[2/3] doc: update vhost sample app docs

  Vhost sample app documentation describes parameters that are not in the
code and ommits parameters that exist. Also switching the order of
sections on running vhost and VM, since the --client parameter in the
sample line requires a socket to be created by VM. Removing uio
references and updating with vfio-pci. Finally aligining app
name to the binary output by the meson build system.

Signed-off-by: Herakliusz Lipiec <herakliusz.lipiec@intel.com>
---
 doc/guides/sample_app_ug/vhost.rst | 73 ++++++++++++++++--------------
 1 file changed, 38 insertions(+), 35 deletions(-)
  

Hi Herakliusz,

Thanks for the clean-up! Comments inline.

> -----Original Message-----
> From: Lipiec, Herakliusz <herakliusz.lipiec@intel.com>
> Sent: Tuesday, June 7, 2022 7:49 PM
> To: maxime.coquelin@redhat.com; Xia, Chenbo <chenbo.xia@intel.com>;
> Richardson, Bruce <bruce.richardson@intel.com>
> Cc: dev@dpdk.org; Lipiec, Herakliusz <herakliusz.lipiec@intel.com>
> Subject: [PATCH 2/3] doc: update vhost sample app docs
> 
> Vhost sample app documentation describes parameters that are not in the
> code and ommits parameters that exist. Also switching the order of

Omits?

> sections on running vhost and VM, since the --client parameter in the
> sample line requires a socket to be created by VM. Removing uio
> references and updating with vfio-pci. Finally aligining app

Aligning?

> name to the binary output by the meson build system.
> 
> Signed-off-by: Herakliusz Lipiec <herakliusz.lipiec@intel.com>
> ---
>  doc/guides/sample_app_ug/vhost.rst | 73 ++++++++++++++++--------------
>  1 file changed, 38 insertions(+), 35 deletions(-)
> 
> diff --git a/doc/guides/sample_app_ug/vhost.rst
> b/doc/guides/sample_app_ug/vhost.rst
> index a6ce4bc8ac..298fa90a83 100644
> --- a/doc/guides/sample_app_ug/vhost.rst
> +++ b/doc/guides/sample_app_ug/vhost.rst
> @@ -17,10 +17,10 @@ Testing steps
>  -------------
> 
>  This section shows the steps how to test a typical PVP case with this
> -vhost-switch sample, whereas packets are received from the physical NIC
> +dpdk-vhost sample, whereas packets are received from the physical NIC
>  port first and enqueued to the VM's Rx queue. Through the guest testpmd's
>  default forwarding mode (io forward), those packets will be put into
> -the Tx queue. The vhost-switch example, in turn, gets the packets and
> +the Tx queue. The dpdk-vhost example, in turn, gets the packets and
>  puts back to the same physical NIC port.
> 
>  Build
> @@ -33,18 +33,6 @@ The application is located in the ``vhost`` sub-
> directory.
>  .. note::
>     In this example, you need build DPDK both on the host and inside guest.
> 
> -Start the vswitch example
> -~~~~~~~~~~~~~~~~~~~~~~~~~
> -
> -.. code-block:: console
> -
> -        ./dpdk-vhost-switch -l 0-3 -n 4 --socket-mem 1024  \
> -             -- --socket-file /tmp/sock0 --client \
> -             ...
> -
> -Check the `Parameters`_ section for the explanations on what do those
> -parameters mean.
> -
>  .. _vhost_app_run_vm:
> 
>  Start the VM
> @@ -66,6 +54,19 @@ Start the VM
>      some specific features, a higher version might be need. Such as
>      QEMU 2.7 (or above) for the reconnect feature.
> 
> +
> +Start the vswitch example
> +~~~~~~~~~~~~~~~~~~~~~~~~~
> +
> +.. code-block:: console
> +
> +        ./dpdk-vhost -l 0-3 -n 4 --socket-mem 1024  \
> +             -- --socket-file /tmp/sock0 --client \
> +             ...
> +
> +Check the `Parameters`_ section for the explanations on what do those
> +parameters mean.
> +
>  .. _vhost_app_run_dpdk_inside_guest:
> 
>  Run testpmd inside guest
> @@ -77,8 +78,8 @@ could be done by:
> 
>  .. code-block:: console
> 
> -   modprobe uio_pci_generic
> -   dpdk/usertools/dpdk-devbind.py -b uio_pci_generic 0000:00:04.0
> +   modprobe vfio-pci
> +   dpdk/usertools/dpdk-devbind.py -b vfio-pci 0000:00:04.0
> 
>  Then start testpmd for packet forwarding testing.
> 
> @@ -87,13 +88,16 @@ Then start testpmd for packet forwarding testing.
>      ./<build_dir>/app/dpdk-testpmd -l 0-1 -- -i
>      > start tx_first
> 
> +For more information about vIOMMU and NO-IOMMU and VFIO please refer to
> +:doc:`/../linux_gsg/linux_drivers` section of the DPDK Getting started
> guide.
> +

