Happy the war was over, decreasing the risk for direct military action between USA and USSR, especially nuclear. Opening up for thawing of relations between the two. Pride in USSR's role as a communicator and at times unofficial mediator in the drawn out peace process ('63-'73). Some pride in the little nation that could somewhat stand up to massive western imperialism. Troubled by the political ground won by USSR's main competitor in SEA - China.

That's the general idea, hard to say how it was practically disseminated in the general public.

Sources: Ilya V. Gaiduk - The Soviet Union and the Vietnam War. Confronting Vietnam: Soviet Policy toward the Indochina Conflict.