From mboxrd@z Thu Jan  1 00:00:00 1970
From: Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
Subject: Re: [PATCH] x86/efi: Always map boot service regions into new EFI
 page tables
Date: Mon, 14 Mar 2016 11:35:02 +0000
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To: Ingo Molnar <mingo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: Scott Ashcroft <scott.ashcroft-qw6QB7/foO7QT0dZR+AlfA@public.gmane.org>, "H . Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>, Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>, Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Maarten Lankhorst <maarten.lankhorst-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>, Matthew Garrett <mjg59-1xO5oi07KQx4cg9Nei1l7Q@public.gmane.org>, Borislav Petkov <bp-Gina5bIWoIWzQB+pC5nmwQ@public.gmane.org>, Ben Hutchings <ben-/+tVBieCtBitmTQ+vhA3Yw@public.gmane.org>, Raphael Hertzog <hertzog-8fiUuRrzOP0dnm+yROfE0A@public.gmane.org>, Roger Shimizu <rogershimizu-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, Alexis Murzeau <amurzeau-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
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On Mon, 14 Mar, at 11:30:19AM, Ingo Molnar wrote:
> 
> * Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org> wrote:
> 
> > diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
> > index 8fee5b6f8f66..af74849e8c0f 100644
> > --- a/arch/x86/mm/pageattr.c
> > +++ b/arch/x86/mm/pageattr.c
> > @@ -1055,7 +1055,7 @@ static int populate_pud(struct cpa_data *cpa, unsigned long start, pgd_t *pgd,
> >  	/*
> >  	 * Map everything starting from the Gb boundary, possibly with 1G pages
> >  	 */
> > -	while (end - start >= PUD_SIZE) {
> > +	while (cpu_has_gbpages && end - start >= PUD_SIZE) {
> >  		set_pud(pud, __pud(cpa->pfn << PAGE_SHIFT | _PAGE_PSE |
> >  				   massage_pgprot(pud_pgprot)));
> 
> Btw., can 'cpa->pfn << PAGE_SHIFT' possibly work on 32-bit systems?
> 
> cpa->pfn is unsigned long, so the result gets truncated to 32 bits ...
> 
> cpa->pfn should be u64.

That is a nice catch.

Note that we never run this code on 32-bit right now. Moving 32-bit to
this code and away from the old_map scheme is on my TODO list.