There does appear to be a problem with delivery of ISA interrupts for smp,
regardless whether mttcg is enabled or not, though PCI interrupts are working
fine. This appears in that both serial console and ps2 keyboard are
non-responsive, but one can ssh into the guest. Which doesn't make a whole lot
of sense. More debugging required, I suppose.
Hmm weird. I was helping Pranith with debugging one of his aarch64 guest
setups under TCG and it seemed to be loosing IRQs, I could see level=1
breakpoints being hit in qemu_set_irq but no delivery of the IRQ to the
CPU. Unfortunately I had to head home before we got to the bottom of it
but I wonder if it is related.