Re: [PATCH 1/3] x86, mm: Include the entire kernel memory map intrampoline_pgd

[H. Peter Anvin]

On 10/03/2012 06:31 AM, Jan Beulich wrote:
> > > > Matt Fleming <matt@xxxxxxxxxxxxxxxxx> 10/03/12 2:59 PM >>>
> > +static int insert_identity_mapping(resource_size_t paddr, unsigned long vaddr,
> > +                    unsigned long size)
> > +{
> > +    unsigned long end = vaddr + size;
> > +    unsigned long next;
> > +    pgd_t *vpgd, *ppgd;
> > +
> > +#ifdef CONFIG_X86_32
> > +    ppgd = initial_page_table + pgd_index(paddr);
> > +
> > +    if (paddr >= PAGE_OFFSET || paddr + size > PAGE_OFFSET)
> > +        return 1;
> > +#else
> > +    ppgd = __va(real_mode_header->trampoline_pgd) + pgd_index(paddr);
>
> Missing equivalent code (to the 32-bit one above) here - after all, you're trying
> to potentially insert a 52-bit physical address into 48-bit virtual space.

We should have the check, but at least for Linux support we require
P <= V-2.

	-hpa


--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

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