March 2026 - Devel - libvirt List Archives

[PATCH v2 00/21] qom: introduce property flags to track external user input
by Zhao Liu 17 Mar '26

17 Mar '26

Hi, This is the v2 trying to introduce property flags to detect user's property setting (from CLI/QMP/HMP). I dropped RFC tag since previous RFC v1 [1]. Though this work the follow-up of v2.6 & v2.7 machines' removal [2], now it is decoupled from [2] totally since v2 doesn't detect compat property and only focuses on external user setting, so this series is based on master branch at the commit 28a6ca268c2c ("Merge tag 'single- binary-20260203' of https://github.com/philmd/qemu into staging"). And you can also find the code here: https://gitlab.com/zhao.liu/qemu/-/tree/prop-flags-v2.3-02-08-2026 This series introduces 3 property flags: * USER_SET: Any external user property setting (from CLI/HMP/QMP) is marked as USER_SET. * DEPRECATED: Once a property is marked as DEPRECATED, any external user property setting will trigger a warning. * INTERNAL: Once a property is marked as INTERNAL, any external user property setting will cause an error. More details or document for these 3 flags, you can refer patch 7. Compared with RFC v1, v2 mainly: * introduce USER_SET property flag to identify all user's setting. - patch 7 for document. * construct DEPRECATED & INTERNAL flag on USER_SET. - patch 7 for document. * cover more comprehensive user set cases. - patch 8-13. * provide examples about new flags (USER_SET/DEPRECATED/INTELNAL). - patch 15/16/17 are examples for DEPRECATED flag. - patch 18 is the example for INTERNAL flag. - patch 20 is the example for USER_SET flag. I think v2 should now cover "nearly" all cases (patch 8-13) where users set properties: one approach is to trace the call chain of object_property_set(). Even if there are cases that were missed, they can be easily addressed based on this series: object_property_set(obj, ...); /* Insert this call after object_property_set(). */ object_property_set_flags(obj, ..., OBJ_PROP_FLAG_USER_SET, ...); [1]: RFC v1: https://lore.kernel.org/qemu-devel/20251202170502.3228625-1-zhao1.liu@intel… [2]: hw/i386/pc: Remove deprecated 2.6 and 2.7 PC machines https://lore.kernel.org/qemu-devel/20260108033051.777361-1-zhao1.liu@intel.… Thanks and Best Regards, Zhao --- Zhao Liu (21): qom/object: use BIT macro for ObjectPropertyFlags qom/object: cache ObjectPropertyFlags in ObjectProperty qom/object: factor out object_class_property_try_add() qom/object: add flags argument in object_{class_}property_try_add() qom/object: rename object_{class_}property_try_add() to object_{class_}property_add_full() qom/object: add helpers to set/get/clear property flags qom/object: introduce user interaction flags for properties qom/object: add from_user argument in object_property_parse() qom/object: mark global property set from CLI as USER_SET qom/qom-hmp-cmd: mark properties set from HMP (non-JSON) "qom-set" as USER_SET qom/qom-qmp-cmd: mark properties set from QMP/HMP (JSON) "qom-set" as USER_SET qom/object_interfaces: mark properties set from qdict & keyval as USER_SET system/vl: mark property set in object_parse_property_opt() as USER_SET hw/core/qdev-properties: allow qdev properties accept flags target/i386: deprecate fill-mtrr-mask property target/i386: deprecate cpuid-0xb property hw/intc/ioapic: deprecate version property target/i386: mark x-consistent-cache property as internal-only target/i386: remove redundant validation for lbr-fmt property target/i386: detect user provided lbr-fmt via property flag hw/core/qdev-properties: support valid default value for DEFINE_PROP_UINT64_CHECKMASK docs/about/deprecated.rst | 31 +++++ hw/core/qdev-properties.c | 29 ++-- hw/i386/sgx.c | 2 +- hw/intc/ioapic.c | 3 +- include/hw/core/qdev-properties.h | 38 +++--- include/qom/object.h | 215 +++++++++++++++++++++++++++--- qom/object.c | 177 ++++++++++++++++++++---- qom/object_interfaces.c | 5 + qom/qom-hmp-cmds.c | 2 +- qom/qom-qmp-cmds.c | 7 +- system/vl.c | 6 +- target/i386/cpu.c | 28 ++-- 12 files changed, 448 insertions(+), 95 deletions(-) -- 2.34.1

