Re: [Qemu-devel] [PATCH v2 1/4] hostmem-memfd: disable for systems wihtout sealing support

[Eduardo Habkost <ehabkost@redhat.com>]

On Wed, Dec 12, 2018 at 07:49:36AM +0100, Gerd Hoffmann wrote:
> On Tue, Dec 11, 2018 at 02:09:11PM +0300, Ilya Maximets wrote:
> > On 11.12.2018 13:53, Daniel P. Berrangé wrote:
> > >>
> > >> Let's restrict memfd backend to systems with sealing support.
> > > 
> > > I don't think we need todo that - sealing is optional in the QEMU code,
> > > we simply have it set to the wrong default when sealing is not available.
> > 
> > That was literally what I've fixed in v1:
> >     https://lists.nongnu.org/archive/html/qemu-devel/2018-11/msg05483.html
> > 
> > but 2 people suggested me to disable memfd entirely for this case.
> > Do you think I need to get patch from v1 back ?
> > 
> > Gerd, Marc-André, what do you think?
> 
> I still think it makes sense to require sealing support.  Sealing is
> very useful, and there are only a few kernel versions with memfd but
> without sealing.  So finding such kernels in the wild will become more
> rare over time.  I wouldn't worry too much about them.

-object memory-backend-memfd,id=mem,size=2M,seal=off still
works on those systems, doesn't it?  What's the rationale for
breaking a working configuration without following the
deprecation policy?

-- 
Eduardo