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4ce385f564
Recently _pgd_alloc() was switched from using __get_free_pages() to
pagetable_alloc_noprof(), which might return a compound page in case
the allocation order is larger than 0.
On x86 this will be the case if CONFIG_MITIGATION_PAGE_TABLE_ISOLATION
is set, even if PTI has been disabled at runtime.
When running as a Xen PV guest (this will always disable PTI), using
a compound page for a PGD will result in VM_BUG_ON_PGFLAGS being
triggered when the Xen code tries to pin the PGD.
Fix the Xen issue together with the not needed 8k allocation for a
PGD with PTI disabled by replacing PGD_ALLOCATION_ORDER with an
inline helper returning the needed order for PGD allocations.
Fixes: a9b3c355c2 ("asm-generic: pgalloc: provide generic __pgd_{alloc,free}")
Reported-by: Petr Vaněk <arkamar@atlas.cz>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Tested-by: Petr Vaněk <arkamar@atlas.cz>
Cc:stable@vger.kernel.org
Link: https://lore.kernel.org/all/20250422131717.25724-1-jgross%40suse.com
161 lines
4.8 KiB
C
161 lines
4.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_X86_PGALLOC_H
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#define _ASM_X86_PGALLOC_H
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#include <linux/threads.h>
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#include <linux/mm.h> /* for struct page */
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#include <linux/pagemap.h>
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#include <asm/cpufeature.h>
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#define __HAVE_ARCH_PTE_ALLOC_ONE
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#define __HAVE_ARCH_PGD_FREE
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#include <asm-generic/pgalloc.h>
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static inline int __paravirt_pgd_alloc(struct mm_struct *mm) { return 0; }
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#ifdef CONFIG_PARAVIRT_XXL
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#include <asm/paravirt.h>
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#else
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#define paravirt_pgd_alloc(mm) __paravirt_pgd_alloc(mm)
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static inline void paravirt_pgd_free(struct mm_struct *mm, pgd_t *pgd) {}
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static inline void paravirt_alloc_pte(struct mm_struct *mm, unsigned long pfn) {}
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static inline void paravirt_alloc_pmd(struct mm_struct *mm, unsigned long pfn) {}
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static inline void paravirt_alloc_pmd_clone(unsigned long pfn, unsigned long clonepfn,
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unsigned long start, unsigned long count) {}
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static inline void paravirt_alloc_pud(struct mm_struct *mm, unsigned long pfn) {}
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static inline void paravirt_alloc_p4d(struct mm_struct *mm, unsigned long pfn) {}
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static inline void paravirt_release_pte(unsigned long pfn) {}
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static inline void paravirt_release_pmd(unsigned long pfn) {}
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static inline void paravirt_release_pud(unsigned long pfn) {}
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static inline void paravirt_release_p4d(unsigned long pfn) {}
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#endif
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/*
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* In case of Page Table Isolation active, we acquire two PGDs instead of one.
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* Being order-1, it is both 8k in size and 8k-aligned. That lets us just
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* flip bit 12 in a pointer to swap between the two 4k halves.
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*/
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static inline unsigned int pgd_allocation_order(void)
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{
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if (cpu_feature_enabled(X86_FEATURE_PTI))
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return 1;
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return 0;
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}
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/*
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* Allocate and free page tables.
