February 2026 - Devel - libvirt List Archives

[PATCH v2 00/21] qom: introduce property flags to track external user input
by Zhao Liu 23 Mar '26

23 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

9 44

[RFC] Reintroducing customisable hotplug timeouts
by Akash Kulhalli 23 Mar '26

23 Mar '26

I'd like to resurface an earlier proposal [1] to make the unplug timeout user-configurable. With production guests running sustained, non-trivial workloads, we find that hot(un)plug operations regularly takes longer than the current default of 5s. However, the inability to easily configure this timeout means that in the worst case a recompilation with appropriate values set is required for each deployment, which is cumbersome to maintain and patch. The previous proposal [1] also initially made the timeout configurable, however that was specifically for the ppc64 architecture. Therefore, imposing this change for an entire architecture made sense, since it was a universal requirement for that platform. With deployment environments as diverse and varied as x86, having a single, inconfigurable value does not make as much sense now. For x86, such a change is not ideal since the desired timeout value depends very heavily on the deployment environment in use - if it is being performed by a human anything more than 10s is an undesirable user experience [2], as pointed out in the original discussion. However, more relaxed timeout values (e.g. 15-20s) can be more acceptable if the operations are background/ not directly user-facing. It is in these cases where the ability to change the timeout more easily becomes more desirable. To prevent misconfiguration, while maintaining the same out-of-box experience for existing users, I'd also like to propose the following- 1. As mentioned in the original proposal [1], the timeout cannot be set to a value lower than the default timeout of 5s; in these cases a warning will be emitted and the timeout will be reset to the default value. 2. Including an upper cap would also be desirable, in my opinion - any API consumer should not wait endlessly for an async operation to finish. 3. This configuration option will only be described in qemu.conf, not imposed - the out-of-box experience will remain unchanged at the current default (5s) for everyone who does not wish to tweak/is unaware of this value. An administrator who knowingly changes these values is therefore not blindsided by any perceived "hangs" resulting from the use of an increased timeout window. Since this would be a clearly documented and explicitly opt-in behaviour, the benefits in the form of easy modification based on evolving operational needs would be quite significant. Given the varying nature of production environments and specific operational needs at scale, it would therefore be beneficial to reconsider the merits of the original proposal. [1] https://lists.libvirt.org/archives/list/devel@lists.libvirt.org/thread/TXYV… [2] https://www.nngroup.com/articles/response-times-3-important-limits/

4 9

[PATCH] qemu: migration: Call hook script on source host at migration start
by Guy Godfroy 21 Mar '26

