On Mon, Jun 12, 2023 at 02:04:04PM -0700, Vishal Moola (Oracle) wrote:
> In order to split struct ptdesc from struct page, convert various
> functions to use ptdescs.
>
> Some of the functions use the *get*page*() helper functions. Convert
Nit: *get_free_page*()
> these to use pagetable_alloc() and ptdesc_address() instead to help
> standardize page tables further.
More importantly, get_free_pages() ensures a page won't be allocated from
HIGHMEM, and for 32-bits this is a must.
> Signed-off-by: Vishal Moola (Oracle) <vishal.moola@xxxxxxxxx>
> ---
> arch/x86/mm/pgtable.c | 46 +++++++++++++++++++++++++------------------
> 1 file changed, 27 insertions(+), 19 deletions(-)
>
> diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
> index 15a8009a4480..6da7fd5d4782 100644
> --- a/arch/x86/mm/pgtable.c
> +++ b/arch/x86/mm/pgtable.c
> @@ -52,7 +52,7 @@ early_param("userpte", setup_userpte);
>
> void ___pte_free_tlb(struct mmu_gather *tlb, struct page *pte)
> {
> - pgtable_pte_page_dtor(pte);
> + pagetable_pte_dtor(page_ptdesc(pte));
> paravirt_release_pte(page_to_pfn(pte));
> paravirt_tlb_remove_table(tlb, pte);
> }
> @@ -60,7 +60,7 @@ void ___pte_free_tlb(struct mmu_gather *tlb, struct page *pte)
> #if CONFIG_PGTABLE_LEVELS > 2
> void ___pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd)
> {
> - struct page *page = virt_to_page(pmd);
> + struct ptdesc *ptdesc = virt_to_ptdesc(pmd);
> paravirt_release_pmd(__pa(pmd) >> PAGE_SHIFT);
> /*
> * NOTE! For PAE, any changes to the top page-directory-pointer-table
> @@ -69,8 +69,8 @@ void ___pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd)
> #ifdef CONFIG_X86_PAE
> tlb->need_flush_all = 1;
> #endif
> - pgtable_pmd_page_dtor(page);
> - paravirt_tlb_remove_table(tlb, page);
> + pagetable_pmd_dtor(ptdesc);
> + paravirt_tlb_remove_table(tlb, ptdesc_page(ptdesc));
> }
>
> #if CONFIG_PGTABLE_LEVELS > 3
> @@ -92,16 +92,16 @@ void ___p4d_free_tlb(struct mmu_gather *tlb, p4d_t *p4d)
>
> static inline void pgd_list_add(pgd_t *pgd)
> {
> - struct page *page = virt_to_page(pgd);
> + struct ptdesc *ptdesc = virt_to_ptdesc(pgd);
>
> - list_add(&page->lru, &pgd_list);
> + list_add(&ptdesc->pt_list, &pgd_list);
> }
>
> static inline void pgd_list_del(pgd_t *pgd)
> {
> - struct page *page = virt_to_page(pgd);
> + struct ptdesc *ptdesc = virt_to_ptdesc(pgd);
>
> - list_del(&page->lru);
> + list_del(&ptdesc->pt_list);
> }
>
> #define UNSHARED_PTRS_PER_PGD \
> @@ -112,12 +112,12 @@ static inline void pgd_list_del(pgd_t *pgd)
>
> static void pgd_set_mm(pgd_t *pgd, struct mm_struct *mm)
> {
> - virt_to_page(pgd)->pt_mm = mm;
> + virt_to_ptdesc(pgd)->pt_mm = mm;
> }
>
> struct mm_struct *pgd_page_get_mm(struct page *page)
> {
> - return page->pt_mm;
> + return page_ptdesc(page)->pt_mm;
> }
>
> static void pgd_ctor(struct mm_struct *mm, pgd_t *pgd)
> @@ -213,11 +213,14 @@ void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmd)
> static void free_pmds(struct mm_struct *mm, pmd_t *pmds[], int count)
> {
> int i;
> + struct ptdesc *ptdesc;
>
> for (i = 0; i < count; i++)
> if (pmds[i]) {
> - pgtable_pmd_page_dtor(virt_to_page(pmds[i]));
> - free_page((unsigned long)pmds[i]);
> + ptdesc = virt_to_ptdesc(pmds[i]);
> +
> + pagetable_pmd_dtor(ptdesc);
> + pagetable_free(ptdesc);
> mm_dec_nr_pmds(mm);
> }
> }
> @@ -232,16 +235,21 @@ static int preallocate_pmds(struct mm_struct *mm, pmd_t *pmds[], int count)
> gfp &= ~__GFP_ACCOUNT;
>
> for (i = 0; i < count; i++) {
> - pmd_t *pmd = (pmd_t *)__get_free_page(gfp);
> - if (!pmd)
> + pmd_t *pmd = NULL;
> + struct ptdesc *ptdesc = pagetable_alloc(gfp, 0);
> +
> + if (!ptdesc)
> failed = true;
> - if (pmd && !pgtable_pmd_page_ctor(virt_to_page(pmd))) {
> - free_page((unsigned long)pmd);
> - pmd = NULL;
> + if (ptdesc && !pagetable_pmd_ctor(ptdesc)) {
> + pagetable_free(ptdesc);
> + ptdesc = NULL;
> failed = true;
> }
> - if (pmd)
> + if (ptdesc) {
> mm_inc_nr_pmds(mm);
> + pmd = ptdesc_address(ptdesc);
> + }
> +
> pmds[i] = pmd;
> }
>
> @@ -830,7 +838,7 @@ int pud_free_pmd_page(pud_t *pud, unsigned long addr)
>
> free_page((unsigned long)pmd_sv);
>
> - pgtable_pmd_page_dtor(virt_to_page(pmd));
> + pagetable_pmd_dtor(virt_to_ptdesc(pmd));
> free_page((unsigned long)pmd);
>
> return 1;
> --
> 2.40.1
>
>
--
Sincerely yours,
Mike.
