Laurent Vivier <lviv...@redhat.com> writes:
> On 24/06/2025 10:16, Markus Armbruster wrote:
>> Laurent Vivier <lviv...@redhat.com> writes:
>>
>>> This commit introduces support for passt as a new network backend.
>>> passt is an unprivileged, user-mode networking solution that provides
>>> connectivity for virtual machines by launching an external helper process.
>>>
>>> The implementation reuses the generic stream data handling logic. It
>>> launches the passt binary using GSubprocess, passing it a file
>>> descriptor from a socketpair() for communication. QEMU connects to
>>> the other end of the socket pair to establish the network data stream.
>>>
>>> The PID of the passt daemon is tracked via a temporary file to
>>> ensure it is terminated when QEMU exits.
>>>
>>> Signed-off-by: Laurent Vivier <lviv...@redhat.com>
>>
>> [...]
>>
>>> diff --git a/qapi/net.json b/qapi/net.json
>>> index 97ea1839813b..76d7654414f7 100644
>>> --- a/qapi/net.json
>>> +++ b/qapi/net.json
>>> @@ -112,6 +112,125 @@
>>> 'data': {
>>> 'str': 'str' } }
>>>
>>> +##
>>> +# @NetDevPasstOptions:
>>> +#
>>> +# Unprivileged user-mode network connectivity using passt
>>> +#
>>> +# @path: path to passt binary
>>
>> I'd prefer a more descriptive name.
>>
>> Elsewhere in this file, we refer to programs like this:
>>
>> # @script: script to initialize the interface
>> #
>> # @downscript: script to shut down the interface
>>
>> passt isn't a script, of course.
>>
>> I don't know, perhaps
>>
>> # @passt-filename: the passt program to run.
>>
>> or even
>>
>> # @passt: Filename of the passt program to run.
>>
>>> +#
>>> +# @quiet: don't print informational messages
>>
>> What does the printing? A peek at the code I snipped suggests this flag
>> is passed to the passt binary as --quiet. Correct?
>>
>>> +#
>>> +# @debug: be verbose
>>> +#
>>> +# @trace: extra verbose
>>
>> Likewise for these two.
>>
>>> +#
>>> +# @vhost-user: enable vhost-user
[...]
>>> +# @udp-ports: UDP ports to forward
>>
>> Is there anything in this struct that configures qemu-system-FOO itself,
>> i.e. isn't just passed to passt?
>>
>
> Yes, all parameters are just passed to passt.
>
> Do you think it's better not to add all these parameters to netdev backend
> but only one
> generic containing the passt command line parameters?
I'm not sure.
Thoughts from libvirt's perspective?
