How to monitor backup and restore progress in SQL Server

SELECT session_id as SPID, command, a.text AS Query, start_time, percent_complete, dateadd(second,estimated_completion_time/1000, getdate()) as estimated_completion_time
FROM sys.dm_exec_requests r CROSS APPLY sys.dm_exec_sql_text(r.sql_handle) a
WHERE r.command in ('BACKUP DATABASE','RESTORE DATABASE')

get or disconnect sessions from multiple servers GUI

https://gallery.technet.microsoft.com/scriptcenter/get-or-disconnect-sessions-e7493aef