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authorSean Christopherson <sean.j.christopherson@intel.com>2020-01-08 12:24:36 -0800
committerPaolo Bonzini <pbonzini@redhat.com>2020-01-27 20:00:01 +0100
commit005ba37cb89bcc0cf63c2029a41f8db165aeb615 (patch)
tree0d0b3d133dfd012cfe53f548397308a7089da89c /include/linux/huge_mm.h
parent22b1d57b032cea4d612746473ed28cb20665d876 (diff)
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: 936a5fe6e6148 ("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>
Diffstat (limited to 'include/linux/huge_mm.h')
-rw-r--r--include/linux/huge_mm.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 0b84e13e88e2..5aca3d1bdb32 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -160,6 +160,7 @@ extern unsigned long thp_get_unmapped_area(struct file *filp,
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);
@@ -308,6 +309,11 @@ static inline bool transhuge_vma_suitable(struct vm_area_struct *vma,
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