Good note. This also makes me realize the no-iommu section there does not
work for latest kernel now. May need a patch later. 

>  Inject packets
>  --------------
> 
> -While a virtio-net is connected to vhost-switch, a VLAN tag starts with
> +While a virtio-net is connected to dpdk-vhost, a VLAN tag starts with
>  1000 is assigned to it. So make sure configure your packet generator
>  with the right MAC and VLAN tag, you should be able to see following
> -log from the vhost-switch console. It means you get it work::
> +log from the dpdk-vhost console. It means you get it work::
> 
>      VHOST_DATA: (0) mac 52:54:00:00:00:14 and vlan 1000 registered
> 
> @@ -146,26 +150,10 @@ The rx-retry-delay option specifies the timeout (in
> micro seconds) between
>  retries on an RX burst, it takes effect only when rx retry is enabled.
> The
>  default value is 15.
> 
> -**--dequeue-zero-copy**
> -Dequeue zero copy will be enabled when this option is given. it is worth
> to
> -note that if NIC is bound to driver with iommu enabled, dequeue zero copy
> -cannot work at VM2NIC mode (vm2vm=0) due to currently we don't setup
> iommu
> -dma mapping for guest memory.
> -
> -**--vlan-strip 0|1**
> -VLAN strip option is removed, because different NICs have different
> behaviors
> -when disabling VLAN strip. Such feature, which heavily depends on
> hardware,
> -should be removed from this example to reduce confusion. Now, VLAN strip
> is
> -enabled and cannot be disabled.
> -
>  **--builtin-net-driver**
>  A very simple vhost-user net driver which demonstrates how to use the
> generic
>  vhost APIs will be used when this option is given. It is disabled by
> default.
> 
> -**--dma-type**
> -This parameter is used to specify DMA type for async vhost-user net
> driver which
> -demonstrates how to use the async vhost APIs. It's used in combination
> with dmas.
> -
>  **--dmas**
>  This parameter is used to specify the assigned DMA device of a vhost
> device.
>  Async vhost-user net driver will be used if --dmas is set. For example
> @@ -173,6 +161,20 @@ Async vhost-user net driver will be used if --dmas is
> set. For example
>  device 0 enqueue operation and use DMA channel 00:04.1 for vhost device 1
>  enqueue operation.
> 
> +**--total-num-mbufs 0-N**
> +This parameter sets the number of mbufs to be allocated in mbuf pools,
> +the default value is 147456. This is can be used if launch of a port
> fails
> +due to shortage of mbufs.
> +
> +**--tso 0|1**
> +Disables/enables TCP segment offload.
> +
> +**--tx-csum 0|1**
> +Disables/enables TX checksum offload.
> +
> +**-p mask**
> +Number of ports to use.

This should be described as 'Port mask which specifies the ports to be used'

Thanks,
Chenbo

> +
>  Common Issues
>  -------------
> 
> @@ -201,7 +203,8 @@ Common Issues
> 
>    mbuf pool size is dependent on the MAX_QUEUES configuration, if NIC's
>    max queue number is larger than 128, device start will fail due to
> -  insufficient mbuf.
> +  insufficient mbuf. This can be adjusted using ``--total-num-mbufs``
> +  parameter.
> 
>  * Option "builtin-net-driver" is incompatible with QEMU
> 
> --
> 2.36.1