kvm_main: fix some comments

is_dirty has been renamed to flush, but the comment for it is
outdated. And the description about @flush parameter for
kvm_clear_dirty_log_protect() is missing, add it in this patch
as well.
Signed-off-by: Jiang Biao <benbjiang@tencent.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

virt/kvm/kvm_main.c

@@ -1134,11 +1134,11 @@ EXPORT_SYMBOL_GPL(kvm_get_dirty_log);
 
 #ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT
 /**
- * kvm_get_dirty_log_protect - get a snapshot of dirty pages, and if any pages
+ * kvm_get_dirty_log_protect - get a snapshot of dirty pages
  *	and reenable dirty page tracking for the corresponding pages.
  * @kvm:	pointer to kvm instance
  * @log:	slot id and address to which we copy the log
- * @is_dirty:	flag set if any page is dirty
+ * @flush:	true if TLB flush is needed by caller
  *
  * We need to keep it in mind that VCPU threads can write to the bitmap
  * concurrently. So, to avoid losing track of dirty pages we keep the
@@ -1223,6 +1223,7 @@ EXPORT_SYMBOL_GPL(kvm_get_dirty_log_protect);
  *	and reenable dirty page tracking for the corresponding pages.
  * @kvm:	pointer to kvm instance
  * @log:	slot id and address from which to fetch the bitmap of dirty pages
+ * @flush:	true if TLB flush is needed by caller
  */
 int kvm_clear_dirty_log_protect(struct kvm *kvm,
 				struct kvm_clear_dirty_log *log, bool *flush)