Date:   Thu, 23 Mar 2023 13:22:04 +0800
From:   Jason Wang <jasowang@...hat.com>
To:     Shannon Nelson <shannon.nelson@....com>
Cc:     mst@...hat.com, virtualization@...ts.linux-foundation.org,
        brett.creeley@....com, davem@...emloft.net, netdev@...r.kernel.org,
        kuba@...nel.org, drivers@...sando.io
Subject: Re: [PATCH v3 virtio 8/8] pds_vdpa: pds_vdps.rst and Kconfig

On Thu, Mar 23, 2023 at 3:11 AM Shannon Nelson <shannon.nelson@....com> wrote:
>
> Add the documentation and Kconfig entry for pds_vdpa driver.
>
> Signed-off-by: Shannon Nelson <shannon.nelson@....com>
> ---
>  .../device_drivers/ethernet/amd/pds_vdpa.rst  | 84 +++++++++++++++++++
>  .../device_drivers/ethernet/index.rst         |  1 +

I wonder if it's better to have a dedicated directory for vDPA.

>  MAINTAINERS                                   |  4 +
>  drivers/vdpa/Kconfig                          |  8 ++
>  4 files changed, 97 insertions(+)
>  create mode 100644 Documentation/networking/device_drivers/ethernet/amd/pds_vdpa.rst
>
> diff --git a/Documentation/networking/device_drivers/ethernet/amd/pds_vdpa.rst b/Documentation/networking/device_drivers/ethernet/amd/pds_vdpa.rst
> new file mode 100644
> index 000000000000..d41f6dd66e3e
> --- /dev/null
> +++ b/Documentation/networking/device_drivers/ethernet/amd/pds_vdpa.rst
> @@ -0,0 +1,84 @@
> +.. SPDX-License-Identifier: GPL-2.0+
> +.. note: can be edited and viewed with /usr/bin/formiko-vim
> +
> +==========================================================
> +PCI vDPA driver for the AMD/Pensando(R) DSC adapter family
> +==========================================================
> +
> +AMD/Pensando vDPA VF Device Driver
> +Copyright(c) 2023 Advanced Micro Devices, Inc
> +
> +Overview
> +========
> +
> +The ``pds_vdpa`` driver is an auxiliary bus driver that supplies
> +a vDPA device for use by the virtio network stack.  It is used with
> +the Pensando Virtual Function devices that offer vDPA and virtio queue
> +services.  It depends on the ``pds_core`` driver and hardware for the PF
> +and VF PCI handling as well as for device configuration services.
> +
> +Using the device
> +================
> +
> +The ``pds_vdpa`` 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.
> +
> +.. code-block:: bash
> +
> +  #!/bin/bash
> +
> +  modprobe pds_core
> +  modprobe vdpa
> +  modprobe pds_vdpa
> +
> +  PF_BDF=`grep -H "vDPA.*1" /sys/kernel/debug/pds_core/*/viftypes | head -1 | awk -F / '{print $6}'`

This seems to require debugfs, I wonder if it's better to switch to
using /sys/bus/pci ?

Others look good.

Thanks

> +
> +  # Enable vDPA VF auxiliary device(s) in the PF
> +  devlink dev param set pci/$PF_BDF name enable_vnet value true cmode runtime
> +
> +  # Create a VF for vDPA use
> +  echo 1 > /sys/bus/pci/drivers/pds_core/$PF_BDF/sriov_numvfs
> +
> +  # Find the vDPA services/devices available
> +  PDS_VDPA_MGMT=`vdpa mgmtdev show | grep vDPA | head -1 | cut -d: -f1`
> +
> +  # Create a vDPA device for use in virtio network configurations
> +  vdpa dev add name vdpa1 mgmtdev $PDS_VDPA_MGMT mac 00:11:22:33:44:55
> +
> +  # Set up an ethernet interface on the vdpa device
> +  modprobe virtio_vdpa
> +
> +
> +
> +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
> +    -> Network device support (NETDEVICES [=y])
> +      -> Ethernet driver support
> +        -> Pensando devices
> +          -> Pensando Ethernet PDS_VDPA Support
> +
> +Support
> +=======
> +
> +For general Linux networking support, please use the netdev mailing
> +list, which is monitored by Pensando personnel::
> +
> +  netdev@...r.kernel.org
> +
> +For more specific support needs, please use the Pensando driver support
> +email::
> +
> +  drivers@...sando.io
> diff --git a/Documentation/networking/device_drivers/ethernet/index.rst b/Documentation/networking/device_drivers/ethernet/index.rst
> index eaaf284e69e6..88dd38c7eb6d 100644
> --- a/Documentation/networking/device_drivers/ethernet/index.rst
> +++ b/Documentation/networking/device_drivers/ethernet/index.rst
> @@ -14,6 +14,7 @@ Contents:
>     3com/vortex
>     amazon/ena
>     amd/pds_core
> +   amd/pds_vdpa
>     altera/altera_tse
>     aquantia/atlantic
>     chelsio/cxgb
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 95b5f25a2c06..2af133861068 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -22108,6 +22108,10 @@ SNET DPU VIRTIO DATA PATH ACCELERATOR
>  R:     Alvaro Karsz <alvaro.karsz@...id-run.com>
>  F:     drivers/vdpa/solidrun/
>
> +PDS DSC VIRTIO DATA PATH ACCELERATOR
> +R:     Shannon Nelson <shannon.nelson@....com>
> +F:     drivers/vdpa/pds/
> +
>  VIRTIO BALLOON
>  M:     "Michael S. Tsirkin" <mst@...hat.com>
>  M:     David Hildenbrand <david@...hat.com>
> diff --git a/drivers/vdpa/Kconfig b/drivers/vdpa/Kconfig
> index cd6ad92f3f05..c910cb119c1b 100644
> --- a/drivers/vdpa/Kconfig
> +++ b/drivers/vdpa/Kconfig
> @@ -116,4 +116,12 @@ config ALIBABA_ENI_VDPA
>           This driver includes a HW monitor device that
>           reads health values from the DPU.
>
> +config PDS_VDPA
> +       tristate "vDPA driver for AMD/Pensando DSC devices"
> +       depends on PDS_CORE
> +       help
> +         VDPA network driver for AMD/Pensando's PDS Core devices.
> +         With this driver, the VirtIO dataplane can be
> +         offloaded to an AMD/Pensando DSC device.
> +
>  endif # VDPA
> --
> 2.17.1
>

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