Re: [XEN PATCH v2 2/5] xen: export get_free_port

[Julien Grall <julien@xxxxxxx>]

Hi,

On 26/01/2022 07:30, Jan Beulich wrote:
> On 26.01.2022 02:03, Stefano Stabellini wrote:
> > Are you guys OK with something like this?
> With proper proof that this isn't going to regress anything else, maybe.
That's why I sugested to also gate with system_state < SYS_STATE_boot so 
we reduce the potential regression (the use of hypercall should be 
limited at boot).
FWIW, there was a thread [1] to discuss the same issue as Stefano is 
facing (but in the context of Live-Update).
> But ...
>
> > --- a/xen/include/xsm/dummy.h
> > +++ b/xen/include/xsm/dummy.h
> > @@ -92,7 +92,9 @@ static always_inline int xsm_default_action(
> >               return 0;
> >           /* fall through */
> >       case XSM_PRIV:
> > -        if ( is_control_domain(src) )
> > +        if ( is_control_domain(src) ||
> > +             src->domain_id == DOMID_IDLE ||
> > +             src->domain_id == DOMID_XEN )
> >               return 0;
> ... my first question would be under what circumstances you might observe
> DOMID_XEN here and hence why this check is there.
>
> Jan >
[1] 
https://lore.kernel.org/xen-devel/bfd645cf42ef7786183be15c222ad04beed362c0.camel@xxxxxxx/
--
Julien Grall