<ank...@nvidia.com> writes: > From: Ankit Agrawal <ank...@nvidia.com> > > NVIDIA GPU's support MIG (Mult-Instance GPUs) feature [1], which allows > partitioning of the GPU device resources (including device memory) into > several (upto 8) isolated instances. Each of the partitioned memory needs > a dedicated NUMA node to operate. The partitions are not fixed and they > can be created/deleted at runtime. > > Unfortunately Linux OS does not provide a means to dynamically create/destroy > NUMA nodes and such feature implementation is not expected to be trivial. The > nodes that OS discovers at the boot time while parsing SRAT remains fixed. So > we utilize the Generic Initiator Affinity structures that allows association > between nodes and devices. Multiple GI structures per BDF is possible, > allowing creation of multiple nodes by exposing unique PXM in each of these > structures. > > Introduce a new acpi-generic-initiator object to allow host admin provide the > device and the corresponding NUMA nodes. Qemu maintain this association and > use this object to build the requisite GI Affinity Structure.
Pardon my ignorance... What makes this object an "initiator", and why is it "generic"? > An admin can provide the range of nodes through a uint16 array host-nodes > and link it to a device by providing its id. Currently, only PCI device is > supported. The following sample creates 8 nodes and link them to the PCI > device dev0: > > -numa node,nodeid=2 \ > -numa node,nodeid=3 \ > -numa node,nodeid=4 \ > -numa node,nodeid=5 \ > -numa node,nodeid=6 \ > -numa node,nodeid=7 \ > -numa node,nodeid=8 \ > -numa node,nodeid=9 \ > -device > vfio-pci-nohotplug,host=0009:01:00.0,bus=pcie.0,addr=04.0,rombar=0,id=dev0 \ > -object acpi-generic-initiator,id=gi0,pci-dev=dev0,host-nodes=2-9 \ Does this link *all* NUMA nodes to dev0? Would an example involving two devices be more instructive? > [1] https://www.nvidia.com/en-in/technologies/multi-instance-gpu > > Signed-off-by: Ankit Agrawal <ank...@nvidia.com> [...] > diff --git a/qapi/qom.json b/qapi/qom.json > index c53ef978ff..efcc4b8dfd 100644 > --- a/qapi/qom.json > +++ b/qapi/qom.json > @@ -794,6 +794,21 @@ > { 'struct': 'VfioUserServerProperties', > 'data': { 'socket': 'SocketAddress', 'device': 'str' } } > > +## > +# @AcpiGenericInitiatorProperties: > +# > +# Properties for acpi-generic-initiator objects. > +# > +# @pci-dev: PCI device ID to be associated with the node > +# > +# @host-nodes: numa node list This feels a bit terse. The commit message makes me guess this specifies the NUMA nodes to be linked to @pci-dev. Correct? > +# > +# Since: 9.0 > +## > +{ 'struct': 'AcpiGenericInitiatorProperties', > + 'data': { 'pci-dev': 'str', > + 'host-nodes': ['uint16'] } } > + > ## > # @RngProperties: > # > @@ -911,6 +926,7 @@ > ## > { 'enum': 'ObjectType', > 'data': [ > + 'acpi-generic-initiator', > 'authz-list', > 'authz-listfile', > 'authz-pam', > @@ -981,6 +997,7 @@ > 'id': 'str' }, > 'discriminator': 'qom-type', > 'data': { > + 'acpi-generic-initiator': 'AcpiGenericInitiatorProperties', > 'authz-list': 'AuthZListProperties', > 'authz-listfile': 'AuthZListFileProperties', > 'authz-pam': 'AuthZPAMProperties',
