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[PATCH v3 1/1] docs : add doc on cpu model and features
by Hector Cao 02 Sep '25

02 Sep '25

Add documentation on the way libvirt displays the Host CPU model and capabilities (features). There is an implicit expectation from users to get the CPU model name matching the CPU model they are running on, however, this does not happen most of the time. As a consequence, having a documentation is useful both for users to align their expectation and for us to point to a place where the situation is clearly explained. Signed-off-by: Hector Cao <hector.cao(a)canonical.com> --- docs/formatcaps.rst | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) diff --git a/docs/formatcaps.rst b/docs/formatcaps.rst index 7e525487e7..3cf83b7c6a 100644 --- a/docs/formatcaps.rst +++ b/docs/formatcaps.rst @@ -97,6 +97,50 @@ The ``<host/>`` element consists of the following child elements: parse this element. In contrast with the former elements, this is repeated for each security model the libvirt daemon currently supports. +Host CPU model and features +^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +As described previously in this section, libvirt exposes to +users the list of Host CPU features. Libvirt has a special way to +expose this list: Instead of providing the full (and thereby often +very long) set of features, libvirt specifies a CPU model as +baseline and additional features on top of it (as can be seen in +`Examples`_ where the baseline is ``Skylake-Client-noTSX-IBRS``). + +The ideal case would be that the baseline CPU model definition matches +exactly the CPU present in the system, and no additional feature is +needed to express the capabilities of the CPU. For example, if you are +running on a Server CPU you bought as ``Icelake`` type, the returned +CPU model name could be ``Icelake-Server``. However, this ideal +situation rarely happens, for two main reasons: + +- Manufacturers do not ship a single type of CPU under a given name, + there are various different SKUs with different features under the + same name. Yet it is not practical to have a database listing all of + those variants. + +- Some features might be in the hardware but unavailable for various + reasons (BIOS and kernel configuration, disabled for security, + ...). One typical example where this situation happens is related to + the `TSX mitigation <https://docs.kernel.org/arch/x86/tsx_async_abort.html>`__. + As a mitigation to the TAA side channel attack, the Linux kernel disables + by default TSX and its 2 features, ``rtm`` and ``hle``. Since many Linux + distributions keep this safer default behavior, these 2 features appear + as missing. + +Because for backward compatibility reasons, host capabilities cannot +list features that would need to be removed from the baseline model to +describe the host CPU, libvirt has to often use a rather old CPU +model, for example, ``Broadwell`` rather than ``Icelake``. Therefore, +users *shouldnot* expect the reported CPU model name to have any +implications other than that of a named baseline to build the complete +available feature set of the Host CPU. + +`Domain capabilities <formatdomaincaps.html#cpu-configuration>`_ do +not have such limitation, and the ``host-model`` CPU definition would +show the correct CPU model in almost all cases. + + Guest capabilities ~~~~~~~~~~~~~~~~~~ -- 2.45.2

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[PATCH 0/3] hw/sd/sdcard: Deprecate support for spec v1.10
by Philippe Mathieu-Daudé 02 Sep '25

02 Sep '25

Deprecate SD spec v1.10, use v3.01 as new default. Philippe Mathieu-Daudé (3): hw/sd/sdcard: Deprecate support for spec v1.10 hw/sd/sdcard: Use spec v3.01 by default hw/sd/sdcard: Remove support for spec v1.10 docs/about/removed-features.rst | 5 +++++ include/hw/sd/sd.h | 1 - hw/sd/sd.c | 14 +++----------- 3 files changed, 8 insertions(+), 12 deletions(-) -- 2.41.0

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[PATCH v2] qapi: net/tap: deprecate vhostforce option
by Vladimir Sementsov-Ogievskiy 01 Sep '25

