KVM: Fix the bitmap range to copy during clear dirty

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@redhat.com>
Cc: stable@vger.kernel.org
Fixes: 2a31b9db153530df4aa02dac8c32837bf5f47019
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index ff68b07e94e97c474fa2d501cb1c4f36a4fb81fd..b5238bcba72cbee4f0063a8595b4ace374041ff2 100644 (file)
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1251,7 +1251,7 @@ int kvm_clear_dirty_log_protect(struct kvm *kvm,
        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)