21 Mar '26

Currently, the qemu hook script with the "migrate" operation is only called on the destination host at the beginning of incoming migration. This makes it impossible for the source host to prepare for migration, for example to change storage locks from exclusive to shared mode when using shared LVM storage with lvmlockd. Add a hook call on the source host at the beginning of outgoing migration. The hook is called with "source" as the extra argument to distinguish it from the destination hook which uses "-". The same change is also applied to the libxl driver for consistency. Resolves: https://gitlab.com/libvirt/libvirt/-/issues/37 Signed-off-by: Guy Godfroy <guy.godfroy(a)gugod.fr> --- docs/hooks.rst | 36 ++++++++++++++++++++++++++++++++---- src/libxl/libxl_migration.c | 17 +++++++++++++++++ src/qemu/qemu_migration.c | 17 +++++++++++++++++ 3 files changed, 66 insertions(+), 4 deletions(-) diff --git a/docs/hooks.rst b/docs/hooks.rst index e1745b8cc7..4c7cac56ba 100644 --- a/docs/hooks.rst +++ b/docs/hooks.rst @@ -244,7 +244,7 @@ operation. There is no specific operation to indicate a "restart" is occurring. - :since:`Since 0.9.11`, the qemu hook script is also called at the beginning - of incoming migration. It is called as: + of incoming migration on the **destination** host. It is called as: :: @@ -257,6 +257,18 @@ operation. There is no specific operation to indicate a "restart" is occurring. is not valid, incoming migration will be canceled. This hook may be used, e.g., to change location of disk images for incoming domains. +- :since:`Since 12.1.0`, the qemu hook script is also called at the beginning + of outgoing migration on the **source** host. It is called as: + + :: + + /etc/libvirt/hooks/qemu guest_name migrate begin source + + with domain XML sent to standard input of the script. Unlike the destination + hook, this script does not act as a filter and any output is ignored. If the + script returns failure, the migration will be canceled. This hook may be used, + e.g., to change storage lock mode from exclusive to shared before migration. + - :since:`Since 1.2.9`, the qemu hook script is also called when restoring a saved image either via the API or automatically when restoring a managed save machine. It is called as: @@ -417,7 +429,7 @@ operation. There is no specific operation to indicate a "restart" is occurring. /etc/libvirt/hooks/libxl guest_name release end - - :since:`Since 2.1.0`, the libxl hook script is also called at the beginning - of incoming migration. It is called as: + of incoming migration on the **destination** host. It is called as: :: @@ -430,6 +442,18 @@ operation. There is no specific operation to indicate a "restart" is occurring. is not valid, incoming migration will be canceled. This hook may be used, e.g., to change location of disk images for incoming domains. +- :since:`Since 12.1.0`, the libxl hook script is also called at the beginning + of outgoing migration on the **source** host. It is called as: + + :: + + /etc/libvirt/hooks/libxl guest_name migrate begin source + + with domain XML sent to standard input of the script. Unlike the destination + hook, this script does not act as a filter and any output is ignored. If the + script returns failure, the migration will be canceled. This hook may be used, + e.g., to change storage lock mode from exclusive to shared before migration. + - :since:`Since 6.5.0`, you can also place several hook scripts in the directory ``/etc/libvirt/hooks/libxl.d/``. They are executed in alphabetical order after main script. In this case each script also acts as filter and can @@ -566,10 +590,14 @@ Migration of a QEMU guest involves running hook scripts on both the source and destination hosts: #. At the beginning of the migration, the *qemu* hook script on the - **destination** host is executed with the "migrate" operation. + **source** host is executed with the "migrate" operation and "source" + as the extra argument (:since:`since 12.1.0`). This allows the source + host to prepare for migration, e.g., changing storage locks. +#. Then, the *qemu* hook script on the **destination** host is executed + with the "migrate" operation. #. Before QEMU process is spawned, the two operations ("prepare" and "start") called for domain start are executed on **destination** host. -#. If both of these hook script executions exit successfully (exit status 0), +#. If all of these hook script executions exit successfully (exit status 0), the migration continues. Any other exit code indicates failure, and the migration is aborted. #. The QEMU guest is then migrated to the destination host. diff --git a/src/libxl/libxl_migration.c b/src/libxl/libxl_migration.c index f5dee7627b..76f3c7ceb7 100644 --- a/src/libxl/libxl_migration.c +++ b/src/libxl/libxl_migration.c @@ -411,6 +411,23 @@ libxlDomainMigrationSrcBegin(virConnectPtr conn, if (!libxlDomainMigrationIsAllowed(def)) goto endjob; + /* Call hook to allow source host to prepare for migration */ + if (virHookPresent(VIR_HOOK_DRIVER_LIBXL)) { + g_autofree char *hookxml = NULL; + int hookret; + + if (!(hookxml = virDomainDefFormat(def, driver->xmlopt, + VIR_DOMAIN_DEF_FORMAT_SECURE))) + goto endjob; + + hookret = virHookCall(VIR_HOOK_DRIVER_LIBXL, def->name, + VIR_HOOK_LIBXL_OP_MIGRATE, VIR_HOOK_SUBOP_BEGIN, + "source", hookxml, NULL); + + if (hookret < 0) + goto endjob; + } + xml = virDomainDefFormat(def, driver->xmlopt, VIR_DOMAIN_DEF_FORMAT_SECURE); /* Valid xml means success! EndJob in the confirm phase */ if (xml) diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c index 6dd022163b..60e370319c 100644 --- a/src/qemu/qemu_migration.c +++ b/src/qemu/qemu_migration.c @@ -2791,6 +2791,23 @@ qemuMigrationSrcBeginPhase(virQEMUDriver *driver, if (!qemuMigrationSrcIsAllowed(vm, true, vm->job->asyncJob, flags)) return NULL; + /* Call hook to allow source host to prepare for migration */ + if (virHookPresent(VIR_HOOK_DRIVER_QEMU)) { + g_autofree char *xml = NULL; + int hookret; + + if (!(xml = qemuDomainDefFormatLive(driver, priv->qemuCaps, vm->def, + priv->origCPU, false, true))) + return NULL; + + hookret = virHookCall(VIR_HOOK_DRIVER_QEMU, vm->def->name, + VIR_HOOK_QEMU_OP_MIGRATE, VIR_HOOK_SUBOP_BEGIN, + "source", xml, NULL); + + if (hookret < 0) + return NULL; + } + if (!(flags & (VIR_MIGRATE_UNSAFE | VIR_MIGRATE_OFFLINE)) && !qemuMigrationSrcIsSafe(vm, migrate_disks, flags)) return NULL; -- 2.34.1

