November 2025 - Devel - libvirt List Archives

[PATCH v5] qapi: net: deprecate vhostforce option
by Vladimir Sementsov-Ogievskiy 13 Nov '25

13 Nov '25

This option for tap and vhost-user netdevs doesn't make sense since long ago (10 years!), starting from commits: 1e7398a140f7a6 ("vhost: enable vhost without without MSI-X") 24f938a682d934 ("vhost user:support vhost user nic for non msi guests") Prior these commits, to enable kernel vhost-net, or vhost-user-net for some specific kind of guests (that don't have MSI-X support), you should have set vhostforce=on. Now guest type doesn't matter, all guests are equal for these options logic. For tap the current logic is: vhost=on / vhost=off : vhostforce ignored, doesn't make sense vhost unset : vhostforce counts, enabling vhost So you may enable vhost for tap several ways: - vhost=on - vhostforce=on - vhost=on + vhostforce=on - and even vhost=on + vhostforce=off - they are all equal. For vhost-user we simply ignore the vhostforce option at all in the code. Let's finally deprecate the extra options. Also, fix @vhostforce documentation everywhere to show the real picture, and update vhost-user test to not use deprecated option. While updating command line options, drop "experimental" word from "experimental in kernel accelerator". vhost-net is in production for years. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov(a)yandex-team.ru> --- v5: update wording and commit message docs/about/deprecated.rst | 11 +++++++++++ qapi/net.json | 18 ++++++++++++++---- qemu-options.hx | 13 +++++-------- tests/qtest/vhost-user-test.c | 2 +- 4 files changed, 31 insertions(+), 13 deletions(-) diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst index dacf2882e4..a781600a2f 100644 --- a/docs/about/deprecated.rst +++ b/docs/about/deprecated.rst @@ -484,6 +484,17 @@ Stream ``reconnect`` (since 9.2) The ``reconnect`` option only allows specifying second granularity timeouts, which is not enough for all types of use cases, use ``reconnect-ms`` instead. +TAP ``vhostforce`` (since 10.2) +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The ``vhostforce`` option is redundant with the ``vhost`` option. +If they conflict, ``vhost`` takes precedence. Just use ``vhost``. + +Vhost-user ``vhostforce`` (since 10.2) +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The ``vhostforce`` option is a no-op. Do not use it. + CPU device properties ''''''''''''''''''''' diff --git a/qapi/net.json b/qapi/net.json index 60d196afe5..e8ccc8afc2 100644 --- a/qapi/net.json +++ b/qapi/net.json @@ -346,13 +346,18 @@ # @vhostfds: file descriptors of multiple already opened vhost net # devices # -# @vhostforce: vhost on for non-MSIX virtio guests +# @vhostforce: enable vhost-net network accelerator. Ignored when +# @vhost is set. # # @queues: number of queues to be created for multiqueue capable tap # # @poll-us: maximum number of microseconds that could be spent on busy # polling for tap (since 2.7) # +# Features: +# +# @deprecated: Member @vhostforce is deprecated. Use @vhost instead. +# # Since: 1.2 ## { 'struct': 'NetdevTapOptions', @@ -369,7 +374,7 @@ '*vhost': 'bool', '*vhostfd': 'str', '*vhostfds': 'str', - '*vhostforce': 'bool', + '*vhostforce': { 'type': 'bool', 'features': [ 'deprecated' ] }, '*queues': 'uint32', '*poll-us': 'uint32'} } @@ -606,17 +611,22 @@ # # @chardev: name of a unix socket chardev # -# @vhostforce: vhost on for non-MSIX virtio guests (default: false). +# @vhostforce: silently ignored, exists just for backward +# compatibility. # # @queues: number of queues to be created for multiqueue vhost-user # (default: 1) (Since 2.5) # +# Features: +# +# @deprecated: Member @vhostforce is deprecated. +# # Since: 2.1 ## { 'struct': 'NetdevVhostUserOptions', 'data': { 'chardev': 'str', - '*vhostforce': 'bool', + '*vhostforce': { 'type': 'bool', 'features': [ 'deprecated' ] }, '*queues': 'int' } } ## diff --git a/qemu-options.hx b/qemu-options.hx index 0223ceffeb..35a70096e8 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -2882,7 +2882,7 @@ DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, #else "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" - " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" + " [,vhostfd=h][,vhostfds=x:y:...:z][,queues=n]\n" " [,poll-us=n]\n" " configure a host TAP network backend with ID 'str'\n" " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" @@ -2898,9 +2898,7 @@ DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" - " use vhost=on to enable experimental in kernel accelerator\n" - " (only has effect for virtio guests which use MSIX)\n" - " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" + " use vhost=on to enable in kernel accelerator\n" " use 'vhostfd=h' to connect to an already opened vhost net device\n" " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" @@ -2991,7 +2989,7 @@ DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, " use 'start-queue=m' to specify the first queue that should be used\n" #endif #ifdef CONFIG_POSIX - "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" + "-netdev vhost-user,id=str,chardev=dev\n" " configure a vhost-user network, backed by a chardev 'dev'\n" #endif #ifdef __linux__ @@ -3882,12 +3880,11 @@ SRST for insertion into the socket map. The combination of 'map-path' and 'sock-fds' together is not supported. -``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` +``-netdev vhost-user,chardev=id[,queues=n]`` Establish a vhost-user netdev, backed by a chardev id. The chardev should be a unix domain socket backed one. The vhost-user uses a specifically defined protocol to pass vhost ioctl replacement - messages to an application on the other end of the socket. On - non-MSIX guests, the feature can be forced with vhostforce. Use + messages to an application on the other end of the socket. Use 'queues=n' to specify the number of queues to be created for multiqueue vhost-user. diff --git a/tests/qtest/vhost-user-test.c b/tests/qtest/vhost-user-test.c index 609ff24059..a4862d7087 100644 --- a/tests/qtest/vhost-user-test.c +++ b/tests/qtest/vhost-user-test.c @@ -46,7 +46,7 @@ #define QEMU_CMD_SHM " -m %d -object memory-backend-shm,id=mem,size=%dM," \ " -numa node,memdev=mem" #define QEMU_CMD_CHR " -chardev socket,id=%s,path=%s%s" -#define QEMU_CMD_NETDEV " -netdev vhost-user,id=hs0,chardev=%s,vhostforce=on" +#define QEMU_CMD_NETDEV " -netdev vhost-user,id=hs0,chardev=%s" #define HUGETLBFS_MAGIC 0x958458f6 -- 2.48.1

