On 09/07/2018, 11:10 AM, Jiri Slaby wrote:
> From: Andi Kleen <ak@xxxxxxxxxxxxxxx>
forgot to --reset-author, scratch this.
> Mostly recycling the commit log from adaba23ccd7d which fixed
> populate_pmd, but did not fix populate_pud. The same problem exists
> there.
>
> Stable trees reverted the following patch:
> Revert "x86/mm/pat: Ensure cpa->pfn only contains page frame numbers"
>
> This reverts commit 87e2bd898d3a79a8c609f183180adac47879a2a4 which is
> commit edc3b9129cecd0f0857112136f5b8b1bc1d45918 upstream.
>
> but the L1TF patch 02ff2769edbc backported here
>
> x86/mm/pat: Make set_memory_np() L1TF safe
>
> commit 958f79b9ee55dfaf00c8106ed1c22a2919e0028b upstream
>
> set_memory_np() is used to mark kernel mappings not present, but it has
> it's own open coded mechanism which does not have the L1TF protection of
> inverting the address bits.
>
> assumed that cpa->pfn contains a PFN. With the above patch reverted
> it does not, which causes the PUD to be set to an incorrect address
> shifted by 12 bits, which can cause various failures.
>
> Convert the address to a PFN before passing it to pud_pfn().
>
> This is a 4.4 stable only patch to fix the L1TF patches backport there.
>
> Cc: stable@xxxxxxxxxxxxxxx # 4.4-only
> Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
> ---
> arch/x86/mm/pageattr.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
> index 1007fa80f5a6..0e1dd7d47f05 100644
> --- a/arch/x86/mm/pageattr.c
> +++ b/arch/x86/mm/pageattr.c
> @@ -1079,7 +1079,7 @@ 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) {
> - set_pud(pud, pud_mkhuge(pfn_pud(cpa->pfn,
> + set_pud(pud, pud_mkhuge(pfn_pud(cpa->pfn >> PAGE_SHIFT,
> canon_pgprot(pud_pgprot))));
>
> start += PUD_SIZE;
>
--
js
suse labs
