Re: [Qemu-devel] [PATCH RFC] vfio-ap: flag as compatible with balloon

[Cornelia Huck <cohuck@redhat.com>]

On Fri, 7 Dec 2018 13:52:53 +0100
Halil Pasic <pasic@linux.ibm.com> wrote:

> On Fri, 7 Dec 2018 13:29:46 +0100
> Cornelia Huck <cohuck@redhat.com> wrote:
> 
> > On Fri, 7 Dec 2018 13:17:02 +0100
> > Christian Borntraeger <borntraeger@de.ibm.com> wrote:
> >   
> > > On 05.12.2018 15:51, Cornelia Huck wrote:  
> > > > vfio-ap devices do not pin any pages in the host. Therefore, they
> > > > are belived to be compatible with memory ballooning.
> > > > 
> > > > Flag them as compatible, so both vfio-ap and a balloon can be
> > > > used simultaneously.
> > > > 
> > > > Signed-off-by: Cornelia Huck <cohuck@redhat.com>    
> 
> With the comment stuff sorted out:
> Reviewed-by: Halil Pasic <pasic@linux.ibm.com> 

So, do you agree with the comment change I suggested?

+    /*
+     * vfio-ap devices operate in a way compatible with
+     * memory ballooning, as no pages are pinned in the host.
+     * This needs to be set before vfio_get_device() for vfio common to
+     * handle the balloon inhibitor.
+     */

> 
> @Connie: Just had a look at the MAINTAINERS file and hw/vfio/ap.c
> is listed under Arch. support S90 with you as a maintainer, and under
> vfio-ap with 4 maintainers listed one of them being me. The question
> is who is going to post a PULL request for this?

General practice has been that I'm collecting everything s390x related.
I have also pulled from others before (e.g. some bios changes from
Thomas). While you could apply the patch, send it to me, and then I'd
queue it to s390-next, I can also simply queue it directly with your
ack :)

[Longer term, if you want to collect ap patches and then send me a pull
request, I would also be happy to do that. For this single patch, it
seems overkill.]

> 
> > > 
> > > Does it make sense to add cc stable for 3.1?  
> > 
> > Can do that, given that s390x systems really rely on the ballooner in
> > general.
> >   
> 
> I agree with cc stable.

Will add when applying.