We construct necessary and sufficient geometric conditions for a class of AdS 2 solutions of M-theory with, at least, minimal supersymmetry to exist. We generalize previous results in the literature for N = (2, 0) supersymmetry in AdS 2 to N = (1, 0). When the solution can be locally described as AdS 2 × Σ g × SE 7 with Σ g a Riemann surface of genus g and SE 7 a seven-dimensional Sasaki-Einstein manifold, we clarify and unify various solutions present in the literature. In the case of SE 7 = Q 1,1,1 we find a new solution with baryonic and mesonic charges turned on simultaneously.A There are no AdS 2 solutions with Spin(7)-structure 32 B No AdS 3 solutions within SU(4)-structure AdS 2 class 33 C Killing spinor approach 35