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*/
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extern pgd_t *pgd_alloc(struct mm_struct *);
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extern void pgd_free(struct mm_struct *mm, pgd_t *pgd);
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extern pgtable_t pte_alloc_one(struct mm_struct *);
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extern void ___pte_free_tlb(struct mmu_gather *tlb, struct page *pte);
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static inline void __pte_free_tlb(struct mmu_gather *tlb, struct page *pte,
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unsigned long address)
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{
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___pte_free_tlb(tlb, pte);
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}
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static inline void pmd_populate_kernel(struct mm_struct *mm,
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pmd_t *pmd, pte_t *pte)
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{
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paravirt_alloc_pte(mm, __pa(pte) >> PAGE_SHIFT);
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set_pmd(pmd, __pmd(__pa(pte) | _PAGE_TABLE));
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}
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static inline void pmd_populate_kernel_safe(struct mm_struct *mm,
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pmd_t *pmd, pte_t *pte)
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{
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paravirt_alloc_pte(mm, __pa(pte) >> PAGE_SHIFT);
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set_pmd_safe(pmd, __pmd(__pa(pte) | _PAGE_TABLE));
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}
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static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
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struct page *pte)
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{
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unsigned long pfn = page_to_pfn(pte);
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paravirt_alloc_pte(mm, pfn);
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set_pmd(pmd, __pmd(((pteval_t)pfn << PAGE_SHIFT) | _PAGE_TABLE));
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}
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#if CONFIG_PGTABLE_LEVELS > 2
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extern void ___pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd);
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static inline void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd,
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unsigned long address)
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{
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___pmd_free_tlb(tlb, pmd);
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}
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#ifdef CONFIG_X86_PAE
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extern void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmd);
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#else /* !CONFIG_X86_PAE */
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static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd)
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{
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paravirt_alloc_pmd(mm, __pa(pmd) >> PAGE_SHIFT);
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set_pud(pud, __pud(_PAGE_TABLE | __pa(pmd)));
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}
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static inline void pud_populate_safe(struct mm_struct *mm, pud_t *pud, pmd_t *pmd)
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{
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paravirt_alloc_pmd(mm, __pa(pmd) >> PAGE_SHIFT);
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set_pud_safe(pud, __pud(_PAGE_TABLE | __pa(pmd)));
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}
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#endif /* CONFIG_X86_PAE */
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#if CONFIG_PGTABLE_LEVELS > 3
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static inline void p4d_populate(struct mm_struct *mm, p4d_t *p4d, pud_t *pud)
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{
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paravirt_alloc_pud(mm, __pa(pud) >> PAGE_SHIFT);
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set_p4d(p4d, __p4d(_PAGE_TABLE | __pa(pud)));
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}
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static inline void p4d_populate_safe(struct mm_struct *mm, p4d_t *p4d, pud_t *pud)
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{
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paravirt_alloc_pud(mm, __pa(pud) >> PAGE_SHIFT);
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set_p4d_safe(p4d, __p4d(_PAGE_TABLE | __pa(pud)));
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}
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extern void ___pud_free_tlb(struct mmu_gather *tlb, pud_t *pud);
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static inline void __pud_free_tlb(struct mmu_gather *tlb, pud_t *pud,
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unsigned long address)
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{
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___pud_free_tlb(tlb, pud);
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}
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#if CONFIG_PGTABLE_LEVELS > 4
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static inline void pgd_populate(struct mm_struct *mm, pgd_t *pgd, p4d_t *p4d)
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{
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if (!pgtable_l5_enabled())
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return;
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paravirt_alloc_p4d(mm, __pa(p4d) >> PAGE_SHIFT);
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set_pgd(pgd, __pgd(_PAGE_TABLE | __pa(p4d)));
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}
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static inline void pgd_populate_safe(struct mm_struct *mm, pgd_t *pgd, p4d_t *p4d)
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{
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if (!pgtable_l5_enabled())
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return;
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paravirt_alloc_p4d(mm, __pa(p4d) >> PAGE_SHIFT);
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set_pgd_safe(pgd, __pgd(_PAGE_TABLE | __pa(p4d)));
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}
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extern void ___p4d_free_tlb(struct mmu_gather *tlb, p4d_t *p4d);
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static inline void __p4d_free_tlb(struct mmu_gather *tlb, p4d_t *p4d,
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unsigned long address)
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{
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if (pgtable_l5_enabled())
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___p4d_free_tlb(tlb, p4d);
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}
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#endif /* CONFIG_PGTABLE_LEVELS > 4 */
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#endif /* CONFIG_PGTABLE_LEVELS > 3 */
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#endif /* CONFIG_PGTABLE_LEVELS > 2 */
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#endif /* _ASM_X86_PGALLOC_H */
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