Ok. This package appears to lack some love. Bugs are never closed (I just closed a few bugreports which were fixed years ago), migration status apparently is never checked, bugs actually are not watched/handled (these 2 bugs are here for quite some time already). I pinged the maintainer but he didn't respond.
I just uploaded virglrenderer package with current issues fixed, so things can be unblocked. Longterm, I'm fine to move this package under qemu umbrella (especially since it is relevant mostly for qemu these days). Thanks, /mjt