01 Sep '25

This option doesn't make sense since long ago (10 years!) commit 1e7398a140f7a6 ("vhost: enable vhost without without MSI-X"). Prior 1e7398a140f7a6, to enable vhost for some specific kind of guests (that don't have MSI-X support), you should have set vhostforce=on (with vhost=on or unset). Since 1e7398a140f7a6, guest type doesn't matter, all guests are equal for vhost-enabling options logic. The current logic is: vhost=on / vhost=off : vhostforce ignored, doesn't make sense vhost unset : vhostforce counts, enabling vhost Currently you may enable vhost several ways: - vhost=on - vhostforce=on - vhost=on + vhostforce=on - and even vhost=on + vhostforce=off - they are all equal. Let's finally deprecate the extra option. Also, fix @vhostforce documentation. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov(a)yandex-team.ru> --- v2: - improve wording - add documentation fix docs/about/deprecated.rst | 7 +++++++ qapi/net.json | 11 +++++++++-- 2 files changed, 16 insertions(+), 2 deletions(-) diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst index d50645a071..b17a5a41aa 100644 --- a/docs/about/deprecated.rst +++ b/docs/about/deprecated.rst @@ -516,6 +516,13 @@ 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``. + + VFIO device options ''''''''''''''''''' diff --git a/qapi/net.json b/qapi/net.json index 78bcc9871e..e89c7aff5f 100644 --- a/qapi/net.json +++ b/qapi/net.json @@ -346,13 +346,20 @@ # @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. The @vhostforce +# option is redundant with the @vhost option. If they conflict, +# @vhost takes precedence. Just use @vhost. +# # Since: 1.2 ## { 'struct': 'NetdevTapOptions', @@ -369,7 +376,7 @@ '*vhost': 'bool', '*vhostfd': 'str', '*vhostfds': 'str', - '*vhostforce': 'bool', + '*vhostforce': { 'type': 'bool', 'features': [ 'deprecated' ] }, '*queues': 'uint32', '*poll-us': 'uint32'} } -- 2.48.1

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[PATCH] qapi: net/tap: deprecate vhostforce option
by Vladimir Sementsov-Ogievskiy 01 Sep '25

01 Sep '25

This option simply duplicates the @vhost option since long ago (10 years!) commit 1e7398a140f7a6 ("vhost: enable vhost without without MSI-X"). Let's finally deprecate it. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov(a)yandex-team.ru> --- docs/about/deprecated.rst | 7 +++++++ qapi/net.json | 6 +++++- 2 files changed, 12 insertions(+), 1 deletion(-) diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst index d50645a071..d14cb37480 100644 --- a/docs/about/deprecated.rst +++ b/docs/about/deprecated.rst @@ -516,6 +516,13 @@ 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 just duplicates the main ``vhost`` option. +Use ``vhost`` alone. + + VFIO device options ''''''''''''''''''' diff --git a/qapi/net.json b/qapi/net.json index 78bcc9871e..d1216bb60a 100644 --- a/qapi/net.json +++ b/qapi/net.json @@ -353,6 +353,10 @@ # @poll-us: maximum number of microseconds that could be spent on busy # polling for tap (since 2.7) # +# Features: +# +# @deprecated: Member @vhostforce is deprecated. Simply use @vhost. +# # Since: 1.2 ## { 'struct': 'NetdevTapOptions', @@ -369,7 +373,7 @@ '*vhost': 'bool', '*vhostfd': 'str', '*vhostfds': 'str', - '*vhostforce': 'bool', + '*vhostforce': { 'type': 'bool', 'features': [ 'deprecated' ] }, '*queues': 'uint32', '*poll-us': 'uint32'} } -- 2.48.1

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[PATCH 0/8] qemu-replies-tool: Improvements for .replies comparison
by Peter Krempa 01 Sep '25

01 Sep '25

Add few more stable dumps to help comparing two .replies files (especially useful when updating to new git versions of qemu) Peter Krempa (8): scripts: qemu-replies-tool: Convert the QMP conversation to list of dicts scripts: qemu-replies-tool: Drop specific invocation of marginally useful dump modes scripts: qemu-replies-tool: Dump machine types in --dump-all scripts: qemu-replies-tool: List also data from 'qom-list-properties' scripts: qemu-replies-tool: Prefix output with filename when dumping data for multiple files scripts: qemu-replies-tool: Dump data from query-version/query-target/query-kvm scripts: qemu-replies-tool: Add stable dump of 'query-command-line-options' scripts: qemu-replies-tool: Add option to dump JSON commands that weren't processed by --dump-all scripts/qemu-replies-tool.py | 271 ++++++++++++++++++++++++++--------- 1 file changed, 207 insertions(+), 64 deletions(-) -- 2.51.0

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Release of libvirt-11.7.0
by Jiri Denemark 01 Sep '25

01 Sep '25

The 11.7.0 release of both libvirt and libvirt-python is tagged and signed tarballs are available at https://download.libvirt.org/ https://download.libvirt.org/python/ Thanks everybody who helped with this release by sending patches, reviewing, testing, or providing feedback. Your work is greatly appreciated. * New features * Allow setting the log level of Cloud Hypervisor Users can now configure the verbosity of Cloud Hypervisor by setting the "log_level" option in ch.conf * bhyve: experimental NAT networking support The bhyve driver now has experimental NAT networking support using the Packet Filter (pf) firewall. * bhyve: domain statistics reporting The bhyve driver now supports querying domain block, interface, and memory statistics. Not all statistics fields are supported though. * Improvements * bhyve: improve 'efi' configuration autofill When a domain is configured with ``<os firmware='efi'/>``, NVRAM configuration is now autofilled. Enjoy. Jirka