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[PATCH 0/1] cpu_map: fix vmx-* features wrong bitmaps
by Hector Cao 12 Nov '25

12 Nov '25

Hello, I'm unable to make virsh capabilities to detect the right CPU model on an Intel Granite Rapids platform. I would expect the get the CPU model defined in one of the src/cpu_map/x86_GraniteRapids*.xml files. The cause of the wrong detection is the fact that some vmx-* are not correctly detected and considered missing on this platform. When I take a look at the src/cpu_map/x86_features.xml file, I think that some of the vmx-* are wrongly defined. Taking as an example the vmx-apicv-xapic feature, it is defined as the first bit in the EAX register when we read the MSR 0x0000048b . But in Intel specification, this feature is represented as the first bit in the EDX register (32 higher bits). You can find in this submission the patch that fixes this issue, and this for all the affected MSRs. I tested this fix on my Granite Rapids platform and the CPU model is now correctly detected. Hector Cao (1): cpu_map: fix vmx-* features wrong bitmaps src/cpu_map/x86_features.xml | 136 +++++++++++++++++------------------ 1 file changed, 68 insertions(+), 68 deletions(-) -- 2.45.2

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[PATCH 0/2] Remove use of deprecated 'xmlIndentTreeOutput' variable from libxml2
by Peter Krempa 11 Nov '25

11 Nov '25

The default from libxml2 is '1' which we wanted. Thus all use in separate processes is okay, and for the few exceptions (see 2/2) the resulting XML is mis-indented but valid for any app which would override it. Peter Krempa (2): virVBoxSnapshotConfSaveVboxFile: Don't modify deprecated 'xmlIndentTreeOutput' virXMLFormatMetadata: Don't modify deprecated 'xmlIndentTreeOutput' src/util/virxml.c | 10 ---------- src/vbox/vbox_snapshot_conf.c | 5 ----- 2 files changed, 15 deletions(-) -- 2.51.1

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[PATCH 0/4] bhyve: support queue configuration for NVMe disks
by Roman Bogorodskiy 11 Nov '25

