Re: [PATCH v8 5/5] docs: Add generic vhost-vdpa device documentation

[Longpeng (Mike, Cloud Infrastructure Service Product Dept.)]

在 2022/11/8 10:42, Jason Wang 写道:
> On Tue, Nov 8, 2022 at 8:42 AM Longpeng(Mike) <longpeng2@huawei.com> wrote:
> > From: Longpeng <longpeng2@huawei.com>
> >
> > Signed-off-by: Longpeng <longpeng2@huawei.com>
> > ---
> >   docs/system/devices/vhost-vdpa-device.rst | 43 +++++++++++++++++++++++
> >   1 file changed, 43 insertions(+)
> >   create mode 100644 docs/system/devices/vhost-vdpa-device.rst
> >
> > diff --git a/docs/system/devices/vhost-vdpa-device.rst 
> > b/docs/system/devices/vhost-vdpa-device.rst
> > new file mode 100644
> > index 0000000000..b758c4fce6
> > --- /dev/null
> > +++ b/docs/system/devices/vhost-vdpa-device.rst
>
> If the doc is for a general vhost-vDPA device, we'd better have a better name?

How about general-vhost-vdpa-device.rst?

On the other hand, this series focuses on the general vhost-vDPA device, 
so the doc is for it. It's ok if you want one doc includes both, then I 
think it should move out of this series.


> > @@ -0,0 +1,43 @@
> > +
> > +=========================
> > +generic vhost-vdpa device
> > +=========================
> > +
> > +This document explains the usage of the generic vhost vdpa 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 "generic vdpa device" which is
> > +type insensitive (likes vfio-pci).
>
> Same as above, if this document is focused on the general vhost-vDPA
> device, we'd better emphasize it. And I don't think mention vfio-pci
> is good idea here since those two are different from a lot of places,
> (e.g the general vhost-vdpa is not transport specific, as demonstrated
> below).

Ok, got it.

> Thanks
>
> > +
> > +Examples
> > +--------
> > +
> > +Prepare the vhost-vdpa backends first:
> > +
> > +::
> > +  host# ls -l /dev/vhost-vdpa-*
> > +  crw------- 1 root root 236, 0 Nov  2 00:49 /dev/vhost-vdpa-0
> > +
> > +Start QEMU with virtio-mmio bus:
> > +
> > +::
> > +  host# qemu-system                                                  \
> > +      -M microvm -m 512 -smp 2 -kernel ... -initrd ...               \
> > +      -device vhost-vdpa-device,vhostdev=/dev/vhost-vdpa-0           \
> > +      ...
> > +
> > +Start QEMU with virtio-pci bus:
> > +
> > +::
> > +  host# qemu-system                                                  \
> > +      -M pc -m 512 -smp 2                                            \
> > +      -device vhost-vdpa-device-pci,vhostdev=/dev/vhost-vdpa-0       \
> > +      ...
> > --
> > 2.23.0
>
> .