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A few questions about libvirt-java
by Takashi Kajinami 15 Mar '26

15 Mar '26

Hi, I've been working in a downstream project using libvirt-java to manage resources in libvirt from our application written in Java. The library has been working well so far, but I'm interested in contributing further improvements of the library, such as; - Replace finalize by more modern mechanisms such as (Auto)Closeable (finalize is deprecated in recent OpenJDK versions) - Complete migration to maven (to get rid of maven-ant-tasks which was already retired) However some of the planned contributions (especially the ones listed above) have relatively large impact and I'd like to ask a few questions so that so that we can drive the effort more smoothly. 1. Do you think that these are good/reasonable improvements ? 2. May I request a new release ? The last release (0.5.3) was released 4 years ago and several changes such as new features have been merged since then. Creating a release allows us to mave backword incompatible changes with less user impact. 3. Can we bump minimum JDK version ? Current minimum JSK version supported by the library is 1.8.0 but this is quite old ELS. I wonder if we can bump it to a newer version such as OpenJDK 17 or even 21. This is required to replace "finalize". Is there requirement about the platform the library should support ? Any feedback or guidance is very much appreciated ! Thank you, Takashi -- Takashi Kajinami irc: tkajinam github: https://github.com/kajinamit launchpad: https://launchpad.net/~kajinamit

1 0

[PATCH] virt-aa-helper: Prevent spurious denials for AoE disks
by PUSHKARAJ PATIL 14 Mar '26

14 Mar '26

virt-aa-helper calls virStorageSourceGetMetadata before adding a disk path to a domain's apparmor profile. This probes the device and may trigger an AppArmor denial when the disk is an AoE device under /dev/etherd/. The return value of virStorageSourceGetMetadata is not checked, so the denial has no functional impact but results in noisy dmesg logs. Allow read access to /dev/etherd/e*.* in the virt-aa-helper profile to avoid these spurious denials. Signed-off-by: PUSHKARAJ PATIL <pushkaraj.patil(a)in.ibm.com> --- src/security/apparmor/usr.lib.libvirt.virt-aa-helper.in | 1 + 1 file changed, 1 insertion(+) diff --git a/src/security/apparmor/usr.lib.libvirt.virt-aa-helper.in b/src/security/apparmor/usr.lib.libvirt.virt-aa-helper.in index e209a8bff7..80e9ef2b08 100644 --- a/src/security/apparmor/usr.lib.libvirt.virt-aa-helper.in +++ b/src/security/apparmor/usr.lib.libvirt.virt-aa-helper.in @@ -73,6 +73,7 @@ profile virt-aa-helper @libexecdir@/virt-aa-helper { /**.vhd r, /**.[iI][sS][oO] r, /**/disk{,.*} r, + /dev/etherd/e*.* r, include if exists <local/usr.lib.libvirt.virt-aa-helper> } -- 2.50.1 (Apple Git-155)

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[PATCH 0/4] libvirt: AMD IOMMU fixes
by Xiaotian Feng 14 Mar '26

