July 2026 - Devel - libvirt List Archives

[PATCH] src: fix crash searching for XML context string on errors
by Daniel P. Berrangé 15 Jul '26

15 Jul '26

From: Daniel P. Berrangé <berrange(a)redhat.com> When we have an XML parse error, libxml2 invokes a callback that receives pointers to the start of the document being parsed and the location where the error was triggered. In the case of a document that contains 100's of empty lines (ie a sequence of newlines), at some point libxml2 will advance the base pointer discarding the useful context. Thus when catchXMLError then searches backwards to discard empty lines and look for the context element, it will eventually get to the start of the string. When this happens the virBuffer that holds the context string ends up empty and then catchXMLError will dereference a NULL pointer. In almost all cases, the APIs which accept XML documents from the user are behind the primary read-write socket, however, the CPU baseline API is exposed to the read-only socket. Thus an unprivileged user can trigger a denial of service by crashing the libvirt daemons with a malicious XML document. Check for this empty string condition and skip inclusion of the XML document context in the error message. Fixes: CVE-2026-61478 Reported-by: Rx <rx1513(a)altlinux.org> Signed-off-by: Daniel P. Berrangé <berrange(a)redhat.com> --- src/util/virxml.c | 46 +++++++++++++++++++++++++++++++--------------- 1 file changed, 31 insertions(+), 15 deletions(-) diff --git a/src/util/virxml.c b/src/util/virxml.c index beb5301378..8349115633 100644 --- a/src/util/virxml.c +++ b/src/util/virxml.c @@ -1173,7 +1173,8 @@ catchXMLError(void *ctx, const char *msg G_GNUC_UNUSED, ...) contextstr = virBufferContentAndReset(&buf); /* (leave buffer space for pointer + line terminator) */ - for (n = 0; (n<col) && (contextstr[n] != 0); n++) { + + for (n = 0; (n<col) && contextstr && contextstr[n]; n++) { if (contextstr[n] == '\t') virBufferAddChar(&buf, '\t'); else @@ -1184,21 +1185,36 @@ catchXMLError(void *ctx, const char *msg G_GNUC_UNUSED, ...) pointerstr = virBufferContentAndReset(&buf); - if (filename) { - virGenericReportError(domcode, VIR_ERR_XML_DETAIL, - _("%1$s:%2$d: %3$s%4$s\n%5$s"), - filename, - lastError->line, - lastError->message, - contextstr, - pointerstr); + if (contextstr) { + if (filename) { + virGenericReportError(domcode, VIR_ERR_XML_DETAIL, + _("%1$s:%2$d: %3$s%4$s\n%5$s"), + filename, + lastError->line, + lastError->message, + contextstr, + pointerstr); + } else { + virGenericReportError(domcode, VIR_ERR_XML_DETAIL, + _("at line %1$d: %2$s%3$s\n%4$s"), + lastError->line, + lastError->message, + contextstr, + pointerstr); + } } else { - virGenericReportError(domcode, VIR_ERR_XML_DETAIL, - _("at line %1$d: %2$s%3$s\n%4$s"), - lastError->line, - lastError->message, - contextstr, - pointerstr); + if (filename) { + virGenericReportError(domcode, VIR_ERR_XML_DETAIL, + _("%1$s:%2$d: %3$s"), + filename, + lastError->line, + lastError->message); + } else { + virGenericReportError(domcode, VIR_ERR_XML_DETAIL, + _("at line %1$d: %2$s"), + lastError->line, + lastError->message); + } } } -- 2.55.0