3 12

[PATCH v2 0/2] Adding support for client-based FD migrations.
by Tejus GK 20 Mar '26

20 Mar '26

Libvirt supports FD-based live migrations in the form of tunnelled migrations. However, this isn't as performant as of now, since it involves extra copies.· This patchset proposes adding support for externally provided file descriptors for live migration. By allowing the client to supply the migration FD directly, the extra copy can be avoided, improving overall migration performance. The intent is to gather early feedback on the approach and its feasibility. Comments, concerns, and suggestions are very welcome :) V2: 1. Removed the approach of introducing a new FD passing API and instead reuse the virDomainFDAssociate API along with a dummy VM on the destination host. 2. Introduced a new virDomainMigrate parameter, VIR_MIGRATE_PARAM_FD_SET. Tejus GK (2): qemu: support incoming "fd" uri qemu: add support for fd based live migrations include/libvirt/libvirt-domain.h | 14 +++ src/qemu/qemu_driver.c | 24 +++-- src/qemu/qemu_migration.c | 174 +++++++++++++++++++++++++------ src/qemu/qemu_migration.h | 3 + 4 files changed, 178 insertions(+), 37 deletions(-) -- 2.43.7

2 4

[PATCH 0/2] storage: fix pool refresh failure during async jobs
by Lucas Amaral 20 Mar '26

20 Mar '26

When creating multiple VMs in parallel using virt-install, pool refresh fails with: error: internal error: pool 'default' has asynchronous jobs running. This happens because a concurrent volume creation holds an async job on the pool. The storagePoolRefresh() function immediately returns VIR_ERR_INTERNAL_ERROR instead of waiting for the async job to finish. Patch 1 fixes the error code from VIR_ERR_INTERNAL_ERROR to VIR_ERR_OPERATION_INVALID in all 4 affected operations (pool-refresh, pool-destroy, pool-undefine, pool-delete), consistent with the adjacent "pool is not active" and "pool is starting up" checks. Patch 2 adds a condition variable to virStoragePoolObj so that storagePoolRefresh() waits up to 30 seconds for async jobs to drain instead of failing immediately. The other three operations keep the immediate error since waiting to destroy/delete/undefine a pool during volume creation is not a sensible user workflow. Reproducing the bug requires artificially widening the race window since fallocate() completes in microseconds on local filesystems. I used LD_PRELOAD to inject a 15-second delay into fallocate64() for files in the pool directory. Details and validation results are in the individual patch notes below the '---' line. https://issues.redhat.com/browse/RHEL-150758 Lucas Amaral (2): storage: fix error code for async jobs check in pool operations storage: wait for async jobs to drain during pool refresh src/conf/virstorageobj.c | 39 ++++++++++++++++++++++++++++++++++++ src/conf/virstorageobj.h | 3 +++ src/libvirt_private.syms | 1 + src/storage/storage_driver.c | 25 ++++++++++++++++------- 4 files changed, 61 insertions(+), 7 deletions(-) -- 2.52.0

2 5

[PATCH] qemu: add automatic port allocation for pull-mode backup NBD servers
by Lucas Amaral 20 Mar '26

