Add documentation for the new <acpi nodeset="..."> element in hostdev, which allows associating devices with ACPI Generic Initiator objects in QEMU. A typical use case is NVIDIA Multi-Instance GPU (MIG), where a physical GPU is partitioned into multiple isolated instances, each tied to one or more virtual NUMA nodes. The documentation includes an example showing how to configure <numa> cells together with a MIG device. Signed-off-by: Andrea Righi <arighi@nvidia.com> --- docs/formatdomain.rst | 49 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+) diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst index 9f7311b6d5..24f7cdd018 100644 --- a/docs/formatdomain.rst +++ b/docs/formatdomain.rst @@ -4894,6 +4894,55 @@ or: host device. :since:`Since 1.0.6`, but only works as expected :since:`since 1.2.2`. +ACPI Generic Initiators +^^^^^^^^^^^^^^^^^^^^^^^^ + +A host device may include an ``<acpi>`` element to create ACPI Generic +Initiator objects for the device in QEMU. + +This can be used for **NVIDIA Multi-Instance GPU (MIG)** configurations, +where a physical GPU is partitioned into multiple isolated instances, each +associated with one or more virtual NUMA nodes. + +By attaching an ``<acpi nodeset=.../>`` element to the MIG device in the +domain XML, the guest will configure the correct partitioning for that +instance. + +.. code-block:: xml + + <numa> + <cell id='0' cpus='0-15' memory='8388608' unit='KiB'/> + <cell id='1' memory='0' unit='KiB'/> + <cell id='2' memory='0' unit='KiB'/> + <cell id='3' memory='0' unit='KiB'/> + <cell id='4' memory='0' unit='KiB'/> + <cell id='5' memory='0' unit='KiB'/> + <cell id='6' memory='0' unit='KiB'/> + <cell id='7' memory='0' unit='KiB'/> + <cell id='8' memory='0' unit='KiB'/> + </numa> + ... + <hostdev mode='subsystem' type='pci' managed='yes'> + <source> + <address domain='0x0000' bus='0x06' slot='0x12' function='0x1'/> + </source> + <acpi nodeset='1-8'/> + <address type='pci' domain='0x0000' bus='0x00' + slot='0x02' function='0x0'/> + </hostdev> + +Attributes of ``<acpi>``: + +``nodeset`` + A list of NUMA node IDs that will be associated with the device. + Each node in the set causes libvirt to create an + ``acpi-generic-initiator`` object in QEMU, tied to this device. + + The value uses the standard libvirt *nodeset* syntax (e.g. ``0-3,5``). + +If the ``<acpi>`` element is omitted, no acpi-generic-initiator objects are +created for the device. + Block / character devices ^^^^^^^^^^^^^^^^^^^^^^^^^ -- 2.51.0