2 1

[PATCH] qemu: qemuDomainRenameCallback: tidy up
by Roman Bogorodskiy 14 Jul '26

14 Jul '26

A few non-functional changes improving overall readability: - Use g_steal_pointer() for domain name switch code. - Clean up the 'cleanup' handler. - Fix indent for virDomainEventLifecycleNewFromObj() arguments. Signed-off-by: Roman Bogorodskiy <bogorodskiy(a)gmail.com> --- src/qemu/qemu_driver.c | 26 ++++++++++++++------------ 1 file changed, 14 insertions(+), 12 deletions(-) diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index 3d57de389b..6c124672d4 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -19064,9 +19064,8 @@ qemuDomainRenameCallback(virDomainObj *vm, } /* Switch name in domain definition. */ - old_dom_name = vm->def->name; - vm->def->name = new_dom_name; - new_dom_name = NULL; + old_dom_name = g_steal_pointer(&vm->def->name); + vm->def->name = g_steal_pointer(&new_dom_name); if (virDomainSnapshotForEach(vm->snapshots, qemuDomainSnapshotWriteMetadataIter, @@ -19085,22 +19084,25 @@ qemuDomainRenameCallback(virDomainObj *vm, VIR_DOMAIN_EVENT_UNDEFINED, VIR_DOMAIN_EVENT_UNDEFINED_RENAMED); event_new = virDomainEventLifecycleNewFromObj(vm, - VIR_DOMAIN_EVENT_DEFINED, - VIR_DOMAIN_EVENT_DEFINED_RENAMED); + VIR_DOMAIN_EVENT_DEFINED, + VIR_DOMAIN_EVENT_DEFINED_RENAMED); virObjectEventStateQueue(driver->domainEventState, event_old); virObjectEventStateQueue(driver->domainEventState, event_new); ret = 0; cleanup: - if (old_dom_name && ret < 0) { - new_dom_name = vm->def->name; - vm->def->name = old_dom_name; - old_dom_name = NULL; - } + if (ret < 0) { + if (old_dom_name) { + new_dom_name = vm->def->name; + vm->def->name = old_dom_name; + old_dom_name = NULL; + } - if (ret < 0) virErrorPreserveLast(&err); - qemuDomainNamePathsCleanup(cfg, ret < 0 ? new_dom_name : old_dom_name, true); + qemuDomainNamePathsCleanup(cfg, new_dom_name, true); + } else { + qemuDomainNamePathsCleanup(cfg, old_dom_name, true); + } virErrorRestore(&err); return ret; } -- 2.52.0

2 1

[PATCH 0/3] bhyve: improve domain startup error handling
by Roman Bogorodskiy 13 Jul '26

13 Jul '26

Roman Bogorodskiy (3): bhyve: error handling for monitor opening bhyve: improve domain startup error handling bhyve: clear monitor reference on close src/bhyve/bhyve_driver.c | 2 +- src/bhyve/bhyve_monitor.c | 6 ++-- src/bhyve/bhyve_process.c | 73 ++++++++++++++++++++++++--------------- src/bhyve/bhyve_process.h | 3 +- 4 files changed, 51 insertions(+), 33 deletions(-) -- 2.52.0

2 6

[PATCH v18 03/14] net/tap: deprecate "no" as special value for script/downscript
by Vladimir Sementsov-Ogievskiy 13 Jul '26

