Re: [PATCH v10 5/5] docs: Add generic vhost-vdpa device documentation

[Stefano Garzarella]

On Tue, Dec 13, 2022 at 11:37:35PM +0800, Longpeng (Mike, Cloud Infrastructure 
Service Product Dept.) wrote:
> 在 2022/12/13 22:35, Stefano Garzarella 写道:
> > On Mon, Dec 05, 2022 at 04:49:43PM +0800, Longpeng(Mike) wrote:
> > > From: Longpeng <longpeng2@huawei.com>
> > >
> > > Signed-off-by: Longpeng <longpeng2@huawei.com>
> > > ---
> > > .../devices/vhost-vdpa-generic-device.rst     | 66 +++++++++++++++++++
> > > 1 file changed, 66 insertions(+)
> > > create mode 100644 docs/system/devices/vhost-vdpa-generic-device.rst
> > >
> > > diff --git a/docs/system/devices/vhost-vdpa-generic-device.rst 
> > > b/docs/system/devices/vhost-vdpa-generic-device.rst
> > > new file mode 100644
> > > index 0000000000..7d13359ea1
> > > --- /dev/null
> > > +++ b/docs/system/devices/vhost-vdpa-generic-device.rst
> > > @@ -0,0 +1,66 @@
> > > +
> > > +=========================
> > > +vhost-vDPA generic device
> > > +=========================
> > > +
> > > +This document explains the usage of the vhost-vDPA generic device.
> > > +
> > > +Description
> > > +-----------
> > > +
> > > +vDPA(virtio data path acceleration) device is a device that uses 
> > > a datapath
> > > +which complies with the virtio specifications with vendor 
> > > specific control
> > > +path.
> > > +
> > > +QEMU provides two types of vhost-vDPA devices to enable the vDPA 
> > > device, one
> > > +is type sensitive which means QEMU needs to know the actual device type
> > > +(e.g. net, blk, scsi) and another is called "vhost-vDPA generic 
> > > device" which
> > > +is type insensitive.
> > > +
> > > +The vhost-vDPA generic device builds on the vhost-vdpa subsystem 
> > > and virtio
> > > +subsystem. It is quite small, but it can support any type of 
> > > virtio device.
> > > +
> >
> > Maybe we can also add a minimum requirement section (e.g. we needs 
> > at least Linux v5.18 for VHOST_VDPA_GET_VQS_COUNT)
> Ok.
>
> > > +Examples
> > > +--------
> > > +
> > > +1. Please make sure the modules listed bellow are installed:
> > > +    vhost.ko
> > > +    vhost_iotlb.ko
> > > +    vdpa.ko
> > > +    vhost_vdpa.ko
> > > +
> > > +
> > > +2. Prepare the vhost-vDPA backends, here is an example using 
> > > vdpa_sim_blk
> > > +   device:
> > > +
> > > +::
> >
> > Should we add also a `modprobe vhost-vdpa` step?
> This is already described in Step 1.

Ah sorry, I had interpreted it as having those modules compiled and 
available, not loaded.
Maybe better to replace "installed", with "loaded".

Although IMHO we can remove "Step 1" and add "modprobe vhost-vdpa" here.
The others are all dependencies that are automatically loaded.

Thanks,
Stefano