On 02/12/24 at 12:44pm, Kirill A. Shutemov wrote:
> lookup_address() only returns correct page table level for the entry if
> the entry is not none.
>
> Make the helper to always return correct 'level'. It allows to implement
> iterator over kernel page tables using lookup_address().
>
> Add one more entry into enum pg_level to indicate size of VA covered by
> one PGD entry in 5-level paging mode.
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> Reviewed-by: Rick Edgecombe <rick.p.edgecombe@xxxxxxxxx>
> ---
> arch/x86/include/asm/pgtable_types.h | 1 +
> arch/x86/mm/pat/set_memory.c | 8 ++++----
> 2 files changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
> index 0b748ee16b3d..3f648ffdfbe5 100644
> --- a/arch/x86/include/asm/pgtable_types.h
> +++ b/arch/x86/include/asm/pgtable_types.h
> @@ -548,6 +548,7 @@ enum pg_level {
> PG_LEVEL_2M,
> PG_LEVEL_1G,
> PG_LEVEL_512G,
> + PG_LEVEL_256T,
> PG_LEVEL_NUM
> };
>
> diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
> index f92da8c9a86d..3612e3167147 100644
> --- a/arch/x86/mm/pat/set_memory.c
> +++ b/arch/x86/mm/pat/set_memory.c
> @@ -666,32 +666,32 @@ pte_t *lookup_address_in_pgd(pgd_t *pgd, unsigned long address,
LGTM,
Reviewed-by: Baoquan He <bhe@xxxxxxxxxx>
By the way, we may need update the code comment above function
lookup_address_in_pgd() and function lookup_address() since they don't
reflect the latest behaviour of them.
> pud_t *pud;
> pmd_t *pmd;
>
> - *level = PG_LEVEL_NONE;
> + *level = PG_LEVEL_256T;
>
> if (pgd_none(*pgd))
> return NULL;
>
> + *level = PG_LEVEL_512G;
> p4d = p4d_offset(pgd, address);
> if (p4d_none(*p4d))
> return NULL;
>
> - *level = PG_LEVEL_512G;
> if (p4d_large(*p4d) || !p4d_present(*p4d))
> return (pte_t *)p4d;
>
> + *level = PG_LEVEL_1G;
> pud = pud_offset(p4d, address);
> if (pud_none(*pud))
> return NULL;
>
> - *level = PG_LEVEL_1G;
> if (pud_large(*pud) || !pud_present(*pud))
> return (pte_t *)pud;
>
> + *level = PG_LEVEL_2M;
> pmd = pmd_offset(pud, address);
> if (pmd_none(*pmd))
> return NULL;
>
> - *level = PG_LEVEL_2M;
> if (pmd_large(*pmd) || !pmd_present(*pmd))
> return (pte_t *)pmd;
>
> --
> 2.43.0
>
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