13 Jul '26

The interface is ambiguous, as "no" is valid file name. So, using "no" as a special value to disable script is deprecated. Use an empty string ("script=" / "downscript=") instead. In a future version, "no" will be treated as a plain file name, just like any other non-empty value. Document the deprecation in docs/about/deprecated.rst, qapi/net.json, and qemu-options.hx. Update other docs to use empty string instead of "no". Add a warning. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov(a)yandex-team.ru> --- docs/about/deprecated.rst | 18 ++++++++++++++++++ docs/system/i386/microvm.rst | 4 ++-- docs/system/i386/xenpvh.rst | 2 +- docs/system/ppc/ppce500.rst | 4 ++-- docs/system/riscv/microchip-icicle-kit.rst | 2 +- docs/system/riscv/sifive_u.rst | 2 +- net/tap.c | 2 ++ qapi/net.json | 12 ++++++++---- qemu-options.hx | 7 +++++-- 9 files changed, 40 insertions(+), 13 deletions(-) diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst index 0c656a968fc..c4929317e3a 100644 --- a/docs/about/deprecated.rst +++ b/docs/about/deprecated.rst @@ -71,6 +71,15 @@ flexible enough. The monitor objects have been converted to QOM, so ``-mon mode=control`` is replaced by ``-object monitor-qmp``. The short convenience options are not deprecated, only ``-mon``. +``script=no`` and ``downscript=no`` for ``-netdev tap`` (since 11.2) +''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' + +The special value ``"no"`` for the ``script`` and ``downscript`` +parameters of ``-netdev tap`` disables script execution. This special +treatment of ``"no"`` is deprecated. Use an empty string (``script=`` +or ``downscript=``) to disable script execution instead. In a future +version, ``"no"`` will be treated as a plain file name. + QEMU Machine Protocol (QMP) commands ------------------------------------ @@ -164,6 +173,15 @@ Use ``job-finalize`` instead. Use ``query-accelerators`` instead. +``"no"`` as value of ``script``/``downscript`` for tap in ``netdev_add`` (since 11.2) +''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' + +The special value ``"no"`` for the ``script`` and ``downscript`` +parameters of ``netdev_add`` with ``type=tap`` disables script +execution. This special treatment of ``"no"`` is deprecated. Use an +empty string instead. In a future version, ``"no"`` will be treated as +a plain file name. + Human Machine Protocol (HMP) commands ------------------------------------- diff --git a/docs/system/i386/microvm.rst b/docs/system/i386/microvm.rst index 1675e37d3e7..077ea15751e 100644 --- a/docs/system/i386/microvm.rst +++ b/docs/system/i386/microvm.rst @@ -79,7 +79,7 @@ legacy ``ISA serial`` device as console:: -serial stdio \ -drive id=test,file=test.img,format=raw,if=none \ -device virtio-blk-device,drive=test \ - -netdev tap,id=tap0,script=no,downscript=no \ + -netdev tap,id=tap0,script=,downscript= \ -device virtio-net-device,netdev=tap0 While the example above works, you might be interested in reducing the @@ -103,7 +103,7 @@ disabled:: -device virtconsole,chardev=virtiocon0 \ -drive id=test,file=test.img,format=raw,if=none \ -device virtio-blk-device,drive=test \ - -netdev tap,id=tap0,script=no,downscript=no \ + -netdev tap,id=tap0,script=,downscript= \ -device virtio-net-device,netdev=tap0 diff --git a/docs/system/i386/xenpvh.rst b/docs/system/i386/xenpvh.rst index 904778e3f5c..862f38830b1 100644 --- a/docs/system/i386/xenpvh.rst +++ b/docs/system/i386/xenpvh.rst @@ -42,7 +42,7 @@ case you need to construct one manually: -vnc none \ -display none \ -device virtio-net-pci,id=nic0,netdev=net0,mac=00:16:3e:5c:81:78 \ - -netdev type=tap,id=net0,ifname=vif3.0-emu,br=xenbr0,script=no,downscript=no \ + -netdev type=tap,id=net0,ifname=vif3.0-emu,br=xenbr0,script=,downscript= \ -smp 4,maxcpus=4 \ -nographic \ -machine xenpvh,ram-low-base=0,ram-low-size=2147483648,ram-high-base=4294967296,ram-high-size=2147483648,pci-ecam-base=824633720832,pci-ecam-size=268435456,pci-mmio-base=4026531840,pci-mmio-size=33554432,pci-mmio-high-base=824902156288,pci-mmio-high-size=68719476736 \ diff --git a/docs/system/ppc/ppce500.rst b/docs/system/ppc/ppce500.rst index c9fe0915dc5..ec5aaf14fd9 100644 --- a/docs/system/ppc/ppce500.rst +++ b/docs/system/ppc/ppce500.rst @@ -158,14 +158,14 @@ interface at PCI address 0.1.0, but we can switch that to an e1000 NIC by: $ qemu-system-ppc64 -M ppce500 -smp 4 -m 2G \ -display none -serial stdio \ -bios u-boot \ - -nic tap,ifname=tap0,script=no,downscript=no,model=e1000 + -nic tap,ifname=tap0,script=,downscript=,model=e1000 The QEMU ``ppce500`` machine can also dynamically instantiate an eTSEC device if “-device eTSEC” is given to QEMU: .. code-block:: bash - -netdev tap,ifname=tap0,script=no,downscript=no,id=net0 -device eTSEC,netdev=net0 + -netdev tap,ifname=tap0,script=,downscript=,id=net0 -device eTSEC,netdev=net0 Root file system on flash drive ------------------------------- diff --git a/docs/system/riscv/microchip-icicle-kit.rst b/docs/system/riscv/microchip-icicle-kit.rst index 9809e94b84b..7fdb96601ad 100644 --- a/docs/system/riscv/microchip-icicle-kit.rst +++ b/docs/system/riscv/microchip-icicle-kit.rst @@ -84,7 +84,7 @@ Then we can boot the machine by: $ qemu-system-riscv64 -M microchip-icicle-kit -smp 5 -m 2G \ -sd path/to/sdcard.img \ -nic user,model=cadence_gem \ - -nic tap,ifname=tap,model=cadence_gem,script=no \ + -nic tap,ifname=tap,model=cadence_gem,script= \ -display none -serial stdio \ -kernel path/to/u-boot/build/dir/u-boot.bin \ -dtb path/to/u-boot/build/dir/u-boot.dtb diff --git a/docs/system/riscv/sifive_u.rst b/docs/system/riscv/sifive_u.rst index 8f55ae8e313..0e4dcf3e70c 100644 --- a/docs/system/riscv/sifive_u.rst +++ b/docs/system/riscv/sifive_u.rst @@ -199,7 +199,7 @@ To boot the VxWorks kernel in QEMU with the ``sifive_u`` machine, use: $ qemu-system-riscv64 -M sifive_u -smp 5 -m 2G \ -display none -serial stdio \ - -nic tap,ifname=tap0,script=no,downscript=no \ + -nic tap,ifname=tap0,script=,downscript= \ -kernel /path/to/vxWorks \ -append "gem(0,0)host:vxWorks h=192.168.200.1 e=192.168.200.2:ffffff00 u=target pw=vxTarget f=0x01" diff --git a/net/tap.c b/net/tap.c index fedd48c48d2..1ec9e5ebe6f 100644 --- a/net/tap.c +++ b/net/tap.c @@ -103,6 +103,8 @@ static bool tap_is_explicit_no_script(const char *script_arg) } if (strcmp(script_arg, "no") == 0) { + warn_report("script=no/downscript=no is deprecated; " + "use script=/downscript= instead"); return true; } diff --git a/qapi/net.json b/qapi/net.json index 8f0915c4d86..ada0329ef9d 100644 --- a/qapi/net.json +++ b/qapi/net.json @@ -399,15 +399,19 @@ # @fds: multiple file descriptors of already opened multiqueue capable # tap # -# @script: script to initialize the interface. An empty string or -# "no" disables script execution. Defaults to +# @script: script to initialize the interface. An empty string +# disables script execution. Defaults to # ``<sysconfdir>/qemu-ifup``, where ``<sysconfdir>`` is the # system configuration directory at build time (typically /etc). +# Using "no" to disable script execution is deprecated (since +# 11.2); use an empty string instead. # -# @downscript: script to shut down the interface. An empty string or -# "no" disables script execution. Defaults to +# @downscript: script to shut down the interface. An empty string +# disables script execution. Defaults to # ``<sysconfdir>/qemu-ifdown``, where ``<sysconfdir>`` is the # system configuration directory at build time (typically /etc). +# Using "no" to disable script execution is deprecated (since +# 11.2); use an empty string instead. # # @br: bridge name (since 2.8) # diff --git a/qemu-options.hx b/qemu-options.hx index 200949655ea..7b9a14f5b38 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -3014,7 +3014,8 @@ DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" " to deconfigure it\n" - " use '[down]script=no' or '[down]script=' to disable script execution\n" + " use '[down]script=' to disable script execution\n" + " ('[down]script=no' is deprecated and will be treated as a file name in future)\n" " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" " configure it\n" " use 'fd=h' to connect to an already opened TAP interface\n" @@ -3553,7 +3554,9 @@ SRST ``<sysconfdir>/qemu-ifup`` and the default network deconfigure script is ``<sysconfdir>/qemu-ifdown``, where ``<sysconfdir>`` is the system configuration directory at build time (typically ``/etc``). - Use ``[down]script=no`` or ``[down]script=`` to disable script execution. + Use ``[down]script=`` to disable script execution. + Using ``[down]script=no`` is deprecated; in a future version it will + be treated as a plain file name. If running QEMU as an unprivileged user, use the network helper to configure the TAP interface and attach it to the bridge. -- 2.43.0