11 Nov '25

Roman Bogorodskiy (4): conf: domain_validate: make disk queue configuration driver specific bhyve: support queue configuration for NVMe disks bhyve: domain: refactor bhyveDomainDeviceDefValidate() bhyve: domain: improve disks validation src/bhyve/bhyve_command.c | 16 ++- src/bhyve/bhyve_domain.c | 110 +++++++++++++----- src/conf/domain_validate.c | 12 -- src/qemu/qemu_driver.c | 15 +++ src/qemu/qemu_validate.c | 14 +++ .../bhyvexml2argv-disk-virtio-queue-opts.xml | 23 ++++ .../bhyvexml2argvdata/bhyvexml2argv-nvme.args | 2 +- .../bhyvexml2argvdata/bhyvexml2argv-nvme.xml | 2 +- tests/bhyvexml2argvtest.c | 1 + .../bhyvexml2xmlout-nvme.xml | 2 +- 10 files changed, 148 insertions(+), 49 deletions(-) create mode 100644 tests/bhyvexml2argvdata/bhyvexml2argv-disk-virtio-queue-opts.xml -- 2.51.0

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[PATCH 0/7] Fixes for CVE-2025-12748
by Martin Kletzander 11 Nov '25

11 Nov '25

ACL checks were performed after parsing a user provided XML in its entirety which could be written in a way that would make libvirt allocate too much memory and crash. Instead parse just the identifiers out of which only name and UUID are needed for ACL checks, perform those and then parse the whole definition. In order not to pass bogus UUID to the ACL functions, rewrite any generated UUID in the first step with a nil UUID since the ACLs cannot be written to expect a particular generated UUID as that would not make sense. If squashing the patches is preferred, let me know. Fixes: CVE-2025-12748 Reported-by: Святослав Терешин <s.tereshin(a)fobos-nt.ru> Martin Kletzander (7): conf: Add virDomainDefIDsParseString bhyve: Check ACLs before parsing the whole domain XML libxl: Check ACLs before parsing the whole domain XML lxc: Check ACLs before parsing the whole domain XML vz: Check ACLs before parsing the whole domain XML ch: Check ACLs before parsing the whole domain XML qemu: Check ACLs before parsing the whole domain XML src/bhyve/bhyve_driver.c | 24 ++++++++--- src/ch/ch_driver.c | 76 +++++++++++++++++++++++---------- src/conf/domain_conf.c | 29 +++++++++++++ src/conf/domain_conf.h | 3 ++ src/libvirt_private.syms | 1 + src/libxl/libxl_driver.c | 20 ++++++--- src/lxc/lxc_driver.c | 22 +++++++--- src/qemu/qemu_driver.c | 90 ++++++++++++++++++++------------------- src/qemu/qemu_migration.c | 21 ++++++++- src/qemu/qemu_migration.h | 4 +- src/qemu/qemu_saveimage.c | 25 +++++++++-- src/qemu/qemu_saveimage.h | 4 +- src/qemu/qemu_snapshot.c | 4 +- src/vz/vz_driver.c | 18 +++++--- 14 files changed, 243 insertions(+), 98 deletions(-) -- 2.51.2

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Does our interface compatibility promise cover defaults?
by Markus Armbruster 11 Nov '25

11 Nov '25

From about/deprecated.rst: In general features are intended to be supported indefinitely once introduced into QEMU. In the event that a feature needs to be removed, it will be listed in this section. The feature will remain functional for the release in which it was deprecated and one further release. After these two releases, the feature is liable to be removed. Deprecated features may also generate warnings on the console when QEMU starts up, or if activated via a monitor command, however, this is not a mandatory requirement. This obviously applies to syntax and semantics of our external interface. Does it apply to default values there? If no: does this mean we can change defaults without notice? If yes: does this mean any change of defaults needs notice in about/deprecated.rst and the grace period? Note that changing a default is a silent change, like changing semantics / behavior, unlike changing syntax.