20 Mar '26

Previously, users had to manually specify a TCP port when starting a pull-mode backup with an NBD server. A TODO comment in qemuBackupPrepare() noted this limitation and pointed toward using virPortAllocator, as done for migration, VNC, and SPICE ports. Add backup_port_min and backup_port_max configuration options to qemu.conf, defaulting to 10809-10872 (10809 is the IANA-assigned NBD port; range of 64 matches the migration port pattern). When a pull-mode backup is started without specifying a TCP port, a port is now acquired automatically from the configured range via virPortAllocatorAcquire(). The port is released when the backup ends or if startup fails. Signed-off-by: Lucas Amaral <lucaaamaral(a)gmail.com> --- Build-tested and passed full test suite on CentOS Stream 9 (298 OK, 0 failures). Runtime-validated against an actual patched virtqemud instance running inside a privileged container (CentOS Stream 9, QEMU 10.1.0) with a live aarch64/virt guest. Config parsing validation: - Default config (no backup_port_* set): daemon starts OK - Custom range (backup_port_min=20000, backup_port_max=20010): daemon starts OK - Invalid (min > max): daemon correctly refuses to start - Invalid (min = 0): daemon correctly refuses to start - Invalid (max > 65535): daemon correctly refuses to start Port auto-allocation (live VM backup): - Pull-mode backup WITHOUT port specified: backup-begin succeeds, backup-dumpxml shows auto-allocated port='10809' from default range. Previously this would fail with: "<domainbackup> must specify TCP port for now" - Pull-mode backup WITH explicit port=10809: backup-begin succeeds, backup-dumpxml shows port='10809'. Behavior unchanged from before the patch. Port conflict and exhaustion (range set to 10809-10810, 3 VMs): - Auto-allocate on vm1 (got 10809), then manual port=10809 on vm2: QEMU correctly rejects with "Address already in use" - Auto-allocate vm1=10809, vm2=10810 (range full), vm3 attempt: "Unable to find an unused port in range 'backup' (10809-10810)" - After aborting vm1 backup (releasing 10809), vm3 retries and gets 10809: port release and reuse works correctly docs/formatbackup.rst | 3 ++- src/qemu/libvirtd_qemu.aug | 2 ++ src/qemu/qemu.conf.in | 9 ++++++++ src/qemu/qemu_backup.c | 33 +++++++++++++++++++++--------- src/qemu/qemu_conf.c | 25 ++++++++++++++++++++++ src/qemu/qemu_conf.h | 6 ++++++ src/qemu/qemu_domain.h | 1 + src/qemu/qemu_driver.c | 6 ++++++ src/qemu/test_libvirtd_qemu.aug.in | 2 ++ 9 files changed, 76 insertions(+), 11 deletions(-) diff --git a/docs/formatbackup.rst b/docs/formatbackup.rst index df6392e3bd..24857eaf72 100644 --- a/docs/formatbackup.rst +++ b/docs/formatbackup.rst @@ -42,7 +42,8 @@ were supplied). The following child elements and attributes are supported: ```protocol`` element of a disk <formatdomain.html#hard-drives-floppy-disks-cdroms>`__ attached via NBD in the domain (such as transport, socket, name, port, or tls), necessary to set up an NBD server that exposes the content of each disk at - the time the backup is started. + the time the backup is started. For TCP transport, if ``port`` is omitted, a + port is allocated automatically from the range configured in ``/etc/libvirt/qemu.conf``. In addition to the above the NBD server used for backups allows using ``transport='fd' fdgroup='NAME'`` where ``NAME`` is the name used with diff --git a/src/qemu/libvirtd_qemu.aug