Hi all, Here is hopefully a better explanation of what I poorly described at the meeting today. We have come to agreement that we need to intercept IRQ exceptions, what I am unsure is how to handle them. For synchronous interrupts we do not pass them to the host kernel handler: SWI's that aren't due to translation should be passed along to the guest, UNDEFINED interrupts that isn't because of a system control processor operation is handled the same. I am less certain about synchronous abort interrupts, and whether the host kernel should see these, but that can be a later discussion. For asynchronous interrupts, we obviously want the host kernel to handle the interrupt. I was looking at the architecture and what I am unsure about is what happens if we are in our IRQ interrupt handler and enable for interrupts, would the IRQ be reissued by the hardware or is it lost? If it is reissued that would be great, because when the host code enables for interrupts, our host state is saved and on redispatch we regain control as the host. This is similar to how the PPC code works. If the interrupt would be lost, that means we have to pass the interrupt to the kernel ourselves, but we have to mess around with the registers the real IRQ will save to ensure the host regains control, not the guest (what the registers really were at interrupt). Comments/Suggestions? Brian
