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linux-next/include/linux/huge_mm.h
Sean Christopherson 005ba37cb8 mm: thp: KVM: Explicitly check for THP when populating secondary MMU
Add a helper, is_transparent_hugepage(), to explicitly check whether a
compound page is a THP and use it when populating KVM's secondary MMU.
The explicit check fixes a bug where a remapped compound page, e.g. for
an XDP Rx socket, is mapped into a KVM guest and is mistaken for a THP,
which results in KVM incorrectly creating a huge page in its secondary
MMU.

Fixes: 936a5fe6e6 ("thp: kvm mmu transparent hugepage support")
Reported-by: syzbot+c9d1fb51ac9d0d10c39d@syzkaller.appspotmail.com
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-01-27 20:00:01 +01:00

415 lines
12 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_HUGE_MM_H
#define _LINUX_HUGE_MM_H
#include <linux/sched/coredump.h>
#include <linux/mm_types.h>
#include <linux/fs.h> /* only for vma_is_dax() */
extern vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf);
extern int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,
pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr,
struct vm_area_struct *vma);
extern void huge_pmd_set_accessed(struct vm_fault *vmf, pmd_t orig_pmd);
extern int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm,
pud_t *dst_pud, pud_t *src_pud, unsigned long addr,
struct vm_area_struct *vma);
#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
extern void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud);
#else
static inline void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud)
{
}
#endif
extern vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd);
extern struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
unsigned long addr,
pmd_t *pmd,
unsigned int flags);
extern bool madvise_free_huge_pmd(struct mmu_gather *tlb,
struct vm_area_struct *vma,
pmd_t *pmd, unsigned long addr, unsigned long next);
extern int zap_huge_pmd(struct mmu_gather *tlb,
struct vm_area_struct *vma,
pmd_t *pmd, unsigned long addr);
extern int zap_huge_pud(struct mmu_gather *tlb,
struct vm_area_struct *vma,
pud_t *pud, unsigned long addr);
extern int mincore_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
unsigned long addr, unsigned long end,
unsigned char *vec);
extern bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr,
unsigned long new_addr, unsigned long old_end,
pmd_t *old_pmd, pmd_t *new_pmd);
extern int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
unsigned long addr, pgprot_t newprot,
int prot_numa);
vm_fault_t vmf_insert_pfn_pmd(struct vm_fault *vmf, pfn_t pfn, bool write);
vm_fault_t vmf_insert_pfn_pud(struct vm_fault *vmf, pfn_t pfn, bool write);
enum transparent_hugepage_flag {
TRANSPARENT_HUGEPAGE_FLAG,
TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG,
TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG,
TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG,
TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG,
TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG,
TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG,
#ifdef CONFIG_DEBUG_VM
TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG,
#endif
};
struct kobject;
struct kobj_attribute;
extern ssize_t single_hugepage_flag_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count,
enum transparent_hugepage_flag flag);
extern ssize_t single_hugepage_flag_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf,
enum transparent_hugepage_flag flag);
extern struct kobj_attribute shmem_enabled_attr;
#define HPAGE_PMD_ORDER (HPAGE_PMD_SHIFT-PAGE_SHIFT)
#define HPAGE_PMD_NR (1<<HPAGE_PMD_ORDER)
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
#define HPAGE_PMD_SHIFT PMD_SHIFT
#define HPAGE_PMD_SIZE ((1UL) << HPAGE_PMD_SHIFT)
#define HPAGE_PMD_MASK (~(HPAGE_PMD_SIZE - 1))
#define HPAGE_PUD_SHIFT PUD_SHIFT
#define HPAGE_PUD_SIZE ((1UL) << HPAGE_PUD_SHIFT)
#define HPAGE_PUD_MASK (~(HPAGE_PUD_SIZE - 1))
extern bool is_vma_temporary_stack(struct vm_area_struct *vma);
extern unsigned long transparent_hugepage_flags;
/*
* to be used on vmas which are known to support THP.