14 Mar '26

This series refines libvirt's logic for large vCPU configurations (>255) on x86/q35 machine types. Historically, the threshold was tied to Intel's EIM capability, but the real requirement is x2APIC support for APIC IDs beyond 255. AMD platforms can satisfy this via xtsup on amd-iommu. Summary of changes: 1. Fix virDomainIOMMUDefEquals to include pt and xtsup attributes for proper checks. 2. Correct error messages for passthrough (pt) and xtsup attributes to reflect their actual names instead of "dma translation". 3. Rename QEMU_MAX_VCPUS_WITHOUT_EIM to QEMU_MAX_VCPUS_WITHOUT_X2APIC and update validation logic to accept either: - intel-iommu with eim='on', or - amd-iommu with xtsup='on' for guests with more than 255 vCPUs. Error messages now mention x2APIC mode instead of extended interrupt mode. 4. Add QEMU_CAPS_AMD_IOMMU_XTSUP capability and enable xtsup by default for AMD IOMMU when a Q35 domain has >255 vCPUs, similar to Intel EIM auto-enable logic. Also ensure intremap is turned on when required. This makes the behavior vendor-neutral and improves usability for AMD EPYC guests with large vCPU counts. No ABI changes beyond stricter equality checks; this is a clarification and extension of existing logic. Xiaotian Feng (4): conf: fix virDomainIOMMUDefEquals for amd_iommu conf: fix error log for passthrough and xtsup attributes conf: support >255 vcpu w/ amd-iommu xtsup qemu: Enable AMD IOMMU XTSUP by default src/conf/domain_conf.c | 6 ++++-- src/qemu/qemu_capabilities.c | 2 ++ src/qemu/qemu_capabilities.h | 1 + src/qemu/qemu_postparse.c | 42 +++++++++++++++++++++++------------- src/qemu/qemu_validate.c | 11 +++++----- src/qemu/qemu_validate.h | 2 +- 6 files changed, 41 insertions(+), 23 deletions(-) -- 2.34.1

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[PATCH] storage: mpath: fix error reporting in virStorageBackendGetMaps
by Lucas Amaral 14 Mar '26

14 Mar '26

virStorageBackendGetMaps() returns 1 on failure instead of the conventional -1, and does not call virReportError() in any of its error paths. On top of that, both callers silently discard the return value: virStorageBackendGetMaps() ignores the result of virStorageBackendCreateVols(), and virStorageBackendMpathRefreshPool() ignores the result of virStorageBackendGetMaps(). Fix all three issues: normalize error returns to -1, add virReportError() calls for each failure path in virStorageBackendGetMaps(), and check return values in both callers so that errors are properly propagated. Signed-off-by: Lucas Amaral <lucaaamaral(a)gmail.com> --- This is similar in spirit to commits e9b931d3e4 ("virpci: Report an error if virPCIGetVirtualFunctionIndex() fails") and 6c2c9e21ac ("virstorageobj: Make virStoragePoolObjAddVol() report an error on failure"), applying the same pattern to the mpath storage backend. Found while auditing storage backends for functions that return error codes without calling virReportError(). src/storage/storage_backend_mpath.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) diff --git a/src/storage/storage_backend_mpath.c b/src/storage/storage_backend_mpath.c index 9fc3983c52..a30153a93b 100644 --- a/src/storage/storage_backend_mpath.c +++ b/src/storage/storage_backend_mpath.c @@ -197,19 +197,25 @@ virStorageBackendGetMaps(virStoragePoolObj *pool) struct dm_names *names = NULL; if (!(dmt = dm_task_create(DM_DEVICE_LIST))) { - retval = 1; + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("Failed to create devmapper task")); + retval = -1; goto out; } dm_task_no_open_count(dmt); if (!dm_task_run(dmt)) { - retval = 1; + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("Failed to run devmapper task")); + retval = -1; goto out; } if (!(names = dm_task_get_names(dmt))) { - retval = 1; + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("Failed to get devmapper device names")); + retval = -1; goto out; } @@ -218,7 +224,10 @@ virStorageBackendGetMaps(virStoragePoolObj *pool) goto out; } - virStorageBackendCreateVols(pool, names); + if (virStorageBackendCreateVols(pool, names) < 0) { + retval = -1; + goto out; + } out: if (dmt != NULL) @@ -248,7 +257,8 @@ virStorageBackendMpathRefreshPool(virStoragePoolObj *pool) virWaitForDevices(); - virStorageBackendGetMaps(pool); + if (virStorageBackendGetMaps(pool) < 0) + return -1; return 0; } -- 2.52.0

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[PATCH 1/1] qemu: fix potential hang in qemuMigrationSrcCancel during reconnect
by Denis V. Lunev 13 Mar '26

