Re: [PATCH v2 4/4] libxc/arm: allocate xenstore and console pages

From: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
To: Tim Deegan <tim@xen.org>
Cc: "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>,
	Ian Campbell <Ian.Campbell@citrix.com>,
	Stefano Stabellini <Stefano.Stabellini@eu.citrix.com>
Subject: Re: [PATCH v2 4/4] libxc/arm: allocate xenstore and console pages
Date: Fri, 13 Jul 2012 16:32:52 +0100	[thread overview]
Message-ID: <alpine.DEB.2.02.1207131628350.23783@kaball.uk.xensource.com> (raw)
In-Reply-To: <20120712114626.GD89265@ocelot.phlegethon.org>

On Thu, 12 Jul 2012, Tim Deegan wrote:
> At 11:55 +0100 on 04 Jul (1341402949), Stefano Stabellini wrote:
> >  static int alloc_magic_pages(struct xc_dom_image *dom)
> >  {
> > +    int rc, i, allocsz;
> > +    xen_pfn_t store_pfn, console_pfn, p2m[NR_MAGIC_PAGES];
> > +
> >      DOMPRINTF_CALLED(dom->xch);
> > -    /* XXX
> > -     *   dom->p2m_guest
> > -     *   dom->start_info_pfn
> > -     *   dom->xenstore_pfn
> > -     *   dom->console_pfn
> > -     */
> > +
> > +    for (i = 0; i < NR_MAGIC_PAGES; i++)
> > +        p2m[i] = dom->rambase_pfn + dom->total_pages + i;
> > +
> > +    for ( i = rc = allocsz = 0;
> > +          (i < NR_MAGIC_PAGES) && !rc;
> > +          i += allocsz) {
> > +        allocsz = NR_MAGIC_PAGES - i;
> > +        rc = xc_domain_populate_physmap_exact(
> > +                dom->xch, dom->guest_domid, allocsz,
> > +                0, 0, &p2m[i]);
> > +    }
> 
> What does this loop do?  It seems like it can only ever execute once.

I think that you are right.
In that case also the same loop in arch_setup_meminit in Ian's patch
should probably be removed:

http://marc.info/?l=xen-devel&m=134089793916569