He signed some letters in support of Russian agression, one is in @TGar's answer. Here is another one. Interestingly, it is dated 23 February, so predates the invasion (but I am not sure it appeared on that date)...
Here is a slightly abridged translation (by Google, but quite good).
Who wants victims?
Appeal of Russian writers on the special operation of our army in the Donbass and on the territory of Ukraine.
By publishing this appeal, LG [Literaturnaya gazeta] emphasizes that in the entire polar spectrum of opinions that exist in the current media field, only one thing is undeniable and important: an early end to the bloodshed and suffering of civilians.
The special military operation currently taking place in the Donbass and parts of Ukraine has long been brewing. The West did not stop trying to somehow hurt Russia, denigrate it and eventually dismember it. There is numerous evidence of this: from the declassified NATO military plans to destroy Russia and the constant heaps of lies by American television channels to the physical elimination of people in Ukraine who opposed the fascist ideology.
The anti-Russian hysteria has taken on a special scope since 2014, when the Crimeans freely and almost unanimously decided to join Russia, and the Donbass did not want any more humiliation for speaking and thinking in Russian. And Russia supported these legitimate demands.
Our desire for dialogue, Russia's concerns about security issues were not heard. Discord was deliberately sown with the help of aggressive military actions, fake news, informational provocations and inspirations. For 8 years, we have been patiently persuading all parties to comply with the Minsk agreements, but the West gave Ukraine the unspoken approval to disrupt them.
The pitting of the Slavs among themselves is unacceptable. We Russians don't want to pit anyone against anyone! Russians don't start a war. Russians usually finish it. Russia's special military operation is aimed at bringing peace to Europe.
We love the Ukrainian people, we sing Ukrainian songs, we watch Ukrainian movies, we pray in the same churches. We have common thoughts, and a keen desire to finally breathe in the air of the already near, common spring for our peoples. We have great writers bound by the same spiritual zeal for happiness, freedom, peace, and man. Leo Tolstoy and Nikolai Gogol, Taras Shevchenko and Alexander Pushkin, Lesya Ukrainka and Anna Akhmatova. We have a myriad of common victories and achievements that no one can cross out.
[...]
And what would have happened if the military operation had not begun? If Bandera’s followers had continued their cannibalistic marches around Kiev, they would have killed Ukrainian journalists, the teachers of the Russian language would have been imprisoned, the atrocities of those who burned people alive in Odessa, adopting the tactics of the Nazis, would have hung over Russia dirty Bandera atomic bomb!
So who wants victims? Our troops, who have not yet deliberately destroyed a single civilian? Or those who wage an ongoing linguistic war against the Russian language, as well as an information war against the Russian consciousness? The answer is clear. The West, which has embraced the Nazis, wants victims; they want the Banderlogs, who fraternize with NATO.
And what do we want? We want Ukraine to be sovereign and friendly, prosperous and free. But we don't want it to be ruled by the Nazis.
[...]
Peace be with you, Ukraine! Peace be with you, Russia and Belarus! We are from the same source, and this source of primordial Russia will feed both us and the peoples close to us in spirit, always!