August 2026 - Devel - libvirt List Archives

[PATCH] esx: Don't crash when parsing unmounted datastore
by Michal Privoznik 18 Aug '26

18 Aug '26

From: Michal Privoznik <mprivozn(a)redhat.com> When parsing disk source in ESX driver (esxParseVMXFileName()) the datastore is traversed through trying to find matching prefix. But not every datastore has to be mounted. In that case, esxVI_LookupDatastoreHostMount() returns success and the returned struct has mountInfo->path set to NULL. This can be deducted from the following backtrace (which shows that strlen() hidden in STRSKIP() macro was given NULL pointer). Thread 1 "virsh" received signal SIGSEGV, Segmentation fault. __strlen_avx2 () at ../sysdeps/x86_64/multiarch/strlen-avx2.S:76 76 VPCMPEQ (%rdi), %ymm0, %ymm1 (gdb) bt full #0 __strlen_avx2 () at ../sysdeps/x86_64/multiarch/strlen-avx2.S:76 No locals. #1 0x00007ffff7c292d7 in esxParseVMXFileName (fileName=0x5555557341d0 "/vmfs/volumes/5f64209f-c0af0aa8-70c4-e4434ba73190/msafra-RHEL9-shared-1/msafra-RHEL9-shared-1_1.vmdk", opaque=0x7fffffffcf80, out=0x7fffffffc738, allow_missing=false) at ../src/esx/esx_driver.c:172 data = 0x7fffffffcf80 propertyNameList = 0x555555738b50 datastoreList = 0x55555573cf40 datastore = <optimized out> hostMount = 0x555555733640 datastoreName = 0x55555573e590 "mnecas-nfs-test" tmp = <optimized out> saveptr = 0x5555556a5b50 "" strippedFileName = 0x0 copyOfFileName = 0x0 directoryAndFileName = <optimized out> ret = -1 __FUNCTION__ = "esxParseVMXFileName" #2 0x00007ffff7bd47f4 in virVMXParseDisk (ctx=ctx@entry=0x7fffffffcfb0, xmlopt=xmlopt@entry=0x555555738d80, conf=conf@entry=0x5555556a5b50, device=device@entry=0, busType=<optimized out>, busType@entry=3, controllerOrBus=controllerOrBus@entry=1, unit=<optimized out>, def=0x7fffffffc960, vmdef=0x5555557375a0) at ../src/vmx/vmx.c:2553 tmp = 0x0 result = -1 prefix = 0x5555557384d0 "scsi1:0" present_name = "scsi1:0.present", '\000' <repeats 16 times> present = true startConnected_name = "scsi1:0.startConnected\000\000\000\000\000\000\000\000\000" startConnected = true deviceType_name = "scsi1:0.deviceType", '\000' <repeats 13 times> deviceType = 0x555555737f60 "scsi-hardDisk" clientDevice_name = "scsi1:0.clientDevice", '\000' <repeats 11 times> clientDevice = false fileType_name = "scsi1:0.fileType", '\000' <repeats 15 times> fileType = 0x0 fileName_name = "scsi1:0.fileName", '\000' <repeats 15 times> fileName = 0x5555557341d0 "/vmfs/volumes/5f64209f-c0af0aa8-70c4-e4434ba73190/msafra-RHEL9-shared-1/msafra-RHEL9-shared-1_1.vmdk" writeThrough_name = "scsi1:0.writeThrough", '\000' <repeats 11 times> writeThrough = false mode_name = "scsi1:0.mode", '\000' <repeats 19 times> mode = 0x0 cleanup = <optimized out> __FUNCTION__ = "virVMXParseDisk" #3 0x00007ffff7bd5f01 in virVMXParseConfig (ctx=0x7fffffffcfb0, xmlopt=0x555555738d80, caps=<optimized out>, vmx=<optimized out>) at ../src/vmx/vmx.c:1749 #4 0x00007ffff7c35319 in esxDomainGetXMLDesc (domain=<optimized out>, flags=0) at ../src/esx/esx_driver.c:2595 #5 0x00007ffff7cc4fd3 in virDomainGetXMLDesc (domain=domain@entry=0x5555557367f0, flags=flags@entry=0) at ../src/libvirt-domain.c:2898 #6 0x0000555555586cca in cmdDumpXML (ctl=0x7fffffffd1d0, cmd=0x5555556a5450) at ../tools/virsh-domain.c:10787 #7 0x00005555555bc7cb in vshCommandRun (ctl=0x7fffffffd1d0, cmd=0x5555556a5450) at ../tools/vsh.c:1383 #8 0x0000555555562fbc in main (argc=<optimized out>, argv=0x7fffffffd5c8) at ../tools/virsh.c:900 The backtrace was trimmed. To fix this, just check whether mount path is not NULL before passing it to STRSKIP(). Resolves: https://redhat.atlassian.net/browse/RHEL-213506 Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com> --- BTW: this crasher is easily reproducible with our test suite too. Just comment line 49 in tests/vmx2xmlmock.c file and run vmx2xmltest. src/esx/esx_driver.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/src/esx/esx_driver.c b/src/esx/esx_driver.c index c5b3fa47b6..75bbd07750 100644 --- a/src/esx/esx_driver.c +++ b/src/esx/esx_driver.c @@ -169,6 +169,9 @@ esxParseVMXFileName(const char *fileName, goto cleanup; } + if (!hostMount->mountInfo->path) + continue; + tmp = (char *)STRSKIP(fileName, hostMount->mountInfo->path); if (!tmp) -- 2.54.0