b/src/qemu/libvirtd_qemu.aug index 0286582169..eb790d48be 100644 --- a/src/qemu/libvirtd_qemu.aug +++ b/src/qemu/libvirtd_qemu.aug @@ -146,6 +146,8 @@ module Libvirtd_qemu = | int_entry "migration_port_min" | int_entry "migration_port_max" | str_entry "migration_host" + | int_entry "backup_port_min" + | int_entry "backup_port_max" let log_entry = bool_entry "log_timestamp" diff --git a/src/qemu/qemu.conf.in b/src/qemu/qemu.conf.in index 2d1c67034d..5eacd70022 100644 --- a/src/qemu/qemu.conf.in +++ b/src/qemu/qemu.conf.in @@ -969,6 +969,15 @@ #migration_port_max = 49215 +# Port range used for automatic allocation of NBD backup server ports. +# When a pull-mode backup is started without specifying a TCP port, a +# port from this range will be assigned automatically. The NBD standard +# port is 10809. +# +#backup_port_min = 10809 +#backup_port_max = 10872 + + # Timestamp QEMU's log messages (if QEMU supports it) # # Defaults to 1. diff --git a/src/qemu/qemu_backup.c b/src/qemu/qemu_backup.c index 44514d08fc..12ef64b14e 100644 --- a/src/qemu/qemu_backup.c +++ b/src/qemu/qemu_backup.c @@ -32,6 +32,7 @@ #include "storage_source.h" #include "storage_source_conf.h" #include "virerror.h" +#include "virportallocator.h" #include "virlog.h" #include "virbuffer.h" #include "backup_conf.h" @@ -71,16 +72,7 @@ qemuBackupPrepare(virDomainBackupDef *def) switch (def->server->transport) { case VIR_STORAGE_NET_HOST_TRANS_TCP: - /* TODO: Update qemu.conf to provide a port range, - * probably starting at 10809, for obtaining automatic - * port via virPortAllocatorAcquire, as well as store - * somewhere if we need to call virPortAllocatorRelease - * during BackupEnd. Until then, user must provide port */ - if (!def->server->port) { - virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s", - _("<domainbackup> must specify TCP port for now")); - return -1; - } + /* port is auto-allocated if not set */ break; case VIR_STORAGE_NET_HOST_TRANS_UNIX: @@ -841,6 +833,16 @@ qemuBackupBegin(virDomainObj *vm, if (qemuBackupPrepare(def) < 0) goto endjob; + if (pull && def->server && + def->server->transport == VIR_STORAGE_NET_HOST_TRANS_TCP && + !def->server->port) { + unsigned short port = 0; + if (virPortAllocatorAcquire(priv->driver->backupPorts, &port) < 0) + goto endjob; + def->server->port = port; + priv->backupNBDPort = port; + } + if (qemuBackupBeginPrepareTLS(vm, cfg, def, &tlsProps, &tlsSecretProps) < 0) goto endjob; @@ -969,6 +971,11 @@ qemuBackupBegin(virDomainObj *vm, qemuDomainObjExitMonitor(vm); } + if (ret < 0 && priv->backupNBDPort) { + virPortAllocatorRelease(priv->backupNBDPort); + priv->backupNBDPort = 0; + } + if (ret < 0 && !job_started && priv->backup) def = g_steal_pointer(&priv->backup); @@ -1026,6 +1033,12 @@ qemuBackupNotifyBlockjobEndStopNBD(virDomainObj *vm, qemuDomainObjExitMonitor(vm); backup->nbdStopped = true; + + if (priv->backupNBDPort) { + virPortAllocatorRelease(priv->backupNBDPort); + priv->backupNBDPort = 0; + backup->server->port = 0; + } } diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c index de6e51177a..99e6a29148 100644 --- a/src/qemu/qemu_conf.c +++ b/src/qemu/qemu_conf.c @@ -74,6 +74,9 @@ VIR_LOG_INIT("qemu.qemu_conf"); #define QEMU_MIGRATION_PORT_MIN 49152 #define QEMU_MIGRATION_PORT_MAX 49215 +#define QEMU_BACKUP_PORT_MIN 10809 +#define QEMU_BACKUP_PORT_MAX 10872 + VIR_ENUM_IMPL(virQEMUSchedCore, QEMU_SCHED_CORE_LAST, "none", @@ -265,6 +268,9 @@ virQEMUDriverConfig *virQEMUDriverConfigNew(bool privileged, cfg->migrationPortMin = QEMU_MIGRATION_PORT_MIN; cfg->migrationPortMax = QEMU_MIGRATION_PORT_MAX; + cfg->backupPortMin = QEMU_BACKUP_PORT_MIN; + cfg->backupPortMax = QEMU_BACKUP_PORT_MAX; + /* For privileged driver, try and find hugetlbfs mounts automatically. * Non-privileged driver requires admin to create a dir for the * user, chown it, and then let user configure it manually. */ @@ -985,6 +991,25 @@ virQEMUDriverConfigLoadNetworkEntry(virQEMUDriverConfig *cfg, return -1; } + if (virConfGetValueUInt(conf, "backup_port_min", &cfg->backupPortMin) < 0) + return -1; + if (cfg->backupPortMin <= 0) { + virReportError(VIR_ERR_INTERNAL_ERROR, + _("%1$s: backup_port_min: port must be greater than 0"), + filename); + return -1; + } + + if (virConfGetValueUInt(conf, "backup_port_max", &cfg->backupPortMax) < 0) + return -1; + if (cfg->backupPortMax > 65535 || + cfg->backupPortMax < cfg->backupPortMin) { + virReportError(VIR_ERR_INTERNAL_ERROR, + _("%1$s: backup_port_max: port must be between the minimal port %2$d and 65535"), + filename, cfg->backupPortMin); + return -1; + } + if (virConfGetValueString(conf, "migration_host", &cfg->migrateHost) < 0) return -1; virStringStripIPv6Brackets(cfg->migrateHost); diff --git a/src/qemu/qemu_conf.h b/src/qemu/qemu_conf.h index c284e108a1..2e68f1de14 100644 --- a/src/qemu/qemu_conf.h +++ b/src/qemu/qemu_conf.h @@ -240,6 +240,9 @@ struct _virQEMUDriverConfig { unsigned int migrationPortMin; unsigned int migrationPortMax; + unsigned int backupPortMin; + unsigned int backupPortMax; + bool logTimestamp; bool stdioLogD; @@ -338,6 +341,9 @@ struct _virQEMUDriver { /* Immutable pointer, immutable object */ virPortAllocatorRange *migrationPorts; + /* Immutable pointer, immutable object */ + virPortAllocatorRange *backupPorts; + /* Immutable pointer, lockless APIs */ virSysinfoDef *hostsysinfo; diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h index 5755d2adb0..1153d8c6e0 100644 --- a/src/qemu/qemu_domain.h +++ b/src/qemu/qemu_domain.h @@ -147,6 +147,7 @@ struct _qemuDomainObjPrivate { char *origname; int nbdPort; /* Port used for migration with NBD */ unsigned short migrationPort; + unsigned short backupNBDPort; int preMigrationState; unsigned long long preMigrationMemlock; /* Original RLIMIT_MEMLOCK in case it was changed for the current diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index c5eedeedfa..a8034b4f26 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -714,6 +714,12 @@ qemuStateInitialize(bool privileged, cfg->migrationPortMax)) == NULL) goto error; + if ((qemu_driver->backupPorts = + virPortAllocatorRangeNew(_("backup"), + cfg->backupPortMin, + cfg->backupPortMax)) == NULL) + goto error; + if (qemuSecurityInit(qemu_driver) < 0) goto error; diff --git a/src/qemu/test_libvirtd_qemu.aug.in b/src/qemu/test_libvirtd_qemu.aug.in index 82cfec3b4b..2582c6a09c 100644 --- a/src/qemu/test_libvirtd_qemu.aug.in +++ b/src/qemu/test_libvirtd_qemu.aug.in @@ -110,6 +110,8 @@ module Test_libvirtd_qemu = { "migration_host" = "host.example.com" } { "migration_port_min" = "49152" } { "migration_port_max" = "49215" } +{ "backup_port_min" = "10809" } +{ "backup_port_max" = "10872" } { "log_timestamp" = "0" } { "nvram" { "1" = "/usr/share/OVMF/OVMF_CODE.fd:/usr/share/OVMF/OVMF_VARS.fd" } -- 2.52.0

