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diff --git a/docs/system/devices/nvme.rst b/docs/system/devices/nvme.rst index b5acb2a..aba2533 100644 --- a/docs/system/devices/nvme.rst +++ b/docs/system/devices/nvme.rst @@ -239,3 +239,85 @@ The virtual namespace device supports DIF- and DIX-based protection information to ``1`` to transfer protection information as the first eight bytes of metadata. Otherwise, the protection information is transferred as the last eight bytes. + +Virtualization Enhancements and SR-IOV (Experimental Support) +------------------------------------------------------------- + +The ``nvme`` device supports Single Root I/O Virtualization and Sharing +along with Virtualization Enhancements. The controller has to be linked to +an NVM Subsystem device (``nvme-subsys``) for use with SR-IOV. + +A number of parameters are present (**please note, that they may be +subject to change**): + +``sriov_max_vfs`` (default: ``0``) + Indicates the maximum number of PCIe virtual functions supported + by the controller. Specifying a non-zero value enables reporting of both + SR-IOV and ARI (Alternative Routing-ID Interpretation) capabilities + by the NVMe device. Virtual function controllers will not report SR-IOV. + +``sriov_vq_flexible`` + Indicates the total number of flexible queue resources assignable to all + the secondary controllers. Implicitly sets the number of primary + controller's private resources to ``(max_ioqpairs - sriov_vq_flexible)``. + +``sriov_vi_flexible`` + Indicates the total number of flexible interrupt resources assignable to + all the secondary controllers. Implicitly sets the number of primary + controller's private resources to ``(msix_qsize - sriov_vi_flexible)``. + +``sriov_max_vi_per_vf`` (default: ``0``) + Indicates the maximum number of virtual interrupt resources assignable + to a secondary controller. The default ``0`` resolves to + ``(sriov_vi_flexible / sriov_max_vfs)`` + +``sriov_max_vq_per_vf`` (default: ``0``) + Indicates the maximum number of virtual queue resources assignable to + a secondary controller. The default ``0`` resolves to + ``(sriov_vq_flexible / sriov_max_vfs)`` + +The simplest possible invocation enables the capability to set up one VF +controller and assign an admin queue, an IO queue, and a MSI-X interrupt. + +.. code-block:: console + + -device nvme-subsys,id=subsys0 + -device nvme,serial=deadbeef,subsys=subsys0,sriov_max_vfs=1, + sriov_vq_flexible=2,sriov_vi_flexible=1 + +The minimum steps required to configure a functional NVMe secondary +controller are: + + * unbind flexible resources from the primary controller + +.. code-block:: console + + nvme virt-mgmt /dev/nvme0 -c 0 -r 1 -a 1 -n 0 + nvme virt-mgmt /dev/nvme0 -c 0 -r 0 -a 1 -n 0 + + * perform a Function Level Reset on the primary controller to actually + release the resources + +.. code-block:: console + + echo 1 > /sys/bus/pci/devices/0000:01:00.0/reset + + * enable VF + +.. code-block:: console + + echo 1 > /sys/bus/pci/devices/0000:01:00.0/sriov_numvfs + + * assign the flexible resources to the VF and set it ONLINE + +.. code-block:: console + + nvme virt-mgmt /dev/nvme0 -c 1 -r 1 -a 8 -n 1 + nvme virt-mgmt /dev/nvme0 -c 1 -r 0 -a 8 -n 2 + nvme virt-mgmt /dev/nvme0 -c 1 -r 0 -a 9 -n 0 + + * bind the NVMe driver to the VF + +.. code-block:: console + + echo 0000:01:00.1 > /sys/bus/pci/drivers/nvme/bind
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