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[PATCH v2 0/5] qemu: auto-select win-dmp for Windows guest crash dumps
by Denis V. Lunev 18 Aug '26

18 Aug '26

Auto-triggered dumps (on_crash, watchdog) always use QEMU's elf default, which is not WinDbg-loadable for a Windows guest and cannot be reliably converted after the fact. This was proposed before as a per-domain XML knob (https://www.mail-archive.com/devel@lists.libvirt.org/msg09638.html) Daniel P. Berrange objected: QEMU's query-dump-guest-memory-capability reported win-dmp as available on any x86-64 guest regardless of whether it had actually published a Windows dump header, so trusting it was not safe. QEMU's win_dump_available() has since been fixed to check the guest's vmcoreinfo note (https://lore.kernel.org/qemu-devel/20260619101834.228432-1-den@openvz.org/, commit b4bdad7dce). Validated against real guests: a Windows Server 2022 guest crashed via Sysinternals NotMyFault produces a PAGEDU64 (win-dmp) dump; an AlmaLinux 9 guest crashed via sysrq produces an ELF one. A 1GiB quota across two Linux crashes pruned the older dump and kept the newer, over-quota one. syntax-check and virstringtest pass. Changes since v1: * detect the 'allowed-by-guest' feature QEMU 11.1 puts on the win-dmp member of DumpGuestMemoryFormat (thanks Daniel for idea) * skip the probe unless that capability is present, so QEMU that offers win-dmp to every x86 guest keeps the elf default (Daniel). * fix the sort position of both new symbols in libvirt_private.syms, which v1 got wrong; picked up Daniel's Reviewed-by. * update virtlogd.aug and test_virtlogd.aug.in for the quoted form (Daniel). * update libvirtd_qemu.aug and test_libvirtd_qemu.aug.in for the new setting, and VIR_INFO -> VIR_DEBUG (both Daniel); count and remove only the dumps libvirt itself wrote, and skip pruning after a failed dump. * renamed test helpers for virStrToBytes * NEWS.rst entries added. Denis V. Lunev (5): qemu: add capability for guest-aware win-dmp availability qemu: auto-select win-dmp for crash- and watchdog-triggered dumps util: add virStrToBytes() and virConfGetValueBytes() for scaled sizes logging: accept a unit suffix in virtlogd's max_size qemu: cap total size of auto-triggered dumps under auto_dump_path NEWS.rst | 19 ++ src/libvirt_private.syms | 2 + src/logging/log_daemon_config.c | 2 +- src/logging/log_daemon_config.h | 2 +- src/logging/test_virtlogd.aug.in | 2 +- src/logging/virtlogd.aug | 5 +- src/logging/virtlogd.conf | 7 +- src/qemu/libvirtd_qemu.aug | 4 + src/qemu/qemu.conf.in | 17 ++ src/qemu/qemu_capabilities.c | 4 + src/qemu/qemu_capabilities.h | 3 + src/qemu/qemu_conf.c | 2 + src/qemu/qemu_conf.h | 1 + src/qemu/qemu_driver.c | 163 +++++++++++++++++- src/qemu/test_libvirtd_qemu.aug.in | 1 + src/util/virconf.c | 47 +++++ src/util/virconf.h | 3 + src/util/virutil.c | 23 +++ src/util/virutil.h | 5 + .../caps_11.1.0_aarch64.replies | 5 +- .../caps_11.1.0_aarch64.xml | 1 + .../caps_11.1.0_x86_64.replies | 5 +- .../caps_11.1.0_x86_64.xml | 1 + tests/qemumonitorjsontest.c | 3 + tests/virstringtest.c | 76 ++++++++ 25 files changed, 394 insertions(+), 9 deletions(-) -- 2.53.0