2 1

[PATCH 0/4] libvirt: AMD IOMMU fixes
by Xiaotian Feng 13 Mar '26

13 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 13 Mar '26

13 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 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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[PATCH v7 0/2] qemu: Support accelerated vSMMUs
by Nathan Chen 11 Mar '26

11 Mar '26

Hi, This is a follow up to the sixth RFC patchset [0] for supporting multiple accelerated vSMMU instances. Support for user-creatable accelerated SMMUv3 in QEMU has been applied to target-arm.next [1]. For instance, specifying hostdevs associated with multiple accelerated SMMUs, configured to be routed to pcie-expander-bus controllers in a way where VFIO device to SMMUv3 associations are matched with the host: <devices> ... <controller type='pci' index='1' model='pcie-expander-bus'> <model name='pxb-pcie'/> <target busNr='252'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x0'/> </controller> <controller type='pci' index='2' model='pcie-expander-bus'> <model name='pxb-pcie'/> <target busNr='248'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/> </controller> ... <controller type='pci' index='21' model='pcie-root-port'> <model name='pcie-root-port'/> <target chassis='21' port='0x0'/> <address type='pci' domain='0x0000' bus='0x01' slot='0x00' function='0x0'/> </controller> <controller type='pci' index='22' model='pcie-root-port'> <model name='pcie-root-port'/> <target chassis='22' port='0xa8'/> <address type='pci' domain='0x0000' bus='0x02' slot='0x00' function='0x0'/> </controller> ... <hostdev mode='subsystem' type='pci' managed='no'> <source> <address domain='0x0009' bus='0x01' slot='0x00' function='0x0'/> </source> <vpasidCapOffset>0xff8</vpasidCapOffset> <address type='pci' domain='0x0000' bus='0x15' slot='0x00' function='0x0'/> </hostdev> <hostdev mode='subsystem' type='pci' managed='no'> <source> <address domain='0x0019' bus='0x01' slot='0x00' function='0x0'/> </source> <vpasidCapOffset>0xff8</vpasidCapOffset> <address type='pci' domain='0x0000' bus='0x16' slot='0x00' function='0x0'/> </hostdev> <iommu model='smmuv3'> <driver parentIdx='1' accel='on' ats='on' ril='off' ssidSize='20' oas='44'/> </iommu> <iommu model='smmuv3'> <driver parentIdx='2' accel='on' ats='on' ril='off' ssidSize='20' oas='44'/> </iommu> </devices> This would get translated to a qemu command line with the arguments below: -device '{"driver":"pxb-pcie","bus_nr":252,"id":"pci.1","bus":"pcie.0","addr":"0x1"}' \ -device '{"driver":"pxb-pcie","bus_nr":248,"id":"pci.2","bus":"pcie.0","addr":"0x2"}' \ -device '{"driver":"pcie-root-port","port":0,"chassis":21,"id":"pci.21","bus":"pci.1","addr":"0x0"}' \ -device '{"driver":"pcie-root-port","port":168,"chassis":22,"id":"pci.22","bus":"pci.2","addr":"0x0"}' \ -device '{"driver":"arm-smmuv3","primary-bus":"pci.1","id":"iommu0","accel":true,"ats":true,"ril":false,"ssidsize":20,"oas":44}' \ -device '{"driver":"arm-smmuv3","primary-bus":"pci.2","id":"iommu1","accel":true,"ats":true,"ril":false,"ssidsize":20,"oas":44}' \ -device '{"driver":"vfio-pci","host":"0009:01:00.0","id":"hostdev0","x-vpasid-cap-offset":4088,"bus":"pci.21","addr":"0x0"}' \ -device '{"driver":"vfio-pci","host":"0019:01:00.0","id":"hostdev1","x-vpasid-cap-offset":4088,"bus":"pci.22","addr":"0x0"}' \ This series is on Github: https://github.com/NathanChenNVIDIA/libvirt/tree/smmuv3-accel-01-26-v7/ Thanks, Nathan Changes from v6: - Remove smmuv3 'pasid' attribute - Add smmuv3 'ssidsize' attribute - Add support for 'vpasidCapOffset' element - Modify logic for building accel smmuv3 qemu command line to omit ATS, RIL, accel flags when not needed (enabled/disabled by default in QEMU SMMUv3) [0] https://lists.libvirt.org/archives/list/devel@lists.libvirt.org/thread/VRSS… [1] https://lore.kernel.org/qemu-devel/20260126104342.253965-1-skolothumtho@nvi… Nathan Chen (2): qemu: Add support for HW-accelerated nested SMMUv3 tests: qemuxmlconfdata: provide HW-accel smmuv3 sample XML and CLI args docs/formatdomain.rst | 36 +++++++ src/conf/domain_conf.c | 101 +++++++++++++++++- src/conf/domain_conf.h | 6 ++ src/conf/domain_validate.c | 36 ++++++- src/conf/schemas/domaincommon.rng | 32 ++++++ src/qemu/qemu_command.c | 23 ++++ src/util/virpci.h | 4 + ...u-smmuv3-pci-bus-accel.aarch64-latest.args | 38 +++++++ ...mu-smmuv3-pci-bus-accel.aarch64-latest.xml | 64 +++++++++++ .../iommu-smmuv3-pci-bus-accel.xml | 54 ++++++++++ tests/qemuxmlconftest.c | 1 + 11 files changed, 390 insertions(+), 5 deletions(-) create mode 100644 tests/qemuxmlconfdata/iommu-smmuv3-pci-bus-accel.aarch64-latest.args create mode 100644 tests/qemuxmlconfdata/iommu-smmuv3-pci-bus-accel.aarch64-latest.xml create mode 100644 tests/qemuxmlconfdata/iommu-smmuv3-pci-bus-accel.xml -- 2.43.0

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