Soloing over a rock tune is not that different from playing a blues or funk solo. The most common scales used in these styles are the pentatonic and blues scales. While the blues scale gives you a more bluesy sound as its name says, you can also use the minor pentatonic scale to keep the sound more versatile.
In the following two examples, notes from the E minor pentatonic scale are played over a chord simple progression in the same key. Even though the minor pentatonic consists of only five notes, it can be used very creatively on the piano or keyboard. It consists of E, G, A, B, and D.