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[PATCH] meson: default to system crypto policies where available
by Daniel P. Berrangé 10 Nov '25

10 Nov '25

From: Daniel P. Berrangé <berrange(a)redhat.com> In RHEL and Fedora, the built-in GNUTLS default priority is changed from "NORMAL" to "@SYSTEM", but because libvirt sets an explicit policy with gnutls we don't honour that. Instead we force "NORMAL" unless the 'tls_priority' meson option is changed. In RPM builds, meanwhile, we ask for "@LIBVIRT,SYSTEM" to make it look for a libvirt specific profile first, falling back to "@SYSTEM" This changes the meson option to default to "@LIBVIRT,SYSTEM" if the crypto-policies config is present on the local machine and the meson option -Dsystem=true is given. This gives developers more appropriate default behaviour, matching that seen in package builds. Signed-off-by: Daniel P. Berrangé <berrange(a)redhat.com> --- meson.build | 13 ++++++++++++- meson_options.txt | 2 +- 2 files changed, 13 insertions(+), 2 deletions(-) diff --git a/meson.build b/meson.build index d68b37d0ba..c1871de64c 100644 --- a/meson.build +++ b/meson.build @@ -2035,7 +2035,18 @@ elif get_option('userfaultfd_sysctl').enabled() error('userfaultfd_sysctl option requires sysctl_config to be enabled') endif -conf.set_quoted('TLS_PRIORITY', get_option('tls_priority')) +prio = get_option('tls_priority') +if prio == 'auto' + # If local OS has 'crypto-policies' then default to that + policy = '/etc/crypto-policies/config' + if get_option('system') and \ + run_command('test', '-f', policy, check: false).returncode() == 0 + prio = '@LIBVIRT,SYSTEM' + else + prio = 'NORMAL' + endif +endif +conf.set_quoted('TLS_PRIORITY', prio) # test options diff --git a/meson_options.txt b/meson_options.txt index 3dc3e8667b..8b6b26dfc6 100644 --- a/meson_options.txt +++ b/meson_options.txt @@ -134,4 +134,4 @@ option('ssh_proxy', type: 'feature', value: 'auto', description: 'Build ssh-prox option('sysctl_config', type: 'feature', value: 'auto', description: 'Whether to install sysctl configs') # dep:sysctl_config option('userfaultfd_sysctl', type: 'feature', value: 'auto', description: 'Whether to install sysctl config for enabling unprivileged userfaultfd') -option('tls_priority', type: 'string', value: 'NORMAL', description: 'set the default TLS session priority string') +option('tls_priority', type: 'string', value: 'auto', description: 'set the default TLS session priority string') -- 2.51.1

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[PATCH 0/3] docs: drvbhyve: documentation updates
by Roman Bogorodskiy 10 Nov '25

10 Nov '25

*** BLURB HERE *** Roman Bogorodskiy (3): docs: drvbhyve: document device passthrough docs: drvbhyve: improve the manpage link docs: drvbhyve: add guest-specific nodes section docs/drvbhyve.rst | 42 +++++++++++++++++++++++++++++++++++++++++- 1 file changed, 41 insertions(+), 1 deletion(-) -- 2.51.0

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Downloading/uploading a VM from/to ESXi
by Konstantin Kharlamov 10 Nov '25

10 Nov '25

Hi, I'm in need of functional of downloading and uploading a VM from esxi. libvirt seems to lack it. From what I studied, at least downloading should be implemented by ExportVM SOAP function, and then by getting a list of URLs from its returned lease, while pinging the lease to make sure it doesn't timeout. I'm wondering is there any interest in libvirt in accepting such functional?

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[PATCH 0/5] domain_capabilities: Use virXMLFormatElement() to format XML
by Michal Privoznik 10 Nov '25

10 Nov '25

*** BLURB HERE *** Michal Prívozník (5): domain_capabilities: Move indentation adjustment out of virDomainCapsCPUCustomFormat() domain_capabilities: Rework virDomainCapsCPUCustomFormat() domain_capabilities: Rework virDomainCapsCPUFormat() domain_capabilities: Check NULL in FORMAT_PROLOGUE domain_capabilities: Use virXMLFormatElement() in FORMAT_PROLOGUE and FORMAT_EPILOGUE macros src/conf/domain_capabilities.c | 135 ++++++++++---------- tests/domaincapsdata/bhyve_basic.x86_64.xml | 3 +- tests/domaincapsdata/bhyve_fbuf.x86_64.xml | 3 +- tests/domaincapsdata/bhyve_uefi.x86_64.xml | 3 +- 4 files changed, 68 insertions(+), 76 deletions(-) -- 2.51.0

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