diff options
| author | Andreas Sandberg <andreas@sandberg.pp.se> | 2014-01-21 15:49:09 -0800 |
|---|---|---|
| committer | Steve Capper <steve.capper@linaro.org> | 2014-03-05 15:04:50 +0800 |
| commit | 1bf5c38e784b8a4fd7fcc820ea79366e9716b447 (patch) | |
| tree | 61018b97228be217357c86580363737679c7379d | |
| parent | e087bc5eb1ff9c47e9700c78f9d9d72b865f30ab (diff) | |
mm/hugetlb.c: call MMU notifiers when copying a hugetlb page range
When copy_hugetlb_page_range() is called to copy a range of hugetlb
mappings, the secondary MMUs are not notified if there is a protection
downgrade, which breaks COW semantics in KVM.
This patch adds the necessary MMU notifier calls.
Signed-off-by: Andreas Sandberg <andreas@sandberg.pp.se>
Acked-by: Steve Capper <steve.capper@linaro.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/hugetlb.c | 21 |
1 files changed, 16 insertions, 5 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 52caa3d25b6f..96cfebd0d67a 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -2336,16 +2336,26 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, int cow; struct hstate *h = hstate_vma(vma); unsigned long sz = huge_page_size(h); + unsigned long mmun_start; /* For mmu_notifiers */ + unsigned long mmun_end; /* For mmu_notifiers */ + int ret = 0; cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; + mmun_start = vma->vm_start; + mmun_end = vma->vm_end; + if (cow) + mmu_notifier_invalidate_range_start(src, mmun_start, mmun_end); + for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) { src_pte = huge_pte_offset(src, addr); if (!src_pte) continue; dst_pte = huge_pte_alloc(dst, addr, sz); - if (!dst_pte) - goto nomem; + if (!dst_pte) { + ret = -ENOMEM; + break; + } /* If the pagetables are shared don't copy or take references */ if (dst_pte == src_pte) @@ -2365,10 +2375,11 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, spin_unlock(&src->page_table_lock); spin_unlock(&dst->page_table_lock); } - return 0; -nomem: - return -ENOMEM; + if (cow) + mmu_notifier_invalidate_range_end(src, mmun_start, mmun_end); + + return ret; } static int is_hugetlb_entry_migration(pte_t pte) |