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[PATCH v3 0/3] qemu: Support vCMDQ
by Nathan Chen 18 Aug '26

18 Aug '26

Hi, This is a follow up to the previous RFC patchset [0] for supporting Tegra241 vCMDQ. This patchset is tested with Shameer's qemu series for vCMDQ support. The accelerated SMMUv3 series for qemu and Libvirt are pre-requisites for vCMDQ support, as accelerated SMMUv3 must be enabled alongside vCMDQ. A new 'cmdqv' <iommu> driver attribute is introduced to toggle enabling vCMDQ support. For instance, specifying hostdevs associated with multiple accelerated SMMUs + CMDQV enabled, 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> <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> <address type='pci' domain='0x0000' bus='0x16' slot='0x00' function='0x0'/> </hostdev> <iommu model='smmuv3'> <driver pciBus='1' accel='on' ats='on' ril='on' ssidsize='20' oas='44' cmdqv='on'/> </iommu> <iommu model='smmuv3'> <driver pciBus='2' accel='on' ats='on' ril='on' ssidsize='20' oas='44' cmdqv='on'/> </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,"cmdqv":"on","ril":true,"pasid":true,"oas":44}' \ -device '{"driver":"arm-smmuv3","primary-bus":"pci.2","id":"iommu1","accel":true,"ats":true,"cmdqv":"on","ril":true,"pasid":true,"oas":44}' \ -device '{"driver":"vfio-pci","host":"0009:01:00.0","id":"hostdev0","bus":"pci.21","addr":"0x0"}' \ -device '{"driver":"vfio-pci","host":"0019:01:00.0","id":"hostdev1","bus":"pci.22","addr":"0x0"}' \ This series is on Github: https://github.com/NathanChenNVIDIA/libvirt/tree/cmdqv-v3/ Thanks, Nathan Changes from v2: - Add QEMU capabilities support for cmdqv - Change QEMU command line parameter to expect OnOffAuto string Changes from v1: - Remove 'identifier' attribute for SMMUv3 - Change QEMU command line property from 'tegra241-cmdqv' to 'cmdqv' - Support QEMU OnOffAuto CMDQV property instead of expecting a bool [0] https://lists.libvirt.org/archives/list/devel@lists.libvirt.org/thread/CE6U… Nathan Chen (3): qemu: introduce QEMU_CAPS_ARM_SMMUV3_CMDQV qemu: add IOMMU attribute "cmdqv" for smmuv3 tests: qemuxmlconfdata: provide cmdqv sample XML and CLI args docs/formatdomain.rst | 6 ++ src/conf/domain_conf.c | 15 +++++ src/conf/domain_conf.h | 1 + src/conf/domain_validate.c | 6 +- src/conf/schemas/domaincommon.rng | 5 ++ src/qemu/qemu_capabilities.c | 4 ++ src/qemu/qemu_capabilities.h | 3 + src/qemu/qemu_command.c | 1 + src/qemu/qemu_validate.c | 8 +++ .../caps_11.1.0_aarch64.xml | 1 + ...v3-pci-bus-accel-cmdqv.aarch64-latest.args | 40 +++++++++++++ ...uv3-pci-bus-accel-cmdqv.aarch64-latest.xml | 59 +++++++++++++++++++ .../iommu-smmuv3-pci-bus-accel-cmdqv.xml | 49 +++++++++++++++ tests/qemuxmlconftest.c | 1 + 14 files changed, 198 insertions(+), 1 deletion(-) create mode 100644 tests/qemuxmlconfdata/iommu-smmuv3-pci-bus-accel-cmdqv.aarch64-latest.args create mode 100644 tests/qemuxmlconfdata/iommu-smmuv3-pci-bus-accel-cmdqv.aarch64-latest.xml create mode 100644 tests/qemuxmlconfdata/iommu-smmuv3-pci-bus-accel-cmdqv.xml -- 2.43.0

