Re: [PATCH v4 12/14] xen/arm64: mm: Introduce helpers to prepare/enable/disable the identity mapping

[Julien Grall <julien@xxxxxxx>]

Hi Michal,

On 16/01/2023 08:53, Michal Orzel wrote:
> On 13/01/2023 11:11, Julien Grall wrote:
> > +static void __init prepare_boot_identity_mapping(void)
> > +{
> > +    paddr_t id_addr = virt_to_maddr(_start);
> > +    lpae_t pte;
> > +    DECLARE_OFFSETS(id_offsets, id_addr);
> > +
> > +    /*
> > +     * We will be re-using the boot ID tables. They may not have been
> > +     * zeroed but they should be unlinked. So it is fine to use
> > +     * clear_page().
> > +     */
> > +    clear_page(boot_first_id);
> > +    clear_page(boot_second_id);
> > +    clear_page(boot_third_id);
> > +
> > +    if ( id_offsets[0] != 0 )
> > +        panic("Cannot handled ID mapping above 512GB\n");
> I might be lost but didn't we say before that we can load Xen in the first 2TB?
> Then, how does this check correspond to it?
I forgot to change the check after we decided to extend the reserved 
area from 512GB to 2TB. I will update it in the next version.
Cheers,

--
Julien Grall