Re: [PATCH v6 6/7] tools: add example application to initialize dom0less PV drivers

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Wed, 11 May 2022, Julien Grall wrote:
> > +    rc = xs_introduce_domain(xsh, info->domid,
> > +            (GUEST_MAGIC_BASE >> XC_PAGE_SHIFT) + XENSTORE_PFN_OFFSET,
> > +            xenstore_evtchn);
> 
> I might be missing something here. In an ealier version, I pointed out that
> xs_introduce_domain() would fail in the case the dom0less domain doesn't have
> "xen,enhanced".
> 
> AFAICT, you agreed that the (part?) of initialization should be skipped. But I
> don't see the change in the code. Regarding the placement, we could either
> fully skip init_domain() or just xs_introduce_domain(). The latter might be
> better so all the domains are listed using xenstore-ls.
> 
> So something like below should work:
> 
> if ( xenstore_evtchn )
> {
>     rc = xs_introduce...();
>     ...
> }

Yes, good point. xenstore_evtchn could be zero validly (first evtchn is
zero), so instead I'll check on xenstore_pfn to be zero (xenstore_pfn is
0 for non-enhanced domUs.)