13 Mar '26

When libvirtd reconnects to a running QEMU process that had an in-progress migration, qemuProcessReconnect first connects the monitor and only later recovers the migration job. During this window the async job is VIR_ASYNC_JOB_NONE, so any MIGRATION status events from QEMU are silently dropped by qemuProcessHandleMigrationStatus. If the migration was already cancelled or completed by QEMU during this window, no further events will be emitted. When qemuMigrationSrcCancelUnattended later restores the async job and calls qemuMigrationSrcCancel with wait=true, the wait loop calls qemuDomainObjWait (virCondWait with no timeout) and blocks forever waiting for an event that will never arrive. Fix this by querying QEMU migration status with query-migrate immediately after sending migrate_cancel, while still inside the monitor session. This ensures the job's migration status is up to date before entering the wait loop, so if QEMU already reached a terminal state (cancelled/completed/error), the loop exits immediately. Signed-off-by: Denis V. Lunev <den(a)openvz.org> CC: Peter Krempa <pkrempa(a)redhat.com> CC: Michal Privoznik <mprivozn(a)redhat.com> --- src/qemu/qemu_migration.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c index fec808ccfb..3a9185f65c 100644 --- a/src/qemu/qemu_migration.c +++ b/src/qemu/qemu_migration.c @@ -4876,6 +4876,21 @@ qemuMigrationSrcCancel(virDomainObj *vm, return -1; rc = qemuMonitorMigrateCancel(priv->mon); + + if (rc == 0 && wait) { + virDomainJobData *jobData = vm->job->current; + qemuDomainJobDataPrivate *privJob = jobData->privateData; + qemuMonitorMigrationStats stats; + + /* During reconnect the async job is not yet restored when migration + * events can arrive from QEMU, causing + * qemuProcessHandleMigrationStatus() to drop them. In that case + * QEMU won't send any more events and the wait loop would block + * forever. */ + if (qemuMonitorGetMigrationStats(priv->mon, &stats, NULL) == 0) + privJob->stats.mig.status = stats.status; + } + qemuDomainObjExitMonitor(vm); if (rc < 0) -- 2.51.0

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[libvirt PATCH] viriommufd: Set IOMMU_OPTION_RLIMIT_MODE only when running privileged
by Pavel Hrdina 13 Mar '26

13 Mar '26

From: Pavel Hrdina <phrdina(a)redhat.com> If libvirt daemon is running unprivileged it will fail so we should not even try to set it. Signed-off-by: Pavel Hrdina <phrdina(a)redhat.com> --- src/qemu/qemu_process.c | 2 +- src/util/viriommufd.c | 6 +++--- src/util/viriommufd.h | 2 +- 3 files changed, 5 insertions(+), 5 deletions(-) diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c index ab7cf03c0e..ecd05b4bf6 100644 --- a/src/qemu/qemu_process.c +++ b/src/qemu/qemu_process.c @@ -7732,7 +7732,7 @@ qemuProcessOpenIommuFd(virDomainObj *vm) VIR_DEBUG("Opening IOMMU FD for domain %s", vm->def->name); - if ((iommufd = virIOMMUFDOpenDevice()) < 0) + if ((iommufd = virIOMMUFDOpenDevice(priv->driver->privileged)) < 0) return -1; if (qemuSecuritySetImageFDLabel(priv->driver->securityManager, vm->def, iommufd) < 0) diff --git a/src/util/viriommufd.c b/src/util/viriommufd.c index b62d59241d..82920923a2 100644 --- a/src/util/viriommufd.c +++ b/src/util/viriommufd.c @@ -80,14 +80,14 @@ virIOMMUFDSetRLimitMode(int fd, bool processAccounting) } int -virIOMMUFDOpenDevice(void) +virIOMMUFDOpenDevice(bool privileged) { int fd = -1; if ((fd = open(VIR_IOMMU_DEV_PATH, O_RDWR | O_CLOEXEC)) < 0) virReportSystemError(errno, "%s", _("cannot open IOMMUFD device")); - if (virIOMMUFDSetRLimitMode(fd, true) < 0) { + if (privileged && virIOMMUFDSetRLimitMode(fd, true) < 0) { VIR_FORCE_CLOSE(fd); return -1; } @@ -98,7 +98,7 @@ virIOMMUFDOpenDevice(void) #else int -virIOMMUFDOpenDevice(void) +virIOMMUFDOpenDevice(bool privileged G_GNUC_UNUSED) { virReportError(VIR_ERR_NO_SUPPORT, "%s", _("IOMMUFD is not supported on this platform")); diff --git a/src/util/viriommufd.h b/src/util/viriommufd.h index 223f44eb5c..7bad5c7472 100644 --- a/src/util/viriommufd.h +++ b/src/util/viriommufd.h @@ -22,6 +22,6 @@ #define VIR_IOMMU_DEV_PATH "/dev/iommu" -int virIOMMUFDOpenDevice(void); +int virIOMMUFDOpenDevice(bool privileged); bool virIOMMUFDSupported(void); -- 2.53.0

