[25.04 FEAT] [VS2214] KVM: Enable dynamic update of vfio-ap mediated devices for management applications - libvirt part

[bugproxy]

Feature Description:

The configuration of a vfio-ap matrix device can be updated while being in use, e.g. by a running KVM guest. However, presently this configuration change can't be performed using the higher level management interfaces and tools, like mdevctl and the libvirt nodedev API. Neither it is possible to observe the dynamic updates at the higher levels. This can lead to confusion and hard-to-debug problems in the field.
We want to enable mdevctl and libvirt to be used to perform dynamic updates of vfio-ap matrix devices. To achieve this, it will be necessary to enable mdevctl to support dynamic updates in principle, but also requires support in the vfio-ap driver to support bulk updates in sysfs (of multiple APQNs in one operation),? enhancements to the ap-check callout of s390-tools to exploit? the vfio-ap specific sysfs interfaces and perform the actual update. Finally, the libvirt nodedev API must be extended to support a modify operation.

[bugproxy (bugproxy)]

------- Comment From <email address hidden> 2025-02-05 18:55 EDT-------
This is included in libvirt v10.1.0

The related upstream commits are:

47e57159b3 virmdev: prepare type and attributes for dual state
c877908e14 node_device: refactor mdev attributes handling
c65c078655 node_device: remove unnecessary checks in virNodeDeviceDefFormat
e67bca23e4 nodedev: add an active config to mdev
6fcf613c6f tools: add option inactive to nodedev-dumpxml
e2c5c47439 nodedev: add persistent and transient filter on list
4476751e53 tools: add switches persistent and transient to nodedev-list
e4abc0789c virsh: doc fix on nodedev-list
69f9e7dbc2 api: add virNodeDeviceUpdate()
582f27ff15 nodedev: Implement virNodeDeviceUpdate
8cb1616226 virsh: add nodedev-update
d36ce2f252 nodedev: allow modify on define of a persistent node device

git tag --contains 47e57159b3
v10.1.0
...

[Frank Heimes (fheimes)]

Thank you for the detailed list of commits.
Since plucky includes libvirt 10.10.0-4ubuntu2,
I'm updating this ticket to "Fix Released" (hence closing as done).