Thread (47 messages) 47 messages, 6 authors, 2023-06-08

[PATCH v3 15/34] x86: Convert various functions to use ptdescs

From: Vishal Moola (Oracle) <hidden>
Date: 2023-05-31 22:44:16
Also in: kvm, linux-arch, linux-arm-kernel, linux-m68k, linux-mips, linux-riscv, linux-s390, linux-sh, linux-um, loongarch, sparclinux, xen-devel
Subsystem: the rest, x86 architecture (32-bit and 64-bit), x86 mm · Maintainers: Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, Andy Lutomirski, Peter Zijlstra

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
these to use pagetable_alloc() and ptdesc_address() instead to help
standardize page tables further.

Signed-off-by: Vishal Moola (Oracle) <redacted>
---
 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 e4f499eb0f29..79681557fce6 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 = (pmd_t *)ptdesc_address(ptdesc);
+		}
+
 		pmds[i] = pmd;
 	}
 
@@ -838,7 +846,7 @@ 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
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