Gentoo have silently replaced without any prior notice QEmu by its fork KVM. This is documented in:
I am definitely not happy with this kind of initiative and the conclusion of this bug, not because of the replacement in itself but with the lack of a single warning. The next version of Qemu (1.3.x) should see the merge between the both branches of the fork, at least I hope and all stars will be aligned again. Sorry for the inconvenience it may cause, at this point I fear about the severe breakages I can introduce by forking he ebuilds again to have dicstinct Qemu and KVM ebuilds. KVM is not a minor package.
If a major infrastructure is impacted or of many of you are in trouble I will see what I can do to make your lives better...
A real bad habit to change things without notice.
I'd say, they may have update boot-update as well making it incompatible with grub-2.00-r2, hopefully 1.98 will suffice and I can boot but if not I can also just use an overlay for a live version.