Re: [PATCH v6 4/7] xen/arm: configure dom0less domain for enabling xenstore after boot

[Julien Grall <julien@xxxxxxx>]

Hi Bertrand,

On 11/05/2022 08:46, Bertrand Marquis wrote:
> > On 10 May 2022, at 17:35, Julien Grall <julien@xxxxxxx> wrote:
> >
> > Hi Rahul,
> >
> > On 10/05/2022 17:30, Rahul Singh wrote:
> > > > +    rc = evtchn_alloc_unbound(&alloc);
> > > > +    if ( rc )
> > > > +    {
> > > > +        printk("Failed allocating event channel for domain\n");
> > > > +        return rc;
> > > > +    }
> > > > +
> > > > +    d->arch.hvm.params[HVM_PARAM_STORE_EVTCHN] = alloc.port;
> > > > +
> > > > +    return 0;
> > > > +}
> > > > +
> > > > static int __init construct_domU(struct domain *d,
> > > >                                   const struct dt_device_node *node)
> > > > {
> > > > @@ -3214,6 +3243,14 @@ static int __init construct_domU(struct domain *d,
> > > >      if ( rc < 0 )
> > > >          return rc;
> > > >
> > > > +    if ( kinfo.dom0less_enhanced )
> > > I think we need to do something like this to fix the error.
> > >   if ( hardware_domain && kinfo.dom0less_enhanced )
> > > {
> > > }
> > Is there any use case to use "dom0less_enhanced" without dom0 (or a domain 
> > servicing Xenstored)?
> Just being curious here but would it even be possible to have non dom0 domain 
> servicing xenstored ?
You can build Xenstored against mini-os and configure the init script to 
launch xenstored as a domain.
> > If not, then I would consider to forbid this case and return an error.
> One way or an other we need to solve the crash but if it is forbidden we must 
> prevent coming to this step earlier as it means the configuration is wrong.
I think this should be checked when parsing the configuration.

Cheers,

--
Julien Grall