diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 0ff6dd775cab45e1a737a70bd137778d45abf6aa..2b753800416db2cb8a0faf666433fd1664d0408f 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -3752,8 +3752,9 @@ The ioctl clears the dirty status of pages in a memory slot, according to
 the bitmap that is passed in struct kvm_clear_dirty_log's dirty_bitmap
 field.  Bit 0 of the bitmap corresponds to page "first_page" in the
 memory slot, and num_pages is the size in bits of the input bitmap.
-Both first_page and num_pages must be a multiple of 64.  For each bit
-that is set in the input bitmap, the corresponding page is marked "clean"
+first_page must be a multiple of 64; num_pages must also be a multiple of
+64 unless first_page + num_pages is the size of the memory slot.  For each
+bit that is set in the input bitmap, the corresponding page is marked "clean"
 in KVM's dirty bitmap, and dirty tracking is re-enabled for that page
 (for example via write-protection, or by clearing the dirty bit in
 a page table entry).
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 06f47308c87e41b956b4811741d6b7e6fed34c6d..d0bcd84b6c8083a5c29cdb89aee68b9fe0b5a6e5 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1288,7 +1288,7 @@ int kvm_clear_dirty_log_protect(struct kvm *kvm,
 	if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_USER_MEM_SLOTS)
 		return -EINVAL;
 
-	if ((log->first_page & 63) || (log->num_pages & 63))
+	if (log->first_page & 63)
 		return -EINVAL;
 
 	slots = __kvm_memslots(kvm, as_id);
@@ -1301,8 +1301,9 @@ int kvm_clear_dirty_log_protect(struct kvm *kvm,
 	n = kvm_dirty_bitmap_bytes(memslot);
 
 	if (log->first_page > memslot->npages ||
-	    log->num_pages > memslot->npages - log->first_page)
-			return -EINVAL;
+	    log->num_pages > memslot->npages - log->first_page ||
+	    (log->num_pages < memslot->npages - log->first_page && (log->num_pages & 63)))
+	    return -EINVAL;
 
 	*flush = false;
 	dirty_bitmap_buffer = kvm_second_dirty_bitmap(memslot);