  We construct the holographic dual for $\mathcal N=4$ SYM on $\rm S^4$ and
$\rm AdS_4$ coupled to massive $\mathcal N=2$ supersymmetric quenched flavor
fields on a codimension-1 defect, which is $\rm S^3$ and $\rm AdS_3$,
respectively. The holographic description is in terms of a D3/probe D5 brane
system. We set up and reduce the BPS equations for D5-brane embeddings with
arbitrary supersymmetric deformations and partly solve them at the non-linear
level. The remaining equations are solved explicitly in a small-mass expansion.
We compute the contribution of the defect fields to the partition function on
S$^4$ and compare to a field theory computation using supersymmetric
localization, for which we set up the matrix model. Both computations agree,
lending strong support to holographic probe brane constructions using D3/D5
configurations in general.
