Re: [PATCH] microvm: turn off io reservations for pcie root ports

[Gerd Hoffmann]

On Wed, Jun 29, 2022 at 03:16:17AM -0400, Michael S. Tsirkin wrote:
> On Wed, Jun 29, 2022 at 09:10:23AM +0200, Gerd Hoffmann wrote:
> > On Mon, Jun 27, 2022 at 06:37:50PM -0400, Michael S. Tsirkin wrote:
> > > On Thu, Jun 09, 2022 at 09:28:38AM +0200, Gerd Hoffmann wrote:
> > > > On Wed, Jun 08, 2022 at 12:06:17PM -0400, Michael S. Tsirkin wrote:
> > > > > On Fri, Jun 03, 2022 at 10:59:20AM +0200, Gerd Hoffmann wrote:
> > > > > > The pcie host bridge has no io window on microvm,
> > > > > > so io reservations will not work.
> > > > > > 
> > > > > > Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> > > > > 
> > > > > I don't much like overriding user like this. We end up users
> > > > > setting it to silly values and then if we do want to
> > > > > support this things just break. Thoughts?
> > > > 
> > > > Well, it just looked like the simplest way to tell the firmware that
> > > > io reservations are pointless.  Do you have a better idea?
> > > > 
> > > > take care,
> > > >   Gerd
> > > 
> > > Fail if user supplies values we can't support.
> > 
> > Well, it is the *default* value which doesn't work on microvm.
> > 
> > take care,
> >   Gerd
> 
> Changing defaults is ok of course. Let's just not override the user.

Ok, so I could use a compat property instead and change the default
for microvm that way.  That would allow the user set any value it
wants.

I still don't see the point though.  There is only a single value which
makes sense on microvm.  Which is zero.  The only effect the user could
archive is make the firmware throwing errors ...

take care,
  Gerd