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[PATCH 0/5] hyperv: Implement basic snapshot query APIs
by Jonathon Jongsma 13 Mar '26

13 Mar '26

This is the first patch series adding snapshot support for the hyperv driver. It only implements the basic functions for querying information about snapshots and doesn't handle creating or deleting snapshots yet. Jonathon Jongsma (5): hyperv: Implement domainSnapshotLookupByName() hyperv: implement virDomainListAllSnapshots()/virDomainSnapshotNum() hyperv: implement virDomainSnapshotGetXMLDesc() hyperv: Implement virDomainSnapshotCurrent()/virDomainHasCurrentSnapshot() hyperv: Implement virDomainSnapshotGetParent() src/hyperv/hyperv_driver.c | 276 +++++++++++++++++++++++++++++++++++++ src/hyperv/hyperv_wmi.c | 20 +++ src/hyperv/hyperv_wmi.h | 7 + 3 files changed, 303 insertions(+) -- 2.53.0

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virsh feature request: cold restart and/or synchronous shutdown option
by roy-orbitson＠devo.net.au 13 Mar '26

13 Mar '26

When libvirt components get updated on a hypervisor, VMs continue running with obsolete files. Programs like "needrestart" alert one to this condition with messages like: VM guests are running outdated hypervisor (qemu) binaries on this host: 'bazquux' with pid 1234 Normal restarting of a VM (from within or with `virsh reboot ...`) does not resolve it because it's 'warm'; VMs must be completely shut down then started again to utilise the updates. Afaik, to do so reliably, in a way that minimises downtime, requires scripts like this: (d=bazquux; virsh shutdown --domain "$d" && until LC_ALL=C LANG=C virsh domstate --domain "$d" | grep -Fi 'shut off' &> /dev/null; do echo ...; sleep 1; done && virsh start --domain "$d") Adding a timeout complicates that further. Options for this logic to be performed by virsh would be beneficial, as a single operation: virsh reboot --domain bazquux --cold And by allowing poweroff to wait: (d=bazquux; virsh shutdown --domain "$d" --synchronous && virsh start --domain "$d") The latter would also assist with scripting changes to a VM that can only be performed whilst it is not running (shutdown -> alter -> start). Ideally, these would accept `--timeout n` so that if the shutdown portion was not completed quickly enough, they would fail and exit with a non-zero status, and the former would not start the VM again. I'm not sure of a good way to handle this where `on_poweroff` is set to something that doesn't result in the machine being shut off.

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[PATCH v1 0/1] rpc: fix virNetClient->error leak on teardown
by Leander Kohler 12 Mar '26