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[PATCH] qemu: Fix proper ordering of 'virtlockd' shutdown
by Peter Krempa 18 Aug '26

18 Aug '26

From: Peter Krempa <pkrempa(a)redhat.com> In commit aa1bf13b9caa4ef893cd4fdbaa111d5da73aa120 I attempted to fix the ordering of virtlockd and virtlogd during shutdown but I made a typo in the name of 'virtlockd.service' (missing 'd'). Fixes: aa1bf13b9caa4ef893cd4fdbaa111d5da73aa120 Signed-off-by: Peter Krempa <pkrempa(a)redhat.com> --- src/qemu/virtqemud.service.extra.in | 2 +- src/remote/libvirtd.service.in | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/src/qemu/virtqemud.service.extra.in b/src/qemu/virtqemud.service.extra.in index 3cc2edcfd0..df36890704 100644 --- a/src/qemu/virtqemud.service.extra.in +++ b/src/qemu/virtqemud.service.extra.in @@ -9,7 +9,7 @@ After=virtlockd.socket # To ensure that our helper daemons are not shut down before the main daemon # shuts down we need also explicit ordering with the .service unit After=virtlogd.service -After=virtlock.service +After=virtlockd.service Wants=systemd-machined.service After=systemd-machined.service After=remote-fs.target diff --git a/src/remote/libvirtd.service.in b/src/remote/libvirtd.service.in index f26494d646..ccdb8379f3 100644 --- a/src/remote/libvirtd.service.in +++ b/src/remote/libvirtd.service.in @@ -18,7 +18,7 @@ After=virtlockd.socket # To ensure that our helper daemons are not shut down before the main daemon # shuts down we need also explicit ordering with the .service unit After=virtlogd.service -After=virtlock.service +After=virtlockd.service Wants=systemd-machined.service After=network.target After=dbus.service -- 2.55.0

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[PATCH 0/6] conf: add vlen tag for RISC-V CPUs
by Heinrich Schuchardt 18 Aug '26

18 Aug '26

RISC-V CPUs may provide a scalable vector extension. The length of the vector registers is implementation specific. QEMU allows to set the vector length as a CPU property, e.g. '-cpu rva23s64,vlen=256'. To describe this feature a new CPU tag is introduced: <vlen value='N'> According to the RISC-V ISA specification vlen must be a power of 2 in the range 8 to 65536. A configuration test is provided. Heinrich Schuchardt (6): conf: add vlen tag for RISC-V CPUs schemas: add cpuVlen definition for RISC-V vector length qemu: validate that CPU vlen is only used with RISC-V qemu: emit vlen= CPU property on the command line tests: provide vlen configuration test docs: add vlen to formatdomain documentation docs/formatdomain.rst | 13 ++++++++ src/conf/cpu_conf.c | 25 +++++++++++++++ src/conf/cpu_conf.h | 1 + src/conf/schemas/cputypes.rng | 11 +++++++ src/qemu/qemu_command.c | 3 ++ src/qemu/qemu_validate.c | 9 ++++++ .../riscv64-virt-vlen.riscv64-latest.args | 31 +++++++++++++++++++ .../riscv64-virt-vlen.riscv64-latest.xml | 26 ++++++++++++++++ tests/qemuxmlconfdata/riscv64-virt-vlen.xml | 26 ++++++++++++++++ tests/qemuxmlconftest.c | 2 ++ 10 files changed, 147 insertions(+) create mode 100644 tests/qemuxmlconfdata/riscv64-virt-vlen.riscv64-latest.args create mode 100644 tests/qemuxmlconfdata/riscv64-virt-vlen.riscv64-latest.xml create mode 100644 tests/qemuxmlconfdata/riscv64-virt-vlen.xml -- 2.53.0

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[PATCH v3 0/7] Add TLS-PSK support for migration
by Abhisek Panda 17 Aug '26

