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

[longpeng2--- via <qemu-devel@nongnu.org>]

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
>>
> 
> .