vfio/pds: Add Kconfig and documentation

Add Kconfig entries and pds-vfio-pci.rst. Also, add an entry in the
MAINTAINERS file for this new driver.

It's not clear where documentation for vendor specific VFIO
drivers should live, so just re-use the current amd
ethernet location.

Signed-off-by: Brett Creeley <brett.creeley@amd.com>
Signed-off-by: Shannon Nelson <shannon.nelson@amd.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20230807205755.29579-9-brett.creeley@amd.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

2 files changed, 80 insertions, 0 deletions

diff --git a/Documentation/networking/device_drivers/ethernet/amd/pds_vfio_pci.rst b/Documentation/networking/device_drivers/ethernet/amd/pds_vfio_pci.rst
new file mode 100644
index 000000000000..7a6bc848a2b2
--- /dev/null
+++ b/Documentation/networking/device_drivers/ethernet/amd/pds_vfio_pci.rst
@@ -0,0 +1,79 @@
+.. SPDX-License-Identifier: GPL-2.0+
+.. note: can be edited and viewed with /usr/bin/formiko-vim
+
+==========================================================
+PCI VFIO driver for the AMD/Pensando(R) DSC adapter family
+==========================================================
+
+AMD/Pensando Linux VFIO PCI Device Driver
+Copyright(c) 2023 Advanced Micro Devices, Inc.
+
+Overview
+========
+
+The ``pds-vfio-pci`` module is a PCI driver that supports Live Migration
+capable Virtual Function (VF) devices in the DSC hardware.
+
+Using the device
+================
+
+The pds-vfio-pci device is enabled via multiple configuration steps and
+depends on the ``pds_core`` driver to create and enable SR-IOV Virtual
+Function devices.
+
+Shown below are the steps to bind the driver to a VF and also to the
+associated auxiliary device created by the ``pds_core`` driver. This
+example assumes the pds_core and pds-vfio-pci modules are already
+loaded.
+
+.. code-block:: bash
+  :name: example-setup-script
+
+  #!/bin/bash
+
+  PF_BUS="0000:60"
+  PF_BDF="0000:60:00.0"
+  VF_BDF="0000:60:00.1"
+
+  # Prevent non-vfio VF driver from probing the VF device
+  echo 0 > /sys/class/pci_bus/$PF_BUS/device/$PF_BDF/sriov_drivers_autoprobe
+
+  # Create single VF for Live Migration via pds_core
+  echo 1 > /sys/bus/pci/drivers/pds_core/$PF_BDF/sriov_numvfs
+
+  # Allow the VF to be bound to the pds-vfio-pci driver
+  echo "pds-vfio-pci" > /sys/class/pci_bus/$PF_BUS/device/$VF_BDF/driver_override
+
+  # Bind the VF to the pds-vfio-pci driver
+  echo "$VF_BDF" > /sys/bus/pci/drivers/pds-vfio-pci/bind
+
+After performing the steps above, a file in /dev/vfio/<iommu_group>
+should have been created.
+
+
+Enabling the driver
+===================
+
+The driver is enabled via the standard kernel configuration system,
+using the make command::
+
+  make oldconfig/menuconfig/etc.
+
+The driver is located in the menu structure at:
+
+  -> Device Drivers
+    -> VFIO Non-Privileged userspace driver framework
+      -> VFIO support for PDS PCI devices
+
+Support
+=======
+
+For general Linux networking support, please use the netdev mailing
+list, which is monitored by Pensando personnel::
+
+  netdev@vger.kernel.org
+
+For more specific support needs, please use the Pensando driver support
+email::
+
+  drivers@pensando.io
diff --git a/Documentation/networking/device_drivers/ethernet/index.rst b/Documentation/networking/device_drivers/ethernet/index.rst
index 94ecb67c0885..9827e816084b 100644
--- a/Documentation/networking/device_drivers/ethernet/index.rst
+++ b/Documentation/networking/device_drivers/ethernet/index.rst
@@ -16,6 +16,7 @@ Contents:
    altera/altera_tse
    amd/pds_core
    amd/pds_vdpa
+   amd/pds_vfio_pci
    aquantia/atlantic
    chelsio/cxgb
    cirrus/cs89x0