17 Aug '26

QEMU provides the capability to encrypt the migration data stream using two transport layer security (TLS) authentication schemes: X.509 certificates and pre-shared keys (PSK). Currently, Libvirt only supports the X.509-based TLS authentication scheme. In TLS X.509 certificates, a set of live migrations utilize a fixed set of static certificates for encrypted migration. In this authentication scheme, users require to deploy a certificate authority and monitor the certificate expiration window. In case certificates are compromised all the future live migrations are vulnerable. To resolve this, this patch series introduce the support for pre-shared key-based authentication scheme. This mechanism relies on symmetric pre-shared keys (a secret key that is known to both sender and receiver prior to secure communication) for providing secure transfer of data. Libvirt solely manages the lifecycle of the ephemeral pre-shared keys, including, generation, persistent storage, and cleanup. Libvirt generates the key on the source machine, then transfers it to the destination machine using the migration cookie. To allow users to configure the size of the key, Libvirt provides the migrate_tls_psk_length configuration parameter in qemu.conf. To avoid introduction of an additional VIR_MIGRATE_* flag, we rely on existing the VIR_MIGRATE_TLS flag. If the VIR_MIGRATE_TLS flag is set but the necessary X.509 credential files are missing on the destination, then we fallback to using PSK-based authentication scheme during migration. v3: 1. Destination host decides which TLS authentication scheme to use. 2. The directory of the key file is set to <tls_psk_state_dir>/$ID-$VMNAME. 3. Use the same alias for both tls-creds-x509 and tls-creds-psk objects. 4. Validate the length of the pre-shared key. 5. Unit test to validate the pre-shared key in the migration cookie. v2: 1. Libvirt manages the lifecycle of pre-shared keys. 2. Transfer of keys to the destination via the migration cookie 3. Remove the VIR_MIGRATE_TLS_PSK flag instead rely on VIR_MIGRATE_TLS and availability of ca-cert.pem on source. 4. Drop VIR_MIGRATE_PARAM_TLS_PSK_DIRECTORY, Libvirt solely manages the pre-shared keys. Abhisek Panda (7): conf: Add a configuration param for TLS-PSK qemu: Manage a pre-shared key's lifecycle qemu: Add support to build the tls-creds-psk object qemu: rename tls-creds-x509 obj related functions qemu: Manage tls-creds-psk object lifecycle qemu: Set up the migrate TLS-PSK objects tests: Add testing of pre-shared key lifecycle include/libvirt/libvirt-domain.h | 11 +- src/qemu/libvirtd_qemu.aug | 1 + src/qemu/qemu.conf.in | 8 ++ src/qemu/qemu_command.c | 26 ++++ src/qemu/qemu_command.h | 7 + src/qemu/qemu_conf.c | 22 ++++ src/qemu/qemu_conf.h | 2 + src/qemu/qemu_domain.c | 1 + src/qemu/qemu_domain.h | 1 + src/qemu/qemu_driver.c | 6 + src/qemu/qemu_hotplug.c | 40 +++--- src/qemu/qemu_hotplug.h | 24 ++-- src/qemu/qemu_migration.c | 202 +++++++++++++++++++++++++---- src/qemu/qemu_migration_cookie.c | 94 +++++++++++++- src/qemu/qemu_migration_cookie.h | 5 + src/qemu/qemu_migration_params.c | 98 +++++++++++--- src/qemu/qemu_migration_params.h | 22 +++- src/qemu/test_libvirtd_qemu.aug.in | 1 + tests/qemumigrationcookiexmltest.c | 141 +++++++++++++++++++- tests/testutilsqemu.c | 12 ++ 20 files changed, 631 insertions(+), 93 deletions(-) -- 2.43.7

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[PATCH 0/5] Add guest device info to virDomainGetGuestInfo
by Michal Privoznik 17 Aug '26

17 Aug '26

*** BLURB HERE *** Michal Prívozník (5): Add guest device info to virDomainGetGuestInfo qemu_agent: Introduce guest-get-info qemuagenttest: Introduce GetGuestDeviceInfo test case qemu: Implement device info for virDomainGetGuestInfo() API virsh: Add support for VIR_DOMAIN_GUEST_INFO_DEVICES docs/manpages/virsh.rst | 17 ++++- include/libvirt/libvirt-domain.h | 78 ++++++++++++++++++++ src/hypervisor/qemu_agent.c | 119 ++++++++++++++++++++++++++++++ src/hypervisor/qemu_agent.h | 21 ++++++ src/libvirt-domain.c | 5 ++ src/libvirt_private.syms | 2 + src/qemu/qemu_driver.c | 58 ++++++++++++++- tests/qemuagenttest.c | 123 +++++++++++++++++++++++++++++++ tools/virsh-domain.c | 6 ++ 9 files changed, 424 insertions(+), 5 deletions(-) -- 2.54.0

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[PATCH v2 0/6] Add guest device info to virDomainGetGuestInfo
by Michal Privoznik 15 Aug '26