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[PATCH 0/2] hw/mips: Remove mipssim machine and mipsnet device
by Philippe Mathieu-Daudé 01 Sep '25

01 Sep '25

mipssim machine (single user of mipsnet device) is deprecated since v10.0; remove for 10.2. Philippe Mathieu-Daudé (2): hw/mips: Remove mipssim machine hw/net: Remove mipsnet device model MAINTAINERS | 6 - docs/about/deprecated.rst | 12 - docs/about/removed-features.rst | 5 + docs/system/target-mips.rst | 11 - configs/devices/mips-softmmu/common.mak | 1 - hw/mips/mipssim.c | 249 -------------------- hw/net/mipsnet.c | 297 ------------------------ hw/mips/Kconfig | 7 - hw/mips/meson.build | 1 - hw/net/Kconfig | 3 - hw/net/meson.build | 1 - hw/net/trace-events | 7 - 12 files changed, 5 insertions(+), 595 deletions(-) delete mode 100644 hw/mips/mipssim.c delete mode 100644 hw/net/mipsnet.c -- 2.51.0

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[PATCH v2 0/2] Introduce virDomainBlockRebase2 API
by Nikolai Barybin 29 Aug '25

29 Aug '25

During first series discussion we agreed on having API that do both - block pull and block copy was a mistake. Thus, I present 'block-stream-only' API. Changes since last revision: - Dropped block-copy functionality - Enabled bandwidth units as params, not as a flag - Improved documentation P.S. Not sure we need virsh support at this stage, because current params can be covered with 'virsh blockpull'. But if you propose more params or we want account for future changes, I can add virsh support. Nikolai Barybin (2): api: remote: introduce virDomainBlockRebase2 API qemu: implement driver support for domainBlockRebase2 API include/libvirt/libvirt-domain.h | 43 +++++++++++++++++++++ src/driver-hypervisor.h | 8 ++++ src/libvirt-domain.c | 65 ++++++++++++++++++++++++++++++++ src/libvirt_public.syms | 5 +++ src/qemu/qemu_driver.c | 48 +++++++++++++++++++++++ src/remote/remote_driver.c | 1 + src/remote/remote_protocol.x | 17 ++++++++- src/remote_protocol-structs | 10 +++++ 8 files changed, 196 insertions(+), 1 deletion(-) -- 2.43.5

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[RFC PATCH 0/5] cover letter: qemu: Implement support for iommufd and multiple vSMMUs
by Nathan Chen 29 Aug '25

