Re: [patch 34/60] x86/mm/kpti: Populate user PGD

From: Borislav Petkov
Date: Tue Dec 05 2017 - 14:18:09 EST


On Mon, Dec 04, 2017 at 03:07:40PM +0100, Thomas Gleixner wrote:
> From: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
>
> Populate the PGD entries in the init user PGD which cover the kernel half
> of the address space. This makes sure that the installment of the user
> visible kernel mappings finds a populated PGD.
>
> In clone_pgd_range() copy the init user PGDs which cover the kernel half of
> the address space, so a process has all the required kernel mappings
> visible.
>
> [ tglx: Split out from the big kaiser dump ]
>
> Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>
> ---
> arch/x86/include/asm/pgtable.h | 5 +++++
> arch/x86/mm/kpti.c | 41 +++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 46 insertions(+)

Reviewed-by: Borislav Petkov <bp@xxxxxxx>

--
Regards/Gruss,
Boris.

SUSE Linux GmbH, GF: Felix ImendÃrffer, Jane Smithard, Graham Norton, HRB 21284 (AG NÃrnberg)
--