15 Aug '26

Rebased and slightly amended version of: https://lists.libvirt.org/archives/list/devel@lists.libvirt.org/thread/6V6K… diff to v1: - Rebase, because the original series no longer applies cleanly - Implement the device info for the bhyve driver too Michal Prívozník (6): Add guest device info to virDomainGetGuestInfo qemu_agent: Introduce guest-get-info qemuagenttest: Introduce GetGuestDeviceInfo test case qemu: Implement device info for virDomainGetGuestInfo() API bhyve: Implement device info for virDomainGetGuestInfo() API virsh: Add support for VIR_DOMAIN_GUEST_INFO_DEVICES docs/manpages/virsh.rst | 17 +++- include/libvirt/libvirt-domain.h | 78 ++++++++++++++++ src/bhyve/bhyve_driver.c | 21 ++++- src/hypervisor/qemu_agent.c | 155 +++++++++++++++++++++++++++++++ src/hypervisor/qemu_agent.h | 26 ++++++ src/libvirt-domain.c | 5 + src/libvirt_private.syms | 3 + src/qemu/qemu_driver.c | 21 ++++- tests/qemuagenttest.c | 123 ++++++++++++++++++++++++ tools/virsh-domain.c | 6 ++ 10 files changed, 449 insertions(+), 6 deletions(-) -- 2.54.0

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[PATCH 0/2] qemu: Fix detach of a CD-ROM device with no media
by Mitsuru Kariya 14 Aug '26

14 Aug '26

Detaching a CD-ROM device that has no media inserted currently logs an internal error: internal error: unable to execute QEMU command 'blockdev-del': Failed to find node with node-name='libvirt-N-storage' or, when no stale node name is present in the source: internal error: argument key 'node-name' must not have null value The root cause is that an empty disk source (path == NULL) satisfies virStorageSourceIsBacking() while no corresponding blockdev node ever exists in QEMU, so the detach path prepares a blockdev-del for a node that was never created. Patch 1 fixes the detach path itself: qemuDomainRemoveDiskDevice() now skips the blockdev detach preparation for an empty source, mirroring what the old-media detach in qemuDomainChangeMediaBlockdev() already does. Patch 2 fixes the way the stale node name gets there in the first place: qemuDomainChangeEjectableMedia() ran the full image setup (qemuDomainPrepareDiskSource(), backing chain detection, storage access, managed PR) even when ejecting to no media, assigning node names to an empty source that are never realized in QEMU. The setup is now skipped for an empty source, mirroring qemuDomainAttachDeviceDiskLiveInternal(), and rollback only revokes storage access when it was actually granted. To reproduce the 1st message: 1. Start a domain with a CD-ROM device with media attached 2. virsh change-media $dom $target --eject --live 3. virsh detach-disk $dom $target --live To reproduce the 2nd message: 1. Start a domain with a CD-ROM device without media attached 2. virsh detach-disk $dom $target --live No regression tests are added. Neither failure mode is reachable from qemuhotplugtest: the "null value" variant fails while constructing the blockdev-del arguments, before any QMP command is sent, leaving nothing for the test monitor to observe; the stale-node-name variant does emit a blockdev-del and would be detectable, but requires a preceding media eject to set up, which qemuhotplugtest cannot drive. Mitsuru Kariya (2): qemu: Skip empty disk source when detaching a disk device qemu: Don't prepare an empty disk source on media change src/qemu/qemu_hotplug.c | 27 +++++++++++++++++---------- 1 file changed, 17 insertions(+), 10 deletions(-) base-commit: 674fcf87bdd479302032fbeb331fea2aa51606ac -- 2.43.0

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[PATCH 0/2] storage_file: Fix probing of backing images with 'data_file' with auto-probed format
by Peter Krempa 14 Aug '26

14 Aug '26

Patch 1 adds an counter-example test and patch 2 then fixes the bug. Peter Krempa (2): virstoragetest: Add example of a qcow2 image with a backing image pointing to a data_file without 'backing_format' virStorageSourceGetMetadataRecurse: Fix format probing exception for images with 'data_file' src/storage_file/storage_source.c | 3 ++- tests/virstoragetest.c | 7 ++++++- .../images/qcow2_datafile-auto.qcow2 | Bin 0 -> 196616 bytes 3 files changed, 8 insertions(+), 2 deletions(-) create mode 100644 tests/virstoragetestdata/images/qcow2_datafile-auto.qcow2 -- 2.55.0

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