3 4

[PATCH 0/2] bhyve: implement the virDomainRename API
by Roman Bogorodskiy 13 Jul '26

13 Jul '26

Roman Bogorodskiy (2): bhyve: implement the virDomainRename API qemu: qemuDomainRenameCallback: remove unused variables src/bhyve/bhyve_domain.c | 27 +++++++++ src/bhyve/bhyve_domain.h | 1 + src/bhyve/bhyve_driver.c | 122 +++++++++++++++++++++++++++++++++++++++ src/qemu/qemu_driver.c | 4 -- 4 files changed, 150 insertions(+), 4 deletions(-) -- 2.52.0

2 6

[PATCH 0/6] virsh: Add missing TAB completers for several commands
by rsmigiel＠redhat.com 10 Jul '26

10 Jul '26

From: Radoslaw Smigielski <rsmigiel(a)redhat.com> This series adds missing virsh TAB completion callbacks for six command options: - dump --file - blockcopy --dest - detach-interface --type - domdisplay --type - domxml-from-native --format - save --file This is a small step towards closing the missing completers tracked in: https://gitlab.com/libvirt/libvirt/-/work_items/9 As of now there are 29 missing bash completers, the one fixed in this patch is first batch. As some of the patches change only one line, I would apprecate your feedback if these small one should be combined into a single patch? Radoslaw Smigielski (6): virsh: Add completer for '--file' option of 'dump' subcommand virsh: Add completer for '--dest' option of 'blockcopy' command virsh: Add completer for '--type' option of 'detach-interface' command virsh: Add completer for '--type' option of 'domdisplay' command virsh: Add completer for '--format' option of 'domxml-from-native' command virsh: Add completer for '--file' option of 'save' command tools/virsh-completer-domain.c | 49 ++++++++++++++++++++++++++++++++++ tools/virsh-completer-domain.h | 10 +++++++ tools/virsh-domain.c | 6 +++++ 3 files changed, 65 insertions(+) -- 2.54.0

2 11

Limit USB 1.0 (UHCI/OCHI) and 2.0 (EHCI) to non-virt use cases
by Daniel P. Berrangé 09 Jul '26

09 Jul '26

QEMU has implemented four generic USB controllers * UHCI - USB 1.0 only * OHCI - USB 1.0 only * EHCI - USB 2.0 only (must have UHCI companions for 1.0 compat) * XHCI - All of USB 3.0, 2.0, 1.0 in one controller We have two variants of XHCI, the generic one (hcd-xhci.c) and the NEC one (hcd-xhci-nec.c) Historically for security reports we have considered all of them in scope of virtualization, since initially with KVM the XHCI impl was not present in QEMU & thus KVM guests used UHCI/EHCI with USB tablet for a period of time All of the USB subsystem is currently orphaned, so we have no dedicated maintainer available to deal with bug reports (volunteers welcome to step up here...) While the need for USB is reduced given the availability of virtio-input, not all guests have drivers out of the box, so at least USB tablet is still interesting for KVM use cases with some modern OS. It is also not that unusual for people to need USB host device assignment with KVM virt to make various pieces of specialized hardware (security tokens, smart cards, custom dongles, etc) available directly to guests. IOW, we can't entirely exclude USB from virtualization use cases IMHO. In terms of virtualization, XHCI is the only impl that is sensible to use. UHCI/OHCI/EHCI all impose an unreasonable CPU load on any guest usage of USB. XHCI should be supported by any guest OS approx the last 15 years, which should be sufficient for virtualization use cases with OS that are not EOL by their vendor. Thus to reduce our maint burden around security bug handling, it is proposed henceforth to classify UHCI, OHCI and EHCI under the non- virtualization use case and thus be excluded from security bug triage processes. No CVEs would be assigned, bugs would be reported publically in gitlab: https://www.qemu.org/docs/master/system/security.html#non-virtualization-us… The XHCI controller (specifically the hcd-xhci.c variant) would remain as our only option for the virtualization use case, with security process applied to bugs & eligible for CVE assignment: https://www.qemu.org/docs/master/system/security.html#virtualization-use-ca… The other NEC XHCI variant (hcd-xhci-nec.c) would also be treated as non-virtualization use case, since it needlessly duplicates hcd-xhci.c impl and thus is only interesting for emulation of this specific HW variant. NB, there are no functional limitations / restrictions from this policy, it is largely just a semantic exercise. From a management application POV, however, it would strongly suggest that guests be configured with XHCI as the default choice if the user asks for USB, and in turn also imply that '-usb' not be used since that is UHCI/OHCI typically. CC'ing libvirt, though it is really a matter for virt-install/virt-manager/ openstack/kubevirt etc above libvirt to pick their defaults for USB controllers. None the less XHCI would still be in search of a maintainer to step forward and handle ongoing development and maint work. With regards, Daniel -- |: https://berrange.com ~~ https://hachyderm.io/@berrange :| |: https://libvirt.org ~~ https://entangle-photo.org :| |: https://pixelfed.art/berrange ~~ https://fstop138.berrange.com :|

