of checks based on the constant return value.
Thus we need a bigger hammer.
There are a couple of options to disable this optimization:
* Annotate a symbol as 'weak'. This is tells the compiler
that the symbol is intended to be overridable at linktime
or runtime, and thus it will avoid doing inter-procedural
analysis for optimizations. This was tried previously but
have to be reverted as it had unintended consequences
when linking .a files into our final .so, resulting in all
the weak symbol impls being lost. See commit 407a281a8e2b6c5078ba1148535663ea64fd9314
* Annotate a symbol with 'noipa'. This tells the compiler
to avoid inter-procedural analysis for calls to just this
function. This would be ideal match for our scenario, but
unfortunately it is only implemented for GCC currently:
* The '-fsemantic-interposition' argument tells the optimizer
that any functions may be replaced with alternative
implementations that have different semantics. It thus
blocks any optimizations across function calls. This is
quite a harsh block on the optimizer, but it appears to be
the only one that is viable with CLang.
Out of those choices option (3) is the only viable option for
CLang. We don't want todo it for GCC though as it is such a
big hammer. Probably we should apply (2) for GCC, should we
experiance a problem in future.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Ján Tomko [Fri, 17 Mar 2023 13:58:23 +0000 (14:58 +0100)]
qemu: use correct formatting string for size_t
Otherwise the build on armv7l breaks:
error: format ‘%lu’ expects argument of type
‘long unsigned int’, but argument 4 has type
‘size_t’ {aka ‘unsigned int’} [-Werror=format=]
Fixes: 1992ae40fac90c315d0d8d1a9c6f880bd0a39b57 Fixes: e239f7d0a86ebddf9aab3f8c8e6b6e66351485b2 Signed-off-by: Ján Tomko <jtomko@redhat.com>
Or Ozeri [Mon, 13 Mar 2023 09:50:23 +0000 (04:50 -0500)]
qemu: add luks-any encryption support for RBD images
The newly added luks-any rbd encryption format in qemu
allows for opening both LUKS and LUKS2 encryption formats.
This commit enables libvirt uses to use this wildcard format.
Signed-off-by: Or Ozeri <oro@il.ibm.com> Reviewed-by: Peter Krempa <pkrempa@redhat.com>
This capability represents that qemu supports the "luks-any" encryption
format for RBD images.
Both LUKS and LUKS2 formats can be parsed using this wildcard format.
Signed-off-by: Or Ozeri <oro@il.ibm.com> Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Or Ozeri [Mon, 13 Mar 2023 09:50:21 +0000 (04:50 -0500)]
qemu: add support for librbd layered encryption
This commit enables libvirt users to use layered encryption
of RBD images, using the librbd encryption engine.
This allows opening of an encrypted cloned image
whose parent is encrypted with a possibly different encryption key.
To open such images, multiple encryption secrets are expected
to be defined under the encryption XML tag.
Signed-off-by: Or Ozeri <oro@il.ibm.com> Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Or Ozeri [Mon, 13 Mar 2023 09:50:20 +0000 (04:50 -0500)]
qemu: add multi-secret support in _qemuDomainStorageSourcePrivate
This commit changes the _qemuDomainStorageSourcePrivate struct
to support multiple secrets (instead of a single one before this commit).
This will useful for storage encryption requiring more than a single secret.
Signed-off-by: Or Ozeri <oro@il.ibm.com> Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Or Ozeri [Mon, 13 Mar 2023 09:50:19 +0000 (04:50 -0500)]
qemu: add multi-secret support in qemuBlockStorageSourceAttachData
This commit changes the qemuBlockStorageSourceAttachData struct
to support multiple secrets (instead of a single one before this commit).
This will useful for storage encryption requiring more than a single secret.
Signed-off-by: Or Ozeri <oro@il.ibm.com> Reviewed-by: Peter Krempa <pkrempa@redhat.com>
This capability represents that qemu supports the layered encryption
of RBD images, where a cloned image is encrypted with a possible
different encryption than its parent image.
Signed-off-by: Or Ozeri <oro@il.ibm.com> Reviewed-by: Peter Krempa <pkrempa@redhat.com>
When a thread-context object is specified on the cmd line, then
QEMU spawns a thread and sets its affinity to the list of NUMA
nodes specified in .node-affinity attribute. And this works just
fine, until the main QEMU thread itself is not restricted.
Because of v5.3.0-rc1~18 we restrict the main emulator thread
even before QEMU is executed and thus then it tries to set
affinity of a thread-context thread, it inevitably fails with:
Setting CPU affinity failed: Invalid argument
Now, we could lift the pinning temporarily, let QEMU spawn all
thread-context threads, and enforce pinning again, but that would
require some form of communication with QEMU (maybe -preconfig?).
But that would still be wrong, because it would circumvent
<emulatorpin/>.
Technically speaking, thread-context is an internal
implementation detail of QEMU, and if it weren't for it, the main
emulator thread would be doing the allocation. Therefore, we
should honor the pinning and prune the list of node so that
inaccessible ones are dropped.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2154750 Signed-off-by: Michal Privoznik <mprivozn@redhat.com> Reviewed-by: Kristina Hanicova <khanicov@redhat.com> Reviewed-by: Andrea Bolognani <abologna@redhat.com>
qemu: Add @nodemask argument to qemuBuildThreadContextProps()
When building a thread-context object (inside of
qemuBuildThreadContextProps()) we look at given memory-backend-*
object and look for .host-nodes attribute. This works, as long as
we need to just copy the attribute value into another
thread-context attribute. But soon we will need to adjust it.
That's the point where having the value in virBitmap comes handy.
Utilize the previous commit, which made
qemuBuildMemoryBackendProps() set the argument and pass it into
qemuBuildThreadContextProps().
Signed-off-by: Michal Privoznik <mprivozn@redhat.com> Reviewed-by: Kristina Hanicova <khanicov@redhat.com> Reviewed-by: Andrea Bolognani <abologna@redhat.com>
qemu: Add @nodemaskRet argument to qemuBuildMemoryBackendProps()
While it's true that anybody who's interested in getting
.host-nodes attribute value can just use
virJSONValueObjectGetArray() (and that's exactly what
qemuBuildThreadContextProps() is doing, btw), if somebody is
interested in getting the actual virBitmap, they would have to
parse the JSON array.
Instead, introduce an argument to qemuBuildMemoryBackendProps()
which is set to corresponding value used when formatting the
attribute.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com> Reviewed-by: Kristina Hanicova <khanicov@redhat.com> Reviewed-by: Andrea Bolognani <abologna@redhat.com>