root /var/www/html;
  index index.html;
  ssi on;
  ssi_last_modified on;
}
location ~ \.(php|html)$ {
  root /var/www/html;
  ssi on;
  ssi_last_modified on;
  fastcgi_pass unix:/var/run/php-fpm.sock;
  fastcgi_index index.php;
  fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
  include fastcgi_params;
}
nginxを再起動します。