5 7

[PATCH] docs: drvbhyve: document newly added pf check
by Nimish Jain 09 Jul '26

09 Jul '26

Reflects that the pf firewall check was added in virt-host-validate. Signed-off-by: Nimish Jain <unauthorizen(a)gmail.com> --- docs/drvbhyve.rst | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/docs/drvbhyve.rst b/docs/drvbhyve.rst index 2e5e361115..51782f8090 100644 --- a/docs/drvbhyve.rst +++ b/docs/drvbhyve.rst @@ -11,8 +11,8 @@ recommended to use the `latest supported release <https://www.freebsd.org/releases/>`__ to make sure all new features of bhyve are supported. In order to enable bhyve on your FreeBSD host, you'll need -to load the ``vmm`` kernel module. Additionally, ``if_tap`` and ``if_bridge`` -modules should be loaded for networking support. Also, :since:`since 3.2.0` the +to load the ``vmm`` kernel module. Additionally, ``if_tap``, ``if_bridge`` +and ``pf`` modules should be loaded for networking support. Also, :since:`since 3.2.0` the ``virt-host-validate(1)`` supports the bhyve host validation and could be used like this: @@ -21,6 +21,7 @@ like this: $ virt-host-validate bhyve BHYVE: Checking for vmm module : PASS BHYVE: Checking for if_tap module : PASS + BHYVE: Checking for pf module : PASS BHYVE: Checking for if_bridge module : PASS BHYVE: Checking for nmdm module : PASS $ -- 2.39.5 (Apple Git-154)

2 1

[PATCH] docs: drvnetwork: Update sample pf.conf to include NAT forwarding for FreeBSD
by Nimish Jain 09 Jul '26

09 Jul '26

This is beneficial for new users using the 'default' libvirt network configuration on FreeBSD, to get a VM up and running quickly. Also fixes a typo ('netowork') Signed-off-by: Nimish Jain <unauthorizen(a)gmail.com> --- docs/drvnetwork.rst | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/docs/drvnetwork.rst b/docs/drvnetwork.rst index 23082310ba..881b828d5f 100644 --- a/docs/drvnetwork.rst +++ b/docs/drvnetwork.rst @@ -10,14 +10,17 @@ Platform-specific notes FreeBSD ------- -FreeBSD netowork driver uses the pf firewall. Libvirt managed pf rules +FreeBSD network driver uses the pf firewall. Libvirt managed pf rules are created within anchors. Anchors need to be configured manually by -the user. Sample ``/etc/pf.conf`` might look like: +the user. Sample ``/etc/pf.conf`` with a basic NAT configuration +might look like: :: scrub all + nat on em0 from {192.168.122.0/24} to any -> (em0) + nat-anchor "libvirt\*" anchor "libvirt\*" -- 2.39.5 (Apple Git-154)

2 1

[PATCH 0/6] qemu: Support AF_VSOCK transport for QGA communication
by Polina Vishneva 09 Jul '26

09 Jul '26

This series add support for talking to QEMU guest agent via a vsock transport. This transport is attempted when there's no ready virtio-serial channels **and** the domain has a usable vsock CID. AF_VSOCK are sockets too, so most of the virtio-serial/UNIX socket code is reused for everything except the connection lifecycle management (that is, initial connection etc.). Since QGA has no readiness notification mechanism for vsock transport, unlike for virtio-serial transport, we have to knock on the port to probe for readiness. For that, a custom backoff logic with cancellation support is implemented. Both the new virVsockConnectQuiet helper and the vsock QGA connection logic itself are covered by new tests. Polina Vishneva (6): util: Add virVsockConnectQuiet helper qemu: Extract qemuProcessResetAgent helper qemu: Add qemuDomainVsockHasGuestCid helper qemu: Support AF_VSOCK transport for QGA communication tests: Add a unit test for virVsockConnectQuiet() tests: Add a test for qemuConnectAgent() to cover the vsock path src/hypervisor/qemu_agent.c | 73 +++++---- src/hypervisor/qemu_agent.h | 9 ++ src/libvirt_private.syms | 2 + src/qemu/qemu_domain.c | 28 +++- src/qemu/qemu_domain.h | 8 + src/qemu/qemu_driver.c | 16 +- src/qemu/qemu_hotplug.c | 6 + src/qemu/qemu_process.c | 305 +++++++++++++++++++++++++++++++---- src/qemu/qemu_process.h | 2 + src/util/virvsock.c | 71 +++++++- src/util/virvsock.h | 10 ++ tests/meson.build | 3 + tests/qemuagenttest.c | 43 ++++- tests/qemumonitortestutils.c | 119 +++++++++++++- tests/qemumonitortestutils.h | 4 + tests/qemuvsockagentmock.c | 65 ++++++++ tests/virvsockmock.c | 143 ++++++++++++++++ tests/virvsocktest.c | 133 +++++++++++++++ 18 files changed, 963 insertions(+), 77 deletions(-) create mode 100644 tests/qemuvsockagentmock.c create mode 100644 tests/virvsockmock.c create mode 100644 tests/virvsocktest.c -- 2.54.0

1 6