12 Mar '26

Hi all, this is my first contribution to libvirt upstream. I am with Cyberus Technology, where I work on cloud-hypervisor and its integration with OpenStack and libvirt. The following fixes a leak in virNetClient teardown. virNetClientMarkClose() may save the current error in client->error (via virSaveLastError()). We usually free that in virNetClientCloseLocked(), but we can also end up disposing the client without going through that cleanup. One path where this happens is: virConnectDispose() -> remoteConnectClose() -> doRemoteClose() -> virNetClientClose(priv->client) -> g_clear_pointer(&priv->client, virObjectUnref) In that case, client->error can stay allocated until finalization, and ASan reports a leak. Fix is to also clear client->error in virNetClientDispose() as a final fallback. I included an ASan trace below. Thanks, Leander --- Line numbers in this trace come from our downstream libvirt fork and may differ from upstream, but the call path/function names are the same. [ 276.247727] virtchd[4030]: ==4030==ERROR: LeakSanitizer: detected memory leaks Direct leak of 80 byte(s) in 1 object(s) allocated from: #0 0x7fcd6009e110 in calloc (libasan.so.8+0xfc110) #1 0x7fcd5dcb95bd in g_malloc0 (libglib-2.0.so.0+0x6d5bd) #2 0x7fcd5eb15f31 in virSaveLastError ../src/util/virerror.c:413 #3 0x7fcd5ee6c76c in virNetClientMarkClose ../src/rpc/virnetclient.c:776 #4 0x7fcd5ee6f782 in virNetClientCloseInternal ../src/rpc/virnetclient.c:837 #5 0x7fcd5f0150e4 in doRemoteClose ../src/remote/remote_driver.c:1414 #6 0x7fcd5f0150e4 in remoteConnectClose ../src/remote/remote_driver.c:1442 #7 0x7fcd5f1a90ef in virConnectDispose ../src/datatypes.c:174 #8 0x7fcd5ea58ebb in vir_object_finalize ../src/util/virobject.c:323 #9 0x7fcd5dc05c52 in g_object_unref (libgobject-2.0.so.0+0x1ec52) #10 0x7fcd5ea59fc7 in virObjectUnref ../src/util/virobject.c:377 #11 0x7fcd5ea59fc7 in virObjectUnref ../src/util/virobject.c:370 #12 0x7fcd5ef3a92f in glib_autoptr_clear_virConnect ../src/datatypes.h:548 #13 0x7fcd5ef3a92f in glib_autoptr_cleanup_virConnect ../src/datatypes.h:548 #14 0x7fcd5ef3a92f in virDomainInterfaceDeleteDevice ../src/hypervisor/domain_interface.c:419 #15 0x7fcd594a0cd3 in virCHProcessStopOrKill ../src/ch/ch_process.c:1308 #16 0x7fcd594a8bfa in virCHProcessStop ../src/ch/ch_process.c:1363 #17 0x7fcd5945d8c7 in chDomainDestroyFlags ../src/ch/ch_driver.c:959 #18 0x7fcd5f0f69c0 in virDomainDestroy ../src/libvirt-domain.c:514 #19 0x55c25777376a in remoteDispatchDomainDestroy src/remote/remote_daemon_dispatch_stubs.h:5485 #20 0x55c25777376a in remoteDispatchDomainDestroyHelper src/remote/remote_daemon_dispatch_stubs.h:5464 #21 0x7fcd5ee7c42c in virNetServerProgramDispatchCall ../src/rpc/virnetserverprogram.c:423 #22 0x7fcd5ee7c42c in virNetServerProgramDispatch ../src/rpc/virnetserverprogram.c:299 #23 0x7fcd5ee97c6c in virNetServerProcessMsg ../src/rpc/virnetserver.c:135 #24 0x7fcd5ee98b43 in virNetServerHandleJob ../src/rpc/virnetserver.c:155 #25 0x7fcd5eadbce2 in virThreadPoolWorker ../src/util/virthreadpool.c:164 #26 0x7fcd5eada3c9 in virThreadHelper ../src/util/virthread.c:256 #27 0x7fcd60004cd5 in asan_thread_start(void*) (libasan.so.8+0x62cd5) #28 0x7fcd5d200979 in start_thread (libc.so.6+0x9a979) #29 0x7fcd5d288d2b in __GI___clone3 (libc.so.6+0x122d2b) Objects leaked above: 0x507000064400 (80 bytes) SUMMARY: AddressSanitizer: 80 byte(s) leaked in 1 allocation(s). Leander Kohler (1): rpc: free saved close error in virNetClientDispose src/rpc/virnetclient.c | 2 ++ 1 file changed, 2 insertions(+) -- 2.51.2

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