More precisely, Xabi Alonso is currently being targeted by many of Europe's top teams because of Xabi Alonso's success in creating or building the Leverkusen team as it is today. I think it is quite worthy because Xabi Alonso has shown his qualities so it's only natural that many top teams want him.
I think the rumors for Bayern are still quite far away because so far Tauchel has been successful and has made Bayern Munich's performance quite strong, but we don't know at the end of the season what could happen if Tauchel has failed to meet the expectations or targets that have been set by Bayern management.
It's natural that many football teams currently have great interest in Xabi Alonso because if you look at him he is quite successful in managing Leverkusen as an ordinary team and doesn't have a lot of money to buy quality players. But because of his extraordinary ability, he is able to combine players with minimal experience to compete with other strong teams in the Bundesliga and the many good records that Xabi Alonso has achieved this season for himself with Leverkusen.
Both Bayern Munich, Real Madrid and several other teams are still quite open to making offers for him to coach. But I think he will finish one season with Leverkusen and if he succeeds in bringing a title to Leverkusen or finishes as runner-up in the Bundesliga then Real Madrid will move more quickly for him.