diff options
Diffstat (limited to 'drivers/kvm/kvm_main.c')
| -rw-r--r-- | drivers/kvm/kvm_main.c | 22 |
1 files changed, 18 insertions, 4 deletions
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c index ac5ed00e9065..f439e45233f2 100644 --- a/drivers/kvm/kvm_main.c +++ b/drivers/kvm/kvm_main.c @@ -633,7 +633,10 @@ int kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn) } EXPORT_SYMBOL_GPL(kvm_is_visible_gfn); -struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn) +/* + * Requires current->mm->mmap_sem to be held + */ +static struct page *__gfn_to_page(struct kvm *kvm, gfn_t gfn) { struct kvm_memory_slot *slot; struct page *page[1]; @@ -648,12 +651,10 @@ struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn) return bad_page; } - down_read(¤t->mm->mmap_sem); npages = get_user_pages(current, current->mm, slot->userspace_addr + (gfn - slot->base_gfn) * PAGE_SIZE, 1, 1, 1, page, NULL); - up_read(¤t->mm->mmap_sem); if (npages != 1) { get_page(bad_page); return bad_page; @@ -661,6 +662,18 @@ struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn) return page[0]; } + +struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn) +{ + struct page *page; + + down_read(¤t->mm->mmap_sem); + page = __gfn_to_page(kvm, gfn); + up_read(¤t->mm->mmap_sem); + + return page; +} + EXPORT_SYMBOL_GPL(gfn_to_page); void kvm_release_page(struct page *page) @@ -2621,7 +2634,8 @@ static struct page *kvm_vm_nopage(struct vm_area_struct *vma, pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; if (!kvm_is_visible_gfn(kvm, pgoff)) return NOPAGE_SIGBUS; - page = gfn_to_page(kvm, pgoff); + /* current->mm->mmap_sem is already held so call lockless version */ + page = __gfn_to_page(kvm, pgoff); if (is_error_page(page)) { kvm_release_page(page); return NOPAGE_SIGBUS; |