Git bisection tells that 5b6fb069378e61c45c577bbec3d7ef60367f7e4c is the first bad commit that breaks support for Solaris/OpenIndiana 32-bit x86 guest with icount 1. Seems like the option rom (kvmvapic.bin) is causing problems. Currently the workaround is to not load the option rom.
Command:
qemu-system-i386 -hda .../solaris.qcow2 -icount 1
Hope someone can take a look or give me pointers on how to proceed to make a patch.