Re: [PATCH v6 13/15] x86/mm: drop old page table APIs

[Hongyan Xia <hx242@xxxxxxx>]

On Wed, 2020-05-20 at 12:09 +0200, Jan Beulich wrote:
> On 24.04.2020 16:09, Hongyan Xia wrote:
> > --- a/xen/arch/x86/smpboot.c
> > +++ b/xen/arch/x86/smpboot.c
> > @@ -815,7 +815,7 @@ static int setup_cpu_root_pgt(unsigned int cpu)
> >      if ( !opt_xpti_hwdom && !opt_xpti_domu )
> >          return 0;
> >  
> > -    rpt = alloc_xen_pagetable();
> > +    rpt = alloc_xenheap_page();
> 
> So the idea of not using alloc_domheap_page() +
> map_domain_page_global()
> here is that in the long run alloc_xenheap_page() will resolve to
> just
> this? If so, while I'd have preferred the greater flexibility until
> then,
> this is fair enough, i.e.
> Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>

alloc_xenheap_page() has an advantage which is the fast PA->VA lookup,
which is currently required by the restore_all_guest logic. If we
change how restore_all_guest works or gain fast PA->VA lookup for
globally mapped pages, then xenheap could probably just be removed.

Hongyan