Re: [PATCH v2 3/5] a standone-alone tool to directly share disk image file via vhost-user protocol

[Coiby Xu]

Hi Kevin,

> Yes, I think at least for the moment it should work fine this way.
> Eventually, I'd like to integrate it with --export (and associated QMP
> commands, which are still to be created), too. Maybe at that point we
> want to make the QOM object not user creatable any more.

Does it mean TYPE_USER_CREATABLE interface in QOM will become
deprecated in the future? I'm curious what are the reasons for making
QOM object no user creatable? Because we may still need to start
vhost-user block device backend through HMP or QMP instead of stating
it as a standalone-alone daemon.

> As for test cases, do you think it would be hard to just modify the
> tests to send an explicit 'quit' command to the daemon?

Accroding to https://patchew.org/QEMU/address@hidden/address@hidden/,

> +static bool exit_requested = false;
> +
> +void qemu_system_killed(int signal, pid_t pid)
> +{
> +    exit_requested = true;
> +}

if exit_requested = true, qemu-storage-daemon will exit the main loop
and then quit. So is calling qemu_system_killed by what you means "to
send an explicit 'quit' command to the daemon"?

On Fri, Jan 17, 2020 at 6:12 PM Kevin Wolf <address@hidden> wrote:
>
> Am 17.01.2020 um 09:12 hat Coiby Xu geschrieben:
> > Excellent! I will add an option (or object property) for
> > vhost-user-blk server oject which will tell the daemon process to exit
> > when the client disconnects, thus "make check-qtest" will not get held
> > by this daemon process. After that since Kevin's qemu-storage-daemon
> > support "-object" option
> > (https://patchew.org/QEMU/address@hidden/address@hidden/)
> > and vhost-user-server is a user-creatable QOM object, it will work out
> > of the box.
>
> Yes, I think at least for the moment it should work fine this way.
> Eventually, I'd like to integrate it with --export (and associated QMP
> commands, which are still to be created), too. Maybe at that point we
> want to make the QOM object not user creatable any more.
>
> Would it make sense to prefix the object type name with "x-" so we can
> later retire it from the external user interface without a deprecation
> period?
>
> As for test cases, do you think it would be hard to just modify the
> tests to send an explicit 'quit' command to the daemon?
>
> > I'm curious when will be formal version of qemu-storage-daemon
> > finished so I can take advantage of it? Or should I apply the RFC
> > PATCHes to my working branch directly and submit them together with
> > the patches on vhost-user-blk server feature when posting v3?
>
> It's the next thing I'm planning to work on after completing the
> coroutine-base QMP handlers (which I hope to get finished very soon).
>
> For the time being I would suggest that you put any patches that depend
> on qemu-storage-daemon (if you do need it) at the end of your series so
> that we could apply the first part even if the storage daemon isn't in
> yet.
>
> The latest version of my patches is at:
>
>     git://repo.or.cz/qemu/kevin.git storage-daemon
>
> But if you just need something for testing your code, I think it would
> even make sense if you kept your standalone tool around (even though
> we'll never merge it) and we'll deal with integration in the storage
> daemon once both parts are ready.
>
> Kevin
>


-- 
Best regards,
Coiby