* Use transparent_hugepage_enabled otherwise
*/
static inline bool __transparent_hugepage_enabled(struct vm_area_struct *vma)
{
if (vma->vm_flags & VM_NOHUGEPAGE)
return false;
if (is_vma_temporary_stack(vma))
return false;
if (test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags))
return false;
if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_FLAG))
return true;
/*
* For dax vmas, try to always use hugepage mappings. If the kernel does
* not support hugepages, fsdax mappings will fallback to PAGE_SIZE
* mappings, and device-dax namespaces, that try to guarantee a given
* mapping size, will fail to enable
*/
if (vma_is_dax(vma))
return true;
if (transparent_hugepage_flags &
(1 << TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG))
return !!(vma->vm_flags & VM_HUGEPAGE);
return false;
}
bool transparent_hugepage_enabled(struct vm_area_struct *vma);
#define HPAGE_CACHE_INDEX_MASK (HPAGE_PMD_NR - 1)
static inline bool transhuge_vma_suitable(struct vm_area_struct *vma,
unsigned long haddr)
{
/* Don't have to check pgoff for anonymous vma */
if (!vma_is_anonymous(vma)) {
if (((vma->vm_start >> PAGE_SHIFT) & HPAGE_CACHE_INDEX_MASK) !=
(vma->vm_pgoff & HPAGE_CACHE_INDEX_MASK))
return false;
}
if (haddr < vma->vm_start || haddr + HPAGE_PMD_SIZE > vma->vm_end)
return false;
return true;
}
#define transparent_hugepage_use_zero_page() \
(transparent_hugepage_flags & \
(1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG))
#ifdef CONFIG_DEBUG_VM
#define transparent_hugepage_debug_cow() \
(transparent_hugepage_flags & \
(1<<TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG))
#else /* CONFIG_DEBUG_VM */
#define transparent_hugepage_debug_cow() 0
#endif /* CONFIG_DEBUG_VM */
extern unsigned long thp_get_unmapped_area(struct file *filp,
unsigned long addr, unsigned long len, unsigned long pgoff,
unsigned long flags);
extern void prep_transhuge_page(struct page *page);
extern void free_transhuge_page(struct page *page);
bool is_transparent_hugepage(struct page *page);
bool can_split_huge_page(struct page *page, int *pextra_pins);
int split_huge_page_to_list(struct page *page, struct list_head *list);
static inline int split_huge_page(struct page *page)
{
return split_huge_page_to_list(page, NULL);
}
void deferred_split_huge_page(struct page *page);
void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
unsigned long address, bool freeze, struct page *page);
#define split_huge_pmd(__vma, __pmd, __address) \
do { \
pmd_t *____pmd = (__pmd); \
if (is_swap_pmd(*____pmd) || pmd_trans_huge(*____pmd) \
|| pmd_devmap(*____pmd)) \
__split_huge_pmd(__vma, __pmd, __address, \
false, NULL); \
} while (0)
void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address,
bool freeze, struct page *page);
void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud,
unsigned long address);
#define split_huge_pud(__vma, __pud, __address) \
do { \
pud_t *____pud = (__pud); \
if (pud_trans_huge(*____pud) \
|| pud_devmap(*____pud)) \
__split_huge_pud(__vma, __pud, __address); \
} while (0)
extern int hugepage_madvise(struct vm_area_struct *vma,
unsigned long *vm_flags, int advice);
extern void vma_adjust_trans_huge(struct vm_area_struct *vma,
unsigned long start,
unsigned long end,
long adjust_next);
extern spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd,
struct vm_area_struct *vma);
extern spinlock_t *__pud_trans_huge_lock(pud_t *pud,
struct vm_area_struct *vma);
static inline int is_swap_pmd(pmd_t pmd)
{
return !pmd_none(pmd) && !pmd_present(pmd);
}
/* mmap_sem must be held on entry */
static inline spinlock_t *pmd_trans_huge_lock(pmd_t *pmd,
struct vm_area_struct *vma)
{
if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd))
return __pmd_trans_huge_lock(pmd, vma);
else
return NULL;
}
static inline spinlock_t *pud_trans_huge_lock(pud_t *pud,
struct vm_area_struct *vma)
{
if (pud_trans_huge(*pud) || pud_devmap(*pud))
return __pud_trans_huge_lock(pud, vma);
else
return NULL;
}
static inline int hpage_nr_pages(struct page *page)
{
if (unlikely(PageTransHuge(page)))
return HPAGE_PMD_NR;
return 1;
}
struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr,
pmd_t *pmd, int flags, struct dev_pagemap **pgmap);
struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr,
pud_t *pud, int flags, struct dev_pagemap **pgmap);
extern vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t orig_pmd);
extern struct page *huge_zero_page;
static inline bool is_huge_zero_page(struct page *page)
{
return READ_ONCE(huge_zero_page) == page;
}
static inline bool is_huge_zero_pmd(pmd_t pmd)
{
return is_huge_zero_page(pmd_page(pmd));
}
static inline bool is_huge_zero_pud(pud_t pud)
{
return false;
}
struct page *mm_get_huge_zero_page(struct mm_struct *mm);
void mm_put_huge_zero_page(struct mm_struct *mm);
#define mk_huge_pmd(page, prot) pmd_mkhuge(mk_pmd(page, prot))
static inline bool thp_migration_supported(void)
{
return IS_ENABLED(CONFIG_ARCH_ENABLE_THP_MIGRATION);
}
static inline struct list_head *page_deferred_list(struct page *page)
{
/*
* Global or memcg deferred list in the second tail pages is
* occupied by compound_head.
