[PATCH 5.0 110/123] KVM: Fix the bitmap range to copy during clear dirty

[Greg Kroah-Hartman]

From: Peter Xu <peterx@xxxxxxxxxx>

commit 4ddc9204572c33f2eb91fbdb1d99d8078388b67d upstream.

kvm_dirty_bitmap_bytes() will return the size of the dirty bitmap of
the memslot rather than the size of bitmap passed over from the ioctl.
Here for KVM_CLEAR_DIRTY_LOG we should only copy exactly the size of
bitmap that covers kvm_clear_dirty_log.num_pages.

Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 2a31b9db153530df4aa02dac8c32837bf5f47019
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 virt/kvm/kvm_main.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1251,7 +1251,7 @@ int kvm_clear_dirty_log_protect(struct k
 	if (!dirty_bitmap)
 		return -ENOENT;
 
-	n = kvm_dirty_bitmap_bytes(memslot);
+	n = ALIGN(log->num_pages, BITS_PER_LONG) / 8;
 
 	if (log->first_page > memslot->npages ||
 	    log->num_pages > memslot->npages - log->first_page)