29 Aug '25

Hi, This is a follow up to the second RFC patchset [0] for supporting multiple vSMMU instances and using iommufd to propagate DMA mappings to kernel for VM-assigned host devices in a qemu VM. This patchset implements support for specifying multiple <iommu> devices within the VM definition when smmuv3Dev IOMMU model is specified, and is tested with Shameer's latest qemu RFC for HW-accelerated vSMMU devices [1] Moreover, it adds a new 'iommufdId' attribute for hostdev devices to be associated with the iommufd object. For instance, specifying the iommufd object and associated hostdev in a VM definition with multiple IOMMUs, 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> <iommufdId>iommufd0</iommufdId> <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> <iommufdId>iommufd0</iommufdId> <address type='pci' domain='0x0000' bus='0x16' slot='0x00' function='0x0'/> </hostdev> <iommu model='smmuv3Dev' parentIdx='1' accel='on'/> <iommu model='smmuv3Dev' parentIdx='2' accel='on'/> </devices> This would get translated to a qemu command line with the arguments below. Note that libvirt will open the /dev/iommu and VFIO cdev, passing the associated fd number to qemu: -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"}' \ -object '{"qom-type":"iommufd","id":"iommufd0","fd":"24"}' \ -device '{"driver":"arm-smmuv3-accel","primary-bus":"pci.1","id":"smmuv3.0","accel":true}' \ -device '{"driver":"arm-smmuv3-accel","primary-bus":"pci.2","id":"smmuv3.1","accel":true}' \ -device '{"driver":"vfio-pci","host":"0009:01:00.0","id":"hostdev0","iommufd":"iommufd0","fd":"22","bus":"pci.21","addr":"0x0"}' \ -device '{"driver":"vfio-pci","host":"0019:01:00.0","id":"hostdev1","iommufd":"iommufd0","fd":"25","bus":"pci.22","addr":"0x0"}' \ Summary of changes: - Separated out commits for smmuv3Dev iommu model support and supporting multiple IOMMU definitions - Made iommufd only a hostdev attribute - Revised smmuv3Dev iommu model definition to reference the controller index instead of assigning it a BDF - Open iommufd FDs from libvirt backend without exposing FDs to XML users - Fixed iommufd path permissions - Matched qemu usage of Shameer's latest RFCv3 This series is on Github: https://github.com/NathanChenNVIDIA/libvirt/tree/smmuv3Dev-iommufd-08-12-25 Thanks, Nathan [0] https://lists.libvirt.org/archives/list/devel@lists.libvirt.org/thread/EASB… [1] https://lore.kernel.org/qemu-devel/20250714155941.22176-1-shameerali.koloth… Signed-off-by: Nathan Chen <nathanc(a)nvidia.com> Nathan Chen (5): qemu: add IOMMU model smmuv3Dev conf: Support multiple smmuv3Dev IOMMU devices qemu: Implement support for associating iommufd to hostdev qemu: open iommufd FDs from libvirt backend qemu: Update Cgroup, namespace, and seclabel for qemu to access iommufd paths docs/formatdomain.rst | 22 ++- src/conf/domain_conf.c | 208 ++++++++++++++++++++++-- src/conf/domain_conf.h | 13 +- src/conf/domain_validate.c | 58 +++++-- src/conf/schemas/domaincommon.rng | 24 ++- src/libvirt_private.syms | 2 + src/qemu/qemu_alias.c | 15 +- src/qemu/qemu_cgroup.c | 61 +++++++ src/qemu/qemu_cgroup.h | 1 + src/qemu/qemu_command.c | 261 ++++++++++++++++++++++-------- src/qemu/qemu_command.h | 3 +- src/qemu/qemu_domain.c | 8 + src/qemu/qemu_domain.h | 7 + src/qemu/qemu_domain_address.c | 33 ++-- src/qemu/qemu_driver.c | 8 +- src/qemu/qemu_hotplug.c | 2 +- src/qemu/qemu_namespace.c | 44 +++++ src/qemu/qemu_postparse.c | 11 +- src/qemu/qemu_process.c | 232 ++++++++++++++++++++++++++ src/qemu/qemu_validate.c | 18 ++- src/security/security_apparmor.c | 11 ++ src/security/security_dac.c | 23 +++ src/security/security_selinux.c | 24 +++ src/util/virpci.c | 68 ++++++++ src/util/virpci.h | 1 + 25 files changed, 1020 insertions(+), 138 deletions(-) -- 2.43.0

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[PATCH v2 0/6] Enable mshv support for Qemu domains
by Praveen K Paladugu 28 Aug '25

28 Aug '25

"[PATCH v3 00/26] Implementing a MSHV (Microsoft Hypervisor) accelerator" patchset in qemu-devel mailing list introduces MSHV support within Qemu. With above patchset, Qemu guests can be started with `-accel mshv` option to use Microsoft Hypervisor (/dev/mshv) as the hypervisor. Retaining Libvirt's naming convention, this translates to `hyperv` domains. Below is an excerpt of the xml to use with this patchset: ``` <domain type='hyperv'> <name>qemu_msh_testv</name> <cpu mode='host-model'/> <os> <type machine='q35'>hvm</type> </os> ... ``` This patch set introduces the necessary changes within libvirt to support Qemu guest with hyperv (mshv) hypervisor. Changes in v2: - Addressed review comments on v1. - Added a test to verify mshv capabilities. Praveen K Paladugu (6): qemu: introduce mshv capabilities qemu: use mshv accel for hyperv domains qemu: add /dev/mshv to default cgroup acl qemu: probe mshv capabilities conf: update capability schema tests: Introduce tests for mshv capabilities src/conf/schemas/capability.rng | 1 + src/qemu/qemu.conf.in | 2 +- src/qemu/qemu_capabilities.c | 61 +- src/qemu/qemu_capabilities.h | 1 + src/qemu/qemu_cgroup.c | 2 +- src/qemu/qemu_command.c | 4 +- src/qemu/qemu_monitor.c | 12 + src/qemu/qemu_monitor.h | 12 +- src/qemu/qemu_monitor_json.c | 32 +- src/qemu/qemu_monitor_json.h | 13 +- src/qemu/test_libvirtd_qemu.aug.in | 3 +- .../caps_11.3.0_x86_64+mshv.replies | 46912 ++++++++++++++++ .../caps_11.3.0_x86_64+mshv.xml | 4996 ++ .../qemucaps2xmloutdata/caps.x86_64+mshv.xml | 29 + 14 files changed, 52060 insertions(+), 20 deletions(-) create mode 100644 tests/qemucapabilitiesdata/caps_11.3.0_x86_64+mshv.replies create mode 100644 tests/qemucapabilitiesdata/caps_11.3.0_x86_64+mshv.xml create mode 100644 tests/qemucaps2xmloutdata/caps.x86_64+mshv.xml -- 2.50.1

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