*/
return &page[2].deferred_list;
}
#else /* CONFIG_TRANSPARENT_HUGEPAGE */
#define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; })
#define HPAGE_PMD_MASK ({ BUILD_BUG(); 0; })
#define HPAGE_PMD_SIZE ({ BUILD_BUG(); 0; })
#define HPAGE_PUD_SHIFT ({ BUILD_BUG(); 0; })
#define HPAGE_PUD_MASK ({ BUILD_BUG(); 0; })
#define HPAGE_PUD_SIZE ({ BUILD_BUG(); 0; })
#define hpage_nr_pages(x) 1
static inline bool __transparent_hugepage_enabled(struct vm_area_struct *vma)
{
return false;
}
static inline bool transparent_hugepage_enabled(struct vm_area_struct *vma)
{
return false;
}
static inline bool transhuge_vma_suitable(struct vm_area_struct *vma,
unsigned long haddr)
{
return false;
}
static inline void prep_transhuge_page(struct page *page) {}
static inline bool is_transparent_hugepage(struct page *page)
{
return false;
}
#define transparent_hugepage_flags 0UL
#define thp_get_unmapped_area NULL
static inline bool
can_split_huge_page(struct page *page, int *pextra_pins)
{
BUILD_BUG();
return false;
}
static inline int
split_huge_page_to_list(struct page *page, struct list_head *list)
{
return 0;
}
static inline int split_huge_page(struct page *page)
{
return 0;
}
static inline void deferred_split_huge_page(struct page *page) {}
#define split_huge_pmd(__vma, __pmd, __address) \
do { } while (0)
static inline void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
unsigned long address, bool freeze, struct page *page) {}
static inline void split_huge_pmd_address(struct vm_area_struct *vma,
unsigned long address, bool freeze, struct page *page) {}
#define split_huge_pud(__vma, __pmd, __address) \
do { } while (0)
static inline int hugepage_madvise(struct vm_area_struct *vma,
unsigned long *vm_flags, int advice)
{
BUG();
return 0;
}
static inline void vma_adjust_trans_huge(struct vm_area_struct *vma,
unsigned long start,
unsigned long end,
long adjust_next)
{
}
static inline int is_swap_pmd(pmd_t pmd)
{
return 0;
}
static inline spinlock_t *pmd_trans_huge_lock(pmd_t *pmd,
struct vm_area_struct *vma)
{
return NULL;
}
static inline spinlock_t *pud_trans_huge_lock(pud_t *pud,
struct vm_area_struct *vma)
{
return NULL;
}
static inline vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf,
pmd_t orig_pmd)
{
return 0;
}
static inline bool is_huge_zero_page(struct page *page)
{
return false;
}
static inline bool is_huge_zero_pud(pud_t pud)
{
return false;
}
static inline void mm_put_huge_zero_page(struct mm_struct *mm)
{
return;
}
static inline struct page *follow_devmap_pmd(struct vm_area_struct *vma,
unsigned long addr, pmd_t *pmd, int flags, struct dev_pagemap **pgmap)
{
return NULL;
}
static inline struct page *follow_devmap_pud(struct vm_area_struct *vma,
unsigned long addr, pud_t *pud, int flags, struct dev_pagemap **pgmap)
{
return NULL;
}
static inline bool thp_migration_supported(void)
{
return false;
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#endif /* _LINUX_HUGE_MM_H */